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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Study of fish distribution and abundance in the middle and lower Susitna
River study, Study plan Section 9.6 : Initial study report
SuWa 207
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Prepared by R2 Resource Consultants Inc., LGL Alaska Research Associates, Inc., Golder
Associates Inc. & HDR, Inc.
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Draft initial study report
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Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 207
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2014]
Date published:
February 2014
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Study plan Section 9.6
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Draft
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740 p. in various pagings
(including all parts)
Related work(s):
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Notes:
The following parts of Section 9.6 appear in separate files: Main report ; Appendix A ; Appendix B ;
Appendix C ; Appendices D-F.
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/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Study of Fish Distribution and Abundance in the
Middle and Lower Susitna River Study
Study Plan Section 9.6
Initial Study Report
Prepared for
Alaska Energy Authority
Prepared by
R2 Resource Consultants Inc.
LGL Alaska Research Associates, Inc.
Golder Associates Inc. &
HDR, Inc.
February 2014 Draft
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i February 2014 Draft
TABLE OF CONTENTS
Executive Summary ...................................................................................................................... x
Introduction............................................................................................................................ 1 1.
Study Objectives .................................................................................................................... 2 2.
Study Area .............................................................................................................................. 3 3.
Methods .................................................................................................................................. 4 4.
Study Site Selection ....................................................................................................... 4 4.1.
4.1.1. Early Life History Sites .......................................................................................... 4
4.1.2. Fish Distribution and Abundance Sites................................................................... 5
4.1.3. Rotary Screw Trap Sites ......................................................................................... 8
4.1.4. PIT Interrogation Antenna Sites ............................................................................. 9
4.1.5. Fixed Radio Telemetry Sites ................................................................................... 9
4.1.6. Winter Study Sites ................................................................................................ 10
4.1.7. Variances from Study Plan ................................................................................... 10
Sampling Frequency..................................................................................................... 13 4.2.
4.2.1. Variances from Study Plan ................................................................................... 14
Fish Sampling Approach .............................................................................................. 14 4.3.
Objective 1: Fish Distribution, Relative Abundance, and Habitat Associations ........ 15 4.4.
4.4.1. Task A: Fish Distribution Surveys ........................................................................ 15
4.4.2. Task B: Relative Abundance ................................................................................ 16
4.4.3. Task C: Fish Habitat Associations ........................................................................ 17
4.4.4. Variances from Study Plan ................................................................................... 18
Objective 2: Seasonal Movements ............................................................................... 20 4.5.
4.5.1. Task A: Document the timing of downstream movement and catch for all fish
species using out-migrant traps. ............................................................................ 20
4.5.2. Task B: Describe seasonal movements using biotelemetry. ................................. 20
4.5.3. Variances from Study Plan ................................................................................... 21
Objective 3: Early Life History .................................................................................... 23 4.6.
4.6.1. Task A: Describe emergence timing of salmonids. .............................................. 23
4.6.2. Task B: Determine movement patterns and timing of juvenile salmonids from
spawning to rearing habitats. ................................................................................ 23
4.6.3. Task C: Determine juvenile salmonid diurnal behavior over season. .................. 23
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii February 2014 Draft
4.6.4. Task D: Collect baseline data to support the Fish Stranding and Trapping Study.
24
4.6.5. Variances from Study Plan ................................................................................... 24
Objective 4: Document Winter Movements and Timing and Location of Spawning for 4.7.
Burbot, Humpback Whitefish, and Round Whitefish .................................................. 24
Objective 5: Document the Seasonal Size/Life stage Structure, Growth, and Condition 4.8.
of Juvenile Anadromous and Resident Fish by Habitat Type ...................................... 24
4.8.1. Variances from Study Plan ................................................................................... 25
Objective 6: Document the Seasonal Distribution, Relative Abundance, and Habitat 4.9.
Associations of Invasive Species (Northern Pike) ....................................................... 26
Objective 7: Collect Tissue Samples from Juvenile Salmon and All Resident and 4.10.
Non-Salmon Anadromous Fish .................................................................................... 26
Winter Sampling Approach.......................................................................................... 26 4.11.
Fish Sampling Techniques ........................................................................................... 27 4.12.
4.12.1. Gillnets .................................................................................................................. 27
4.12.2. Electrofishing ........................................................................................................ 27
4.12.3. Angling ................................................................................................................. 29
4.12.4. Trot Lines .............................................................................................................. 29
4.12.5. Minnow Traps ....................................................................................................... 30
4.12.6. Snorkel Surveys .................................................................................................... 30
4.12.7. Fyke/Hoop Nets .................................................................................................... 31
4.12.8. Hoop Traps............................................................................................................ 31
4.12.9. Beach Seines ......................................................................................................... 31
4.12.10. Out-Migrant Traps ........................................................................................... 32
4.12.11. Fishwheels ....................................................................................................... 32
4.12.12. Fish Handling .................................................................................................. 33
4.12.13. Remote Fish Telemetry ................................................................................... 33
Results ................................................................................................................................... 36 5.
Objective 1: Fish Distribution, Relative Abundance, and Habitat Associations ......... 36 5.1.
5.1.1. Task A: Fish Distribution...................................................................................... 36
5.1.2. Task B: Relative Abundance ................................................................................ 42
5.1.3. Task C: Habitat Associations ................................................................................ 51
Objective 2: Seasonal Movements ............................................................................... 57 5.2.
5.2.1. Task A: Document the timing of downstream movement and catch for all fish
species using out-migrant traps. ............................................................................ 57
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii February 2014 Draft
5.2.2. Task B: Describe seasonal movements using biotelemetry .................................. 61
Objective 3: Early Life History ................................................................................... 69 5.3.
Objective 4: Document winter movements and timing and location of spawning for 5.4.
burbot, humpback whitefish, and round whitefish. ...................................................... 70
Objective 5: Characterize the seasonal size/ life stage structure, growth, and condition 5.5.
of juvenile anadromous and resident fish by habitat type. ........................................... 71
5.5.1. Growth by Habitat Type ....................................................................................... 71
5.5.2. Condition Factor by Habitat Type ........................................................................ 71
Objective 6: Document the seasonal distribution, relative abundance, and habitat 5.6.
associations of invasive species (northern pike). ......................................................... 72
Objective 7: Collect tissue samples from juvenile salmon and all resident and non-5.7.
salmon anadromous fish. .............................................................................................. 73
Discussion ............................................................................................................................. 73 6.
Objective 4: Document winter movements and timing and location of spawning for 6.4.
burbot, humpback whitefish, and round whitefish. ...................................................... 78
Completing the Study .......................................................................................................... 81 7.
Literature Cited ................................................................................................................... 82 8.
Tables .................................................................................................................................... 85 9.
Figures ................................................................................................................................ 135 10.
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iv February 2014 Draft
LIST OF TABLES
Table 2-1. Proposed methods by objective, task, species, and life stage. .................................... 85
Table 4.1-1 Salmon early life history sampling effort, 2013. ....................................................... 88
Table 4.1-2. Tributaries sampling effort for fish distribution in the Middle River above Devils
Canyon by geomorphic reach, 2013. ............................................................................................ 89
Table 4.1-3. Habitat types and number of sites sampled for distribution and relative abundance
sampling in the Middle River, 2013. ............................................................................................ 90
Table 4.1-4. Habitat types sampled for fish distribution in the Lower River by transect and reach
in 2013. ......................................................................................................................................... 91
Table 4.1-5. Antenna orientation for fixed-station receiver locations in the Middle and
LowerSusitna River, 2013. ........................................................................................................... 92
Table 4.1-6. Habitat types sampled during 2012/13 winter pilot study. ....................................... 93
Table 4.2-1. Monitoring efficiency (percent operational) of LGL operated fixed-station receivers
in the Susitna River drainage in 2013, by week............................................................................ 94
Table 4.2-2. Summary of aerial surveys of radio-tagged fish in the Upper Susitna River, 2013. 95
Table 4.5-1. Summary of PIT tagging effort in the Middle and Lower River Study Area, 2013. 96
Table 4.5-2. Summary of fishes radio-tagged in the Middle and Lower River Study Area, 2013.
....................................................................................................................................................... 97
Table 4.5-3. Summary of radio-tagging effort by target species, 2013. ....................................... 97
Table 4.8-1. Summary of size-at-life stage index used to classify Susitna River species, 2013. . 98
Table 4.8-2. Summary of fish with length and weight measurements collected in the Upper,
Middle and, Lower Susitna River by hydrologic segment, 2013. ................................................ 99
Table 4.8-3. Summary of PIT tagging efforts and recaptures for the Susitna River, 2013. ....... 100
Table 4.8-4. Fish sample size used in condition factor assessment for the Middle and Lower
Susitna River. .............................................................................................................................. 101
Table 4.10-1. Summary of Fish Distribution and Abundance tissue collection for genetic baseline
development, 2013. ..................................................................................................................... 102
Table 4.11-1 Summary of fish collection for gut sampling, 2013. ............................................. 103
Table 5.1-1. Summary of fish distribution by Geomorphic Reach the in Middle and Lower
Susitna River, 2013. .................................................................................................................... 104
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page v February 2014 Draft
Table 5.1-2. Middle Susitna fish observations, 2013.................................................................. 105
Table 5.1-3. Lower Susitna River fish observations, 2013 ......................................................... 106
Table 5.1-4. Total fish count by gear type for three seasonal fish distribution and abundance
sampling events in Middle River Focus Areas, 2013. ................................................................ 107
Table 5.1-5. Total fish count by gear type during three seasonal fish distribution and abundance
sampling events in the Middle River outside of Focus Areas, 2013. ......................................... 108
Table 5.1-6. Total fish count by gear type during three seasonal fish distribution and abundance
sampling events in the Lower River, 2103. ................................................................................ 109
Table 5.2-1. Middle and Lower River rotary screw trap catch at Indian River, Susitna River at
Curry Station, Susitna River at Talkeetna Station, and Montana Creek, 2013. .......................... 110
Table 5.2-2. Smolt to parr ratios for juvenile salmon caught in Middle and Lower River rotary
screw traps, 2013. ....................................................................................................................... 110
Table 5.2-3. Number of fish in the Middle and Lower Susitna River implanted with PIT tags in
2013............................................................................................................................................. 111
Table 5.2-4. Summary of PIT tag detections by species at the four stationary antenna arrays in
the Middle and Lower Susitna River study area, 2013. .............................................................. 112
Table 5.2-5. Juvenile Chinook salmon movement between macrohabitat types in the Middle and
Lower River in 2013 ................................................................................................................... 113
Table 5.2-6. Juvenile coho salmon movement between macrohabitat types in the Middle and
Lower River in 2013.. ................................................................................................................. 114
Table 5.3-1. Total count of juvenile anadromous and resident fish captured during Early Life
History sampling in the Middle and Lower Susitna River. ........................................................ 115
Table 5.3-2. Number of juvenile salmon fry (fork length <50mm) observed during Early Life
History Sampling in the Middle and Lower Susitna River.. ....................................................... 116
Table 5.3-3. Average fork length of juvenile salmon fry (fork length <50mm) caught during
Early Life History sampling in the Middle and Lower Susitna River. ....................................... 117
Table 5.5-1. PIT tag recaptures for pilot species fish used for growth assessment in the Middle
and Lower River, 2013. .............................................................................................................. 118
Table 5.5-2. Specific growth rates of juvenile Chinook salmon in the Middle and Lower River,
2013. Only fish with a minimum of eight days duration between recapture events were used for
growth assessment. ..................................................................................................................... 119
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vi February 2014 Draft
Table 5.5-3. Condition factors for juvenile Chinook salmon captured in the Middle and Lower
River, 2013. ................................................................................................................................. 120
Table 5.5-4. Condition factors for Arctic grayling captured in the Middle and Lower River,
2013............................................................................................................................................. 121
Table 5.6-1. Northern pike habitat associations by life stage, 2013. .......................................... 134
Table 5.6-2 Angling CPUE for northern pike in Lower River geomorphic reach-4 during fish
distribution and abundance sampling, 2013. ............................................................................... 134
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vii February 2014 Draft
LIST OF FIGURES
Figure 3-1. Upper Susitna River fish distribution and abundance study area. ........................... 135
Figure 4.1-1. Spring early life history (ELH) sampling locations in the Middle and Lower Susitna
River, 2013 .................................................................................................................................. 136
Figure 4.1-2. Fish distribution and abundance sampling transects in the Lower Susitna River,
2013............................................................................................................................................. 137
Figure 4.1-3. Outmigrant trap, PIT tag interrogation system, and radio fixed receiver locations in
the Middle Susitna River, 2013 1) .............................................................................................. 138
Figure 4.2-1. Summary of PIT tag interrogation system operation in the Middle and Lower
Susitna River, 2013. .................................................................................................................... 139
Figure 4.2-2. Rotary screw trap operation in the Middle and Lower Susitna River, 2013. ........ 140
Figure 4.8-1. Condition factor of juvenile Chinook salmon (top) and Arctic grayling (bottom) as
a function of length, 2013. .......................................................................................................... 141
Figure 5.2-1. Juvenile salmon catch by life stage at the Indian River rotary screw trap (PRM
142.1), 2013. ............................................................................................................................... 142
Figure 5.2-2. Juvenile salmon catch by life stage at the Susitna River at Curry Station rotary
screw trap PRM 124), 2013. ....................................................................................................... 143
Figure 5.2-3. Juvenile salmon catch by life stage at the Susitna River at Talkeetna Station rotary
screw trap (PRM 106.9), 2013. ................................................................................................... 144
Figure 5.2-4. Juvenile salmon catch by life stage at the Montana Creek rotary screw trap (PRM
80.8), 2013. ................................................................................................................................. 145
Figure 5.2-5. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by
life stage at the Indian River rotary screw trap, 2013. ................................................................ 146
Figure 5.2-6. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by
life stage at the Susitna River at Curry Station rotary screw trap, 2013. .................................... 146
Figure 5.2-7. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by
life stage at the Susitna River at Talkeetna Station rotary screw trap, 2013. ............................. 147
Figure 5.2-8. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by
life stage at the Montana Creek rotary screw trap, 2013. ........................................................... 147
Figure 5.3-1. Length frequency of juvenile salmon in the Middle and Lower Susitna River during
Early Life History sampling (April 29-June 29), 2013 ............................................................... 148
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page viii February 2014 Draft
Figure 5.5-1. Regression of juvenile chinook salmon SGRs over the tag implant date (top) and
fish implant length (bottom) in the Middle and Lower Susitna River; 2013. ............................. 149
Figure 5.5-2. Boxplots of specific growth rates for 13 juvenile Chinook salmon plotted by habitat
type for the Middle and Lower River, 2013. .............................................................................. 150
Figure 5.5-3. Boxplots of condition factors for juvenile Chinook salmon plotted by location for
the Middle / Lower River, 2013. ................................................................................................ 150
Figure 5.5-4. Boxplots of condition factors for Arctic grayling plotted by habitat type for the
Middle / Lower River, 2013........................................................................................................ 151
APPENDICES
Appendix A: Sampling Site Maps
Appendix B: Distribution of Fish Radio-Tagged in the Middle and Lower Susitna River, 2013
Appendix C: Winter Sampling Report
Appendix D: Fish Seasonal Distribution Tables
Appendix E: Relative Abundance Tables
Appendix F: Habitat Association Tables
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ix February 2014 Draft
LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
ADF&G Alaska Department of Fish and Game
AEA Alaska Energy Authority
AWC Anadromous Waters Catalog
BIC Bar Island Complex
CIRWG Cook Inlet Regional Working Group
CPUE catch per unit effort
ELH early life history
FA Focus Area
FDA Fish Distribution and Abundance
FERC Federal Energy Regulatory Commission
FL fork length
HSC habitat suitability criteria
ILP Integrated Licensing Process
IP Implementation Plan
ISR Initial Study Report
LR Lower River
MC Main Channel
MR Middle River
NTU nephelometric turbidity unit
PIT passive integrated transponder
PRM Project River Mile
Project Susitna-Watana Hydroelectric Project
RP river productivity
RSP Revised Study Plan
RST rotary screw traps
Rt-VW radio tagging
SANPCC Southcentral Alaska Northern Pike Control Committee
SC Side Channel
SCC Side Channel Complex
SPD study plan determination
TWG Technical Workgroup
USR Updated Study Report
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page x February 2014 Draft
EXECUTIVE SUMMARY
Study of Fish Distribution and Abundance in the Middle and Lower Susitna River (9.6)
Purpose The goal of this study is to characterize the current distribution, relative
abundance, run timing, and life history of resident and non-salmon
anadromous fish species as well as freshwater rearing life stages of
anadromous salmonids in the Middle and Lower Susitna River. Seven
specific objectives have been developed for this study and include multiple
tasks. Data collected as part of this study will be used to provide a baseline
characterization of fish assemblages in the Susitna River, to identify and
evaluate potential Project-induced effects on fish assemblages, and inform
development of any necessary protection, mitigation, and enhancement
measures.
Status Data collection is complete for the first year of this multiyear study. Initial
database quality assurance and quality control was completed to compile
preliminary summary statistics and preliminary data analysis for the Initial
Study Report. Database quality assurance and quality control, data analysis,
and coordination with interdependent studies are ongoing iterative processes.
A second study year of data collection is planned.
Study
Components Major study components include the following seven objectives:
• Describe the seasonal distribution, relative abundance, and fish habitat
associations of juvenile anadromous salmonids, non-salmonid
anadromous fishes and resident fishes.
• Describe seasonal movements of juvenile salmonids and selected fish
species such as rainbow trout, Dolly Varden, humpback whitefish,
round whitefish, northern pike, Arctic lamprey, Arctic grayling, and
burbot, with emphasis on identifying foraging, spawning and
overwintering habitats within the mainstem of the Susitna River.
• Describe early life history, timing, and movements of anadromous
salmonids.
• Document winter movements and timing and location of spawning for
burbot, humpback whitefish, and round whitefish.
• Document the seasonal age class structure, growth, and condition of
juvenile anadromous and resident fish by habitat type.
• Document the seasonal distribution, relative abundance, and habitat
associations of invasive species (northern pike).
• Collect tissue samples from juvenile salmon and opportunistically
from all resident and non-salmon anadromous fish to support the Fish
Genetic Baseline Study (Study 9.14).
2013 Variances
AEA implemented the methods as described in the Study Plan with the
exception of the following variances. The significance of these variances is
discussed within the ISR.
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page xi February 2014 Draft
• adjustments to Focus Area locations (Section 4.1.7.1);
• adjustments to rotary screw trap, PIT array, radio telemetry fixed
receiver, winter sampling, early life history sampling, and fish
distribution and abundance sampling locations (Section 4.1.7);
• adjustments to the number of fixed receiver and winter sampling
locations(Section 4.1.7);adjustments to the timing of fish distribution
and sampling efforts(Section 4.2.1);grouping select Middle and Lower
River macrohabitat classifications (Sections 4.1.7.2 and 4.4.4.3);
• adjustments to sample unit lengths (Section 4.4.4.1);
• adjustments to gear type applications (e.g., numbers of passes, soak
times; Section 4.4.4.2);
• refinements to estimating the detection efficiency of PIT tag
interrogation systems (Section 4.5.3.1);
• adjustments to the timing of radio-tag implementation and aerial
survey methods for tracking resident fish (Sections 4.5.3.2 and
4.5.3.3; and
• utilizing size instead of age to evaluate habitat associations of juvenile
anadromous and resident fish (Section 4.8.1).
Steps to
Complete the
Study
[As explained in the cover letter to this draft ISR, AEA’s plan for completing
this study will be included in the final ISR filed with FERC on June 3, 2014.]
Highlighted
Results and
Achievements
In 2013, sixteen species were captured in the Middle and Lower Susitna
River. In the Middle River, over 43,500 fish were observed during three
seasonal surveys at over 160 sites covering 4 tributaries above Devils Canyon
and approximately 84.7 miles of the Susitna River. Juvenile coho salmon,
threespine stickleback, adult pink salmon, and sculpin were the most
abundant species. Both the total number of species and the relative
abundance of all species except Arctic grayling and Dolly Varden were
notably higher downstream of Devils Canyon. In the Lower River, over
11,900 fish were observed during three seasonal surveys at 44 sites
representing 70.1 miles of the Lower Susitna River. Threespine stickleback
were the most abundant species comprising over 35 percent of all fish
observations. Northern pike were not observed in the Middle River.
Northern pike were observed only in Geomorphic Reach LR-4 of the Lower
River (PRM 32.3-PRM 44.6). Over 5,600 fish were tagged for biotelemetry
studies of fish movement in both the Middle and Lower River. Sampling in
2013 met all first-year study goals and objectives.
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 February 2014 Draft
INTRODUCTION 1.
On December 14, 2012, Alaska Energy Authority (AEA) filed its Revised Study Plan (RSP) with
the Federal Energy Regulatory Commission (FERC or Commission) for the Susitna-Watana
Hydroelectric Project (FERC Project No. 14241), which included 58 individual study plans
(AEA 2012). Included within the RSP was the Study of Study of Fish Distribution and
Abundance in the Middle and Lower Susitna River, Section 9.6. RSP Section 9.6 focuses on
describing the current fish assemblage including spatial and temporal distribution, and relative
abundance by species and life stage in the Susitna River downstream of the proposed Watana
Dam.
On February 1, 2013, FERC staff issued its study plan determination (February 1 SPD) for 44 of
the 58 studies, approving 31 studies as filed and 13 with modifications. FERC requested
additional information before issuing a SPD on the remaining studies. The Susitna River Fish
Distribution and Abundance Implementation Plan (FDA IP) was filed with FERC on January 31,
2013 and was subsequently presented and discussed during a Technical Work Group (TWG)
meeting on February 14, 2013. With consideration of the comments and suggestions received
from licensing participants, the FDA IP was filed with FERC on March 1, 2013. On April 1,
2013 FERC issued its study determination (April 1 SPD) for the remaining 14 studies; approving
1 study as filed and 13 with modifications. RSP Section 9.6 was one of the 13 approved with
modifications. In its April 1 SPD, FERC recommended the following:
Middle and Lower River Mainstem Sample Unit Length
- We recommend that sampling unit lengths for all main channel and side channel habitat
units be equal to 20 times the wetted channel width of the habitat unit, the entire length of the
habitat unit, or 500 meters, whichever is less.
- We recommend that sampling unit lengths for all slough macrohabitats encompass the
entire length of the slough, a distance equal to 20 times the wetted channel width of the
slough, or 200 meters, whichever is less. We also recommend that slough sampling be
initiated at the downstream end of the slough.
- We recommend that, to the extent possible based on site-specific field conditions, AEA
sample all main channel and side channel macrohabitat units with boat electrofishing
methods.
- We recommend that AEA’s proposed tributary mouth sampling unit lengths include the
backwater area within the tributary, if present, and extend a distance 200 meters
downstream of the tributary mouth/confluence with the mainstem.
Timing of Sampling
- We recommend that the proposed summer sampling events be conducted in mid-July, and
again in either late August or early September. We recommend that the proposed autumn
sampling occur in late September to early October.
INITIAL STUDY REPORT STUDY OF FISH DISTRIBUTION AND ABUNDANCE IN THE
MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 February 2014 Draft
Catch Per Unit Effort from Electrofishing Macrohabitats
- We recommend that calculation of CPUE from electrofishing data be based only on the first
pass, as requested by NMFS and FWS.
- We recommend that minnow traps be soaked for 24 hours and placed within locations most
likely to capture fish (e.g., low-velocity habitat in close proximity to cover).
PIT Tag Antenna Array at Whiskers Creek
- We recommend that, if feasible given site-specific conditions, AEA locate the PIT tag array
downstream of the confluence of the side slough and Whiskers Creek, or at the mouth of
Whiskers Creek. Should these locations not be feasible for deployment, AEA should consult
with the TWG and select an appropriate location for the PIT tag array at Whiskers Slough.
Radio Tagging of Resident Fish
- To the extent possible given the constraints of field sampling conditions, we recommend
that AEA target its fish sampling to meet the following specific objectives: (1) a minimum of
10 tags per species be allocated for tagging adult grayling and rainbow trout of sufficient
size for spawning at tributary mouths during the spring sampling event; (2) a minimum of 10
tags be allocated for tagging adult Dolly Varden of sufficient size for spawning at tributary
mouths during a late summer or early fall sampling event; (3) a minimum of 10 tags be
allocated for tagging adult whitefish prior to spawning in early September; and (4) a
minimum of 10 tags be allocated for tagging burbot in the early fall prior to fall or winter
spawning migrations.
In accordance with the April 1 SPD, AEA has adopted the FERC requested modifications in the
FDA IP. Following the first study season, FERC’s regulations for the Integrated Licensing
Process (ILP) require AEA to “prepare and file with the Commission an initial study report
describing its overall progress in implementing the study plan and schedule and the data
collected, including an explanation of any variance from the study plan and schedule.” (18 CFR
5.15(c)(1)). This Initial Study Report (ISR) on Fish Distribution and Abundance Middle and
Lower Susitna River has been prepared in accordance with FERC’s ILP regulations and details
AEA’s status in implementing the study, as set forth in the RSP, FDA IP, and as modified by
FERC’s April 1 SPD (collectively referred to herein as the “Study Plan”)."
STUDY OBJECTIVES 2.
The overarching goal of this study is to characterize the current distributions, relative
abundances, run timings, and life histories of all resident and non-salmon anadromous species
encountered including, but not limited to Dolly Varden, eulachon, humpback whitefish, round
whitefish, arctic grayling, northern pike, burbot, and Arctic lamprey, as well as freshwater
rearing life stages of anadromous salmonids (fry and juveniles) in the Middle and Lower Susitna
River. Specific objectives include the following (Table 2-1):
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1) Describe the seasonal distribution, relative abundance (as determined by CPUE, fish
density, and counts) and fish habitat associations of juvenile anadromous salmonids, non-
salmonid anadromous fishes and resident fishes.
2) Describe seasonal movements of juvenile salmonids and selected fish species such as
rainbow trout, Dolly Varden, humpback whitefish, round whitefish, northern pike, Arctic
lamprey, Arctic grayling, and burbot, with emphasis on identifying foraging, spawning
and overwintering habitats within the mainstem of the Susitna River.
a. Document the timing of downstream movement and catch using out-migrant
traps.
b. Describe seasonal movements using biotelemetry (passive integrated transponder
[PIT] and radio-tags).
3) Describe early life history, timing, and movements of anadromous salmonids.
a. Describe emergence timing of salmonids.
b. Determine movement patterns and timing of juvenile salmonids from spawning to
rearing habitats.
c. Determine juvenile salmonid diurnal behavior by season.
d. Collect baseline data to support the Stranding and Trapping Study.
