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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Synthesis of existing fish population data
SuWa 8
Author(s) – Personal:
Author(s) – Corporate:
Prepared by R2 Resource Consultants, Inc.
AEA-identified category, if specified:
March 01, 2013 Filing
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 8
Existing numbers on document:
Published by:
[Anchorage, Alaska : Alaska Energy Authority, 2013]
Date published:
February 2013
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Attachment B
Final or Draft status, as indicated:
Document type:
Pagination:
xviii, 225, [4] p.
Related work(s):
Cover letter (SuWa 6), Attachments A, C-I (SuWa 7, 9-15)
Pages added/changed by ARLIS:
Added cover letter
Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
March 1, 2013
Ms. Kimberly D. Bose
Secretary
Federal Energy Regulatory Commission
888 First Street, NE
Washington, DC 20426
Re: Susitna-Watana Hydroelectric Project, FERC Project No. 14241-000;
Filing of 2012 Baseline Environmental and Resources Study Reports
Dear Secretary Bose:
As explained in its Pre-Application Document and Revised Study Plan (RSP) for
the proposed Susitna-Watana Hydroelectric Project, FERC Project No. 14241 (Project),
the Alaska Energy Authority (AEA) carried out numerous baseline environmental and
resources studies related to the proposed Project during the 2012 field season. Because
the 2012 studies occurred prior to the commencement of the study phase of the licensing
effort under the Federal Energy Regulatory Commission’s (Commission) Integrated
Licensing Process, AEA was not required to complete these baseline studies. However,
AEA voluntarily undertook these studies for purposes of taking advantage of the 2012
field season to gather environmental data related to the proposed Project, and to help
inform the scope and methods of the licensing studies during 2013-14, as set forth in
AEA’s RSP.
As AEA has completed the study reports associated with these 2012 baseline
environmental and resources studies, it has made the study reports publicly available by
uploading them to the “Documents” page of its licensing website, http://www.susitna-
watanahydro.org/type/documents/. The purpose of this filing is to submit these study
reports to the Commission’s record for the above-referenced Project.
In particular, the following study reports are attached, all of which are relevant to
the Commission’s study plan determination scheduled for April 1, 2013:
• Attachment A: Adult Salmon Distribution and Habitat Utilization Study
(January 2013)
• Attachment B: Synthesis of Existing Fish Population Data (February 2013)
• Attachment C: Mercury Assessment and Potential for Bioaccumulation
(February 2013)
2
• Attachment D: Technical Memorandum, Susitna River Large Woody Debris
Reconnaissance (March 2013)
• Attachment E: Riparian Vegetation Study Downstream of the Proposed
Susitna-Watana Dam (February 2013)
• Attachment F: Technical Memorandum, Reconnaissance Level Assessment of
Potential Channel Change in the Lower Susitna River Segment (February
2013)
• Attachment G: Stream Flow Assessment (February 2013)
• Attachment H: Development of Sediment-Transport Relationships and an
Initial Sediment Balance for the Middle and Lower Susitna River Segments
(February 2013)
• Attachment I: Technical Memorandum, Initial Geomorphic Reach
Delineation and Characterization, Middle and Lower Susitna River Segments
(February 2013)
As the remaining 2012 study reports are finalized, AEA will continue to update its
website and submit them to the record.
If you have questions concerning this submission, please contact me at
wdyok@aidea.org or (907) 771-3955.
Sincerely,
Wayne Dyok
Project Manager
Alaska Energy Authority
Attachments
cc: Distribution List (w/o Attachments)
Attachment B
Synthesis of Existing Fish Population Data (February 2013)
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Synthesis of Existing Fish Population Data
Prepared for
Alaska Energy Authority
Prepared by
R2 Resource Consultants, Inc.
February 2013
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i February 2013
TABLE OF CONTENTS
Summary .......................................................................................................................................xv
1. Introduction ........................................................................................................................1
2. Susitna River Basin Description .......................................................................................3
2.1. Upper River ........................................................................................................4
2.2. Middle River ......................................................................................................4
2.3. Lower River .......................................................................................................4
3. Overview of Existing Studies ............................................................................................6
3.1. 1980 Era Aquatic Studies Program ....................................................................6
4. Habitat Distribution.........................................................................................................12
4.1. Susitna River Upstream of Devils Canyon ......................................................12
4.2. Middle Susitna River Downstream of Devils Canyon .....................................13
4.3. Lower Susitna River ........................................................................................14
5. Adult Salmon ....................................................................................................................17
5.1. Chinook Salmon...............................................................................................17
5.1.1. Abundance/Escapement ................................................................ 17
5.1.2. Distribution ................................................................................... 18
5.1.3. Age of Return ................................................................................ 18
5.1.4. Periodicity ..................................................................................... 19
5.1.5. Holding and Spawning Habitat Utilization ................................... 19
5.2. Sockeye Salmon ...............................................................................................19
5.2.1. Abundance/Escapement ................................................................ 19
5.2.2. Distribution ................................................................................... 20
5.2.3. Age of Return ................................................................................ 22
5.2.4. Periodicity ..................................................................................... 22
5.2.5. Holding and Spawning Habitat Utilization ................................... 22
5.3. Chum Salmon...................................................................................................23
5.3.1. Abundance/Escapement ................................................................ 23
5.3.2. Distribution ................................................................................... 23
5.3.3. Age of Return ................................................................................ 24
5.3.4. Periodicity ..................................................................................... 24
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii February 2013
5.3.5. Holding and Spawning Habitat Utilization ................................... 25
5.4. Coho Salmon ....................................................................................................26
5.4.1. Abundance/Escapement ................................................................ 26
5.4.2. Distribution ................................................................................... 26
5.4.3. Age of Return ................................................................................ 27
5.4.4. Periodicity ..................................................................................... 27
5.4.5. Holding and Spawning Habitat Utilization ................................... 28
5.5. Pink Salmon .....................................................................................................28
5.5.1. Abundance/Escapement ................................................................ 28
5.5.2. Distribution ................................................................................... 29
5.5.3. Periodicity ..................................................................................... 30
5.5.4. Holding and Spawning Habitat Utilization ................................... 30
6. Egg Incubation .................................................................................................................32
6.1. Egg Survival.....................................................................................................32
6.2. Emergence Timing ...........................................................................................34
7. Juvenile Salmon ...............................................................................................................37
7.1. Chinook Salmon...............................................................................................37
7.1.1. Life History Patterns ..................................................................... 37
7.1.2. Periodicity ..................................................................................... 37
7.1.3. Growth .......................................................................................... 38
7.1.4. Habitat Utilization ......................................................................... 38
7.2. Sockeye Salmon ...............................................................................................40
7.2.1. Life History Patterns ..................................................................... 40
7.2.2. Periodicity ..................................................................................... 41
7.2.3. Growth .......................................................................................... 41
7.2.4. Habitat Utilization ......................................................................... 42
7.3. Chum Salmon...................................................................................................43
7.3.1. Life History Patterns ..................................................................... 43
7.3.2. Periodicity ..................................................................................... 43
7.3.3. Growth .......................................................................................... 44
7.3.4. Habitat Utilization ......................................................................... 44
7.4. Coho Salmon ....................................................................................................45
7.4.1. Life History Patterns ..................................................................... 45
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii February 2013
7.4.2. Periodicity ..................................................................................... 45
7.4.3. Growth .......................................................................................... 47
7.4.4. Habitat Utilization ......................................................................... 47
7.5. Pink Salmon .....................................................................................................49
7.5.1. Life History Patterns ..................................................................... 49
7.5.2. Periodicity ..................................................................................... 49
7.5.3. Growth .......................................................................................... 50
7.5.4. Habitat Utilization ......................................................................... 50
7.6. Juvenile Salmon Diet .......................................................................................51
8. Non-salmonids and Resident Fishes ...............................................................................51
8.1. Fish Assemblage ..............................................................................................52
8.2. Distribution, Abundance, and Habitat Utilization ...........................................52
8.2.1. Susitna River Downstream of Devils Canyon .............................. 52
8.2.2. Susitna River Upstream of Devils Canyon ................................... 59
8.3. Age and Size of Selected Resident Fish Species .............................................63
8.4. Invasive Fish Species .......................................................................................63
9. Barriers to migration .......................................................................................................64
9.1. Tributary Barriers.............................................................................................64
9.2. Access to Sloughs ............................................................................................64
10. Access Alignment, Construction Area, and Transmission Alignment ........................66
10.1. Description of 1980s Alignments Pertinent to the Current Project .................66
10.2. Fish Assemblage ..............................................................................................67
10.3. Aquatic Habitat ................................................................................................67
10.4. Water Quality ...................................................................................................68
11. Aquatic Productivity ........................................................................................................69
11.1. Benthic Macroinvertebrates .............................................................................69
11.2. Periphyton ........................................................................................................71
11.3. Water Quality and Chemical Constituents .......................................................71
12. References .........................................................................................................................73
13. Tables ................................................................................................................................82
14. Figures .............................................................................................................................105
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iv February 2013
LIST OF TABLES
Table S-1. Periodicity of adult Pacific salmon presence in the Susitna River. Light gray
indicates total duration of residence and dark gray represents periods of peak use. ............ 83
Table 3.1-1. List of documents related to fish and aquatics studies on the Susitna River from
the 1970s and 1980s. ............................................................................................................. 84
Table 3.1-2. Types of studies conducted as part of the Fish and Aquatics Study Program
during 1981 to 1986. ............................................................................................................. 87
Table 3.1-3. Deployment of fishwheel (F) and sonar stations (S) from 1981 to 1985. ............... 89
Table 3.1-4. Designated Fish Habitat Sites surveyed June through September 1982. ................ 90
Table 3.1-5. Description of habitat zones sampled at Designated Fish Habitat Sites: June
through September 1982 (From Estes and Schmidt 1983). .................................................. 90
Table 3.1-6. Aggregate Hydraulic (H), Water Source (W) and Velocity (V) zones. .................. 91
Table 3.1-7. JAHS sample sites for the AJ and AH components of the Aquatic Studies
Program during 1983 and 1984. ............................................................................................ 92
Table 4.1-1. Characteristics of tributaries upstream of the proposed Devils Canyon Dam as
configured in the 1980s project. ............................................................................................ 94
Table 4.2-1. Black and white aerial photography available for the characterization of aquatic
habitat during the 1980s. ....................................................................................................... 95
Table 4.3-1. Representative areas delineated by habitat type. ..................................................... 95
Table 5.1-1. Information from Buckwalter (2011) Synopsis of ADF&G’s Upper Susitna
Drainage Fish Inventory, August 2011. ................................................................................ 96
Table 5.1-2. Chinook salmon escapement survey results from 1982 to 1985 upstream of RM
152. Surveys conducted by helicopter. ................................................................................ 97
Table 5.2-1. Peak sockeye spawner counts (live plus dead) at sloughs located in the Middle
Susitna River during 1981 to 1985. ...................................................................................... 98
Table 6.2-1. Linear regression statistics for predicting the development of chum and sockeye
eggs based upon average incubation temperature. All equations were significant at
p<0.001 and r-0.99. ............................................................................................................... 98
Table 7.1-1. Periodicity of juvenile Chinook salmon presence in the Susitna River. ................. 99
Table 7.2-1. Periodicity of second run sockeye salmon presence in the middle Susitna River,
between the Chulitna River confluence (RM 98.5) and Devils Canyon (RM 152), by life
history stage. ......................................................................................................................... 99
Table 7.3-1. Periodicity of juvenile chum salmon presence in the Susitna River. .................... 100
Table 7.4-1. Periodicity of juvenile coho salmon in the Susitna River by life history stage. .... 100
Table 7.5-1. Periodicity of juvenile pink salmon presence in the Susitna River by life history
stage. ................................................................................................................................... 100
Table 8.1-1. Fish community in the Susitna River drainage. ..................................................... 101
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page v February 2013
Table 8.1-2. Level of fishing effort at 17 DFH sites in the Lower and Middle Susitna River
segments from June to September 1982. ............................................................................ 102
Table 8.2-1. Estimated Arctic grayling population sizes in tributaries to the upper Susitna
River during 1981 and 1982. .............................................................................................. 104
Table 9.1-1. Tributaries evaluated for passage by adult salmon. ............................................... 104
LIST OF FIGURES
Figure. S-1. Spawning habitat utilization by anadromous salmon species and average run
size in the middle Susitna River. Large arrows indicate primary spawning habitat and
thin arrows indicate secondary spawning habitat. .............................................................. 105
Figure 2.1-1. Susitna River basin map showing field stations and major glacial streams. ........ 106
Figure 3.1-1. Habitat types identified in the middle reach of the Susitna River during the
1980s studies (adapted from ADF&G 1983; Trihey 1982). ............................................... 107
Figure 3.1-2. Sampling effort at 39 habitat locations sites from May to mid-October 1981. .... 108
Figure 3.1-3. Map of Designated Fish Habitat (DFH) sites sampled on the Susitna River,
June through September 1982. ............................................................................................ 109
Figure 3.1-4. Sampling effort at 17 DFH sites during the 1982 open water season. ................. 110
Figure 3.1-5. Hypothetical slough with delineated habitat zones. ............................................. 111
Figure 3.1-6. Sampling effort at 225 mainstem Selected Fish Habitat sites during 1982. ........ 112
Figure 3.1-7. Typical arrangement of transects, grids, and cells at a JAHS site. ...................... 113
Figure 4.1-1. Gradient profile of the Susitna River and the major tributaries within the
impoundment areas of the proposed 1980 project. ............................................................. 114
Figure 4.1-2. Discharge measured at six tributary streams in the Upper Susitna River during
1982. .................................................................................................................................... 115
Figure 4.1-3. Typical substrate observed in Tsusena and Kosina Creeks during 1982. ............ 115
Figure 4.2-1. Relative amounts of habitat types in different areas of the Susitna River at
seven mainstem discharges. ................................................................................................ 116
Figure 4.3-1. Amount of wetted surface area within mainstem channel (top) and side channel
complexes (bottom) at five mainstem discharge levels for four lower river segments. ..... 117
Figure 4.3-2. Proportion of area accounted for by nine habitat types delineated at five
mainstem discharge levels for five sites in the lower Susitna River. .................................. 118
Figure 4.3-3. Area (ft2 on log scale) accounted for by nine habitat types delineated at five
mainstem discharge levels for five sites in the lower Susitna River. .................................. 119
Figure 5.1-1. Deshka River Chinook salmon escapement. ........................................................ 120
Figure 5.1-2. Escapement of Chinook salmon to Susitna River index streams other than the
Deshka River. ...................................................................................................................... 120
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vi February 2013
Figure 5.1-3. Escapement to Sunshine, Talkeetna, and Curry stations based upon
mark-recapture techniques. ................................................................................................. 121
Figure 5.1-4. Distribution of Chinook Salmon spawning in the Susitna River 1976 to 1984. .. 121
Figure 5.1-5. Distribution of Chinook salmon spawning in the Middle River 1982 to 1985. ... 122
Figure 5.1-6. Age of return for Chinook salmon collected at the Sunshine, Talkeetna, and
Curry Stations during 1981 to 1985. ................................................................................... 123
Figure 5.1-7. Upstream migration timing of adult Chinook salmon in the Susitna River
based upon fishwheel catch per unit effort. ........................................................................ 124
Figure 5.1-8. Substrate utilization curve for Chinook salmon based upon measurements at
265 redds. ............................................................................................................................ 124
Figure 5.1-9. Best depth (top) and velocity (bottom) Chinook salmon utilization curves
based upon measurements at 265 redds. ............................................................................. 125
Figure 5.2-1. Escapement of sockeye salmon to the Yentna River 1981 to 2008 based upon
expansion and apportionment of sonar counts. ................................................................... 126
Figure 5.2-2. Second run sockeye salmon escapement estimates to the Susitna River 1981
to 1985. ............................................................................................................................... 126
Figure 5.2-3. Location of fish wheel capture sites, weirs, and radio-tracking stations in the
Susitna River drainage, and the terminal distribution of radio-tagged sockeye salmon
based on aerial surveys, 2007 (top) and 2008 (bottom). ..................................................... 127
Figure 5.2-4. Weighted terminal distribution of sockeye salmon in the Susitna River system
above Sunshine during 2007 (top) and 2008 (bottom). ...................................................... 128
Figure 5.2-5. Distribution of sockeye spawning in Middle Susitna River sloughs. .................. 129
Figure 5.2-6. Age of return for sockeye salmon collected at the Sunshine, Talkeetna, and
Curry Stations during 1981 to 1985. ................................................................................... 130
Figure 5.2-7. Upstream migration timing of second run adult sockeye salmon in the Susitna
River based upon fishwheel catch per unit effort. .............................................................. 131
Figure 5.2-8. Best depth (top) and velocity (bottom) sockeye salmon utilization curves
based upon measurements at 81 redds. ............................................................................... 132
Figure 5.2-9. Substrate utilization curve for sockeye salmon based upon measurements at
81 redds. .............................................................................................................................. 133
Figure 5.3-1. Chum salmon escapement estimates to the Susitna River 1981 to 1985. ............ 133
Figure 5.3-2. Spawning distribution of 210 chum salmon radio-tagged at Flathorn during
2009. .................................................................................................................................... 134
Figure 5.3-3. Chum salmon spawning distribution among tributaries and sloughs in the
Middle Susitna River based upon peak counts. .................................................................. 135
Figure 5.3-4. Age of return for chum salmon collected at the Sunshine, Talkeetna, and
Curry Stations during 1981 to 1985. ................................................................................... 136
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vii February 2013
Figure 5.3-5. Upstream migration timing of adult chum salmon in the Susitna River based
upon fishwheel catch per unit effort. .................................................................................. 137
Figure 5.3-6. Best depth (top) and velocity (bottom) chum salmon utilization curves based
upon measurements at 333 redds. ....................................................................................... 138
Figure 5.3-7. Substrate utilization curve for chum salmon based upon measurements at
33 redds. .............................................................................................................................. 139
Figure 5.4-1. Coho salmon escapement estimates to the Susitna River 1981 to 1985. ............. 140
Figure 5.4-2. Spawning distribution of 275 coho salmon radio-tagged at Flathorn during
2009. .................................................................................................................................... 141
Figure 5.4-3. Coho salmon spawning distribution among tributaries in the Middle Susitna
River based upon peak counts. ............................................................................................ 142
Figure 5.4-4. Age of return for coho salmon collected at the Sunshine, Talkeetna, and Curry
Stations during 1981 to 1985. ............................................................................................. 143
Figure 5.4-5. Upstream migration timing of adult coho salmon in the Susitna River based
upon fishwheel catch per unit effort. .................................................................................. 144
Figure 5.5-1. Pink salmon escapement estimates to the Susitna River 1981 to 1985. ............... 145
Figure 5.5-2. Pink salmon escapement estimates to the Deshka River 1996 to 2012. .............. 145
Figure 5.5-3. Pink salmon spawning distribution among tributaries in the Middle Susitna
River based upon peak counts. ............................................................................................ 146
Figure 5.5-4. Upstream migration timing of adult pink salmon in the Susitna River based
upon fishwheel catch per unit effort. .................................................................................. 147
Figure 6.1-1. Percent survival of chum salmon eggs in artificial redds at eight sites during
the winter of 1984-1985. ..................................................................................................... 148
Figure 6.1-2. Percent size composition of fine substrate (<0.08 in. diameter) of McNeil
samples collected in various habitat types in the middle Susitna River, Alaska. ............... 149
Figure 6.1-3. Percent size composition of fine substrate (<0.08 in. diameter) in McNeil
samples collected at chum salmon redds during May 1984 in study sites of middle
Susitna River, Alaska. ......................................................................................................... 149
Figure 6.1-4. Relationship between percent survival of salmon embryos and the percent of
fine substrate (<0.08 in. diameter) within Whitlock-Vibert Boxes removed from
artificial redds within selected habitats of the middle Susitna River, Alaska. .................... 150
Figure 6.2-1. Mean daily intergravel and surface water temperature data from a spawning
site in Slough 8A. ................................................................................................................ 151
Figure 6.2-2. Summary (mean and range) of intragravel and corresponding surface water
temperature data collected along left (L) and right (R) banks (looking upstream)............. 152
Figure 6.2-3. Embryonic development, hatching, yolk sac absorption, and emergence
data for chum salmon at three sloughs, winter, 1982-1983. ............................................... 153
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page viii February 2013
Figure 6.2-4. Embryonic development, hatching, yolk sac absorption, and emergence
data for sockeye salmon at three sloughs, winter, 1982-1983. ........................................... 154
Figure 6.2-5. Comparison of the timing of development of chum salmon embryos placed
within slough, side channel and mainstem habitats during the winter of 1984-1985. ........ 155
Figure 6.2-6. Temperature regimes for the Susitna River egg-incubation study which simulated
the main-stem river RM 136 (MS), Slough 8A (S2), an intermediate regime (S1), and a
constant 4°C regime (4°). .................................................................................................... 156
Figure 6.2-7. Accumulated temperature units beginning September 3 at four different
temperature regimes for the Susitna River egg-incubation study. ...................................... 156
Figure 6.2-8. Left: days from fertilization to 50 percent hatch (cross- hatched bars) and
complete yolk absorption (open bars). Right: Accumulated temperature units to
reach 50 percent hatch (cross-hatched bars) and complete yolk absorption (open bars). ... 157
Figure 6.2-9. Alevin growth (total length) from 50 percent hatch to complete yolk absorption
for chum and sockeye salmon incubated at three different temperature regimes. .............. 158
Figure 7.1-1. Year of ocean entry by Chinook salmon based upon scale analysis of adults
returning in 1983 and 1984. ................................................................................................ 159
Figure 7.1-2. Chinook salmon (age 0+) daily catch per unit effort and cumulative catch
recorded at the mouth of Indian River. ............................................................................... 160
Figure 7.1-3. Chinook salmon (age 0+) daily catch per unit effort and cumulative catch
recorded at the Talkeetna (upper figure) and Flathorn (lower figure) stationary
outmigrant traps, 1985. ....................................................................................................... 161
Figure 7.1-4. Chinook salmon (age 1+) daily catch per unit effort and cumulative catch
recorded at the Talkeetna (upper figure) and Flathorn (lower figure) stationary
outmigrant traps, 1985. ....................................................................................................... 162
Figure 7.1-5. Mean length of Chinook fry captured at outmigrant traps during 1984 and
1985. .................................................................................................................................... 163
Figure 7.1-6. Mean length of Chinook Age 1+ captured at outmigrant traps during 1984. ...... 164
Figure 7.1-7. Density distribution and juvenile Chinook salmon by macrohabitat type on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 165
Figure 7.1-8. Seasonal distribution and relative abundance of juvenile Chinook salmon on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 166
Figure 7.2-1. Year of ocean entry by sockeye salmon based upon scale analysis of adults
returning in 1983 and 1984. ................................................................................................ 167
Figure 7.2-2. Sockeye salmon (age 0+) daily catch per unit effort and cumulative catch
recorded at the Talkeetna Station outmigrant traps, 1984. ................................................. 168
Figure 7.2-3. Sockeye salmon (age 0+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1985. .................................................................................................................................... 169
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ix February 2013
Figure 7.2-4. Sockeye salmon (age 1+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1985. .................................................................................................................................... 170
Figure 7.2-5. Mean length of sockeye salmon fry and Age 1+ captured at outmigrant traps
during 1984 and 1985. ........................................................................................................ 171
Figure 7.2-6. Density distribution and juvenile sockeye salmon by macrohabitat type on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 172
Figure 7.2-7. Seasonal distribution and relative abundance of juvenile sockeye salmon on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 173
Figure 7.3-1. Chum salmon (age 0+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper) and Flathorn (lower) station outmigrant traps, 1984. .................. 174
Figure 7.3-2. Chum salmon (Age 0+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1985. .................................................................................................................................... 175
Figure 7.3-3. Mean length of sockeye salmon fry captured at outmigrant traps during 1984. .. 176
Figure 7.3-4. Density distribution and juvenile chum salmon by macrohabitat type on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 177
Figure 7.3-5. Seasonal distribution and relative abundance of juvenile chum salmon on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 178
Figure 7.4-1. Year of ocean entry by coho salmon based upon scale analysis of adults
returning in 1983 and 1984. ................................................................................................ 179
Figure 7.4-2. Coho salmon (age 0+) daily catch per unit effort and cumulative catch
recorded at the mouth of Indian River. ............................................................................... 180
Figure 7.4-3. Coho salmon (age 0+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1985. .................................................................................................................................... 181
Figure 7.4-4. Coho salmon (age 0+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1984. .................................................................................................................................... 182
Figure 7.4-5. Coho salmon (Age 1+) daily catch per unit effort and cumulative catch recorded
at the Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps,
1985. .................................................................................................................................... 183
Figure 7.4-6. Mean length of coho fry captured at outmigrant traps during 1984 and 1985. .... 184
Figure 7.4-7. Mean length of coho salmon Age 1+ captured at outmigrant traps during
1984 and 1985. .................................................................................................................... 185
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page x February 2013
Figure 7.4-8. Density distribution and juvenile coho salmon by macrohabitat type on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 186
Figure 7.4-9. Seasonal distribution and relative abundance of juvenile coho salmon on the
Susitna River between the Chulitna River confluence and Devils Canyon, May through
November 1983. .................................................................................................................. 187
Figure 7.5-1. Pink salmon fry daily catch per unit effort and cumulative catch recorded at
the Talkeetna (upper) and Flathorn (lower) station outmigrant traps, 1984. ...................... 188
Figure 7.5-2. Pink salmon fry daily catch per unit effort and cumulative catch recorded at the
Talkeetna (upper figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. .. 189
Figure 7.6-1. Stomach contents of Chinook, sockeye, and coho salmon juveniles during
summer and fall 1977. ......................................................................................................... 190
Figure 7.6-2. Frequency of food items by taxonomic group and guild within stomach
contents of 72 juvenile Chinook salmon collected during 1984. ........................................ 191
Figure 8.2-1. Total catch of rainbow trout at DFH sites within the middle and lower Susitna
River segments during 1982. .............................................................................................. 192
Figure 8.2-2. Total catch of Artic grayling at DFH sites in the Lower and Middle Susitna
River during 1982. .............................................................................................................. 193
Figure 8.2-3. Total catch of burbot at DFH sites during 1982 by gear type. ............................. 194
Figure 8.2-4. CPUE of burbot at DFH sites during 1982. ......................................................... 195
Figure 8.2-5. Total catch of round whitefish at DFH sites during 1982 by gear type. .............. 196
Figure 8.2-6. Total catch of humpback whitefish at DFH sites during 1982 by gear type. ....... 197
Figure 8.2-7. Total catch of longnose sucker at DFH sites during 1982 by gear type. ............. 198
Figure 8.2-8. Total catch of Dolly Varden at DFH sites during 1982 by gear type. ................. 199
Figure 8.2-9. Total catch of threespine stickleback at DFH sites during 1982 by gear type. .... 200
Figure 8.2-10. Mean hourly fishwheel catch of Bering cisco by two day periods at Sunshine
Station. ................................................................................................................................ 201
Figure 8.2-11. Mean CPUE of prespawning eulachon, tidal ranges, and temperature at the
Susitna River estuary, 1982. ............................................................................................... 202
Figure 8.2-12. Frequency distributions of instantaneous water depths (top) and velocities
(bottom) measured at sites at which eulachon spawning habitat surveys were conducted
during1982 and 1983. ......................................................................................................... 203
Figure 8.2-13. Total catch of slimy sculpin at DFH sites during 1982 by gear type. ................ 204
Figure 8.2-14. Catch per unit effort of Artic grayling by hook and line in tributaries to the
Upper Susitna River during 1981 and 1982. ....................................................................... 205
Figure 8.2-15. Total catch of burbot by trotlines during 1981 (top) at tributary mouths and
CPUE of burbot at mainstem sites in the Upper Susitna River during 1982 (bottom). ...... 206
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Figure 8.2-16. Bathymetric map of Sally Lake. ......................................................................... 207
Figure 8.3-1. Age and length of rainbow trout collected in the Lower and Middle Susitna
River during the open water seasons of 1981, 1982, and 1983. ......................................... 208
Figure 8.3-2. Age and length of longnose sucker collected in the lower, middle, and upper
Susitna River during the open water seasons of 1981, 1982, and 1983. ............................. 209
Figure 8.3-3. Age and length of longnose sucker collected in the lower, middle, and upper
Susitna River during the open water seasons of 1981, 1982, and 1983. ............................. 210
Figure 8.3-4. Age and length of longnose sucker collected in the lower, middle, and upper
Susitna River during the open water seasons of 1981 and 1982. ........................................ 211
Figure 8.3-5. Age and length of round whitefish collected in the lower, middle, and upper
Susitna River during the open water seasons of 1981, 1982, and 1983. ............................. 212
Figure 8.3-6. Age and length of humpback whitefish collected in the Lower and Middle
Susitna River during the open water seasons of 1981, 1982, and 1983. ............................. 213
Figure 8.3-7. Age and length of Bering cisco collected in the Lower Susitna River during
the open water seasons of 1981. ......................................................................................... 214
Figure 8.3-8. Length frequency of Dolly Varden (top) and Arctic lamprey (bottom) collected
in the Susitna River downstream of Devils Canyon during the open water season of
1981. .................................................................................................................................... 215
Figure 9.2-1. Chum spawning areas in Slough 9 during 1982................................................... 216
Figure 9.2-2. Thalweg profile of Slough 9. ............................................................................... 217
Figure 11.1-1. Velocity habitat suitability indices for benthic invertebrate guilds based upon
sampling in the Middle Susitna River during 1984. ........................................................... 218
Figure 11.1-2. Substrate habitat suitability indices for benthic invertebrate guilds based
upon sampling in the Middle Susitna River during 1984. .................................................. 219
Figure 11.1-3. Projections of gross surface area and WUA of burrower, swimmer, clinger,
and sprawler invertebrate habitat as a function of site flow and mainstem discharge for
the Slough 9 modeling site. ................................................................................................. 220
Figure 11.3-1. Levels of orthophosphate (top) and nitrate (bottom) measured at seven
stations. ............................................................................................................................... 221
Figure 11.3-2. Turbidity and temperature measured at the Gold Creek Station and discharge
measured at the Talkeetna Station during 1984. ................................................................. 222
Figure 11.3-3. Range of turbidity during breached and unbreached conditions at twelve side
sloughs and side channels. .................................................................................................. 223
Figure 11.3-4. Seasonal water temperature in the Upper Susitna River during 1980 (top) and
summary of discrete water temperature measurements at seven stations along the Susitna
River (bottom). .................................................................................................................... 224
Figure 11.3-5. Temperature gradient in the Susitna River from RM 26 to 291. ....................... 225
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APPENDICES
Appendix 1. Index of Location Names and River Mile
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LIST OF ACRONYMS AND SCIENTIFIC LABELS
Abbreviation Definition
ADF&G Alaska Department of Fish and Game
AEA Alaska Energy Authority
APA Alaska Power Authority
cfs cubic feet per second
Confluence The junction of two or more rivers or streams.
Cross-section A plane across a river or stream channel perpendicular to the direction of water
flow.
DIDSON
Dual Frequency Identification Sonar. Sonar imaging instrumentation developed by
Sound Metrics Corp. with applications for fish enumeration, behavior and habitat
mapping.
Drainage area The total land area draining to any point in a stream. Also called catchment area,
watershed, and basin.
El. elevation
FERC Federal Energy Regulatory Commission
Fishwheel
A device for catching fish which operates much as a water-powered mill wheel. A
wheel complete with baskets and paddles is attached to a floating dock. The wheel
rotates due to the current of the stream it is placed into. The baskets on the wheel
capture fish traveling upstream. The fish caught in the baskets fall into a holding
tank.
Floodplain
1. The area along waterways that is subject to periodic inundation by out-of-bank
flows. 2. The area adjoining a water body that becomes inundated during periods of
over-bank flooding and that is given rigorous legal definition in regulatory programs.
3. Land beyond a stream channel that forms the perimeter for the maximum
probability flood. 4. A relatively flat strip of land bordering a stream that is formed by
sediment deposition. 5. A deposit of alluvium that covers a valley flat from lateral
erosion of meandering streams and rivers.
fps feet per second
Fyke net Fyke/Hoop nets are tubular shaped nets with a series of hoops or rings spaced
along the length of the net to keep it open.
Geomorphology The scientific study of landforms and the processes that shape them.
Gradient The rate of change of any characteristic, expressed per unit of length (see Slope).
May also apply to longitudinal succession of biological communities.
Groundwater (GW) In the broadest sense, all subsurface water; more commonly that part of the
subsurface water in the saturated zone.
Hydraulic model A computer model of a segment of river used to evaluate stream flow
characteristics over a range of flows.
Hyporheic
The hyporheic zone is the subsurface volume of sediment and porous space
beneath and lateral to a river or streambed, where there is mixing of shallow
groundwater and surface water.
Ice cover A significant expanse of ice of any form on the surface of a body of water.
Ice-free No floating ice present.
Inclined plane trap
This trap consists of a revolving screen suspended between two pontoons.
Downstream migrant fish reaching the back of the trap are dropped into a live box
where they can later be enumerated.
Intergravel Intergravel refers to the subsurface environment within the riverbed.
Macroinvertebrate An invertebrate animal without a backbone that can be seen without magnification.
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Abbreviation Definition
Mainstem
Mainstem refers to the primary river corridor, as contrasted to its tributaries.
Mainstem habitats include the main channel, split main channels, side channels,
tributary mouths, and off-channel habitats.
mg milligram
mg/L milligrams per liter
mi mile(s)
mi2; sq.mi. square mile(s)
Minnow trap Normally composed of small steel mesh with 2-piece torpedo shape design, this
trap is disconnected in the middle for easy baiting and fish removal.
mph miles per hour
NCI Northern Cook Inlet
NMFS NOAA National Marine Fisheries Service
NTU nephelometric turbidity unit
ºC degrees Celsius
ºF degrees Fahrenheit
Open lead Elongated opening in the ice cover caused by water current (velocity lead) or warm
water (thermal lead).
Project Susitna-Watana Hydroelectric Project
Riparian Pertaining to anything connected with or adjacent to the bank of a stream or other
body of water.
River mile The distance of a point on a river measured in miles from the river's mouth along
the low-water channel.
RM River Mile(s) referencing those of the 1980s APA Project and designated within
R&M (1981).
Seine (beach)
A fishing net that hangs vertically in the water with its bottom edge held down by
weights and its top edge buoyed by floats. Seine nets can be deployed from the
shore as a beach seine, or from a boat.
Slope The inclination or gradient from the horizontal of a line or surface.
Thalweg A continuous line that defines the deepest channel of a watercourse.
Three Rivers Confluence
The confluence of the Susitna, Chulitna, and Talkeetna rivers at Susitna River Mile
(RM) 98.5 represents the downstream end of the Middle River and the upstream
end of the Upper River.
Tributary A stream feeding, joining, or flowing into a larger stream (at any point along its
course or into a lake). Synonyms: feeder stream, side stream.
Trotline
A heavy fishing line with baited hooks attached at intervals by means of branch
lines called snoods. A snood is a short length of line which is attached to the main
line using a clip or swivel, with the hook at the other end.
TWG Technical Workgroup
Upwelling
The movement of groundwater into rivers, stream, sloughs and other surface water
features. This is also called groundwater discharge and may be associated with a
gaining reach of a river or stream.
USACE U.S. Army Corps of Engineers
USFWS DOI, Fish and Wildlife Service
USGS DOI, Geological Survey
Wetted channel width (wetted
Perimeter)
The length of the wetted contact between a stream of flowing water and the stream
bottom in a plane at right angles to the direction of flow.
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SUMMARY
The Alaska Energy Authority (AEA) is preparing a license application that will be submitted to
the Federal Energy Regulatory Commission for the Susitna-Watana Hydroelectric Project
(Project) located on the Susitna River, which drains into Cook Inlet located in Southcentral
Alaska. The Susitna River drainage covers about 19,400 square mi. The Susitna River is
approximately 300 miles long and joined by two major rivers, the Chulitna (river mile [RM] 98)
and Talkeetna (RM 97), in the vicinity of the town of Talkeetna. A third major tributary, the
Yentna River (RM 28), joins the Susitna River about 70 mi farther downstream. The Chulitna
River is the largest of the tributaries joining the Susitna River.
The proposed Project dam is located at RM 184. As currently envisioned, the Project would
include a large dam with a 20,000-acre, 39-mile long reservoir. Project construction and
operation would have an effect on the flows downstream of the dam site, the degree of which
will ultimately depend on final Project design and operating characteristics. Key flow changes
will likely occur in the form of load following during the winter months of November through
April each year. Seasonal variation in flows will occur with flows higher during the winter
months and lower during reservoir refill, and drafting of the reservoir during the winter months.
If operated in this fashion, Project operations would cause seasonal, daily, and hourly changes in
Susitna River flows compared to existing conditions. The potential alteration in flows would
influence downstream resources and processes, including fish and aquatic biota and their
habitats, channel form and function including sediment transport, water quality,
groundwater/surface water interactions, ice dynamics and riparian and wildlife communities
(AEA 2011).
Development of hydroelectric facilities on the Susitna River has been considered since the early
1950s (USFWS 1952). The Alaska Power Authority (APA) prepared a formal proposal to the
Federal Energy Regulatory Commission (FERC) in the early 1980s (FERC No. 7114). The
FERC No. 7114 project was proposed as a two dam development with a storage dam and power
plant located at RM 184, the location of the currently proposed Watana Dam site, and a re-
regulating dam located at RM 152 near the downstream end of Devils Canyon. Because of
falling energy prices, further development of FERC No. 7114 was halted in 1986 (AEA 2011).
The objective of this technical memorandum (TM) is to summarize the available contemporary
and historical fish and aquatic studies to support the development and implementation of studies
needed to understand the potential effects of the proposed Susitna-Watana Hydroelectric Project.
The summary is focused on the studies conducted by the Alaska Department of Fish and Game
and Trihey and Associates during the 1980s as part of the Susitna-Hydroelectric Aquatics
Studies Program. The number of reports produced as part of the Su-Hydro Aquatic Studies
Program included over 80 volumes and several thousand pages of text, maps, charts, and tabular
summaries, and raw data tables. By intention, this TM is selective in the subjects covered and
relatively coarse in the level of detail provided for any specific subject area. The reader is
encouraged to pursue the source reports for a higher level of detail on the methods, results, and
conclusions that can be drawn from the studies conducted as part of the Aquatic Studies
Program.
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The Aquatic Studies Program had three components: Adult Anadromous Fish Studies (AA),
Resident and Juvenile Anadromous Fish Studies (RJ), and Aquatic Habitat and Instream Flow
Studies (AH). In addition to work completed by ADF&G, the AH component included work
conducted by Trihey and Associates. The objectives for each of the components were (Schmidt
and Bingham 1983):
AA – determine the seasonal distribution and relative abundance of adult anadromous
fish populations produced within the study area;
RJ – determine the seasonal distribution and relative abundance of selected resident and
juvenile anadromous fish populations within the study area; and
AH – characterize the seasonal habitat requirements of selected anadromous and resident
fish species within the study area and the relationship between the availability of these
habitat conditions and the mainstem discharge of the Susitna River.
Field studies were conducted monthly from November 1980 through October 1985, except for
periods of freeze-up and ice-off, which were too risky and unsafe for equipment and staff. Fish
surveys were a challenge because of high turbidity during most of late spring and summer
seasons, except in tributaries mouths, and side channels and sloughs affected by groundwater or
clearwater tributary inflow. In contrast, during fall and winter most of the river has complete ice
cover, except in areas of small open leads that resulted from groundwater inflow and water
velocity. In general, RJ and AH studies were broad-based during 1981 and 1982 with the widest
geographic scale and sampling methods. As the Aquatic Studies Program progressed, studies
became more focused on acquiring specific information needs for habitat modeling and
acquisition of specific biological data. In addition, the results of 1981 and 1982 fish distribution
and habitat utilization studies led to more intensive sampling at fewer sites with known fish use.
A major objective of the 1980s Aquatic Studies Program was to understand the seasonal fish use
of six mainstem (macro-) habitat types. The six mainstem habitat types consisted of mainstem
(main channel), side channel, side slough, upland slough, tributaries, and tributary mouths
(ADF&G 1984). The major fish species studied as part of the Aquatic Studies Program included
Chinook salmon (Oncorhynchus tshawytscha), chum salmon (O. keta), sockeye salmon (O.
nerka), coho salmon (O. kisutch), rainbow trout (O. mykiss), burbot (Lota lota), eulachon
(Thaleichthys pacificus), and Arctic grayling (Thymallus arcticus). Pink salmon (O. gorbuscha)
are also present in the Susitna River in large numbers; however the species was relatively
unimportant in the studies, because they spawned almost exclusively in tributary streams, and fry
outmigration was nearly complete before open water sampling could occur. In addition, pink
salmon have a relatively low commercial and sport fishing value compared to the other salmon
species. Consequently, pink salmon were monitored as part of the AA component, but played a
minor role in the RJ component, and no role in the AH component.
From 1981 to 1985, fishwheels and sonar were deployed at Flathorn Station (RM 18.2) or
Susitna Station (RM 25.5), Sunshine Station (RM 80.0), Talkeetna Station (RM 103.0), Curry
Station (RM 120.0), and the Yentna River Station (RM 30.1, tributary river mile [TRM] 4.0).
The techniques provided a relatively good understanding of adult salmon run timing. The
periodicity of adult salmon presence and spawning are summarized in Table S-1. Chinook
salmon and sockeye salmon (first-run) were the first adult salmon to enter the Susitna River, and
they were followed by pink salmon and sockeye salmon (second run), chum salmon, and coho
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salmon. First run sockeye salmon spawned in the Yentna River and other lower river tributaries,
but did not spawn in the middle river.
Chinook salmon and sockeye salmon (first-run) were the first adult salmon to enter the Susitna
River, and they were followed by pink salmon and sockeye salmon (second run), chum salmon,
and coho salmon. First run sockeye salmon spawned in the Yentna River and other lower river
tributaries, but did not spawn in the middle river.
An important discovery in 1982 was the observation of Chinook salmon spawning upstream of
Devils Canyon (Barrett et al. (1983). Anecdotal observations of salmon upstream of Devils
Canyon were reported in the late 1950s (USFWS 1957), but were not confirmed until the 1980s.
Since that time, relatively small numbers of Chinook salmon have been documented spawning in
tributary streams upstream of Devils Canyon to the Oshetna River (Buckwalter 2011). To date,
no other salmon species has been observed to pass Devils Canyon. The hydrologic conditions
under which passage through Devils Canyon is possible are uncertain but are thought to occur
around a relatively narrow discharge level (AEA unpublished data).