4) Document winter movements and timing and location of spawning for burbot, humpback
whitefish, and round whitefish.
5) Document the seasonal age class structure, growth, and condition of juvenile anadromous
and resident fish by habitat type.
6) Document the seasonal distribution, relative abundance, and habitat associations of
invasive species (northern pike).
7) Collect tissue samples from juvenile salmon and opportunistically from all resident and
non-salmon anadromous fish to support the Fish Genetic Baseline Study (Study 9.14).
STUDY AREA 3.
The Middle and Lower study area (Figure 3-1) encompasses the Susitna River from PRM 32.3
immediately upstream of the confluence with the Yentna River upstream to the proposed Watana
Dam site (PRM 187.1). The Middle and Lower fish distribution and abundance study area
includes the entire Middle River Segment and the majority of the Lower River Segment.
The Middle River Segment includes the mainstem Susitna River from the proposed Watana Dam
Site (PRM 187.1) downstream to the confluence of the Talkeetna and Chulitna Rivers (Three
Rivers Confluence) at PRM 102.4. This segment is subdivided in eight distinct geomorphic reaches.
The Middle River Segment contains ten Focus Area (FA) study sites which are intended to serve as
specific geographic areas of the river that will be the subject of intensive investigation by multiple
resource disciplines.
The Lower River Segment extends from the Three Rivers Confluence to Cook Inlet. The study
area within the Lower River consists of approximately 70 miles of river between the Three
Rivers Confluence and Yentna River and is further subdivided into four geomorphic reaches
(Figure 3-1).
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METHODS 4.
This study employed a variety of field methods to build on the existing information related to the
distribution and abundance of fish species in the Middle and Lower Susitna River consistent with
the Study Plan except for specific variances as described below. The following sections provide
brief descriptions of study site selection, sampling frequency, the approach, and suite of methods
that were used to accomplish each objective of this study. This study was initiated during the
winter of 2012/13 and will continue in the next study year.
Fish Distribution and Abundance Implementation Plan
A final sampling scheme was developed as part of the detailed Fish Distribution and Abundance
Implementation Plan (IP) which was approved by FERC, with modifications, on April 1, 2013.
The final IP consists of (1) a summary of relevant fisheries studies in the Susitna River, (2) an
overview of the life-history needs for fish species known to occur in the Susitna River, (3) a
review of the preliminary results of habitat characterization and mapping efforts in 2012 (Study
9.9), (4) a description of site selection and sampling protocols, (5) development of field data
collection forms, (6) development of database templates that complied with 2012 AEA QA/QC
procedures, and (7) FERC’s requested modifications included in the April 1 SPD. The
Implementation Plan includes the level of detail sufficient to instruct field crews in data
collection efforts. In addition, the plan includes protocols and a guide to the decision making
process in the form of a chart or decision tree that was used in the field, specific sampling
locations, details about the choice and use of sampling techniques and apparatuses, and a list of
field equipment needed. The Implementation Plan addresses the random selection of sampling
locations and helps to ensure that fish collection efforts occurred in a consistent and repeatable
fashion across field crews and river segments. Sampling methods by objective are presented
below and in Table 2-1. Brief descriptions of each sampling technique are provided in Section
4.12.
Study Site Selection 4.1.
Study sites in the Middle and Lower Susitna River covered multiple objectives using various
techniques and technologies over a 155-mile study reach. The intensity of sampling effort also varied
based on proximity to the proposed Project, habitat availability, and historic habitat utilization by
anadromous and resident fishes. Field sampling sites included those for: the study of salmon early
life history, the study of fish distribution and abundance, rotary screw traps, PIT tag interrogation
sites, fixed radio telemetry stations, and winter study sites. AEA implemented the site-selection
methods as described in the Study Plan with the exception of the variances explained in Section
4.1.7.
4.1.1. Early Life History Sites
Early life history (ELH) sampling took place every two weeks between ice break-up and July 1
in six Middle River Focus Areas downstream of Devils Canyon, a tributary and headwater lake
upstream of Devils Canyon, and select Lower River tributaries and sloughs (Table 4.1-1).
During ELH sampling events, study locations in selected Focus Areas included three 40-meter
long sampling units immediately downstream of a documented Chinook, chum, or coho salmon
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spawning area (these were tributary mouths or side sloughs at some Focus Area locations) and
three 40-meter long rearing habitat sampling units. Additional sampling occurred in Fog Creek,
a lake in the Fog Creek basin, and in select spawning and rearing habitats (tributaries, tributary
mouths, and sloughs) in the Lower River (Table 4.1-1). Sampling unit lengths in tributaries
above Devils Canyon were 100 m (328 ft), in the Lower River sampling effort included three, 40
m (131 ft) segments within 200 m (656 ft) sampling reaches.
4.1.2. Fish Distribution and Abundance Sites
4.1.2.1. Middle River Tributaries above Devils Canyon
Tributaries selected for fish distribution and abundance sampling upstream of Devils Canyon
(PRM 153.9 to169.6) and below the proposed Watana Dam Site (PRM 187.1) included all
known Chinook salmon-bearing tributaries and other tributaries that were not listed in ADF&G’s
Anadromous Waters Catalog (AWC; ADF&G 2012). Initially seven tributary streams were
selected for sampling based on: AWC catalog listings, drainage basin, historical and 2012
sampling efforts, and the potential for impact/inundation from the proposed Project (Table 4.1-
2). Prior to field sampling these tributaries were screened for accessibility based on stream
gradient, channel morphology (i.e., confined canyon), tributary mesohabitat type (rapid and
cascade) and physical access. The screening resulted in three tributaries that were inaccessible
(Unnamed Tributary 184, Devil Creek, and Cheechako Creek) and four tributaries where access
was unknown (Tsusena Creek, Fog Creek, Fog Creek Tributary, and Chinook Creek).
A direct sampling methodology was implemented on the four tributary streams with unknown
access (Table 4.1-2). For these four streams, an average effort of two, 100 m (328 ft) sites were
sampled over a one to two day period. The goal of sampling was to distribute effort over the
accessible study area in several locations that represented geomorphic reaches or habitat features.
Where aerial still or video imagery was available, proposed sample locations were identified and
reviewed prior to field activity. Habitat observed from the remote imagery at identified locations
was documented and field teams attempted to sample pre-identified tributary mesohabitat units
(pool, riffle, glide, etc.). Where imagery was unavailable, sampling location and effort was
determined during the first sampling effort for each tributary.
4.1.2.2. Mainstem Middle River
The Middle River habitat mapping effort completed in early 2013 provided delineation of habitat
units in the main channel and off-channel areas of the Susitna River (ISR Study 9.9). A
hierarchical and nested classification system developed specifically for the Susitna River with
input from the Fish and Aquatics Technical Working Group (TWG) was used to classify habitat.
A summary of the Middle River habitat mapping results can be found in Section 4.4 of the
Implementation Plan or in the Middle Susitna River Segment Remote Line Habitat Mapping
Technical Memorandum (AEA 2013). The following habitat strata were used for Middle River
Fish Distribution and Abundance sampling: (1) main channel, (2) side channel, (3) backwater,
(4) side slough, (5) side slough with beaver complex, (6) upland slough, (7) upland slough with
beaver complex, (8) tributary and (9) tributary mouth. Furthermore, each time sampling
occurred at a slough site the slough mouth was inspected for backwater influence from the main
channel of the Susitna and selected for sampling if an appropriate backwater unit was present.
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Clearwater plumes were present at several tributary mouths and upland slough confluences and
provided habitat conditions distinct from the surrounding habitat unit. Fish sampling targeted
clearwater plumes as distinct sampling units when encountered.
Main channel habitat varied by geomorphic reach within the Middle River and generally
increased in complexity (islands and side channels became more frequent) from upstream to
downstream locations. The habitats associated with the confluence of tributaries with the main
channel river included tributary mouths and clearwater plumes; however not all tributaries that
entered the Middle River had tributary mouth or clearwater plume habitats. Small tributaries
where the vegetation line was close to the mainstem did not fan out and create the areas
classified as tributary mouth habitat. In addition, small tributaries or tributaries that flowed into
fast moving or turbulent sections of the mainstem did not produce clearwater plume habitats.
Off-channel habitat was assigned to three habitat types observed: upland sloughs, side sloughs,
and backwaters. In addition to other unique characteristic features, sloughs were differentiated
from backwater habitat by clear water. Beaver complexes were consistently associated with
slough habitats and as such were not categorized as a habitat type but were noted as a
characteristic of slough habitat units. Beaver dams were rarely present in side slough habitat,
and slightly more prevalent in upland sloughs.
The length data associated with the habitat unit delineation line mapping facilitated the use of a
Generalized Random Tessellation Stratified (GRTS) sampling approach in the Middle River.
The GRTS design produced a spatially balanced random sample with design-based variance
estimators. In addition, the GRTS sampling method provided an over-sample of sample sites to
accommodate field implementation issues (e.g., a location was not accessible or was too deep to
be sampled and was skipped). Each unit to be sampled was placed in random order so that the
random order was preserved if a sample needed to be skipped.
In the Middle River, the GRTS design was used to select study sites based on a habitat stratified
sampling scheme nested within Middle River geomorphic reaches MR-1, MR-2, MR-5, MR-6,
MR-7, and MR-8. It is important to note that not all habitat types were found within each
geomorphic reach. Sampling was not safe or feasible in the geomorphic reaches in Devils
Canyon (MR-3 and MR-4).
Within each geomorphic reach sampled, two strata were formed: 1) the combined Focus Areas
within the reach; and 2) the remainder of the reach not in Focus Areas. Within each of these
strata, the total length of habitat in each habitat type (main channel, split main channel, multiple
split main channel, side channel, upland slough with beaver complex, upland slough without
beaver complex, side slough with beaver complex, and side slough without beaver complex) was
represented by line segments from the remote habitat mapping in 2012. For selection of
sampling units, these line segments for each habitat type were partitioned into 200 m (656 ft) and
500 m (1640 ft) units for main and side channels. In contrast, tributaries (mouth to upper extent),
tributary mouths, clearwater plumes, and backwaters, were selected as GRTS samples as point
locations. For both line segment and point sampling, three sampling units were selected for each
habitat type within each stratum (Focus Areas and non-Focus Areas within each geomorphic
reach). When three or fewer sampling units existed within the sample stratum, all available units
were selected for sampling. All of the selected sample sites within Focus Areas were sampled
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for relative abundance. Outside of Focus Areas, all selected sites were sampled for fish
distribution and one of the selected sites for each available habitat type was also sampled for
relative abundance.
A GRTS model was used to randomly select fish sampling segments from those in the
population. Table 4.1-3 presents the GRTS selected and field attained sample units by stratum.
A total of 162 sites were sampled from the 177 targeted sites in the Middle River including 76
sites sampled for relative abundance within Focus Areas, and 86 sites outside of Focus Areas.
The selected sample sites are displayed by geomorphic reach in Figures 4.1-2 through 4.1-7.
The IP identified sampling site targets based on sampling unit lengths of 40 m (131 ft) for off-
channel habitats and 240 m (787 ft) for main channel habitats (IP Section 5.3). When AEA
adopted the SPD recommendations for increased sampling unit lengths, these longer sampling
units reduced the number of replicates for some rare sampling strata (e.g, side channels above
Devils Canyon). Thus, when GRTS was rerun the overall number of sampling targets was
reduced by four (Table 4.1-3). Sample unit lengths for off-channel, Middle River tributary, and
special main channel sampling units (backwater, clearwater plume) were 20x the wetted channel
width or 200 m (656 ft), whichever was less. Sampling unit length for main and side channel
sampling units where boat electrofishing and drift gill nets were employed was 20x the wetted
channel width, 500 m (1640 ft), or the complete unit, whichever was less. Boat electrofishing
was employed in main channel habitats whenever feasible. When sample methods other than
boat electrofishing were also feasible, the sample length for other gear types was 200 m (656 ft).
4.1.2.3. Mainstem Lower River
Fish distribution and relative abundance sampling in the mainstem Lower Susitna River was
conducted from PRM 32.3 to 102.4. This survey area included Geomorphic Reaches LR-1
(PRM 102.4-87.9), LR-2 (PRM 87.9-65.6), LR-3 (PRM 65.6-44.6), and LR-4 (PRM 44.6-32.3).
Due to channel morphology in the Lower River and corresponding limitations of the geomorphic
based habitat mapping therein, a systematic random transect approach was adopted whereby fish
sampling sites were selected within habitat units encountered along transects. Using a random
start for the Lower River study area, ten equally spaced transects were located at 7.4-mile
intervals (Table 4.1-4). Across each transect, one habitat unit of each type encountered was
selected for sampling. Many transects spanned multiple habitat types (e.g., main channel, side
channel, upland slough, and side slough) because of the complex nature of the Lower River
(Figure 4.1-8). The IP (Table 5.4-1) estimated that the ten transects would contain a total of 44 1
habitats based on the available remote habitat information. Where multiple habitat units of the
same type occurred, units were randomized and one was selected for sampling.
Fish distribution and abundance sampling was conducted starting at the downstream end for a
distance equal to 20x the wetted channel width or 500 m (1640 ft), whichever was smaller for
main channel, side channel, side channel complex, and bar island complex habitats. Boat
electrofishing was employed in main channel habitats whenever feasible, though due to
1 Total habitats in IP Table 5.4-1 sum to 44, despite reported total of 42.
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restrictions around electroshocking adult salmonids, was not fully deployed (for the entire 500 m
site length) at most sites until the autumn sampling event. When boat electrofishing or drift
gillnetting was not feasible, a 200 m (656 ft) sampling unit was sampled with other techniques.
If the randomly selected habitat unit was totally inaccessible to field crews or dewatered during
the first sampling event, then a second randomly-selected habitat unit was sampled. Off-channel,
Lower River tributary, and special mainstem mesohabitat sampling units (e.g. backwaters,
clearwater plumes) were sampled at units equal to 20x the wetted channel width or 200 m,
whichever was less.
For the Lower River, Table 4.1-4 shows the habitat units sampled along each random transect.
One transect within each geomorphic reach was sampled for relative abundance, with the
remaining transects sampled for distribution only. The transect with the most habitat units was
selected for abundance sampling in each reach. A total of 44 habitats were sampled seasonally
along the 10 transects.
4.1.3. Rotary Screw Trap Sites
Final site selection for the Middle River rotary screw traps (RSTs) was determined using the
following criteria: 1) a suitable location downstream of documented adult or juvenile Chinook
salmon distribution; 2) land ownership, eliminating river reaches where landowners would not
allow access; 3) accessibility, rotary screw trap locations needed to be accessible by helicopter;
4) depth, a minimum depth of 1.25 m (4.1 ft) during low-flow periods; and 5) hydraulic
conditions, consistent laminar flow with velocities in the range of 0.6-2 m/s (2-6.6 ft/s). Site
reconnaissance included review of aerial videography from summer 2012, a pre-bank-ice-break-
up site visit to a short list of locations on May 24, 2013 and final pre-installation site visits on
June 7, 2013.
In the Middle River, trap locations included the Indian River (PRM 142.1) at its confluence with
the Susitna River, the mainstem Susitna River at Curry Station (PRM 124), and the mainstem
Susitna River at Talkeetna Station (PRM 106.9) (Figure 4.1-3). The Indian River was selected
because it is a primary tributary to the Middle River and is heavily used by Chinook and coho
salmon and a diversity of resident fish species (ADF&G 1984; HDR unpublished). In addition,
the lower Indian River near its confluence with the Susitna River has historically been a focus of
Middle River sampling efforts (ADF&G 1984). The two mainstem river sites were selected,
because they offered good hydraulic conditions for rotary screw trap operation and are located
downstream of important Middle River spawning tributaries including Portage Creek and the
Indian River. The site at Talkeetna Station has the added benefit of being associated with
historic data from outmigrant trapping efforts in the 1980s (Roth et al. 1986). In 1985, inclined
plane traps at Talkeetna Station had significantly higher catch rates on the west bank of the
Susitna River than on the east bank (Roth et al. 1986); thus, the rotary screw trap for the 2013
study was located in a similar position. Lastly, each of the three proposed Middle River trapping
locations were located in close proximity to other field efforts; this co-location of sites helped to
facilitate site accessibility, field logistics, safety, and effective trapping operations.
In the Lower River, an outmigrant trap was located in Montana Creek (PRM 80.8) near Tributary
River Mile 2.2. Montana Creek was selected because it is one of the major salmon-producing
tributaries in the Lower River study area and has a diverse resident fish assemblage.
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4.1.4. PIT Interrogation Antenna Sites
Final locations for PIT tag antenna arrays were determined using the following criteria: 1)
suitable location downstream of documented anadromous salmon spawning and rearing areas or
historic resident fish habitat; 2) land ownership, eliminating river reaches where landowners
would not allow access; 3) accessibility, PIT antenna materials had to be transported and
serviced by helicopter; 4) depth, a maximum depth of around 0.5 m (1.64 ft) was desired for
reasonable swim-over antenna performance; and 5) hydraulic conditions, lower velocity areas
were selected where installation and maintenance could be done safely under a range of flow
conditions. Three stationary PIT tag interrogation sites were installed in the Middle River
Segment: Indian River approximately 0.1 mi upstream from its confluence with the Susitna River
(PRM 142.1), Slough 8A (PRM 129), and Whiskers Slough downstream of the confluence of the
side slough and Whiskers Creek (PRM 105) (Figure 4.1-3). These sites were selected based on
historic fish use data and to co-locate PIT arrays with Focus Areas and radio-telemetry arrays.
The Indian River is a primary tributary of the Middle River and is heavily used by both Chinook
and coho salmon and a diversity of resident fish species targeted for PIT tagging (ADF&G
1984a; HDR unpublished). The Indian River is a large, dynamic tributary and main channel
widths and hydraulic conditions in the main channel exceeded the capabilities of half-duplex PIT
interrogation antenna length. This necessitated seasonal adjustments of antenna location
between a split-main channel location (river left channel approximately 100 m [328 ft] upsteam
of the mouth) and partial coverage of the main channel when the system could be safely
installed, maintained, and operated at a pool tailout approximately 90 m upstream of mouth. The
site location at Slough 8A was approximately 200 m (656 ft) upstream of the confluence with a
side channel. These side channel and side slough habitats historically supported high levels of
juvenile salmon and resident fish use. Whiskers Slough, between the confluence of Whiskers
Creek and the slough mouth, was selected for its proximity to spawning and juvenile rearing
habitat and it represents a location where resident fish were historically abundant. During the
1980s, the following target species were present in Whiskers Slough: juvenile Chinook salmon,
juvenile coho salmon, juvenile sockeye salmon, Arctic grayling, Arctic lamprey, burbot, Dolly
Varden, rainbow trout, humpback whitefish, and round whitefish (Schmidt et al. 1983).
In the Lower River, one stationary interrogation system was installed in Montana Creek (PRM
80.8) approximately 2.2 river miles upstream of the confluence with the Susitna. This location
was selected because Montana Creek is one of the major salmon-producing tributaries in the
Lower River study area and provides habitat for a diversity of resident species. The antenna was
co-located with a rotary screw trap on a parcel of State of Alaska land with foot access from the
Parks Highway after a thorough review of landownership, recreation pressure, vandalism risk,
and hydraulic conditions.
4.1.5. Fixed Radio Telemetry Sites
Fixed radio telemetry stations were installed at nine locations in the Lower and Middle Susitna
River (Table 4.1-5; Figure 4.1-10). The primary objective of four stations was to track the
movements of radio-tagged fish in the mainstem of the Susitna River (Lane Creek [PRM 117;
near the mouth of Lane Creek], Gateway [PRM 130; upstream of Curry], Powerline [PRM 146;
between Indian River and Portage Creek], and Devils Island [PRM 167; upstream of Devil
Creek). Two stations offered coverage of the mainstem of the Susitna as well as a tributary (4th
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of July Creek [PRM 134] and Indian River [PRM 142]). The station at Whiskers Creek (PRM
105) offered coverage of Whiskers Creek and slough and limited coverage of the mainstem
Susitna River. Montana Creek and Upper Indian River stations monitored movements in their
respective tributary exclusively. The spatial and temporal distribution of radio tags within each
river segment was determined by the sampling schedule of the Fish Distribution and Abundance
Study program and the availability of fish of each target species.
4.1.6. Winter Study Sites
In 2013, winter pilot studies were conducted at FA-104 (Whiskers Slough, PRM 104.8-106) and
FA-128 (Slough 8A, PRM 128.1-129.7) in the Middle River Focus Areas. These Focus Areas
were selected based on their accessibility from Talkeetna, the diversity of habitat types present,
and their documented use as spawning and rearing habitats for salmonids in the 1980s and 2012.
Whiskers Slough (FA-104) contains a diverse range of habitat, which is characteristic of the
braided, unconfined Geomorphic Reach MR-8 in the Middle River. FA-104 (Whiskers Slough)
was selected for study because its habitats supported juvenile and adult fish use and a range of
habitat modeling methods were used in side channel and side slough areas. FA-128 (Slough 8A)
consisted of side channel, side slough and tributary confluence habitat features that are
characteristic of the braided Geomorphic Reach MR-6 in the Middle River. Ice coverage was
variable and both study areas contained open-water leads and groundwater-influenced upwelling
areas. Site selection for the pilot study occurred in the field based on the availability of water
under ice to sample or the presence of open-water leads. Pilot holes were drilled with an ice
auger to determine whether sites were suitable for sampling. A variety of habitats were selected
for testing winter techniques including: tributary, tributary mouth, upland slough, side slough,
slough mouth, side channel, main channel and other off-channel habitats (Table 4.1-6).
4.1.7. Variances from Study Plan
4.1.7.1. Early Life History Sites
The Study Plan specified ELH sampling at six sites in each of five Middle River Focus Areas (IP
Section 5.5). However, with the addition of FA-113 (Oxbow I) following Implementation Plan
development, sampling took place at six sites in each of six Focus Areas (Table 5.1-1).
Furthermore, when AEA adopted the FERC recommendation of seasonal sampling in mid-July
and late August/early September and late September/early October in the Middle and Lower
River, additional ELH sampling locations were added in tributaries and lakes upstream of Devils
Canyon and the tributaries and sloughs in the Lower River to gather information on juvenile
salmon life history during the period from ice break-up to July 1. Expansion of Early Life
History sampling is anticipated to enhance AEA’s ability to meet the study objectives.
4.1.7.2. Fish Distribution and Abundance Sites
The lower reaches of tributaries of the Susitna River upstream of Devils Canyon are typified by
high-gradient, confined canyons, with dense vegetation. These conditions, particularly in the
smaller tributaries, limited helicopter access. Other factors that influenced sampling times or
locations included dangerous sampling conditions (high water, high wind, and icy conditions)
and dry target sites.
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The IP was filed before the tenth Focus Area was designated within the Middle River. The
Adjustments to Middle River Focus Areas Tech Memo filed in May 2013, placed the tenth Focus
Area in Geomorphic Reach MR-7 (AEA 2013b). This change added six sites to sampling targets
within Focus Areas for fish abundance sampling and moved one tributary mouth site previously
outside of a Focus Area in MR-7 into FA-113 (Oxbow I).
Land ownership and accessibility influenced fish sampling in discrete areas of the Middle River.
Access was not permitted for Middle River tributary and upland slough sites on Cook Inlet
Regional Working Group (CIRWG) and Alaska Railroad Corporation lands. CIRWG lands
included the entire non-navigable section of the Susitna River from the mouth of Portage Creek
(PRM 152.3) to the mouth of Devil Creek (PRM 164.8) and areas above ordinary high water
mark (OHWM) from the mouth of Devil Creek to the proposed dam site (PRM 187.1). The
main channel habitat within FA-151 (Portage Creek) was restricted; therefore the upstream end
of site FDA-151-48-MC1 was established approximately 200 m (656 ft) downstream of the
original site boundary. Similarly, sampling the entire clearwater plume habitat within FA-151
(Portage Creek) was limited due to land access restrictions. Therefore the upstream end of site
FDA-151-46-CWP was established approximately 100 m (328 ft) downstream of the original site
boundary. Alaska Railroad Corporation lands influenced site selection for Middle River
tributaries and upland slough sites along the river left (east) bank of the Susitna River between
PRM 107.7 and 140.0. In most cases, GRTS oversamples were used to replace sites on Alaska
Railroad Corporation lands. However one tributary and one upland slough site could not be
accessed or replaced and were not sampled (Table 4.1-3).
Prior to sampling in July, the target sites (177 GRTS sites, 10 Lower River mainstem transects
[IP Section 5.4]) and direct sample tributaries were visited and assessed for safety. Following
the reconnaissance visit, target GRTS sites deemed not conducive to sampling were replaced
consistent with GRTS protocol.
The SPD recommended that AEA sample mainstem habitats using separate strata for main
channel, split main channel and multi-split main channels. However, based on stakeholder
recommendations during the study plan development and ongoing discussions in the Fish and
Aquatic TWG meetings regarding the potential to extend an unbalanced effort in these habitats,
these three channel forms were sampled as a single strata designated as main channel. During
sampling, field crews noted macrohabitat type (e.g., main channel, split channel, or multi-split
main channel). This variance resulted in 30 fewer mainstem sites being sampled (Table 4.1-3).
This may have decreased the ability to evaluate the distribution, abundance and habitat
associations for rare species in mainstem habitats. However, “NMFS and FWS state that AEA’s
level 3 mainstem habitat classification results in too many habitat classes, limiting adequate
replication. NMFS and FWS state that AEA’s proposed level 4, split main channel and braided
channel habitat types are a geomorphic classification and do not provide habitat characteristics or
values that should be distinguished at the macrohabitat level” (FERC SPD April 1 , 2013). This
variance is not anticipated to impact AEA’s ability to meet the seasonal distribution component
of Objective 1; however, the degree to which fish relative abundance and habitat associations
vary among main channel habitat types will be further analyzed.
Sampling took place at 162 Middle River GRTS sites and 44 sites along 10 Lower River
mainstem transects for a total of 206 target sites (Tables 4.1-3 and 4.1-4). Additionally, 15
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locations were sampled in 4 direct sample tributaries above Devils Canyon (Table 4.1-2). The
15 GRTS sites that were not sampled or replaced with oversamples were located on Cook Inlet
Regional Working Group (CIRWG) or Alaska Railroad Corporation lands where access was not
permitted. Due to land ownership, Unnamed Tributary 184, Devil Creek, and Cheechako Creek
were not sampled and site locations within the sampled tributaries were limited to non CIRWG
lands. CIRWG lands between Portage Creek (PRM 152.3) and the proposed Watana Dam site
(PRM 187.1) include a corridor through Devils Canyon and along the Susitna River extending
several miles from both the right and left bank. Tributary sampling in this reach including:
Tsusena Creek, Fog Creek, a Fog Creek Tributary, and Chinook Creek, was limited to the
tributary reaches upstream of this boundary. This variance is not anticipated to impact AEA’s
ability to determine fish distribution, abundance, and habitat associations in the Middle River
below Devils Canyon and in the Lower River. However, in the Middle River above Portage
Creek, where access was most restricted in 2013; the impact of this variance is subject to future
land access and sampling results.
4.1.7.3. Rotary Screw Trap and PIT Interrogation Sites
The IP proposed that the Indian River downstream migrant trap would be located near TRM 1
(Section 5.7.1). After reconnaissance of the area, a location with better conditions for trap
installation and operation at the mouth of Indian River was selected. The IP proposed that the
Montana Creek trap would be located near the confluence of the Susitna (Section 5.7.1). Due to
land ownership, high recreation use, an elevated potential for vandalism, and the shallow,
braided character of the channel near its confluence with the Susitna, a location was selected on
State of Alaska lands approximately 2.2 tributary miles upstream from the confluence. The final
locations improved AEA’s ability to meet study objectives by improving trap performance and
reducing conflicts with other river users that could interfere with trap operation. Corresponding
stationary PIT tag interrogation sites (IP Section 5.6.5) were moved in coordination with the
rotary screw traps.
4.1.7.4. Radio Telemetry Fixed Receiver Sites
In Section 5.8.2.1 of the Implementation Plan, AEA proposed that nine fixed-station receivers be
operated in the Middle River in coordination with the Salmon Escapement Study (Study 9.7)
including: Lane Creek Station (PRM 116.7), Gateway (PRM 130.1), Fourth of July Creek (PRM
134.3), Indian River (PRM 142.1), Slough 21 (PRM 144), Portage Creek (PRM 152.3),
Cheechako Station (PRM 155.9), the Chinook Creek confluence (PRM 160.5), and Devils
Station (PRM 167 located upstream of the Devil Creek confluence). Six additional stations were
proposed for resident fish at the Montana Creek confluence (PRM 77), Whiskers Creek
confluence (PRM 105.1), Indian River confluence (PRM 142.1), Portage Creek confluence
(PRM 152.3), Fog Creek confluence (PRM 179.3), and Watana dam site (PRM 187.1).
However, the lack of access to CIRWG land necessitated a number of changes to the quantity
and location of telemetry fixed stations in the Middle River during 2013. Fixed stations planned
for the Portage Creek, Cheechako station, Chinook Creek, and Fog Creek were not installed due
to a lack of land access. The Slough 21 station was moved to a new location slightly upstream
(Powerline, PRM 146) to get as close to the CIRWG boundary as feasible (Figure 4.1-3).
Specific telemetry sites were not identified in the RSP, but were discussed in Section 5.8.2.1 of
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the Implementation Plan. The variance in fixed telemetry sites did not have a negative effect on
meeting the study objectives because regular, almost daily, aerial surveys were flown to mitigate
for the absence of these sites. Higher geographic resolution and greater numbers of fish
detections were obtained with the frequent aerial surveys.
4.1.7.5. Winter Study Sites
Figure 5.11-1 in the Implementation Plan depicted locations for winter sampling in FA-104
(Whiskers Slough). A few of the final sites selected in the field based on ice conditions were
altered from the proposed locations, including the addition of sites outside the Focus Area, and a
second Focus Area was sampled. Additional sites in and around FA-128 (Slough 8A) were also
made based on habitat type and ice conditions. These changes in sampling sites improved the
ability to evaluate the effectiveness of winter sampling techniques by increasing the number of
sampling sites and targeting suitable habitats for fishes.
Sampling Frequency 4.2.
AEA implemented the sampling frequency methods as described in the Study Plan with the
exception of the variances explained in Section 4.2.1. Sampling frequency varied among sites
based on study objectives. Winter fish sampling occurred monthly from February through April
2013 and was coordinated with the intergravel temperature monitoring, the underwater fish
observation using sonar (Appendix A, Section 3), the detectability of PIT and radio tags through
ice (Appendix A, Sections 4 and 5), and substrate characterization components. Following the
2013 winter fish distribution and abundance pilot study, sampling occurred seasonally during the
ice-free period. Break-up in 2013 was unusually late across Southcentral and Interior Alaska.
Sustained record-cold weather in April and May prevented substantial snowmelt or ice decay
until late May. Ice break-up activity was concentrated between May 25 and May 29 and the
Susitna River at Gold Creek was above flood stage from May 28 to June 4. Biweekly ELH
sampling was initiated prior to break-up (April 28 to May 3) and continued after ice-out and into
late June in an attempt to capture critical juvenile Chinook salmon out-migration from natal
tributaries to rearing habitats (Table 4.1-1). Fish distribution and abundance sampling was
completed during three sessions: July 7 to August 10, August 11 to September 4 and September
10 to October 4 in 2013. PIT tag interrogation antennas at Montana Creek, Whiskers Slough,
Slough 8A, and Indian River were installed between June 15 and June 21 and were operated
nearly continuously until early October (Figure 4.2-1). Rotary screw traps at Montana Creek,
Talkeetna Station, Curry Station, and Indian River were installed between June 8 and June 22
and operated on a 48-hours-on/72-hours-off schedule until late September and October (Figure
4.2-2). Stationary radio receivers were installed at the Montana Creek, Whiskers Creek, Lane
Creek, Gateway, 4th of July Creek, Indian River, Upper Indian, Powerline, and Devils Island
sites between June 4 and June 27 (Table 4.1-5). Fixed radio telemetry monitoring efficiency was
tested on a weekly basis (Table 4.2-1). Aerial surveys were conducted approximately weekly
June 22 through October 7 (Table 4.2-2) and continued monthly thereafter. The monthly
schedule is planned to continue through April 2014. .
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4.2.1. Variances from Study Plan
Early life history (ELH) sampling was proposed to occur every two weeks from break-up to July
1 (RSP Section 9.6.4.2). However, alevin and fry emergence was documented during April prior
to ice-out so an abbreviated sampling event (10 sites) was conducted in late April and early May
to gather additional information during this period. Thus, ELH sampling began in April and
continued into June. Sampling was conducted biweekly with the exception of one bi-weekly
event that was missed due to break-up and associated flood conditions.
IP Section 5.7.3 stated that rotary screw traps would be operated throughout the ice free period.
However, the Indian River trap sustained damage due to high flow conditions in early
September. The Curry rotary screw trap was used to replace the Indian River trap on September
10 due to the much higher catch rates at Indian River. This decision minimized the impact of
late-season trap damage on the study objectives by maintaining rotary screw trap operation in the
locations with the highest catch rates.
Fish Sampling Approach 4.3.
The initial task of this study consisted of a focused literature review in the IP to guide selection
of appropriate methods by species and habitat type, sampling event timing, and sampling event
frequency. Products from the literature review included the following:
• A synthesis of existing information on life history, spatial and temporal distribution, and
relative abundance by species and life stage.
• A review of sampling strategies, methods, and procedures used in the 1980s fish studies.
• Periodicity charts for each species within the study area (timing of adult migration,
holding, and spawning; timing of incubation, rearing, and out-migration).
• A summary of mainstem Susitna River habitat utilization for each species, by riverine
habitat type (main channel, side channel, side slough, upland slough, tributary mouth,
tributary).
• A summary of existing age, size, and genetics information.
• A summary of distribution of invasive species, such as northern pike.
Knowledge of behavior and life history of the target species is essential for effective survey
design. Fish sampling methods varied based on habitat characteristics, season, and species/ life
history of interest (Table 2-1). Timing of surveys depended on the study objectives and the
behavior of the target fish species. Since life stage-specific information was desirable, timing of
the surveys was matched to the use of the surveyed habitat.
A summary of relevant existing fish and aquatic habitat information collected in the Susitna
River study area was provided in the final Fish Distribution and Abundance Implementation Plan
filed with the FERC on March 1, 2013. The literature review focused on five study topics: (1)
resident and juvenile fish distribution and abundance in the Upper Susitna River (1980s and
2012); (2) adult salmon escapement and distribution (1980s and 2012); (3) salmon and trout
incubation and emergence (1980s); (4) aquatic habitat delineation (2012); and (5) open-water
flow routing modeling (2012). Although an abundance of data has been collected, the
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information summarized was selected primarily to guide site selection and the development of
sampling techniques that would be used to implement the Study of Fish Distribution and
Abundance in the Upper and Middle and Lower Susitna River (Studies 9.5 and 9.6).
Objective 1: Fish Distribution, Relative Abundance, and Habitat 4.4.
Associations
AEA implemented the methods for Objective 1 as described in the Study Plan with the exception of
the variances explained in Section 4.4.4. Two general approaches to fish sampling were used.
The first focused on gathering data on general fish distribution (presence). This sampling
involved a single pass with appropriate gear types without using block nets. To the extent
possible, the selected site locations and transects were standardized and the fish capture and
observation methods were repeated during each sampling event at a specific site to evaluate
temporal changes in fish distribution. The second sampling approach was to gather data on
relative abundance as determined by CPUE and density; complementary data on fish size, life
stage, and condition factor was also collected. Relative abundance sampling used block nets
whenever feasible to isolate each mesohabitat type (e.g., pool, riffle, glide) for sampling. Like
distribution sampling, the selected sites and transects, and fish capture and observation methods
(i.e., number of passes, amount of soak time, use of block nets) was standardized such that they
were repeatable on subsequent sampling occasions. For all sampling, main channel, off-channel,
and tributary habitats were further characterized in the field to the mesohabitat level (pool, riffle,
glide, etc.) for sampling purposes (appropriate gear selection, IP Appendix 3) and for study of
fish-habitat associations.
4.4.1. Task A: Fish Distribution Surveys
4.4.1.1. Field Methods
Fish distribution surveys included seasonal sampling events during the ice-free seasons with
year-round sampling in select Focus Areas. Various methods were chosen based on target
species, life stage, and water conditions. Snorkeling and electrofishing were preferred methods
for juvenile fishes in clearwater areas where velocities were safe. Minnow traps, beach seines,
set nets, and fyke nets were employed as alternatives in deeper waters and in habitats with
limited access, low visibility, or high velocities. For larger fishes, gillnets, seines, trotlines, hoop
traps, and angling were used along with the opportunistic use of fishwheels in conjunction with
the Salmon Escapement Study (ISR Study 9.7). Whereas snorkeling, minnow trapping,
backpack electrofishing, and beach seines were applicable to sloughs and other slow-moving
waters, gillnetting, boat electrofishing, hoop traps, and trot lines were more applicable to the
main channel. Two or more survey methods were selected for each site based on target species
and life stages. The decisions about what methods to apply were made by field crews after initial
site selection in coordination with Fish Distribution and Abundance Study Lead and the Fish
Program Lead and in accordance with state and federal fish sampling permit requirements.
Lastly, methods varied seasonally with the extent of ice cover. Methods for winter sampling
were based on winter 2012–2013 pilot studies and included DIDSON, underwater video,
minnow traps, electrofishing, fyke nets, and trot lines.
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4.4.1.2. Analytical Methods
For the purposes of describing juvenile salmon and resident fish distribution in the Middle and
Lower River, locations where species were documented during the various study components of
this study were pooled with other available information from 2012 and 2013 AEA fish tasks
within the study area. The list of data sources included: 2013 winter studies, 2013 early life
history sampling, 2013 rotary screw trapping, 2013 fish distribution and abundance sampling,
2013 PIT array detections, 2013 resident fish radio telemetry detections, 2013 directed fish
sampling efforts for interrelated studies, 2012 fish distribution sampling (AEA 2013a), 2013
resident fish catch at fish wheels (Study 9.7), and 2013 habitat suitability sampling (Study 8.5).
To describe seasonal distribution, fish collections were then assigned the following seasons:
winter (February 1 to April 14), salmon early life history (April 15 to June 30), early summer
(July 1 to August 10), late summer (August 11 to September 9), and fall (September 10 to
October 12).
4.4.2. Task B: Relative Abundance
4.4.2.1. Field Methods
Relative abundance surveys included seasonal events during the ice-free seasons using block nets
when feasible. When velocity, depth and width allowed, block nets were used to partition off-
channel habitats and tributaries into mesohabitat units (e.g. pool, riffle, glide, etc.) for relative
abundance sampling and gear appropriate for each mesohabitat type was selected based on IP
Appendix 3. Fish were processed in groups associated with the mesohabitat where they were
captured or observed. As mentioned above, methods were selected based on target species, life
stage, and water conditions. All methods were conducted with a level of effort consistent with
generating estimates of CPUE that facilitated comparison of counts or densities of fish over
space and time. This included calibration and quality control of methods and documentation of
conditions that affected sampling efficiency (such as visibility and turbidity, water temperature,
and conductivity) to ensure that consistent effort was applied within and among sampling units
and sampling events. Basic site and habitat information was collected for each mesohabitat
sampled and detailed records were kept on the level of sampling effort including soak times,
sampling duration, number of units, and specifications of gear used.
4.4.2.2. Analytical Methods
The sampling design, as proposed in the Study Plan, included specific fish distribution (one-pass
sampling) and abundance sampling sites, where multiple pass sampling efforts were to be
conducted. Sites identified as distribution sampling and relative abundance sampling have been
combined for estimates of CPUE because multiple pass sampling was not employed, thus
yielding a larger overall sample size.
The approach used to estimate CPUE was generally similar among the four types of relative
abundance protocols in the Middle and Lower River: Middle River Focus Area sampling, Middle
River non-Focus Area sampling, Middle River direct-sampling tributaries, and Lower River
mainstem transects. Mainstem CPUE estimates were derived for each mesohabitat type within a
macrohabitat unit and then averaged among macrohabitat units within each mainstem
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geomorphic reach and in the Middle River, separate averages were derived for habitats within
and outside of Focus Areas. For direct-sampling tributaries, CPUE was calculated specific to
mesohabitat type and then averaged among direct sample sites for each tributary. Although the
sampling design for the Middle and Lower River mainstem did not distinguish between various
main channel types (i.e., main channel, split main channel, and multiple split main channel),
average CPUE estimates for the main channel macrohabitat types have been generated at this
finer level of classification. When sampling within a mainstem macrohabitat site or a direct
sampling site included multiple mesohabitat units of the same type (e.g., two distinct pools),
catch and effort were summed at the mesohabitat level prior to averaging. In all cases, estimates
were derived specific to the each of the three Fish Distribution and Abundance sampling events
(i.e., early summer, late summer, and fall).
Although CPUE estimates were derived in a similar manner across the four types of relative
abundance sampling in the Middle and Lower River study area, it is important to note that these
study components had different study designs and utilized different site selection processes.
Therefore, caution should be used when making quantitative comparisons among areas where
different protocols were used. Tributaries sampled in the Middle River study area were non-
randomly selected and thus should not be used to draw inferences about other Middle River
tributaries. Furthermore, direct sampling sites were not randomly selected with a tributary, and
therefore, the relevance of the averaged CPUE estimates to the unsampled portions of a direct
sample tributary is unknown.
Gear-specific CPUE estimates were derived for each species, as well as Pacific salmon life
stages. For the purposes of this ISR, the seven most commonly employed gear types were used
to determine CPUE including: backpack electrofishing, boat electrofishing, seining, snorkeling,
fyke netting, hoop trapping, and minnow trapping. Additional gear types including angling, dip
netting, gillnetting, and trot lining will be analyzed for the Updated Study Report. For backpack
and boat electrofishing, CPUE was estimated as the number of fish captured per hour of
electrofishing pulse time. Snorkeling and seining CPUE estimates were standardized as the
number of fish captured or observed per 1,000 m2 sampled. For passive sampling techniques
(i.e., fyke nets, hoop traps, and minnow traps), CPUE was calculated as the number of fish
captured per trap or net. Additional details regarding CPUE calculations and associated gear-
specific sample sizes can be found in Appendix E.
4.4.3. Task C: Fish Habitat Associations
In conjunction with Tasks A and B, data were collected for fish distribution and abundance by
mesohabitat type nested within macrohabitats. For the purposes of demonstrating progress in the
ISR, fish observations were used for preliminary reporting of geomorphic reach-specific
mesohabitat habitat associations by season. Fish observations included catch and observational
data from spring early life history sampling and seasonal systematic fish distribution and
abundance sampling including Middle River GRTS and Lower River transect sites.
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4.4.4. Variances from Study Plan
4.4.4.1. Sampling Unit Length
Fish distribution and abundance sampling unit lengths for main channel, side channel, side
channel complex, and bar island complex habitat types along transects and GRTS locations was
500 m (0.3 mi) when boat electrofishing or drift-netting was feasible as recommended in the
April 1, 2013 Study Plan Determination. However, the level of effort required to effectively
cover and gather a representative sample of units 500 m (0.3 mi) in length using techniques other
than boat electrofishing or drift-netting was deemed to not be practical in the field. Therefore,
when these techniques were not feasible, sampling units were shortened to 200 m (656 ft) for
main channel units.
The Fish Distribution and Abundance sampling effort included 61 main channel units and 101
off-channel units that were sampled during each of three sampling events using multiple gear
types . Each event required approximately 100 crew-days to complete even with the shortened
sampling unit lengths for selected gear-types in the main channel habitats. Sampling 500 m (0.3
mi) with every gear type in main channel habitats would have added an additional 50 crew-days
to each sampling period, compromising AEA’s ability to adhere to the seasonal sampling regime.
4.4.4.2. Sampling Approach
In the Revised Study Plan (Section 9.6.4.3.1), AEA proposed that relative abundance sampling
would include multiple-pass sampling when electrofishing, snorkeling, and minnow trapping
were employed. However due to ADF&G permit stipulations limiting electrofishing efforts to
one pass, the April 1 FERC SPD recommendation that minnow traps be set for 24-hrs, and the
extensive level of effort involved in three pass snorkeling 200 m (656 ft) long sampling units,
single-pass sampling was conducted. Study teams experimented with comparing three-pass
depletion minnow trapping to 24-hour sets for relative abundance sampling during the July
sampling event and found that the level of effort required to return to sites to check and re-bait
traps impeded the progress of sampling. Ultimately the FERC recommendation of 24-hour or
overnight soaks was adopted. The FERC Study Plan Determination recommended placing
minnow traps at a density of 20 traps per 200 m (656 ft) of habitat sampled and placing traps
strategically in places most likely to catch fish. To increase catch and account for more complex
habitats, field crews were given the option to place 1 or 2 minnow traps per 10 m (33 ft) of
sampling unit. To streamline sampling, after initial sampling with varying soak times for
different gear types, fyke net and hoop trap soak times were adjusted to a sampling regime that
matched that of minnow trapping: a 24-hour overnight soak. Relative abundance sampling did
involve the isolation of the sampling unit with block nets whenever feasible and a generally
greater level of effort (e.g. more frequent seine pulls) than distribution sampling. The time
fished for all drift gillnet sets was significantly less than 30 minutes, with the longest drift
recorded being 15 minutes. This is a variance from the Implementation Plan (Section 8.1) which
suggested a standard time of 30 minutes or until the net was saturated with fish. The short drift
time recorded in the field was due to the speed of the current carrying the drifting net through the
prescribed area. The set duration for hoop traps was consistently greater than the recommended
12 hours or less. The majority of hoop traps set were soaked between 15 and 22 hours. The
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logistics of setting overnight traps and retrieval within 12 hours was difficult, based on the travel
distance between sites and boat launches.
In Appendix 3 of the Implementation Plan, Protocol for Site-Specific Gear Type Selection, AEA
recommended that three or more sampling techniques be used at each site, but a minimum of two
sampling techniques were to be attempted per habitat (or mesohabitat) type. However, during
implementation there were times when only one sampling technique was used in a habitat (or
mesohabitat) unit. This occurred in habitats that were not conducive to multiple sampling
techniques (e.g., shallow habitats with high water temperatures and low specific conductivity and
high aquatic vegetation cover were only minnow trapped or very shallow, high velocity riffles
were only backpack electrofished). The decision to use applicable methods was made in the
field based on site conditions while using the Gear Selection Appendix as a guide. This meant
that sampling techniques were not forced into habitat where they would not be effective (e.g.,
placing baited minnow traps where the velocity was too high).
The Implementation Plan (Section 5.1) describes the use of a clove oil bath as anesthesia during
handling and transferring fish when necessary. Clove oil anesthesia was used for sensitive or
difficult to handle fish such as juvenile salmon or lamprey. Anesthesia was not used for all fish
before handling. A clear, water-filled viewing chamber with an attached ruler was used to
measure small fish and fish were weighed within a small tub of water. The larger fish were
handled as little as possible, transferring them onto the measuring board where they were
scanned for PIT tags and tissue was removed for genetic analysis before they were weighed.
Field observations of mortality from anesthesia and attempted recovery were documented.
4.4.4.3. Lower River Habitat Classification
After the initial field visit and review of the habitat units across each transect, the following
changes were made to the Lower River habitat classification. The habitat types of Main Channel
(MC) and Bar Island Complex (BIC), and the habitat types of Side Channel (SC) and Side
Channel Complex (SCC), were each combined to form two larger habitat type groups (MC/BIC
and SC/SCC), due to their degree of similarity in the field. On a given transect, multiple MC,
SC, SCC and BIC habitats were encountered but only one was sampled (e.g. one MC or one BIC
habitat was sampled and one SC or one SCC was sampled per transect) so as to not over
represent main channel habitat types. The distribution of habitat types sampled among the 44
sites varied from that originally proposed (Table 4.1-4). Pre-field site selection review indicated
that the original site selection would sample 81.8 percent main and side channel habitat and 18.2
percent off-channel habitat. Since the 1980s data indicated that fish would likely be using much
of the off-channel habitat, the width of transects was increased to 2 km to allow for inclusion of
the rarer “clearwater” off-channel habitat types (sloughs and tributaries). This increased the
selection of off-channel habitats from 18.2 percent to 54.5 percent. There were no tributary
deltas (as defined in the IP Section 4.4.4 based on geomorphic mapping) present within any of
the transects, but tributary mouths were included as off-channel habitat types. Upland slough
mouths were added as a habitat type. Abundance transects were originally outlined in the IP
(Section 5.4) as Transects PRM 100.3, PRM 70.8, PRM 56.1 and PRM 34.0, but with the
inclusion of slough mouths, the transect with the most habitat unit in reach LR-2 was PRM 63.5.
This transect replaced Transect PRM 56.1 for relative abundance sampling in LR-2.
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Objective 2: Seasonal Movements 4.5.
AEA implemented the methods for Objective 2 as described in the Study Plan with the exception of
the variances explained in Section 4.5.3.
4.5.1. Task A: Document the timing of downstream movement and catch for all
fish species using out-migrant traps.
As described in Section 4.1.3 and Section 4.2, four rotary screw traps were deployed in the
Middle and Lower River shortly after ice break-up (Figure 4.1-10). In addition to collection of
data on migratory timing, size-at-migration, and growth, rotary screw traps served as a source for
PIT tagging juvenile fish (Objective 2, Task B), collecting fish for radio-tagging (Objective 2,
Task B), collecting fish for stomach content analysis in support of the River Productivity Study
(Study 9.8), and collecting tissue samples to support other studies (Objectives 4, 5 & 7) including
the Genetic Baseline Study for Selected Fish Species (Study 9.14).
4.5.2. Task B: Describe seasonal movements using biotelemetry.
4.5.2.1. Field Methods
Biotelemetry techniques included radio telemetry and Passive Integrated Transponder (PIT)
technology. Half duplex PIT tags (12 and 23 mm) were surgically implanted in fish greater than
60 mm (2.4 in) to monitor movement and growth. Fish for PIT tagging were captured
opportunistically during fish distribution and abundance sampling, targeted sampling for juvenile
Chinook salmon, and by rotary screw traps.
PIT tagging in the Middle and Lower River was focused in proximity to array antennas and
included the Focus Areas, the Susitna between PRM 102.4 and 152.3, and rotary screw traps.
Recaptured fish provided information on the time and distance travelled since the fish was last
handled and growth. PIT tag antenna arrays with automated data logging were installed and
operated at Montana Creek, Whiskers Slough, Slough 8A, and Indian River (Figure 4.1-10).
During the 2013 open-water period (June to October), a total of 5,657 PIT tags were implanted in
11 different fish species in the Middle and Lower River (Table 4.5-1). Coho salmon were the
most frequently tagged species (n=2,092), followed by juvenile Chinook salmon (n=1,696),
Arctic grayling (n=378), rainbow trout (n=309), round whitefish (n=300), and burbot (n=223).
For selected species, radio transmitters were surgically implanted in adult fish of sufficient body
size. Collections of fish for tagging were distributed temporally and spatially in the Lower and
Middle River to describe seasonal movements. Radio-tagged fish were tracked from July
through October 7, 2013 using weekly aerial surveys in conjunction with the Salmon
Escapement Study (Study 9.7) to describe seasonal movements (Table 4.2-2). Aerial srveys
continued on a monthly schedule thereafter. Aerial surveys were partitioned into mainstem
Susitna and tributary zones (Figures B20 and B21). A target of 30 Arctic grayling, burbot, Dolly
Varden, longnose sucker, northern pike, lake trout, rainbow trout, humpback whitefish, and
round whitefish was set for radio-tagging during non-spawning periods. Target numbers for
radio tagging were met for Arctic grayling (35) and rainbow trout (44) and nearly met for
longnose sucker (28) and round whitefish (21) (Table 4.5-2). Targets were not reached by
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September for less abundant species, but tagging efforts will continue in the next year of study.
Lake trout have not been captured during any sampling in the Middle or Lower River. A
detailed description of tagging location by species is found in Appendix B. All tags released
from June through August 31 had sufficient battery life to broadcast a signal through August 31.
According to the manufacturer, the earliest date the battery life of a tag may stop it from
broadcasting a signal is September 25. Using minimum tag life estimates, up to 23 tags released
in the Middle and Lower River could stop transmitting by the end of 2013.