One of the early conclusions from the surveys conducted during 1981 and 1982 was that little to
no salmon spawning occurred in the main channel habitats because of high water velocities and
unsuitable spawning substrate. Mainstem substrates generally consisted of boulder and cobble
size materials with interstitial spaces filled with a grout-like mixture of small gravels and glacial
sands (Estes and Schmidt 1983). In contrast, the more protected side channels and side sloughs
often included smaller substrate that was occasionally disturbed during high flow events that
breached berms at the head of the channel or slough. In addition, many side channels and
sloughs had upwelling from hyporheic or groundwater sources that provided more stable and
higher temperatures during egg incubation than mainstem water (ADF&G 1982b).
Spawning surveys conducted during the 1980s suggested the Lower Susitna River (i.e.,
downstream of the confluence of the Chulitna, Talkeetna, and Susitna Rivers near RM 98) was
primarily a migration corridor for adult salmon accessing a number of substantial tributaries for
spawning (e.g., Montana Creek, Birch Creek, Willow Creek, Deshka River, etc.). Six chum
salmon spawning locations were identified in 1981 (ADF&G 1981); however, it was reported
that chum salmon did not spawn in the 811 mainstem sites surveyed in the lower river during
1982 (Barrett et al. 1983). Similarly, Barrett et al. (1983) reported that sockeye salmon did not
spawn at any of the sites checked. Mainstem spawning surveys were not conducted during 1983.
During 1984, Barrett et al. (1985) identified 3,400 to 5,125 chum salmon spawning at thirteen
mainstem sites, five sloughs, and five tributary mouths. A few coho salmon were also observed
spawning at three sites. The unexpected use of these lower river mainstem sites and sloughs for
spawning by a relatively large number of chum salmon resulted in additional instream flow
modeling and egg incubation monitoring at six of the sites (Bigler and Levesque 1985).
Spawning surveys from 1981 through 1985 (ADF&G 1981, Barrett et al. 1983, ADF&G 1984,
Barrett et al. 1985, Thompson et al. 1986) indicated that Chinook salmon and coho salmon
spawn exclusively in tributary streams, while pink salmon spawn primarily in tributary streams,
but may occasionally spawn in side channels or side sloughs (Figure S-1). Sockeye salmon in
the middle Susitna River spawn exclusively in side sloughs; no lakes associated with tributary
streams draining to the middle river support sockeye salmon spawning or rearing. Chum salmon
in the middle Susitna River primarily spawn in side sloughs and tributaries, but occasionally
spawn in side channels and mainstem channel edges. Based upon the preferred spawning
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Susitna-Watana Hydroelectric Project Alaska Energy Authority
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habitat, ADF&G concluded that chum salmon and sockeye salmon spawning and incubation
habitat were at higher risk of adverse effects from hydroelectric development on the Susitna
River compared to Chinook salmon, coho salmon, and pink salmon spawning and incubation
habitat (Jennings 1985).
Tributary surveys were also conducted in the upper Middle and Upper Susitna River (i.e.,
upstream of the proposed Devils Canyon Dam). These focused primarily on portions of 11
tributaries that would be inundated by the proposed dams (Delaney et al. 1981c, Sautner and
Stratton 1983). These included Cheechako Creek, (RM 152.4), Chinook salmon Creek (RM
157.0), Devil Creek (RM 161.4), Fog Creek (RM 173.9), Tsusena Creek (RM 178.9), Deadman
Creek (RM 183.4), Watana Creek (RM 190.4), Kosina Creek (RM 202.4), Jay Creek (RM
203.9), Goose Creek (RM 224.9), and Oshetna River (RM 226.9). Only the latter eight streams
were surveyed during 1981. During 1982 seven sloughs in the mainstem were also sampled.
The fish community in tributaries was much less diverse in the Upper Susitna River compared to
the lower Middle and Lower Susitna River. The tributaries were dominated by Arctic grayling
and relatively few Dolly Varden (Salvelinus malma). Burbot, longnose sucker (Catostomus
catostomus), and round whitefish (Prosopium cylindraceum). A few humpback whitefish
(Coregonus pidschian) were observed in the mainstem Susitna River at tributary confluences.
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
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1. INTRODUCTION
The Alaska Energy Authority (AEA) is preparing a license application that will be submitted to
the FERC for the Susitna-Watana Hydroelectric Project (Project) using the Integrated Licensing
Process. The Project dam is located at RM 184 on the Susitna River, an approximately 300-mile
long river in the Southcentral region of Alaska. As currently envisioned, the Project would
include a large dam with a 20,000-acre, 39-mile long reservoir. Project construction and
operation would have an effect on the flows downstream of the dam site, the degree of which
will ultimately depend on final Project design and operating characteristics. Key flow changes
will likely occur in the form of load following during the critical winter months of November
through April each year, seasonal variation with flows higher during the winter months and
lower during reservoir refill, and drafting of the reservoir during the winter months. Project
operations would cause seasonal, daily, and hourly changes in Susitna River flows compared to
existing conditions. The potential alteration in flows would influence downstream resources and
processes, including fish and aquatic biota and their habitats, channel form and function
including sediment transport, water quality, groundwater/surface water interactions, ice
dynamics and riparian and wildlife communities (AEA 2011).
Development of hydroelectric facilities on the Susitna River has been considered since the early
1950s (Friese 1975). The U.S. Army Corps of Engineers were authorized in 1972 by the U.S.
Senate to investigate development near Devils Canyon and the National Marine Fisheries Service
contracted with the Alaska Department of Fish and Game (ADFG) to assess salmon populations
in the Susitna River (Friese 1975). The Alaska Power Authority (APA) prepared a formal
proposal to the Federal Energy Regulatory Commission (FERC) in the early 1980s (FERC No.
7114). The FERC No. 7114 project was proposed as a two dam development with a storage dam
and power plant located at river mile1 (RM) 184, the location of the currently proposed Watana
Dam site, and a re-regulating dam located at RM 152 near the downstream end of Devils
Canyon. Because of falling energy prices, further development of FERC No. 7114 was halted in
1986 (AEA 2011).
In addition to fisheries studies conducted by ADFG in 1974 and 1975, APA contracted with
ADFG to conduct a series of fish and aquatic studies from 1981 through 1985. More recent
studies include on-going monitoring in support of sport and commercial fisheries in the Cook
Inlet Region. Annual index reaches are surveyed for spawning salmon and sonar and fish wheel
counts were made on an annual basis.
The objective of this technical memorandum (TM) is to summarize the available contemporary
and historical fish and aquatic studies to support the development and implementation of studies
needed to understand the potential effects of the proposed Susitna-Watana Hydroelectric Project.
Because the number of studies is voluminous, the focus of this TM is on the ADFG studies
conducted during the 1980s, but pertinent studies from the 1970s, late-1990s, and 2000s are also
presented. Specific objectives include the synthesis of the information identified below.
1 River miles are those used in the 1980s studies and designated within R&M (1981).
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Synthesize existing information on life history, spatial and temporal distribution, and
relative abundance by species and life stage.
Synthesize recent ADF&G run apportionment and timing data for sockeye salmon, coho
salmon, and chum salmon.
Prepare periodicity charts for each species within the study area (timing of adult
migration, holding, and spawning; timing of incubation, rearing, and outmigration).
Summarize mainstem Susitna River habitat utilization for each species, by riverine
habitat type (main channel, side channel, side slough, upland slough, tributary mouth,
tributary).
Summarize existing age, size, and genetics information.
Summarize distribution of invasive species, such as northern pike (Esox lucius).
Summarize seasonal distribution of macroinvertebrates by riverine habitat types.
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
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2. SUSITNA RIVER BASIN DESCRIPTION
The Susitna River drainage area is about 19,400 mi2 and located in the Southcentral portion of
Alaska (Figure 2.1-1). The Susitna River is joined by two major rivers, the Chulitna (RM 98)
and Talkeetna (RM 97), about 40 miles downstream of Gold Creek in the vicinity of the town of
Talkeetna. A third major tributary, the Yentna River (RM 28), joins the Susitna River about 70
miles farther downstream.
The Susitna-Watana Hydroelectric Project area lies near the border of the Continental and
Transitional climate zones of Alaska (AEA 2012). Continental Zone temperatures in the summer
average around 60°F (15°C). Mean lows in the winter are near minus10°F (minus 23°C), with
minus 45°F (minus 43°C) to minus 55°F (minus 48°C) on occasion. Annual precipitation is
generally about 10 inches with the majority falling within the summer months. Where
orographic lift occurs, annual precipitation totals may exceed 20 inches. In general, this zone is
located south of the Brooks Range and inland. The sun does not set for more than a month
during the summer and likewise does not rise for more than month during winter. Surface winds
are lighter than those in the Arctic.
The Transitional Zone includes the region around the Cook Inlet and the lower Susitna River.
The coolest month in Transitional Zone has temperature averages between 20°F (minus 3°C) and
64°F (18°C) while the warmest month is generally above 50°F (10°C). In addition, it is
considered to only have one to three months with a high temperature above 50°F (10°C).
Moderate moisture is present in all seasons. Winds are moderate, skies are usually cloudy, and
the relative humidity is moderate to high. In addition, heavy fog is very frequent as a result of
maritime influences. Both continental and maritime climate systems affect the Transitional
Zone.
In general, the Susitna River was divided in the 1980s studies into three reaches:
1. Upper River – Representing that portion of the watershed above the proposed Devils
Canyon Dam site at RM 152;
2. Middle River – Extending approximately 53.5 miles from RM 152 downstream through
Devils Canyon to the confluence of the three rivers at RM 98.5; and
3. Lower River – Extending the entire 98.5 miles downstream from the three rivers
confluence to Cook Inlet (RM 0).
In contrast to the 1980s reach designations, the contemporary Project has designated the Upper
River segment as the reach extending upstream from the proposed Watana Dam site and the
Middle River as the reach extending from the confluence of the three rivers to the proposed
Watana Dam (AEA 2011). Under the current Project, the Middle River segment is further
delineated into three subreaches including the lower Middle River from RM 98.5 to downstream
end of Devils Canyon at RM 150, the middle Middle River from RM 150 to Devil Creek (RM
161) at the upper end of Devils Canyon, and the upper Middle River from RM 161 to the
proposed Watana Dam site.
The following provides a general description of the three river segments as delineated for the
current Project.
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2.1. Upper River
The drainage area upstream of the proposed location of the Watana Dam (RM 184) is about
5,180 mi2. The Upper Susitna River (i.e., area upstream of the proposed dam site) is fed by three
glaciers in the Alaskan Range. The glaciers cover an area of 290 mi2 (Acres 1983). The three
glacially fed forks, including the Maclaren River, flow southward for about 18 miles before
joining to form the mainstem of the Susitna River. The river flows an additional 55 miles
southward through a broad valley, where much of the coarse sediment from the glaciers settles
out. The river then flows west about 56 miles to the proposed Watana Dam site. Other
tributaries that flow into the proposed reservoir include Deadman, Watana (RM 194), Kosina
(RM 206.8), Goose (RM 231.3), and Jay creeks, along with the Oshetna River (RM 233.4).
2.2. Middle River
Downstream of the proposed dam site, the Susitna River continues west for about 40 mi through
the Devils Canyon area; the river valley in this segment is narrow with violent rapids. Within the
96-mile westward section of the Susitna River, there are numerous small, steep gradient, clear
water tributaries that flow into the Susitna River. Several of these tributaries traverse waterfalls
as they enter the gorge. Tributaries located between the proposed dam site and Devils Canyon
include Devil, Fog (RM 179.2), and Tsusena (RM 181.3) creeks. Portage Creek enters the
Susitna River below Devils Canyon. As the Susitna River curves south past Gold Creek (RM
136.8), about 12 miles downstream from Devils Canyon, its gradient gradually decreases.
Within Devils Canyon there are three partial barriers to upstream migration by anadromous fish.
Chinook salmon are known to pass the two lower barriers on a regular basis; however passage
over the third barrier located downstream of Devil Creek appears to occur only under narrow
hydraulic conditions. During 2012 radio-tagged Chinook salmon passed the third barrier during
a short period when flows were approximately 16,000 cubic feet per second (cfs; AEA
unpublished data). Other anadromous salmon in the Susitna drainage (chum salmon, sockeye
salmon, pink salmon, and coho salmon) have not been observed to pass any of the three partial
barriers.
The lower Middle River generally has a single main channel, with some segments containing one
or two secondary side channels, complex islands, side sloughs, and upland sloughs. Mainstem
habitat is typically characterized by high water velocities and well armored streambeds.
Mainstem substrates generally consist of boulder and cobble size materials with interstitial
spaces filled with a grout-like mixture of small gravels and glacial sands while more protected
side channels and side slough often include smaller substrate (Estes and Schmidt 1983).
2.3. Lower River
From the confluences with the Chulitna and Talkeetna rivers, the Susitna River flows south for
about 97 miles until it empties into Cook Inlet near Anchorage, approximately 318 miles from its
source. Channel morphology in the Lower River is influenced by the large volume of sediment
delivered from the Chulitna River and lower gradient than the lower Middle River. The Yentna
River, which accounts for about half of the sockeye salmon returns to the Susitna Basin, joins the
Susitna River at RM 28 (Jennings 1985). Located within a wide gravel floodplain, the Lower
River segment includes braided channel sections as well as areas with a main channel and
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multiple secondary channels. Downstream of RM 19.0, the river divides into two main channels
with the majority of flow following the east channel (Ashton and Klinger-Kingsley 1985).
During low flow periods large gravel bars are present in the Lower River.
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3. OVERVIEW OF EXISTING STUDIES
Historically, fish studies in the Susitna River basin were initiated in the 1950s. During these
studies, fish surveys were conducted in nine tributaries upstream and downstream of Devils
Canyon. Tributaries surveyed included: Indian River, Jack Long Creek, Portage Creek,
Deadman Creek, Watana Creek, Jay Creek, Kosina Creek, Goose Creek, and the Oshetna River
(USFWS 1957, 1959a, 1959b). Fish observations included the following: adult Chinook salmon,
chum salmon, pink salmon, coho salmon, Arctic grayling and rainbow trout in the Indian River;
grayling and rainbow trout in Jack Long Creek; four pink salmon carcasses, but no salmon
spawning grounds, in Jack Long Creek; Chinook salmon, chum salmon, pink salmon, coho
salmon, and Arctic grayling in Portage Creek; Arctic grayling, burbot, slimy sculpin, round
whitefish, humpback whitefish, and longnose sucker in Watana Creek and the mouths of Watana
and Deadman creeks; no salmon observed in Jay Creek; and abundant Arctic grayling in Kosina
Creek and the Oshetna River.
However, more intensive studies were conducted in the 1980s. An overview of these studies is
provided herein. Detailed results specific to species and life stages are provided in Sections 5
through 8. In addition, results related to other study components, such as barriers, access
corridors, and aquatic productivity, are provided in Sections 9 through 11.
3.1. 1980 Era Aquatic Studies Program
A five- year, two-phase program for assessing the feasibility of a two-dam hydroelectric project
on the Susitna River was initiated by APA in 1979 with Acres American Inc. (Acres) as the
prime contractor for implementing the program (Estes and Bingham 1982). Acres subcontracted
to ADF&G to describe the fishery and aquatic habitat resources of the Susitna River. The
ADF&G Aquatic Studies Program began in November 1980 and had three components: Adult
Anadromous Fish Studies (AA), Resident and Juvenile Anadromous Fish Studies (RJ), and
Aquatic Habitat and Instream Flow Studies (AH). In addition to work completed by ADF&G,
the AH component was supported by work conducted by Trihey and Associates. The objectives
for each of the components were (Schmidt and Bingham 1983):
AA - determine the seasonal distribution and relative abundance of adult anadromous fish
populations produced within the study area;
RJ - determine the seasonal distribution and relative abundance of selected resident and
juvenile anadromous fish populations within the study area; and
AH - characterize the seasonal habitat requirements of selected anadromous and resident
fish species within the study area and the relationship between the availability of these
habitat conditions and the mainstem discharge of the Susitna River.
Field studies were conducted monthly from November 1980 through October 1985, except for
periods of freeze-up and ice-off, and resulted in more than 80 volumes of annual reports (Table
3.1-1). A wide variety of fisheries field and habitat modeling studies occurred over the 5-year
period when most studies were completed (Table 3.1-2). In general, RJ and AH studies were
broad-based during 1981 and 1982 with the widest geographic scale and sampling methods. As
the Aquatic Studies Program progressed, studies became more focused on acquiring specific
information needs for habitat modeling and acquisition of specific biological data. In addition,
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the results of 1981 and 1982 sampling led to conclusions regarding fish distribution and
hypotheses about habitat utilization that led to more intensive sampling at fewer sites with
known fish use. Fewer crews limited their sampling techniques to those that had demonstrated
effective fish capture success previously. These sampling techniques included fishwheels and
incline plane traps to understand migratory timing, minnow traps, trotlines, beach seines, boat
electrofishing, and backpack electrofishing to understand fish distribution and habitat utilization,
and radio-tracking to understand adult fish behavior. Sampling sites for RJ studies and AH
studies were frequently the same during the 1983 and 1984 field seasons.
A major objective of the 1980s Aquatic Studies Program was to understand the seasonal fish use
of six mainstem (macro-) habitat types. The six mainstem habitat types consisted of mainstem
(main channel), side channel, side slough, upland slough, tributaries, and tributary mouths
(Figure 3.1-1; ADF&G 1984). The distribution and frequency of these habitats varied
longitudinally within the river depending in large part on its confinement by adjoining floodplain
areas, size, and gradient. The habitat types are depicted graphically and were described with
respect to mainstem flow influence by ADF&G in the Susitna Hydroelectric Aquatic Studies
Procedures Manual (1984) as follows, with additional clarification added herein where
considered appropriate.
Main Channel Habitat was defined as those portions of the Susitna River that normally
convey streamflow throughout the year. Both single and multiple channel reaches were
included in this habitat category. Groundwater and tributary inflow appeared to be
inconsequential contributors to the overall characteristics of mainstem habitat. Mainstem
habitat was typically characterized by high water velocities and well-armored
streambeds. Substrates generally consisted of boulder and cobble size materials with
interstitial spaces filled with a grout-like mixture of small gravels and glacial sands.
Suspended sediment concentrations and turbidity were high during summer due to the
influence of glacial melt-water. Streamflows receded in early fall and the mainstem
cleared appreciably in October. An ice cover formed on the river in late November or
December.
Side Channel Habitat consisted of those portions of the Susitna River that normally
convey streamflow during the open water season but became appreciably dewatered
during periods of low flow. Side channel habitat existed either in well-defined overflow
channels, or in poorly defined water courses flowing through partially submerged gravel
bars and islands along the margins of the mainstem river. Side channel streambed
elevations were typically lower than the mean monthly water surface elevations of the
mainstem Susitna River observed during June, July and August. Side channel habitats
were characterized by shallower depths, lower velocities and smaller streambed materials
than the adjacent habitat of the mainstem river.
“Side” Slough Habitat was located in spring fed overflow channels between the edge of
the floodplain and the mainstem and side channels of the Susitna River and was usually
separated from the mainstem and side channels by well vegetated bars. An exposed
alluvial berm often separated the head of the slough from mainstem or side channel
flows. The controlling streambed/streambank elevations at the upstream end of the side
sloughs were slightly less than the water surface elevations of the mean monthly flows of
the mainstem Susitna River observed for June, July, and August. At intermediate and
low-flow periods, the side sloughs conveyed clear water from small tributaries and/or
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upwelling groundwater (ADF&G 1981c. 1982b). These clear water inflows were
essential contributors to the existence of this habitat type. The water surface elevation of
the Susitna River generally caused a backwater to extend well up into the slough from its
lower end (ADF&G 1981c, 1982b). Even though this substantial backwater existed, the
sloughs functioned hydraulically very much like small stream systems and several
hundred feet of the slough channel often conveyed water independent of mainstem
backwater effects. At high flows, the water surface elevation of the mainstem river was
sufficient to overtop the upper end of the slough (ADF&G 1981, 1982b). Surface water
temperatures in the side sloughs during summer months were principally a function of air
temperature, solar radiation, and the temperature of the local runoff.
“Upland” Slough Habitat differed from the side slough habitat in that the upstream end
of the slough was not interconnected with the surface waters of the mainstem Susitna
River or its side channels at less than bankfull flows. The upstream end might have been
vegetated with mature trees, although a morphologic signature of a converging inlet and
gravel levee closure was still discernible. These sloughs were characterized by the
presence of beaver dams and an accumulation of silt substrate that resulted from the
absence of mainstem scouring flows. They were not truly “upland” in the geomorphic
sense, but the use of this nomenclature in the 1980s studies reflected the observation that
the understanding of floodplain and channel forming processes was in the early stage in
fisheries, where some variation in interpretation existed over what constituted a
floodplain versus an upland terrace (e.g., see Williams 1978). Essentially, the main
distinguishing characteristic between a “side” slough and an “upland” slough was the
level of high flow at which each was engaged.
Tributary Habitat consisted of the full complement of hydraulic and morphologic
conditions that occurred in the tributaries. Their seasonal streamflow, sediment, and
thermal regimes reflected the integration of the hydrology, geology, and climate of the
tributary drainage. The physical attributes of tributary habitat were not dependent on
mainstem conditions.
Tributary Mouth Habitat extended from the uppermost point in the tributary influenced
by mainstem Susitna River or slough backwater effects to the downstream extent of the
tributary plume which often extended into the mainstem Susitna River or slough
(ADF&G 1981c, 1982b).
Beginning in the 1983 open water studies, a fundamental change was made in how side sloughs
and side channels were identified (Dugan et al. 1984). During 1981 and 1982, side sloughs and
side channels were distinguished primarily on their morphology. Side sloughs included an
unvegetated berm at the head of the slough and were rarely overtopped. In contrast, a side
channel conveyed mainstream flow during most of the year. During 1983 and following years, if
a berm was overtopped and a channel conveyed mainstem flows it was characterized as a side
channel. If the berm was not overtopped it was characterized as a side slough. Consequently,
during the latter years of the 1980s Aquatic Studies Program an area may be characterized as a
side channel during periods of high flows and a side slough during periods of lower flows.
Another major objective of the 1980s Aquatic Studies Program was to gain an understanding of
the escapement and distribution of adult salmon. These efforts were primarily based upon three
sampling techniques:
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Fishwheels and sonar
Spawning surveys
Radio tracking
Sampling at the fishwheels included fish length measurements, attachment of floy tags, and
removal of scales for aging fish. Floy spaghetti tags or Petersen disc tags were used to study fish
movements and to estimate escapement using Peterson estimation techniques. Adult periodicity
information is primarily available from fishwheels and Bendix sonar stationed at a number of
locations in the mainstem Susitna River and in the Yentna River (Table 3.1-3). Stations were
generally deployed in early- to mid-June and fished through early- to mid-August. Spawning
surveys occurred annually by foot, raft, airplane, or helicopter. The surveys included index
streams/reaches that were checked once or twice on an annual basis at the time of peak
spawning. Additional surveys were also conducted specifically for the Aquatic Studies Program
and varied in the level of intensity and location each year. In general, between 1981 and 1985,
all side channels, sloughs and tributaries that are in the reach from Talkeetna to Devils Canyon
and that were known to have spawning fish present were surveyed on a weekly basis during the
salmon spawning season. In 1981 and 1982, radiotracking was used to identify spawning and
holding locations and better understand migration rates (ADF&G 1981, ADFG 1982). However,
the number of fish tracked within a species was 18 or fewer fish.
Information on the distribution and abundance of juvenile and resident fish was also important to
the Aquatics Study Program. Sampling for juvenile and resident fishes from November 1980
through mid October1981 included a wide range of sites and sampling techniques (Figure 3.1-
2Figure). By June of 1981, the Aquatic Studies Program had settled on 39 areas, which they
termed “habitat locations,” that were the focus of sampling during the open water period
(Delaney et al. 1981). During the winter of 1980 to 1981, 29 of the habitat locations were
sampled, plus an addition 48 “selected fish habitat sites” that were described as exploratory
sampling. An understanding of habitat utilization by juvenile anadromous and resident fish was
developed as part of more focused studies during 1982, 1983, and 1984. During 1982, 17 sites
referred to as Designated Fish Habitat (DFH) sites were surveyed twice monthly from June
through September during the open water season (Estes and Schmidt 1983). Twelve sites were
located in the Middle River (Whiskers Creek and Slough to Portage Creek Mouth) and five were
located in the Lower River (Goose Creek and Side Channel to Birch Creek and Slough; Table
3.1-4; Figure 3.1-3; Figure 3.1-4).
Habitat zones were delineated within each DFH site based upon the influence of mainstem flow,
tributary flow, and water velocity (Table 3.1-5; Figure 3.1-5). Because the zones were based
upon flow characteristics, the size of the zones may have varied from survey to survey. As part
of the statistical analysis the nine zones were aggregated into Hydraulic and Water Source Zones
(Table 3.1-6). In addition to statistical tests to determine associations between fish species catch
per unit effort and aggregate hydraulic and water source zones, tests were also run to examine
correlations between catch per unit effort and habitat variables including water temperature,
turbidity, and velocity (Schmidt and Bingham (1983, Appendix E). A large number of sites (275
mainstem sites and 55 tributary and other slough sites) called Selected Fish Habitat (SFH) sites
were also sampled in 1982, but these sites were usually sampled less frequently (1 to 3 times)
and more opportunistically than DFH sites (Figure 3.1-6).
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During 1983 and 1984, studies were focused on obtaining information needed for developing
instream flow models under the AH component and sampling was coupled with obtaining
additional distribution and abundance information desired for the AJ component (Schmidt et al.
1984, Suchanek et al. 1985). The instream flow models include Resident Juvenile Habitat
(RJHAB) and Instream Flow Incremental Methology (IFIM) models The 1983 open water
studies included 35 study sites (called Juvenile Anadromous Habitat Study or JAHS sites) in the
lower Middle River while the 1984 studies included 20 sites in the Lower River (Table 3.1-7).
Macro habitat types included in the study were tributary, upland slough, side slough, and
mainstem side channel. Rationale for sites selected for study included (Dugan et al. 1984):
1. Sites where relatively large numbers of spawning adult salmon were recorded in 1982
(ADFG 1982),
2. Sites where concentrations of rearing juvenile salmon were observed or collected in 1981
and 1982, and
3. Sites representing macrohabitat types associated with the Susitna River that are affected
by changes in mainstem flow.
In addition to the combined AH and AJ sampling efforts, studies were implemented to better
understand juvenile salmon outmigration and growth (Roth et al. 1984, Roth and Stratton 1985),
resident fish distributin and abundance (Sundet and Pechek 1985), river productivity (Wilson
1985, Nieuwenhuyse 1985), and invertebrate food sources for Chinook salmon (Hansen and
Richards 1985).
The 1983 and 1984 JAHS sites were sampled in a systematic fashion within grids delineated at
each site (Dugan et al. 1984, Suchanek et al. 1985). As described in Dugan et al. (1984) and
depicted in Figure 3.1-7:
“Each of the study sites was divided into one or more grids. Grids were located
to keep water quality (temperature, turbidity) within the site as uniform as
possible and to encompass a variety of depth, velocity, cover, and substrate types.
Each grid consisted of a series of transects which intersected the channels of the
study sites at right angles. There were one to three cells (6 ft. in width by 30 ft. in
length = 300 sq. ft.) at every transect within the grid. An attempt was made to
confine uniform habitat within each cell. Fish were usually sampled from a
minimum of seven cells within each grid at each site.
The cells were selected to represent the complete range of habitat types available
within the grid. Fish density was estimated by electrofishing or beach seining the
entire cell, attempting to capture all fish. Catch per unit effort (CPUE) was
defined as the catch (number of fish) per cell.”
The analysis utilized the percent distribution of each salmon species among the four
macrohabitat types sampled as the evaluation metric. Analysis of variance (ANOVA) techniques
were used to discern factors affecting habitat use by the differen juvenile salmon species. In
addition to site and sampling period, the factors collected in each cell following fish sampling
included mean water depth, mean water velocity, mean percent cover, water temperature, and
turbidity. Depth, velocity, and cover measures were averaged over the entire site because the
cells were not randomly distributed.
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During winter of 1984-1985 JH studies included a Chinook salmon and coho salmon habitat
study (Stratton 1986) and resident fish study (Sundet 1986). Stratton (1986) sampled four
locations in the lower Middle River (Indian River, Slough 9A, Slough 10, and Slough 22) using
minnow traps and backpack electrofishing at an interval of ten to fifteen days from October
through April. Captured Chinook salmon and coho salmon were marked with a cold brand
identifying the location and time period of capture. For the winter-time resident fish study
(Sundet 1986), 23 rainbow trout, fourteen burbot, and five Arctic grayling were radio-tagged in
the lower and middle Susitna River between early September and October. An additional 15
rainbow trout radio-tagged during the spring were also tracked. Tracking surveys occurred
primarily by airplane or helicopter, but occassionally included snow machines. Burbot spawning
was also studied by deployment of trotlines in areas near where radio-tagged fish were located.
The open water season of 1985 included a study of juvenile salmon migration and growth (Roth
et al. 1986) and continued monitoring of adult salmon escapement and spawning habitat use
(Thompson et al. 1986). Outmigration was studied by deployment of fixed incline plane traps
near Flathorn Station (RMS 22.4 and 24.6) and at Talkeetna Station (RM 103) and deployment
of a mobile trap that sampled along a cross sectional transect at RM 25.4. Coded wire tags were
embedded into juvenile chum salmon and sockeye salmon collected at selected sites upstream of
Talkeetna. Chinook salmon and coho salmon were cold branded at sites in the Indian Creek,
Portage Creek, Sice Channel 10A, and Slough 15.
A number of instream flow modeling studies were conducted during 1984, 1985, and 1986 based
upon the field studies conducted in 1983 and 1984. The details and results of these instream
flow studies are described in an Instream Flow Technical Memorandum (R2 Resource
Consultants 2013).
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4. HABITAT DISTRIBUTION
Most of the habitat characterization in the Susitna River has occurred in the Middle and Lower
River with limited data collection in the Upper River. Habitat characterization methods have
varied within each of these river segments but were most similar in Middle and Lower River
studies conducted in the 1980s. These studies provide the majority of the historic habitat data
presented herein. In addition, tributary habitats upstream and downstream of Devils Canyon were
characterized during fish studies in the 1950s, and in the early 2000s, some habitat data was also
collected in Upper River tributaries as part of the Alaska Freshwater Fish Inventory (AFFI)
program (Buckwalter 2011a, Buckwalter 2011b). However, the scale of these data collection
efforts limits the utility of the data for evaluating fish-habitat relationships and potential changes
in fish habitat use as a result of hydropower facility development and operation.
Habitat was characterized and mapped in a number of different ways during the 1980s in addition
to the macrohabitat types described in Section 3.1. Steward and Trihey (1984) also defined
unique categories of river habitat based on clear or turbid water conditions under specific flow
levels in combination with the presence or absence of open water leads during winter and
hydrologic zones within DFH sites were assigned as part of sampling during 1982 (Estes and
Schmidt 1983, Schmidt et al. 1983). The macrohabitat categories used in the lower Middle
Susitna River were focused on main channel, side-channel, and side-slough habitats in intensively
studied areas in an attempt to scale the information up to the entire Middle Susitna River Reach
for simulating the relationship between habitat and flow (Aaserude et al. 1985, Klinger-Kingsley
et al. 1985). Ashton and Klinger-Kingsley (1985) examined how channel morphology and aquatic
habitat in the lower river, as measured by surface area, were affected by changes in flow;
however, aquatic habitat suitability to fish species was not considered.
4.1. Susitna River Upstream of Devils Canyon
During the 1950s fish studies, tributaries upstream of Devils Canyon that were surveyed
included: Deadman, Watana, Jay, Kosina, and Goose creeks, as well as the Oshetna River
(USFWS 1957, 1959a, 1959b). Deadman Creek was described as a clear stream 30 miles long
with numerous pools and rock and boulder substrate (USFWS 1959a). Water temperatures were
53.5°F (11.9°C) and 54.0°F (12.2°C) on June 21 and June 30, 1957, respectively, and aquatic
insects were observed to be abundant. Watana Creek was described as a green-tinged clearwater
stream 20 miles long, 40 feet wide, and 1 to 2 feet deep. Discharge was measured as 150 to 160
cfs at the time of the survey. Substrate was considered suitable for salmon, and occasional deep
pools were present. Mean water temperature measured during the early morning between June
20 and August 30 was 52°F (11.1°C) and ranged from 49 to 69°F (9.4 to 20.6°C). Jay Creek was
described as a yellow and turbid low gradient stream for two miles, then substantially steeper
(USFWS 1957). Kosina Creek was described as slightly yellow-tinged clearwater stream 35
miles in length with a steep gradient (USFWS 1959a). Habitat was primarily riffles with steep
banks and substrate of rock and boulders. Water temperature was measured as 63°F (17.2°C).
Goose Creek was described as a clearwater stream having riffle-pool habitat with substrate
consisting of gravel, rubble, and boulders (USFWS 1959b). Water temperature was 52°F
(11.1°C) at 1 pm, July 31. The creek had relatively high water (200 cfs) during the survey due to
heavy precipitation with depths averaging two feet and width averaging 25 feet. The Oshetna
River was described as a fast clearwater stream 100 feet wide and four feet deep with few pools.
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Substrate was gravel, rubble, and boulders. Water temperature was 48°F (8.9°C) at 7:30 am,
July 31, and an abundance of caddis flies were observed.
Sautner and Stratton (1983) surveyed eleven streams upstream of the proposed Devils Canyon
Dam: Cheechako Creek, Chinook salmon Creek, Devils Creek, Fog Creek, Tsusena Creek,
Deadman Creek, Watana Creek, Kosina Creek, Jay Creek, Goose Creek, and Oshetna River
(Figure 4.1-1). Discharge measurements were taken during mid-August and mid-September at
six of the streams (Figure 4.1-2). Habitat characteristics of these tributaries from Sautner and
Stratton (1983) are summarized in Table 4.1-1. At the time, salmon spawning was thought to
extend as far as Chinook salmon Creek and the best spawning habitat was considered to be the
clearwater plume downstream of Cheechako Creek and very little of the creeks upstream of the
mouths were considered suitable for salmon spawning because of high velocities (Sautner and
Stratton (1983). Sautner and Stratton (1983) frequently observed sand as a component to the
sediment load from tributaries draining from the north of the mainstem Susitna River. Cobble
and rubble was observed to be highly embedded within sand in lower velocity habitat types
(Figure 4.1-3).
4.2. Middle Susitna River Downstream of Devils Canyon
During the 1980s study efforts, habitat characterization and mapping in the mainstem of the lower
Middle Susitna River segment was conducted at the macrohabitat scale (Klinger-Kinsley et al.
1985). The mapping effort by Klinger-Kinsley et al. (1985) was part of a process developed by
Trihey and Associates (Steward and Trihey 1984, Aaserude et al. 1985) for extrapolating the
results of instream modeling at selected representative locations to a larger unmodeled portion of
the river. The mainstem macrohabitat types were representative of distinct functional hydrology
and channel morphology were identified. Under this system, the lower Middle Susitna River was
classified into seven mainstem macrohabitat types: mainstem channel, side channel, side slough,
upland slough, tributary mouth, tributary, and lakes, defined by source water and hydrologic
connectivity (Trihey 1982, Estes and Schmidt 1983). Detailed descriptions of these macrohabitat
types are provided in Section 3.1. Areas delineated by Klinger-Kingsley et al. (1985) included
mainstem, side channel, and side slough aquatic habitat plus gravel bars and vegetated bars.
Aaserude et al. (1985) reported that ten sets of aerial photography were available for habitat
characterization (Table 4.2-1). For determination of the amount of surface area for the
macrohabitat types, eight of the aerial photo sets were used: 23,000 cfs, 18,00 cfs, 16,000 cfs,
12,500 cfs, 10,600 cfs, 7,400 cfs, and 5,100 cfs (Klinger-Kinsley et al. 1985). Photos at lowest
flow level and at 9,000 cfs were not used because of the presence of ice cover. No explanation
was provided for not using photos at the 26,900 cfs flow level. The relative amount of the
different habitat types delineated by Klinger-Kingsley et al. (1985) are depicted in Figure 4.2-1
and demonstrate the increase in mainstem and side channel habitat area as flows increase with a
concurrent decline in the surface area of side slough habitat, gravel bars, and vegetated bars.
The characterization of tributary habitat downstream of Devils Canyon was available from data
collected in 1956 and was limited to the Indian River, Jack Long Creek, and Portage Creek
(USFWS 1957). Indian River was described as a clear and fast stream 25 feet wide and 3.5 feet
deep. The lower 1.5 miles were considered too steep for salmon spawning, although suitable
spawning habitats were observed further upstream. Jack Long Creek was described as steep with
clear, but slightly yellow tinged water. Portage Creek was described as a blue-tinged clearwater
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stream larger than Indian River with a width of 40 to 60 feet and depth of 5 to 8 feet. Many deep
pools were observed.
4.3. Lower Susitna River
Similar to the middle river for the macrohabitat types, Ashton and Klinger-Kingsley (1985)
estimated wetted surface area from aerial photos over a range of mainstem river flows for
channel types and macrohabitat types within selected representative areas of the lower river.
Five sets of aerial photos taken at mainstem discharge levels of 13,900 to 75,000 cfs (Sunshine
gage) were evaluated. Five river segments were delineated based upon river morphology and
hydrology:
Segment I – RM 98.5 to RM 78.0
Segment II – RM 78.0 to RM 51.0
Segment III – RM 51.0 to RM 42.5
Segment IV – RM 42.5 to RM 28.5
Segment V – RM 28.5 to RM 0.0
Channel classifications were delineated in Segment I to Segment IV. Segment V is influenced by
tidal flow and the Yentna River discharge and was not delineated. Because of geomorphic
differences in the river form, the lower river classification system was different than the middle
river (Ashton and Klinger-Kingsley 1985). Two main channel classifications were delineated on
aerial photos: Mainstem Channel and Side Channel Complexes. Each of these had two or three
subclassifications:
Mainstem Channel - That portion of the river floodplain between the vegetated
boundaries, including the wide gravel floodplain and isolated vegetated islands in mid-
channel
Mainstem River – the thalweg channel and main subchannels
Alluvial Island Complexes – Areas of broad gravel islands with numerous subchannels
which dewater as flow decreases
Side Channel Complexes – One or more channels flowing among a group of vegetated
islands. These complexes are usually located along the edge of the mainstem river but, in
areas such as the Delta Islands, may occur in the middle of the river.
Major Side Channels are overtopped at mainstem flows of 13,900 cfs and lower. They
tend to be, but are not limited to, the outside-most channel of a complex, closest to the
edge of the floodplain. These channels may collect groundwater seepage and tributary
flow.
Intermediate Side Channels – These dewater at their upstream berm in the mainstem flow
range of 13,900 cfs to 59,000 cfs. After their upstream berm dewaters, some intermediate
channels maintain turbid water to mainstem flow of 21,100 cfs or less, while other
contain clearwater from groundwater and/or surface water inflow. Other intermediate
side channels dewater the complete length of the channel before the mainstem flow
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decreases to 21,000 cfs. Intermediate side channels may be extensions of tributaries once
their upper berms dewater.
Minor Side Channels – These side channels dewater at their upstream berm at mainstem
flows of 59,100 cfs and higher. These channels tend to be dewatered the complete length
of the channel at mainstem flows of 36,600 cfs.
Ashton and Klinger Kingsley (1985) found the rate of change in the surface area of mainstem
channels was relatively steady over the mainstem discharge levels evaluated (Figure 4.3-1). In
contrast, the surface area of side channel complexes changed more rapidly at mainstem flows
between 13,900 cfs and 21,000 cfs. Ashton and Klinger-Kingsley (1985) also selected eight
representative areas for delineation of 8 macrohabitat types: mainstem, primary side channel,
secondary side channel, turbid backwater, clearwater, side slough, tributary mouth, and tributary
(Table 4.3-1). However, because of difficulty in seeing the water’s edge in the aerial photos they
did not delineate Birch Creek Slough. Definitions of macrohabitat types were slightly different
than those used for the middle river:
Mainstem – Habitats consist of the thalweg channel, major subchannels and alluvial
island complexes.
Primary Side Channel – Habitats are those channels which normally convey streamflow
throughout the entire year. They are characterized by turbid glacial water, high
velocities, and few mid-channel gravel bars.
Secondary Side Channels – These habitats also have turbid water, but exhibit
characteristics of middle river side channels. These habitats include mid-channel gravel
bars and riffles or water surface features that indicate slower-moving, shallower water.
Turbid Backwater – These habitats are nonbreached channels containing turbid water.
They have non-vegetated upper thalwegs that are overtopped during periods of moderate
to high mainstem discharge. They represent a transitional habitat type between breached
secondary side channel habitats and nonbreached clearwater or side slough habitats.
Clearwater – These habitats are nonbreached channels containing clear water that
dewater completely at a mainstem discharge of 13,000 cfs or higher. They have non-
vegetated upper thalwegs that are overtopped during periods of moderate to high
mainstem discharge. Groundwater and local surface runoff appear to supply water these
areas at mainstem flows above 13,900 cfs.
Side Slough - These habitats contain clear water. Upwelling and local surface runoff
appear to supply sufficient clear water to these areas to maintain wetted areas at a
mainstem discharge of 13,000 cfs. Side sloughs also have non-vegetated upper thalwegs
that are overtopped at moderate to high mainstem discharges.
Tributary Mouth – These habitats are clear water habitats that exist between the
downstream extent of a clear water plume and upstream into the tributary to the upper
extent of the backwater influence. The surface area depends on the discharge of both the
tributary and mainstem.
Tributary – This habitat exists upstream of the tributary mouth habitat and was measured
to the extent of the aerial photo. Tributary habitat may increase dramatically when the
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tributary flows into a nonbreached side channel and the clear tributary flows through the
side channel to join the Susitna River.
In addition to these aquatic habitat types, the area occupied by gravel bars was also estimated
from the aerial photos (Ashton and Klinger-Kingsley 1985). The proportion (Figure 4.3-2) and
area (Figure 4.3-3) of each of these habitats is graphically depicted for five of the seven sites
delineated. At flows of 21,000 cfs and lower, gravel bars represent more than half of the surface
area at the sites. Conversely, mainstem and secondary side channel habitat types account for
increasing amounts of the surface area at the sites as flows increase. Side sloughs, tributary
mouths, tributaries, and turbid backwaters represent relatively small amounts of area at each of
the sites, both individually and in total.