4.5.2.2. Analytical Methods
Analysis of radio tag detections was conducted in accordance with the Study Plan (IP Section
5.8.2)
4.5.3. Variances from Study Plan
4.5.3.1. PIT Tag Interrogation System
The IP proposed that the detection efficiency of PIT tag interrogation systems be determined
using indirect methods as described by Connolly et al. (2008). This approach relies on the
detection of fish at multiple locations (i.e., antennas located upstream and downstream) to
identify missed detections of fish passing a given antenna. However, the limited availability of
appropriate sites for antenna placement in 2013 precluded this approach because antenna sites
could not be arranged in a longitudinal series; instead antennas were installed at a single site
within a given tributary or slough. Handheld detections of fish upstream or downstream of a
given PIT tag antenna during initial tagging and following recapture by rotary screw trap,
electrofishing, or other methods may provide some relative indication of the detection efficiency
of that antenna. Whether the number of such recaptures is adequate to provide an estimate of
detection efficiency will be determined during ongoing analysis and will be presented in the
Updated Study Report (USR).
As an alternative approach for estimating detection efficiency, AEA measured the read range of
an antenna for a given tag size. This information, combined with the antenna dimensions, water
depth over the antenna (for a swim-over configuration), and wetted channel width was used to
estimate the percentage of the channel’s cross-sectional area in which a tag would be detected.
This information was routinely recorded during site visits to download data. This approach did
not account for behavioral factors that could influence detection, such as fish position relative to
the channel bottom or margins, or swimming speed relative to the antenna. Nonetheless, this
approach offered a means of quantifying the probability of a fish being detected as it moved past
an antenna.
In addition, detection efficiency was evaluated by drifting neutrally buoyant test tags past an
antenna and calculating the percentage of tags that were detected. Again, this approach did not
account for behavioral factors that would influence detection, but it did offer an additional means
of estimating the probability of detection. This effort occurred during site visits to demobilize
and winterize antennas in October 2013.
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4.5.3.2. Radio Tagging Targets
The following FERC recommendation (SPD B-135) was not adopted by AEA:
“To the extent possible given the constraints of field sampling conditions, we recommend
that AEA target its fish sampling to meet the following specific objectives: (1) a
minimum of 10 tags per species be allocated for tagging adult grayling and rainbow trout
of sufficient size for spawning at tributary mouths during the spring sampling event; (2) a
minimum of 10 tags should be allocated for tagging adult Dolly Varden of sufficient size
for spawning at tributary mouths during a late summer or early fall sampling event; (3) a
minimum of 10 tags should be allocated for tagging adult whitefish prior to spawning in
early September; and (4) a minimum of 10 tags should be allocated for tagging burbot in
the early fall prior to fall or winter spawning migrations.”
The FERC-recommended approach targets fish when they will potentially be at a phase of their
life history (pre-spawning development) when they are more energetically taxed (as a result of
limited food availability during the winter months) and potentially more sensitive to the stresses
associated with handling. In particular, rainbow trout and Arctic grayling spawn in the early
spring and allocate the majority of their pre-winter energetic gain toward development of
gametes. They have limited energy reserves remaining for metabolic processes in the spring.
Further, sexually maturing fish have less space in their abdominal cavity due to enlarged sex
organs; there is less room for insertion of a tag and there is a higher chance of internal injuries
during the surgical procedure. Surgically tagging these species in close temporal proximity to
their spawning migration (e.g., “immediately prior”) may have too high a metabolic cost and a
higher risk for injury that could increase post-tagging mortality relative to fish tagged outside
this life history phase. The average tag life, in days, for rainbow trout and Arctic grayling tags is
450, 652, and 901 for the smallest to the largest tags, respectively. AEA recommended that the
primary period for tagging these fish be the summer or fall; the time when they are at an
energetic maximum and likely to be most resilient to the stresses associated with handling. The
available tag life should allow data to be collected the following year on spawning migrations
and spawning habitat destinations. Tagging the identified species during the specified periods
was done based on the surgeon’s discretion (4.5-3).
4.5.3.3. Aerial Surveys
Section 5.8.2.2 of the Implementation Plan stated: “The proposed frequency of aerial surveys
would provide a means of focusing a higher-resolution and time-intensive tracking effort on
identifying exact locations of spawning and holding fish. To do this, the most recent observed
river locations (to the nearest 1 kilometer [0.62 mile]) of all fish “at large” would be made
available to the aerial survey team. During the survey, the location of all detected fish would be
compared to the last seen location from previous surveys to ascertain whether its position had
changed by more than 2 kilometers (1.25 miles). When tagged fish were within 2 kilometers of
their last seen location, the helicopter would circle at a lower altitude to pinpoint the fish location
to mainstem, side channel, or slough habitats.”
Survey methods for radio-tagged resident fish were modified from the Implementation Plan to
accommodate the high number of frequencies that needed to be scanned for salmon and resident
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fish. Resident tag frequencies were programmed into a receiver and scanned automatically. No
manual tracking, directed searching, or identification of habitat type was conducted during the
period when adult salmon were being tracked. Resident tag frequencies were tracked manually
during the period when adult salmon tags were not present. Specific aerial survey methods were
not identified in the RSP, but were described in Section 5.8.2.2 of the Implementation Plan. The
variance in aerial telemetry survey method may not have had a negative effect on meeting the
stated objectives of the study because geographic positions of the tags could be related to digital
habitat classifications made by other studies in AEA’s program. However, the lack of directed
effort at pinpointing tag locations (accuracy less 100 yd for some resident fish tags) may make
habitat use inferences less accurate if habitat delineations were much smaller than the resolution
of the tag positions.
Objective 3: Early Life History 4.6.
AEA implemented the methods for Objective 3 as described in the Study Plan with the exception of
the variances explained in Section 4.6.5.
4.6.1. Task A: Describe emergence timing of salmonids.
In conjunction with the Intergravel Monitoring component of the Fish and Aquatics Instream
Flow Study (Study 8.5), salmon redds in selected side channels and sloughs were monitored on a
monthly basis throughout the winter in Focus Areas. Studies included monitoring of surface and
intergravel water temperatures and spawning substrate composition. This task was conducted as
part of the Fish and Aquatics Instream Flow Study (Study 8.5) with methods presented in Section
4.5.1.2.1 of that ISR.
4.6.2. Task B: Determine movement patterns and timing of juvenile salmonids
from spawning to rearing habitats.
Bi-weekly sampling to document the distribution of newly emerged salmon in select Focus
Areas occurred from ice-out through July 1 (Figure 4.1-1). Six Focus Areas met the criteria of
having both spawning and rearing habitat and were selected for sampling (Table 4.1-1).
Sampling sites included three designated 40 m (131 ft) sampling units immediately downstream
of a documented Chinook, chum, coho or sockeye spawning area (these were tributary mouths or
side sloughs at some Focus Area locations) and three 40 m (131 ft) rearing habitat sampling
units. Electrofishing, seining, fyke nets, and minnow traps were the primary methods for
collecting salmon during the early life stage sampling. Sampling events took place from April
through June as described in Section 4.2.
4.6.3. Task C: Determine juvenile salmonid diurnal behavior over season.
In the Study Plan (RSP Section 9.6.4.3.3) AEA proposed that sampling schedules would
encompass daylight, twilight, and evening periods. In 2013, this was accomplished by passive
sampling techniques (minnow traps, fyke nets, hoop traps, trotlines, rotary screw traps, PIT
interrogation sties, stationary radio telemetry receivers) during the night and crepuscular periods.
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4.6.4. Task D: Collect baseline data to support the Fish Stranding and Trapping
Study.
The focus of this task was to support the stranding and trapping component of the Fish and
Aquatics Instream Flow Study (Study 8.5). Fish distribution sampling occurred at Focus Areas
and at representative habitat units to identify seasonal timing, size, and distribution among
habitat types for fish (particularly less than 50 mm [2 in]). Electrofishing, seining, fyke nets, and
minnow traps were the primary methods for collecting salmon fry. Additionally, downstream
migrant traps (Objective 2, Task A) were used to monitor the size of fish over the season to
identify the timing associated with fish exceeding the 50 mm (2 in) length threshold.
4.6.5. Variances from Study Plan
The RSP and Implementation Plan did not include an objective for salmon early life history
sampling outside of Middle River Focus Areas or in the Lower River (IP Section 5.5). When
AEA adopted the FERC recommendation of seasonal sampling in mid-July and late August/early
September, additional locations were added to gather information during the period from ice
break-up to July.
Objective 4: Document Winter Movements and Timing and 4.7.
Location of Spawning for Burbot, Humpback Whitefish, and
Round Whitefish
AEA implemented the methods for Objective 4 as described in the Study Plan with no variances.
Radio tags have been surgically implanted in seven burbot, seven humpback whitefish, and
fourteen round whitefish in 2013 (Table 4.5-2). Fish capture methods included fishwheels,
rotary screw traps, beach seines and hoop traps. Ongoing tagging and tracking will be conducted
in accordance with the Study Plan.
Objective 5: Document the Seasonal Size/Life stage Structure, 4.8.
Growth, and Condition of Juvenile Anadromous and Resident
Fish by Habitat Type
AEA implemented the methods for Objective 5 as described in the Study Plan with the exception
of the variances explained in Section 4.8.1. In conjunction with Objectives 1 and 3, captured fish
were identified to species and classified to life stage or smolt index when possible. A summary
of fish length-at-maturation for the region was used as a basis for assigning life stages (Table
4.8-1). Each time a gear was used for sampling, a random sample of 25 individuals per species,
life stage, and site were measured for fork length (FL) in mm and measured in grams. For
species without a forked tail (e.g., sculpin and burbot), total length was measured laterally along
the mid-line from the anterior edge of the snout to the posterior edge of the tail. Total sample
sizes of fish measured for length and weight by River Segment are presented in Table 4.8-2.
Species were classified by life stage (Table 4.8-1) and when sample sizes were sufficient, natural
breaks in length-frequency were used to further refine size bins with an emphasis on anadromous
salmon less than 50mm (2 in). Recaptured PIT-tagged fish (Objective 2 Task B) provided
growth information. The number of fish PIT-tagged and recaptured is presented in Table 4.8-3.
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Parameters recorded in each habitat unit included the number of fish by species and life stage;
fork length; weight; global positioning system (GPS) location of sampling unit; time of
sampling; weather conditions; water temperature; water transparency; behavior; and the location
and distribution of observations.
For the ISR, condition factors have been compared by habitat for Chinook salmon and Arctic
grayling only. Prior to analysis of fish condition by habitat type, outliers that might skew
comparisons were identified and removed. A log-log regression on length vs. weight for all
measured fish within a species was fitted, including fish captured in migrant traps. The Grubbs
test (Grubbs, 1950, Lukasz, 2011) was then used for sequentially identifying outliers in the
residuals from these regressions. The experiment-wise error for the outlier removal for each
species was maintained at 0.05 by using alpha of 0.05 divided by the total number of outliers for
each sequential test. The resulting condition factors were also evaluated to ensure there were no
obvious differences among size or age classes of fish before combining. Fish condition, or
wellbeing, was estimated using Fulton’s condition factor where the coefficient of condition, K-
FL was derived from the formula: K-FL = W x 105/L3, where K-FL = condition factor by fork
length, W = weight of fish in grams, and L = fork length of fish (mm). Specific growth rates
were estimated as SRG= 100*(ln(L2) –ln(L1))/(d2 - d1), where L2 = mean length on day (d) 2
and L1 = mean length on day (d) 1, and (d2 - d1) is the number of days between
measurements. When all data were combined, fish condition factors were relatively stable across
life stages, although estimates for fry were more variable and perhaps higher for Arctic grayling
(Figure 4.8-1). Therefore, life stages were combined for the habitat analysis, but fry (less than
50mm (2 in) for Chinook; less than 60 mm (2.4 in) for arctic grayling) were not included. The
total sample sizes of fish included in the condition factor analysis by Geomorphic Reach or
Tributary are included in Table 4.8-4. Note that fish from distribution and abundance sampling
(Objective 1, Section 4.4), ELH studies (Objective 3, Section 4.6), and some opportunistic
sampling with associated habitat data were included in this analysis.
4.8.1. Variances from Study Plan
The Study Plan stated that each time sampling gear was checked, a random sample of 25
individuals per species, life stage, and site would be measured for fork length (FL) and weighed
(IP Section 5.1.5). However, the FERC SPD mistakenly interpreted AEA’s study plan as
proposing to measure and weigh all fish and no modifications were recommended (SPD p. B-
130). Due to ADF&G fish collection permit restrictions on fish handling; only the first 25
individuals of each species were weighed and measured during each check of a rotary screw trap.
The sample size of 25 measurements per species per life stage per site was consistent with
collecting the data necessary to evaluate length frequency distributions and condition factor for
sampled fish.
As an initial step towards assigning age-classes to the 2013 fish collections, a literature review
was conducted compiling information collected in the Susitna Basin during the 1980s
hydropower licensing efforts and relevant studies from Alaska. The literature review revealed
substantial individual variability in growth and overlap in sizes among age classes, particularly
for fish two years of age and older. The review also found considerable variability in growth and
size-at-age from different locations or regions within the basin adding further ambiguity to the
task of assigning size-based ages. AEA determined that ages could not be assigned with
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certainty to Susitna River fish based on length. The objective of documenting the seasonal age-
class structure of juvenile anadromous and resident fish by habitat type (RSP Section 9.6.4.3.5)
was therefore replaced with documenting seasonal size-structure by habitat type. Evaluating
habitat associations by size instead of age will continue to meet the objective of documenting the
seasonal life stage use, growth, and condition of species by habitat type.
Objective 6: Document the Seasonal Distribution, Relative 4.9.
Abundance, and Habitat Associations of Invasive Species
(Northern Pike)
AEA implemented the methods for Objective 6 as described in the Study Plan with no variances.
Northern pike were likely established in the Susitna River drainage in the 1950s through a series
of illegal introductions (Rutz 1999). The proliferation of this predatory species is of concern
owing to their negative effect on salmonids and other species such as stickleback. Rutz (1999)
investigated movements of northern pike in the Susitna River using radio telemetry and
investigated northern pike predation on salmonids by analyzing stomach contents of juvenile
pike captured with minnow traps. Both of the fish capture methods used by Rutz (1999) were
used in the current study, as well as angling, and other methods to capture northern pike. The
presence and habitat associations of northern pike and other invasive fish species were
documented during fish capture and observation sampling events associated with Objectives 1
and 2. Five northern pike were radio-tagged and tracked in the Lower River in 2013. The target
size for radio-tagging is 30 fish; tagging efforts are ongoing.
Objective 7: Collect Tissue Samples from Juvenile Salmon and 4.10.
All Resident and Non-Salmon Anadromous Fish
AEA implemented the methods for Objective 7 as described in the Study Plan with no variances. In
support of the Genetic Baseline Study for Selected Fish Species (Study 9.14), fish tissues were
collected opportunistically in conjunction with all fish capture events. The target species and
number of total samples are reported in the ISR for Study 9.14. Tissue samples included an
axillary process from all adult salmon, caudal fin clips from fish greater than 60 mm (2.4 in), and
whole fish less than 60 mm (2.4 in). A summary of tissues collected for genetic baseline
development as part of this study is presented in Table 4.10-1.
Winter Sampling Approach 4.11.
AEA implemented the methods for winter sampling as described in the Study Plan with no
variances. In 2013, winter pilot studies were conducted at FA-104 (Whiskers Slough) and FA-
128 (Slough 8A) in the Middle River. These sites were selected based on their accessibility from
Talkeetna, diversity of habitat types, and because sampling in the 1980s and 2012 revealed that
these sites were used for spawning as well as rearing by salmonids. Three winter pilot studies
were initiated in February 2013 focusing on (a) intergravel temperature, dissolved oxygen, and
water-level monitoring; (b) winter fish observations using DIDSON and underwater video; and
(c) winter fish sampling techniques. Summary results and recommendations for winter fish
sampling using a variety of techniques; underwater observations using DIDSON and underwater
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video; and evaluation of PIT and radio tags detectability under ice in cold temperatures are
presented in Appendix C.
Overall study objectives for the winter pilot study were to:
1. Evaluate the effectiveness and feasibility of winter sampling methods for each study
including: underwater fish observations via DIDSON sonar and underwater video, and
fish population estimates using minnow traps, seines, electrofishing, trotlines, PIT tags,
and radio tags.
2. Assess winter sampling logistics. This included safety, sampling methods in different
habitat types under varying degrees of ice cover, transportation and access to and from
sample sites, travel time, and winter-specific gear needs.
3. Evaluate the feasibility of sampling during spring break-up.
4. Develop recommendations for winter 2013/2014 study efforts.
Fish Sampling Techniques 4.12.
A combination of gillnet, electrofishing, angling, trot lines, minnow trappings, snorkeling,
fishwheels, out-migrant trapping, beach seining, and fyke netting techniques were used to sample
or observe fish in the Lower River and Middle River, and those fish moving in and out of
selected sloughs and tributaries flowing into the Susitna River. Techniques selected varied based
on habitat characteristics, season, and target species/life stage. All fish sampling and handling
techniques described within this study were selected in consultation with state and federal
regulatory agencies and sampling has been conducted under state and federal biological
collection permits. Limitations on the use of some methods during particular time periods or
locations (e.g. no electrofishing when adult salmon are present) played a role in the selection of
sampling techniques.
4.12.1. Gillnets
Variable mesh gillnets (7.5-ft-deep panels with 1-inch to 2.5-inch stretched mesh) were deployed
in appropriate habitat. In open water and at sites with high water velocity, gillnets were
deployed as drift nets, while in slow water sloughs, gillnets were deployed as set (fixed) nets.
The location of each gillnet set was mapped using hand-held GPS units and marked on high-
resolution aerial photographs. To reduce variability among sites, soak times for gillnets were
standardized; all nets were retrieved a maximum of 30 minutes after the set was completed. The
following formula was used to determine drifting time:
T = ([(set time + retrieval time)/2] + soak time)
4.12.2. Electrofishing
4.12.2.1. Backpack Electrofishing
A Smith-Root LR-24 backpack electrofishing unit was operated by a trained field crew leader
who was assisted by two people with dipnets. Each backpack unit was fitted with a standard
Smith-Root cathode and a single anode pole with a steel ring. Electrofishing was often paired
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with snorkel surveys, where snorkel surveys were conducted first as a reconnaissance to make
sure there were no large salmonids in the area. Single-pass fish distribution electrofishing
surveys were conducted through the selected study reach moving in an upstream direction.
Block nets were used for relative abundance sampling when sites conditions allowed.
Depending on stream width, an additional crew leader sometimes operated a second
electrofishing unit. All stunned fish were captured with dipnets away from the electric field and
held in buckets for later processing.
All backpack electrofishing procedures followed NMFS (2000) Guidelines for Electrofishing
Waters Containing Salmonids Listed Under the Endangered Species Act. Personnel operating
electrofishing units were trained and certified as per ADF&G permit requirements. Backpack
electrofisher settings were determined in the field based on water quality conditions, professional
judgment, and the overall goal of minimizing impacts to fish health (Temple and Pearsons 2007).
Prior to electrofishing, ambient water chemistry was recorded including conductivity
(microSiemens), turbidity (nephelometric turbidity unit [NTU]), and surface water temperature
(°C) with a digital meter at the downstream end of sampling site to help determine initial
backpack electrofishing unit settings. In all cases, the electrofishing unit was operated and
configured with settings consistent with guidelines established by the manufacturer (Smith-Root
2009), ADF&G (Buckwalter 2011) and NMFS (2000). An ADF&G-generated table that
recommends target voltage settings for juvenile salmonid sampling in cold water was used as a
reference at the onset of sampling (Buckwalter 2011). The location of each electrofishing unit
was mapped using hand-held GPS units and marked on high-resolution aerial photographs. Start
and stop times were recorded to quantify sampling effort between surveys. Habitat
measurements were collected at each study site location. All captured fish were identified to
species, measured for length, and returned to the stream unharmed. For each sample unit, fish
capture data and sampling effort (e.g., electrofishing ‘power on’ recorded in seconds) was
documented separately so that CPUE could be calculated. One of the ADF&G Fish Resource
Permit stipulations in 2013 was that electroshockers could not be used in anadromous waters in
the presence of adult salmonids including trout or char. ADF&G further stipulated that
electrofishing would be limited to one pass.
4.12.2.2. Boat Electrofishing
Boat-based electrofishing was conducted while drifting in a downstream direction by an
experienced three- or four-person field crew. Above Devils Canyon, a 16 ft cataraft mounted
with a Smith-Root Inc. Type IV electroshocking unit was deployed with one person on the
netter’s platform and one person operating the electrofishing units and guiding the boat using
oars or a small outboard motor. In the main channels and side channels from MR-5 downstream,
a Smith-Root Inc. high-output Generator Powered Pulsator (GPP 5.0) or a Type IV
electroshocker unit was operated out of a 160-200 HP outboard jet-drive riverboat manned by a
three-person crew; two netters and an boat operator. The electroshocking procedure consisted of
maneuvering the boat downstream along the shoreline of each sample site while occasionally
detouring towards the thalweg to avoid shoreline hazards. Two crew members positioned on a
netting platform at the bow of the boat, netted stunned fish while a third individual operated the
boat and electroshocking unit. The two netters attempted to capture all fish observed near the
boat. Captured fish were immediately placed into an onboard live-well. Fish species that
avoided capture were enumerated and recorded as “observed”.
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Boat electrofisher settings were determined in the field based on water quality conditions
following Buckwalter 2011, professional judgment, and the overall goal of minimizing impacts
to fish health (Temple and Pearsons 2007). Prior to electrofishing, ambient water chemistry was
recorded including conductivity (microSiemens), turbidity (NTU), and surface water temperature
(°C) with a digital meter at the downstream end of sampling site to help determine initial unit
settings (Temple and Pearsons 2007). In all cases, the electrofishing unit was operated and
configured with settings consistent with guidelines established by the manufacturer and ADF&G
(Buckwalter 2011). The field team recorded a GPS location at the upstream start of each stream
or sample segment prior to moving downstream to sample. Start and stop times were recorded to
quantify sampling effort between surveys. Habitat measurements were also collected at each
study site location. At deep-water sites, boat electroshocking was conducted along the channel
margin. All captured fish were identified to species, and a subsample was measured for length,
and returned to the stream unharmed. For each sample unit, fish capture data and sampling effort
(e.g., electrofishing ‘power on’ recorded in seconds) was documented separately so that CPUE
could be calculated. One of the ADF&G Fish Resource Permit stipulations in 2013 was that
electroshockers could not be used in anadromous waters in the presence of adult salmonids
including trout or char. ADF&G further stipulated that electrofishing would be limited to one
pass. Because of safety concerns, electrofishing surveys were only conducted during daylight
hours.
4.12.3. Angling
Angling with hook and line was an effective way to collect fish samples for select target species
under certain conditions. During field trips organized for other sampling methods, hook-and-line
angling was conducted on an opportunistic basis using artificial lures or flies with single barbless
hooks. The primary objective of hook-and-line sampling was to capture fish for radio-and PIT
tagging and to determine presence; a secondary objective was to evaluate seasonal fish
distribution. Because it was labor and time intensive, angling was best used as an alternative
method if other more effective means of sampling were not available. Angling was also used in
conjunction with other methods, particularly if information on the presence and size of adult fish
was required.
4.12.4. Trot Lines
Trotlines consisted of a long line with a multitude of baited hooks and were typically anchored at
both ends and set in the water for a period of time. Trot line sampling was one of the more
frequently used methods during the 1980s and was the primary method for capturing burbot;
however, because trot lines are generally lethal, their use was infrequent and limited to two
summer sampling events in the Middle and Lower River. Trot lines consisted of 14 to 21 ft of
seine twine with six leaders and hooks lowered to the river bottom. Trot lines were checked and
re-baited after 24 hours and pulled after 48 hours. Hooks were baited with salmon eggs, herring,
or whitefish. Trot line construction and deployment followed the techniques used during the
1980s studies as described by ADF&G (1982). As per ADF&G Fish Resource Permit
stipulations, all salmon eggs used as bait were commercially sterilized or disinfected with a 10-
minute soak in a 1/100 Betadyne solution prior to use.
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4.12.5. Minnow Traps
Both wire and fabric collapsible minnow traps were used in 2013. The wired two-piece minnow
traps were 16.5 in long, with a 9 in diameter, and had a 1 in opening. The collapsible traps had a
length of 18 in and a width of 10 in. The openings of the collapsible trap were 2.5 in diameter.
Minnow traps were baited with commercially processed salmon roe. As per ADF&G Fish
Resource Permit stipulations, all salmon eggs used as bait were commercially sterilized or
disinfected with a 10-minute soak in a 1/100 Betadyne. After roe was sterilized, 1 Tbsp of roe
was measured out and placed in a 1-ounce plastic Whirl-Pak bag (Fort Atkinson, WI, USA) or
plastic canister. Filled plastic bags were perforated using a fork or utility knife before bait was
placed inside the trap.
One to two minnow traps were deployed for every 10 m (33 ft) sampled depending on habitat
unit size and complexity. The unit was divided into quadrants and the number of traps was
equally distributed among quadrants. Traps were placed in low-velocity areas with cover most
likely to contain fish. Traps were placed on the stream bottom, parallel to stream current. To
prevent loss, each trap was anchored to the stream bank by a tether line and flagged. Baited and
set minnow traps were soaked overnight for 18 to 24 hours. Following the overnight soak,
captured fish were identified to species, measured, and released in same site where they were
captured.
4.12.6. Snorkel Surveys
Single-pass snorkel surveys (Dolloff et al. 1993) were conducted by a three or four-person field
crew trained in snorkel survey methods and fish species identification. Climatological and
hydrological conditions, such as air and water temperatures, cloud cover, and water
clarity/visibility, were documented before beginning a survey and snorkeling was only conducted
if conditions were adequate based on Appendix 3 of the Implementation Plan. Snorkelers used a
plastic salmonid silhouette with parr marks to evaluate visibility as the horizontal underwater
distance at which the parr marks were visible. As the snorkeler approached the model, the
distance at which the parr marks on the silhouette became visible was measured. Similarly,
during retreat, the distance at which the parr marks were no longer visible was measured, and
visibility was calculated as the average of these two distances (Thurow 1994). Habitat units
were snorkeled by starting at the downstream end of the sample area and working upstream
unless water velocity precluded upstream movement. Snorkeled distance depended on the length
of the habitat unit or mesohabitat being sampled.
Snorkel surveys consisted of a single snorkeler when wetted stream widths were less than 5 m
(16.4 ft). Observations were collected by counting fish on both sides of the stream channel while
alternating from left to right counts. For streams with wetted widths greater than 5 m (16.4 ft),
the entire area of the stream was sampled by two or more snorkelers moving upstream in tandem.
Snorkelers visually identified and counted all species encountered, and fish counts were grouped
by species and size class bins estimated in 20 mm (0.8 in) increment bins (e.g., 1-20 mm, 21-40
mm, etc.). Snorkel observations were called out to a non-snorkeling team member and recorded.
For most of the snorkel surveys in this study, two experienced biologists were designated
snorkelers, while a field technician acted as a recorder. A hand-held GPS unit was used to
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record the downstream and upstream extent of the area surveyed and the location was marked on
high-resolution aerial photographs.
To facilitate comparison of relative abundance estimates from snorkel surveys with estimates
from other sampling methods (e.g., minnow trapping or electrofishing), block nets were used to
ensure a closed population within a single habitat unit and prevent fish from leaving or entering
the unit (Hillman et al. 1992). The survey length and average wetted width of the sample area
were recorded to facilitate estimation of relative fish abundance.
4.12.7. Fyke/Hoop Nets
Fyke/hoop nets were deployed to collect fish in tributaries, sloughs, and side channels with
moderate water velocity (i.e., less than 3 ft per second). After a satisfactory location was
identified at each site, the same location was used during subsequent collection periods. The
fyke nets were approximately 40 ft long and consisted of two rectangular steel frames (3 ft wide
by 2.5 ft high), and four steel hoops, all covered by 0.25-in delta stretch mesh nylon netting. A
26 ft long by 4.1 ft deep leader net made of 0.33 in delta stretch nylon netting was sometimes
attached to a center bar of the first rectangular frame (net mouth). The second rectangular frame
had two 4-in wide by 28-in high openings, one on each side of the frame’s center bar. The four
hoops followed the second frame. The throats, 4-6 inches in diameter, were located between the
second and third hoops. The net ended in a cod end bag 8 ft long with an 8-in opening at the
end, which was tied shut while the net was fishing. Each fyke/hoop net was configured with two
wings, set perpendicular to the shore, to guide the majority of water and fish to the net mouth.
Where possible, the guide nets were configured to maintain a narrow open channel along one
bank. Where the channel size or configuration did not allow an open channel to be maintained,
the area below the fyke/hoop net was checked regularly to assess whether fish were blocked and
unable to pass upstream. A live car was located at the downstream end of the fyke/hoop net
throat to hold captured fish until they were processed. The fyke/hoop net wings and live car
were checked at least once per day while fishing, to record and measure captured fish. The
locations of the fyke/hoop net sets were mapped using a hand-held GPS unit and marked on
high-resolution aerial photographs. Fyke nets were set overnight for 18 to 24 hours.
4.12.8. Hoop Traps
Hoop traps had either 4 or 7 hoops. Smaller traps consisted of four 0.25-in steel hoops with
diameters tapered from 3 ft at the entrance to 2.25 ft at the cod end. Larger traps consisted of
seven 0.25-in-thick steel hoops inside with diameters tapered from 2 ft at the entrance to 1.5 at
the cod end. Both the four- and seven-hooped traps had two necks inside and were made up of
0.25-in-diameter knotless delta mesh. Hoop traps were generally set overnight for 18 to 24 hours
depending on logistical constraints.
4.12.9. Beach Seines
Seining methodology was dependent on habitat type and the target species. Typically, speed and
coordination were an essential part of successful seining. The size and swiftness of the target
fish influenced both the length of the seine used and the speed at which it was deployed and
retrieved. In wadeable systems, smaller nets were used and deployed by hand with one end of
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the net anchored to the shore and the other end extended out from shore and then looped around
to encircle the fish as the ends were pulled in against the beach or gravel bar. Once all fish were
withdrawn from the net, the net was cleaned of all leaf litter, sticks, rocks, and other debris,
checked for damage, and reloaded for the next set. Damage to seines was repaired following
instructions in Gebhards (in Murphy and Willis 1996).
Seine nets of various sizes were available for use that ranged from 14 to 120 ft long, 3 to 6 ft
wide, and had mesh diameters that ranged from 0.125 to 1 in. The largest and smallest available
nets were 120 ft x 5 ft x 0.5 in mesh and 14 ft x 6 ft x 0.125 in mesh, respectively.
With this range in net sizes a large variety of fish and habitats were sampled; comparisons could
be made because the area sampled was noted, the net size was noted, and the nets were deep
enough to fill the water column. The location of beach seining was recorded using a hand-held
GPS unit, in addition to being marked on high-resolution aerial photographs. The area seined
was delineated using fiberglass measuring tapes and/or a marked wading rod.
4.12.10. Out-Migrant Traps
Rotary screw traps were useful for determining the timing of emigration by downstream
migrating juvenile salmonids and resident fish (Objective 2). Four rotary screw traps were
located in the Middle and Lower River (Section 4.1.3). Flow conditions permitting, traps were
fished on a cycle of 48 hours (two days and nights) on, 72 hours off throughout the ice-free
period (Figure 4.2-2). Each trap was checked at least daily. When checked, fish were removed
from the live-boxes for processing using dip and minnow nets. To reduce fish losses from the
live-box, fish refuge structures, flow deflectors, and debris separators were sometimes installed
to dissipate water velocities and reduce predation. Before fish were removed from the live-box,
floating and large submerged debris was removed.
Once removed from the live-box, fish were sorted by species and size class and placed in 5-
gallon buckets with supplemental aeration or a holding pen situated in flowing water. For
juvenile anadromous salmonids a life stage index was be used for grouping life stage classes
(alevin, fry/parr/smolt). Standard fish handling procedures (Section 4.12.12) were followed.
Any additional processing and data collection (e.g., tissue sampling, PIT tagging) was also
performed if applicable to the species, life stage, and site location. Fish were held until fully
recovered, and the time and water temperature (°C) at release was recorded.
4.12.11. Fishwheels
Fishwheels were deployed to capture anadromous salmon as part of the Adult Salmon
Escapement Study (Study 9.7). Non-salmon species collected by the fishwheels were used
opportunistically as a source of fish for tagging studies and tissue sampling. Two fishwheels
were operated in the Lower Susitna River; one on the west bank at PRM 33.4, and the second on
the east bank at PRM 34.2. In addition, two fishwheels were used on the lower Yentna River
(TRM 6). In the Middle Susitna River near Curry (PRM 123-126) three fishwheels were used to
capture adult salmon and resident fishes for radio tagging in 2013.
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4.12.12. Fish Handling
Special care was taken to ensure that all fish were handled properly and that unintended
mortalities were minimized. In general, fish were kept in cool, well-oxygenated water, and the
amount of time spent away from the river environment was minimized to the extent possible.
Strategies to minimize fish stress and mortality included the following:
1. Minimizing handling to that necessary to meet Project objectives.
2. Minimizing the time fish were held.
3. Minimizing the time fish were held in anesthetic.
4. Starting with low concentrations of anesthetic and then increasing as necessary. Fish
were anesthetized only to the point at which they could be handled easily without strain.
5. Removing smaller or more sensitive fish from anesthetic first, followed by larger, less
sensitive species.
6. Holding fish in fresh or flow-through river water during examination.
7. Using wet transfers.
8. Monitoring water temperatures and dissolved oxygen concentrations in closed systems
regularly and adjusting as necessary.
Field crews recorded the date, start and stop times, and level of effort for all sampling events, as
well as water temperature and dissolved oxygen at sampling locations. All captured or observed
fish were identified to species and life stage when possible. For juvenile anadromous salmonids,
a life stage index was used for grouping life stages (e.g., alevin, fry/parr/smolt). When possible,
resident fishes were grouped as young-of-year (0+), juvenile (typically age 1+ and 2+), and adult
(typically age 3+). Each time a gear was sampled, a random sample of 25 individuals per
species, life stage, and site were measured for fork length (FL) in mm and weighed (grams). For
species without a forked tail (e.g., sculpin and burbot), total length was measured laterally along
the mid-line from the anterior edge of the snout to the posterior edge of the tail. The remaining
fish of each species and age class were then enumerated.
For methods in which fish were observed but not captured (i.e., snorkeling, DIDSON, and
underwater video), an attempt was made to identify all fish to species. For snorkeling, fork
length of observed fish was estimated to 20-mm (0.8 in) bins of sizes. If present, observations of
poor fish condition, lesions, external tumors, or other abnormalities were noted. All juvenile
salmon, Arctic grayling, burbot, Dolly Varden, rainbow trout, and whitefish greater than 60 mm
(2.4 in) in length were scanned for PIT tags using a portable tag reader and a PIT tag was
implanted in untagged fish. Radio tags were surgically implanted in targeted fish as described in
Section 4.12.13.
4.12.13. Remote Fish Telemetry
Remote telemetry techniques included radio telemetry and PIT tags. Both of these methods were
intended to provide detailed information from relatively few individual fish. PIT tags were
surgically implanted in small fish greater than 60 mm (2.4 in); radio transmitters were surgically
implanted in adult fish of sufficient body size of selected species distributed temporally and
spatially in the Lower and Middle River. The target species to radio-tag included Arctic
grayling, burbot, Dolly Varden, longnose sucker, northern pike, lake trout, rainbow trout
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humpback whitefish, and round whitefish. Radio-tracking provided information on fine and
coarse spatial scales related to location, speed of movement, and habitat use by surveying large
areas and relocating tagged individuals during aerial surveys. PIT tags were used to document
relatively localized movements of fish as well as growth information from tagged individuals
across seasons and years. However, the “re-sighting” of PIT-tagged fish was limited to the sites
where antenna arrays were placed. To determine movement in and out of side sloughs or
tributaries required that tagged fish pass within several feet of an antenna array, thereby limiting
array use to sufficiently small water bodies. To characterize growth rates, recaptured fish were
measured.
4.12.13.1. Radio Telemetry
The primary function of the telemetry component was to track tagged fish spatially and
temporally with a combination of fixed station receivers and mobile tracking. Time/date
stamped, coded radio signals from tags implanted in fish were recorded by fixed station or
mobile positioning. All telemetry gear (tags and receivers) was provided by ATS, Inc.
(Advanced Telemetry Systems, www.atstrack.com).
The types of behavior to be characterized include the following:
• Arrival and departure timing at specific locations/positions
• Direction of travel
• Residence time at specific locations/positions
• Travel time between locations/positions
• Migratory, holding, and spawning time and locations/positions
• Movement patterns in and between habitats in relation to water conditions (e.g.,
discharge, temperature, turbidity)
Relocation data from the radio telemetry component of this study was used to characterize the
timing of use and degree of movements among macrohabitats and over periods during which the
radio tags remain active (potentially two or three years for large fish). This objective is being
achieved by the use of long-life tags (e.g., greater than one year) and shorter life tags (e.g., three-
month tags) applied to appropriate-sized fish over time. In general, successful radio telemetry
studies use a tag weight to fish weight guideline of 3 percent (with a common range of 2 to 5
percent depending on the species).
Tags were surgically implanted in fish of sufficient body size, distributed temporally and
spatially in the Lower and Middle River with a goal of 30 per-species. These fish were captured
during sampling events targeting adult fish and with directed effort using a variety of methods.
Larger tags accommodated the greatest battery life and therefore were used when fish were large
enough, but smaller, shorter life tags were used across the range of adult body sizes. Four
different-sized radio tags were used with expected operational lives ranging from 180 to 901
days. The ATS model 1810C, 1815C, 1820C, and 1830C tags have minimum tagging weights of
200, 233, 267, and 367 g, respectively. The tags used for this study were programmed to operate
in “slow pulse” mode with approximately 12 pulses-per-minute in order to extend the operational
life of the tags as much as possible. All tags were equipped with a motion sensitive sensor to
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alert biologists when a tag has remained motionless for 24 consecutive hours. Due to the number
of tags planned for release seven radio frequencies were needed for this study.
Locating radio-tagged fish was achieved by fixed receiver stations and aerial surveys. In
conjunction with the Salmon Escapement Study (Study 9.7) fixed-station receivers were operated
at nine strategic locations in the Middle and Lower River (Section 4.1.5). During the installation
of the fixed-receiver sites, a reference radio tag was used to calibrate each receiver and verify
that they were capable of detecting tags passing along the opposite river bank. Antennas were
oriented to allow for determination of a fish’s direction of migration, be it upstream,
downstream, or in some cases into a tributary.
The Salmon Escapement Study (Study 9.7) provided approximately weekly aerial survey
coverage of the study area (approximately July through October; Table 4.2-2). At other times of
the year, the frequency and location of aerial surveys was at least monthly and bi-weekly during
critical species-specific time periods (e.g., burbot spawning).
4.12.13.2. PIT Tag Antenna Arrays
Half-duplex PIT tags, either 12 or 23 mm in length, were used depending upon the size of the
fish. For increased performance and data collection, fish were tagged with the largest tag size
that their body size could carry. Each PIT tag had a unique code that allowed for identification
of individuals. The target species for PIT tagging were juvenile Chinook and coho salmon and
the following juvenile and adult fish species: Arctic grayling, Arctic lamprey, burbot, Dolly
Varden, northern pike, rainbow trout, humpback whitefish, and round whitefish.
Fish for PIT tagging were captured opportunistically during fish distribution and abundance
sampling. To increase the probability of collecting information on fish movements, fish were
captured and tagged in relatively close proximity to interrogation sites. Several arrays were
located in Focus Area study sites where increased effort was directed towards tagging fish.
PIT tag antenna arrays with automated data logging were used at selected sites to detect
movement of tagged fish into or out of off-channel habitats or tributaries habitats. Each PIT tag
interrogation system consisted of a power source, data logger, antenna and tuning capacitor. A
solar panel and controller was used to power the reader and charge the battery bank. Data
loggers were downloaded every two to four weeks, depending on the weather and water
conditions, the need to monitor power supply, and the reliability of logging systems. A total of
four stationary PIT tag interrogation systems were installed in the Middle and Lower River
(Section 4.1.4, Figure 4.2-1).
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RESULTS 5.
Objective 1: Fish Distribution, Relative Abundance, and Habitat 5.1.
Associations
5.1.1. Task A: Fish Distribution
Eighteen fish species were documented in the Middle and Lower Susitna River study area in
2013 (Table 5.1-1). These species include all five of the North American Pacific salmon species
(i.e., Chinook, chum, coho, pink, and sockeye salmon), six other salmonid species (i.e., Arctic
grayling, Dolly Varden, rainbow trout, Bering cisco, and humpback and round whitefish), and
seven non-salmonid species (i.e., burbot, lamprey, longnose sucker, northern pike, sculpin, and
ninespine and threespine stickleback). Sculpin and lamprey were not always identified to the
species level during field surveys; therefore, they are reported herein as sculpin and lamprey spp.
Furthermore, when sculpin and lamprey were identified to species, identifications were limited to
slimy sculpin and Arctic lamprey, respectively. Eight of the 18 species in the Middle and Lower
River study area were also found in the Upper Susitna River study area during 2012 and 2013
field studies (Table 5.1-1; ISR Study 9.5 Section 5.1.1). Northern pike were the only non-native
or invasive species observed in the study area.
Within the Middle River study area, Devils Canyon (i.e., MR-3 and MR-4) appeared to limit the
distribution of several species to geomorphic reaches downstream of the canyon (Table 5.1-1).
Each of the 18 species observed within the Middle and Lower River study area in 2013 was
observed downstream of the canyon, yet only seven species (i.e., Chinook salmon, Arctic
grayling, burbot, Dolly Varden, longnose sucker, sculpin, and round whitefish) were documented
in geomorphic reaches MR-1 and MR-2. Although humpback whitefish were not observed in
MR-1 or MR-2, they were documented in the Upper River study area (ISR Study 9.5 Section
5.1.1), and it is possible that the undifferentiated whitefish observations in MR-1 and MR-2
included humpback whitefish (Table 5.1-1). Five of the 11 species that were not observed
upstream of Devils Canyon were documented in each of the Middle and Lower River study area
reaches downstream of the canyon; these species include chum, coho, pink, and sockeye salmon,
and rainbow trout (Table 5.1-1). This pattern suggests that Devils Canyon influences the
distribution of these migratory species. Dolly Varden and sculpin were the only species
observed in the geomorphic reaches that include Devils Canyon (i.e., MR-3 and MR-4 (Table
5.1-1).
Additional information regarding the spatial and seasonal distribution of each of the 18
documented species is provided in the subsections that follow. Seasonal distribution patterns are
discussed relative to five distinct sampling events that occurred in 2013. These events were:
winter (February 1 to April 14), spring Early Life History (ELH) sampling (April 15 to June 30),
early summer (July 1 to August 10), late summer (August 11 to September 9), and fall
(September 10 to October 12). A more detailed analysis of seasonal movement patterns for
several of these species is provided in Section 5.2.2.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations).
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5.1.1.1. Chinook salmon
During the 2013 fish surveys in the Middle and Lower Susitna River study area, Chinook salmon
were documented in all surveyed geomorphic reaches with the exception of MR-1 and MR-4
(Table 5.1-1). The spatial distribution of adults and juveniles was similar in all reaches, except
in MR-7, where only juveniles were observed (Tables 5.1-2 and 5.1-3).
As expected for this anadromous species, the seasonal distribution of Chinook salmon differed
between the juvenile and adult life stages (Table C1). Within the geomorphic reaches where
Chinook salmon were observed, juveniles were documented during all sampling events with the
exception of the spring, late summer, and fall events in MR-2. Adult Chinook salmon were
observed seasonally in early summer and less commonly during the spring and late summer
events.
5.1.1.2. Chum salmon
Chum salmon were documented in all geomorphic reaches surveyed downstream of Devils
Canyon (Table 5.1-1). The spatial distribution of adults and juveniles was similar in all reaches,
except in MR-5 and LR-3, where only adults and juveniles were observed, respectively (Tables
5.1-2 and 5.1-3).
Similar to Chinook salmon, the seasonal distribution of chum salmon differed between the
juvenile and adult life stages (Table C2). Among the geomorphic reaches where juvenile chum
salmon were observed, juveniles were consistently documented during the spring, early summer,
and late summer events with the exception of LR-4. In this downstream-most reach of the
Middle and Lower River study area, chum salmon juveniles were only observed during the late
summer event. Juveniles were also observed during the winter sampling event in MR-8 and the
fall sampling event in LR-2. In five of the seven reaches with documented adult chum salmon
presence (i.e., MR-6, MR-8, LR-1, LR-2, and LR-4), adults were observed during the early
summer, late summer, and fall events. In MR-5, adult observations occurred only during early
summer, and in MR-7, observations were limited to the early and late summer events.
5.1.1.3. Coho salmon
As with chum salmon, coho salmon were documented in every geomorphic reach sampled
downstream of Devils Canyon (Table 5.1-1). Both juvenile and adult coho salmon were
observed in each of these reaches (Tables 5.1-2 and 5.1-3).
The seasonal distribution of coho salmon differed between the juvenile and adult life stages
(Table C3). Among the eight geomorphic reaches where coho salmon were observed, juveniles
were consistently documented during all survey events, including the winter sampling event in
MR-6 and MR-8. Adult coho salmon were observed during the late summer event in all reaches
downstream of Devils Canyon. Adults were also documented in five of these reaches during the
fall sampling event (i.e., MR-5, MR-6, MR-8, LR-1, and LR-2) and in three of the reaches
during the early summer event (i.e., MR-6, MR-7, and MR-8).
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5.1.1.4. Pink salmon
Pink salmon were also documented in every surveyed geomorphic reach downstream of Devils
Canyon (Table 5.1-1). Adults were observed in each of these reaches, whereas juveniles were
observed in only five of the eight reaches (Tables 5.1-2 and 5.1-3). Reaches where juvenile pink
salmon were documented included MR-5, MR-6, MR-7, MR-8, and LR-2.
Like other Pacific salmon species, the seasonal distribution of pink salmon differed between life
stages (Table C4). Among the geomorphic reaches where juvenile pink salmon were observed,
juveniles were most consistently observed during the early summer event. They were also
documented during spring sampling in MR-6, MR-8, and LR-2 and during winter in MR-8.
Adult pink salmon were observed in all eight reaches downstream of Devils Canyon during the
early summer event. Adults were also present in five of the eight reaches during late summer
period (i.e., MR-5, MR-6, MR-8, LR-1, and LR-2) and in a single reach during the fall sampling
event (i.e., LR-3).
5.1.1.5. Sockeye salmon
Similar to the other Pacific salmon species in the Middle and Lower River study area, sockeye
salmon were documented in all geomorphic reaches downstream of Devils Canyon (Table 5.1-1).
Juvenile sockeye salmon were found in all reaches, and adults were observed in all reaches with
the exceptions of LR-2 and LR-3 (Tables 5.1-2 and 5.1-3).
The seasonal distribution of sockeye salmon differed between life stages (Table C5). In every
geomorphic reach downstream of the canyon, juveniles were observed during all sampling
events with the exceptions of the winter event in MR-8, the late summer event in MR-5, and the
fall event in LR-2 and LR-4. Adults were most consistently observed among reaches during the
early and late summer events. Early summer observations occurred in MR-5, MR-6, MR-7, MR-
8, and LR-1, and late summer observations were made in MR-6, MR-7, MR-8, LR-1, and LR-4.
Adult sockeye salmon were also observed during the fall sampling event in MR-6, MR-8, and
LR-1.
5.1.1.6. Arctic grayling
Arctic grayling were widely distributed throughout the Middle and Lower Susitna River study
area and were present upstream and downstream of Devils Canyon (Table 5.1-1). Their spatial
distribution extended from LR-4 to MR-1, although their presence within reaches MR-3 and
MR-4 was not documented during the 2013 fish studies.
Among sampling events, the presence of Arctic grayling was largely consistent, particularly from
early summer through fall (Table C6). Prior to early summer, the distribution of Arctic grayling
was more limited. The species was not documented during winter sampling, and during the
spring event, Arctic grayling were observed in only two of the eight reaches surveyed (i.e., MR-6
and MR-8).
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5.1.1.7. Burbot
Similar to Arctic grayling, burbot were widely distributed throughout the Middle and Lower
Susitna River study area and were present upstream and downstream of Devils Canyon (Table
5.1-1). Their spatial distribution extended from LR-4 to MR-1, although their presence within
reaches MR-3 and MR-4 was not documented during the 2013 fish surveys.
The seasonal distribution of burbot was also largely similar to that observed for Arctic grayling
(Table C7). Burbot were documented in each surveyed reach during the early summer, late
summer, and fall events. They were also observed in winter in MR-8 and during the spring event
in MR-6, MR-7, and MR-8.
5.1.1.8. Dolly Varden
Dolly Varden were documented in 10 of the 11 geomorphic reaches surveyed within the Middle
and Lower River study area (Table 5.1-1). They were found in both reaches upstream of Devils
Canyon (i.e., MR-1 and MR-2), in 7 of the downstream reaches (i.e., MR-5, MR-6, MR-7, MR-
8, LR-1, LR-2, and LR-3), and in Chinook Creek (i.e., MR-4) upstream of the Zone of
Hydrologic Influence.
The presence of Dolly Varden within geomorphic reaches was largely consistent across sampling
seasons (Table C8). For example, five of the eight reaches that were surveyed during the spring,
early summer, late summer, and fall events supported Dolly Varden during each of these events;
these reaches include MR-2, MR-6, MR-7, MR-8, and LR-2. Dolly Varden were also present in
Chinook Creek (i.e., MR-4) during the early summer, late summer, and fall events. Other
observations of Dolly Varden occurred in MR-5 and LR-3 during early summer and in MR-1 and
LR-1 during late summer.
5.1.1.9. Lamprey
Within the Middle and Lower River study area, lamprey were observed only in the six
downstream-most geomorphic reaches (Table 5.1-1). These reaches include MR-7, MR-8, LR-1,
LR-2, LR-3, and LR-4.
The distribution of lamprey was largely consistent among seasons (Table C9). In MR-8, LR-1,
LR-2, LR-3, and LR-4, lamprey were observed during all sampling events except early summer
in LR-1 and LR-4. In MR-7, the opposite pattern was observed; that is, lamprey were observed
only during the early summer period.
5.1.1.10. Longnose sucker
Similar to Arctic grayling, burbot, and Dolly Varden, longnose suckers were distributed
throughout the Middle and Lower Susitna River study area and were present upstream and
downstream of Devils Canyon (Table 5.1-1). Their spatial distribution extended from LR-4 to
MR-1, although their presence within reaches MR-3 and MR-4 was not documented during the
2013 field studies.
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The distribution of longnose suckers was largely consistent among seasons (Table C10). In all
11 of the geomorphic reaches sampled in the Middle and Lower River study area, this species
was observed during all events with the exception of: the winter sampling event in MR-6 and
MR-8, the Spring event in MR-2 and LR-1, and the early summer, late summer, and fall
sampling events in Chinook Creek (i.e., MR-4).
5.1.1.11. Northern pike
Among the 18 species documented in the Middle and Lower Susitna River study area, northern
pike were the only non-native species and were the least commonly observed and most narrowly
distributed (Table 5.1-1). Their spatial distribution was limited to only the lowermost
geomorphic reach within the study area (i.e., LR-4).
The distribution of northern pike did not vary among seasons (Table C11). Northern pike were
observed in LR-4 during the spring, early summer, late summer, and fall sampling events. More
information regarding accounts of northern pike is presented in Section 5.6.
5.1.1.12. Rainbow trout
The distribution of rainbow trout in the Middle and Lower Susitna River study area was similar
to that observed for chum, coho, pink, and sockeye salmon (Table 5.1-1). Rainbow trout were
documented in all geomorphic reaches downstream of Devils Canyon yet were not observed
upstream of the canyon.
There was little variation in the seasonal distribution of rainbow trout (Table C12). The species
was observed during the majority of sampling events in reaches downstream of Devils Canyon.
Exceptions included winter sampling in MR-6, spring sampling in LR-1 and LR-4, late summer
sampling in MR-5, LR-3, LR-4, and fall sampling in LR-1 and LR-4.
5.1.1.13. Sculpin
Similar to Arctic grayling, burbot, Dolly Varden, and longnose suckers, sculpin were distributed
throughout the Middle and Lower Susitna River study area and were present upstream and
downstream of Devils Canyon (Table 5.1-1). Their spatial distribution extended from LR-4 to
MR-1, although their presence within reaches MR-3 and MR-4 was limited to Chinook Creek.
The distribution of sculpin was almost entirely consistent among seasons (Table C13). In all 11
of the geomorphic reaches sampled in the Middle and Lower River study area, sculpin were
observed during all sampling events except for late summer in Chinook Creek (MR-4).
5.1.1.14. Ninespine stickleback
Similar to northern pike, the presence of ninespine stickleback was limited to the Lower River
(Table 5.1-1). Their spatial distribution extended from LR-4 to LR-1.
The distribution of ninespine stickleback varied somewhat among seasons (Table C14).