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5. ADULT SALMON
5.1. Chinook Salmon
5.1.1. Abundance/Escapement
Of the five salmon species returning to the Susitna River, Chinook salmon have had the fewest
number of fish but have been the most important sport fish (Jennings 1985). Long term
escapement trend data from 1974 to 2009 are available for a number of index streams in the
Susitna River Basin monitored by ADF&G, but between stream comparisons are unreliable
because of different survey methods (weirs, foot, or aerial; Fair et al. 2010). Most index streams
are tributaries to the mainstem in the Lower River or tributaries in the Chulitna and Talkeetna
subbasins and surveyed by aerial methods (Fair et al. 2010). The Deshka River (RM 40.6) has
the highest escapement of all tributaries with a median of 35,548 fish (Figure 5.1-1). ADF&G
installed a counting weir in the Deshka River prior to the 1995 season to improve the accuracy of
salmon escapement counts (Fair et al. 2010). All other index streams generally have fewer than
5,000 fish spawning during peak surveys (Figure 5.1-2).
Total peak counts of Chinook salmon spawning in Middle River tributaries between 1981 and
1985 ranged from 1,121 to 7,180 fish with a median of 4,179 fish (Jennings 1985, Thompson et
al. 1986). Generally over 90 percent of the Chinook salmon returns to the Middle Susitna River
have spawned in Indian or Portage creeks. Peak spawner counts from 1976 to 1984 ranged from
114 to 1,456 fish (median 479.5 fish) in Indian Creek and 140 to 5,446 fish (median 680.5 fish)
in Portage Creek (Jennings 1985).
ADF&G used mark recapture techniques to estimate escapement to fishwheel stations during the
early 1980s (Figure 5.1-3). From 1982 to 1985, total escapement (point estimates) to Sunshine
Station ranged from 52,900 to 185,700 fish with a median 103,614 (Barrett et al. 1983, Barrett et
al. 1984, Barrett et al. 1985, Thompson et al. 1986). Escapement to Talkeetna Station ranged
from 10,900 to 24,591 fish (median 14,400 fish), but was considered an overestimate because
many Chinook salmon tagged at Talkeetna Station have been found to spawn in tributaries
downstream of Talkeetna Station (Jennings 1985). The large difference between these two
stations, especially considering the overestimate at Talkeetna, reflects the large number of fish
that returned to tributaries downstream of the Three Rivers Confluence, as well as to the Chulitna
and Talkeetna rivers.
Within the Susitna River drainage, ADF&G has established escapement goals on the Chulitna
and Deshka rivers, and on Chunilna, Montana, Willow, and Little Willow creeks. Aside from
the Deshka River weir, all of these goals are based on counts indexed with a single annual aerial
survey. Chinook salmon escapements were also counted at a floating weir operated at Willow
Creek from 2000 through 2002. Counts were used as part of a coded wire tag recovery project,
and were not expanded to the entire Susitna River drainage (Yanusz 2013, pers. comm.).
Declines in returns of Chinook salmon have prompted the Alaska Board of Fisheries to list
several Susitna River tributaries as a Stock of Concern. These include Alexander Creek as
Management Concern listed in 2011 and Willow and Goose Creeks as Yield Concern in 2011.
Low returns to the Deshka River in 2007 through 2009 have also prompted concern and in 2012
low returns resulted in an early closure to the sport fishery.
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5.1.2. Distribution
Based upon observations of juveniles, Chinook salmon are distributed in the Susitna River up to
the Oshetna River (RM 225; Table 5.1-1; Buckwalter 2011). Buckwalter also observed juvenile
Chinook salmon in Fog Creek, Kosina Creek, and Oshetna River during 2003 and a Fog Creek
tributary during 2011. During 1984, two spawning Chinook salmon were observed in Fog Creek
(RM 176.7; Table 5.1-2; Barrett 1985). More recently, Buckwalter (2011) observed adult
Chinook salmon in Fog Creek and Tsusena Creek (RM181.3) during 2003 and in Kosina Creek
(RM 201) during 2011. In addition, 16 adult Chinook salmon were observed in Kosina Creek
during 2012 (AEA unpublished data). During 2012, ADF&G began a mark-recapture study to
identify the spawning distribution of Chinook salmon in the Susitna River drainage (Cleary et al.
in prep).
A series of three partial velocity barriers are present in Devils Canyon that restricts access to
upstream habitat. Chinook salmon are the only known anadromous salmon that can pass all
three barriers (AEA unpublished data). The lower two barriers appear to be passable by Chinook
salmon at a relatively broad range of flows. Data from 2012 indicated that the upper barrier,
located downstream of Devil Creek, can be passed at flows of approximately 16,000 cfs as
measured at the Gold Creek gage.
Chinook salmon spawn exclusively in tributary streams (Thompson et al. 1986, Barrett 1985,
Barrett 1984, Barrett 1983). Consequently, the mainstem Susitna River primarily provides a
migration corridor and holding habitat for adult Chinook salmon. Apportionment of Chinook
salmon among the major Susitna River subbasins based on peak spawning surveys has been
somewhat confounded by inconsistent surveys, in part because poor visibility and partly due to
annual differences in surveying priorities. Nevertheless, major patterns in the distribution of
Chinook salmon spawning during the late 1970s and early 1980s are discernible based upon data
summarized in Jennings (1985). Tributaries to the Lower Susitna River tend to account for 50
percent or more of the Chinook salmon spawning (Figure 5.1-4). Important spawning tributaries
in the Lower River are the Deshka River and Alexander Creek. The Yentna River and
Talkeetna/Chulitna subbasins typically account for about 20 percent and 15 percent, respectively.
The Middle River tributaries typically account for about 5 percent of the Chinook salmon
spawning in the Susitna River. Considering only the Middle River, Portage Creek and Indian
River account for nearly all Chinook salmon spawning (Figure 5.1-5). Fourth of July Creek and
Whiskers Creek account for minor amounts of spawning, generally with no more than about 2.5
percent of the spawning in the Middle River.
5.1.3. Age of Return
On average, Chinook salmon return to the Susitna River at roughly similar proportions for Age 3
(21.0 percent), Age 4 (24.9 percent), Age 5 (23.7 percent), and Age 6 (27.4 percent; Figure 5.1-
6; ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986). On
average, about 2.7 percent of the returns are Age 7 fish. Variability in the age structure of
Chinook salmon is influenced by sampling error due to the location and hydraulic conditions at a
particular fishwheel’s location (Thompson et al. 1986) as well as interannual differences in age
class strength. Fishwheels located in areas with lower water velocities tend to catch fewer large
fish, thus the age structures could be biased towards higher proportions of Age 3 and Age 4 fish.
During 1985 the average length of Chinook salmon was 508 mm for fish captured at the Flathorn
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Station, 778 mm at the Sunshine Station, and 730 mm at the Curry Station (Thompson et al.
1986).
5.1.4. Periodicity
Adult periodicity information was primarily available from fishwheels and Bendix sonar
stationed at a number of locations in the mainstem Susitna River and in the Yentna River (Table
3.1-3). Adult Chinook salmon begin their upstream migration in late-May to early June
(Jennings 1985, ADF&G 1984; Figure 5.1-7). Although a few Chinook salmon passed Susitna
Station (RM 26.7) as late as mid-August, nearly all Chinook salmon (95 percent) passed the
station by the first week of July (ADF&G 1981, Jennings 1985). Peak run timing was generally
later at Talkeetna Station (RM 103) compared to Sunshine Station. However, peak run timing at
Curry Station appeared to be similar to, or earlier than, Talkeetna Station. This indicates that
upriver fish (i.e., Chinook salmon bound primarily for Indian and Portage creeks) enter and
migrate during the early portion of the overall Susitna migration period. Based on 1980s
surveys, Chinook salmon spawning begins in mid-July and is finished by the end of August
(Barrett 1985, Jennings 1985). Peak spawning was during the last week of July and first week of
August (Jennings 1985). Run timing (decreased fishwheel catch rates) may have been affected
by high flow levels; however, this pattern was not consistent across all years (Jennings 1985).
5.1.5. Holding and Spawning Habitat Utilization
Little information was available describing holding habitat used by Chinook salmon. Tracking
of a few radio-tagged Chinook salmon in 1981 (16 fish) and 1982 (16 fish) indicated that the
Three Rivers Confluence and tributary mouths were frequently used for holding and milling
(Schmidt and Bingham 1983). Chinook salmon radio-tagged at Talkeetna Station during 1981
frequently moved downstream to the Three Rivers area and remained in that area for up to two
weeks (ADF&G 1981). In contrast, four of eight Chinook salmon radio-tagged at Curry station
migrated upstream shortly after release. Similar behavior patterns were observed in 1982
(ADF&G 1982c). Based on the recapture of fish tagged at the Talkeetna Station fishwheels and
the radio-tracking studies, some Chinook salmon were known to mill in the Susitna River
upstream of Talkeetna, but then migrated downstream to spawn in tributaries to the Lower River
(Jennings 1985). Chinook salmon spawned exclusively in tributary streams to the Susitna River
(ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett 1985, Thompson 1986).
Vincent-Lang et al. (1984) investigated spawning habitat characteristics used by Chinook salmon
as part of the development of instream flow modeling habitat suitability curves. Measurements
at 265 Chinook salmon redd locations indicated use of depths up to 2.7 feet, velocities up to 4.3
feet per second, and substrates primarily of rubble and cobble (Figure 5.1-8 and Figure 5.1-9;
Vincent-Lang et al. 1984).
5.2. Sockeye Salmon
5.2.1. Abundance/Escapement
Susitna River sockeye salmon are the third most important contributor to the Upper Cook Inlet
(UCI) Management Area behind sockeye salmon from the Kenai and Kasilof rivers (Fair et al.
2009). Sockeye salmon generated an average of nearly $16 million per year from 1999 to 2009
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(Barclay et al. 2010). During 2005 to 2008, the Susitna and Yentna Rivers contributed an
average of 2.2 percent (range 0.7 percent to 4.3 percent) to the UCI commercial harvest based
upon genetic identification of harvested fish (Barclay et al. 2010). Sockeye salmon have
accounted for the second largest salmon escapement to the Susitna River following behind chum
salmon.
There are no estimates of sockeye salmon escapement to the entire Susitna River drainage.
Instead, ADF&G has generated counts for counts to portions of the drainage using weirs at three
lakes, and mark-recapture methods for inriver abundance in the Yentna River and in the Susitna
River above Sunshine (RM 80). Escapement data from 1981 to 2008 were available for the
Yentna River and were useful for understanding past trends in sockeye salmon returns (Figure
5.2-1). The data was based upon expanding sonar counts and apportioning them among the
salmon species determined from fishwheel catch. Yentna River escapements were historically
expanded by 1.95 to estimate escapement to the entire Susitna River, but this is no longer done
(Yanusz et al. 2011). Beginning in 2001, the Yentna River had an escapement target of 90,000
to 160,000 sockeye salmon. Fair et al. (2010) cautioned there is substantial uncertainty
regarding escapement estimates via apportionment of sonar counts and noted the Yentna River
escapement targets were dropped in 2009 and replaced by separate escapement targets for
Chelatna Lake (20,000-50,000) and Judd Lake (25,000 – 55,000) in the Yentna River drainage
and a target was added for Larsen Lake (15,000 – 50,000) in the Talkeetna River drainage.
In 2007 and 2008, ADF&G used mark-recapture methods to estimate inriver abundance and
distribution of sockeye salmon in the Yentna River, and in the mainstem Susitna River above
Sunshine (river mile 80; Yanusz et al. 2011). Point estimates of abundance for the Susitna River
above Sunshine were 88,000 fish in 2007 and 71,000 fish in 2008. No estimate was generated in
2006 (Yanusz et al 2011).
For the Susitna River, Jennings (1985) reported the minimum average sockeye salmon
escapement between 1981 and 1984 was 248,400 fish. Sockeye salmon entered the river in two
runs (Jennings 1985); the first run was the smaller of the two with a run size generally of less
than 15,000 fish (Jennings 1985, Thompson et al. 1986). The second run was substantially larger
with total escapement estimates ranging from approximately 340,000 to 606,000 fish (ADF&G
1981, Barrett et al.1983, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986; Figure 5.2-2).
The 1981 estimates at Susitna Station were based upon apportioning sonar counts among the
salmon species, while escapement estimates at other Susitna stations are from Peterson mark-
recapture estimates.
Sockeye salmon escapement estimates at Talkeetna Station (RM 103), which ranged from 3,123
to 13,050 fish, were considered an overestimate, because sockeye salmon were observed milling
in the lower reaches of the Susitna River above the Three Rivers Confluence then moved
downstream to spawn (Jennings 1985). Escapement estimates at Curry Station (RM 120) ranged
from 1,281 to 3,593 fish from 1981 to 1985 with a median escapement of 2,800 fish.
Historically, sockeye salmon spawning in the Middle Susitna River represented around 1 or 2
percent of the total Susitna River escapement.
5.2.2. Distribution
Historically, sockeye salmon were present in the mainstem Susitna River up to Devils Canyon
(Jennings 1985). Fried (1994, as cited in Fair 2009) used sonar and fishwheel counts data to
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estimate that between 41 and 59 percent of the sockeye salmon entering the Susitna River
between 1981 and 1985 spawned in the Yentna River drainage. During the two years (i.e., 1984
and 1985) when Peterson estimates were available from both the Sunshine Station and
Flathorn/Susitna Stations, data indicated that 21 to 30 percent of sockeye salmon spawned
upstream of Sunshine Station (Barrett et al. 1985,Thompson 1986). While there was some
uncertainty regarding the precise proportional distribution of sockeye salmon among the
different Susitna River subwatersheds (Fair 2009), the tributaries associated with the Lower
Susitna River were the major sockeye salmon production areas. In addition to the Yentna River,
other Lower River spawning areas included lakes in the Fish Creek drainage (RM 7.0),
Alexander Lake (Alexander Cree drainage, RM 10.1), Whitsol Lake (Kroto Slough drainage RM
35.2), Trapper and Neil Lakes (Deshka River drainage, RM 40), and Fish Lake (Birch Creek
drainage, RM 89.3). Spawning surveys conducted in the Lower Susitna River indicated that
sockeye salmon did not spawn in the main channel, tributary stream mouths or associated
sloughs (ADF&G 1981, Barrett et al. 1983, Barrett et al. 1985).
Yanusz et al. (2007, 2011a, 2011b) radio-tagged 75 sockeye salmon captured by fishwheels at
Sunshine during 2006, 311 during 2007, and 253 during 2008. Sockeye salmon were also radio-
tagged at the Yentna Station. Tracking of tagged fish confirmed the historic data that indicated
sockeye salmon spawn primarily in Susitna River tributaries (Figure 5.2-3). Within the Susitna
River tributaries, spawning occurred in the main channel, sloughs, or in lake systems (inlets,
outlets, and beaches). It is of interest that during 2007 and 2008, more than half of the fish radio-
tagged at Sunshine were returning to the Larson Lake system in the Talkeetna River drainage
(Yanusz et al. 2011b). Also during 2007 and 2008, approximately 2.6 percent and 1.8 percent,
respectively, of the fish tagged at Sunshine spawned in habitats associated with the mainstem
river (Figure 5.2-4). During 2007, 17 fish tagged at Sunshine were not assigned a spawning
location (Yanusz et al. 2011). These included seven fish last recorded below the Talkeetna River
mouth, one fish that moved downstream below the tagging location, one fish that was recorded
in an off-channel area, four fish (possibly two others) that were captured in the sport fishery, two
fish that moved downstream, and one fish that returned to Cook Inlet. Thus, the terminal
locations depicted in Figure 5.2-3 do not necessarily indicate final spawning locations for tagged
fish.
Historically, sockeye salmon spawning in the lower Middle Susitna River was a relatively small
component to the total Susitna River run, but was important as these fish exhibit a life history
pattern that is not dependent upon lakes for juvenile rearing. While juvenile lake rearing is the
norm for most sockeye salmon populations, “river-type” and “ocean-type” life history patterns
have also been identified, particularly in glacial rivers (Gustafson and Winans 1999). Unlike the
Lower Susitna River, which has had substantial amounts of spawning habitat in tributaries that
have adjacent lake rearing areas, spawning in the Middle Susitna River occurred primarily in
sloughs and side channels with little use of tributaries or the mainstem. Sockeye salmon
spawning was observed within 24 sloughs of the Middle Susitna River from 1981 to 1985
(Jennings 1985, Thompson et al. 1986).
Sockeye salmon primarily spawned in Sloughs 11, 8A, and 21 (Table 5.2-1; Figure 5.2-5). Some
sloughs were used for spawning by sockeye salmon in all years while others were only
intermittently used.
Although sockeye salmon spawning was rarely observed within tributaries of the Middle Susitna
River, Roth and Stratton (1985) reported the capture of sockeye salmon fry in the Indian River
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during July and August 1984. No adult sockeye salmon were observed in tributaries to the
Middle Susitna River during 1981 through 1983. Barrett et al. (1985) observed one sockeye
salmon adult in Indian River and 12 in Portage Creek during 1984, but suspected most were
milling; only one pair of sockeye salmon were spawning. During 1985, Thompson et al. (1986)
observed two adult sockeye salmon in the Indian River, but no spawning activity. Few lake
systems were accessible to sockeye salmon between Talkeetna and Devils Canyon and none
were regularly monitored by ADF&G (Fair 2010).
5.2.3. Age of Return
On average, sockeye salmon predominately returned to the Susitna River at Age 5 (56.6 percent)
and Age 4 (37.0 percent) with a few Age 3 and Age 6 (Figure 5.2-6; ADF&G 1981, ADF&G
1982c, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986).
5.2.4. Periodicity
The first sockeye salmon run entered the Susitna River in late May to early June and spawned in
the Fish Lake Creek system in the Yenta River and the Papa Bear Lake system (Fish Creek
drainage) of the Talkeetna River (Barrett et al. 1985). Some first run sockeye salmon may have
temporarily held in the Middle Susitna River, but did not use it for spawning (Barrett et al.
1985). Spawning in the Papa Bear Lake system occurred in mid-July. During 1984 (Barrett et
al. (1985) observed no carcasses, but 500 to 1,000 sockeye salmon were staging near the creek
mouth and about 1,500 fish were in the early stages of spawning on July 14. By July 26th most
fish were in post spawning condition.
The second run began in late June with the peak occurring in late July and early August for the
Middle Susitna River (Figure 5.2-7). Spawning began in early August and ended in early
October with peak spawning during the last week of August through the third week in September
(Schmidt and Bingham 1983, Thompson et al. 1986).
5.2.5. Holding and Spawning Habitat Utilization
Very little information was available regarding sockeye salmon adult holding areas or habitat
use. No sockeye salmon were radio-tagged during the 1980s studies; however, salmon with Floy
or Peterson disc tags attached at the Talkeetna or Curry fishwheels were often relocated at
downstream spawning locations. These data indicated that some fish would enter and mill in the
Middle Susitna River prior to movement back downstream (ADF&G 1981, ADF&G 1982c,
ADF&G 1984, Barrett et al. 1985). During 1982 set nets were fished for 19.6 hours in lower
Devils Canyon at RM 150.2 and 150.4 between August 10 and September 12 and electrofishing
occurred four times between August 11 and September 23. No sockeye salmon were captured
(ADF&G 1982c).
During 2006 to 2008 Yanusz et al. (Yanusz et al.2007, Yanusz et al.2011a, Yanusz et al. 2011b)
radio-tagged over 1500 sockeye salmon in the Susitna River. However, the objectives of the
studies were primarily to estimate escapement and determine the distribution and location of
spawning. Mainstem macrohabitat types (e.g., main channel, side channel, side slough, tributary,
tributary mouth) were not reported in detail and mesohabitat types (e.g., cascades, rapids, riffles,
runs, or pools) were not reported at all.
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Within the Middle Susitna River sockeye salmon spawned in side channel or side slough habitats
that were associated with upwelling (Jennings et al. 1985). Schmidt and Bingham (1983)
reported that sockeye salmon selected slower, deeper pools with rubble-cobble substrate for
spawning. Measurements at 81 sockeye salmon redd locations indicated use of depths up to 3.0
feet, velocities up to 1.0 feet per second, and substrates primarily of large gravel and rubble
(Figure 5.2-8 and Figure 5.2-9; Vincent-Lang et al. 1984).
5.3. Chum Salmon
5.3.1. Abundance/Escapement
Chum salmon have been the most abundant anadromous salmon returning to the Susitna River
Basin with the exception of even-year pink salmon runs. Chum salmon have been an important
component to the commercial salmon fishery with an average of 478,000 caught in the UCI
Management Area during 1966 to 2006 (Merizon et al. 2010). Chum salmon also have
contributed to the sport fishery with an average of 2,893 captured during 1998 to 2007 (Merizon
et al. 2010). In 2009, Merizon et al (2010) began a four-year study to describe spawning
distribution of chum salmon throughout the drainage. This study was expanded in 2010 to add
escapement estimates, results of which are pending (Cleary al. in prep). ADF&G conducts aerial
surveys for chum salmon on only one stream in all of Upper Cook Inlet, and there are no
escapement goals for chum salmon in the Susitna River drainage (Fair et al. 2010).
Based upon sonar counts to the Yentna River plus the Peterson estimates to the Sunshine Station,
minimum chum salmon returns to the Susitna River averaged 440,751 fish (range 276,577 to
791,466) from 1981 through 19852 (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al.
1985, Thompson et al. (1986). These counts were considered minimums because sonar counts at
the Yentna River station underestimated the total returns (Jennings 1985). The average returns
to the Talkeetna Station during a similar time period was 54,640 chum salmon, but this was
probably an overestimate since chum salmon have been documented entering the Middle Susitna
River and then migrating back downstream to spawn in Lower River habitats (Figure 5.3-1).
The Talkeetna Station was not operated during 1985. Average returns to Curry Station were
21,993 fish (range 13,068 to 29,413) from 1981 to 1985. The returns to Curry Station were
likely reasonable estimates of the returns to the Middle Susitna River because all of the known
primary spawning areas are upstream of Curry Station.
5.3.2. Distribution
Historically, chum salmon were present in the Susitna River basin from the mouth to Devils
Canyon (RM 151) and in most accessible tributaries (Jennings et al. 1985). Low capture rates
early in the chum salmon run resulted in extremely wide error bands for the chum salmon
estimate at Flathorn Station; the east bank fish wheel was relocated on July 29 to improve chum
salmon capture efficiency (Thompson et al. 1986). Chum salmon counted at the Yentna Station
represented 3 to 7 percent (average 5 percent) of the combined escapement estimated at the
2 No estimate was available for the Yentna River during 1985 and the estimate at the downstream Flathorn Station was 56,800
fish lower than the Sunshine estimate. Consequently, the minimum chum run size for 1985 was estimated using the Sunshine
estimate plus the four-year average at the Yentna Station from 1981 to 1984.
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Yentna and Sunshine Stations (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al.
1985). Merizon et al. (2010) radio-tagged 239 chum salmon at Flathorn during 2009 and
assigned a spawning location to 210 of the tagged fish. Chum salmon were strongly oriented
toward the east or west banks. Consequently, fish captured and tagged on the west side of the
river primarily entered the Yentna River, while those captured on the east side tended to migrate
up the Susitna River. Ten (4.8 percent) of the 210 chum salmon tagged at Flathorn and assigned
a spawning location were assigned as spawning in the Middle Susitna River and none entered
tributaries (Figure 5.3-2; Merizon et al. 2010). For the Lower Susitna River, 99 (47.1 percent of
those assigned a spawning location) chum salmon spawned in the Yentna River drainage, 33
(15.7 percent) spawned in the Lower Susitna River mainstem, and 107 (50.9 percent) spawned in
tributaries to the Lower River other than the Yentna River drainage (primarily the Talkeetna,
Deshka, and Chulitna drainages).
Spawning surveys were conducted each year from 1981 to 1985, but the level of intensity varied
from year to year. In 1982, spawning surveys conducted at 811 sites in the Lower Susitna River
did not identify any chum salmon spawning locations in the main channel (Barrett et al. 1983).
However, Barrett et al. (1984) and Thompson et al. (1986) conducted intensive surveys during
1984 and 1985 and identified chum salmon tributary and slough spawning locations in the Lower
and Middle River (Figure 5.3-3). During 1984 Barrett et al. (1985) documented spawning in
twelve non-slough and five slough habitats in the mainstem of the Lower River. Indian River
and Portage Creek account for the majority tributary spawning in the Middle Susitna River while
Sloughs 11, 8A, and 21 account for the majority of slough spawning. During 1984 Barrett et al.
(1985) identified 36 non-slough spawning areas in the mainstem of the Middle Susitna River.
Peak counts in these areas ranged from 1 to 131 (HRM 136.1) chum salmon. During 1985, with
relatively poor viewing conditions, Thompson et al. (1986) identified three mainstem spawning
areas with 13 to 17 peak chum salmon counts.
While there is some uncertainty regarding the precise proportional distribution of chum salmon
among the different Susitna River spawning areas due to annual variations, the tributaries
associated with the Lower Susitna River are the major chum salmon production areas with lower
amounts of production from mainstem channels and sloughs. The Middle Susitna River
mainstem channels, sloughs, and tributaries also account for a small, but significant portion of
the total river chum salmon production.
5.3.3. Age of Return
Chum salmon have predominately returned to the Susitna River at Age 4 (80.0 percent) and Age
5 (12.8 percent) with a few Age 3 and Age 6 fish returning (Figure 5.3-4; ADF&G 1981,
ADF&G 1982c, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986). The age structure
during 1983 was anomalous with predominance of Age 5 rather than Age 4 fish.
5.3.4. Periodicity
Adult periodicity information was available from fishwheels and Bendix sonar stationed at a
number of locations in the mainstem Susitna River and in the Yentna River (Table 3.1-3).
Historically, adult chum salmon began their upstream migration in late May to early July
(Jennings 1985, ADF&G 1984; Figure 5.3-5). Although a few chum salmon passed Sunshine
Station (RM 80) as late as the last week of September, nearly all chum salmon (95 percent)
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passed the station by the first week of August (ADF&G 1981, Jennings 1985). Run timing
(decreased fishwheel catch rates) may have been affected by high flow levels; however, this
pattern was not consistent across all years (Jennings 1985). Chum salmon spawning generally
began in mid-July and was finished by the end of August (Barrett 1985, Jennings 1985). Peak
spawning in streams was during the last week of August while spawning in mainstem sloughs
typically peaked during the first two weeks of September (Jennings 1985). However, during
1985 a secondary peak of chum salmon spawning occurred the last week of September at Slough
8B and to a lesser extent other sloughs (Thompson et al. 1986).
5.3.5. Holding and Spawning Habitat Utilization
Very little information was available regarding chum salmon adult holding areas or habitat use.
During 1981 and 1982, radio tags were used to track 11 and 18 chum salmon, respectively
(ADF&G 1981, ADF&G 1982c). The objectives of the studies were to determine migration
timing, milling behavior, and the distribution and location of spawning. In addition to the radio-
tracking studies chum salmon were also tagged with Floy or Peterson disc tags attached at the
Flathorn/Susitna, Sunshine, Talkeetna, or Curry fishwheels.
During 1981, three chum salmon displayed holding behavior near the mouth of Fourth of July
Creek (3 days and 11 days, 2 fish) or Lane Creek (6 days, 1 fish). During 1982, 6 of 10 chum
salmon radio-tagged at Talkeetna Station eventually moved downstream and entered the
Talkeetna River. Two of these fish moved as far upstream as Curry Station before returning
downstream. Two fish tagged in lower Devils Canyon were observed to enter Portage Creek, but
one later moved to Indian River for spawning while the other moved downstream and was last
observed in the mainstem Susitna River below RM 97. The radio tagging studies in 1981 and
1982 suggested that some chum salmon make substantial upstream and downstream movements
prior to spawning and that holding behavior may occur near the mouths or within tributary
streams. A radio-tracking study in 2009 with 239 chum salmon tagged at Flathorn generally
supported the behavior patterns observed during the 1980s. Merizon et al. (2010) reported that
milling behavior was observed for 23.4 percent of the fish and 3.5 percent entered more than one
tributary prior to spawning.
Recoveries of chum salmon tagged with Peterson disc or Floy tags also supported the notion that
chum salmon mill or temporarily hold in the Middle Susitna River prior to moving downstream
to spawn (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al. 1985). During 1982 set
nets were fished for 19.6 hours in lower Devils Canyon at RM 150.2 and 150.4 between August
10 and September 12 and electrofishing occurred four times between August 11 and September
23. The effort resulted in the capture of 25 chum salmon, indicating that lower Devils Canyon is
used as a holding area by chum salmon (ADF&G 1982c).
Within the Middle Susitna River chum salmon spawned primarily in tributary streams; however,
a substantial number of chum salmon also spawned in side channel or side slough habitat that
was associated with upwelling (Jennings et al. 1985). Measurements at 333 chum salmon redd
locations indicated use of depths up to 2.8 feet, velocities up to 4.5 feet per second, and
substrates primarily of large gravel and rubble (Figure 5.3-6 and Figure 5.3-7; Vincent-Lang et
al. 1984).
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5.4. Coho Salmon
5.4.1. Abundance/Escapement
Historically, coho salmon have been the least abundant anadromous salmon returning to the
Susitna River Basin. Coho salmon have been an important component to the commercial salmon
fishery with an average of 313,000 caught in the UCI Management Area during 1966 to 2006
(Merizon et al. 2010). Next to Chinook salmon, coho salmon have been the second highest
contributor to the sport fishery with an average of 40,767 captured during 1998 to 2007 (Merizon
et al. 2010).
In 2002, Willette et al (2003) used radio tags applied in Upper Cook Inlet to generate an
escapement estimate of 663,000 coho salmon for the Susitna River (95% CI of 435,000 –
892,000 fish) and to describe coho salmon distribution throughout the drainage. The estimate
was split out separately for the Yentna River and the rest of the Susitna River drainage. In 2009,
Merizon et al (2010) began a four-year study to describe spawning distribution of coho and
salmon throughout the drainage. This study was expanded in 2010 to add escapement estimates,
results of which are pending (Cleary al. in prep). Coho salmon are also recorded incidentally at
the Yentna River sonar site, which is operated primarily for sockeye salmon and not considered
to provide complete estimates of other species (Westerman and Willette 2011). There are no
escapement goals for coho salmon in the Susitna River drainage (Fair et al. 2010).
Based upon sonar counts to the Yentna River plus the Peterson estimates to the Sunshine Station,
minimum coho salmon returns to the Susitna River have averaged 61,986 fish (range 24,038 to
112,874) from 1981 through 1985 (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al.
1985, Thompson et al. (1986). These were considered minimums, because sonar counts at the
Yentna River station underestimated the total returns to the Yentna River (Jennings 1985). The
average returns to the Talkeetna Station from 1981 to 1984 was 5,666 coho salmon (Figure 5.4-
1), but this was probably an overestimate, because radio-tracking studies and traditional tag
recaptures have indicated that coho salmon enter the Middle Susitna River and then migrate back
downstream to spawn. The Talkeetna Station was not operated during 1985. Average returns to
Curry Station were 1,613 fish (range 761 to 2,438) from 1981 to 1985. The returns to Curry
Station were likely underestimates of the returns to the Middle River based on milling behavior
described previously and the fact that one of the known primary spawning areas, Whiskers
Creek, is downstream of Curry Station.
5.4.2. Distribution
Coho salmon have been documented in the Susitna River basin from the mouth to Devils Canyon
(RM 151) and most accessible tributaries (Jennings et al. 1985). Historically, coho salmon
counted at the Yentna Station represented 16 to 46 percent (average 35 percent) of the combined
Yentna and Sunshine Stations counts (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et
al. 1985). Merizon et al. (2010) radio-tagged 300 coho salmon at Flathorn during 2009 and
assigned a spawning location to 275 of the tagged fish. Coho salmon were strongly oriented
toward the east or west banks. Consequently, fish captured and tagged on the west side of the
river primarily entered the Yentna River, while those captured on the east side tended to migrate
up the Susitna River. Four (1.5 percent) of the 275 coho salmon tagged at Flathorn and assigned
a spawning location spawned in the Middle Susitna River, and none entered tributaries (Figure
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5.4-2; Merizon et al. 2010). For the Lower River, 130 (47.3 percent of those assigned a
spawning location) coho salmon spawned in the Yentna River drainage, 39 (14.2 percent)
spawned in the Lower River mainstem, and 102 (37.1 percent) spawned in tributaries to the
Lower Susitna River other than the Yentna River drainage (primarily the Talkeetna, Deshka, and
Chulitna drainages).
Spawning surveys were conducted each year from 1981 to 1985, but the level of intensity varied
from year to year. During 1982, spawning surveys conducted at 811 sites in the Lower Susitna
River did not identify any coho salmon spawning in the main channel (Barrett et al. 1983).
Barrett et al. (1985) and Thompson et al. (1986) documented coho salmon spawning in
tributaries of the Middle Susitna River (Figure 5.4-3). However, in 1984, Barrett et al. (1985)
identified two non-slough and one slough spawning areas in the mainstem of the Lower Susitna
River. They also identified 11 tributary mouths that were used as holding habitat, but not for
spawning. Whiskers Creek, Indian River and Chase Creek (RM 106.9) account for the majority
of the tributary spawning in the Middle Susitna River. Thompson et al. (1986) observed coho
salmon milling in five sloughs of the Middle Susitna River during 1985 and Barrett et al. (1985)
observed milling three sloughs during 1984, but no spawning activity was observed in sloughs
during either year. During 1984 Barrett et al. (1985) identified one non-slough spawning area
with two coho salmon in the mainstem of the Middle Susitna River.
While there is some uncertainty regarding the precise proportional distribution of coho salmon
among different Susitna River spawning areas, tributaries associated with the Lower River were
the major coho salmon production areas, and mainstem channels and sloughs were occasionally
used. The Middle Susitna River tributaries support spawning coho salmon but account for a
small portion of the total river production. Middle River mainstem habitats have been used for
holding and, albeit rarely, spawning by coho salmon (Jennings 1985).
5.4.3. Age of Return
On average, coho salmon have predominately returned to the Susitna River at Age 4 (58.0
percent) and Age 3 (40.4 percent) with a few Age 5 (Figure 5.4-4; ADF&G 1981, ADF&G
1982c, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986).
5.4.4. Periodicity
Adult periodicity information was available from fishwheels and Bendix sonar stationed at a
number of locations in the mainstem Susitna River and in the Yentna River (Table 3.1-3). Adult
coho salmon began their upstream migration in early to mid-July (Jennings 1985, ADF&G 1984;
Figure 5.4-5). Although a few coho salmon passed Sunshine Station (RM 80) as late as the last
week of September, most (95 percent) passed the station by the end of August (ADF&G 1981,
Jennings 1985). Run timing (decreased fishwheel catch rates) may have been affected by high
flow levels; however, this pattern was not consistent across all years (Jennings 1985). Coho
salmon spawning generally began in early August and was finished by the first week of October
(Barrett 1985, Jennings 1985). Peak spawning in streams occurred during the first two weeks of
September (Jennings 1985). However, during 1985 a secondary peak of chum salmon spawning
occurred the last week of September at Slough 8B and to a lesser extent other sloughs
(Thompson et al. 1986).
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5.4.5. Holding and Spawning Habitat Utilization
Very little information was available regarding coho salmon adult holding areas or habitat use.
Radio tags were used to track 20 coho salmon during 1981 and 16 during 1982 (ADF&G 1981,
ADF&G 1982c). The objectives of the studies were primarily to determine migration timing,
milling behavior, and the distribution and location of spawning. In addition to the radio-tracking
studies, some coho salmon were collected at the Flathorn/Susitna, Sunshine, Talkeetna, and
Curry fishwheels and tagged with Floy or Peterson disc tags.
During 1981, five chum salmon displayed holding behavior near the mouths of Gash Creek,
Fourth of July Creek, and Little Portage Creek for periods ranging from several days to several
weeks. During 1982 six of ten chum salmon radio-tagged at Talkeetna Station eventually moved
downstream and entered Whiskers Creek, Birch Creek, or the Talkeetna River. The radio
tagging studies in 1981 and 1982 indicated that some coho salmon made substantial upstream
and downstream movements prior to spawning and that holding behavior may occur near the
mouths of tributary streams prior to entering the stream for spawning. A radio-tracking study in
2009 with 300 coho salmon tagged at Flathorn generally supported the behavior patterns
observed during the 1980s. Merizon et al. (2010) reported that milling behavior was less
frequently observed for coho salmon (15.5 percent of fish assigned with spawning location)
compared to chum salmon (23.4 percent) and substantially more coho salmon (50.2 percent)
compared to chum salmon (38.1 percent) made consistent upstream movements throughout the
tracking period.
Recoveries of coho salmon tagged with Peterson disc or Floy tags supported the hypothesis that
many chum salmon mill in the downstream reaches of the Middle Susitna River prior to
spawning elsewhere (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al. 1985). During
1982 set nets were fished for 19.6 hours in lower Devils Canyon at RM 150.2 and 150.4 between
August 10 and September 12 and electrofishing occur four times between August 11 and
September 23. These efforts resulted in the capture of three coho salmon indicating some coho
salmon have used lower Devils Canyon for milling and/or holding (ADF&G 1982c). This is not
surprising given the use of Portage Creek, located a few miles downstream, as an important coho
salmon spawning tributary in the Middle Susitna River.
Coho salmon primarily spawn in tributary streams, with relatively little use of main channel, side
channels, or sloughs. Unlike Chinook salmon, chum salmon, and sockeye salmon, micro-habitat
measurements were not made at coho salmon redds during the 1980s. Consequently, there is no
drainage-specific depths and velocity data for coho salmon spawning habitat.
5.5. Pink Salmon
5.5.1. Abundance/Escapement
Pink salmon have a strict two-year life history. Consequently, even and odd year populations are
genetically distinct stocks. During even years pink salmon are often the most abundant
anadromous salmon returning to the Susitna River Basin. Pink salmon account for a substantial
portion of the commercial salmon fishery with an average of 88,000 fish caught during odd years
and 34,000 fish caught during even years in the UCI Management Area during 1997 to 2009
(Shields and Dupuis 2012). However, pink salmon represent a small proportion of the total ex-
vessel value of salmon in the UCI Management Area (<0.1 percent).
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Based upon sonar counts to the Yentna River plus the Peterson estimates to the Sunshine Station,
minimum pink salmon returns to the Susitna River averaged 546,888 fish (range 85,554 to
1,386,321) from 1981 through 1985 (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et
al. 1985, Thompson et al. (1986). These were considered minimums, because sonar counts at the
Yentna River station underestimated the total returns to the Yentna River (Jennings 1985). The
average returns to the Talkeetna Station from 1981 to 1984 was 65,684 pink salmon (Figure 5.5-
1), but this was probably an overestimate because traditional tag recaptures have indicated pink
salmon have entered the Middle Susitna River and then migrated back downstream to spawn.
The Talkeetna Station was not operated during 1985. Average returns to Curry Station were
22,437 fish (range 1,041 to 58,835) from 1981 to 1985.
ADF&G has operated a counting weir at TRM 7.0 on the Deshka River (RM 40.6) since 1995.
The weir was built and operated for counting Chinook salmon. In recent years, the counting
operation ceased prior to the completion of the pink salmon run. Consequently, recent pink
salmon escapement counts to the Deshka River were underestimates. Nevertheless, the available
information suggests the Deshka River has been also an important spawning tributary in the
lower river for pink salmon with escapement estimates of up to 1.2 million fish.
In 2012, ADF&G began a mark-recapture study to identify major spawning locations of pink
salmon throughout the Susitna River drainage (Cleary al. in prep). Pink salmon are also
recorded incidentally at the Yentna River sonar site, which is operated primarily for sockeye
salmon and not considered to provide complete estimates of other species (Westerman and
Willette 2011). There are no pink salmon escapement goals in the Susitna River drainage (Fair et
al. 2010).
5.5.2. Distribution
Pink salmon have been documented in the Susitna River basin from the mouth to Devils Canyon
(RM 151) and in most accessible tributaries (ADF&G 1982c, Jennings et al. 1985). Spawning
primarily occurs in tributaries to the Susitna River. Counts at the Yentna Station have indicated
that this tributary has been an important producer of pink salmon. These counts have represented
27 to 60 percent (average 45 percent) of the combined escapement estimated at the Yentna and
Sunshine Stations (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al. 1985). Counts
of pink salmon at the Deshka River weir indicated that this tributary was also an important pink
salmon production area in the Lower Susitna River (Figure 5.5-2).
Spawning surveys were conducted each year from 1981 to 1985, but the level of intensity varied
from year to year. Spawning surveys conducted at 811 sites in the Lower Susitna River during
1982 did not identify any pink salmon spawning locations in the main channel (Barrett et al.
1983). Barrett et al. (1985) and Thompson et al. (1986) conducted intensive surveys in 1984 and
1985 and found pink salmon spawning in tributaries of the Lower and Middle Susitna River.
The reports concluded that pink salmon did not spawn in main channel habitat.
In the Lower Susitna River most pink salmon spawned in Birch Creek, Willow Creek, and
Sunshine Creek. During 1984, Barrett et al. (1985) identified both Birch Creek (5 percent of
peak survey counts) and Birch Creek Slough (59 percent of peak survey counts) as important
spawning locations in the Lower River. Birch Creek Slough was the only slough habitat in the
Lower River with significant pink salmon spawning during 1984. In contrast, during 1985,
Thompson et al. (1986) identified Birch Creek as a spawning area that accounted for 55 percent
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of the peak survey counts in the Lower Susitna River. Most of the pink salmon counted in Birch
Creek Slough were live, up to 9,917 fish, while 222 or fewer pink salmon were dead. Thus, it is
possible that Birch Creek Slough provided holding habitat for fish spawning in Birch Creek, with
little to no spawning in the slough.
Indian River (RM 138.6), Portage Creek (RM 148.9), 4th of July Creek (RM 131.1), and Lane
Creek (RM 113.6) accounted for the majority of the pink salmon tributary spawning in the
Middle Susitna River (Figure 5.5-3). Pink salmon holding or spawning occurred in a number of
sloughs within the Middle Susitna River. Habitat use was not consistent from year to year.
Barrett et al. (1984) identified 17 sloughs that pink salmon occupied, but only ten of the sloughs
were used for spawning. Barrett et al. (1985) identified Sloughs 8A, 11, and 20 as the most
important for pink salmon spawning. In contrast, during 1985 Thompson et al. (1986) observed
pink salmon in seven sloughs and a peak dead fish count of 5 fish in Slough 16. During 1985,
pink salmon were only observed in one (Slough 20) of the three sloughs considered important
during 1984. Use of sloughs for spawning by pink salmon in the Middle Susitna River may in
part depend upon run strength, which is typically larger during even years.