Ninespine stickleback were most common during the early summer event when they observed in
all four of the Lower River reaches within the study area. They were also present during the
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spring event in LR-2 and LR-3, during late summer in LR-1, LR-3, and LR-4, and during fall in
LR-3 and LR-4.
5.1.1.15. Threespine stickleback
The distribution of threespine stickleback in the Middle and Lower Susitna River study area was
similar to that observed for chum, coho, pink, and sockeye salmon and rainbow trout (Table 5.1-
1). The main difference between the distribution of threespine stickleback and these other
species is that threespine stickleback were documented in LR-4 through MR-5, whereas the other
species were documented in LR-4 through MR-6.
There was little variation in the seasonal distribution of threespine stickleback (Table C15). The
species was observed during all sampling events in MR-7, MR-8, LR-1, LR-2, LR-3, and LR-4.
In MR-6, observations occurred only during early and late summer.
5.1.1.16. Bering cisco
Similar to northern pike and ninespine stickleback, Bering cisco were limited to the Lower River
(Table 5.1-1). Their spatial distribution included LR-2 and LR-4.
The distribution of Bering cisco appears to have varied among seasons (Table C16). All Bering
cisco observations occurred during the fall sampling event. However, the observed seasonal
pattern should be viewed with caution due to the relatively few Bering cisco observations in the
study area.
5.1.1.17. Humpback whitefish
The distribution of humpback whitefish differs from other species encountered in the Middle and
Lower Susitna River study area in that it was observed primarily in the Middle River (Table 5.1-
1). The species was observed in all four Middle River geomorphic reaches downstream of
Devils Canyon (i.e., MR-5, MR-6, MR-7, and MR-8) as well as a single reach in the Lower
River (i.e., LR-4). As noted earlier, it is possible that humpback whitefish were also present
upstream of Devils Canyon in MR-1 and MR-2, given the presence of undifferentiated whitefish
species in these reaches (Table 5.1-1).
The distribution on humpback whitefish was variable on a seasonal basis (Table C17). They
were most commonly observed during the spring and early summer sampling events in the
Middle River geomorphic reaches. Late summer observations were made in MR-6 and MR-8,
and all observations in the Lower River occurred during the fall sampling event in LR-4.
5.1.1.18. Round whitefish
Similar to Arctic grayling, burbot, Dolly Varden, longnose suckers, and sculpin, round whitefish
were widely distributed throughout the Middle and Lower Susitna River study area and were
present upstream and downstream of Devils Canyon (Table 5.1-1). Their spatial distribution
extended from LR-4 to MR-1, although their presence within reaches MR-3 and MR-4 was not
documented during the 2013 fish distribution and abundance study.
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The distribution of round whitefish was largely consistent among sampling events although some
variation in seasonal distribution was observed (Table C18). Round whitefish were present in
each geomorphic reach surveyed during the late summer and fall sampling events. A nearly
identical pattern was observed for the early summer event, although the species was not detected
in MR-1 or LR-4 during this season. Occurrences during the spring sampling event were less
common but still included five of the eight geomorphic reaches surveyed during this time period
(i.e., MR-6, MR-8, LR-1, LR-3, and LR-4). Round whitefish were also observed during winter
sampling in MR-8.
5.1.2. Task B: Relative Abundance
5.1.2.1. Middle River
Fish observations from all fish sampling efforts in the Middle River combined totaled 45,899
fish (Table 5.1-2). While this provides a relative scale of the study program, only a subset of this
larger dataset, that portion collected during systematic fish distribution and abundance sampling,
was suited to calculating catch-per-unit-effort (CPUE) for comparable estimates of fish relative
abundance. The fish counts that were used to calculate CPUE are summarized for fish
distribution and abundance sampling within (Table 5.1-4) and outside (Table 5.1-5) Middle
River Focus Areas. The majority of fish observations were made when sampling with five gear
types within and three gear types outside of Focus Areas.
Total fish observations and relative abundance, as determined by CPUE analysis, are presented
by species below. CPUE was calculated to be species- and gear-specific using catch data from
distribution and abundance sampling as described in Section 4.4.2.1 and was averaged across
mesohabitats within a macrohabitat for discussing relative abundance. The CPUE analysis also
distinguished between adult and juvenile Pacific salmon, although adult salmon observations
during the Fish Distribution and Abundance surveys were considered to be incidental based on
study objectives and sampling design. Middle River CPUE summaries and tables of CPUE by
gear type are presented in Appendix E.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations, and
ISR_9_6_FDAML_FishCPUEData).
5.1.2.1.1. Adult Chinook Salmon
During 2013, 52 adult Chinook salmon were observed during all sampling in the Middle River
(Table 5.1-2). The majority of observations of adult Chinook salmon occurred incidentally while
snorkeling; they were absent from 99 percent of the sites sampled in the Middle River (Table
E1). The highest average CPUE was 6.8 fish per 1,000 m2 in tributary run habitat within MR-6
(Table E11).
5.1.2.1.2. Juvenile Chinook Salmon
During 2013, 3,300 juvenile Chinook salmon were observed during all sampling in the Middle
River (Table 5.1-2). Averaged CPUE for juvenile Chinook salmon was generally low to
moderate across sampling locations and methods, although a few notably high estimates were
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observed (Tables E9 through E14). Averages ranged from 0, at 84 percent of sites, to 351.1 fish
per 1,000 m2 in glide habitat within MR-8 upland slough habitat (Table E11). This high CPUE
was obtained by seining in early summer. Seining at the same upland slough in late summer also
produced a high average CPUE of 130.5 fish per 1,000 m2 (Table E10). In general, Middle
River CPUE averages for juvenile Chinook salmon were similar in magnitude to estimates of
CPUE for Upper and Lower River sites. The CPUE data indicated that snorkeling, seining,
backpack electrofishing, and fyke netting were effective capture techniques for juvenile Chinook
salmon (Table E1).
5.1.2.1.3. Adult Chum Salmon
During 2013, 898 adult chum salmon were observed during all sampling in the Middle River
(Table 5.1-2). Adult chum salmon were absent from 94 percent of the CPUE sites in the Middle
River (Table E1) Where they were found, the majority of adult chum salmon observations
occurred while snorkeling. The greatest average CPUE was 183.3 fish per 1,000 m2 in run
habitat associated with the Indian River tributary mouth in MR-6 (Table E17).
5.1.2.1.4. Juvenile Chum Salmon
During 2013, 1,394 juvenile chum salmon were observed during all sampling in the Middle
River (Table 5.1-2). Averaged CPUE was variable among habitats (Tables E15 to E17) and
across sampling events. CPUE ranged from 0 at 98 percent of sites (Table E1) to 104.3 fish per
1,000 m2 in tributary mouth glide habitat in MR-6 (Table E17). This maximum CPUE was in
the same tributary mouth (Indian River) where the greatest abundance of adults was observed.
Juvenile chum salmon CPUE values were higher and more frequent across all habitats in early
and late summer sampling as compared to fall. Effective gear types for capturing juvenile chum
salmon included seining, backpack electrofishing, and snorkeling (Table E1).
5.1.2.1.5. Adult Coho Salmon
During 2013, 554 adult coho salmon were observed during all sampling in the Middle River
(Table 5.1-2). Similar to other Pacific salmonid adults, the majority of observations of adult
coho salmon during systematic fish distribution and abundance sampling occurred incidentally
while snorkeling. Adult coho salmon were absent from 97 percent of the sites sampled in the
Middle River (Table E1). The greatest average CPUE was 52.7 fish per 1,000 m2 in pool habitat
within MR-8 tributary habitat (Table E23).
5.1.2.1.6. Juvenile Coho Salmon
Juvenile coho salmon were the most frequently observed species in the Middle River in 2013; a
total of 8,738 juvenile coho salmon were observed during all sampling (Table 5.1-2). Averaged
CPUE was highly variable among habitats (Tables E20 to E26) and ranged from 0 at 73 percent
of sites (Table E1) to 4,553.8 fish per 1,000 m2 in run habitat located within MR-7 upland slough
habitat in Focus Areas (Table E22). At several sites, CPUE was greater than 1,000 fish per
1,000 m2 (Tables E22 and E23). These high CPUE values occurred only during early summer
sampling. All methods except for hoop traps were effective for capturing juvenile coho salmon.
(Table E1).
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5.1.2.1.7. Adult Pink Salmon
During 2013, 4,683 adult pink salmon were observed during all sampling in the Middle River
(Table 5.1-2). Similar to other Pacific salmonid adults, the majority of observations of adult pink
salmon during systematic fish distribution and abundance sampling occurred incidentally while
snorkeling. Adult pink salmon were absent from 95 percent of the sites sampled in the Middle
River (Table E1). The greatest average CPUE values occurred during snorkeling in the Indian
River in early summer. Specifically, CPUE averages of 4,553.8 and 1,113.3 fish per 1,000 m2
were observed in pool and glide mesohabitats, respectively, within this tributary located in MR-6
(Table E30).
5.1.2.1.8. Juvenile Pink Salmon
During 2013, 427 juvenile pink salmon were observed during all sampling in the Middle River
(Table 5.1-2). The average CPUE was 0 at greater than 99 percent of sites (Table E1). For the
CPUE analysis, juvenile pink salmon were detected only during early summer sampling at two
sites. Boat electrofishing within a mainstem backwater pool in MR-7 yielded an average CPUE
of 12.5 fish per hour (Table E28), and backpack electrofishing within a side slough glide in MR-
5 yielded a catch of 1.6 fish per hour (Table E27). Both of these sites were located outside of
Focus Areas.
5.1.2.1.9. Adult Sockeye Salmon
During 2013, 236 adult sockeye salmon were observed during all sampling in the Middle River
(Table 5.1-2). The majority of these observations of adult sockeye salmon during systematic fish
distribution and abundance sampling occurred while snorkeling. Averaged CPUE for sockeye
salmon adults was 0 in 98 percent of the sites (Table E1). The greatest average CPUE was 14.7
fish per 1,000 m2 in run habitat within MR-6 side sloughs in Focus Areas (Table E35).
5.1.2.1.10. Juvenile Sockeye Salmon
During 2013, 2,594 juvenile sockeye salmon were observed during all sampling in the Middle
River (Table 5.1-2). Averaged CPUE for juvenile sockeye salmon was highly variable among
habitats (Tables E32 to E37). Averaged CPUE ranged from 0 at 86 percent of sites (Table E1) to
948.8 fish per 1,000 m2 in tributary pool habitat in MR-6 Focus Areas (Table E34). Although
two tributary pool habitats were seined during early summer in MR-6 Focus Areas (Table E4),
all of the juvenile sockeye salmon observations occurred in a single tributary (Indian River).
This site was also the location with the highest CPUE for juvenile coho salmon. Sockeye salmon
CPUE was similar across sampling events. Compared to the Lower River, average CPUE values
for the Middle River were an order of magnitude higher. Effective gear types included seining,
snorkeling, fyke netting, and backpack and boat electrofishing (Table E1).
5.1.2.1.11. Arctic Grayling
During 2013, 2,665 Arctic grayling were observed during all sampling in the Middle River
(Table 5.1-2). Averaged CPUE for Arctic grayling was highly variable among habitats and
ranged from 0 at 75 percent of sites to 378.1 fish per 1,000 m2 in clearwater plume habitat within
MR-2 Focus Areas (Table E40). Generally, averaged CPUE values in the Middle River were an
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order of magnitude lower than in the Upper River and an order of magnitude greater than in the
Lower River. CPUE data indicated that seining, backpack electrofishing, boat electrofishing,
snorkeling, and fyke netting were effective capture techniques (Table E1).
5.1.2.1.12. Burbot
During 2013, 472 burbot were observed during all sampling in the Middle River (Table 5.1-2).
Averaged CPUE for burbot was low to moderate across sampling locations and methods (Tables
E45 to E50). In the Middle River, burbot CPUE was 0 at 78 percent of sites (Table E1), and
averaged CPUE ranged from 0 to a maximum of 18.5 fish per trap in beaver pond habitat located
within MR-6 upland sloughs in Focus Areas (Table E48). It is interesting to note that burbot
CPUE values were similar among all Middle River geomorphic reaches, including those
upstream of Devils Canyon (i.e., MR-1 and MR-2), and similar to those calculated for Upper
River and Lower River habitats. The CPUE data indicated that backpack and boat electrofishing,
fyke netting, and seining were effective capture techniques for burbot (Table E1).
5.1.2.1.13. Dolly Varden
During 2013, 574 Dolly Varden were observed during all sampling in the Middle River (Table
5.1-2). Averaged CPUE for Dolly Varden in the Middle River was highly variable across
sampling locations and methods (Table E51 to E57). In the Middle River, Dolly Varden were
observed at 9 percent of sampling sites (Table E1), and averaged CPUE ranged from 0 to 243.5
fish per 1,000 m2 in tributary mouth glide habitat in MR-6 (Table E54). Averaged CPUE values
for the Middle River were of similar magnitude to those in the Upper River, yet they were much
higher than those observed in the Lower River, where the maximum average CPUE was 4.3 fish
per hour (Table E152). The CPUE data indicated that snorkeling and backpack electrofishing
were effective capture techniques for Dolly Varden (Table E1).
5.1.2.1.14. Lamprey
During 2013, 79 lamprey were observed during all sampling in the Middle River (Table 5.1-2).
In the Middle River, lamprey COUE was 0 at 98 percent of sites (Table E1), and systematic fish
distribution and abundance sampling only observed lamprey in MR-7 and MR-8. Averaged
CPUE ranged from 0 to 39.1 fish per hour in riffle habitat within side sloughs in the MR-8 Focus
Areas (Table E58). Similar CPUE values for lamprey were observed between the Middle and
Lower River. Backpack electrofishing was the most effective capture techniques for lamprey
(Table E1).
5.1.2.1.15. Longnose Sucker
During 2013, 2,059 longnose sucker were observed during all sampling in the Middle River
(Table 5.1-2). Averaged CPUE ranged from 0 at 72 percent of sites to 328.8 fish per hour in side
slough riffle habitat within MR-8 (Table E62). The values were low to moderate in all
geomorphic reaches except for MR-8 where several averaged CPUE values were an order of
magnitude greater than those observed elsewhere in the Middle River. Low to moderate values
were also observed in the Upper and Lower River. CPUE data indicated that backpack
electrofishing, seining, snorkeling, boat electrofishing, and fyke netting were effective capture
techniques (Table E1).
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5.1.2.1.16. Sculpin
Sculpin were the third most abundant species group in the 2013 Middle River fish sampling with
5,789 sculpin observed (Table 5.1-2). Sculpin were also observed at more sites than any other
species in the Middle River. Averaged CPUE was highly variable and ranged from 0 at 34
percent of sites to 569.3 fish per 1,000 m2 in tributary pool habitat within MR-6 Focus Areas
(Table E71). A similar range of relative abundance was observed for sculpin in the Upper and
Lower River. CPUE data indicated that all methods except hoop traps were effective capture
techniques (Table E1).
5.1.2.1.17. Lake Trout
Lake trout were not observed in the Middle River during 2013 sampling.
5.1.2.1.18. Ninespine Stickleback
Ninespine stickleback were not observed in the Middle River during 2013 sampling.
5.1.2.1.19. Threespine Stickleback
Threespine stickleback were the second most abundant species in the 2013 Middle River fish
sampling with 7,604 fish observed (Table 5.1-2). Similar to the Lower River, averaged CPUE
for threespine stickleback in the Middle River was generally low to moderate, and ranged from 0
at 89 percent of sites to 503 fish per trap in upland slough beaver pond habitat within MR-7
Focus Areas in late summer (Table E79). The CPUE data indicated a trend for lower averaged
values in fall as compared to early and late summer. Effective capture techniques included
backpack electrofishing, fyke nets, seining, and minnow traps (Table E1).
5.1.2.1.20. Rainbow Trout
During 2013, 457 rainbow trout were observed during all sampling in the Middle River (Table
5.1-2). Averaged CPUE was low to moderate, ranged from 0 at 91 percent of sites to 38 fish per
trap in tributary pool habitat within the Focus Area in MR-8 (Table E85), and varied among
habitats. Rainbow trout were overall more abundant in the Middle River as compared to the
Lower River. CPUE data indicated that snorkeling, fyke nets, and backpack and boat
electrofishing were effective capture techniques for rainbow trout (Table E1).
5.1.2.1.21. Bering Cisco
No Bering cisco were observed during Middle River fish distribution and abundance sampling in
2013.
5.1.2.1.22. Humpback Whitefish
During 2013, 165 humpback whitefish were observed during all sampling in the Middle River
(Table 5.1-2). Averaged CPUE was generally low and ranged from 0 at 99 percent of sites to
33.6 fish per 1,000 m2 in backwater pool habitat within the Focus Area in MR-8 (Table E89).
Humpback whitefish were overall more abundant in the Middle River as compared to the Lower
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River. CPUE data indicated that seining and boat electrofishing were effective capture
techniques for humpback whitefish (Table E1).
5.1.2.1.23. Round Whitefish
During 2013, 643 round whitefish were observed during all sampling in the Middle River (Table
5.1-2). Averaged CPUE was generally low to moderate and ranged from 0 at 83 percent of sites
to 249.5 fish per 1,000 m2 in backwater pool habitat within MR-7 Focus Areas (Table E93).
Middle River averaged CPUE values for round whitefish were generally similar to those in the
Upper and Lower River, although the observed maximum in the Middle River was a magnitude
greater than the Upper and Lower River maxima, as well as most CPUE averages in the Middle
River. CPUE data indicated that seining, boat and backpack electrofishing, snorkeling, and fyke
nets were effective capture techniques for round whitefish (Table E1).
5.1.2.2. Lower River
During 2013 all Lower River fish sampling, a total of 8,649 fish were captured or observed
(Table 5.1-3). Table 5.1-6 lists total counts for relative abundance sampling for all three
sampling events for which CPUE was estimated. Minnow traps, seines and hoop traps accounted
for 84 percent of the total Lower River catch (Table 5.1-6).
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations, and
ISR_9_6_FDAML_FishCPUEData).
5.1.2.2.1. Adult Chinook Salmon
During 2013, seven adult Chinook salmon were observed during all sampling in the Lower River
(Table 5.1-3). The averaged CPUE was 0 at 98 percent of the sites sampled in the Lower River
(Table E1). The greatest average CPUE was 2.5 fish per 1,000 m2 in tributary glide habitat
within LR-1 (Table E115).
5.1.2.2.2. Juvenile Chinook Salmon
During 2013, 1,655 juvenile Chinook salmon were observed during all sampling in the Lower
River (Table 5.1-3). Average CPUE values were low to moderate and ranged from 0 at 74
percent of sites to 43.7 fish per hour in clearwater plume habitat in LR-3 (Table E112).
Averaged CPUE values were greater in LR-1 and LR-3 than in LR-2 and LR-4 (Tables E112 to
E114 and E116 to E118). In general, Lower River CPUE averages for juvenile Chinook salmon
were similar in magnitude to estimates of CPUE for Upper and Middle River sites. Fyke nets,
hoop traps, seining, and backpack and boat electrofishing were effective capture techniques for
juvenile Chinook salmon in the Lower River (Table E1).
5.1.2.2.3. Adult Chum Salmon
During 2013, 304 adult chum salmon were observed in the Lower River (Table 5.1-3). Averaged
CPUE was 0 at 94 percent of the sites sampled (Table E1). The highest average CPUE was 25
fish per 1,000 m2 in clearwater plume habitat in LR-1 (Table E121).
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5.1.2.2.4. Juvenile Chum Salmon
During 2013, 877 juvenile chum salmon were observed during all sampling in the Lower River
(Table 5.1-3). Overall, averaged CPUE values were low to moderate (Tables E119 to E120 and
E122 to E124) and ranged from 0 at 92 percent of sites (Table E1) to 16 fish per 1,000 m2 in side
slough pool habitat in LR-1 (Table E120). In contrast to the Middle River, juvenile chum
salmon CPUE did not appear to vary across seasonal sampling events in the Lower River.
Effective gear types for capturing juvenile chum salmon included seining and backpack
electrofishing (Table E1).
5.1.2.2.5. Adult Coho Salmon
During 2013, 72 adult coho salmon were observed during all sampling in the Lower River (Table
5.1-3). Adult coho salmon averaged CPUE was 0 for 95 percent of the Lower River sites (Table
E1). Similar to adult chum salmon, the highest average CPUE was 62.5 fish per 1,000 m2 in
clearwater plume habitat in LR-1 (Table E127).
5.1.2.2.6. Juvenile Coho Salmon
During 2013, 607 juvenile coho salmon were observed during all sampling in the Lower River
(Table 5.1-3). Overall, averaged CPUE values were low to moderate (Tables E125, E126, and
E128 to E130) and ranged from 0 at 76 percent of sites (Table E1) to 45 fish per trap (Tables
E128 and E129). This maximum was observed on two occasions, once in late summer within
upland slough glide habitat (Table E128) and once during fall sampling in upland slough beaver
pond habitat (Table E129). In general, the averaged CPUE for juvenile coho salmon was
substantially less than that observed for this species and life stage in the Middle River. Effective
gear types for juvenile coho salmon included hoop traps, fyke nets, backpack electrofishing, and
seining (Table E1).
5.1.2.2.7. Adult Pink Salmon
During 2013, 422 adult pink salmon were observed during all sampling in the Lower River
(Table 5.1-3). Averaged CPUE ranged from 0 at 94 percent of sites (Table E1) to 15 fish per
1,000 m2 in tributary glide habitat in LR-2 (Table E132).
5.1.2.2.8. Juvenile Pink Salmon
During 2013, only six juvenile pink salmon were observed during all sampling in the Lower
River (Table 5.1-3). All of these observations were associated with downstream migrant
trapping in Montana Creek. Thus, there are no data available to estimate CPUE for juvenile pink
salmon in the Lower River.
5.1.2.2.9. Adult Sockeye Salmon
During 2013, seven adult sockeye salmon were observed during all sampling in the Lower River
(Table 5.1-3). Averaged CPUE ranged from 0 at 97 percent of sites (Table E1) to 1.7 fish per
1,000 m2 in side channel complex run habitat in LR-2 (Table E136).
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5.1.2.2.10. Juvenile Sockeye Salmon
During 2013, 444 juvenile sockeye salmon were observed during all sampling in the Lower
River (Table 5.1-3). Averaged CPUE for juvenile sockeye salmon was highly variable among
habitats (Tables E135, E136, E138-E140). Averages ranged from 0 at 77 percent of sites (Table
E1) to 280 fish per 1,000 m2 in side slough run habitat within LR-1 (Table E136). Compared to
the Middle River, average CPUE values for the Lower River were an order of magnitude lower.
Effective gear types included seining, backpack electrofishing, and fyke netting (Table E1).
5.1.2.2.11. Arctic Grayling
During 2013, 39 Arctic grayling were observed during all sampling in the Lower River (Table
5.1-3). Averaged CPUE for Arctic grayling was generally low, particularly when compared to
the Upper and Middle River segments. Values ranged from 0 at 87 percent of sites to 8.6 fish
per hour in side channel run habitat within LR-4 (Table E142). CPUE data indicated backpack
and boat electrofishing, and in some cases, seining were effective capture techniques (Table E1).
5.1.2.2.12. Burbot
During 2013, 154 burbot were observed during all sampling in the Lower River (Table 5.1-3).
Similar to the Upper and Middle River, averaged CPUE for burbot was low to moderate across
sampling locations and methods (Table E146 to E151). Averaged CPUE ranged from 0 to 23.8
fish per hour in side slough run habitat within LR-4 (Table E147). The CPUE data indicated that
backpack and boat electrofishing, fyke nets, hoop traps, and seining were effective capture
techniques for burbot (Table E1).
5.1.2.2.13. Dolly Varden
During 2013, 30 Dolly Varden were observed during all sampling in the Lower River (Table 5.1-
3). Averaged CPUE values for Dolly Varden in the Lower River was low and ranged from 0 at
96 percent of sampling sites (Table E1) to 4.3 fish per hour in side channel complex riffle habitat
in LR-1 (Table E152). Averaged CPUE values for the Lower River were two orders of a
magnitude less than those in the Middle and Upper River. Effective gear types included
backpack electrofishing, seining, and fyke nets (Table E1).
5.1.2.2.14. Lamprey
During 2013, 133 lamprey were observed during all sampling in the Lower River (Table 5.1-3).
Averaged CPUE was low to moderate and varied among habitats and geomorphic reaches and
ranged from 0 at 81 percent of sites to 28.6 fish per hour in clearwater plume habitat within LR-3
(Table E155). Similar CPUE values for lamprey were observed between the Lower and Middle
River. Backpack and boat electrofishing were the most effective capture techniques for lamprey
in the Lower River (Table E1).
5.1.2.2.15. Longnose Sucker
During 2013, 1,115 longnose suckers were observed during all sampling in the Lower River
(Table 5.1-3). Averaged CPUE ranged from 0 at 37 percent of sites to 188 fish per trap in
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upland slough run habitat within LR-4 (Table E163). When longnose suckers were detected,
averaged CPUE values were generally moderate. These values tended to be slightly less than
and slightly greater than those in the Middle and Upper River, respectively. CPUE data
indicated that backpack and boat electrofishing, seining, hoop traps, and fyke nets were effective
capture techniques (Table E1).
5.1.2.2.16. Northern Pike
During 2013, 62 northern pike were observed during all sampling in the Lower River (Table 5.1-
3). Averaged CPUE ranged from 0 at 97 percent of sites to 40 fish per 1,000 m2 in tributary
glide habitat within LR-4 (Table E169). During Lower River transect sampling, northern pike
were found only during early and late summer in LR-4. They were not detected in LR-1, LR-2,
or LR -3. Effective gear types included backpack and boat electrofishing, seining, snorkeling,
and minnow traps (Table E1).
5.1.2.2.17. Sculpin
During 2013, 897 sculpin were observed during all sampling in the Lower River (Table 5.1-3).
Similar to the Middle and Upper River, sculpin were detected at more sites than any other
species in the Lower River, and averaged CPUE was highly variable among geomorphic reaches
and sampling events. Values ranged from 0 at 37 percent of sites to 1,009.8 fish per hour in
clearwater plumes within LR-2 (Table E171). CPUE data indicated that backpack electrofishing,
seining, and hoop traps were effective capture techniques (Table E1).
5.1.2.2.18. Lake Trout
Lake trout were not observed in the Lower River during 2013 sampling.
5.1.2.2.19. Ninespine Stickleback
During 2013, 144 ninespine stickleback were observed during all sampling in the Lower River
(Table 5.1-3). Averaged CPUE for ninespine stickleback in the Lower River was generally low
and ranged from 0 at 89 percent of sites to 34 fish per 1,000 m2 in pool habitat within LR-3
additional open water habitat (Table E177). Catch per unit effort was consistently low in LR-1,
and the species was not detected in LR-2. Effective capture techniques included backpack
electrofishing, fyke nets, and seining (Table E1).
5.1.2.2.20. Threespine Stickleback
Threespine stickleback were the most abundant species in the 2013 Lower River fish sampling
with 4,469 fish observed (Table 5.1-3). Similar to the Middle River, averaged CPUE for
threespine stickleback in the Lower River was generally low to moderate; but in the Lower River
this species was more frequently present. Averaged CPUE ranged from 0 at 66 percent of sites
to 495 fish per trap in upland slough beaver pond habitat within LR-3 (Table E185). Threespine
stickleback CPUE varied across Lower River geomorphic reaches, with lower observed averages
in LR-1 and LR-2 compared to LR-3 and LR-4. Effective capture techniques included backpack
electrofishing, fyke nets, seining, and hoop traps (Table E1).
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5.1.2.2.21. Rainbow Trout
During 2013, 165 rainbow trout were observed during all sampling in the Lower River (Table
5.1-3). Averaged CPUE ranged from 0 at 93 percent of sites to 25.9 fish per hour in upland
slough backwater habitat within LR-4 (Table E187). Low CPUE values were observed in LR-1
and LR-2, whereas those observed in LR3 and LR-4 were low to moderate. These Lower River
CPUEs were generally similar between to those calculated for the Middle River. Backpack
electrofishing was the most effective capture techniques for rainbow trout in the Lower River
(Table E1).
5.1.2.2.22. Bering Cisco
During 2013, only two Bering cisco were observed during all sampling in the Lower River
(Table 5.1-3). Averaged CPUE was generally low and ranged from 0 at 98 percent of sites to 4.3
fish per hour in side slough run habitat within LR-4. Bering cisco were not detected in any other
geomorphic reach (Table E192). CPUE data indicated that backpack and boat electrofishing
were effective capture techniques for Bering cisco (Table E1).
5.1.2.2.23. Humpback Whitefish
During 2013, eight humpback whitefish were observed during all sampling in the Lower River
(Table 5.1-3). Similar to Bering cisco, averaged CPUE was generally low, and humpback
whitefish were detected only in LR-4. Average CPUE values ranged from 0 at 98 percent of
sites to 14.7 fish per hour side slough run habitat (Table E193). Lower River humpback
whitefish CPUE values were similar to those calculated for the Middle River. CPUE data
indicated that seining and boat electrofishing were effective capture techniques for humpback
whitefish (Table E1).
5.1.2.2.24. Round Whitefish
During 2013, 112 round whitefish were observed during all sampling in the Lower River (Table
5.1-3). Averaged CPUE was generally low to moderate in each Lower River geomorphic reach
and ranged from 0 at 77 percent of sites to 12.9 fish per hour in clearwater plumes within LR-1
(Table E196). Lower River averaged CPUE values for round whitefish were generally similar to
those in the Upper and Middle River, although the observed maxima in the Lower and Upper
River were a magnitude less than the Middle River maximum. CPUE data indicated that seining
and boat and backpack electrofishing were effective capture techniques for round whitefish
(Table E1).
5.1.3. Task C: Habitat Associations
Because 2013 data QA/QC and analysis is ongoing, fish observation data were used to provide a
preliminary look at fish-habitat associations in the Middle and Lower River.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations).
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5.1.3.1. Middle River
Combining counts from available data sources, a total of 45,889 fish observations were made in
the Middle River. This includes observation from three direct sample Middle River tributaries
above Devils Canyon and six mainstem Middle Susitna River geomorphic reaches (Table 5.1-2)
during four sampling events. The highest total counts of fish were obtained in off-channel
habitats in MR-7, largely driven by high numbers of threespine stickleback documented during
distribution and relative abundance sampling (Tables F1, F2, F43, F44). High fish counts,
including juvenile salmon, were obtained in off-channel and tributary habitats in MR-6 and the
mainstem Susitna River in MR-8 (Table 5.1-2). In general, more fish were observed in off-
channel habitats and tributaries than in the mainstem reaches. More fish were also observed
inside of Focus Areas (Table F1) than outside of Focus Areas (Table F2).
To begin to understand species-specific patterns in habitat use, species counts are presented by
mesohabitat unit and sampling event in Appendix F for the Middle River (Tables F4 to F52) and
Lower River Tables (F54 to F80). The following general patterns are evident from this early
data.
• Adult Chinook salmon were observed primarily in early summer and were associated
with riffle and run mesohabitats within clearwater plume, tributary, and tributary mouth
macrohabitats (Tables F3 and F4). Most adult Chinook salmon observed in the Middle River
were associated with spawning tributaries: Tsusensa Creek, Portage Creek, and Indian River.
Counts overall were low overall (22) and were not different inside and outside of Focus Areas
(Tables F3 and F4)
• Juvenile Chinook salmon were found in much higher numbers inside of Focus Areas
(Table F5) than outside of Focus Areas (Table F6). Juvenile Chinook were observed during all
seasons in a variety of habitats including tributaries, the main channel Susitna River, and off-
channel Susitna River. Among macrohabitat types, juvenile Chinook counts were highest in
upland slough beaver complexes, tributaries, and side channels. Among mesohabitats, counts
were highest in slow water habitats, e.g. beaver ponds, glides, and pools (Table F5).
• Adult chum salmon were primarily observed in early to late summer with similar
numbers inside and outside of Focus Areas (Tables F7 and F8). Adult chum were observed in a
variety of habitats including tributaries, the main channel Susitna River, and off-channel Susitna
River. The highest counts of chum salmon were in glide habitat in spawning tributaries and side
sloughs in MR-5 and MR-6 (Tables F7 and F8).
• Juvenile chum salmon were primarily observed during the spring Early Life History
sampling inside of Focus Areas in MR-6 (Tables F9 and F10). Counts were highest in run and
beaver pond mesohabitats within the Slough 11 side slough beaver complex in MR-6.
• Adult coho salmon were primarily observed during the late summer in MR-7 and MR-8
(Tables F11 and F12). The highest counts of adult coho salmon were in glide, run, and pool
habitats in spawning tributaries and side sloughs (Tables F11 and F12). Counts were more than
twice as high inside of Focus Areas (Table F11) as compared to outside Focus Areas (Table
F12).
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• Juvenile coho salmon were observed in all seasons with higher counts inside of Focus
Areas (Table F13) as compared to outside Focus Areas (Table F14). Observations were
primarily made in tributary and off-channel habitats in MR-6, 7, and 8. Counts were highest in
slow water (e.g. pool and beaver pond) mesohabitats within side slough and upland slough
beaver complexes (Tables F13 and F14).
• Adult pink salmon were observed primarily in early summer with higher counts inside of
Focus Areas (Table F15) as compared to outside Focus Areas (Table F16). This pattern was
driven by large numbers of fish observed in FA-141 (Indian River). Counts were highest in pool,
run, and glide mesohabitats in spawning tributaries with lower counts associated with clearwater
plumes (Tables F15 and F16).
• Juvenile pink salmon were observed in lower numbers in the spring and early summer
(Table F17 and F18). Observations were made in a variety tributary, main channel Susitna, and
off-channel Susitna habitats. Counts were similar inside and outside of Focus Areas.
• Adult sockeye salmon were primarily observed in late summer and fall in MR-6 (Tables
F19 and F20). Counts were highest in beaver pond and glide mesohabitats in upland sloughs and
side sloughs (Tables F19 and F20). Counts were more than twice as high outside of Focus Area
as compared to inside Focus Areas.
• Juvenile sockeye salmon were mostly observed in spring and early summer with higher
numbers inside of Focus Areas (Table F21) as compared to outside Focus Areas (Table F22).
Most observations were made in tributary and off-channel habitats in MR-6 (Table F21). Counts
were highest in slow water (e.g. glide and pool) mesohabitats within side sloughs with and
without beaver complexes (Tables F21 and F22).
• Juvenile salmon that could not be identified to species were observed during all seasons
with higher counts inside of Focus Areas (Tables F23 and F24). Most of these observations were
made in one upland slough beaver complex in MR-7 where identification of salmon parr was
particularly challenging as individual fish displayed multiple characteristics of more than one
salmon species (Table F23).
• Arctic grayling were observed in all seasons in a variety of habitats including tributaries,
the main channel Susitna River, and off-channel Susitna River (Tables F25 and F26). Counts
were more than twice as high inside of Focus Areas (Table F25) as compared to outside Focus
Areas (Table F26). Juvenile Arctic graying counts were highest in MR-2 in slow water
mesohabitat types, e.g. pools and backwaters associated with side sloughs and clearwater plumes
(Tables F27 and F28). Similar to juveniles, adult Arctic grayling were observed within
clearwater plume habitat, but were also associated with riffles and runs in side channel and main
channel habitats (Tables F31 and F32).
• Burbot were observed in in all seasons in a wide variety of macrohabitats and
mesohabitats in tributaries, the main channel Susitna River, and off-channel Susitna River
(Tables F33 and F34). Burbot were widely distributed across habitat types, observations by
mesohabitat were low overall. Counts were similar inside and outside of Focus Areas.
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• Dolly Varden were observed in lower numbers inside of Focus Areas (Table F35) as
compared to outside Focus Areas; however, this pattern was driven by high counts in direct
sample tributaries Fog and Chinook Creeks (Table F36). Dolly Varden were observed in a wide
variety of fast and slow water mesohabitat types and were primarily associated with tributaries
and tributary mouths (Tables F35 and F36).
• Lamprey were observed in all seasons in a variety of fast and slow water mesohabitats in
tributary, side channel, and side slough habitats (Tables F37 and F38). Counts were higher
inside of Focus Areas (70) as compared to outside Focus Areas (5).
• Longnose sucker were found in all seasons in a variety of main channel and off-channel
habitats of the Susitna River and to a lesser extent tributaries (Tables F39 and F40). Highest
counts were associated with slow water mesohabitats, e.g. glides, pools, and backwaters, in side
channels and side sloughs (Tables F39 and F40). Counts were more than twice as high inside of
Focus Areas as compared to outside of Focus Areas.
• Sculpin were found in a wide variety of habitats in the main channel and off-channel
Susitna River as well as tributaries (Tables F41 and F42). High numbers of sculpin were
observed in both fast and slow water mesohabitat types. Counts were similar inside and outside
of Focus Areas.
• Threespine stickleback were observed in all seasons with very high numbers inside and
outside of Focus Areas in MR-7 (Tables F43 and F44). High counts were observed in slow
water habitats, beaver ponds and pools, in upland slough and upland slough beaver complexes.
• Rainbow trout were observed in a wide variety of slow and fast water mesohabitats in the
main channel and off-channel Susitna River with the highest counts made in tributaries (Tables
F45 and F46). Counts were higher inside of Focus Areas as compared to outside Focus Areas.
• Humpback whitefish were observed infrequently inside and outside of Focus Areas in
main channel and off-channel habitats of the Susitna River (Tables F47 and FD48). They were
found predominantly in slow water mesohabitats including backwaters and glides in side
channels and side sloughs.
• Round whitefish were observed in a variety of habitats in the main channel, off-channel,
and, to a lesser extent, tributaries of the Susitna River. They were found predominantly in low to
moderate velocity habitats, e.g. backwaters, glides, and runs within main channel, side channel,
and side slough habitats (Tables F49 and F50). Whitefish that were not differentiated species
were found in similar habitats to round whitefish (Tables F51 and F52).
5.1.3.2. Lower River
Combining counts from available data sources for the Lower River, a total of 11,889 fish
observations were made in Montana Creek (PRM 80.8) and four mainstem Lower Susitna River
geomorphic reaches (Table 5.1-3) during four sampling events. The highest total counts of fish
were obtained in Montana Creek, largely driven by high catches of juvenile salmon in the rotary
screw trap (RST) (Table 5.2.1-1). High fish counts were also obtained in off-channel habitats in
LR-3 and 4 (Table F53); with threespine stickleback in late summer accounting for the majority
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of the observations (Table F75). In general, more fish were observed in off-channel habitats than
in the mainstem reaches (Table F53).
• In the Lower River, adult Chinook salmon were observed on rare occasions in early
summer and late summer and were associated with run and glide habitat associated with
clearwater plumes and tributaries (Table F54).
• Juvenile Chinook salmon were observed in all reaches during every season (Table F55).
Juvenile Chinook were primarily associated with runs and glides in tributary and off-channel
habitats. Among macrohabitat types, juvenile Chinook counts were highest in tributaries, upland
slough beaver complexes, and clearwater plumes (Table F55).
• Adult chum salmon were primarily observed in the fall (Table F56). Highest counts were
observed in pool, run, and clearwater plume habitats associated with tributaries and side sloughs
(Table F56).
• Juvenile chum salmon were observed in highest numbers during the spring Early Life
History sampling (Table F57). Counts were highest in pool, riffle, and run mesohabitats near
spawning areas e.g. tributary, tributary mouths, and side sloughs.
• Adult coho salmon were primarily observed during the late summer in LR-1 (Table F58).
Highest counts were associated with clearwater plumes and tributaries.
• Juvenile coho salmon were observed in all seasons with most observations from tributary
and off-channel habitats in LR-1 and LR-3 (Table F59). Counts were highest in slow to
moderate water velocity mesohabitats (e.g. run, glide, beaver pond, and pool) within tributaries
and upland sloughs with and without beaver complexes (Table F59).
• Adult pink salmon were observed in low numbers with most observations in early
summer within tributary glide habitat in LR-1 (Table F60). No juvenile pink salmon were
observed during systematic sampling.
• Adult sockeye salmon were observed in low numbers in a variety of main-channel, off-
channel and tributary habitats (Table F61).
• High counts of juvenile sockeye salmon were observed in run, glide and pool
mesohabitats within tributary and side slough habitats in LR-1 (Table F62).
• Arctic grayling were observed in early summer through fall in a variety of habitats within
tributaries, the main channel Susitna River, and off-channel Susitna River (Table F64). Counts
were highest in run and glide habitats in tributaries. Juvenile Arctic grayling were observed in a
variety of mesohabitats within side channels, side channel complexes and tributaries (Table F65).
Adult Arctic grayling were observed infrequently with the highest counts in clearwater plumes
(Tables F66 and F67).
• Burbot were observed in early summer through fall in a wide variety of macro and
mesohabitats within tributaries, the main channel Susitna River, and off-channel Susitna River
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(Table F68). Counts by mesohabitat were highest in run and glide habitat within side slough,
side channel complex and main channel macrohabitats.
• Dolly Varden were observed on rare occasions in the Lower River; most observations
were associated with fast water mesohabitat types (riffle, run, and glide) in main and side
channels (Table F69).
• Lamprey were observed in all seasons throughout the Lower River study area. The
highest counts of lamprey were associated with run, clearwater plume, and glide mesohabitats in
both tributary and main channel Susitna River habitats (Table F70).
• Longnose sucker were found in all seasons in a variety of main channel and off-channel
habitats of the Susitna River and, to a lesser extent, tributaries (Table F71). The highest counts
were associated with moderate velocity mesohabitats, e.g. runs and glides, and with upland
slough, side slough, and side slough complex macrohabitats (Table F71).
• Northern pike were found in in a variety of main channel and off-channel habitats of the
Susitna River and to a larger extent, tributaries in LR-4 (Table F72). The highest counts were
associated with pool and glide habitats in a tributary (Fish Creek, PRM 34) and the clearwater
plume at the confluence of Fish Creek with the Susitna River (Table F72).
• Sculpin were found in a wide variety of habitats in the main channel and off-channel
Susitna River as well as in tributaries (Table F73). High numbers of sculpin were observed in
both fast and slow water mesohabitat types.
• Ninespine stickleback were observed in all seasons with highest counts in slow water
pool habitats in tributary, additional open water, and upland slough macrohabitats (Table F74).
• Threespine stickleback were observed in all seasons (Table F75). High counts were
observed in slow water habitats, beaver ponds and pools, in upland sloughs with and without
beaver complexes and tributaries.
• Rainbow trout were observed in a wide variety of slow and fast water mesohabitats in
tributaries, the main channel, and off-channel Susitna River (Table F76). The highest counts
were associated with tributary and upland slough macrohabitats both with and without beaver
complexes.
• Bering cisco were observed on two occasions in the fall in LR-2 and LR-4. Observations
were made in glide and run habitats in side slough and side channel complex macrohabitats
(Table F77).
• Humpback whitefish were observed infrequently in off-channel habitats (side sloughs) of
the Susitna River and on a single occasion in the mainstem and a tributary (Table F78). They
were found predominantly in run and glide mesohabitats.
• Round whitefish were observed in a wide variety of habitats in the main channel, off-
channel, and, to a lesser extent, tributaries of the Susitna River. They were found predominantly
in low to moderate velocity habitats, e.g. glides, runs, and pools (Table F79). Highest counts of
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whitefish that were not differentiated species were found in run habitat within slide slough and
split main channel macrohabitat (Table F80).
Objective 2: Seasonal Movements 5.2.
5.2.1. Task A: Document the timing of downstream movement and catch for all
fish species using out-migrant traps.
Eighteen species and over 11,000 individuals were collected at the four rotary screw traps during
the 2013 sampling period (Table 5.2-1). The trap at Indian River was the most productive of the
four traps, accumulating more than 4,500 individual fish representing 16 species during the 2013
sampling period (Table 5.2-1). This total was 1.6 times greater than the second most productive
trap at Montana Creek, where slightly less than 2,900 fish were collected (Table 5.2-1). The
tributary traps collected more juvenile fishes than the mainstem Susitna River traps. However,
the Susitna River trap at Talkeetna Station (PRM 106.9) was productive collecting nearly 2,700
individuals from all 18 of the species present (Table 5.2-1). In contrast, catch in the Susitna
River at the Curry Station (PRM 124) rotary screw trap was low. Less than 1,500 fish were
caught between June and September at the Curry Station trap (Table 5.2-1). Pacific salmon
species were the most abundant fishes trapped with Chinook, coho, and pink salmon comprising
68 percent of the catch (Table 5.2-1). Most of the salmon caught in traps were juveniles with the
exception of pink salmon. Adults accounted for 77 percent of the pink salmon catch (Table 5.2-
1). The late deployment of the screw traps in June due to late break-up may have limited the
collections of juvenile chum, pink, and sockeye salmon.
The number of juvenile anadromous salmon captured in the four traps by day is shown for each
species in Figures 5.2-1 to 5.2-4. The timing of the 10th and 90th percentile of the cumulative
frequency of catch for the five pacific salmon species is presented in the following sections and
depicted in Figures 5.2-5 to 5.2-8.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations).
5.2.1.1. Chinook Salmon
5.2.1.1.1. Fry
During 2013, there were few Chinook salmon fry collected by rotary screw traps in the mainstem
Susitna River either at Curry Station (Figure 5.2-2, PRM 124) or at Talkeetna Station (Figure
5.2-3, PRM 106). Fry were caught in the mainstem soon after trap deployment in mid-June
through the end of July (Figures 5.2-2 and 5.2-3). Conversely, Chinook salmon fry were
abundant in the tributary catches. The fry size class was observed in the Indian River the day
following trap deployment and their peak abundance occurred during late June to early July
(Figure 5.2-1). Based on the daily frequency distribution, the 90th percentile of the downstream
outmigration had occurred at Indian River by July 21 (Figure 5.2-5). The last fry was observed
in the catch by the end of July (Figure 5.2-1).
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Chinook salmon fry were abundant in the Montana Creek trap catch upon deployment. Peak
observations of fry movement occurred here during the last week of June (Figure 5.2-4). The
90th percentile of the outmigration from Montana Creek had occurred by July 1st (Figure 5.2-8),
after which no fry were observed in the Montana trap counts. Based on the cumulative
frequency distribution, the outmigration timing from Montana Creek was approximately three to
four weeks earlier than from the Indian River site and the outmigration period ended by early-
July (Figures 5.2-5 and 5.2-8).
5.2.1.1.2. Juveniles/Parr
Collections of age-1+ size Chinook salmon that did not show physical signs of smoltification
occurred throughout the open-water season at all sites. The cumulative frequency distributions
and period of these observations extended later in the year than collections of the smolts. This
finding suggests their movements might be more in relation to dispersal than outmigration.
5.2.1.1.3. Smolts
During 2013, Chinook salmon smolts were present in the traps upon deployment in mid- and
late-June. Large numbers of smolts were collected in the tributary locations as well as in the
mainstem Susitna at Talkeetna. Small numbers of Chinook salmon smolts were captured at the
Curry Station trap for a brief period during the third week of June.
A protracted period of downstream movement was observed at the Indian River site with peak
observations of Chinook salmon smolts occurring during the last week of June and early July
(Figure 5.2-1). In contrast to the 1980s data (Roth and Stratton 1985, Roth et al. 1986), more
than 40 percent of the cumulative frequency of the outmigration occurred in the Indian River
after July 1, 2013. The cumulative frequency of age-1+ Chinook salmon captured in 2013 in the
Indian River did not reach 90 percent until September 17th (Figure 5.2-5). Smolt catch continued
until the end of September.
Peak observations of Chinook salmon smolts in the mainstem Susitna River at the Talkeetna trap
also occurred in late June (Figure 5.2-3). Although the 90th percentile of the movement occurred
by July 16, some smolts remained in the Middle River until late September (Figure 5.2-7).
In the Lower River, Chinook salmon smolts in Montana Creek were present upon trap
deployment and their abundance peaked during the month of July (Figure 5.2-4). Ninety percent
of the downstream movement had occurred by August 11 and some smolts were present until the
third week of September (Figure 5.2-8).
5.2.1.2. Chum Salmon
5.2.1.2.1. Fry
Results for chum salmon fry varied during the 2013 outmigration trapping window. Chum
salmon fry were present in the catch at the onset of monitoring in mid- to late-June at all four
traps. However, their peak movements did not occur in the tributary locations until mid-July
(Figures 5.2-1 and 5.2-4). Peak observations in the mainstem Susitna River sites were from late-
July to early-August, a week or two later than the peak movements observed in the tributaries
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(Figures 5.2-2 and 5.2-3). The outmigration from the tributary sites was largely complete by the
end of July or the first week of August and from the mainstem locations by the end of August.
5.2.1.2.2. Juveniles/Parr
Collections of age-0+ chum salmon that did not show physical signs of smoltification were
infrequent. The season average smolt-to-parr ratio of the juvenile chum salmon recorded at the
four sampling locations ranged from 8:1 at Indian River to 22:1 at Montana Creek (Table 5.2-2).
These data show a higher frequency of smolts in trap catch from traps further downstream.
5.2.1.3. Coho Salmon
5.2.1.3.1. Fry
In 2013, coho salmon fry were present in tributary rotary screw traps upon trap deployment, but
were not captured in the mainstem traps until early to mid-July. Peak observations occurred in
the Indian River from mid-June through late July with the 90th percentile of the downstream
movement occurring by August 14 (Figure 5.2-5).
Coho salmon fry movements in the Susitna River at Curry Station peaked between late-July and
late-August reaching the 90th percentile of the frequency distribution on August 30 (Figure 5.2-
6). Coho salmon fry were present at the Curry Station location until early September. These
observations were approximately three weeks earlier than the catch in the Talkeetna Station trap,
approximately 18 river miles further downstream. At Talkeetna Station, the cumulative
frequency of age-0+ coho salmon captured in 2013 did not reach 90 percent until September 20
(Figure 5.2-7). There were insufficient coho salmon fry collections at the Montana Creek trap to
provide a summary of age-0+ movement in tributaries to the Lower River.
5.2.1.3.2. Juveniles/Parr
Large numbers of juvenile coho salmon that did not show physical signs of smoltification were
collected throughout the open-water season at most trapping sites. The cumulative frequency
distributions and period of these observations was similar to smolt collections. The 90th
percentile of the cumulative frequency of recorded juvenile coho salmon and coho salmon parr
occurred on the last day of August at Curry Station and on September 20, at Talkeetna Station
(Figures 5.2-6 and 5.2-7).
The season average smolt-to-parr ratio of the juvenile coho salmon recorded at the four sampling
locations ranged from 0.01:1 at Curry Station to 2:1 at Talkeetna Station and Montana Creek
(Table 5.2-2). These data show a slightly higher frequency of coho salmon smolts in the
Talkeetna Station and Montana Creek traps as compared to the upstream traps at Indian River
and Curry Station.
5.2.1.3.3. Smolts
Coho salmon smolts were collected upon deployment at all four traps. Peak movements were
recorded in the tributary locations between late-July and late-August, while peak coho salmon
smolt movements in the mainstem sites were a week or two later, ranging from late-August to
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early-September. The 90th percentiles of the recorded frequency distributions were during the
last week of August for Indian River and the Susitna River at Talkeetna Station (Figures 5.2-5
and 5.2-7). Ninety percent of the outmigration did not pass the Montana Creek trap until
September 9, 2013 (Figure 5.2-8). Insufficient numbers of coho salmon smolts were captured at
the Curry Station trap to provide information on outmigration.
5.2.1.4. Pink Salmon
5.2.1.4.1. Fry/Smolts
Juvenile age-0+ pink salmon were only captured in large numbers at the Indian River trap during
2013. Few collections were reported at the mainstem Susitna traps and at the Montana Creek
trap. The mainstem collections were consistent with 1980s studies; the last pink salmon fry was
captured at the Talkeetna station on July 26, 2013 (Figure 5.2-3). In 2013, the Indian River trap
collected more than 400 fry during the sampling season providing a sufficient sample size to
assess outmigration timing. Juvenile pink salmon were present at the site when the trap was
deployed on June 17. Peak capture rates were recorded between mid-June through early-July
with 90 percent of the outmigration occurring by July 8 (Figure 5.2-5). However, some young-
of-the-year fr y were captured at the site through the month of July.
5.2.1.5. Sockeye Salmon
5.2.1.5.1. Fry
Few (148) sockeye salmon fry were captured during the 2013 trapping season from the Indian
River or mainstem Susitna River traps and none were observed in Montana Creek in the Lower
River (Table 5.2-1).
5.2.1.5.2. Juveniles/Parr
Collection of age-1+ size sockeye salmon that did not show physical signs of smoltification was
infrequent. The timing of smolts and juvenile catches did not vary markedly among traps during
2013. The season average smolt-to-parr ratio of the juvenile sockeye salmon at Indian River was
7:1; at Talkeetna Station the average ratio was 49:1 (Table 5.2-2). Although the sample size was
small, these data are consistent with the pattern observed for other salmon species in which the
downstream traps captured a higher percentage of smolts.