While there is some uncertainty regarding the precise proportional distribution of pink salmon
among the different Susitna River spawning areas, the tributaries associated with the Lower
Susitna River, primarily the Deshka, Talkeetna, and Yentna rivers, have been the major pink
salmon production areas. The Middle Susitna River tributaries have accounted for a small
portion of the total Susitna River pink salmon production.
5.5.3. Periodicity
Adult periodicity information was primarily available from fishwheels and Bendix sonar
stationed at a number of locations in the mainstem Susitna River and in the Yentna River (Table
3.1-3). Adult pink salmon began their upstream migration in late June to early-July (Jennings
1985, ADF&G 1984; Figure 5.5-4). Although a few pink salmon passed Sunshine Station (RM
80) as late as the second week of September, nearly all pink salmon (95 percent) passed the
station by the third week of August (ADF&G 1981, Jennings 1985). Run timing (decreased
fishwheel catch rates) may have been affected by high flow levels; however, this pattern was not
consistent across all years (Jennings 1985). Pink salmon spawning generally began in early
August and was finished by the first week of October (Barrett 1985, Jennings 1985). Peak
spawning in streams was during the first three weeks of August (Jennings 1985). Pink salmon
spawning in sloughs occurred slightly later and more variable than tributary spawning. In 1981
peak spawning sloughs was the last week of August, but was during the first three weeks of
August in 1982, occurred from mid-August to the first week of September in 1984, and the last
week of August in 1985 (Jennings 1985, Barrett et al. 1985, Thompson et al. 1986). No pink
salmon were observed to spawn in sloughs during 1983 (Jennings 1985).
5.5.4. Holding and Spawning Habitat Utilization
There was no information available specific to Susitna River pink salmon adult holding areas or
habitat use from work conducted in the 1980s. No radio-tracking studies were conducted on
pink salmon during the 1980s. Peterson or Floy tags were attached to pink salmon at fishwheel
stations for use in mark-recapture abundance estimation and to estimate migration rates, but were
not helpful in understanding habitat utilization. Unlike Chinook salmon, chum salmon, and
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sockeye salmon, micro-habitat measurements were not made at pink salmon redds during the
1980s. Consequently, there was no drainage-specific information regarding pink salmon
spawning habitat for the Susitna River.
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6. EGG INCUBATION
Egg incubation is an important life stage for salmon and trout because a substantial amount of
the freshwater rearing period, more than six months for chum salmon, can be spent developing
into free swimming fry within redds. During this stage, eggs and alevin are relatively immobile.
Consequently, there is no way to avoid factors such as temperature, water quality, or fines that
can adversely affect survival to emergence.
Because chum salmon and sockeye salmon are the principle salmon species using side channels
and side sloughs for spawning in the Susitna River (Sautner et al. 1984), egg development and
incubation studies were conducted on these two species and focused on chum salmon. Studies
included monitoring of surface and intergravel water temperatures, egg development, spawning
substrate composition, and trapping of emergent fry.
6.1. Egg Survival
Vining et al. (1985) reviewed the rationale and importance of studying redd stranding in the
Susitna River. Declines in mainstem flow levels following spawning can result areas that were
suitable for spawning becoming dewatered or having an increased risk of freezing. Chum
salmon in the Susitna River frequently select areas of groundwater upwelling for spawning.
Vining et al. (1985) noted that selection for upwelling areas is not unique to the river and has
been observed in the Amur River of Russia regions, British Columbia, the Columbia River, and
other areas of Alaska. Upwelling areas can have the dual effect of preventing redd freezing and
providing a stable thermal regime for developing eggs.
Vining et al. (1985) had two objectives:
1) Monitor selected physical and chemical conditions at chum salmon incubation sites in
selected slough, side channel, tributary, and mainstem habitats of the middle Susitna
River; and,
2) Evaluate the influence of selected physical, chemical, and biological variables on the
survival and development of chum salmon embryos placed in artificial redds in slough,
side channel, tributary, and mainstem habitats of the middle Susitna River.
These researchers selected eight primary sites within slough, side channel, tributary, and
mainstem habitats that included a range of conditions for: spawning density, upwelling,
temperature, and substrate. Primary sites were sampled for water quality, substrate composition,
continuous water temperature, embryo survival, and embryo development. The primary sites
included:
Fourth of July Creek (RM 131.1)
Slough 10 (RM 133.8)
Side Channel 10 (RM 133.8)
Slough 11 (RM 135.3)
Upper Side Channel 11 (RM 136.1)
Mainstem (RM 136.1)
Side Channel 21 (RM 141.0
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Slough 21 (RM 141.8)
They also selected eight secondary sites that were only monitored for water quality conditions.
The selected sites were a subset of those used in instream flow spawning analyses conducted by
Vincent-Lang et al. (1984). Standpipes were used collect intergravel water samples and
measurements. Sediment samples were collected using a McNeil Sampler. Water quality
measurements included dissolved oxygen, pH, conductivity, and turbidity. Depths and velocities
were periodically collected at each site.
Chum salmon survival and development was studied by artificially spawning chum salmon and
placing 50 fertilized eggs in Whitlock-Vibert Boxes (WVBs) containing appropriately sized
gravel. To evaluate egg survival, WVBs were subsequently placed into artificial redds dug at
randomly selected locations from a grid pattern. To evaluate egg development EVBs at two sites
were placed in a single artificial redd. Artificial redds at most sites were created shortly after the
fertilization process on August 26, 1983. However, some artificial redds at the Mainstem RM
136.1 were dug on October 1 because water depths were too high for digging prior to that date.
For these sites, eggs were temporarily incubated in streamside incubators prior to burying in
artificial redds.
During the 1984-1985 winter study, chum salmon egg survival in artificial redds ranged from 0.0
percent (Side Channel 21 subsite A) to 43.0 percent (Slough 21; Vining et al. 1985; Figure 6.1-
1). They concluded that freezing was the major factor affecting egg survival in the artificial
redds and that upwelling was the main moderating factor. Upwelling contributed two important
functions: it maintained flow when surface flows declined; and it provided warmer water that
reduced ice cover and deep freezing of substrate. Vining et al. (1985) stated:
“The areas which were observed as being the most susceptible to high embryo
mortality due to surface dewatering and freezing in this study were those most
directly influenced by mainstem stage at the time when fish were actively
spawning (mid August - mid September) and which lacked an upwelling water
source. These areas include the mouths of sloughs and tributaries, major
portions of side channels, and peripheral areas in the mainstem river. In each of
these areas, water levels were significantly higher during the spawning period
when fertilized eggs were deposited. However, as the mainstem stage decreased
with winter flows, these areas progressively became dewatered and were exposed
to freezing ambient temperatures.“
Events at Side Channel 21 were particularly important to their conclusion (Vining et al. 1985).
Egg boxes (40) were initially buried (subsite A) during a period when mainstem flows were high
(27,000 cfs) and the berm at the head of the side channel was breached, which resulted in
relatively high water elevations in the side channel. Two weeks later they returned when
mainstem flows were 11,000 cfs and the berm was no longer breached. All redds in areas
without upwelling were dewatered. At that time, they buried an additional 20 egg boxes in an
area (subsite B) that was still wet. Mainstem flows continued to fall throughout the winter. All
of the eggs that were buried at subsite A died from dewatering and freezing while 16 percent
survival was observed at subsite B. Vining et al. (1985) concluded that effective spawning
habitat that reflected flow and upwelling throughout the incubation period may be different than
the amount of habitat available during spawning.
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Vining et al. (1985) also concluded that sediment composition was also a factor contributing to
egg survival. They observed that slough habitats had the highest level of fines, followed by side
channel, tributary, and mainstem habitats (Figure 6.1-2). However, sediment composition
sampled directly from redds were much lower (Figure 6.1-3). They suggested that egg survival
approaches zero when fines (< 0.08 inches in diameter) in redds exceed 16 percent (Figure 6.2-
4).
6.2. Emergence Timing
Water temperature is the most important determinant of egg development and the timing of
emergence (Quinn 2005). Intragravel water temperature studies began in February 1982, which
led to the development of the following three hypotheses (Trihey 1982).
1) Mid-winter water temperatures in the sloughs are independent of mainstem water
temperatures.
2) River stage appears to be influencing groundwater upwelling in the sloughs.
3) Spawning success at upwelling areas in side channels appears to be limited by
availability of suitable substrate (streambed materials).
In addition to the importance to incubating salmon eggs, groundwater inflows to sloughs were
also considered potentially important to overwintering habitat. During 1982 intragravel
temperature monitoring occurred at thirteen sites between RM 125 and 143 that were identified
from ADF&G 1981 spawning surveys and were thought to have groundwater upwelling.
Measurements of surface and intragravel water temperature at these sites revealed that
intragravel temperatures were higher and more stable than surface water temperatures (e.g.,
Figure 6.2-1).
More intensive winter studies were implemented in March 1983 (Hoffman et al. (1983) and
1984-1985 (Vining et al. 1985; described in the previous section). Hoffman et al. (1983)
reported on surface and intragravel water temperature monitoring at seven sites during the winter
of 1982 to 1983 and also conducted incubation and emergences studies. In addition to water
temperature, Hoffman et al. (1983) also monitored dissolved oxygen, pH, and specific
conductance levels and noted the importance of dissolved oxygen exchange as a factor affecting
egg incubation. Continuous surface and intragravel monitoring sites were established at six
sloughs (Sloughs 21, 19, 16B, 11, 9, and 8A) and the mainstem at LRX 29 and Gold Creek.
Measurements were collected from late August 1982 through early June 1983. Sites were
chosen because they were known chum salmon and/or sockeye salmon spawning locations.
Incubation and emergence studies were conducted at seven sites (sloughs 21, 20, 11, 9 and 8A)
and two side channels (A and B located at RM 136.2 and 137.3, respectively; Hoffman et al.
1983). Standpipes to measure intragravel water temperature and chemistry were located along
each bank of the selected sloughs (10 per bank, 20 total per location). Sampling at these
locations occurred during April 15 to18 and April 29 to May 2. Eggs were sampled once per
month from September 1982 through May 1983 using high pressure water jet to dislodge eggs
into a mesh sack.
The 1982-1983 winter study (Hoffman et al. 1983) and 1984-1985 winter study (Vining et al.
1985) confirmed patterns of surface- and ground-water temperature observed by Trihey (1982).
Intragravel water temperatures in slough habitats tend to be relatively stable (Hoffman et al.
1983). Vining et al. (1985) observed similar patterns for sloughs and side channels with
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upwelling was present. At tributary and mainstem sites Vining et al. (1985 observed that
intragravel temperatures were variable and approach 0°C in October, which indicated intragravel
waters were originating from surface waters. The continuous monitoring stations demonstrated
intragravel water temperatures in areas with upwelling were warmer than surface waters during
the ice covered period. As the spring thaw begins (about mid-April in 1983), intragravel
temperatures then become cooler than surface water temperatures.
Monitoring during three days in mid-April and four days in late-April,1983, at sites with
standpipes placed along slough banks indicated substantial variability in upwelling water
temperatures with no consistent relationship between right bank and left bank standpipes at a site
(e.g., Figure 6.2-2; Hoffman et al. 1983). Average intragravel temperatures were cooler than
surface waters, which was consistent to the patterns observed from continuous monitoring.
Mean intragravel dissolved oxygen measurements ranged from 4.6 mg/L at Slough 8A during
both sampling periods to 8.5 mg/L at Slough 11 during the first sampling period of 1983
(Hoffman et al. 1983). Intragravel dissolved oxygen was substantially lower than surface water
dissolved oxygen that ranged from a mean of 9.1 mg/L at Slough 21 during the first sampling
period to 11.2 mg/L at Slough 8A during the second sampling period. Measurements of pH were
found to be within suitable levels for both intragravel and surface water. Significant differences
and a significant interaction was found for specific conductance between sites and between left
and right banks within the sites. Hoffman et al. (1983) concluded that multiple water sources
were the cause of these differences. Vining et al. (1985) observed similar patterns for dissolved
oxygen and pH. For specific conductance, Vining et al. (1985) observed similar patterns in
sloughs; however, specific conductance was lower in tributary sites, which were not studied by
Hoffman et al. (1983), than slough and mainstem sites.
The sensitivity of the incubating eggs to mechanical shock (e.g., scour), temperature, and
dissolved oxygen changes over the course of egg development (Quinn 2005, Myrick and Cech
2004). Understanding when incubating eggs are more sensitive to perturbations can be important
to assessing potential effects of modified flow or temperature regimes. Sampling chum salmon
and sockeye salmon redds for developing eggs by Hoffman et al. (1983) indicated that chum
salmon eggs deposited during late August and early September of 1982 were eyed by mid-
December, hatched in late February and March and emergence occurred between early April
through May (Figure 6.2-3). The development of sockeye salmon eggs collected from field sites
was not substantially different than chum salmon (Figure 6.2-4).
Egg development was also monitored by Vining et al. (1985). Hatching first occurred in Side
Channel 11 during late to early January, followed by hatching in Slough 11 during January
(Figure 6.2-5). Hatching at the mainstem site did not occur until April. Although interruptions
in temperature monitoring prevented a quantitative comparison of temperature regimes, Vining
et al. (1985) attributed the different development rates to temperature and the effects of
upwelling. Upwelling was relatively strong at Slough 11, present, but relatively weak at Side
Channel 21, and not present at the mainstem site. Vining et al. (1985) concluded that the
presence of upwelling is an important factor contributing to emergence timing and that the
beneficial effects of upwelling are more prominent in sloughs compared to mainstem, side
channel, and tributary habitats because higher surface flows in the latter habitats dilute
upwelling.
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Wangaard and Burger (1983) incubated chum salmon and sockeye salmon eggs fertilized on
three different dates (September 3rd, 9th, and 15th) under four different temperature regimes
(Figure 6.2-6). Two of the regimes simulated natural temperatures measured in mainstem
Susitna River at RM 136 near Gold Creek and at Slough 8A. The third regime tracked the
temperature at Slough 8A, but was 1°C lower. The fourth regime was incubation at a constant
4°C.
Egg development was evaluated based upon accumulated temperature units (ATUs). One ATU
is one day of temperature at 1°C, two ATUs could be two days at 1°C or one day at 2°C.
Consequently, at a constant temperature of 4°C over a five-day period results in 20 ATUs.
ATUs in Wangaard and Burger (1983) were based upon mean daily average temperature. An
example of ATUs based upon fertilization at the time of the first egg collection (September 3rd)
is provided in Figure 6.2-7.
Chum salmon eggs incubated under the mainstem temperature regime required substantially
longer and fewer ATUs to reach the 50 percent hatch and yolk absorption stages compared to the
Slough 8A and constant temperature regimes (Figure 6.2-8; Wangaard and Burger 1983). A
similar pattern was observed for incubating sockeye salmon eggs. Following hatch, alevins
required different amounts of ATUs to complete yolk absorption (Figure 6.2-9). Using data
collected during the study and from the literature, Wangaard and Burger developed predictive
regression equations for 50 percent hatch and complete yolk absorption for chum salmon and
sockeye salmon eggs based upon average incubation temperature (Table 6.2-1).
Bigler and Levesque (1985) monitored surface and intergravel water temperature, egg
development, outmigration, and substrate composition at three Lower River side channels where
relatively high levels of chum salmon spawning was documented. The three sites included the
Trapper Creek side channel (RM 91.6), Sunset Side Channel (RM 86.9), and Circular Side
Channel (RM 75.3). Chum salmon surveys and instream flow modeling were also conducted at
these sites. Egg development was also monitored at the Birch Creek Camp Mainstem (RM 88.6)
site and a fyke net deployed for two days in early May 1984.
Similar to Hoffman et al. (1983), Bigler and Levesque (1985) observed that most of these chum
salmon spawning areas had upwelling and intragravel temperatures were higher than surface
water temperatures. In general, eggs developed thorough the alevin and emergence stage at all
sites. The upper portion of the Sunset Side Channel did not have groundwater upwelling and
eggs laid in this portion of the study site froze. Development of eggs ranged from the caudal bud
free stage to pigmentation stage by late January. Fyke nets to capture emerging fry were
deployed beginning April 15, 1985 and fished periodically. Sockeye salmon fry were captured
on the first day of deployment at the Trapper Side Channel and chum salmon fry were present in
the catch beginning April 30.
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7. JUVENILE SALMON
7.1. Chinook Salmon
7.1.1. Life History Patterns
Susitna River Chinook salmon exhibited very little freshwater life history diversity. Scale
samples from adult Chinook salmon collected at fishwheels indicated that nearly all Chinook
salmon exhibit a stream-type life history pattern and outmigrate to the ocean as yearlings
(ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al. 1985, Thompson et al. 1986).
Plots of the year of life at ocean entry for adults returning in 1983 and 1984 were typical of other
years sampled between 1981 and 1985 (Figure 7.1-1). A small percentage of returning adult
Chinook salmon outmigrated as fry. Roth et al. (1986) explained that the patterns from the
scales represent successful life history patterns. For example, he suggested that a higher
proportion of fry may have left the river than indicated by scale analysis, but they may not have
survived as well as other life stages and thus are not represented in the returning adults.
7.1.2. Periodicity
Historically, Chinook salmon spawning in Susitna River tributary streams peaked during the last
week of July and first week of August (Jennings 1985; Section 5.1.4). Juvenile Chinook salmon
periodicity is depicted in Table 7.1-1. The timing of Chinook salmon fry emergence and
downstream migration in Susitna River tributaries is poorly understood because of the difficulty
of sampling during the spring. High flows following ice-out prevented sampling in most years
prior to mid-May or even early June. In 1981, Delaney et al. (1981) reported that Chinook
salmon fry were collected in Indian River in April as part of winter sampling. In 1982, sampling
did not begin until early June, and Chinook salmon fry were already present (Schmidt et al.
1983). During 1985, sampling in Portage and Indian creeks occurred beginning July 9 and
Chinook salmon fry were being captured at relatively high rates with lengths ranging from 36 to
64 mm (Roth et al. 1986; Figure 7.1-2), indicating that emergence was primarily completed by
that time. Schmidt and Bingham (1983) reported Chinook salmon fry emergence occurs during
April and March while Stratton (1986) reported Chinook salmon fry emerge in April; however,
neither of these authors provides any supporting field sampling data for these conclusions.
As discussed in Section 7.1.1, nearly all Chinook salmon juveniles outmigrated to the ocean as
Age 1+ fish. Understanding the timing of this out-migration both from natal tributaries to the
mainstem Susitna River and again from the Middle Susitna River to Lower Susitna River is
important for assessing the potential effects of the proposed Susitna-Watana Project. During
1983 to 1985, incline plan traps at fixed stations were deployed (Roth et al. 1984, Roth and
Stratton 1985, Roth et al. 1986). The following focuses on the results from 1984 and 1985
because both catch rates and cumulative catch were reported. The general pattern of
outmigration timing in 1983 was consistent with observations during 1984 and 1985.
During 1980s studies, the bulk of Chinook salmon fry outmigrated from Indian and Portage
creeks by mid-August and redistributed into sloughs and side channels of the Middle Susitna
River or migrated to the Lower River (Roth and Stratton 1985, Roth et al. 1986; Figure 7.1-3).
Outmigrant trapping occurred at Talkeetna Station (RM 103) during open water periods from
1982 to 1985 and demonstrated Chinook salmon fry were captured migrating downstream to the
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Lower Susitna River throughout the time traps were operating (Schmidt et al. 1983, Roth et al.
1984, Roth and Stratton 1985, Roth et al. 1986). Peak catch often occurred during periods of
high flows. Outmigrant traps were also fished at Flathorn Station (RHM 22.4) during 1984 and
1985 and demonstrated peak periods of Chinook salmon fry movement during early July;
however, many of these fry may have originated from the Deshka River (Roth and Stratton 1985,
Roth et al. 1986). Based on timing of movements, Roth and Stratton (1986) suggested that some
Chinook salmon fry either overwinter in Lower Susitna River downstream of Flathorn Station or
outmigrate to the ocean as fry. They also suggested that outmigration as fry is a relatively
unsuccessful Chinook salmon life history pattern in the Susitna River because scale pattern
analysis indicates that few adults return.
The capture of a small number of Age 1+ Chinook salmon juveniles in the Indian River during
winter sampling (Stratton 1986) indicated that some Chinook salmon fry remain in natal
tributaries throughout their first year of life. During 1984, sampling in the Indian River failed to
capture any Chinook salmon Age 1+ fish during July, but were successful during May and June,
indicating that Age 1+ Chinook salmon juveniles emigrated from tributary streams shortly after
ice-out (Roth and Stratton 1985). The cumulative frequency of Age 1+ Chinook salmon
juveniles catch at the Talkeetna Station reached 90 percent by early July in 1985 and by late-July
at the Flathorn Station (Roth et al. 1986; Figure 7.1-4). Consequently, outmigrating Chinook
salmon Age 1+ smolts are generally in estuarine or nearshore waters by mid-summer.
7.1.3. Growth
The smallest Chinook salmon fry captured at outmigrant traps were 35 mm during 1984 (Roth
and Stratton 1985) and 32 mm during 1985 (Roth et al. (1986). Growth of Chinook salmon fry
during 1984 and 1985 was similar (Figure 7.1-5). Average size of fry captured at the Flathorn
Station were about 5 to 15 mm larger than fry captured at the Indian River and Talkeetna Station
during the same time period. From early June to Late September, average fry length was larger
at any given site. Differences in Chinook salmon Age 1+ size between Talkeetna and Flathorn
stations appeared less dramatic than for fry during 1984 (Figure 7.1-6; no data available for
1985). Age 1+ Chinook salmon juveniles tended to be around 85 to 95 mm in length during the
peak movement past Talkeetna and Flathorn in late June and early July 1984. Roth et al. (1986)
indicated Age 1+ juveniles averaged 87 mm in length at Flathorn Station and 81 mm in length at
Talkeetna Station during the open water season of 1985. Roth et al. (1986) explained that a
number of factors likely contributed to spatial and temporal differences in mean length for fry
including emergence timing, habitat quality, and water temperatures.
7.1.4. Habitat Utilization
7.1.4.1. Open Water Season
Analyses for habitat utilization were more robust for Age 0 fish because few Age 1+ fish were
captured during the 1982 and 1983 field seasons. A 1982 analysis of Chinook salmon juvenile
catch rates by Schmidt and Bingham (1983, Appendix F) indicated that Chinook salmon
juveniles were more commonly found in tributary zones (Zones 1 and 2, Table 3.1-5) and
backwaters downstream of a tributary mouth (Zone 7). When examined using aggregated
hydraulic or water zones (Table 3.1-6), Chinook salmon juveniles were more abundant in the
tributary water zone (W-I) over mainstem water (W-II) and mixed water (W-III) zones and a
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substantial avoidance for the mainstem mixing zone (H-III) compared to the not mainstem
backwater (H-I) and mainstem backwater (H-II) zones. Little difference in abundance was
demonstrated for fast (V-II) versus slow (V-I) velocity zones.
Schmidt and Bingham (1983, Appendix G) also compared the frequency that juvenile Chinook
salmon were present in five major habitat types using Chi-square analyses. The five major
habitat types were: tributary mouths, upland sloughs, side sloughs with large tributaries, side
sloughs without large tributaries, and side channels with large tributaries. The analysis found no
significant difference in the presence/absence of Chinook salmon juveniles in these five habitat
types. However, a significant difference was found when all salmon juveniles were combined,
with a relatively high frequency of salmon juveniles being present in side sloughs with large
tributaries and a relatively low frequency of observations in tributary mouths. Schmidt and
Bingham (1983) concluded that the habitat types had distinctive salmon juvenile communities.
The 1984 field work (Dugan et al. 1984) tended to contradict the findings from 1983 (Figure 7.1-
7 and Figure 7.1-8). Chinook salmon juveniles had relative high density distribution (61 percent)
in tributaries, followed by side channels (23 percent), side sloughs (9.3 percent), and upland
sloughs (6.7 percent). ANOVA tests suggested that macrohabitat type, sampling period, mean
velocity, and turbidity were significant factors affecting juvenile Chinook salmon CPUE. They
concluded that Chinook salmon juveniles utilized turbid water as cover. They also concluded
that tributaries had a high CPUE because they were the source of Chinook salmon juveniles prior
to dispersing into side channels and sloughs. Outmigration of Age 0+ Chinook salmon juveniles
from the tributaries peaked during early July with a lower peak in mid-August. They suggested
that as temperature drops in September, Chinook salmon juveniles departed side channels and
tributaries to seek side sloughs with upwelling that provided over-wintering habitat.
7.1.4.2. Overwintering
Little information was available regarding over winter habitat use by Susitna River Chinook
salmon. Surveys during the winter of 1980 to 1981 (Delaney et al. 1981) and during 1985 to
1986 (Stratton 1986) provided information on the winter distribution and habitat characteristics.
Delaney et al. (1981) conducted surveys at 87 sites between Alexander Creek (RM 10.1) to
Portage Creek (RM 148.8) using minnow traps as a collection method. Approximately one third
(29) of the sites were standard habitat locations used for open water sampling. The majority of
the sites (53, 61 percent) were in sloughs or tributaries associated with the Middle Susitna River.
Sampling effort was variable with events occurring once per month during one to seven months
between November and May. Chinook salmon juveniles were captured at 59 percent of the sites.
Most (77.4 percent) of the catch occurred from sites in the Middle Susitna River. Whiskers
Creek accounted for over a quarter (27 percent) of the catch. Chinook salmon were consistently
captured throughout the winter in three sloughs in the Middle Susitna River (Slough 8A, Slough
10, and Slough 20) and two sites in the Lower Susitna River (Sunshine Creek and Rustic
Wilderness). Delaney et al. (1981) noted that juvenile Chinook salmon were frequently observed
at tributary mouths during the summer (80 to 100 percent incidence) but less commonly during
the winter (25 percent incidence). They observed that many sloughs were ice-free during winter
and provided what appeared to be rearing habitat throughout the year even though they were not
used by Chinook salmon for spawning. Sites surveyed in both the mainstem and sloughs were
used by coho and Chinook salmon for overwintering habitat (Delaney et al. 1981).
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Stratton (1986) studied overwinter habitat use by Chinook salmon and coho salmon at four
locations (Indian River, Slough 9A, Slough 10, and Slough 22) from October 1985 to April
1986. Fish were captured using minnow traps, cold branded with a mark unique to the time
period and location of sampling and released at the capture site. During the study 33.5 percent of
9,744 marked Chinook salmon were recaptured. Nearly all recaptured Chinook salmon were
located in the same site as where they were marked. Only two were recaptured elsewhere than
the marking site. Based upon declines in the catch of Chinook salmon in the Indian River and
increases in two sloughs downstream, Stratton (1986) concluded that many juvenile Chinook
salmon emigrated from the Indian River during the late-October to mid-January period. He
speculated that the amount of ice cover in the Indian River may have been a factor. Relative to
coho salmon, Chinook salmon juveniles preferred shallower and slightly higher velocity habitat
with cover consisting of rocks and boulders.
Bigler and Lefesque (1985) captured Chinook salmon juveniles using fyke nets at Trapper Side
Channel (RM 92.7; April 15 through May 28), Sunset Side Channel (RM 86.9; May 25 through
May 27), Circular Side Channel (RM 75.3; April 30 through May 24) and Birch Creek Side
Channel (RM 88.6; April 30 through May 2). These data indicated that Chinook salmon may
also have used side channels during the ice-in period.
7.2. Sockeye Salmon
7.2.1. Life History Patterns
There appears to be a moderate amount of freshwater life history diversity for sockeye salmon.
Scale samples from adult sockeye salmon collected at fishwheels indicated that most sockeye
salmon had a stream-type life history pattern and outmigrated to the ocean after overwintering
during their second year of life (ADF&G 1981, ADF&G 1982c, ADF&G 1984, Barrett et al.
1985, Thompson et al. 1986). Plots of the year of life at ocean entry for adults returning in 1983
and 1984 were typical of other years sampled between 1981 and 1985 (Figure 7.2-1). Around
ten percent of returning adult sockeye salmon outmigrated as fry or during their third year. Roth
et al. (1986) explained that the patterns from the scales represented only successful life history
patterns. A higher proportion of fry may have exited the system than indicated by the scale
analysis, but they may not have survived as well as other life stages and thus were not
represented in the samples of returning adults.
While there was relatively low life history diversity related to freshwater rearing, sockeye
salmon life history diversity in the Susitna River was increased by the presence of juveniles that
did not rear in a lake environment, which is an uncommon life history pattern for sockeye
salmon in southern latitudes (Foerster 1968, Burgner 1991), but relatively common in northern
latitude rivers with a predominance of glacial influence (Wood 1995, Gustafson and Winans
1999). Yanusz et al. (2011) observed that many (52 percent in 2008) sockeye salmon within the
Yentna River did not enter a major lake, and substantial spawning occurred in sloughs associated
with the main channel. Sockeye salmon in the Middle Susitna River spawned primarily in
sloughs with upwelling, and occasionally in side channels (Section 5.2.2). The location of
freshwater rearing for juveniles hatched out in sloughs has not been determined.
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7.2.2. Periodicity
A second-run of slough-spawning sockeye salmon peaked during the first three weeks of August
(Jennings 1985; Section 5.2.4). Sockeye salmon fry periodicity is depicted in Table 7.2-1. The
timing of sockeye salmon fry emergence in the Middle Susitna River was fairly well understood
based upon the work by Hoffman et al. (1983) and Wangaard and Burger (1983). Most sockeye
salmon fry emergence occurred in March and is mostly complete by the end of April (Schmidt et
al. 1983, Hoffman et al. 1983). However, based upon the smallest fry sizes reported from
outmigrant traps, some sockeye salmon fry did not emerge until mid- to late-June. Delaney et al.
(1981) sampled Slough 11 and Indian River during March and observed 2,000 pre-emergent pink
salmon, chum salmon, and sockeye salmon alevins. Emerging fry were first captured on March
23, but it was not reported how many were sockeye salmon fry. Most sockeye salmon fry
appeared to emerge at around 32 mm in size (Roth and Stratton 1985). The minimum fry size
collected at the Talkeetna Station outmigration trap during June 16-30 1985 sampling period was
27 mm (Roth et al. 1986).
As discussed in Section 6.1.1, over 90 percent of sockeye salmon juveniles that successfully
returned as adults outmigrated to the ocean as Age 1+ fish. During 1983 to 1985, incline plan
traps at fixed stations were deployed to collect data on migration timing (Roth et al. 1984, Roth
and Stratton 1985, Roth et al. 1986). The following discussion focuses on the results form 1984
and 1985 because both catch rates and cumulative catch were reported. The general pattern of
outmigration timing in 1983 was consistent with observations during 1984 and 1985.
Outmigrant trapping began May 14 during 1984 and May 27 during 1985. Outmigration timing
was influenced by flow and turbidity conditions (Hale 1985). During 1984, some sockeye
salmon fry were captured immediately after trap deployment, but peak capture rates did not
occur at Talkeetna Station until mid-June when peak flows occurred (Figure 7.2-2; Roth and
Stratton 1985). In contrast, peak fry capture rates occurred immediately at the time of trap
deployment during late-May 1985 and was concurrent with the highest flow of the season
(Figure 7.2-3; Roth et al. 1986). Roth and Stratton (1985) concluded that most sockeye salmon
fry from the Middle Susitna River emigrated to the Lower Susitna River by mid-September for
overwintering, because overwintering habitat in the middle river was limited. Nevertheless,
some sockeye salmon fry overwintered in the Middle Susitna River, as evidenced by the capture
of Age 1+ juveniles at the Talkeetna Station outmigrant trap (Figure 7.2-4).
The period of outmigration by Age 1+ sockeye salmon was substantially narrower than fry. The
cumulative frequency of Age 1+ sockeye salmon juveniles catch at the Talkeetna Station reached
90 percent by the third week of June in 1985 and by the end of June at the Flathorn Station (Roth
et al. 1986; Figure 7.2-4). Consequently, outmigrating sockeye salmon Age 1+ smolts were
generally in estuarine or nearshore waters by early summer.
7.2.3. Growth
Most sockeye salmon fry emerged at approximately 32 mm in size (Roth and Stratton 1985).
Growth of sockeye salmon fry during 1984 and 1985 was similar (Figure 7.2-5), and by the end
of September sockeye salmon fry are about 55 to 60 mm in length. Information on the growth of
Age 1+ sockeye salmon juveniles was more limited, because most outmigrate during the late
spring prior to deployment of outmigrant traps. Roth and Stratton (1985) observed that Age 1+
juveniles captured in the spring were an average of 10 mm longer than fry captured at the end of
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the open-water season in the previous year. This indicated that some growth occurred during the
winter and spring period. Roth et al. (1986) suggested that growth potential for fry that
overwintered in the Middle and Lower Susitna River was low compared to fry that rear in lake
systems. During 1985 they observed Age 1+ sockeye salmon juveniles captured at the Talkeetna
Station were 11 mm in length shorter on average than Age 1+ sockeye salmon juveniles captured
at the Flathorn Station (69 mm compared to 80 mm).
7.2.4. Habitat Utilization
7.2.4.1. Open Water Season
Analyses for habitat utilization were more robust for Age 0 fish than for Age 1+ fish due to
greater catch of the younger fish. Schmidt and Bingham (1983) did not report on the relative
abundance of sockeye salmon juveniles by individual habitat zone (Table 3.1-5). Analysis of
sockeye salmon juvenile catch rates within aggregate zones during 1982 by Schmidt and
Bingham (1983, Appendix F) indicated that sockeye salmon were more abundant in turbid
mainstem water in low velocity backwaters. A major exception to this pattern was Slough 6A in
1983, which had relatively high numbers of sockeye salmon juveniles using clear water low
velocity habitat with substantial cover (Dugan et al. 1984). The analysis by Schmidt and
Bingham (1983) indicated sockeye salmon juveniles were more commonly found in aggregated
mainstem backwater zones (Zones 2, 6, 7, and 8; Table 3.1-6) and low-velocity pools. Analysis
of the aggregate hydraulic or water zones, suggested sockeye salmon juveniles demonstrated a
strong preference for the mainstem water zone (W-I) over the mixed water (W-III) zone and a
substantial preference for the mainstem backwater (H-II) and avoidance for the mainstem mixing
zone (H-III) and not mainstem backwater (H-I) zones. Sockeye salmon juveniles were more
abundant in slow (V-I) velocity zones as compared to fast (V-II) zones.
Schmidt and Bingham (1983, Appendix G) compared the frequency of juvenile sockeye salmon
in five major habitat types using Chi-square analyses and found a significant difference.
Sockeye salmon juveniles were frequently found in upland sloughs and side sloughs with large
tributaries. A significant difference was found when all salmon juveniles were combined, with a
relatively high frequency of salmon juveniles being present in side sloughs with large tributaries
and a relatively low frequency of observations in tributary mouths. Schmidt and Bingham
(1983) concluded the habitat types had distinctive salmon juvenile communities.
The 1984 field work (Dugan et al. 1984) tended to support the findings from 1983 (Figure 7.2-6
and Figure 7.2-7). Sockeye salmon juveniles had relative high density distribution (46.5 percent)
in upland sloughs, followed by side sloughs (44.1 percent), side channels (8.6 percent), and
tributaries (0.8 percent). The results of ANOVA tests indicated that macrohabitat type, sampling
period, and mean velocity were significant factors affecting juvenile sockeye salmon CPUE.
Analysis of microhabitat data indicated that sockeye salmon juveniles use deeper, slower water
than the other salmon species; however the authors expressed concern that low sample sizes
resulting from the limited distribution of sockeye salmon juveniles in the Middle Susitna River
reduced the reliability of these results (Suchanek et al. 1984).
7.2.4.2. Overwintering
Roth and Stratton (1985) concluded that most sockeye salmon fry from the Middle Susitna River
emigrated to the Lower Susitna River for overwintering, but a significant number remained and
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overwintered upstream of Talkeetna. Schmidt and Bingham (1983) concluded that Age 0+
sockeye salmon in the Middle Susitna River primarily used upland sloughs and side sloughs for
overwintering and speculated that mainstem or side channel habitats were rarely used. Delaney
et al. (1981) conducted surveys during the March and April 1981 that included several sites in
the Lower Susitna River, but it was ineffective for sockeye salmon with only one juvenile
captured by minnow trap in the mainstem at RM 97.5. Consequently, sockeye salmon
overwintering habitat in the Lower Susitna River is yet undetermined.
7.3. Chum Salmon
7.3.1. Life History Patterns
Chum salmon exclusively outmigrated to marine waters as fry. Consequently, life history
diversity for chum salmon was derived primarily from maturation and spawning at multiple age
classes.
7.3.2. Periodicity
Chum salmon spawning in sloughs of the Middle Susitna River peaked during the last week of
August through the third week of September (Jennings 1985; Section 5.3.4). Chum salmon fry
periodicity was depicted in Table 7.3-1. The timing of chum salmon fry emergence in the
Middle Susitna River is fairly well understood based upon the work by Hoffman et al. (1983)
and Wangaard and Burger (1983). Most chum salmon fry emergence in the Middle Susitna
River occurred in March and was mostly complete by the end of April (Schmidt et al. 1983,
Hoffman et al. 1983), and this was consistent with the size of fry captured in outmigrant traps.
Delaney et al. (1981) sampled Slough 11 and Indian River during March and observed 2,000 pre-
emergent pink salmon, chum salmon, and sockeye salmon alevins. Additional observations on
April 11 indicated nearly all the chum salmon alevins were at the button-up stage. Emerging fry
were first captured on March 23, but it was not reported how many were chum salmon fry. Most
chum salmon fry appeared to emerge at less than 35 mm in size (Roth and Stratton 1985). Fry
were collected at the Talkeetna Station outmigration trap during May 1984 and were thought to
have emerged in April (Roth and Stratton 1985). Sampling for outmigrating fish following ice-
out seldom occurred prior to mid-May or even early June. Therefore, the early portion of the
outmigration season was generally not sampled.
As discussed in Section 6.3.1, all chum salmon outmigrated to the ocean as fry. During 1983 to
1985, incline plan traps were deployed (Roth et al. 1984, Roth and Stratton 1985, Roth et al.
1986). The following discussion focuses on the results from 1984 and 1985 because both catch
rates and cumulative catch were reported. The general pattern of outmigration timing in 1983
was consistent with observations during 1984 and 1985.
Outmigrant trapping began May 14 during 1984 and May 27 during 1985. Outmigration timing
of sockeye salmon fry was influenced by flow and turbidity conditions (Hale 1985). Roth et al.
(1984) found that chum salmon fry catch rates were similarly affected by flow conditions.
During 1984, patterns of outmigration catch rates for chum salmon fry were similar to sockeye
salmon fry. Some chum salmon fry were captured immediately after trap deployment, but peak
capture rates did not occur at Talkeetna Station until mid-June when peak flows occurred (Figure
7.3-1; Roth and Stratton 1985). Also similar to sockeye salmon fry, peak chum salmon fry
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capture rates occurred immediately at the time of trap deployment during late-May 1985 and was
concurrent with the highest flow of the season (Figure 7.3-2; Roth et al. 1986). Roth et al.
(1986) and Roth and Stratton (1985) concluded that about 95 percent of chum salmon fry from
the Middle Susitna River emigrated to the Lower Susitna River by mid-July. The pattern of
chum salmon fry outmigration was similar at the Flathorn Station, even though catch at this
location includes chum salmon production from the Yentna, Deshka, and Talkeetna rivers; most
chum salmon fry have emigrated by the end of June and outmigration is essentially complete by
mid-July.
Moulton (1997) conducted early marine life history studies in northern Cook Inlet from early
June through early September 1993. Chum salmon fry had the second highest catch rate (behind
pink salmon) during the June 3-7 sampling period and increased steadily through June. The
highest chum salmon catch rate occurred during the July 13-15 sampling period. Unlike
Chinook salmon, coho salmon, and sockeye salmon, which passed through relatively quickly,
chum salmon fry tended to have a more extended rearing period and were more widely
distributed in the northern Cook Inlet area. The results of Moulton (1997) are consistent with the
pattern of outmigration by chum salmon fry discerned by the outmigration traps at Flathorn and
Talkeetna Stations reported by Roth and Stratton (1985) and Roth et al. (1984).
7.3.3. Growth
Chum salmon fry appeared to emerge at sizes of less than 35 mm (Roth and Stratton 1985). The
minimum fry size collected at the Talkeetna Station outmigration trap during May 1984 was 32
mm, but the average size was 40.1 mm, indicating that the fry had emerged in April and
experienced growth prior to reaching Talkeetna Station (Roth and Stratton 1985). During 1984,
the average size of outmigrating chum salmon was approximately 40 to 45 mm (Figure 7.3-3;
Roth and Stratton (1985). Roth et al. (1986) reported a similar average size of outmigrants
during 1985. Even during the late May and early June sampling periods of 1984, maximum
chum salmon fry sizes ranged as high as 62 mm in May at the Flathorn Station, and 68 mm in
early June at the Talkeetna Station. Consequently, some chum salmon fry demonstrated
substantial growth prior to or during the outmigration period. The average size of chum salmon
fry that entered northern Cook Inlet during early June 1993 was about 43 mm and the size
distribution widened over the summer sampling period (Moulton 1997). During the July 13-17
sampling period, the size of chum salmon fry in northern Cook Inlet averaged 57.7 mm with a
range of 35 to 75 mm. The change in length frequency was likely due to both early marine
growth of chum salmon fry that entered Cook Inlet as smaller fish and the outmigration of larger
chum salmon fry that reared and grew for a period within their riverine production areas.
7.3.4. Habitat Utilization
7.3.4.1. Open Water Season
Estes and Schmidt (1983) cautioned that interpretation of habitat utilization data for chum
salmon was difficult because it was generally unclear if fry were rearing and feeding in an area
or quickly passing through during outmigration. Analyses of chum salmon fry catch rates within
aggregate zones by Schmidt and Bingham (1983; Appendix F) and Estes et al. (1983) indicated
that sockeye salmon prefer moderately turbid water in low velocity backwaters (aggregate zone
H-II, zones 2, 6, and 7; see Table 3.1-5 and Table 3.1-6 for descriptions). Analysis of the
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aggregate hydraulic or water zones, suggested chum salmon juveniles demonstrated a strong
preference for the mainstem backwater zone (H-II) and avoidance for the mainstem mixing zone
(H-III) and not mainstem backwater (H-I) zones (Schmidt and Bingham 1983 Appendix F).
Schmidt and Bingham (1983, Appendix G) also compared the frequency of juvenile chum
salmon in five major habitat types using Chi-square analyses. The analysis found no significant
difference among tributary mouths, upland sloughs, side sloughs with large tributaries, side
sloughs without large tributaries, and side channels with large tributaries.
Dugan et al. (1984) observed that chum salmon fry were less evenly distributed among the five
major habitat types during 1983 compared to 1982 (Figure 7.3-4 and Figure 7.3-5). Chum
salmon juveniles had relatively high density distribution (59.3 percent) in side sloughs, followed
by tributary mouths (34.1 percent), mainstem side channels (4.1 percent), and upland sloughs
tributaries (2.5 percent). The results of ANOVA tests indicated that macrohabitat type and
sampling period were significant factors affecting juvenile chum salmon CPUE (p<0.10).
Analysis of microhabitat data suggested chum salmon juveniles used relatively shallow, slower
water with large substrate; however the authors expressed concern that low sample sizes reduced
the reliability of the results for chum salmon fry (Suchanek et al. 1984).
7.4. Coho Salmon
7.4.1. Life History Patterns
In the 1980s, there was what appeared to be a high amount of freshwater life history diversity
evident for coho salmon. Scale samples from adult coho salmon collected at fishwheels
indicated that nearly all coho salmon exhibited a stream-type life history pattern and that about
50 to 60 percent outmigrated to the ocean after during their third year of life and 30 to 45 percent
outmigrate during their second year of life (ADF&G 1981, ADF&G 1982c, ADF&G 1984,
Barrett et al. 1985, Thompson et al. 1986). Consequently, most coho salmon juveniles
overwintered in the Susitna River for one or two winters. Plots of the year of life at ocean entry
for adults returning in 1983 and 1984 were typical of other years sampled between 1981 and
1985 (Figure 7.4-1). A small and variable percentage of returning adult coho salmon
outmigrated during their fourth year of life.
7.4.2. Periodicity
Nearly all coho salmon in the Middle Susitna River spawned in tributaries with peak activity
during the last week of July and first week of August (Jennings 1985). Juvenile coho salmon
periodicity is depicted in Table 7.4-1; however, there is some uncertainty for the initiation of fry
emergence and downstream migration. The timing of coho salmon fry emergence in Susitna
River tributaries is poorly understood because of the difficulty of sampling during the spring.
Sampling for outmigrating fish following ice-out seldom occurred prior to mid-May and
frequently could not begin until early June. Consequently there was little sampling occurring at
the time when coho salmon began emerging from the gravel.
Delaney et al. (1981) were unsuccessful at capturing coho salmon fry in Indian River and
Portage Creek during 1981 as part of winter sampling. Sampling did not begin until early June
during 1982 and coho salmon fry were already present (Schmidt et al. 1983). Schmidt et al.
(1983) concluded the surveys conducted during 1981and 1982 would not help in determining the
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time of coho salmon fry emergence, but suggested the wide range of fry sizes observed indicated
emergence occurred over a broad period. Dugan et al. (1984) citing Delaney and Wadman
(1979), indicated coho salmon fry in the Little Susitna River emerge from April through June
based upon observations of fry near spawning areas.
During 1985, sampling in Portage Creek and Indian River began July 6 and coho salmon fry
catch rates peaked in late August (Roth et al. 1986). While the mean length of coho salmon fry
captured at the mouth of Indian River increased from 34.7 mm to 53.2 mm from early July to the
end of September, the minimum size ranged from 30 mm to 38 mm. Fry captured during the
early July period ranged from 30 to 47 mm. Furthermore, the relative small size of some coho
salmon fry throughout the summer supported the hypothesis by Schmidt et al. (1983) that there
was a protracted period of emergence by coho salmon fry.
As discussed in Section 6.4.1, coho salmon smolts outmigrated to the ocean as Age 1+ and Age
2+ fish. During 1983 to 1985, incline plan traps were deployed to provide information on the
timing of smolt migration (Roth et al. 1984, Roth and Stratton 1985, Roth et al. 1986). The
following discussion focuses on the results form 1984 and 1985, because both catch rates and
cumulative catch were reported. The general pattern of outmigration timing in 1983 was
consistent with observations during 1984 and 1985.
In 1985, coho salmon fry outmigration from tributaries, such as Indian River and Portage Creek,
both commenced and peaked in July (Figure 7.4-2; Roth et al. 1986). However, the emigration
from the Middle River tributaries was protracted, with some fry emigrating through October.
Roth and Stratton (1985) observed a similar pattern during 1984. Upon entering the mainstem
Susitna River, coho salmon fry redistributed into sloughs and side channels of the Middle
Susitna River or migrated to the Lower Susitna River (Roth and Stratton 1985, Roth et al. 1986;
Figure 7.4-3). From 1982 to 1985, outmigrant trapping occurred at Talkeetna Station (RM 103)
and Flathorn Station (RM 22.4) during open water periods and demonstrated coho salmon fry
were migrating to the Lower Susitna River throughout the time traps were operating (Schmidt et
al. 1983, Roth et al. 1984, Roth and Stratton 1985, Roth et al. 1986). Roth and Stratton (1985)
suggested that some coho salmon fry either overwintered in Lower Susitna River between the
mouth and Flathorn Station or outmigrated to the ocean as fry. However, based upon the aging
of adult coho salmon returns, very few, if any, coho salmon fry survive and return as adults to
the river.
Based on the capture of a small number of Age 1+ Coho salmon juveniles in the Indian River
during winter sampling (Stratton 1986), some coho salmon fry remain in natal tributaries
throughout their first year of life and overwinter in any available suitable habitat. However, of
the 472 juveniles captured during the winter of 1985 and 1986 in the Indian River, only 3.8
percent were Age 2+ juveniles (Stratton 1986). Consequently, nearly all coho salmon juveniles
emigrate from natal tributaries by the end of their second summer.
Comparison of the pattern in catch rates for coho salmon Age 1+ and 2+ at the Talkeetna and
Flathorn Stations showed a different pattern than fry (Figure 7.4-4 and Figure 7.4-5; Roth et al.
1986, Roth and Stratton 1985). During 1985 coho salmon Age 1+ and 2+ passed the Talkeetna
Station throughout the summer. In contrast, there was large peak during June at the Flathorn
Station and a smaller peak during August. Roth et al. (1986) reported that based upon scale
analysis most of the coho salmon juveniles during the June peak were Age 2+ while those in
August were Age 1+ fish. The pattern of outmigration appeared substantially different during
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1985 with no peak in June. Roth and Stratton (1985) explained that only 44 Age 2+ fish were
captured during 1984 so the pattern of catch represents the redistribution of Age 1+ fish only.
Roth and Stratton (1985) and Roth et al. (1986) concluded that Age 2+ coho salmon smolts
outmigrated during June while Age 1+ coho salmon juveniles redistributed throughout the
summer.
7.4.3. Growth
Growth of coho salmon fry during 1984 and 1985 was similar (Figure 7.4-6). The average size
of fry captured at the Flathorn Station was about 3 to 8 mm larger than fry captured at the
Talkeetna Station and about 10 to 20 mm larger than fry captured at the Indian River during the
same time period. From early June to Late September, average fry length increased at all sites.
During 1984 and 1985, the differences in Age 1+ coho salmon size at Talkeetna and Flathorn
stations appeared less dramatic than for fry. In 1984, mean size of Age 1+ coho salmon
juveniles increased about 45 mm at Talkeetna Station and about 26 mm at Flathorn (Roth and
Stratton (1985). In contrast, growth was somewhat lower and more variable in 1985 with an
increase in average size of about 41 mm at the Talkeetna Station and 7 mm at the Flathorn
Station (Roth et al. 1986). Roth et al. (1986) explained that a number of factors contribute to
spatial and temporal differences in mean length for fry including emergence timing, habitat
quality, and water temperatures. During 1985 Age 2+ coho salmon averaged 132 mm with a
range of 109 to 174 mm (Roth et al. 1986).
7.4.4. Habitat Utilization
7.4.4.1. Open Water Season
Analyses for habitat utilization were more robust for Age 0 fish because few Age 1+ fish were
captured during the 1982 and 1983 field seasons. Analysis of coho salmon juvenile catch rates
during 1982 by Schmidt and Bingham (1983, Appendix F) indicated coho salmon juveniles were
more commonly found in tributary zones (Zones 1 and 2, Table 3.1-5) and downstream of a
tributary mouth (Zone 5). Coho salmon juveniles were more abundant in clear water areas.
When examined using aggregate hydraulic or water zones (Table 3.1-6), coho salmon juveniles
were more prevalent in the tributary water zone (W-I) over mainstem water (W-II) and mixed
water (W-III) zones and a substantial avoidance for the mainstem mixing zone (H-III) compared
to the not mainstem backwater (H-I) and mainstem backwater (H-II) zones. Little difference in
fish abundance was seen in fast (V-II) versus slow (V-I) velocity zones.
Schmidt and Bingham (1983, Appendix G) also compared the frequency of juvenile coho salmon
in five major habitat types using Chi-square analyses and found significant differences. Coho
salmon juveniles were commonly found at side channels with large tributaries (87.5 percent of
samples) and side sloughs with large tributaries (68 percent of samples). Coho salmon were
captured in upland sloughs during about 48 percent of the sampling events. Coho salmon were
rarely observed in tributary mouths or side sloughs without large tributaries (13 percent and 16
percent, respectively).
The 1983 field work (Dugan et al. 1984) partially supported the findings from 1983 (Figure 7.4-8
and Figure 7.4-9). Coho salmon juveniles had relative high density distribution (51 percent) in
tributaries, followed by upland sloughs (35.3 percent). Side channels (4.0 percent) and side
sloughs (9.8 percent) were infrequently used by coho salmon. The ANOVA tests indicated that
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macrohabitat type, sampling period, mean depth, and turbidity were significant factors affecting
juvenile coho salmon CPUE. The major difference in the results from Dugan et al. (1984) and
Schmidt and Bingham (1983) were those regarding the use of tributaries. The results from
Dugan et al. (1984) suggested there was relatively high use while those of Schmidt and Bingham
(1983) suggested there was relatively little. Although the Chi-square analysis in Schmidt and
Bingham (1983, Appendix G) did not result in a statistical association between coho salmon
juveniles and tributary mouths, they concluded in the main body of the report that coho salmon
juveniles are most abundant in clear water tributaries. It is possible the discrepancy in the results
is related to specific tributary habitats. In 1982, Schmidt and Bingham (1983) sampled at three
tributary mouths (Indian River, Portage Creek, Fourth of July Creek), while the 1983 study
included eleven tributaries and included areas upstream of the tributary mouths.
Dugan et al. (1984) and Schmidt and Bingham (1983) each concluded that Coho salmon
juveniles have a preference for areas with clear tributary water sources. They also concluded
that tributaries had a high CPUE because they were the source of coho salmon juveniles prior to
dispersal into side channels and sloughs. Outmigration of Age 0+ coho salmon juveniles from
the tributaries peaked during early July. They suggested that as temperature dropped in
September, coho salmon juveniles depart side channels and tributaries to seek side sloughs and
upland sloughs that provide over-wintering habitat with upwelling groundwater.
7.4.4.2. Overwintering
Little information was available for over winter habitat use by Susitna River coho salmon.
Surveys during the winters of 1980 to 1981 (Delaney et al. 1981) and of 1985 to 1986 (Stratton
1986) provided some information on the winter distribution and habitat characteristics. Delaney
et al. (1981) conducted surveys at 87 sites between Alexander Creek (RM 10.1) to Portage Creek
(RM 148.8). Approximately one third (29) of the sites were standard habitat locations used for
sampling during the open water period. The majority of the sites (53, 61 percent) were in
sloughs or tributaries associated with the Middle Susitna River. Sampling effort was variable
with monthly sampling events occurring from one to seven times between November and May.
During the study 337 coho salmon juveniles were captured, which is approximately half (48
percent) the number of Chinook salmon juveniles captured during the same period. Coho
salmon juveniles were captured at 39 percent of the sites. About half (49 percent) of the catch
occurred at sites in the Middle Susitna River. However, the catch was more evenly distributed in
the Lower Susitna River with juvenile coho salmon captured at 21 of the 34 sites (62 percent).
In contrast, coho salmon juveniles were captured at only 12 of 42 sites (29 percent) in the Middle
Susitna River.
Within the Middle Susitna River, coho salmon juveniles were captured at multiple events,
including winter sampling events, at Slough 8A, Slough 10, Slough 11, and Slough 20.
Although it was only sampled once, Slough 6A had the highest catch rate of 8 Age 1+ fish per
trap-day. Whiskers Creek was sampled twice; no coho salmon juveniles were captured there in
February while a relatively high catch rate of 1.7 Age 1+ and 0.7 Age 2+ coho salmon fry per
trap-day occurred in March. In the Lower Susitna River, coho salmon juveniles were captured
during multiple sampling events at Rustic Wilderness, Sunshine Creek, Montana Creek, and the
mouth of Birch Creek.
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Stratton (1986) studied overwinter habitat use by coho salmon at four locations (Indian River,
Slough 9A, Slough 10, and Slough 22) from October 1985 to April 1986. Fish were captured
using minnow traps and a portion cold branded with a mark unique to the time period and
location of sampling, then released at the capture site. Relatively few coho salmon (472 fish)
were captured compared to Chinook salmon (11,543 fish). This led Stratton (1986) to conclude
that most Age 2+ coho salmon overwintered in the Lower Susitna River. Marks were applied to
393 coho salmon and 7.6 percent were recaptured. All but one recaptured coho salmon were
located in the same site as where they were marked. Relative to Chinook salmon, coho salmon
juveniles more abundant in deeper and slower velocity habitat with cover consisting of debris,
vegetation, and undercut banks. Stratton (1986) also noted that beaver complexes were excellent
overwintering habitat for coho salmon juveniles.
Bigler and Lefesque (1985) captured coho salmon juveniles using fyke nets at Trapper Side
Channel (RM 92.7; April 15 through May 28), Sunset Side Channel (RM 86.9; May 25 through
May 27), Circular Side Channel (RM 75.3; April 30 through May 24) and Birch Creek Side
Channel (RM 88.6; April 30 through May 2) and suggested that these side channels in the Lower
Susitna River were being utilized as overwintering habitat.
7.5. Pink Salmon
7.5.1. Life History Patterns
Pink salmon outmigrate to marine waters as fry and mature as two year old fish. Consequently,
life history diversity for pink salmon is low compared to the other salmon species.
7.5.2. Periodicity
Pink salmon spawning occurred primarily in tributaries to the Susitna River and occasionally in
sloughs. Spawning generally occurred from the last week of July through the first week of
September and peaked during the first two weeks of August (Jennings 1985; Section 5.5.3). Pink
salmon fry periodicity is depicted in Table 7.5-1; however, there is some uncertainty for the
initiation of fry emergence and downstream migration. The timing of pink salmon fry
emergence in the Middle Susitna River is poorly understood. Delaney et al. (1981) sampled
Slough 11 and Indian River during March and observed 2,000 pre-emergent pink salmon, chum
salmon, and sockeye salmon alevins. Additional observations on April 11 indicated about 50
percent of the pink salmon alevins were at the button-up stage. Emerging fry were first captured
on March 23 and most were pink salmon fry.
Based upon the observations by Delaney et al. (1981) and inference from outmigration traps,
most pink salmon fry emergence in the Middle River occurred in March and was mostly
complete by the end of April. Most pink salmon fry appeared to emerge at about 35 mm in size
(Roth and Stratton 1985). The minimum pink salmon fry size collected at the Talkeetna Station
outmigration trap during May 1984 was 29 mm, but the average size was 36 mm, suggesting that
most of the fry had emerged in April (Roth and Stratton 1985). Sampling for outmigrating fish
following ice-out seldom occurred prior to mid-May or even early June. Therefore, part of the
outmigration season was not sampled.
As discussed in Section 6.5.1, all pink salmon outmigrate to the ocean as fry. During 1983 to
1985, incline plan traps were deployed to produce information on the timing of smolt migration
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(Roth et al. 1984, Roth and Stratton 1985, Roth et al. 1986). The following discussion focuses
on the results from 1984 and 1985, because both catch rates and cumulative catch were reported.
The general pattern of outmigration timing in 1983 was consistent with observations during 1984
and 1985.
Outmigrant trapping began May 14 during 1984 and May 27 during 1985. Pink salmon were
present in the catch immediately following deployment in both years. Peak capture rates did not
occur at Talkeetna Station until mid-June when peak flows occurred (Figure 7.5-1; Roth and
Stratton 1985). In 1985, peak pink salmon fry capture rates occurred in early June, which was
concurrent with the highest flow of the season (Figure 7.5-2; Roth et al. 1986). Roth et al.
(1986) and Roth and Stratton (1985) concluded that about 95 percent of pink salmon fry from the
Middle Susitna River emigrated to the Lower Susitna River by mid-July. The pattern of pink
salmon fry outmigration was similar at the Flathorn Station and included pink salmon production
from the Yentna, Deshka, and Talkeetna rivers; most pink salmon fry had emigrated by the end
of June, and outmigration was essentially complete by mid-July.
Moulton (1997) conducted early marine life history studies in northern Cook Inlet from early
June through early September 1993. Pink salmon fry captures were greatest in mid-June and
then declined. Similar to Chinook salmon, coho salmon, and sockeye salmon, pink salmon fry
tended to move out of the area quickly during June. However, during July pink salmon fry
demonstrated some growth, indicating that many were remaining in the area to rear. These
results were consistent with the pattern of outmigration reported by Roth and Stratton (1985) and
Roth et al. (1984).
7.5.3. Growth
Most pink salmon fry appeared to emerge at about 35 mm in size (Roth and Stratton 1985). The
average size of pink salmon fry collected at the Talkeetna Station outmigration trap during 1984
was 36 mm with a range of 29 to 53 mm (Roth and Stratton 1985). This was similar to the size
of pink salmon fry collected at the Flathorn Station, which had mean size of 34 mm and range of
25 to 46 mm. Sizes were similar during 1985, with an average pink salmon fry length of 37 mm
and a maximum size of 48 mm (Roth et al. 1986). The average size of pink salmon fry entering
northern Cook Inlet during early June 1993 was 35.9 mm (Moulton 1997), which indicates that
pink salmon fry did not grow a substantial amount in the Susitna River prior to outmigration into
nearshore marine waters.
7.5.4. Habitat Utilization
7.5.4.1. Open Water Season
Studies conducted during the 1980s provided no information on habitat use by pink salmon fry
during the spring outmigration. Based upon the size of fry collected from outmigration traps
(Roth ad Stratton 1985, Roth et al. 1986) and the size of fry collected in northern Cook Inlet
(Moulton 1993), pink salmon outmigrated from the Susitna River shortly after emergence with
little use of rearing habitat. Schmidt and Bingham (1983) suggested that turbidity may have
been an important factor during the pink salmon outmigration, because it could provide
protection from visual predators such as other fish and birds.
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7.6. Juvenile Salmon Diet
Riis and Friese (1978) examined the stomach contents of 377 Chinook salmon, 53 sockeye
salmon, and 62 coho salmon juveniles collected from 25 mainstem Susitna locations in the lower
and middle river plus several tributary streams (Whiskers Creek, Fourth of July Creek, Chase
Creek, McKenzie Creek. Adult aquatic insects accounted for the highest proportion by volume
of food items for Chinook salmon and coho salmon juveniles during the summer and fall (Figure
7.6-1). In contrast, immature insects (primarily diptera larvae) were the highest proportion for
sockeye salmon during the summer, but adult life stages represented the highest volume during
the fall. Cladocera were also part of the sockeye salmon diet at three of the sloughs sampled.
Stomach contents volumes or proportions were not reported by taxon; however, table notes
suggested that adult diptera were the predominant adult life stage found within the adult insect
category.
Schmidt et al. (1983) investigated the stomach contents of 313 Chinook salmon, 171 coho
salmon, and 116 sockeye salmon juveniles collected from four sloughs (Sloughs 8A, 11, 20, and
21) and two tributary streams (Fourth of July Creek, and Indian River). Data was reported by
prey item taxon and summarized for each salmon species, site, and date. Diptera larvae, pupae,
and adults were the most frequently consumed food items, but emphemeroptera (mayflies) and
plecoptera (stoneflies) were also represented in the diets. Terrestrial insects were also commonly
found and represented up to 29 percent of the items consumed. Similar to Riis and Fiese (1978),
sockeye salmon were found to consume copepods and cladocerans in some locations. Schmidt et
al. (1983) calculated electivity indices that proportionally compared prey species in stomach
contents to drift net collections and benthic samples. The results indicated Chinook salmon,
coho salmon, and sockeye salmon juveniles had been selecting for chironomidae larvae.
Hansen and Richards (1985) examined 72 juvenile Chinook salmon stomachs for food content.
Chinook salmon food items were derived from eleven insect orders and one non-insect order.
On a numerical basis larval diptera were the most frequently consumed food item (46 percent)
and burrowers were the frequently consumed guild (87 percent; Figure 7.6-2). Although
dipteran flies were the most frequently consumed prey item, they are also relatively small.
Hansen and Richards (1985) suggested that plecopterans and ephemeropterans were likely more
important to the diet of juvenile Chinook salmon than dipteran flies because they are on the order
of ten times larger than dipterans.
8. NON-SALMONIDS AND RESIDENT FISHES
During 1981 and 1982 Su-Hydro Aquatic Studies, surveys were conducted to better understand
the distribution and relative abundance of resident fish and the anadromous non-salmonids in the
Upper, Middle, and Lower Susitna River (Delaney et al. 1981, Delaney et al. 1981b, Sautner and
Stratton 1983, Schmidt et al. 1983). During 1983 and 1984, ADF&G monitored changes in the
fish community and movement of floy-tagged fish at thirteen index sites, estimated population
sizes at five sites, and conducted radio-tracking on rainbow trout and burbot (Sundet and Wenger
1984, Sundet and Pechek 1985). A winter study was conducted during 1984 – 1985 that focused
primarily on the radio-tracking of rainbow trout, burbot, and Artic grayling. During 1982 and
1983, the AA component to the Su-Hydro Aquatic studies conducted surveys for spawning
eulachon and Bering cisco (Coregonus laurettae)in the Lower Susitna River and examined the
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characteristics of eulachon spawning habitat (ADF&G 1982c, ADF&G 1984, Vincent-Lang and
Queral 1984).
8.1. Fish Assemblage
Historically, the Susitna River basin included at least 20 species of fish (Table 8.1-1). With the
exception of northern pike, all fish are considered native to the basin. The diversity of the fish
community was highest in the Lower Susitna River and declined in an upstream direction. A
large decline in diversity occurred at Devils Canyon because of insurmountable rapids.
Data reported in Schmidt et al. (1983) provides a representative depiction of the resident fish
community at 17 DFH locations (Table 3.1-4) within the Middle and Lower Susitna River
segments. During 1982 sampling generally occurred twice per month (bi-weekly) at each DFH
site during the open water season from June through September (Table 8.1-2). Sampling
methods included beach seines, minnow traps, trot lines, backpack electrofishing, boat
electrofishing, set gillnets, hook and line, unspecified fish traps, hoop nets, and dip nets.
Sampling also occurred at some sites during late-May, early October, and during winter.
Sampling for resident fish also occurred in 1981, 1983, 1984, and winter 1984/1985, but only
summary data is available for 1983 to1985 surveys (Schmidt et al. 1984, Schmidt et al. 1985,
Sundet 1986). Catch per unit effort data is available for 44 sites surveyed during 1981 (Delaney
et al. 1982), but with the exception for minnow traps and trot lines, sampling was less systematic
than conducted during 1982 at the DFH sites. Furthermore, actual catch and effort data were not
reported for 1981 surveys only catch per unit effort for sites with catch greater than zero during
one or more sampling periods. Despite the differences in survey site locations, level of effort
among the gear types, and level of reporting detail, summary information from Delaney et al.
(1984), Schmidt et al. (1984), and Schmidt et al. (1985) support the conclusion that 1982 surveys
were representative of the general distribution and relative abundance of resident fish species in
the Susitna River mainstem during the early 1980s.
8.2. Distribution, Abundance, and Habitat Utilization
8.2.1. Susitna River Downstream of Devils Canyon
Jennings (1985) provided a concise summarization of the distribution of resident fish in the
Middle Susitna River. Portions of the text in Sections 7.2.1.1 through 7.2.1.15 are quotes taken
from that report with minor corrections to some citations.
Eulachon are an important forage species for beluga whale. Distribution, life history
characteristics, and habitat utilization information on eulachon are summarized in the beluga
whale technical memorandum (HDR 2012A). Consequently, information on eulachon will only
be briefly discussed below.
8.2.1.1. Rainbow Trout
Jennings (1985) provided the following summarization of rainbow trout distribution and
abundance in the middle Susitna River segment.
“Rainbow trout occur throughout the Susitna Basin below Devil Canyon (Schmidt
et al. 1983). Upstream from Talkeetna, they mainly use tributaries for spawning
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and rearing, while overwintering occurs primarily in the mainstem (Schmidt et al.
1984).
Upstream of the Chulitna River confluence (RM 98.6), rainbow trout move into
tributaries to spawn in late May and early June (Schmidt et al. 1984). Whiskers
Creek (RM 104.4), Lane Creek (RM 113.6) and Fourth of July Creek (RM 131.1)
are the major spawning areas in this river reach, whereas the larger tributaries
(Indian River and Portage Creek) are of lesser importance (Schmidt et al. 1984).
Both sexes mature by Age 5+ (Schmidt et al. 1984).
There is a post-spawning movement from spawning areas to feeding areas
(Schmidt et al. 1984). These feeding areas may be located in the same tributaries
in which spawning occurred, or in other tributaries and at tributary mouths
(Schmidt et al. 1983, Schmidt et al. 1984). During August and September
rainbow trout can be found in sloughs and at tributary mouths that are occupied
by adult salmon (Schmidt et al. 1983, Schmidt et al. 1984). It is suspected that
rainbow trout feed on salmon eggs at these sites (Schmidt et al. 1984).
Juvenile rainbow trout rear mainly in tributaries (Schmidt et al. 1983, Schmidt et
al. 1984). Some juveniles also rear in the mainstem and sloughs, but the use of
these habitats appears to be limited (ADF&G 1983b, Schmidt et al. 1984).
Fourth of July Creek (RM 131.1) is an important rearing area for juvenile
rainbow trout (Schmidt et al. 1984).
In the fall, rainbow trout move out of tributaries into the mainstem to overwinter
(Schmidt et al. 1983, Schmidt et al. 1984). By early December in 1983, most
radio-tagged rainbow trout were located in mainstem areas that were not
influenced by tributary inflow (Schmidt et al. 1984).
Based on recaptures from three years of tagging (1981-1983), the population size
of rainbow trout in the Talkeetna-to-Devil Canyon reach was estimated to be
about 4,000 fish (greater than 150 mm in length; Schmidt et al. 1984). This
estimate should be viewed as an approximation because it does not account for
annual recruitment, mortality or emigration (Schmidt et al.1984).”
During 1982, rainbow trout were widely distributed at the 17 DFH sites (Figure 8.2-1). Rainbow
trout were captured at all DFH sites except Whitefish Slough. Rainbow trout catch was
frequently higher and more consistent at DFH sites associated with tributary streams (Lane
Creek and Slough 8, 4th of July Creek, Whiskers Creek and Slough) and clearwater sloughs
(e.g., Slough 6A and Slough 8A). Boat electrofishing and trotlines were the most effective
capture methods, accounting for 43.4 percent and 33.2 percent of the 205 rainbow trout captured,
respectively. However, rainbow trout were captured by a wide variety of gear types.
8.2.1.2. Arctic Grayling
Jennings (1985) provided the following summarization of rainbow trout distribution and
abundance in the middle Susitna River segment.
“Arctic grayling are found throughout the Susitna Basin (Schmidt et al. 1983). In
the Ta1keetna-to-Devil Canyon reach, Arctic grayling primarily use mainstem
habitats for overwintering and tributaries for spawning and rearing (Schmidt et
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al. 1983, Schmidt et al. 1984).Upstream of Talkeetna, Arctic grayling move into
tributaries to spawn in May and early June (Schmidt et al. 1983, Schmidt et al.
1984).High catches occurred in Whiskers Creek Slough (RM 101.2), Lane Creek
(RM 113.6), Fourth of July Creek (RM 131.1), Indian River (RM 138.6), Jack
Long Creek (RM 144.5) and Portage Creek (RM 148.8) in 1982 and 1983
(Schmidt et al. 1984). Although these tributaries have not been identified as
spawning areas, they are likely candidates. Spawning may also occur in the
mainstem. In 1983, it was suspected that spawning occurred at or near RM 150.1
(Schmidt et al. 1984). After spawning, most adults and juveniles remain in
tributaries or move to tributary and slough mouths until early September
(Schmidt et al. 1983, Schmidt et al. 1984). Some juvenile fish rear in mainstem
areas (Schmidt et al. 1983, Schmidt et a1. 1984). These juveniles may be
displaced from tributary habitat by the territorial behavior of older, larger fish
(Schmidt et al. 1983, Schmidt et al. 1984). During September, Arctic qray1ing
move into the mainstem from tributaries (Schmidt et al. 1983, Schmidt et al.
1984). It is suspected that this movement to the mainstem is for overwintering,
however specific areas have not been identified (Schmidt et al.1984). Some fish
may use the larger, deeper pools in Portage Creek for overwintering (Schmidt et
al. 1984).”
During 1982, Arctic grayling were captured at 15 of the 17 DFH sites (Figure 8.2-2). Arctic
grayling catch was highest at tributary mouths of Indian River, Portage Creek, 4th of July Creek,
and Whiskers Creek and Slough. Boat electrofishing and backpack electrofishing were the most
effective capture methods, accounting for 70.6 percent and 13.7 percent of the 520 Arctic
grayling captured, respectively. Arctic grayling were captured by a wide variety of gear types.
8.2.1.3. Burbot
Jennings (1985) provided the following summarization of burbot distribution and abundance in
the middle Susitna River segment.
“Burbot occur throughout the Susitna River basin (Delaney 1981a, Schmidt et al.
1983). Burbot appear to be more abundant downstream from the Chulitna River
confluence (RM 98.6; Schmidt et at. 1984). Burbot are associated almost
exclusively with the mainstem and mainstem-influenced areas.
Burbot apparently move to spawning areas in the winter and then disperse to
feeding areas after spawning is completed (Schmidt et al. 1983, Schmidt et al.
1984). Other than these migrations, burbot are generally sedentary (Schmidt et
al. 1983). Burbot spawning takes place from mid-January to early February in
mainstem-influenced areas (Schmidt et al. 1983, Schmidt et al. 1984). Tributary
and slough mouths are thought to be important areas of spawning, as are
mainstem areas with groundwater upwelling (Schmidt et al. 1983, Schmidt et al.
1984). Spawning areas have not been located in the Talkeetna-to-Devil Canyon
reach (Schmidt et al. 1984). Downstream of Talkeetna, the mouth of the Deshka
River (RM 40.5) is a known spawning area (Schmidt et al. 1983).
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Due to the limited catch data, juvenile rearing areas are unknown. It is suspected
that juvenile burbot rear in the mainstem, tributary and slough mouths, and
clearwater sloughs (Delaney 1981a, 1983b).
In 1983, 15 burbot were estimated to occur between RM 138.9 and140.1 (Schmidt
et al. 1984). This population estimate should be viewed as an approximation
because few fish were caught during this study (Schmidt et al. 1984). However, it
appears that the burbot population size in the middle Susitna River is low.”
During 1982 relatively low numbers of burbot were captured at all 17 DFH sites in the Lower
and Middle Susitna River (Figure 8.2-3; Schmidt et al. 1983). Most burbot (69.3 percent of 155
fish) were captured by trotline. However, 18 burbot were captured from three hauls of a beach
seine at Slough 9 during late June 1982, which was the maximum burbot catch at any site and
period (Figure 8.2-3). CPUE for burbot captured by trotline at the DFH sites averaged 0.4 fish
per trotline- day and the maximum for individual sites/periods was 2.7 fish per trotline-day
(Figure 8.2-4).
8.2.1.4. Round Whitefish
Jennings (1985) provided the following summarization of round whitefish distribution and
abundance in the middle Susitna River segment.
“Round whitefish occur throughout the Susitna River drainage (Delaney et al.
1981a). Downstream from Devil Canyon, they appear to be more abundant in the
middle river reach (Schmidt et al. 1983). Within this reach, round whitefish are
most numerous between RM 132.6 and 150.1 (Schmidt et al. 1984). Round
whitefish were found in tributaries and sloughs more often than mainstem areas
in 1982 and 1983 (Schmidt et al.1984). The mainstem is used for some spawning
and juvenile rearing, and as a migrational corridor. During September, there is
an upstream migration of round whitefish that is thought to be associated with
spawning (Schmidt et al. 1983). This species spawns in the mainstem and at
tributary mouths in October (Schmidt et al. 1983, Schmidt et al. 1984). During
1981 through 1983, nine spawning areas were identified upstream of Talkeetna.
Mainstem sites were: RM 100.8, 102.0, 102.6, 114.0, 142.0 and 147.0 (Schmidt et
al. 1984). Round white fish may also spawn in tributaries, such as Indian River
and Portage Creek (Schmidt et al. 1984). Juvenile round whitefish rear mainly in
the mainstem and sloughs (Schmidt et al. 1983, Schmidt et al. 1984). Slow
velocities and turbid water are apparently preferred (Schmidt et al.1984).
Overwintering areas of round whitefish have not been identified (Schmidt et al.
1983).”
During the 1982 surveys, round whitefish were captured at all sites by a variety of gear types
(Figure 8.2-5). Round whitefish catch was highest mouths of Portage Creek, Indian Creek, 4th of
July Creek, and at Slough 9. Boat electrofishing and beach seines were the most effective
capture methods and accounted for 59.7 percent and 27.8 percent of the 890 round whitefish
captured, respectively.
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8.2.1.5. Humpback Whitefish
Jennings (1985) provided the following summarization of round whitefish distribution and
abundance in the middle Susitna River segment.
“Humpback whitefish are found downstream of Devil Canyon between RM 10.1
and 150.1 (Schmidt et al. 1984). They appear to be more abundant downstream
from the Chulitna River confluence (RM 98.6; Schmidt et al. 1984). In the
Talkeetna-to-Devil Canyon reach, tributary and slough mouths are used by adults
most frequently, with the mainstem serving mainly as a migrational corridor
(Schmidt et al. 1983, Schmidt et a1. 1984). Due to low catches of humpback
whitefish, little is known of their overwintering, spawning and juvenile rearing
areas (ADF&G 1983b, Schmidt et al. 1984). It is suspected that they spawn in
tributaries during October (Schmidt et al. 1984).”
During the 1982 surveys, humpback whitefish were captured at 12 of the 17 DFH sites in low
numbers (Figure 8.2-6). Humpback whitefish catch was highest at the mouth of Portage Creek
and at Sunshine Creek and Side Channel (12 fish each). Boat electrofishing was the most
effective capture methods and accounted for 96.1 percent of the 52 humpback whitefish
captured.
8.2.1.6. Longnose Sucker
Jennings (1985) provided the following summarization of longnose sucker distribution and
abundance in the middle Susitna River segment.
“Longnose suckers occur throughout the Susitna Basin (Schmidt et al. 1984,
Sautner and Stratton 1984). They appear to be more abundant downstream of the
Chulitna River confluence (RM 98.6; Schmidt et al. 1984). In the Talkeetna-to-
Devil Canyon reach (RM 98.6-152), longnose suckers are primarily associated
with tributary and slough mouths, although the mainstem is also used throughout
the open-water season (Schmidt et al. 1983, Schmidt et al.1984). The major
overwintering and juvenile rearing areas of this species are unknown (Schmidt et
al. 1983). The mouths of Trapper Creek (RM 91.5) and Sunshine Creek and side
channel (RM 85.7) are known spawning areas (Schmidt et al. 1983).”
During the 1982 surveys, longnose suckers were captured at all sites by a variety of gear types
(Figure 8.2-7). Longnose sucker catch was highest at Rabideaux Creek and Slough (68 fish),
Whiskers Creek and Slough (56 fish), Sunshine Creek and Side Channel (55 fish), and Slough
8A (51 fish). Boat electrofishing and beach seines were the most effective capture methods and
accounted for 74.3 percent and 12.3 percent of the 447 longnose suckers captured, respectively.
8.2.1.7. Dolly Varden
Jennings (1985) provided the following summarization of Dolly Varden distribution and
abundance in the middle Susitna River segment.
“Dolly Varden occur throughout the Susitna Basin (Schmidt et al.1984). In the
Talkeetna-to-Devi1 Canyon reach, Dolly Varden are found primarily in the upper
reaches of tributaries and at tributary mouths (Schmidt et al. 1983, Schmidt et al.
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1984). They apparently use the mainstem for overwintering (Schmidt et al.1984).
Spawning and juvenile rearing areas are suspected to be in tributaries (Schmidt
et al. 1983). The population size of Dolly Varden in the Talkeetna-to-Devil
Canyon reach appears to be low and they are apparently more abundant
downstream from the Chulitna River confluence (RM 98.6; Schmidt et al. 1984).”
During the 1982 surveys, Dolly Varden were captured in low numbers at nine of the 17 DFH
sites by a variety of gear types (Figure 8.2-8). Dolly Varden catch was highest at Lane Creek
and Slough 8 (8 fish). Boat electrofishing and trotlines were the most effective capture methods
and accounted for 40.0 percent and 36.0 percent of the 25 Dolly Varden captured, respectively.
8.2.1.8. Arctic Lamprey
Jennings (1985) provided the following summarization of Arctic lamprey distribution and
abundance in the middle Susitna River segment.
“Arctic lamprey have been found in the: Susitna River as far upstream as Gash
Creek (RM 111.5), however they are more abundant downstream of RM 50.5
(Schmidt 1983, Schmidt et al.1984). Most fish have been found in tributaries and
tributary mouths (Schmidt et al. 1983, Schmidt et al. 1984).”
Arctic lamprey were captured at three DFH sites during 1982: Birch Creek and Slough (31 fish),
Sunshine Creek and Side Channel (1 fish), and Whiskers Creek and Slough (3 fish). Capture
occurred by backpack electrofishing (30 fish) and minnow traps (5 fish).
8.2.1.9. Threespine Stickleback
Jennings (1985) provided the following summarization of threespine stickleback (Gasterosteus
aculeatus) distribution and abundance in the middle Susitna River segment.
“Threespine stickleback have been caught: in the Susitna River as far upstream
as RM 146.9, but they are more abundant downstream of the Chulitna River
confluence (RM 98.6; Schmidt et al. 1983, Schmidt et al. 1984). Spawning and
juvenile rearing apparently occur in tributary and slough mouths (Schmidt et al.
1983). Over-wintering areas of this species are unknown (Schmidt et al. 1983).”
During 1982, threespine sticklebacks were captured at the six DFH sites from Goose Creek 2 and
Side Channel to Whiskers Creek and Slough by a variety of methods (Figure 8.2-9). Beach
seines and minnow traps were the most effective capture methods with each accounted for 41.9
percent of the 210 threespine sticklebacks captured, respectively. However, most of the beach
seine catch, 52 of 88 fish, came from a single haul at Whitefish Slough during early August.
8.2.1.10. Bering Cisco
Jennings (1985) provided the following summarization of Bering cisco distribution and
abundance in the middle Susitna River segment.
“Bering cisco occur mainly downstream of the Chulitna River confluence (RM
98.6) in the Susitna River (Barrett et al.1984). In 1981 and 1982, the major
spawning areas for this species were in the mainstem between PM 75 and 85
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(Barrett et al. 1984). In 1982, most spawning fish were Age 5 that had gone to
the ocean for rearing in their first summer (ADF&G 1982c).”
Information gathered on Bering cisco during the 1980s was focused on identification of
spawning areas and periodicity. Bering cisco were not captured at any of the DFH sites surveyed
during 1982 (Schmidt et al. 1983). Barrett et al. (1983) reported the capture of Bering cisco at
fishwheels located at Susitna Station (RM 26; 42 fish), Yentna Station (RM 30.1, TRM 4.0; 4
fish), and Sunshine Station (RM 80; 165 fish). Catch of Bering Cisco at Sunshine Station began
in late-August and peak in late-September, just prior to demobilizing the fishwheels (Figure 8.2-
10). During 1982 spawning ripe females were observed beginning October 2 and through the
end of surveys on October 13. Spawning locations were identified at a shoal between RM 76.8
to 77.6 and near RM 81.2. Barrett et al. (1983) reported that no Bering cisco spawning was
observed at any of the 397 main channel sites surveyed between RM 98.5 and RM 150. In
addition, only one Bering cisco was captured upstream of the Three Rivers confluence at RM
101.9.
8.2.1.11. Eulachon
Jennings (1985) provided the following summarization of Bering cisco distribution and
abundance in the middle Susitna River segment.
“Eulachon occur in the Susitna River as far upstream as RM 50.5, but are more
abundant downstream of RM 29 (Barrett et al.1984). Because eulachon are not
found in the middle reach of the Susitna River, they are not discussed in great
detail. Information on preferred habitat and life history information can be found
in reports by Barrett et al. (1984) and Vincent-Lang and Queral (1984).
Eulachon enter the Susitna River in two runs (Barrett et al. 1984). The first run
enters the river during the last two weeks of May, while the second run follows
during the first two weeks of June (Barrett et al.1984). Fish from both runs
spawn in the mainstem (Barrett et al. 1984). The first-run population size is likely
several hundred thousand fish, while the second run is probably several million
fish (Barrett et al. 1984). In 1982, most returning adults were Age 3 that had
gone to the ocean for rearing in their first summer (ADF&G 1982c).”
Similar to Bering cisco, information gathered on eulachon during the 1980s was focused on
identification of spawning areas and periodicity. Eulachon were not captured at any of the DFH
sites surveyed during 1982 (Schmidt et al. 1983). Barrett et al. (1983) captured eulachon in the
estuary on May 16, 1982, which was the first ice-free day of the year. Based upon the gillnet
catch rates, Barrett et al. (1983) concluded that eulachon enter the river in two runs. Surveys
during 1983 confirmed this pattern of entry into the Susitna River (Figure 8.2-11). Barrett et al.
(1984) concluded that eulachon migrate up to about 50 miles in the Susitna River, but spawning
occurs within 29 miles. In addition, Barrett et al. (1984) concluded that spawning begins within
about five days of entering the river.
Vincent-Lang and Queral (1984) investigated spawning habitat characteristics for eulachon,
particularly for water depth, velocity, and substrate. They concluded that eulachon spawn in
turbid water along shoreline margins over a broad range of these parameters (Figure 8.2-12).
While gravel/rubble was the most commonly used spawning substrate, they also observed
spawning in areas that were 100 percent silt and others that were a mix of silty sand mixed with
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gravel and rubble. Water temperatures during spawning ranged from 6.2°C to 11.2°C and
averaged 8.5°C during 1982 and 8.3°C during 1983 (Vincent-Lang and Queral (1984).
Additional details on the distribution, life history characteristics, and habitat utilization of
eulachon are summarized in the beluga whale technical memorandum (HDR 2012a).
8.2.1.12. Sculpin
Jennings (1985) provided the following summarization of sculpin distribution and abundance in
the middle Susitna River segment.
“Slimy sculpin occur throughout the Susitna River drainage (Delaney et al.
1981c, Schmidt et al. 1983). They are most abundant in tributaries and tributary
mouths, although the mainstem is also used (Schmidt et al. 1983). Sculpin in the
Susitna River are sedentary with spawning, juvenile rearing and adult movements
confined to a limited area (Schmidt et al. 1983). In addition to slimy sculpin,
other species of sculpin may occur in the lower Susitna River (Delaney et al.
1981a).”
During 1982, slimy sculpin were captured at all 17 DFH sites using a variety of gear (Figure 8.2-
13). Catch was highest at Whiskers Creek and Slough (107 fish), Birch Creek and Slough (81
fish), Lane Creek and Slough (59 fish), and Sunshine Creek and Slough (56 fish). Backpack
electrofishing and beach seines were the most successful capture methods that accounted for 43.3
percent and 29.1 percent of the 533 slimy sculpin captured, respectively.
8.2.1.13. Lake Trout
Jennings (1985) provided the following summarization of lake trout (Salvelinus namaycush)
distribution and abundance in the middle Susitna River segment.
“Lake trout occur throughout the Susitna Basin primarily in larger, deeper lakes.
Occasionally they can be found in the inlet or outlet streams of these lakes. Lake
trout have not been captured in the mainstem-influenced areas of the Susitna
River below Devil Canyon (Delaney et al. 1981c, Schmidt et al. 1983; Schmidt et
al.1984).” Northern Pike
Please see Section 8.4, Invasive Fish Species.
8.2.1.14. Ninespine stickleback
Jennings (1985) provided the following summarization of ninespine stickleback (Pungitius
pungitius) distribution and abundance in the middle Susitna River segment.
“Ninespine stickleback are apparently rare in the Susitna River. This species has
been captured in the vicinity of the Deshka River (RM 40.5; ADF&G Su Hydro,
unpublished data).”
8.2.2. Susitna River Upstream of Devils Canyon
Surveys were conducted in the Susitna River and tributaries upstream of Devils Canyon during
1981 and 1982 (Delaney et al. 1981c, Sautner and Stratton 1983). During 1981, eight tributary
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streams were selected for surveys: Fog Creek (173.9), Tsusena Creek (RM 178.9), Deadman
Creek (RM 183.4), Watana Creek (RM 190.4), Kosina Creek (RM 202.4), Jay Creek (RM
203.9), Goose Creek (RM 224.9), and Oshetna River (RM 226.9; Delaney et al. 1981c). Each
tributary was surveyed for fish in up to 5 segments (0 to 500, 1000 to 1500, 2000 to 2500, 2500
to 3000, 4000 to 4500). The lowermost sites included sampling immediately upstream and
downstream of the tributary confluence in the mainstem river. In some tributaries additional
sites were sampled up to the anticipated elevation of the impoundment. Sites were sampled
monthly during the open water period using hook and line, minnow traps, trotlines, beach seines,
backpack electrofishing, and variable mesh gillnets. Not all collection methods were used at
each site. Detailed results were reported for Arctic grayling, burbot, round whitefish, longnose
sucker, sculpin, and lake trout. In addition to these species one humpback whitefish (347 mm
fork length) was captured at the mouth of Kosina Creek and one Dolly Varden (235 mm) was
captured at the mouth of Fog Creek.
The 1982 study was focused on: 1) measuring tributary habitat and water quality characteristics
within and upstream of the proposed inundation zone; and 2) collecting additional biological
information on Arctic grayling, lake trout, and fish communities at seven mainstem slough areas.
These areas included: Site No. 1 (RM 191.5), Site No. 2 (RM 191.5), Watana Creek Slough (RM
194.1), Site No. 3 (RM 197.8), Site No. 3A (RM 201.6), Site No, 4 (RM 201.2), and Site No. 5
(Lower Jay Creek Slough, RM 208.1; Sautner and Stratton 1983) and Sally Lake.
8.2.2.1. Arctic Grayling
Arctic grayling is one of the most abundant fish in Upper Susitna River tributaries. Delaney et
al. (1981c) reported the capture of 3,313 Arctic grayling during 1981, and Sautner and Stratton
(1983) reported the capture of 4,367 Arctic grayling during 1982. Hook and line was a very
successful capture method in tributary streams during 1981 and 1982 with a median catch rate of
6.0 fish per hour and a maximum rate of 23.2 fish per hour.
During 1981, catch rates by anglers were highest for Kosina and Jay creeks (Figure 8.2-14).
Angler catch rates increased from May (6.1 fish per hour) to July (8.1 fish per hour) and then
declined in August (4.5 fish per hour) and September (4.0 fish per hour). A Chi-square analysis
on the number of fish captured by angling indicated there were significant differences in catch
between the tributaries.
For many sites and sampling periods, hook and line catch rates were somewhat higher in 1982
compared to 1981. During 1982, hook and line catch rates were highest for the Oshetna River
(11.1 fish per hour) and Kosina Creek (10.4 fish per hour; Figure 8.2-14). Catch rates were
highest in July (12.8 fish per hour) and August (13.4 fish per hour).
Observations of spent Arctic grayling with frayed fins during late May and early June suggested
that most spawning had already been completed; however two ripe males were collected on May
22 (Delaney et al. 1981c). Based upon this information and experience from other areas,
Delaney et al. (1981c) suggested that Arctic grayling spawning likely occurs during late-April to
mid-May. Arctic grayling fry and Age 1+ were observed in the slough near Jay Creek. Fry were
20 to 22 mm in June, 24 to 45 mm in July, and 47 to 60 mm in September. Age 1 Arctic
grayling were 54 mm in May, 75 to 95 mm in June, and 84 to 98 mm in July.
In 1981, floy tags were attached to 2,511 Arctic grayling and 268 tagged fish were recaptured
(Delaney et al. 1981c). In 1982, 3,560 Arctic grayling were tagged and 350 tagged fish were
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recaptured (Stratton 1983). Population sizes were estimated using the Schnabel method from the
mark-recapture data with a total Upper Susitna River estimate of 10,279 fish with a 95 percent
confidence interval of 9,194 to 11,654 fish (Table 8.2-1). Total Arctic grayling population size
during 1982 was 16,346 fish (Sautner and Stratton (1983). Arctic grayling abundance was
highest in Kosina Creek and lowest in Fog Creek. Tagged Arctic grayling moved around
considerably (Delaney et al. 1981c Sautner and Stratton 1983). In 1981, 243 fish were
recaptured within the same tributary in which they were tagged. Of these fish, 50 moved up to 2
miles downstream and 69 fish moved up to 12 miles upstream. Approximately half (124 fish) of
the recaptured tagged fish remained at the tagging location, and nine percent were recaptured in a
tributary or tributary mouth different from the tagging location. The longest movement was 34.5
miles from Goose Creek to Watana Creek. During 1982, Arctic grayling tagged in tributaries
made movements of up to 30.2 miles, and similar to 1981, a substantial proportion of the
recaptured fish (12.0 percent) were recaptured in a different stream than tagged (Sautner and
Stratton 1983).
In 1982, relatively few Arctic grayling were captured (Sautner and Stratton 1983). Among the
seven mainstem slough sites that were sampled, only 21 arctic grayling and, and all were
captured at the Watana Creek Slough. Sampling in Sally Lake resulted in the capture of 42
Arctic grayling.
8.2.2.2. Dolly Varden
Dolly Varden were also present in the Upper Susitna River (Delaney et al. 1981b, Sautner and
Stratton 1983) but were relatively uncommon compared to Arctic grayling. Delaney et al. (1981)
captured one Dolly Varden (235 mm length) at the mouth of Fog Creek. Sautner and Stratton
(1983) captured 16 Dolly Varden at five of the tributaries sampled during 1982 (Cheechako,
Devil, Watana, Jay, and upper Deadman creeks). All of the Dolly Varden captured during 1982
in the Upper Susitna River were small (120 to 205 mm) and considered stunted.
8.2.2.3. Burbot
Burbot were present throughout the mainstem Upper Susitna River to at least the Oshetna River
(Delaney et al. 1981b, Sautner and Stratton 1983). Delaney et al. (1981) captured 88 burbot
immediately upstream or downstream from the mouth of tributaries. During 1981, CPUE was
not reported by each period and site. However, the overall monthly CPUE ranged from 0.5
burbot per trotline-day in June to 1.0 burbot per trotline-day in September. Most burbot were
captured near the mouth of Jay Creek (32 fish) and Watana Creek (24 fish) during 1981 (Figure
8.2-15). Sautner and Stratton (1983) sampled at seven locations within the mainstem during
1982 and captured 135 burbot by trotline. Overall monthly CPUE ranged from 0.6 (July and
September) to 0.8 (June) fish per trotline-day. For individual sites and periods, CPUE ranged
from zero (Mainstem Site 2 in September) to 3.5 fish per trotline-day (Watana Creek mouth in
May; Figure 8.2-15). Burbot appeared to move little within the Upper Susitna River, or they
may have returned to feeding territories. Floy tags were attached to 23 and 69 burbot in 1981
and 1982, respectively. Four of the burbot tagged during 1981 and three of burbot tagged during
1982 were recaptured during 1982 at the location of tagging (Sautner and Stratton (1983). Based
upon observation of spent burbot and observations by anglers in Paxson Lake, Delaney et al.
(1981c) suggested that burbot probably spawned during March in the Upper Susitna River.
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8.2.2.4. Round Whitefish
Round whitefish were present in the Upper Susitna River (Delaney et al. 1981b, Sautner and
Stratton 1983). Delaney et al. (1981) captured a total of 80 round whitefish immediately
upstream or downstream of tributary mouths. Gillnets were effective at capturing adult round
whitefish (33 fish), and beach seining and electrofishing captured 47 juvenile round whitefish at
the mouth of Jay Creek. Jay and Kosina creeks accounted for 39.4 and 27.3 percent of the adult
round fish captured. None of the 17 floy-tagged round whitefish were recaptured. During the
studies by Sautner and Stratton (1983), five adult round whitefish were captured at the Watana
Creek Slough during July and August and in prespawning condition.
8.2.2.5. Humpback Whitefish
Humpback whitefish were present in the Upper Susitna River in low numbers. During 1981, one
humpback whitefish (347 mm in length) was captured at the mouth of Kosina Creek (Delaney et
al. 1981), and in 1982, a single humpback whitefish was captured at RM 208.1 (Sautner and
Stratton (1983). Delaney et al. 1981 also reported that humpback whitefish were present in lakes
Susitna and Louise. These lakes are headwater lakes to the Tyrone River, which enters the
Susitna River near RM 246.5.
8.2.2.6. Longnose Sucker
Longnose suckers were present throughout the mainstem Upper Susitna River to at least the
Oshetna River (Delaney et al. 1981b, Sautner and Stratton 1983). Delaney et al. (1981) captured
168 longnose suckers immediately upstream or downstream from the mouth of all surveyed
tributaries except Fog and Tsusena creeks. Gillnets were effective at capturing adult round
whitefish (144 fish). Beach seines, electrofishing, and minnow traps captured 24 juvenile
longnose suckers. The Watana Creek and Jay Creek sites accounted for 52.1 and 19.4 percent of
the adult longnose suckers captured. However, catch rates were highest in Watana Creek (12.5
fish per net-day) and the Oshetna River (4.0 fish per net-day).
During 1982, longnose suckers were captured by gillnets at four of the seven mainstem slough
sites (Sautner and Stratton 1983). Similar to 1981, the highest catch occurred near Watana Creek
(80.3 percent of all captured suckers). The highest catch observed was in July, when 21
longnose suckers were captured near the mouth of Watana Creek. Longnose suckers were in
spawning condition in May and early-June, but all were spent in late-June.
Tags were attached to 97 and 50 longnose suckers in 1981 and 1982, respectively (Sautner and
Stratton 1983). One of the fish tagged in 1981 was recaptured during 1981, and two were
recaptured in 1982. Two fish tagged in 1982 were subsequently recaptured. All recaptures
occurred at the tagging location.
8.2.2.7. Sculpin
In 1981, slimy sculpin were captured in minnow traps within all tributaries sampled in the Upper
Susitna River except Jay Creek (Delaney et al. 1981c). Catch rates were highest in Fog Creek (8
per trap-day), Tsusena Creek (9 per trap-day), and the Oshetna River (10 per trap-day). Length
of captured sculpins ranged from 37 to 95 mm.
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8.2.2.8. Lake Trout
Sampling for lake trout occurred in Sally Lake in 1981 and 1982 and in Deadman Lake in 1981
(Delaney et al. 1981c, Sautner and Stratton 1983). Sally Lake is a 63 acre lake with a maximum
depth of 27 feet and mean depth of 11.6 feet (Figure 8.2-16; Sautner and Stratton 1983). The
southern end of the lake is shallow (average depth of about 4 feet) and has substantial aquatic
vegetation.
In 1981, sampling in Sally Lake was primarily by gillnet with some angling, and only angling
was attempted at Deadman Lake. Lake trout were captured in both Sally Lake (32 fish, 2 by
angling) and Deadman Lake (3 fish, all by angling). Lake trout in Sally Lake were captured in
less than 6 feet of water and within 100 feet of shore. The length of lake trout in Sally Lake
ranged from 305 to 508 mm with a mean of 410 mm. Most scales removed from Lake Trout
were unreadable. Consequently, no age information was obtained. In 1982, sampling in Sally
Lake resulted in the capture of 32 lake trout (Sautner and Stratton 1983), and fish sizes ranged
from 260 to 490 mm with an average length of 419 mm.
8.3. Age and Size of Selected Resident Fish Species
Age and size (length) information was collected from captured resident and non-salmonid
anadromous fish during all of the surveys conducted as part of the RJ component of the Su-
Hydro Aquatic Studies Program. Fish age was determined through analysis of scales or otoliths.
The range of age and size structure of the collected species did not vary substantially from year
to year (Figures 8.3-1 to 8.3-7). However, the mean size at age during some years was affected
by low sample size. Age determination was not possible for Dolly Varden and Arctic lamprey.
Representative length frequency histograms from surveys in 1981 are provided in Figure 8.3-8.
8.4. Invasive Fish Species
The only documented invasive species in the Susitna River basin is northern pike, which were
illegally transplanted into several lakes of the Yentna River in the 1950s (Delaney et al. 1981a).
During the 1980s Aquatic Studies Program five northern pike were captured: one in Kroto
Slough (RM 36.2), one at the Yenta Station fishwheel, and three at the Flathorn Station
fishwheel (RM 22.4). Since the 1980s, the range of northern pike in the Susitna River basin has
expanded greatly, and they are currently present throughout the Lower Susitna River and its
tributaries (Ivey et al. 2009), yet may also be present elsewhere within the basin. Rutz (1996 and
1999) conducted several years of radio-tracking, demographics, and diet studies on northern
pike.
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9. BARRIERS TO MIGRATION
9.1. Tributary Barriers
Using passage criteria based upon Thomson (1972), passage by adult salmon into tributary
streams for spawning was evaluated for fifteen streams in the Lower and Middle Susitna River
(Table 9.1-1; Trihey 1983, Ashton and Trihey 1985). Minimum depth for passage was 0.8 feet
for Chinook salmon and 0.6 feet for coho, chum, pink, and sockeye salmon. Maximum velocity
for passage was 8 feet per second for Chinook, coho, and chum salmon and 7 feet per second for
pink and sockeye salmon. Under existing conditions, Ashton and Trihey (1985) concluded
passage was not restricted at any of the tributary mouths in the Lower Susitna River. However,
there were possible passage problems at Caswell Creek, Goose Creek, Montana Creek, and
Trapper Creek. The types of potential problems were from low tributary flows, debris jams, or
channel changes that could occur regardless of the proposed project. Under mainstem flows of
14,000 to 21,000 cfs at Gold Creek, Trihey (1983) concluded passage was not restricted at Indian
River and Portage Creek, and under the flow regime considered for the proposed 1980s project
configuration, the authors of both studies concluded that, passage into the tributaries would not
be adversely affected by the proposed configuration.
9.2. Access to Sloughs
Sloughs provide important spawning habitat for chum and sockeye salmon, and side channels
were occasionally used by chum and pink salmon. Sautner et al. (1984) evaluated passage into
and within eight slough and four side channel sites. These included Whiskers Creek Slough,
Sloughs 8A, 9, 9A, 11, 20, 21, and 22 and the following side channels: Mainstem 2 Side
Channel, Side Channel 10, Upper Side Channel 11, and Side Channel 21. Most of sites were
selected because of their use as spawning sites for chum salmon. Whiskers Creek Slough was
selected, because it was used by pink salmon for spawning and served as a migration corridor
into Whiskers Creek. Salmon spawning was not known to occur in Side Channel 10; however, it
was selected for study because of its potential as a mitigation site. Chum salmon have been
observed to spawn in Mainstem 2 Side Channel (RM 114.5), but the side channel was not
consistently or heavily used (Sautner et al. 1984).
Sautner et al. (1983) reported that three types of flow (i.e., breaching, backwater, and local) were
important for passage into sloughs and for accessing available spawning habitat within the
slough. When mainstem discharge exceeded the breaching flow for a slough, passage was
unrestricted. However, when mainstem discharge was less than the breaching flow, passage was
a function of the mainstem backwater conditions at the mouth of the slough and of the amount of
local flow present from groundwater and/or tributaries.
Slough morphology may also be an important physical constraint. Slough bathymetry is seldom
regular. A slough may have shallow areas at the mouth and also at various locations within the
slough. As an example, a plan view with spawning areas and a thalweg profile for Slough 9 is
provided in Figure 9.2-1 and Figure 9.2-2. Sautner et al. (1983) identified five critical passage
reaches. The head of Slough 9 began to breach at 16,000 cfs and was fully breached at 19,000
cfs. These flows were exceeded about 45 percent and 29 percent of the time, respectively,
during the critical spawning period from August 20 to September 20 (Sautner et al. 1983).
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Sautner et al. (1983) reported that most slough heads were fully breached at flows between
19,000 and 42,000 cfs. At lower discharges, mainstem flows that created backwaters controlled
passage at the one or two downstream passage reaches within a slough. The authors concluded
that backwater flows were the most important factor for successful passage into a slough. For
Slough 9, the critical mainstem discharge level that provided successful passage at the mouth of
the slough (Passage Reach I) was less than 12,000 cfs (70 percent exceedance value). For some
sloughs, including Slough 9, stage rating curves were incomplete, and therefore, precise critical
passage flows could not be determined.
If mainstem discharge provides a sufficient backwater flow for passage into a slough, local flows
can be important for allowing passage across reaches within a slough and thus can determine the
overall amount of habitat available for spawning. For Slough 9, it was determined that passage
would be successful at Passage Reach I, II, and III with local flows of 2, 1, and 6 cfs,
respectively. Sautner et al. (1983) concluded that local flows were generally adequate for
passage at interior passage reaches as long as fish were able to successfully pass at the slough
entrance.
Of the eight sloughs evaluated, Slough 9 and Slough 21 had the highest risk of unsuccessful
passage conditions when flows were below the breaching level. Access to spawning areas
upstream of Passage Reach III at Slough 9 would not be successful at flows lower than
breaching, unless local flows were higher than 6 cfs; however, an analysis of local flows
indicated that groundwater and tributary flows provided only approximately 5 cfs under base
flow conditions. At Slough 21, chum salmon were observed to hold downstream of Passage
Reach I and did not enter the slough until the head was breached.
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10. ACCESS ALIGNMENT, CONSTRUCTION AREA, AND
TRANSMISSION ALIGNMENT
Three transmission lines associated with the Project are proposed that will follow one or more
routes (AEA 2011). One proposed transmission corridor, named the Chulitna Corridor, would
extend west from the proposed Watana dam site on the north side of the Susitna River to the
Anchorage-Fairbanks Intertie near the Chulitna River. A second proposed corridor, the Gold
Creek Corridor, would run westward on the south side of the Susitna River and connect to the
intertie at Gold Creek. A third option, the Denali Corridor, would extend north from the
proposed dam site to the Denali Highway and then head west along the Denali Highway to an
interconnection point at Cantwell. The two options being considered for the three transmission
line are: 1) two circuits extending west and one circuit north, or 2) three circuits extending west
(AEA 2011).
Access roads are intended to be co-located with transmission corridors and facilities to the extent
possible. However, there are three specific sections of the proposed corridors that would not be
co-located. For the Chulitna Corridor, the access road would be co-located with the transmission
line with the exception of the eastern-most five miles of transmission line (AEA 2011). The
Gold Creek Corridor will be most efficiently run by spanning the line over the rough terrain
adjacent the Susitna River; consequently, the only co-located section of access road would be the
western portion of the corridor (AEA 2011). The northern Denali Corridor will be co-located
with the access road except for a 9-mile section near Deadman Lake; once at the Denali
Highway, the corridor would follow the highway west to Cantwell. Transmission line sections
without co-located roads in each proposed corridor would be accessed by helicopter (AEA
2011).
Construction will consist of right-of-ways for transmission lines, access roads, switchyards, and
substations. Transmission right-of-ways will consist of linear strips of land 200, 300, or 400 feet
in width depending on the number of lines (1, 2, or 3 lines; AEA 2011). The total area necessary
for switchyards and substations is anticipated to be approximately 16 acres (AEA 2011).
Construction access to all sites will be on planned permanent access roads. Stream crossings
associated with the Chulitna Corridor access would occur at Tsusena Creek, Portage Creek,
Devil Creek, Indian River, and two unnamed streams (AEA 2011). For the Gold Creek Corridor
access, stream crossings would occur at Fog Creek, Prairie Creek, and five unnamed streams
(AEA 2011). An alternative Gold Creek access route would not cross Prairie Creek but would
cross an additional unnamed stream. The Denali Corridor access would require crossings of
Deadman, Brushkana, Seattle, and Shale Creeks (AEA 2011).
10.1. Description of 1980s Alignments Pertinent to the Current
Project
The transmission corridor route selected for the 1980s project extended to the west of the Watana
dam to Gold Creek (Schmidt et al. 1984b). The proposed 1980s access corridors, which
correspond to alternative transmission line corridors for the current project, extended north from
the proposed Watana Dam site to the Denali Highway and west from the dam to Gold Creek.
The proposed northern route followed a similar path as the Denali Corridor, while the west
access route followed a route comparable to a portion of the Chulitna Corridor. During the 1983
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open water season, studies were conducted to identify baseline fishery and stream habitat
information at proposed stream crossings and selected lakes near the proposed transmission and
access corridor routes. Stream crossings studied during 1983 that are pertinent to the current
Project include: Deadman, Brushkana, and Seattle creeks in association with the Denali Corridor;
and Tsusena and Devil creeks associated with the Chulitna Corridor (Schmidt et al. 1984b).
Deadman, Tsusena and Devil creeks are tributaries to the Susitna River, while Brushkana and
Seattle Creeks are located in the Tanana River basin.
10.2. Fish Assemblage
In 1983 species observed at the Denali Corridor stream crossings of interest (i.e., Deadman,
Brushkana, and Seattle creeks) were Arctic grayling, slimy sculpin, and Dolly Varden (Schmidt
et al. 1984b). Arctic grayling and slimy sculpin were found at all three proposed crossings.
Dolly Varden were observed only at the Seattle Creek crossing, yet they were also observed in
unnamed stream elsewhere in the Deadman and Brushkana basins (Schmidt et al. 1984b).
A greater number of species were observed at the stream crossings of interest along the proposed
Chulitna Corridor than those along the proposed Denali Corridor. At the proposed Tsusena
Creek crossing, which was located upstream of a large waterfall, small stream resident Dolly
Varden and slimy sculpin were the only fish captured in 1983 (Schmidt et al. 1984b).
Downstream of the Tsusena Creek falls, which is located approximately 3 miles upstream of the
mouth, Arctic grayling were observed (Schmidt et al. 1984b). At the Devil Creek crossing,
slimy sculpin were the only fish species captured in 1983, though Dolly Varden were observed at
other sites in the Devil Creek basin (Schmidt et al. 1984b). The observed fish assemblage in
Portage Creek included Chinook, chum, coho and pink salmon, and rainbow trout, Arctic
grayling, and Dolly Varden (Jennings et al. 1984, Sundet and Pechek 1985).
10.3. Aquatic Habitat
Deadman Creek is a large clearwater tributary to the Susitna River. Deadman Lake is located
approximately 19 miles upstream of the creek’s confluence with the Susitna River. The
proposed access crossing was located about 15 miles upstream of Deadman Lake. The crossing
site was in a steep, narrow, confined section of Deadman Creek with large substrates (cobble and
boulder) and limited fish rearing habitat. Immediately downstream of the crossing site, the
stream channel was less steep and better suited for fish holding and rearing (Schmidt et al.
1984b). Measured discharge at the crossing site in August 1983 was 37 cfs (Schmidt et al.
1984b).
Brushkana Creek is a large, low gradient tributary to the Nenana River and is approximately 26
miles long. The historic crossing site was located approximately 10 miles downstream of the
headwaters in a broad valley (45-50 feet wide), with cobble and boulder substrate and pool-riffle
channel morphology. Qualitative assessments of stream habitat conditions at the crossing site
suggested high quality fish holding and rearing habitat (Schmidt et al. 1984b). Measured
discharge at the crossing site in August 1983 was 83 cfs (Schmidt et al. 1984b).
Seattle Creek is a large clearwater tributary to the Nenana River approximately 12 miles in
length. The historic crossing site was approximately 6 miles upstream of the confluence with the
Nenana River. At the crossing site, the stream channel was approximately 25-30 feet wide with
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boulder, cobble and gravel substrate and pool-riffle channel morphology (Schmidt et al. 1984b).
Measured discharge at the crossing site in August 1983 was 31 cfs (Schmidt et al. 1984b).
Tsusena Creek is a large clearwater tributary to the Susitna River, is approximately 30 miles in
length, and has a large waterfall three miles upstream of the Susitna River. Tsusena Creek drains
a large area of tundra downstream of the headwater area. The historic crossing site, located
approximately 8 miles upstream of the confluence with the Susitna River, was situated in a wide
section (150-200 feet wide) of the creek that consisted primarily of long riffles with small pools.
Cobble and boulder substrates were highly embedded with sand, and gravel was found only in
pools. In 1983, fish rearing and holding habitat appeared to be of high quality (Schmidt et al.
1984b).
Devil Creek, which is a large clearwater tributary to the Susitna River, originates in the Alaska
Range and flows through a wide expanse of open tundra for much of its length. A steep cascade
and waterfall, which blocked upstream fish access, was located approximately one mile upstream
of the Susitna River confluence. The historic crossing site, located approximately seven miles
upstream of the Susitna River confluence, was located in a wide and deep section of the river
with moderate gradient and boulder and cobble substrate (Schmidt et al. 1984b).
10.4. Water Quality
In August 1983, instantaneous water quality measurements were recorded at stream crossing
sites as part of the access and transmission corridor studies. Surface water temperatures in
streams that are pertinent to the current proposed transmission and access corridors ranged from
6.6°C in Seattle Creek to 7.4°C in Deadman Creek (Schmidt et al. 1984b). Dissolved oxygen
concentrations ranged from 9.1 mg/L in Devil Creek to 10.4 mg/L in Deadman Creek (Schmidt
et al. 1984b). Conductivity ranged from 33 µmhos/cm in Deadman Creek to 67 µmhos/cm in
Tsusena Creek (Schmidt et al. 1984b). Measurements of pH ranged from 6.6 in Deadman Creek
to 7.2 in Brushkana Creek (Schmidt et al. 1984b).
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11. AQUATIC PRODUCTIVITY
The production of freshwater fishes in a given habitat is constrained both by the suitability of the
abiotic environment and by the availability of food resources (Wipfli and Baxter 2010). Algae is
responsible for the majority of photosynthesis in a river or stream and serves as an important
food source to many benthic macroinvertebrates. As such it is an important base component in
the lotic food web. In turn, benthic macroinvertebrates are an essential component in the
processes of an aquatic ecosystem, due to their position as consumers at the intermediate trophic
level of lotic food webs (Hynes 1970; Wallace and Webster 1996; Hershey and Lamberti 2001).
Macroinvertebrates are involved in the recycling of nutrients and the decomposition of terrestrial
organic materials in the aquatic environment and thus serves as a conduit for the energy flow
from organic matter resources to vertebrate populations, namely fish (Hershey and Lamberti
2001; Hauer and Resh 1996; Reice and Wohlenberg 1993; Klemm et al. 1990). Aquatic insects
are generally considered the primary food source for juvenile anadromous salmon and other
resident fishes (Wipfli and Baxter 2010). Aquatic insect larvae, pupae, and nymphs can live
within the interstitial spaces in the substrate, on the substrate surface, or be found in the water
column. Other likely important forage items are fish eggs, terrestrial insects, fish tissue from
carcasses, and whole fish. In turn, nutrients and energy provided by spawning salmon have the
potential to increase freshwater and terrestrial ecosystem productivity (Wipfli et al. 1998;
Cederholm et al. 1999; Chaloner and Wipfli 2002; Bilby et al. 2003; Hicks et al. 2005) and may
subsidize otherwise nutrient-poor ecosystems (Cederholm et al. 1999).
The significant functional roles that macroinvertebrates and algae play in food webs and energy
flow in the freshwater ecosystem make these communities important elements in the study of a
stream’s ecology. Studies during the 1970s and 1980s included evaluations of the benthic
macroinvertebrate community, primary productivity, and dissolved nutrients. (Friese 1975; Riis
1975, Riis 1977, Estes et al. 1981, ADF&G 1983, Hansen and Richards 1985, Trihey and
Associates 1986, Van Niuwenhuyse 1985).
11.1. Benthic Macroinvertebrates
A number of evaluations of the benthic macroinvertebrate community were conducted on the
Susitna River in the 1970s and in the 1980s for the original APA Susitna Hydroelectric Project
(Friese 1975; Riis 1975, 1977; ADF&G 1983; Hansen and Richards 1985, Van Nieuwenhuyse
1985, Trihey and Associates 1986). ADF&G studies in the 1970s included sampling of
macroinvertebrates using artificial substrates (rock baskets) deployed for a set period of time to
allow for colonization. Friese (1975) and Riis (1975) set a total of eight rock baskets in
Waterfall Creek, Indian River, and the mainstem middle Susitna River for 30 days during the
summer (July – September). Riis (1977) also deployed rock baskets in the Susitna River near the
mouth of Gold Creek for a colonization period of 75 days; however, only two of seven baskets
were retrieved. Results were limited to low numbers of invertebrates per basket, identified to
taxonomic family.
Studies conducted in the 1980s for the original APA Susitna Hydroelectric Project focused on
benthic macroinvertebrate communities in the sloughs, side channels, and tributaries of the
middle reach of the Susitna River (RM 125 to 142) during the period from May through October.
Efforts included direct benthic sampling with a Hess bottom sampler and drift sampling.
ADF&G efforts in 1982 and 1984 also involved collection of juvenile salmon in these side
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channels and sloughs, and an analysis was conducted to compare gut contents with the drift and
benthic sampling results (ADF&G 1983; Hansen and Richards 1985). In addition, Hansen and
Richards (1985) collected water velocity, depth, and substrate-type data to develop habitat
suitability criteria (HSC), which were used to estimate weighted usable areas for different
invertebrate community guilds, based on their behavioral type (swimmers, burrowers, clingers,
and sprawlers) in slough and side channel habitats. Efforts in 1985 (Trihey and Associates 1986)
expanded to include sampling at nine sites in the middle reach of the Susitna River: three side
channels, two sloughs, two tributaries, and two mainstem sites.
Schmidt et al. (1983) collected invertebrates from kick net and drift net sampling. The results
were reported as part of electivity index analyses, but not otherwise summarized in the report.
Proportions of the drift and kick samples from each date and site reported in tables were lumped
differently depending upon the salmon species diet of interest; consequently, quantitative
conclusions are difficult to make without a re-analysis of the data. Nevertheless, a qualitative
review of the tabular data suggests that chironomid larvae, pupae, and adults were the
predominate items collected, often in combination representing well over 50 percent of the items,
but the relative proportions varied considerably among the collections. Some exceptions were
noted. For example at Slough 11 on September 5, 1982, capniid stonefly nymphs represented 90
percent of the invertebrates collected.
Hansen and Richards (1985) concluded the composition of invertebrates within drift samples was
affected by hydraulic conditions at the head of the side slough or side channel. When mainstem
discharge was sufficiently high to breach slide slough channel heads, the amount of drift was
higher than under unbreached conditions. The authors suggested that mainstem discharge
slightly above the critical breaching flow was more important than higher flow levels because
mainstem waters would provide greater amounts of drift, but turbidity would not be too high to
substantially reduce visibility.
The invertebrate community in drift and benthic samples collected during 1984 were relatively
diverse with 14 aquatic or semi-aquatic orders represented as well as eleven non-insect or non-
aquatic orders (Hansen and Richards 1985). Chironomids (dipteran flies) were common
throughout the sampling period and were numerically dominant in both drift and benthic
collections. Ephemeropterans (mayflies) and plecopterans (stoneflies) were the second- and
third-most prominent taxa in drift samples. Ephemeropterans were common in benthic samples
early in the summer, and plecopeterans were more common later in the summer.
Hansen and Richards (1985) developed depth, velocity, and substrate habitat suitability indices
for benthic invertebrate guilds and used instream flow hydraulic models developed for fish
species to develop Weighted Useable Area (WUA) versus flow relationships for the guilds.
Depth was not limiting to any of the guilds. Velocities from 0 to 3.0 feet per second (fps) were
considered optimal for sprawlers, low velocities were optimal for burrowers, and relatively high
velocities (up to 2.2 fps) were considered optimal for swimmers and clingers (Figure 11.1-1).
Burrowers were more commonly found in sand and silt substrate, sprawlers and swimmers were
commonly found in small gravel to rubble-sized substrate, and rubble substrate was optimal for
clingers (Figure 11.1-2).
WUA versus flow relationships were developed for each of the guilds at four sites: Slough 9,
Side Channel 10, Upper Side Channel 11 and Upper Side Channel 21 (Hansen and Richards
1985). In general, WUA increased with increasing flows (e.g., Slough 9; Figure 11.1-3).
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Hansen and Richards (1985) concluded that WUA increases rapidly above the critical breaching
flow level, which is the point where mainstem discharge becomes the main controlling factor.
Baseline field data for benthic primary and secondary production was collected in 1985 as part of
the Primary Production Monitoring Effort (Van Nieuwenhuyse 1985). Chlorophyll-a (chl-a) and
macroinvertebrates were collected from early April to late October in a variety of off-channel
and mainstem habitat sites. Early April sampling took place in an open-water lead in Slough 8A
and revealed high macroinvertebrate densities (average 17,600 individuals/m2) comprised almost
entirely of chironomid larvae. Chlorophyll-a densities averaged 34.4 mg/m2. Macroinvertebrate
densities in Slough 8A averaged 2,950 individuals/m2 in early April (mostly chironomids) and
ranged from 393 to 8,820 individuals/m2 in May 1985, but with considerably more diversity.
During May, chironomids accounted for an average of 53 percent of the density and only 8
percent of the macroinvertebrate biomass. No sampling results were given for summer
macroinvertebrate sampling (June and July). August and September sampling results showed
low average densities at mainstem sites (44 – 164 individuals/m2), yet large increases were
observed in October (1,729 – 7,109 individuals/m2). Average densities in Slough 8A in August
remained similar to spring levels at 2,851 individuals/m2 and surged in September to 13,964
individuals/m2; again, chironomids represented over 80 percent of the density.
11.2. Periphyton
Algal communities were periodically sampled and analyzed for chlorophyll-a at Susitna Station
from 1978 to 1980. In the 1980s, algae samples were collected as part of the APA Project water
quality studies, with sampling conducted at Denali, Cantwell (Vee Canyon), Gold Creek,
Sunshine, and Susitna stations on the Susitna River, as well as on the Chulitna and Talkeetna
rivers (Harza-Ebasco 1985 as cited in AEA 2011a). Analysis showed low productivity (less than
1.25 mg/m3 chlorophyll-a) and indicated algal abundance was most likely limited by high
concentrations of turbidity (AEA 2011a).
In 1985, chlorophyll-a and macroinvertebrates were collected from early April to late October in
a variety of off-channel and mainstem habitat sites as part of the Primary Production Monitoring
Effort (Van Nieuwenhuyse 1985). Early April sampling took place in an open-water lead in
Slough 8A. Chlorophyll-a densities averaged 34.4 mg/m2 during early April and 37 mg/m2
during early May. Algae samples beyond May 1985 were not analyzed; therefore, no data were
available for summer or fall.
11.3. Water Quality and Chemical Constituents
Water quality metrics and chemical constituents were monitored by the USGS and R&M
Consultants at seven stations along the Susitna River and its tributaries: Denali (RM 290.8), Vee
Canyon (RM 223.1), Gold Creek (RM 136.6), Chulitna (RM 98.0), Talkeetna (RM 97.0),
Sunshine (RM 83.9), and Susitna (RM 25.8) stations. The Chulitna and Talkeetna stations
samples were collected from the tributary rivers and not the mainstem Susitna River. During
June, July, and September of 1981, the USGS also collected water quality samples once per
month from five sloughs: 8A, 9, 16B, 19, and 21 (Estes et al. 1981).
Harza-Ebasco (1985) summarized information on two nutrients: nitrogen, and phosphorus. They
also summarized water temperature and turbidity information, which are important factors
affecting primary productivity. Harza-Ebasco (1985) suggested that orthophosphate levels were
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a better indicator of biologically available phosphorus, because other components tend to be
bound with inorganic particulates. Orthophosphate levels were considered to be relatively low at
0.1 mg/L or less throughout the basin (Figure 11.3-1). Nitrogen levels in the form of nitrate were
reported to be at low to moderate levels of less than 0.9 mg/L. Orthophosphate levels measured
at five sloughs during 1981 averaged 0.37 mg/L and ranged from less than 0.03 mg/L (Sloughs
9, 16B, 19, and 21 during June) to 1.5 mg/L (Slough 9 during July; Estes et al. 1981). Nitrate
levels averaged 5.36 mg/L and ranged from 2.9 mg/L (Slough 21 during July and Slough 16B
during September) to 10. 0 mg/L (Slough 19 during June),
Turbidity, as measured in nephelometric turbidity units (NTUs), is a metric of light penetration
which is an important factor affecting primary productivity. Turbidity in the Susitna River was
primarily determined by levels of inorganic glacial flour suspended in the water (Harza-Ebasco
1985). Turbidity levels in the mainstem Susitna River can be quite high (Harza-Ebasco 1985).
Glacial water from the Chulitna River, with turbidity measured as high as 1,920 NTU, is a major
contributor of turbidity to the mainstem Susitna River. The maximum turbidity level measured
in the Talkeetna River during 1982 was 272 NTU. Turbidity is affected by the amount of glacial
melt and precipitation in the form of rain. Consequently, turbidity tends to be high in the
summer and low in the winter (Harza-Ebasco 1985; Figure 11.3-2. Turbidity levels tended to
decline in a downstream direction below the Three Rivers Confluence. Maximum turbidity
measurements at Sunshine and Susitna stations were of 1,056 and 790 NTU, respectively.
Turbidity in side channels and side sloughs was affected by inflows from clear water tributaries
and groundwater (Harza-Ebasco 1985). In addition, breaching at the heads of side sloughs or
side channels allowed turbid mainstem water to flow through. When flows were below
breaching levels, turbidity was substantially lower and less variable (Figure 11.3-3).
Water temperature influences the metabolic rates of fauna critical to nutrient cycling and
production at secondary and higher trophic levels (Allan 1995). Water temperature can also
influence primary production through via photosynthesis and respiratory rates (Russell-Hunter
1970). Morin et al. (1999) conducted a meta-analysis of published primary production and
chlorophyll-a data and found that water temperature had a relatively high influence on
periphyton productivity compared to lake and ocean phytoplankton productivity.
Water temperature was measured along with other physiochemical parameters at the seven
stations described above. Surface and intragravel water temperatures were also measured as part
of studies investigating chum and sockeye salmon egg incubation and winter rearing habitat.
Water temperatures generally began to warm in May and then declined in late August and
September, with maximum temperatures occurring between mid-June and early August and
winter time temperatures just above 0°C (Harza-Ebasco 1985; Figure 11.3-4). Maximum
temperatures throughout the river seldom exceeded 14°C (Figure 11.3-5), although a high of
16.5°C was recorded at Susitna Station on July 9, 1976. Typical of most rivers, water
temperatures in the Susitna River increased in a downstream direction during the open water
period (Figure 11.3-5). The temperature gradient was steeper above Vee Canyon (RM 223.1)
due to the proximity of glaciers providing source water. The moderating influence of
groundwater in side channels and side sloughs during the winter is discussed in Section 6 (Egg
Incubation).
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Quane, T., P. Morrow, and I. Querel. 1985. Hydrological Investigations at Selected Lower
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for Alaska Power Authority. 533 pp.
Quinn, T.P. 2005. The Behavior and Ecology of Pacific Salmon and Trout. University of
Washington Press, Seattle, WA. 378 pp.
R&M (R&M Consultants). 1981. Attachment D: Susitna River Mile Index Mouth to Susitna
Glacier. Prepared for Acres American Inc., by R&M Consultants, Anchorage, Alaska.
42 pp.
Riis, J.C. 1977. Pre-Authorization Assessment of the Proposed Susitna River Hydroelectric
Projects: Preliminary Investigations of Water Quality and Aquatic Species Composition.
Alaska Department of Fish and Game. 100 pp.
Riis, J.C., and N.V. Friese. 1978. Fisheries and Habitat Investigations of the Susitna River - A
Preliminary Study of Potential Impacts of the Devils Canyon and Watana Hydroelectric
Projects. Alaska Department of Fish and Game, Divisions of Sport and Commercial
Fish, Anchorage, AK. 213 pp.
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 78 February 2013
Roth, K.J., and M.E. Stratton. 1985. The Migration and Growth of Juvenile Salmon in the
Susitna River. Pages 207 In: Schmidt, D.C., S.S. Hale, and D.L. Crawford. (eds.)
Resident and Juvenile Anadromous Fish Investigations (May - October 1984). Prepared
by Alaska Department of Fish and Game. Prepared for Alaska Power Authority,
Anchorage, AK.
Roth, K.J., D.C. Gray, J.W. Anderson, A.C. Blaney, and J P. McDonell. 1986. The Migration
and Growth of Juvenile Salmon in the Susitna River, 1985. Prepared by Alaska
Department of Fish and Game, Susitna Hydro Aquatics Studies. Prepared for Alaska
Power Authority Anchorage, Alaska. 130 pp.
Rutz, D.S. 1996. Seasonal movements, age and size statistics, and food habits of northern pike
in Upper Cook Inlet during 1994 and 1995. ADF&G. Anchorage, Alaska.
Rutz, D.S. 1999. Movements, food availability and stomach contents of Northern Pike in
selected Susitna River drainages, 1996-1997. Alaska Department of Fish and Game
Fishery Data Series No. 99-5. Anchorage, Alaska. 78 pp.
Sandone, G., D.S. Vincent-Lang, and A. Hoffman. 1984. Evaluations of Chum Salmon
Spawning Habitat in Selected Tributary Mouth Habitats of the Middle Susitna River.
Pages 83 In: Estes, C.C., and D.S. Vincent-Lang. (eds.) Aquatic Habitat and Instream
Flow Investigations (May - October 1983). Alaska Department of Fish and Game,
Susitna Hydro Aquatic Studies, Anchorage, Alaska.
Sautner, J., and M. Stratton. 1983. Upper Susitna River Impoundment Studies 1982. Alaska
Department of Fish and Game. Anchorage, Alaska. 220 pp.
Sautner, J.S., L.J. Vining, and L.A. Rundquist. 1984. An evaluation of passage conditions for
adult salmon in sloughs and side channels of the middle Susitna River. Pages 148 In:
Estes, C.C., and D.S. Vincent-Lang. (eds.) Aquatic Habitat and Instream Flow
Investigations (May - October 1983). Alaska Dept. Fish and Game. Susitna Hydro
Aquatic Studies, Anchorage, Alaska.
Schmidt, D., and A. Bingham. 1983. Synopsis of the 1982 Aquatic Studies and Analysis of Fish
and Habitat Relationships. Alaska Department of Fish and Game, Susitna Hydro Aquatic
Studies, Anchorage, Alaska. 185 pp.
Schmidt, D., S. Hale, D. Crawford, and P. Suchanek. 1983. Resident and Juvenile Anadromous
Fish Studies on the Susitna River Below Devil Canyon, 1982. Prepared by Alaska
Department of Fish and Game for the Alaska Power Authority. 303 pp.
Schmidt, D.C., S.S. Hale, D.L. Crawford, and P.M. Suchanek. 1984a. Resident and juvenile
anadromous fish investigations (May - October 1983). Prepared for the Alaska Power
Authority. Alaska Department of Fish and Game Susitna Hydro Aquatic Studies
Anchorage, Alaska. 458 pp.
Schmidt, D.C., C.C. Estes, D.L. Crawford, and D.S. Vincent-Lang. 1984b. Access and
Transmission Corridor Aquatic Investigations (July - October 1983). Prepared by Alaska
Department of Fish and Game. Prepared for Alaska Power Authority, Anchorage, AK.
140 pp.
Seagren, D.R., and R.G. Wilkey. 1985. Summary of water temperature and substrate data from
selected salmon spawning and groundwater upwelling sites in the middle Susitna River.
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 79 February 2013
ADF&G Susitna River Aquatic Studies Program Technical Data Report No 12. Prepared
for Alaska Power Authority, Anchorage, Alaska. 90 pp.
Seagren, D.R., and R.G. Wilkey. 1985. Preliminary Evaluations of Potential Fish Mitigation
Sites in the Middle Susitna River. Report to Alaska Power Authority by Alaska
Department of Fish and Game, Susitna Hydro Aquatic Studies, Anchorage, Alaska. 268
pp.
Shields, P., and A. Dupuis. 2012. Upper Cook Inlet Commercial Fisheries Annual Management
Report, 2011. Fishery Management Report No. 12-25. Alaska Department of Fish and
Game, Anchorage, Alaska. 202 pp.
Steward, C.R., R.C. Wilkinson, and A.M. Milner. 1985. Response of Juvenile Chinook Habitat
to Mainstem Discharge in the Talkeetna-to-Devil Canyon Segment of the Susitna River,
Alaska. Final Report to Alaska Power Authority by Trihey and Associates, Anchorage,
Alaska. 183 pp.
Stratton, M.E. 1986. Summary of Juvenile Chinook and Coho Salmon Winter Studies in the
Middle Susitna River, 1984-1985. Report to Alaska Power Authority by Alaska
Department of Fish and Game, Susitna Hydro Aquatic Studies, Anchorage, Alaska. 148
pp.
Suchanek, P.M., K.J. Kuntz, and J.P. McDonell. 1985. The Relative Abundance, Distribution,
and Instream Flow Relationships of Juvenile Salmon in the Lower Susitna River. Pages
208 - 483 In: Schmidt, D.C., S.S. Hale, and D.L. Crawford. (eds.) Resident and Juvenile
Anadromous Fish Investigations (May - October 1984). Prepared by Alaska Department
of Fish and Game for the Alaska Power Authority.
Suchanek, P.M., R.P. Marshall, S.S. Hale, and D.C. Schmidt. 1984. Juvenile Salmon Rearing
Suitability Criteria. Pages 57 In: Schmidt, D., S.S. Hale, D.L. Crawford, and P.M.
Suchanek. (eds.) Part 3 of Resident and Juvenile Anadromous Fish Investigations (May -
October 1983). Prepared by Alaska Department of Fish and Game. Prepared for Alaska
Power Authority, Anchorage, AK.
Sundet, R.L. 1986. Winter Resident Fish Distribution and Habitat Studies Conducted in the
Susitna River Below Devil Canyon, 1984-1985. Report to Alaska Power Authority by
Alaska Department of Fish and Game, Susitna Hydro Aquatic Studies, Anchorage,
Alaska. 80 pp.
Sundet, R.L., and S.D. Pechek. 1985. Resident Fish Distribution and Life History in the Susitna
River Below Devil Canyon. Pages 97 In: Schmidt, D.C., S.S. Hale, and D.L. Crawford.
(eds.) Resident and Juvenile Anadromous Fish Investigations (May - October 1984).
Prepared by Alaska Department of Fish and Game. Prepared for Alaska Power
Authority, Anchorage, AK.
Thompson, F. M., S. Wick, and B. Stratton. 1986. Adult Salmon Investigations: May - October
1985. Report to Alaska Power Authority by Alaska Department of Fish and Game,
Susitna Hydro Aquatic Studies, Anchorage, Alaska. 173 pp.
Trihey, E.W. 1982. Preliminary Assessment of Access by Spawning Salmon to Side Slough
Habitat Above Talkeetna. Prepared for Acres American Incorporated. 29 pp.
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Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 80 February 2013
Trihey, E.W. 1982. 1982 Winter Temperature Study. Prepared for Acres American, Inc. by
E.W. Trihey, Anchorage, Alaska. 151 pp.
Trihey, E.W. 1983. Preliminary Assessment of Access by Spawning Salmon into Portage Creek
and Indian River. Prepared for Alaska Power Authority, Anchorage, AK. 1983 pp.
Trihey & Associates and Entrix. 1985. Instream Flow Relationships Report. Final Report to
Alaska Power Authority, Anchorage, Alaska. 228 pp.
Trihey, E.W., and N.D. Hilliard. 1986. Response of Chum Salmon Spawning Habitat to
Discharge in the Talkeetna-to-Devil Canyon Segment of the Susitna River, Alaska. Final
Report to Alaska Power Authority by Trihey and Associates, Anchorage, Alaska. 142
pp.
Thompson, K. 1972. Determining Stream Flows for Fish Life. Pacific Northwest River Basins
Commission Instream Flow Requirement Workshop. March 15-16, 1972. 34 pp.
Vincent-Lang, D., and I. Queral. 1984. Eulachon spawning habitat in the lower Susitna River.
Pages 77 In: Estes, C.C., and D.S. Vincent-Lang. (eds.) Aquatic habitat and instream
flow investigations (May - October 1983). Alaska Department of Fish and Game,
Susitna Hydro Aquatic Studies, Anchorage, Alaska.
Vincent-Lang, D., A. Hoffman, A.E. Bingham, C.C. Estes, D. Hilliard, C. Stewart, E.W. Trihey,
and S. Crumley. 1984. An Evaluation of Chum and Sockeye Salmon Spawning Habitat
in Sloughs and Side Channels to the Middle Susitna River. Pages 339 In: Estes, C.C.,
and D. Vincent-Lang. (eds.) Chapter 7 in Aquatic Habitat and Instream Flow
Investigation (May - October 1983). Alaska Department of Fish and Game, Susitna
Hydro Aquatic Studies, Anchorage, Alaska.
Vincent-Lang, D.S., A. Hoffman, A. Bingham, and C.C. Estes. 1984. Habitat Suitability
Criteria for Chinook, Coho, and Pink Salmon Spawning in Tributaries of the Middle
Susitna River. Pages 79 In: Estes, C.C., and D.S. Vincent-Lang. (eds.) Chapter 9 In
Aquatic and Instream Flow Studies. Alaska Department of Fish and Game, Susitna
Hydro Aquatic Studies, Anchorage, Alaska.
Vining, L.J., J.S. Blakely, and G.M Freeman. 1985. Winter aquatic investigations (September
1983 to May 1984). Alaska Department of Fish and Game, Susitna Hydro Aquatic
Studies; Anchorage, Alaska. 232 pp.
Wangaard, D.B., and C.V. Burger. 1983. Effects of Various Water Temperature Regimes on the
Egg and Alevin Incubation of Susitna River Chum and Sockeye Salmon. U.S. Fish and
Wildlife Service, National Fishery Research Center, Anchorage Alaska. 45 pp.
Westerman, D. L., and T. M. Willette. 2011. Upper Cook Inlet salmon escapement studies,
2009. Fishery Data Series No. 11-33. Alaska Department of Fish and Game, Divisions of
Sport Fish and Commercial Fisheries.
Willette, T. M., R. DeCino, and N. Gove. 2003. Mark-recapture population estimates of coho,
pink, and chum salmon runs to upper Cook Inlet in 2002. Regional Information Report
No. 2A03-20. Alaska Department of Fish and Game, Divisions of Sport Fish and
Commercial Fisheries.
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
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FERC Project No. 14241 Page 81 February 2013
Wilson, W.J. 1985. Summary of Preliminary Results; Task 31 Primary Production Monitoring
Effort. Prepared by Arctic Environmental Information and Data Center. Prepared for
Harza-Ebasco Joint Venture. 22 pp.
Wilson, W.J., C.G. Prewitt, M.D. Kelly, and J.C. LaBelle. 1984. Susitna Hydroelectric Project
Aquatic Impact Assessment: Effects of Project-Related Changes in Temperature,
Turbidity, and Stream Discharge on Upper Susitna Salmon Resources during June
through September. Alaska Power Authority by Arctic Environmental Information and
Data Center, University of Alaska, Anchorage, Alaska. 139 pp.
Wood, C.C. 1995. Life history variation and population structure in sockeye salmon. Pages
195-216 In: Nielsen, J.L., and D.A. Powers. (eds.) American Fisheries Society
Symposium 17. American Fisheries Society, Bethesda, Maryland.
Woodward-Clyde Consultants. 1984. Interim Mitigation Plan for Chum Spawning Habitat in
Side Sloughs of the Middle Susitna River. Report to Alaska Power Authority by
Woodward-Clyde Consultants. 121 pp.
Yanusz, R., R. Merizon, M. Willette, D. Evans, and T. Spencer. 2011. Inriver abundance and
distribution of spawning Susitna River sockeye salmon Oncorhynchus nerka, 2008.
Fishery Data Series No 11-12. Alaska Dept. of Fish and Game, Anchorage, Alaska. 44
pp.
Yanusz, R., R. Merizon, D. Evans, M. Willette, T. Spencer, and S. Raborn. 2007. In river
abundance and distribution of spawning Susitna River sockeye salmon Oncorhynchus
nerka, 2006. Fishery Data Series No 07-83. Alaska Dept. of Fish and Game, Anchorage,
Alaska. 68 pp.
Yanusz, R.J., R.A. Merizon, T.M. Willette, D.G. Evans, and T.R. Spenser. 2011. Inriver
abundance and distribution of spawning Susitna River sockeye salmon Oncorhynchus
nerka, 2007. Fishery Data Series No. 11-19. Alaska Department of Fish and Game,
Anchorage, Alaska. 50 pp.
Yanusz, R.J. 2013. ADF&G Fish Biologist personal communication with M. Nemeth, LGL
Alaska Research Associates, Inc. ,February 26, 2013.
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13. TABLES
REPORT SYNTHESIS OF EXISTING FISH POPULATION DATA
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Table S-1. Periodicity of adult Pacific salmon presence in the Susitna River. Light gray indicates total duration of residence and dark gray represents periods of peak
use.
Species Life Stage Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Chinook
Salmon
Adult Migration
Spawning
Chum
Salmon
Adult Migration
Spawning
Coho
Salmon
Adult Migration
Spawning
Sockey
e
Salmon1
Adult Migration A A A B
B
Spawning A A B
B
Pink
Salmon
Adult Migration
Spawning
Notes:
1 First-run (A) and second-run (B) sockeye salmon exhibit distinct timing of adult migration and spawning, and utilize separate areas for spawning. Early-run
sockeye do not spawn in the middle Susitna River.
Peak Use Off-Peak Use
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Table 3.1-1. List of documents related to fish and aquatics studies on the Susitna River from the 1970s and 1980s.
Year Title APA Doc ID(s) Type
No of
APA
Docs Citation
1974 An Assessment of the Anadromous Fish Populations in the Upper Susitna River
Watershed between Devil Canyon and Chulitna River
1612 Study 1 Barrett 1974
1975 December, January, and February Investigations on the Upper Susitna River
Watershed Between Devil Canyon And Chulitna River
1609 Study 1 Barrett 1975
1975 Preauthorization Assessment of Anadromous Fish Population Upper Susitna River
Watershed in the Vicinity of Proposed Devil Canyon Hydroelectric Project
549 Study 1 Friese 1975
1977 Pre-authorization Assessment of the Proposed Susitna River Hydroelectric Projects:
Preliminary Investigations of Water Quality and Aquatic Species Composition
1610 Study 1 Riis 1977
1978 Preliminary Environmental Assessment of Hydroelectric Development on the Susitna
River
1613 Summary 1 Riis and Friese 1978
1981 Attachment D to Hydrographic Surveys: Susitna River Mile Index SUS131 Other 1 R&M 1981
1981 Resident Fish Investigation on the Lower Susitna River 318 Study 1 Delaney et al. 1981a
1981 Juvenile Anadromous Fish Study on the Lower Susitna River 1310 Study 1 Delaney et al. 1981b
1981 Resident Fish Investigation on the Upper Susitna River 316 Study 1 Delaney et al. 1981c
1981 Aquatic Habitat and Instream Flow Project 311, 312, 1307 Study 3 Estes et al. 1981
1981 Adult Anadromous Fisheries Project 324 Study 1 ADF&G 1981
1982 Aquatic Studies Procedures Manual 3554, 3555 SOP 2 ADF&G 1982a
1982 Aquatic Studies Program 1982 517 Synthesis 1 Estes and Bingham 1983
1982 Stock Separation Feasibility 320 Study 1 ADF&G 1982b
1982 Adult Anadromous Fish Studies, 1982 588, 589 Study 2 ADF&G 1982c
1982 1982 Winter Temperature Study Open File Report 526 Study 1 Trihey 1982a
1982 Preliminary Assessment of Access by Spawning Salmon to Side Slough Habitat
above Talkeetna
510 Study 1 Trihey 1982b
1983 Resident and Juvenile Anadromous Fish Studies on Susitna, Below Devil Canyon 486, 487 Study 2 Schmidt et al. 1983
1983 Winter Aquatic Studies (October 1982 - May 1983) 397 Study 1 Hoffman et al. 1983
1983 Aquatic Habitat and Instream Flow Studies 1982 585, 586, 587 Study 3 Estes and Schmidt 1983
1983 Upper Susitna River Impoundment Studies 1982 590 Study 1 Sautner and Stratton 1983
1983 Report Synopsis of the 1982 Aquatic Studies and Analysis of Fish and Habitat
Relationships and Appendices
40 Synthesis 1 Schmidt and Bingham 1983
1983 Summarization of Volumes 2, 3, 4; Parts I and II, and 5 96 Synthesis 1 ADF&G 1983
1983 Aquatic Studies Procedures Manual 938 SOP 1 ADF&G 1983
1983 Upper Susitna River Salmon Enhancement Study Final of 522 (draft) Study 1 Barrick et al. 1983
1983 Effects of Various Water Temperature Regimes on the Egg and Alevin Incubation of
Susitna River Chum and Sockeye Salmon
317 Study 1 Wangaard and Burger 1983
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Year Title APA Doc ID(s) Type
No of
APA
Docs Citation
1983 Preliminary Assessment of Access by Spawning Salmon into Portage Creek and
Indian River
508 Study 1 Trihey 1983
1983 Slough Hydrogeology Report 519 Study 1 Burgess 1983
1984 Adult Anadromous Fish Investigations (May -October 1983) 1450 Study 1 ADF&G 1984
1984 Resident and Juvenile Anadromous Fish Investigations (May -October 1983) 1784 Study 1 Schmidt et al. 1984;
Dugan et al. 1984;
Suchanek et al. 1984
1984 Aquatic Habitat and Instream Flow Investigations (May - October 1983) 1930, 1931, 1934,
1935, 1936, 1937,
1938
Study 7 Vincent-Lang and Queral
1984;
Quane et al. 1984;
Sandone et al. 1984;
Sautner et al. 1984;
Vincent-Lang et al. 1984a;
Vincent-Lang et al. 1984b
1984 Access and Transmission Corridor Aquatic Investigations (May - October 1983) 2049 Study 1 Schmidt et al. 1984
1984 Effects of Project-related Changes in Temperature, Turbidity and Stream Discharge
on Upper Susitna Salmon Resources During June - Sept
454 Study 1 Wilson et al. 1984
1984 Assessment of the Effects of the Proposed SHP on Instream Temperature and
Fishery Resources in the Watana to Talkeetna Reach
2330 Study 1 Meyer et al. 1984
1984 Interim Mitigation Plan for Chum Spawning Habitat in Side Sloughs of the Middle
Susitna River
2332 Study 1 Woodward-Clyde
Consultants 1984
1984 Slough Geohydrology Studies 1718 Study 1 Harza-Ebasco and R&M
1984
1984 ADF&G Su Hydro Aquatic Studies (May 1983 - June 1984) Procedures Manual 885, 886 SOP 2 ADF&G 1984
1984 Response of Aquatic Habitat Surface Areas to Mainstem Discharge in the Talkeetna
to Devil Canyon Reach of the Susitna River, Alaska.
1693 Study 1 Klinger and Trihey 1984
1985 Winter Aquatic Studies (October 1983 - May1984) 2658, 2659 Study 2 Vining et al. 1985
1985 Adult Anadromous Fish Investigations (May - October 1984) 2748 Study 1 Barrett et al. 1985
1985 Resident and Juvenile Anadromous Fish Investigations (May -October 1984) 2836, 2837 Study 2 Roth and Stratton 1985;
Suchanek et al. 1985;
Sundet and Pechek 1985
1985 Availability of Invertebrate Food Sources for Rearing Juvenile Chinook Salmon In
Turbid Susitna River Habitats
2846 Study 1 Hansen and Richards 1985
1985 Summary Of Salmon Fishery Data For Selected Middle Susitna River Sites 2749 Study 1 Hoffman 1985
1985 Preliminary Evaluations of Potential Fish Mitigation Sites in the Middle Susitna River 2908 Study 1 Seagren and Wilkey 1985a
1985 Lower Susitna River Preliminary Chum Salmon Spawning Habitat Assessment 3504 Study 1 Bigler and Levesque 1985
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Year Title APA Doc ID(s) Type
No of
APA
Docs Citation
1985 Summary of Water Temperature and Substrate Data from Selected Salmon
Spawning and Groundwater Upwelling Sites in the Middle Susitna River
2913 Study 1 Seagren and Wilkey 1985b
1985 Hydrological Investigations at Selected Lower Susitna River Study Sites 2736 Study 1 Quane et al. 1985
1985 Fish Resources and Habitats in the Middle Susitna River 2744 Synthesis 1 Jennings 1985
1985 Assessment of Access by Spawning Salmon into Tributaries of the Lower Susitna
River
2775 Study 1 Ashton and Trihey 1985
1985 Access Corridor, Construction Zone And Transmission Corridor Fish Impact
Assessment and Mitigation Plan
2921 Study 1 Entrix 1985a
1985 Impoundment Area Fish Impact Assessment and Mitigation Plan 2922 Study 1 Entrix 1985b
1985 Characterization of Aquatic Habitats in the Talkeetna to Devil Canyon Segment of
the Susitna River Alaska
2919 Study 1 Aaserude et al. 1985
1985 Instream Flow Relationships 3060, 3061 Study 2 Trihey and Entrix 1985
1985 Hydraulic Relationships and Model Calibration Procedures at 1984 Study Sites in the
Talkeetna-to-Devil Canyon Segment of the Susitna River, Alaska
2898, 2899 Study 1 Hilliard et al. 1985
1985 Response of Juvenile Chinook Salmon Habitat to Mainstem Discharge in the
Talkeetna to Devil Canyon Segment of the Susitna River, Alaska
2909 Study 1 Steward et al. 1985
1985 Response of Aquatic Habitat Surface Areas to Discharge in the Yentna to Talkeetna
Reach of the Susitna River.
2774 Study 1 Ashton and Klinger-
Kingsley 1985
1985 Salmon Passage Validation Studies 2854 Study 1 Blakely et al. 1985
1985 Response of Aquatic Habitat Surface Areas to Discharge in the Talkeetna to Devil
Canyon Segment of the Susitna River Alaska.
2945 Study 1 Klinger-Kingsley et al. 1985
1985 Susitna Hydroelectric Project License Application Exhibit E 3430, 3431, 3432,
3433, 3435, 3438
Synthesis 6 Harza-Ebasco 1985
1985 Resident and Juvenile Anadromous Studies Procedures Manual 3014 SOP 1 ADF&G 1985
1985 Task 31 Primary Production Monitoring Report 4018 Study 1 Wilson 1985
1986 Winter Studies of Resident and Juvenile Anadromous Fish (October 1984 - May
1985)
3062, 3063 Study 2 Sundet 1986; Stratton 1986
1986 Adult Salmon Investigations (May-October 1985) 3412 Study 1 Thompson et al. 1986
1986 The Migration and Growth of the Juvenile Salmon in the Susitna River, 1985 3413 Study 1 Roth et al. 1986
1986 Susitna River Aquatic Studies Review: Findings And Recommendations 3501 Synthesis 1 Cannon 1986
1986 Response of Chum Salmon Spawning Habitat to Discharge in the Talkeetna to Devil
Canyon Segment of the Susitna River, Alaska
3423 Study 1 Trihey and Hilliard 1986
Total Number of Volumes 89
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Table 3.1-2. Types of studies conducted as part of the Fish and Aquatics Study Program during 1981 to 1986.
Year Adult Anadromous Studies Resident and Juvenile Studies Aquatic Habitat Studies
1981
Mainstem escapement monitoring (gillnet,
electrofishing, fishwheel, and sonar sampling); radio-
tracking, run timing, age and length, sex ratios, aerial
and foot spawning surveys between Cook Inlet and
Devils Canyon plus the Yentna River and selected
tributaries (ADF&G 1981).
Resident fish distribution, abundance, age, length,
sex composition, and floy tagging from Cook Inlet to
Devils Canyon (Delaney et al. 1981a) and upstream
of Devils Canyon (Delaney et al. 1981b);
Juvenile anadromous winter and summer
distribution, abundance, age, and length (Delaney et
al. 1981c).
Measurement of physical parameters including
hydrology (flow), hydraulics (water stage and
velocity), water quality, and morphologic mapping at
selected sites (Estes et al. 1981).
1982
Mainstem escapement monitoring (fishwheels,
sonar) downstream of Devils Canyon, tagging, radio-
tracking, run timing, age composition, fecundity,
aerial and foot spawning surveys, eulachon and
Bering cisco spawning surveys (ADF&G 1982C).
Chum and sockeye egg incubation and intragravel
water monitoring in the Middle River (Hoffman et al.
1983);
Distribution and abundance of resident fish and
juvenile salmon downstream of Devils Canyon,
radio-tracking of resident fish, emergence and
outmigration of juvenile salmon, food habitats of
juvenile salmon (Schmidt et al. (1983);
Distribution and abundance of resident fish upstream
of Devils Canyon, tributary habitat, passage barriers,
and fish distribution/abundance, lake habitat and fish
distribution (Sautner and Stratton 1983).
Characterization of spawning and rearing habitat for
anadromous and resident fish (Estes and Schmidt
1983);
Slough hydrogeology (Burgess 1983);
Side slough access by spawning salmon (Trihey
1982);
1983
Mainstem escapement monitoring (fishwheels,
sonar) downstream of Devils Canyon, tagging, run
timing, age composition, fecundity, aerial and foot
spawning surveys, eulachon and Bering cisco
spawning surveys (Barrett et l. 1984).
Outmigration of juvenile salmon upstream of
Talkeetna, distribution and abundance of juvenile
salmon upstream of Talkeetna (Schmidt et al.
1984a);
Temperature effects on chum and sockeye salmon
egg development (Wangaard and Burger 1983);
Access and transmission corridor aquatic study
(Schmidt et al. 1984b)
Collection of hydrologic and water quality information
and information needed for modeling adult salmon
spawning habitat and access into selected sloughs
used for spawning (Sautner et al. 1984);
Juvenile salmon and resident fish rearing suitability
criteria and habitat modeling (Schmidt et al. 1984a);
Assessment of access into Indian and Portage
creeks by spawning salmon (Trihey 1983).
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Year Adult Anadromous Studies Resident and Juvenile Studies Aquatic Habitat Studies
1984
Mainstem escapement monitoring (fishwheels,
sonar) downstream of Devils Canyon, tagging, run
timing, age composition, aerial and foot spawning
surveys (Barrett et al. 1985).
Migration and growth of juvenile salmon (Roth and
Stratton 1985);
Abundance and distribution of juvenile salmon
(Suchanek et al. 1985);
Abundance, distribution, and radio-tracking of
resident fish in the lower Middle River (Sundet and
Pechek 1985);
Invertebrate food sources for Chinook salmon
juveniles (Hansen and Richards 1985).
Water quality monitoring and chum egg incubation
study in the lower Middle River (Vining et al. 1985);
Intragravel water temperature, substrate
composition, chum spawning habitat, and egg
incubation in the Lower River (Bigler and Levesque
1985)
Collection of hydrologic and water quality information
and information needed for modeling spawning and
rearing flow:habitat relationships (Quane et al. 1985);
Instream flow relationships for juvenile salmon
(Suchanek et al. 1985);
Access of spawning salmon into tributaries
downstream of Talkeetna (Ashton and Trihey 1985);
Chum spawning habitat in the Lower River instream
flow model development (Bigler and Levesque
1985).
1985
Mainstem escapement monitoring (fishwheels)
downstream of Devils Canyon, tagging, run timing,
age composition, aerial and foot spawning surveys
(Thompson et al. 1986);
Summary of fishery data (Hoffman 1985).
Winter distribution of burbot and rainbow trout
(Sundet 1986);
Winter distribution, abundance, movement, and
length of juvenile Chinook and coho salmon (Stratton
1986);
Migration and growth of juvenile salmon (Roth et al.
1986).
Preliminary results of primary productivity and
macroinvertebrate monitoring in the Susitna and
Kasilof rivers (Wilson 1985),
Characterization of aquatic habitats in the lower
Middle River (Aaserude et al. 1985);
Juvenile Chinook salmon instream flow modeling
(Steward et al. 1985);
Response of water surface area to discharge in the
Yentna to Talkeetna Reach (Ashton and Klinger-
Kingsley 1985) and Talkeetna to Devils Canyon
Reach (Klinger Kingsley et al. 1985).
1986 No field, laboratory, or desktop studies. No field, laboratory, or desktop studies. Chum salmon spawning instream flow modeling
(Trihey and Hilliard 1986).
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Table 3.1-3. Deployment of fishwheel (F) and sonar stations (S) from 1981 to 1985. Sources: ADF&G 1982a,ADF&G 1982c, Barrett 1984, Barrett 1985, Thompson et al.
1986.
Station
River
Mile
1981 1982 1983 1984 1985
Gear
Period of
Operation Gear
Period of
Operation Gear
Period of
Operation Gear
Period of
Operation Gear
Period of
Operation
Flathorn Station 22 4F 6/29 to 9/3 4F - 6F 5/26 to 9/3
Susitna Station 26.7 2F, 2S 6/27 to 9/2 2F, 2S 7/1 to 9/5
Yentna Station 28, TRM
04
2F, 2S 6/29 to 9/7 2F, 2S 6/27 to 9/5 2F, 2S 6/30 to 9/5 2F, 2S 7/1 to 9/5
Sunshine
Station
80 4F, 2S 6/23 to 9/15 4F, 2S 6/4 to10/1 4F 6/3 to 9/11 4F 6/4 to 9/10 4F 6/3 to 9/10
Talkeetna
Station
103 4F, 2S 6/22 to 9/15 4F, 2S 6/5 to 9/14 4F 6/7 to 9/12 4F 6/3 to 9/11
Curry Station 120 2F 6/15 to 9/21 2F 6/9 to 9/18 2F 6/9 to 9/14 2F 6/9 to 9/14 2F 6/10 to 9/12
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Table 3.1-4. Designated Fish Habitat Sites surveyed June through September 1982. Source: Estes and Schmidt (1983).
Reach Site River Mile
Lower River
GOOSE CREEK 2 AND SIDE CHANNEL 73.1
WHITEFISH SLOUGH 78.7
RABIDEUX CREEK AND SLOUGH 83.1
SUNSHINE CREEK AND SIDE CHANNEL 85.7
BIRCH CREEK AND SLOUGH 88.4
Middle River
WHISKERS CREEK AND SLOUGH 101.2
SLOUGH 6A 112.3
LANE CREEK AND SLOUGH 8 113.6
SLOUGH 8A 125.3
SLOUGH 9 129.2
4th OF JULY CREEK-MOUTH 131.1
SLOUGH 11 135.3
INDIAN RIVER—MOUTH 138.6
SLOUGH 19 140.0
SLOUGH 20 140.1
SLOUGH 21 142.0
PORTAGE CREEK-MOUTH 148.8
Table 3.1-5. Description of habitat zones sampled at Designated Fish Habitat Sites: June through September 1982 (From
Estes and Schmidt 1983).
Zone Code Description
1 Areas with a tributary or ground water source which are not influenced by mainstem stage and which usually
have a significant1 surface water velocity.
2 Areas with a tributary or ground water source which have no appreciable1 surface water velocity as a result of a
hydraulic barrier created at the mouth of a tributary or slough by mainstem stage.
3 Areas of significant surface water velocities, primarily influenced by the mainstem, where tributary or slough
water mixes with the mainstem water.
4 Areas of significant water surface velocities which are located in a slough or side channel above a tributary
confluence (or in a slough where no tributary is present) when the slough head is open.
5 Areas of significant water surface velocities which are located in at slough or side channel below a tributary
confluence when the slough head is open.
6
Backwater areas with no appreciable surface water velocities which result from a hydraulic barrier created by
mainstem stage which occur in a slough or side channel above a tributary confluence (or in a slough or side
channel where no tributary is present), when the head of the slough is open.
7
Backwater areas with no appreciable surface water velocities which result from a hydraulic barrier created by
mainstem stage which occur in a slough or side channel below a tributary confluence, when the head of the
slough is open.
8 Backwater areas consisting of mainstem eddies.
9 A pool with no appreciable surface water surface velocities which is created by a geomorphological feature of a
free-flowing zone or from a hydraulic barrier created by a tributary; not created as a result of mainstem stage.
Notes:
1 “Significant” and “appreciable” surface water velocities mean a velocity of at least 0.5 ft/sec. However, there
are site-specific exceptions to this, based on local morphology.
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Table 3.1-6. Aggregate Hydraulic (H), Water Source (W) and Velocity (V) zones. Source: Estes and Schmidt (1983),
Schmidt et al. (1983).
Aggregate Zone Habitat Zone Included Definition
H-I 1, 4, 5, 9 not backed up by mainstem
H-II 2, 6, 7, 8 backed up by mainstem
H-III 3 mainstem
W-I 1, 2 tributary water and/or ground water only
W-II 4, 6, 8, sometimes 3 mainstem water only
W-III 5, 7, sometimes 3 mixed water sources
V-I1 1, 3, 4, 5 Fast water
V-II1 2, 6, 7, 8, 9 Slow water
Notes:
1 The habitat zones included in aggregate zones V-I and V-II were not provided in the source documents. Zone
descriptions were used to classify which zones were fast and slow water.
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Table 3.1-7. JAHS sample sites for the AJ and AH components of the Aquatic Studies Program during 1983
and 1984.
Site
River
Mile
Macro-
habitat
Type2
1983/1984 Sampling1
1982
DFH
Site
1982
SFH
Site
1981
Sample
Site
Fish
Distri-
bution
Site
RJHAB
Modeling
Site
IFIM
Modeling
Site
Eagles Nest Side Channel3 36.2 SC X X
Hooligan Side Channel3 36.2 SC X X
Kroto Slough Head 36.3 SS X X
Rolly Creek Mouth 39.0 T X X
X
Bear Bait Side Channel 42.9 SC X X
Last Chance Side Channel 44.4 SC X X
Rustic Wilderness Side Channel 59.5 SC X X
Caswell Creek Mouth3 63.0 T X X
X X
Island Side Channel 63.2 SC X X X
Mainstem West Bank 74.4 SC X
X
Goose 2 Side Channel 74.8 SC X X
X
Circular Side Channel 75.3 SC X
X
Sauna Side Channel 79.8 SC X
X
Sucker Side Channel3 84.8 SC X X
Beaver Dam Slough3 86.3 T X X
Beaver Dam Side Channel3 86.3 SC X X
Sunset Side Channel3 86.9 SC X
X
Sunrise Side Channel3 87.0 SC X X
Birch Slough3 89.4 T X X
X
X
Trapper Creek Side Channel 91.6 SC X X X
Whiskers Creek Slough 101.2 SS/SC X X
X
X
Whiskers Creek4 101.2 T X
X
X
Slough 3B 101.4 SS X
Mainstem at head of Whiskers
Creek Slough4 101.4 SC X
Chase Creek 106.9 T X
X
Slough 5 107.6 US X X
Oxbow I 110.0 SC/SS X
Slough 6A 112.3 US X X
X
X
Mainstem above Slough 6A4 112.4 SC X
Lane Creek4 113.6 T X
X
X
Slough 8 113.6 SS X X
X
Mainstem II 114.4 SC/SS X
X
Lower McKenzie Creek4 116.2 T X
X
Upper McKenzie Creek4 116.7 T X
X
Side Channel below Curry4 117.8 SC X
Oxbow II4 119.3 SC/SS X
Slough 8A 125.3 SS X
X X
Side Channel 10A 127.1 SC X X
Slough 9 129.2 SS/SC X
X X
Slough/Side Channel 10 133.8 SC/SS X
X
X X
Lower Side Channel 114 134.6 SC X
X
Slough 11 135.3 SS X
X
X
Upper Side Channel 114 136.2 SC X
X
Indian River - Mouth 138.6 T X
X
X
Indian River-TRM 10.1 138.6 T X
Slough 194 140.0 US X
X
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Site
River
Mile
Macro-
habitat
Type2
1983/1984 Sampling1
1982
DFH
Site
1982
SFH
Site
1981
Sample
Site
Fish
Distri-
bution
Site
RJHAB
Modeling
Site
IFIM
Modeling
Site
Slough 204 140.1 SS/SC X
X
X
Side Channel 21 140.6 SC
X
Slough 21 142.0 SS/SC
X X
Slough 22 144.3 SS/SC X X
Jack Long Creek4 144.5 T X
X
Portage Creek Mouth 148.8 T X
X
X
Portage Creek TRM 4.2 148.8 T X
Portage Creek TRM 8.0 148.8 T X
Notes:
1 Sites from RM 36.2 to RM 91.6 were sampled in 1984 (Suchanek et al. 1985). Sites from RM 101.2 to 148.8
were sampled in 1983 (Dugan et al. 1984).
2 T – Tributary
US - Upland Slough
SS - Side Slough
SC - Side Channel
3 Located within representative side channel or slough complexes mapped by Ashton & Klinger (1985).
4 Sites sampled less than 3 times in 1983.
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Table 4.1-1. Characteristics of tributaries upstream of the proposed Devils Canyon Dam as configured in the 1980s project. Source: Sautner and Stratton (1983).
Stream RM
Elev. at
Mouth
Inundated
Reach1
Ave
Width (ft)
Ave
Depth
(ft) Channel types Substrate Barriers
Len
(mi)
Grad
(%)
Cheechako 152.4 920 1.7 6.1% 20 to 30 2 to 4 rapids and waterfalls with few
pools
large boulder and cobble
Chinook 157.0 1065 1.3 5.8% 20 to 30 2 to 4 rapids and waterfalls with few
pools
large boulder and small cobble
Devil 161.4 1200 1.5 3.3% 30 to 40 2 to 4 rapids and large deep pools large boulder and cobble with smaller
rubble and gravel in pools
TRM 2.1
Fog 176.7 1375 1.3 1.4% 50 to 75 2 to 3 riffles with few pools, some
braiding near mouth
rubble and cobble Potential at
TRM 2.7
Tsusena 181.3 1435 0.4 1.6% 75 to 100 2 to 3 shallow riffles with few small
pools
large cobble and boulder embedded in
sand, small gravel in pools
TRM 3.1
Deadman 186.7 1515 2.7 4.8% 75 to 100 3 to 5 rapids with few pools Large boulder and cobble TRM 0.6
Watana 194.1 1550 8.5 1.1% 40 to 60 2 to 4 pool-riffle Gravel and rubble embedded in sand in
moderate to slow water, cobble and
boulder in faster water
EF Watana 2060 1.2 2.1% 30 to 50 2 to 3 riffle with some small
waterfalls and pools
potential at
TRM 9.4
WF Watana 2060 2.1 1.3% 30 to 50 2 to 3 riffle with few pools
Kosina 206.8 1670 4.5 2.2% 200+ 3 to 5
riffle-pool, braided in sections cobble and boulder in riffles; cobble,
rubble and boulder embedded in sand in
pools
Jay 208.5 1695 3.5 2.7% 40 to 60 2 to 3 riffle-pool gravel, cobble, and rubble often
embedded in sand
potential at
TRM 3.8
Goose 231.3 2060 1.2 2.2% 30 to 50 2 to 3 riffle-pool with some braiding
in upper reaches
rubble, cobble, and boulder in riffles,
gravel and rubble in slower water
Oshetna 233.4 2110 2.2 0.8% 100 to 125 3 to 5 meandering riffles cobble and boulder in riffles, and rubble
and gravel in slower water
Notes:
1 The inundation elevation as proposed during the 1980s was 2200.5 feet mean sea level for Watana Reservoir and 1466 feet msl for the Devils Canyon
Reservoir.
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Table 4.2-1. Black and white aerial photography available for the characterization of aquatic habitat during the 1980s.
Discharge as measured at the USGS Gold Creek gage. Source: Aaserude et al. (1985).
Mainstem Discharge (cfs) Date Scale Comments
1500 – 2000 March 1983 1 inch = 1,000 ft Ice cover
5,100 October 14, 1984 1 inch = 250 ft Open water
7,400 October 4, 1984 1 inch = 250 ft Open water
9,000 October 8, 1983 1 inch = 1,000 ft Some ice present
10,600 September 9, 1984 1 inch = 250 ft Open water
12,500 September 11, 1983 1 inch = 1,000 ft Open water
16,000 September 6, 1983 1 inch = 1,000 ft Open water
18,000 August 20, 1980 1 inch = 1,000 ft Open water
23,000 June 1, 1982 1 inch = 1,000 ft Open water
26,900 August 27, 1984 1 inch = 1,000 ft Open water
Table 4.3-1. Representative areas delineated by habitat type. Source: Ashton and Klinger-Kingsley (1985).
Representative Area Name River Miles Included
Side Channel IV 32.5 - 36.0
Willow Creek (Side Channel lll-1) 49.0 - 52.0
Caswell Creek 64.0
Sheep Creek 66.1
Goose Creek (Side Channel II-4) 68.5 - 72.5
Montana Creek (Side Channel II-1) 77.0 - 78.0
Sunshine Slough (Side Channel I-5) 84.0 - 86.5
Birch Creek Slough 88.5 - 93.0
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Table 5.1-1. Information from Buckwalter (2011) Synopsis of ADF&G’s Upper Susitna Drainage Fish Inventory, August 2011.
Stream River Mile Date Lifestage
Number of
Fish
Method
Reference
Above Devils Canyon (RM 152)
Fog Creek 176.7 8/1/2003 adults 2 helicopter/foot Buckwalter 2011, AWC Survey ID: FSS03USU01
Tsusena Creek 181.3 8/1/2003 adults 1 helicopter/foot Buckwalter 2011, AWC Survey ID: FSS03USU02
Fog Creek 176.7 8/13/2003 juveniles 5 electrofishing Buckwalter 2011, AWC Survey ID: FSS0305A01
Fog Creek Trib 176.7 8/6/2011 juveniles 8 electrofishing Buckwalter 2011, AWC Survey ID: FSS1104c01
Fog Creek 176.7 8/6/2011 redds Survey ID: FSS1104B01
Above Watana Dam Site (RM 184)
Kosina Creek 201 8/14/2003 juveniles 1 electrofishing Buckwalter 2011, AWC Survey ID: FSS0306A01
Oshetna River 225 8/14/2003 juveniles 3 electrofishing Buckwalter 2011, AWC Survey ID: FSS0306A05
Kosina Creek 201 8/15/2003 juveniles 2 electrofishing Buckwalter 2011, AWC Survey ID: FSS0307A06
Kosina Creek 201 7/27/2011 adults 1 helicopter/foot Buckwalter 2011, Survey ID: FSS1101G04
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Table 5.1-2. Chinook salmon escapement survey results from 1982 to 1985 upstream of RM 152. Surveys conducted by helicopter.
Stream
1982 1983 1984 1985 # Flights Date of Peak Count Peak Count APA Source/PDF Page # Flights Date of Peak Count Peak Count APA Source/PDF Page # Flights Date of Peak Count Peak Count APA Source/PDF Page # Flights Date of Peak Count Peak Count APA Source/PDF Page Cheechako Cr 9 6-Aug 16 589/314 2 1-Aug 25 1450/111 7 1-Aug 29 2748/60, 506 11 24-Jul 18 3412/127
Chinook Cr 5 6-Aug 5 589/314 2 1-Aug 8 1450/111 7 1-Aug 15 2748/60, 506 11 23-Aug 1 3412/128
Devil Cr 5 0 589/314 1 1-Aug 1 1450/111 6 0 2748/60, 506 11 0 3412/128
Fog Cr 0 2748/60 0 2748/60 4 21-Jul 2 2748/60, 506 3 0 3412/128
Bear Cr 0 0 2748/151 4 0 2748/506 3 0 3412/128
Tsusena Cr 0 0 2748/151 4 0 2748/507 3 0 3412/128
Deadman Cr 0 0 3 0 2748/507 0 Watana Cr 0 0 2 0 2748/507 0
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Table 5.2-1. Peak sockeye spawner counts (live plus dead) at sloughs located in the Middle Susitna River during 1981 to
1985. Source Jennings (1985), Thompson et al. (1986).
Slough RM
Peak Counts Average
Percent
Contribution 1981 1982 1983 1984 1985 Average
Slough 1 99.6 0 0 0 10 0 2 0.2%
Slough 2 100.2 0 0 0 7 0 1.4 0.2%
Slough 3B 101.4 1 0 5 20 0 5.2 0.6%
Slough 3A 101.9 7 0 0 11 0 3.6 0.4%
Slough 5 107.6 0 0 0 1 0 0.2 0.0%
Slough 6A 112.3 1 0 0 0 1 0.4 0.0%
Slough 8 113.7 0 0 0 2 0 0.4 0.0%
Bushrod 117.8 0 0 0 0 1 0.2 0.0%
Slough 8C 121.9 0 2 0 0 1 0.6 0.1%
Slough 8B 122.2 0 5 0 1 2 1.6 0.2%
Moose 123.5 0 8 22 8 0 7.6 0.9%
Slough 8A 125.1 177 68 66 128 165 120.8 14.2%
Slough B 126.3 0 8 2 9 5 4.8 0.6%
Slough 9 128.3 10 5 2 6 0 4.6 0.5%
Slough 9B 129.2 81 1 0 7 0 17.8 2.1%
Slough 9A 133.8 2 1 1 0 0 0.8 0.1%
Slough 10 133.8 0 0 1 0 0 0.2 0.0%
Slough 11 135.3 893 456 248 564 694 571 67.1%
Slough 15 137.2 0 0 0 1 0 0.2 0.0%
Slough 17 138.9 6 0 6 16 0 5.6 0.7%
Slough 19 139.7 23 0 5 11 1 8 0.9%
Slough 20 140.1 2 0 0 0 0 0.4 0.0%
Slough 21 141.1 38 53 197 122 53 92.6 10.9%
Slough 22 144.5 0 0 0 2 0 0.4 0.0%
Total 1241 607 555 926 923 850.4 100%
Table 6.2-1. Linear regression statistics for predicting the development of chum and sockeye eggs based upon average
incubation temperature. All equations were significant at p<0.001 and r-0.99. Source: Wagaard and Burger (1983).
Species Life Stage Slope Intercept
Chum 50% Hatch 1.40 3.23
100% Yolk Absorption 0.59 2.25
Sockeye 50% Hatch 0.15 3.71
100% Yolk Absorption 0.14 2.61
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Table 7.1-1. Periodicity of juvenile Chinook salmon presence in the Susitna River. Light gray indicates total duration of residence in the middle Susitna River and dark
gray represents periods of peak use. Source: Schmidt and Bingham (1983), ADF&G (1983), Schmidt et al. (1984), Jennings (1985), Trihey and Associates and Entrix
(1985), Roth et al. (1986), Stratton (1986).
Species Life Stage (Age) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Chinook
Salmon
Incubation
Fry Emergence
Rearing (0+)
Rearing (1+)
Juvenile Migration (0+)
Juvenile Migration (1+)
Table 7.2-1. Periodicity of second run sockeye salmon presence in the middle Susitna River, between the Chulitna River confluence (RM 98.5) and Devils Canyon (RM
152), by life history stage. Light gray indicates total duration of residence in the middle Susitna River and dark gray represents periods of peak use.
Species Life Stage (Age) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Sockeye
Salmon1,2
Incubation
Fry Emergence
Rearing (0+)
Rearing (1+)
Juvenile Migration (0+)
Juvenile Migration (1+)
Peak Use Off-Peak Use
Peak Use Off-Peak Use
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Table 7.3-1. Periodicity of juvenile chum salmon presence in the Susitna River. Light gray indicates total duration of residence in the middle Susitna River and dark
gray represents periods of peak use.
Species Life Stage (Age) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Chum
Salmon
Incubation
Fry Emergence
Rearing (0+)
Juvenile Migration (0+)
Table 7.4-1. Periodicity of juvenile coho salmon in the Susitna River by life history stage. Light gray indicates total duration of residence in the middle Susitna River
and dark gray represents periods of peak use.
Species Life Stage (Age) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Coho
Salmon
Incubation
Fry Emergence
Rearing (0+)
Rearing (1+)
Rearing (2+)
Juvenile Migration (0+)
Juvenile Migration (1+)
Juvenile Migration (2+)
Table 7.5-1. Periodicity of juvenile pink salmon presence in the Susitna River by life history stage. Light gray indicates total duration of residence in the middle Susitna
River and dark gray represents periods of peak use.
Species Life Stage (Age) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Pink
Salmon3
Incubation
Fry Emergence
Juvenile Migration (0+)
Peak Use Off-Peak Use
Peak Use Off-Peak Use
Peak Use Off-Peak Use
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Table 8.1-1. Fish community in the Susitna River drainage. Source: Jennings (1985), Delaney et al. (1981).
Common Name Scientific Name
Susitna River Segment
Tributaries Lakes Lower
Middle River1
Upper Lower Upper
Arctic grayling Thymallus arcticus X X X X X
Dolly Varden Salvelinus malma X X X X X
Humpback whitefish Coregonus pidschian X X X
Round whitefish Prosopium cylindraceum X X X X X
Burbot Lota lota X X X X
Longnose sucker Catostomus catostomus X X X X X
Sculpin2 Cottid X X X X X
Eulachon Thaleichthys pacificus X
Bering cisco Coregonus laurettae X
Threespine stickleback Gasterosteus aculeatus X X X
Ninespine stickleback Pungitius pungitius X
Arctic lamprey Lethenteron japonicum X X X
Chinook salmon Oncorhynchus tshawytscha X X X X X
Coho salmon Oncorhynchus kisutch X X X
Chum salmon Oncorhynchus keta X X X
Pink salmon Oncorhynchus gorbuscha X X X
Sockeye salmon Oncorhynchus nerka X X X
Rainbow trout Oncorhynchus mykiss X X X
Northern pike Esox lucius X ? X X
Lake trout Salvelinus namaycush X X
Notes:
1 The Lower Middle River is from the confluence of the Chulitna River to Devils Canyon. Upper Middle River is from Devils Creek to the proposed Watana
Dam Site.
2 Sculpin primarily include slimy sculpin (C. cognatus), but may also include coastrange sculpin (C. aleuticus), sharpnose sculpin (C. acuticeps), Pacific
staghorn sculpin (Leptocottus armatus) and possibly others.
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Table 8.1-2. Level of fishing effort at 17 DFH sites in the Lower and Middle Susitna River segments from June to September 1982. Data Source: Schmidt et al. (1983).
DFH
Location
Boat Electrofishing BP Electrofishing Beach Seine Minnow Trap Trotline
Mean Eff
(mins)
Sampling
Events
Mean Eff
(mins)
Sampling
Events
Mean Eff
(hauls)
Sampling
Events
Mean Eff
(traps)
Sampling
Events
Mean Eff
(lines)
Sampling
Events
4th of July Creek-Mouth 18.1 6 23.3 3 1.0 4 16.0 8 2.0 7
Birch Creek and Slough 24.0 5 23.0 3 2.3 6 23.5 8 2.9 8
Goose Creek 2 and Side Channel 12.7 5 10.6 3 2.3 8 21.0 8 3.0 8
Indian River-Mouth 28.8 6 2.9 2 1.0 3 15.0 8 2.1 8
Lane Creek and Slough 8 17.3 8 8.1 5 1.1 7 20.3 8 2.9 8
Portage Creek 23.3 6 0 0 13.7 6 2.0 6
Rabideaux Creek and Slough 37.2 4 2.3 1 1.5 4 22.2 6 2.7 6
Slough 11 14.1 3 2.2 3 2.3 4 21.8 8 2.8 8
Slough 19 13.0 1 2.5 4 1.2 5 14.1 8 2.0 8
Slough 20 9.6 5 2.7 4 1.8 4 17.0 8 2.3 8
Slough 21 15.5 2 8.2 4 1.8 4 18.6 8 2.5 8
Slough 6a 17.1 3 11.4 1 1.4 7 14.0 8 2.0 8
Slough 8a 13.0 6 28.8 3 1.7 7 21.0 8 3.0 8
Slough 9 13.0 1 6.4 4 1.4 7 16.4 8 2.3 8
Sunshine Creek and Side Channel 17.9 5 8.2 2 1.8 4 16.5 8 2.5 8
Whiskers Creek and Slough 24.8 6 14.8 2 2.3 6 25.3 8 3.4 8
Whitefish Slough 13.2 5 0 1.0 5 9.6 7 2.0 5
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Table 8.1-2. Continued.
DFH
Location
Dip Net Fish Trap Hoop Net Set Gillnet Hook and Line
Mean Eff
(nets)
Sampling
Events
Mean Eff
(traps)
Sampling
Events
Mean Eff
(nets)
Sampling
Events
Mean Eff
(nets)
Sampling
Events
Mean Eff
(hrs)
Sampling
Events
4th of July Creek-Mouth 0 0 0 0 3.2 5
Birch Creek and Slough 1.7 3 0 1.0 2 0 0
Goose Creek 2 and Side Channel 0 0 0 0 0
Indian River-Mouth 1.0 1 0 0 0 2.0 1
Lane Creek and Slough 8 1.0 2 3.0 1 0 0 1.0 1
Portage Creek 0 0 0 0 1.7 3
Rabideaux Creek and Slough 1.0 4 0 0 0 0
Slough 11 0 3.0 1 0 2.0 1 0
Slough 19 1.0 4 0 0 0 0
Slough 20 0 0 0 0 0
Slough 21 1.0 1 0 0 0 0
Slough 6a 1.0 1 2.0 1 1.0 1 0 0
Slough 8a 1.3 3 0 0 2.0 2 0
Slough 9 0 0 0 0 0
Sunshine Creek and Side Channel 0 0 0 0 0.4 1
Whiskers Creek and Slough 1.0 2 0 0 0 2.0 1
Whitefish Slough 1.0 2 0 1.0 1 1.0 1 0
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Table 8.2-1. Estimated Arctic grayling population sizes in tributaries to the upper Susitna River during 1981 and 1982.
Source: Delaney et al. (1981b), Sautner and Stratton (1983).
Stream
19811 19821
Point
Estimate
(fish)
95% Confidence Interval
(fish)
Point Estimate
(fish)
Point Estimate
(fish/mile)
Oshetna River 2,017 1,525 - 2,976 2,426 1,103
Goose Creek 1,327 1,016 - 1,913 949 791
Jay Creek 1,089 868 - 1,462 1,592 455
Kosina Creek 2,787 2,228 - 3,720 5,544 1,232
Deadman Creek 979 604 - 2,575 734 1,835
Tsusena Creek 1,000 743 - 1,530
Fog Creek 176 115 - 369 440
Watana Creek 3,925 324
Upper Susitna River 10,279 9,194 - 11,654 16,3462
Notes:
1 Fish densities were not reported for 1981. Confidence intervals were not reported for 1982.
2 Total of point estimates from 1982 plus 1981 point estimates for Tsusena and Fog creeks.
Table 9.1-1. Tributaries evaluated for passage by adult salmon. Source: Trihey (1983), Ashton and Trihey (1985).
Tributary River Mile Gradient
Alexander Creek 9.1 Low
Deshka River 40.6 Low
Willow Creek 49.1 Steep
Little Willow Creek 50.5 Steep
Kashwitna River 61.0 Steep
Caswell Creek 64.0 Low
Sheep Creek 66.1 Low
Goose Creek 72.0 Steep
Montana Creek 77.0 Steep
Rabideaux Creek 83.1 Low
Sunshine Creek 85.1 Low
Birch Creek 89.2 Low
Trapper Creek 91.5 Low
Indian River 138.7 -
Portage Creek 148.9 -
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14. FIGURES
Figure. S-1. Spawning habitat utilization by anadromous salmon species and average run size in the middle Susitna
River. Large arrows indicate primary spawning habitat and thin arrows indicate secondary spawning habitat. Source:
Trihey and Entrix (1985) as modified from Sautner et al. (1984). Run size information from Barrett et al. (1985).
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Figure 2.1-1. Susitna River basin map showing field stations and major glacial streams. Source: ADF&G (1983).
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Figure 3.1-1. Habitat types identified in the middle reach of the Susitna River during the 1980s studies (adapted from
ADF&G 1983; Trihey 1982).
Side
Slough
Upland
Slough
Tributary Tributary
Mouth
Lake
Hyporheic
Zone
Side Channel
Mainstem
Channel
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Figure 3.1-2. Sampling effort at 39 habitat locations sites from May to mid-October 1981. Source: Delaney et al. (1981).
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Figure 3.1-3. Map of Designated Fish Habitat (DFH) sites sampled on the Susitna River, June through September 1982.
Source: Schmidt et al. (1983).
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Figure 3.1-4. Sampling effort at 17 DFH sites during the 1982 open water season. Source: Schmidt et al. (1983).
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Figure 3.1-5. Hypothetical slough with delineated habitat zones. Source: Estes and Schmidt (1983).
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Figure 3.1-6. Sampling effort at 225 mainstem Selected Fish Habitat sites during 1982. Data Source: Schmidt et al. (1983).
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Figure 3.1-7. Typical arrangement of transects, grids, and cells at a JAHS site. Source: Dugan et al. (1984).
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Figure 4.1-1. Gradient profile of the Susitna River and the major tributaries within the impoundment areas of the proposed 1980 project. Profile includes the five mile
reach of each tributary immediately above the proposed impoundment elevation and identifies known. Source: Sautner and Stratton (1983).
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Figure 4.1-2. Discharge measured at six tributary streams in the Upper Susitna River during 1982. All discharges were
taken in proximity of the mouth with the exception of Deadman Creek where it was taken approximately three miles
upstream from the mouth. Discharge not measured at Deadman Creek during mid-September. Source: Sautner and
Stratton (1983).
Figure 4.1-3. Typical substrate observed in Tsusena and Kosina Creeks during 1982. Ruler is 12 inches long. Source:
Sautner and Stratton (1983).
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Figure 4.2-1. Relative amounts of habitat types in different areas of the Susitna River at seven mainstem discharges. Source: Klinger-Kingsley et al. (1985).
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Figure 4.3-1. Amount of wetted surface area within mainstem channel (top) and side channel complexes (bottom) at five
mainstem discharge levels for four lower river segments. Source: Ashton and Klinger-Kingsley (1985).
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Figure 4.3-2. Proportion of area accounted for by nine habitat types delineated at five mainstem discharge levels for five sites in the lower Susitna River. Data Source:
Ashton and Klinger-Kingsley (1985).
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Figure 4.3-3. Area (ft2 on log scale) accounted for by nine habitat types delineated at five mainstem discharge levels for five sites in the lower Susitna River. Data
Source: Ashton and Klinger-Kingsley (1985).
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Figure 5.1-1. Deshka River Chinook salmon escapement. Source: Fair et al. (2010).
Figure 5.1-2. Escapement of Chinook salmon to Susitna River index streams other than the Deshka River. Source: Fair
et al. (2010).
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Figure 5.1-3. Escapement to Sunshine, Talkeetna, and Curry stations based upon mark-recapture techniques. No
escapement estimates were made for Talkeetna Station during 1985. Source: Barrett et al. (1983), Barrett et al. (1984),
Barrett et al. (1985), Thompson et al. (1986).
Figure 5.1-4. Distribution of Chinook Salmon spawning in the Susitna River 1976 to 1984. Source: Jennings (1985).
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Figure 5.1-5. Distribution of Chinook salmon spawning in the Middle River 1982 to 1985. Sources: Thompson et al.
(1986); Barrett (1985, 1984, 1983). Age of Return.
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Figure 5.1-6. Age of return for Chinook salmon collected at the Sunshine, Talkeetna, and Curry Stations during 1981 to
1985. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.1-7. Upstream migration timing of adult Chinook salmon in the Susitna River based upon fishwheel catch per
unit effort. Source: ADF&G (1984).
Figure 5.1-8. Substrate utilization curve for Chinook salmon based upon measurements at 265 redds. Source: Vincent-
Lang et al. (1984).
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Figure 5.1-9. Best depth (top) and velocity (bottom) Chinook salmon utilization curves based upon measurements at 265
redds. Source: Vincent-Lang et al. (1984b).
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Figure 5.2-1. Escapement of sockeye salmon to the Yentna River 1981 to 2008 based upon expansion and apportionment
of sonar counts. Source: http://www.adfg.alaska.gov/sf/FishCounts/
Figure 5.2-2. Second run sockeye salmon escapement estimates to the Susitna River 1981 to 1985. No estimates for the
following stations and years Susitna/Flathorn (1982, 1983), Yentna (1982, 1985), and Talkeetna (1985). *: Estimate based
upon apportionment of sonar counts. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985),
Thompson et al. (1986).
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Figure 5.2-3. Location of fish wheel capture sites, weirs, and radio-tracking stations in the Susitna River drainage, and
the terminal distribution of radio-tagged sockeye salmon based on aerial surveys, 2007 (top) and 2008 (bottom). Terminal
location does not necessarily mean a spawning location Source: Yanusz et al. (2011a, 2011b).
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Figure 5.2-4. Weighted terminal distribution of sockeye salmon in the Susitna River system above Sunshine during 2007
(top) and 2008 (bottom). Source: Yanusz et al. (2011a, 2011b).
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Figure 5.2-5. Distribution of sockeye spawning in Middle Susitna River sloughs. Source: Jennings (1985), Thompson et
al. (1986).
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Figure 5.2-6. Age of return for sockeye salmon collected at the Sunshine, Talkeetna, and Curry Stations during 1981 to
1985. First run and second run fish were not distinguished at all stations during all years. First run fish are not known to
spawn in the Middle Susitna River. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985),
Thompson et al. (1986).
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Figure 5.2-7. Upstream migration timing of second run adult sockeye salmon in the Susitna River based upon fishwheel
catch per unit effort. Source: Jennings (1985).
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Figure 5.2-8. Best depth (top) and velocity (bottom) sockeye salmon utilization curves based upon measurements at 81
redds. Source: Vincent-Lang et al. (1984a).
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Figure 5.2-9. Substrate utilization curve for sockeye salmon based upon measurements at 81 redds. Source: Vincent-
Lang et al. (1984).
Figure 5.3-1. Chum salmon escapement estimates to the Susitna River 1981 to 1985. No estimates for the following
stations and years Susitna/Flathorn (1982, 1983), Yentna (1982, 1985), and Talkeetna (1985). *: Estimate based upon
apportionment of sonar counts. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985),
Thompson et al. (1986).
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Figure 5.3-2. Spawning distribution of 210 chum salmon radio-tagged at Flathorn during 2009. Source: Merizon et al.
(2010).
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Figure 5.3-3. Chum salmon spawning distribution among tributaries and sloughs in the Middle Susitna River based upon
peak counts. Source: Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.3-4. Age of return for chum salmon collected at the Sunshine, Talkeetna, and Curry Stations during 1981 to
1985. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.3-5. Upstream migration timing of adult chum salmon in the Susitna River based upon fishwheel catch per unit
effort. Source: Jennings (1985).
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Figure 5.3-6. Best depth (top) and velocity (bottom) chum salmon utilization curves based upon measurements at 333
redds. Source: Vincent-Lang et al. (1984a).
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Figure 5.3-7. Substrate utilization curve for chum salmon based upon measurements at 33 redds. Source: Vincent-Lang
et al. (1984a).
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Figure 5.4-1. Coho salmon escapement estimates to the Susitna River 1981 to 1985. No estimates for the following
stations and years Susitna/Flathorn (1982, 1983), Yentna (1982, 1985), and Talkeetna (1985). *: Estimate based upon
apportionment of sonar counts. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985),
Thompson et al. (1986)
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.
Figure 5.4-2. Spawning distribution of 275 coho salmon radio-tagged at Flathorn during 2009. Source: Merizon et al.
(2010).
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Figure 5.4-3. Coho salmon spawning distribution among tributaries in the Middle Susitna River based upon peak counts.
Source: Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.4-4. Age of return for coho salmon collected at the Sunshine, Talkeetna, and Curry Stations during 1981 to
1985. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.4-5. Upstream migration timing of adult coho salmon in the Susitna River based upon fishwheel catch per unit
effort. Source: Jennings (1985).
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Figure 5.5-1. Pink salmon escapement estimates to the Susitna River 1981 to 1985. No estimates for the following stations
and years Susitna/Flathorn (1982, 1983), Yentna (1982, 1985), and Talkeetna (1985). *: Estimate based upon
apportionment of sonar counts. Source: ADF&G (1981), Barrett et al. (1983), ADF&G (1984), Barrett et al. (1985),
Thompson et al. (1986).
Figure 5.5-2. Pink salmon escapement estimates to the Deshka River 1996 to 2012. Source:
http://www.adfg.alaska.gov/sf/FishCounts/
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Figure 5.5-3. Pink salmon spawning distribution among tributaries in the Middle Susitna River based upon peak
counts.Source: Barrett et al. (1985), Thompson et al. (1986).
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Figure 5.5-4. Upstream migration timing of adult pink salmon in the Susitna River based upon fishwheel catch per unit
effort. Source: Jennings (1985).
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Figure 6.1-1. Percent survival of chum salmon eggs in artificial redds at eight sites during the winter of 1984-1985.
Source: Vining et al. (1985).
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Figure 6.1-2. Percent size composition of fine substrate (<0.08 in. diameter) of McNeil samples collected in various
habitat types in the middle Susitna River, Alaska. Source: Vining et al. (1985).
Figure 6.1-3. Percent size composition of fine substrate (<0.08 in. diameter) in McNeil samples collected at chum salmon
redds during May 1984 in study sites of middle Susitna River, Alaska. Source Vining et al. (1985).
0
4
8
12
16
20
24
28
Fourth of July
Cr
Slough 10 Slough 11(B)Upper Side
Channel 11
Mainstem
HRM 138.9
Side Channel
21
Slough 21Percent Fines (<0.08 inches diameter) Habitat Type
0.08 - 0.02 0.02 - 0.002 <0.002
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Figure 6.1-4. Relationship between percent survival of salmon embryos and the percent of fine substrate (<0.08 in.
diameter) within Whitlock-Vibert Boxes removed from artificial redds within selected habitats of the middle Susitna
River, Alaska. Source: Vining et al. (1985).
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Figure 6.2-1. Mean daily intergravel and surface water temperature data from a spawning site in Slough 8A. Source:
Trihey (1982).
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Figure 6.2-2. Summary (mean and range) of intragravel and corresponding surface water temperature data collected
along left (L) and right (R) banks (looking upstream). Source: Hoffman et al. (1983).
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Figure 6.2-3. Embryonic development, hatching, yolk sac absorption, and emergence data for chum salmon at three sloughs, winter, 1982-1983. Numbers in parentheses
are the percentages of individuals sampled which were at the indicated stage. Source: Hoffman et al. (1983).
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Figure 6.2-4. Embryonic development, hatching, yolk sac absorption, and emergence data for sockeye salmon at three sloughs, winter, 1982-1983. Numbers in
parentheses are the percentages of individuals sampled which were at the indicated stage. Source: Hoffman et al. (1983).
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Figure 6.2-5. Comparison of the timing of development of chum salmon embryos placed within slough, side channel and mainstem habitats during the winter of 1984-
1985. Source: Vining et al. (1985).
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Figure 6.2-6. Temperature regimes for the Susitna River egg-incubation study which simulated the main-stem river RM
136 (MS), Slough 8A (S2), an intermediate regime (S1), and a constant 4°C regime (4°). Source: Wangaard and Burger
(1983).
Figure 6.2-7. Accumulated temperature units beginning September 3 at four different temperature regimes for the
Susitna River egg-incubation study. The four regimes simulated the Susitna main stem (MS), Slough 8A (S2), an
intermediate regime (S1), and 4°C Constant (4°). Source: Wangaard and Burger (1983).
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Figure 6.2-8. Left: days from fertilization to 50 percent hatch (cross- hatched bars) and complete yolk absorption (open
bars). Right: Accumulated temperature units to reach 50 percent hatch (cross-hatched bars) and complete yolk
absorption (open bars). Incubation occurred at four different temperature regimes which simulated the Susitna main
stem (MS), Slough 8A (S2), an intermediary (Sl), and constant 4°C regime (4°). Data were pooled from three fertilization
dates in September and from study replicates. Source: Wangaard and Burger (1983).
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Figure 6.2-9. Alevin growth (total length) from 50 percent hatch to complete yolk absorption for chum and sockeye
salmon incubated at three different temperature regimes. The regimes simulated the Susitna main stem (MS), Slough 8A
(S2), and an intermediary (S1). (Data are based on a fertilization date of September 15. Data from replicates were
pooled.). Source: Wagaard and Burger (1983).
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Figure 7.1-1. Year of ocean entry by Chinook salmon based upon scale analysis of adults returning in 1983 and 1984.
Source: ADF&G (1984), Barrett et al. (1985).
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Figure 7.1-2. Chinook salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the mouth of Indian
River. Source: Roth et al. (1986).
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Figure 7.1-3. Chinook salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.1-4. Chinook salmon (age 1+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.1-5. Mean length of Chinook fry captured at outmigrant traps during 1984 and 1985. Source: Roth and Stratton
1985, Roth et al. (1986).
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Figure 7.1-6. Mean length of Chinook Age 1+ captured at outmigrant traps during 1984. Source: Roth and Stratton
1985.
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Figure 7.1-7. Density distribution and juvenile Chinook salmon by macrohabitat type on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Percentages are based on mean catch per
cell. Source: Dugan et al. (1984).
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Figure 7.1-8. Seasonal distribution and relative abundance of juvenile Chinook salmon on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Source: Dugan et al. (1984).
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Figure 7.2-1. Year of ocean entry by sockeye salmon based upon scale analysis of adults returning in 1983 and 1984.
Source: ADF&G (1984), Barrett et al. (1985).
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Figure 7.2-2. Sockeye salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna Station
outmigrant traps, 1984. Source: Roth and Stratton (1985).
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Figure 7.2-3. Sockeye salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.2-4. Sockeye salmon (age 1+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.2-5. Mean length of sockeye salmon fry and Age 1+ captured at outmigrant traps during 1984 and 1985. Source:
Roth and Stratton 1985, Roth et al. (1986).
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Figure 7.2-6. Density distribution and juvenile sockeye salmon by macrohabitat type on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Percentages are based on mean catch per
cell. Source: Dugan et al. (1984).
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Figure 7.2-7. Seasonal distribution and relative abundance of juvenile sockeye salmon on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Source: Dugan et al. (1984).
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Figure 7.3-1. Chum salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper)
and Flathorn (lower) station outmigrant traps, 1984. Source: Roth and Stratton (1985).
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Figure 7.3-2. Chum salmon (Age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.3-3. Mean length of sockeye salmon fry captured at outmigrant traps during 1984. Source: Roth and Stratton
(1985).
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Figure 7.3-4. Density distribution and juvenile chum salmon by macrohabitat type on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Percentages are based on mean catch per
cell. Source: Dugan et al. (1984).
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Figure 7.3-5. Seasonal distribution and relative abundance of juvenile chum salmon on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Source: Dugan et al. (1984).
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Figure 7.4-1. Year of ocean entry by coho salmon based upon scale analysis of adults returning in 1983 and 1984. Source:
ADF&G (1984), Barrett et al. (1985).
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Figure 7.4-2. Coho salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the mouth of Indian
River. Source: Roth et al. (1986).
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Figure 7.4-3. Coho salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.4-4. Coho salmon (age 0+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1984. Source: Roth and Stratton (1985).
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Figure 7.4-5. Coho salmon (Age 1+) daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper
figure) and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.4-6. Mean length of coho fry captured at outmigrant traps during 1984 and 1985. Source: Roth and Stratton
(1985), Roth et al. (1986).
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Figure 7.4-7. Mean length of coho salmon Age 1+ captured at outmigrant traps during 1984 and 1985. Source: Roth and
Stratton (1985), Roth et al. (1986).
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Figure 7.4-8. Density distribution and juvenile coho salmon by macrohabitat type on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Percentages are based on mean catch per
cell. Source: Dugan et al. (1984).
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Figure 7.4-9. Seasonal distribution and relative abundance of juvenile coho salmon on the Susitna River between the
Chulitna River confluence and Devils Canyon, May through November 1983. Source: Dugan et al. (1984).
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Figure 7.5-1. Pink salmon fry daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper) and
Flathorn (lower) station outmigrant traps, 1984. Source: Roth and Stratton (1985).
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Figure 7.5-2. Pink salmon fry daily catch per unit effort and cumulative catch recorded at the Talkeetna (upper figure)
and Flathorn (lower figure) stationary outmigrant traps, 1985. Source: Roth et al. (1986).
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Figure 7.6-1. Stomach contents of Chinook, sockeye, and coho salmon juveniles during summer and fall 1977. Source:
Riis and Friese (1977).
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Figure 7.6-2. Frequency of food items by taxonomic group and guild within stomach contents of 72 juvenile Chinook
salmon collected during 1984. Source: Hansen and Richards (1985).
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Figure 8.2-1. Total catch of rainbow trout at DFH sites within the middle and lower Susitna River segments during 1982. Data from Schmidt et al. (1983).
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Figure 8.2-2. Total catch of Artic grayling at DFH sites in the Lower and Middle Susitna River during 1982. Data Source: Schmidt et al. (1983).
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Figure 8.2-3. Total catch of burbot at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-4. CPUE of burbot at DFH sites during 1982. Data Source: Schmidt et al. (1983).
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Figure 8.2-5. Total catch of round whitefish at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-6. Total catch of humpback whitefish at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-7. Total catch of longnose sucker at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-8. Total catch of Dolly Varden at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-9. Total catch of threespine stickleback at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-10. Mean hourly fishwheel catch of Bering cisco by two day periods at Sunshine Station. Source: Barrett et al.
(1983).
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FERC Project No. 14241 Page 202 February 2013
Figure 8.2-11. Mean CPUE of prespawning eulachon, tidal ranges, and temperature at the Susitna River estuary, 1982. Source: Barrett et al. (1984).
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Figure 8.2-12. Frequency distributions of instantaneous water depths (top) and velocities (bottom) measured at sites at
which eulachon spawning habitat surveys were conducted during1982 and 1983. Source: Vincent-Lang and Queral
(1984).
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Figure 8.2-13. Total catch of slimy sculpin at DFH sites during 1982 by gear type. Data Source: Schmidt et al. (1983).
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Figure 8.2-14. Catch per unit effort of Artic grayling by hook and line in tributaries to the Upper Susitna River during 1981 and 1982.The absence of a line at zero
indicates no sampling occurred at that site and period. Data Source: Delaney et al. (1981), Sautner and Stratton (1983).
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Figure 8.2-15. Total catch of burbot by trotlines during 1981 (top) at tributary mouths and CPUE of burbot at mainstem
sites in the Upper Susitna River during 1982 (bottom). Data Sources: Delaney et al. (1981), Sautner and Stratton (1983).
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Figure 8.2-16. Bathymetric map of Sally Lake. Source: Sautner and Stratton (1983).
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Figure 8.3-1. Age and length of rainbow trout collected in the Lower and Middle Susitna River during the open water
seasons of 1981, 1982, and 1983. Data Source: Delaney et al. (1981a), Schmidt et al. (1983, 1984).
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Figure 8.3-2. Age and length of longnose sucker collected in the lower, middle, and upper Susitna River during the open
water seasons of 1981, 1982, and 1983. Data Source: Delaney et al. (1981a, 1981c), Schmidt et al. (1983, 1984), Sautner
and Stratton (1983).
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Figure 8.3-3. Age and length of longnose sucker collected in the lower, middle, and upper Susitna River during the open
water seasons of 1981, 1982, and 1983. Data Source: Delaney et al. (1981a, 1981c), Schmidt et al. (1983, 1984), Sautner
and Stratton (1983).
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Figure 8.3-4. Age and length of longnose sucker collected in the lower, middle, and upper Susitna River during the open
water seasons of 1981 and 1982. Data Source: Delaney et al. (1981a, 1981c), Schmidt et al. (1983), Sautner and Stratton
(1983).
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FERC Project No. 14241 Page 212 February 2013
Figure 8.3-5. Age and length of round whitefish collected in the lower, middle, and upper Susitna River during the open
water seasons of 1981, 1982, and 1983. Data Source: Delaney et al. (1981a, 1981c), Schmidt et al. (1983, 1984).
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FERC Project No. 14241 Page 213 February 2013
Figure 8.3-6. Age and length of humpback whitefish collected in the Lower and Middle Susitna River during the open
water seasons of 1981, 1982, and 1983. Data Source: Delaney et al. (1981a, 1981c), Schmidt et al. (1983, 1984).
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Figure 8.3-7. Age and length of Bering cisco collected in the Lower Susitna River during the open water seasons of 1981.
Data Source: Delaney et al. (1981a).
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Figure 8.3-8. Length frequency of Dolly Varden (top) and Arctic lamprey (bottom) collected in the Susitna River
downstream of Devils Canyon during the open water season of 1981. Source: Delaney et al. (1981a).
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Figure 9.2-1. Chum spawning areas in Slough 9 during 1982. PR indicates downstream end of critical passage reaches. Source: Sautner et al. (1984).
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Figure 9.2-2. Thalweg profile of Slough 9. Source: Sautner et al. (1984).
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Figure 11.1-1. Velocity habitat suitability indices for benthic invertebrate guilds based upon sampling in the Middle Susitna River during 1984. Source: Hansen and
Richards (1985).
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FERC Project No. 14241 Page 219 February 2013
Figure 11.1-2. Substrate habitat suitability indices for benthic invertebrate guilds based upon sampling in the Middle Susitna River during 1984. Source: Hansen and
Richards (1985).
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Figure 11.1-3. Projections of gross surface area and WUA of burrower, swimmer, clinger, and sprawler invertebrate habitat as a function of site flow and mainstem
discharge for the Slough 9 modeling site. Source (Hansen and Richards 1985).
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Figure 11.3-1. Levels of orthophosphate (top) and nitrate (bottom) measured at seven stations. Source: Harza-Ebasco
(1985).
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Figure 11.3-2. Turbidity and temperature measured at the Gold Creek Station and discharge measured at the Talkeetna
Station during 1984. Source: Harza-Ebasco (1985).
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Figure 11.3-3. Range of turbidity during breached and unbreached conditions at twelve side sloughs and side channels.
Source: Harza-Ebasco (1985).
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Figure 11.3-4. Seasonal water temperature in the Upper Susitna River during 1980 (top) and summary of discrete water
temperature measurements at seven stations along the Susitna River (bottom). Source: Harza-Ebasco (1985).
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Figure 11.3-5. Temperature gradient in the Susitna River from RM 26 to 291. Source: Harza-Ebasco (1985).
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APPENDIX 1. INDEX OF LOCATION NAMES AND RIVER MILE
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FERC Project No. 14241 Appendix 1 - Page 1 February 2013
Sorted By River Mile
Sorted By Location Name
Location Name River Mile
Location Name River Mile
Alexander Creek 10.1
Alexander Creek 10.1
Flathorn Station 18.2
Anderson Creek 23.8
Anderson Creek 23.8
Answer Creek 84.0
Susitna Station 25.5
Birch Creek 88.4
Kroto Slough Mouth 30.1
Birch Creek Slough 88.4
Yentna River 30.1
Byers Creek (Chulitna R) 98.6
Mainstem Susitna Slough 31.0
Cache Creek 96.0
Mid Kroto Slough 36.3
Cache Creek Slough 95.5
Deshka River 40.6
Caswell Creek 63.0
Delta Islands 44.0
Chase Creek 106.4
Little Willow Creek 50.5
Cheechako Creek 152.4
Rustic Wilderness 58.1
Chinook Creek 157.0
Kashwitna River 61.0
Chulitna River 98.6
Caswell Creek 63.0
Curry Station 120.0
Slough West Bank 65.6
Dead Horse Creek 120.9
Sheep Creek Slough 66.1
Deadman Creek 186.7
Goose Creek 72.0
Delta Islands 44.0
Montana Creek 77.0
Deshka River 40.6
Sunshine Station 80.0
Devil Creek 161.0
Rabideaux Creek Slough 83.1
Devils Canyon Back Eddy 150.0
Parks Highway Bridge 83.9
Fat Canoe Island 147.0
Answer Creek 84.0
Fifth of July Creek 123.7
Question Creek 84.1
Fish Creek (Talkeetna R) 97.2
Sunshine Creek 85.7
Flathorn Station 18.2
Birch Creek Slough 88.4
Fog Creek 176.7
Birch Creek 88.4
Fourth of July Creek 131.1
Cache Creek Slough 95.5
Gash Creek 111.6
Cache Creek 96.0
Gold Creek 136.7
Fish Creek (Talkeetna R) 97.2
Gold Creek Bridge 136.7
Talkeetna River 97.2
Goose Creek 72.0
Byers Creek (Chulitna R) 98.6
Goose Creek 231.3
Troublesome Creek (Chulitna R) 98.6
Indian River 138.6
Swan Lake (Chulitna R) 98.6
Jack Long Creek 144.5
Chulitna River 98.6
Jay Creek 208.5
Slough 1 99.6
Kashwitna River 61.0
Slough 2 100.2
Kosina Creek 206.8
Whiskers Creek Slough 101.2
Kroto Slough Mouth 30.1
Whiskers Creek 101.4
Lane Creek 113.6
Slough 3B 101.4
Little Portage Creek 117.7
Slough 3A 101.9
Little Willow Creek 50.5
Talkeetna Station 103.0
Lower McKenzie Creek 116.2
Slough 4 105.2
Mainstem Susitna Slough 31.0
Chase Creek 106.4
Mid Kroto Slough 36.3
Slough 5 107.6
Montana Creek 77.0
Slough 6 108.2
Moose Slough 123.5
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FERC Project No. 14241 Appendix 1 - Page 2 February 2013
Sorted By River Mile
Sorted By Location Name
Location Name River Mile
Location Name River Mile
Oxbow I 110.2
Oshetna River 233.4
Slash Creek 111.5
Oxbow I 110.2
Gash Creek 111.6
Parks Highway Bridge 83.9
Slough 6A 112.3
Portage Creek 148.9
Slough 7 113.2
Question Creek 84.1
Lane Creek 113.6
Rabideaux Creek Slough 83.1
Slough 8 113.7
Rustic Wilderness 58.1
Lower McKenzie Creek 116.2
Sheep Creek Slough 66.1
Upper McKenzie Creek 116.7
Sherman Creek 130.8
Little Portage Creek 117.7
Side Channel 10A 132.1
Curry Station 120.0
Skull Creek 124.7
Dead Horse Creek 120.9
Slash Creek 111.5
Susitna Side Channel 121.6
Slough 1 99.6
Slough 8D 121.8
Slough 10 133.8
Slough 8C 121.9
Slough 10 133.8
Slough 8B 122.2
Slough 10 Side Channel 133.7
Moose Slough 123.5
Slough 11 135.3
Fifth of July Creek 123.7
Slough 12 135.4
Slough A prime 124.6
Slough 13 135.9
Slough A 124.7
Slough 14 135.9
Skull Creek 124.7
Slough 15 137.2
Slough 8A 125.1
Slough 16B 137.3
Slough B 126.3
Slough 17 138.9
Slough 9 128.3
Slough 18 139.1
Slough 9B 129.2
Slough 19 139.7
Sherman Creek 130.8
Slough 2 100.2
Fourth of July Creek 131.1
Slough 20 140.0
Side Channel 10A 132.1
Slough 21 141.1
Slough 10 Side Channel 133.7
Slough 21 Side Channel 140.5
Slough 10 133.8
Slough 21A 144.3
Slough 9A 133.8
Slough 22 144.3
Slough 10 133.8
Slough 3A 101.9
Slough 11 135.3
Slough 3B 101.4
Slough 12 135.4
Slough 4 105.2
Slough 13 135.9
Slough 5 107.6
Slough 14 135.9
Slough 6 108.2
Gold Creek 136.7
Slough 6A 112.3
Gold Creek Bridge 136.7
Slough 7 113.2
Slough 15 137.2
Slough 8 113.7
Slough 16B 137.3
Slough 8A 125.1
Indian River 138.6
Slough 8B 122.2
Slough 17 138.9
Slough 8C 121.9
Slough 18 139.1
Slough 8D 121.8
Slough 19 139.7
Slough 9 128.3
Slough 20 140.0
Slough 9A 133.8
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FERC Project No. 14241 Appendix 1 - Page 3 February 2013
Sorted By River Mile
Sorted By Location Name
Location Name River Mile
Location Name River Mile
Slough 21 Side Channel 140.5
Slough 9B 129.2
Slough 21 141.1
Slough A 124.7
Slough 21A 144.3
Slough A prime 124.6
Slough 22 144.3
Slough B 126.3
Jack Long Creek 144.5
Slough West Bank 65.6
Fat Canoe Island 147.0
Sunshine Creek 85.7
Portage Creek 148.9
Sunshine Station 80.0
Devils Canyon Back Eddy 150.0
Susitna Side Channel 121.6
Cheechako Creek 152.4
Susitna Station 25.5
Chinook Creek 157.0
Swan Lake (Chulitna R) 98.6
Devil Creek 161.0
Talkeetna River 97.2
Fog Creek 176.7
Talkeetna Station 103.0
Tsusena Creek 181.3
Troublesome Creek (Chulitna R) 98.6
Deadman Creek 186.7
Tsusena Creek 181.3
Watana Creek 194.1
Upper McKenzie Creek 116.7
Kosina Creek 206.8
Watana Creek 194.1
Jay Creek 208.5
Whiskers Creek 101.4
Goose Creek 231.3
Whiskers Creek Slough 101.2
Oshetna River 233.4
Yentna River 30.1