5.2.1.5.3. Smolts
Age-1+ sockeye salmon smolts were captured mostly at the Indian River and Talkeetna Station
traps during 2013, with a few additional sockeye salmon collected at the Curry Station trap. The
outmigration of smolt-size sockeye salmon at Indian River began in early July and peaked late
July and early August (Figure 5.2-1). The cumulative frequency of the collections reached 90
percent by August 9 (Figure 5.2-5). The outmigration timing in the mainstem Susitna River at
Talkeetna Station was somewhat broader than Indian River during 2013, with smolt-sized catch
starting in mid-June, peaking in mid-July through the end of August, and ending by late
September. The cumulative frequency distribution reached 90 percent by September 14, a month
later than for sockeye salmon smolts that left the Indian River (Figure 5.2-7).
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5.2.2. Task B: Describe seasonal movements using biotelemetry
5.2.2.1. Radio Telemetry
The radio telemetry results below include reporting from fish tagged in July and August and
tracked through the end of August 2013.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_RadioTelemetry).
5.2.2.1.1. Arctic grayling
Movement of radio-tagged fish
Arctic grayling radio-tagged in June primarily moved upstream to tributaries (Table B1). For
example, Fish 9004 (Figure B2) and Fish 9016 (Figure B3) moved 15 to 20 river miles from their
tagging location at Curry to the Indian River and Portage Creek, respectively. Movements were
less pronounced in July and August as fish remained within approximately five river miles of
their tagging location or prior detection.
Identification of foraging and spawning locations
Arctic grayling were observed at a number of potential foraging areas. Radio-tagged fish resided
at the mouths of clear-water streams (Lane, Portage, Fog, and Tsusena creeks and Indian River),
and also moved into some tributaries (Portage Creek and Indian River) for portions of the
summer. Arctic grayling were not spawning during the analysis period of June through August.
Post-Tagging Survival
As of August 31, 20 of the 29 (69 percent) radio-tagged Arctic grayling were alive. Two of the
mortalities occurred within two weeks of the surgery (Table B1).
5.2.2.1.2. Burbot
Movement of radio-tagged fish
Burbot tagged in June moved less than five river miles from their tagging location (Figure B4).
Fish radio-tagged at Talkeetna Station moved downstream to the mouth of the Talkeetna River
(Figure B5), while fish radio-tagged in the Lower River remained near the mouth of the Yentna
River during their short analysis period. The relatively small sample size limits the degree to
which patterns can be inferred.
Identification of foraging and spawning locations
Burbot tended to reside in proximity to the confluence of tributaries during the summer which
may indicate potential foraging locations. Fish were detected near the confluence of the Chulitna
and Susitna rivers, as well as near the confluence of the Yentna and Susitna rivers. Burbot were
not spawning during the analysis period of June through August.
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Post-Tagging Survival
As of August 31, six of the seven (86 percent) of the radio-tagged burbot were alive (Table B2).
The one mortality occurred within two weeks of the fish being radio-tagged.
5.2.2.1.3. Dolly Varden
Movement of radio-tagged fish
A Dolly Varden radio-tagged in June moved 15 river miles upstream in the Susitna and entered
the Indian River in early July (Figure B7). This fish stayed in the Indian River for all of July and
August and ranged over a distance of approximately five river miles. Six Dolly Varden radio-
tagged in early July in the Talkeetna River remained within three river miles of their tag location
(Table B3, Figure B8) for the analysis period. Two fish radio-tagged in August showed
moderate movement with one moving upstream approximately eight river miles and one moving
downstream approximately 20 river miles (Table B3, Figure B6). The relatively small sample
size limits the degree to which patterns can be inferred.
Identification of foraging and spawning locations
Potential foraging areas identified for Dolly Varden were Indian River and Clear/Chunilna Creek
as based on their tendency to reside in these tributary zones during the summer. Dolly Varden
were not spawning during the analysis period of June through August.
Post-Tagging Survival
As of August 31, nine of nine radio-tagged Dolly Varden were alive (Table B3).
5.2.2.1.4. Longnose sucker
Movement of radio-tagged fish
Most longnose sucker remained within two to seven river miles of their tagging location (Table
B4), although some migrated upstream 15 to 20 river miles (Figures B10 and B11). In the first
week of August, at least three fish displayed movements of substantial distance (greater than10
river miles). These movements included an individual that moved upstream from Curry (PRM
124) to the Susitna River in the vicinity of the Indian River confluence (PRM 142) (Figure B11)
and individuals that moved downstream from tagging locations at Indian River and Curry
(Figure B9, Table B4).
Identification of foraging and spawning locations
The mouths of Indian River and Portage Creek were identified as potential foraging areas for
longnose sucker. Additional mainstem locations that may have been foraging locations were
located downstream of Indian River, and both upstream and downstream of the mouth of Lane
Creek. Although the general spawning period is considered May through July, no potential
spawning locations for longnose sucker were identified during the analysis period of June
through August as based on their condition at tagging, and the apparent lack of aggregations.
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Post-Tagging Survival
As of August 31, 14 of the 27 (52 percent) radio-tagged longnose sucker were alive (Table B4).
Seven of the mortalities occurred within two weeks of the fish being radio-tagged.
5.2.2.1.5. Northern pike
Movement of radio-tagged fish
All of the northern pike remained within one river mile their tag site (Table B5). The relatively
small sample size limits the degree to which patterns can be inferred.
Identification of foraging and spawning locations
Northern pike were caught in Fish Creek nears its confluence with Kroto Slough (PRM 34).
This is potentially a foraging area based on habitat characteristics. Northern pike were not
spawning during the analysis period of June through August.
Post-Tagging Survival
Four of the five (80 percent) northern pike radio-tagged in August were alive at the end of
August (Table B5).
5.2.2.1.6. Rainbow trout
Movement of radio-tagged fish
Rainbow trout tagged in the mainstem Susitna during June predominantly migrated upstream 7
to 15 river miles into the lower reaches of tributaries including 4th of July Creek and Indian River
(Table B6, Figures B12 and B13), while fish radio-tagged near tributaries in July predominantly
stayed within two river miles of their tagging location through August (Table B6, Figures B14
and B15). After the initial upstream movement in June, rainbow trout were primarily located in
or near clear-water tributaries (Figure B12).
Identification of foraging and spawning locations
All of the potential foraging locations observed for rainbow trout were in or near clear-water
streams. Tributaries that may have been used for foraging include Indian River and 4th of July,
Clear/Chunilna, and Montana creeks. Rainbow trout had likely finished spawning before the
analysis period as no spawning aggregations were identified. However, with late break-up in
2013, it is possible that upstream movements into tributaries in June could have been related to
spawning.
Post-Tagging Survival
As of August 31, 25 of the 31 (81 percent) radio-tagged rainbow trout were alive (Table B6).
One of the mortalities occurred within two weeks of the fish being radio-tagged.
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5.2.2.1.7. Humpback whitefish
Movement of radio-tagged fish
Most humpback whitefish moved downstream within two weeks after release (Table B7, Figure
B16). It is uncertain if this observation was an indication of a handling or surgery effect, or
documentation of substantial migrations (20 to 30 river miles). The relatively small sample size
from summer tagging limits the degree to which patterns can be inferred. Data from subsequent
tagging events will help to clarify this behavior.
Identification of foraging and spawning locations
There were insufficient detections of humpback whitefish to infer potential foraging locations.
Humpback whitefish were not spawning during the analysis period of June through August.
Post-Tagging Survival
As of August 31, three of the six (50 percent) radio-tagged humpback whitefish were alive
(Table B7). Two of the three mortalities occurred within 2 weeks of the fish being radio-tagged.
5.2.2.1.8. Round whitefish
Movement of radio-tagged fish
Round whitefish radio-tagged in June at Curry displayed a variety of movements. Some fish
moved upstream 35 river miles (Fish 9013, Figure B18), while others moved downstream a
similar distance (Fish 9011, Figure B19). A few remained within five river miles of where they
were radio-tagged (Figure B17). Round whitefish radio-tagged in July remained within five
river miles of where they were radio-tagged (Table B8). Little movement was observed in
August with most fish located in the mainstem Susitna and a few in tributaries (Talkeetna River
and Portage Creek).
Identification of foraging and spawning locations
Round whitefish used two tributaries (Portage and Clear/Chunilna creeks) as potential foraging
locations during the analysis period. In the mainstem of the Susitna River, the mouth of Gold
Creek and Sloughs 11 and 8A were also potential foraging areas. Round whitefish were not
spawning during the analysis period of June through August.
Post-Tagging Survival
As of August 31, 12 of the 14 (86 percent) radio-tagged round whitefish were alive (Table B8).
Both mortalities occurred within two weeks of the fish being radio-tagged.
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5.2.2.2. PIT Tagging
A total of 5,657 2 PIT tags were implanted in 11 different fish species groups in the Middle and
Lower River (Table 5.2-3). Coho salmon were the most frequently tagged species (n=2,092),
followed by Chinook salmon (n=1,696), Arctic grayling (n=378), rainbow trout (n=309), round
whitefish (n=300), and burbot (n=223). Of the fishes implanted with PIT tags and released, 13
percent (n=782) were subsequently resighted in the Middle or Lower River, either via detection
at PIT stream arrays or recaptured during later fish sampling (Table 5.2-3). For the purposes of
the ISR, only recaptures of fish identified to species were used for movement analysis. Thus a
total number of 723 resightings were used to describe movements of the following 9 species.
Coho salmon (n=352) were the species most commonly resighted, followed by Chinook salmon
(n=223), rainbow trout (n=74), Arctic grayling (n=42), burbot (n=32), sockeye salmon (n=8),
Dolly Varden (n=10), round whitefish (23), and humpback whitefish (1). As a percentage of fish
tagged for a given species, rainbow trout (24 percent) and coho salmon (17 percent) were the
most commonly resighted species. Individuals from two species, chum salmon (n =13) and
longnose sucker (n=11) were tagged and released, but never resighted in 2013.
Movements between macrohabitat types were identified by comparing where fish were tagged
and released to where they were subsequently resighted. Detections at fixed arrays (664)
accounted for approximately 85 percent of resightings (Table 5.2-4). The Indian River antenna
was located in a split tributary channel while the Montana Creek antenna was located in a single
tributary channel; these two arrays had moderate numbers of fish detections, 122 and 101 fish
respectively. The other two antenna arrays were located in side slough off-channel macrohabitat,
but the array in Slough 8a detected only 42 fishes while the Whiskers Slough array detected 404
fishes (Table 5.2-4). Rotary screw traps and PIT antennas were situated in fixed locations,
thereby biasing the frequency with which fish were encountered in a given macrohabitat type.
Nonetheless, a comparison of the locations at which fish are tagged and subsequently
encountered offers a means of documenting movement between macrohabitat types.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_PITTagData).
5.2.2.2.1. Chinook Salmon
All Chinook salmon resightings occurred within the same geomorphic reach or downstream of
the reach in which they were tagged. There was only one juvenile Chinook salmon that moved
between stream basins; this 90 mm (3.5 in) fish moved from the Talkeetna Station trap on the
Susitna River to Montana Creek where it was detected by the stream array six days after release.
Eighteen juvenile Chinook salmon exhibited some limited upstream movement (approximately
2 Of these deployed tags, 119 were recorded as duplicate implant codes and 53 had
conflicting species identifications upon recapture. Until information associated with
these tags can be reconciled, they have been excluded from analyses. Thus, the adjusted
dataset consisted of 5,485 PIT-tagged fish.
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100 m [328 ft]) after being tagged at the Indian River rotary screw trap based on their subsequent
detection at the Indian River PIT antenna.
Most of the juvenile Chinook salmon resighted (187) were detected at one of the four PIT
antennas located in the Middle and Lower River (Table 5.2-3). In addition, 44 juveniles were
recaptured at rotary screw traps or during fish sampling in other habitats. Numbers of Chinook
salmon by macrohabitat type in which tagged salmon were released and resighted are displayed
in Table 5.2-5. Of the salmon initially captured and released in main channel habitat, 84 percent
were subsequently encountered in side slough off-channel habitat. Of the salmon initially
captured and released in off-channel habitat, 100 percent of subsequent observations were also in
off-channel habitat, primarily in side sloughs (78 percent). Chinook salmon tagged and released
from tributary habitat were most commonly encountered in the same tributary (65 percent),
although 33 percent were encountered in side slough off-channel habitat in the Susitna River.
5.2.2.2.2. Coho Salmon
All juvenile coho salmon that were resighted were observed within the same geomorphic reach
or downstream of the reach in which they were tagged. Likewise, there was no evidence of any
tagged coho salmon juveniles moving into a tributary from the Susitna River or between
tributaries. Similar to Chinook salmon, 69 tagged juvenile coho salmon exhibited limited
upstream movement (approximately 100 m [328 ft]) from the Indian River rotary screw trap to
the Indian River PIT antenna.
Most PIT -tagged juvenile coho salmon (286) were resighted at one of the four PIT antennas
located in the Middle and Lower River (Table 5.2-3). In addition, 76 juveniles were recaptured
at rotary screw traps or during fish sampling in other macrohabitats. Numbers of coho salmon
released and resighted by macrohabitat type are presented in, Table 5.2-6. The majority of coho
salmon resighted after tagging were found in off-channel habitat (67 percent), primarily side
sloughs (56 percent). Of the juvenile coho salmon tagged in tributary habitat, 37 percent were
later found in off-channel habitat in the Susitna River while 3 percent were encountered in main
channel habitat in the Susitna River. The remaining 60 percent were observed in the same
tributary in which they were tagged.
5.2.2.2.3. Sockeye Salmon
A total of eight juvenile sockeye salmon (60-69 mm [2.4-2.7 in]) were resighted after tagging in
the Middle River. Three were recaptured by fish sampling in the same habitat either later the
same day or the day following tagging in Focus Areas FA-115 (Slough 6A) and FA-128 (Slough
8A). The remaining five salmon were detected by adjacent PIT antennas a few days after
release. One of these five salmon (62mm [2.4 in]) was detected in Indian River. The other four,
were all detected by the Slough 8A PIT array (PRM 129). While these salmon in Slough 8A
were tagged and released on different days (tagging dates September 7, 22, 23), they were all
detected downstream at the Slough 8A PIT antenna three to four days after release (detection
dates September 10, 26, 27).
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5.2.2.2.4. Arctic Grayling
Of the 42 Arctic grayling that were resighted, eight juveniles (mean 94 mm [3.7 in]) were
documented moving between stream basins. Six fish tagged and released at the Talkeetna
Station rotary screw trap (PRM 106.9) and two fish tagged and released at the Indian River
rotary screw trap (PRM 142.1) were detected at the Montana Creek PIT array (PRM 80.9).
These fish were tagged between June 20 and July 16, and detected in Montana Creek between
July 10 and July 31.
Other movements documented included movements within the mainstem Susitna River and
within tributaries. Twenty-two juveniles (mean 82 mm [3.2 in]) tagged in Whiskers Creek on
September 21 were detected at the Whiskers Slough PIT antenna (PRM 105) between September
22 and October 5. Of the 34 tagged Arctic grayling resighted in tributaries, approximately 65
percent were found in side slough off-channel habitat in the Susitna River while 35 percent were
found in tributaries. Only two PIT-tagged, adult Arctic grayling (mean 370 mm [14.6 in]) were
resighted after release. These grayling were released in the Indian River on June 20 and July 16
and detected at the Indian River PIT array between July 17 and August 4.
5.2.2.2.5. Burbot
Thirty one out of the 32 burbot resighted exhibited limited movement and were found in the
same geomorphic reach in which they were tagged and released. Three of these resightings were
of adult burbot (mean TL=530 mm [20.9 in]) and included the one Burbot that moved between
streams. This adult burbot was tagged and released in a Susitna River backwater in MR-7 on
August 2 and was recaptured in the Talkeetna Station rotary screw trap (MR-8; PRM 106.9) on
August 10. The other two adult burbot were tagged in mainstem Susitna River habitats (side
slough and main channel) and were detected post-release at the Whiskers PIT array (PRM 105).
Twenty-two juvenile/adult burbot (mean 409 mm [16.1 in]) were resighted. Of the 10 fish
tagged in main channel habitat, 90 percent were resighted in off-channel habitat. The remaining
12 fish were all tagged, released and resighted in off-channel habitat. Most of the juvenile/adult
burbot resightings occurred at the Whiskers Slough (n=11; PRM 105) and the Slough 8A PIT
(n=9; PRM 129) arrays.
Seven juvenile burbot (mean 177 mm [7 in]) were resighted. Five of these fish were tagged,
released and resighted in off-channel habitat. One burbot tagged in main channel habitat was
recaptured during fish sampling 14 days later, also in main channel habitat. One other juvenile
burbot was tagged in Whiskers Creek and detected the next day at the Whiskers Slough PIT
array (PRM 105).
5.2.2.2.6. Dolly Varden
A total of 10 PIT-tagged Dolly Varden were resighted in the Middle and Lower Susitna River.
Five Dolly Varden were recaptured by the rotary screw trap at the mouth of the Indian River and
then later detected by the Indian River PIT antenna approximately 100m upstream. One adult
Dolly Varden (396 mm [15.6 in]) was released in the Indian River and later was detected
downstream at the Indian River PIT array. Another Dolly Varden was tagged in a beaver
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complex adjacent to the Indian River on July 25 and then approximately one month later was
recaptured downstream in a different pond but within the same beaver complex.
Three Dolly Varden were detected by the PIT antenna located in Whiskers Slough (RM 105).
Two of these fish were tagged upstream in Whiskers Creek while the other fish was originally
tagged in a side channel habitat and detected three days later.
Only one Dolly Varden (213 mm [8.4 in]) was detected at the PIT array in Montana Creek (PRM
80.8) in the Lower River. Originally captured by the Montana Creek rotary screw trap on July
31, this fish was detected upstream (~200 m) on two subsequent occasions, once on August 7
and then again on August 14.
One PIT-tagged Dolly Varden (199 mm [7.8 in]) displayed a more extensive movement pattern
compared to the localized movements of the others. This fish was captured at the Talkeetna
Station rotary screw trap (PRM 106.9) and later detected by the Slough 8A PIT antenna (PRM
129), having traveled 22 miles upstream. It was detected on seven different days between late
June and early July.
5.2.2.2.7. Rainbow Trout
Movements of PIT-tagged rainbow trout were limited. All but one trout were resighted within
the same geomorphic reach in which they were tagged. The one exception, a juvenile trout (76
mm [3 in]) was tagged on August 1 in Unnamed Tributary 113.7 (reach MR-7) and was detected
approximately 9 miles downstream at the Whiskers Slough PIT array (PRM 105 in reach MR-8)
on August 11.
The majority of rainbow trout resightings were in off-channel habitat. Of the fish that were
released in main channel habitat, 90 percent (n=9) of those were resighted in off- channel, side
slough habitat. Likewise, 56 percent (n=30) of tagged trout released in tributary habitat were
resighted in off-channel, side slough habitat.
Five rainbow exhibited movement out of the Susitna River and into tributaries. Two
juvenile/adult rainbow trout tagged and released on June 24 in Susitna River off-channel habitat
(~PRM 141) were detected at the Indian River PIT array (PRM 142.1); one fish (280 mm [11
in]) was detected 2 days later while the other (227 mm [8.9 in]) was detected on several
occasions between June 25 and August 13. An adult trout (370 mm [14.6 in]) was tagged and
released in a side channel of the Susitna River (~PRM 128) on June 14 and detected at the Indian
River PIT array on several occasions between July 12 and July 27. Two juvenile/adult rainbow
trout were tagged and released in a Susitna River side slough near PRM 104 and were resighted
in Whiskers Creek. Both of these juvenile/adult trout were recaptured in Whiskers Creek
(September 21) in between repeated detections in Whiskers Slough.
5.2.2.2.8. Round Whitefish
A total of 23 PIT-tagged round whitefish were resighted in the Middle and Lower Susitna River.
Except for one fish documented in Montana Creek (PRM 80.8) on August 5, all round whitefish
were observed in the Middle River. Within in the Middle River, twelve round whitefish were
detected by PIT antennas nearby original tagging locations. This movement pattern was
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observed at Whiskers Slough (PRM 105; n=4), Slough 8A (PRM 129; n=6), and Indian River
(PRM 142.1; n=2). Although most of these fish were detected on the same day or shortly after
being tagged, one adult round whitefish (335 mm [13.2 in]) was detected at Whiskers Slough
two months after tagging.
Another group of 10 round whitefish displayed more extensive movement patterns. Two fish
tagged in Slough 11 (PRM 138) side slough habitats in June were detected upstream in the
Indian River by the Indian River PIT array, over a month later. Another eight round whitefish
that were tagged and released from a wide range of locations were detected post-release by the
Whiskers Slough PIT array. This included five round whitefish released at Talkeetna Station
(PRM 106.9) who traveled approximately 2 miles downstream, one whitefish released in the
mouth of Slough 6A (PRM 115) who traveled approximately 10 miles downstream, one juvenile
round whitefish released in Slough 8A side channel habitat (PRM 129) who traveled
approximately 24 miles, and juvenile round whitefish who was released from backwater habitat
at the mouth of the Indian River (PRM 142.1) and traveled over 37 miles downstream.
Objective 3: Early Life History 5.3.
A combination of juvenile anadromous and resident fish species were captured during three
Early Life History sampling events between May and June, 2013 (Figure 5.3-1, Table 5.3-1). In
the Middle River, Fog Creek was the only site sampled above Devils Canyon; this stream
supported resident Dolly Varden char and sculpin (Table 5.3-1). Fish found in Middle River
below Devils Canyon included both juvenile salmon and resident fish species. Pacific salmon
juveniles were abundant in these sites, especially newly emerged Chinook, chum, coho and
sockeye salmon fry (Table 5.3-1). Catch of resident fishes primarily consisted of longnose
sucker and sculpin (Table 5.3-1). Other species present in lower numbers included Arctic
grayling, burbot, Dolly Varden, lamprey, rainbow trout, threespine stickleback, and humpback
and round whitefish (Table 5.3-1).
Juvenile anadromous and resident fish species were also present in the Lower Susitna River. The
Lower River fish catch was comprised of juvenile salmon (Chinook, chum, coho, and sockeye),
lamprey, longnose sucker, rainbow trout, sculpin, ninespine stickleback, threespine stickleback,
and round whitefish (Table 5.3-1). Also of note was the presence of northern pike at the
lowermost site (PRM 34) (Table 5.3-1).
Juvenile salmon fry (fork length less than 50 mm [2 in]) were present at the majority of locations
visited during Early Life History sampling (Table 5.3-2). Four species of salmon fry (Chinook,
chum, coho, and sockeye) were documented during the first Early Life History sampling event in
late April to early May. All five species of salmon fry were documented during Events 2 and 3
in June (Table 5.3-2). Chum salmon were the most abundant species of salmon fry documented,
followed by sockeye, Chinook, coho and pink salmon (Table 5.3-2). Although the number of
sites sampled and gear types varied between sampling events, numbers of salmon fry generally
increased between sampling events, with the most fry documented during Event 3 (Table 5.3-2).
Fifty-seven fry were observed during Event 1, 576 fry during Event 2, and 920 during Event 3
(Table 5.3-2). Most of the fish observed in June (Events 2 and 3) were chum salmon fry caught
in a fyke net in FA-138 (Gold Creek) (Table 5.3-2).
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Although AEA was not able to document precise emergence timing, evidence about emergence
timing was collected for all five Pacific salmon species. A few chum, pink and sockeye salmon
alevin and fry were documented in mid-April during the last Winter Study trip (Appendix C) and
Chinook, chum, coho, and sockeye were also collected during the first Early Life History
sampling event from late-April to early-May (Table 5.3-2). Average fork lengths of chum, pink
and sockeye salmon fry during Event 1 in the mid-30’s (mm) indicate that these fish had recently
emerged (Table 5.3-3). In contrast, average fork lengths around 40 mm (1.6 in) for Chinook and
coho salmon observed during Event 1 were longer than in subsequent sampling events,
indicating that some fry emergence for these two species may have occurred later in the open
water period (Table 5.3-3).
A late break-up of ice on the main channel of the Susitna River prevented sampling in May. Not
being able to collect data during this critical time likely limited AEA’s ability to draw
conclusions about spring emergence timing of salmon fry. The fact that only four pink salmon
fry were caught during Early Life History sampling suggests that these fry likely moved
downstream during river break-up (Table 5.3-2).
No clear patterns of movement by salmon fry were observed between spawning and rearing
habitats within sites or between Middle and Lower Susitna River sites during Early Life History
sampling (Table 5.3-2). Although overall numbers of salmon fry increased between sampling
events in the Middle River, many sites in the Lower River were only sampled once, limiting
conclusions regarding fish movement at smaller and larger spatial scales (Table 5.3-2).
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations).
Objective 4: Document winter movements and timing and 5.4.
location of spawning for burbot, humpback whitefish, and
round whitefish.
Documentation of winter movements and spawning locations for burbot, humpback whitefish,
and round whitefish is ongoing. As of January 29, 2014, three burbot, two humpback whitefish,
and ten round whitefish had active tags and were alive in the Middle and Lower River study area
(Table 4.5-3). Additionally, two burbot and nine round whitefish tagged in the Upper River
study area were alive with active tags. Ongoing efforts, including monthly aerial surveys to
relocate tagged individuals and detections at fixed stations, are gathering information that will be
used to address this objective in the Updated Study Report.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_RadioTelemetry).
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Objective 5: Characterize the seasonal size/ life stage structure, 5.5.
growth, and condition of juvenile anadromous and resident fish
by habitat type.
5.5.1. Grow th by Habitat Type
The number of PIT-tagged and recaptured fish used in the growth analysis for the Middle and
Lower Susitna River is presented in Table 5.5-1. Forty-four (44) juvenile Chinook salmon and
two Arctic grayling were recaptured at locations where they could be measured and weighed.
Fish recaptures less than seven days in duration were eliminated from the growth analysis. The
tally of fish with seven days or more in duration between recapture events resulted in a sample
size of 13 Chinook salmon and no Arctic grayling. The site-specific growth rates for juvenile
Chinook salmon are described below:
Of the 13 juvenile Chinook salmon that qualified for the growth assessment, nine were
recaptured in the mainstem Susitna River. One of the mainstem Chinook was collected from the
main channel, while eight were recaptured in off-channel habitat areas including upland sloughs
with beaver complexes and a side slough with a beaver complex (Table 5.5-2).
Although the sample size is small, the data suggest that the month and fish size at tagging had
the largest influence on specific growth rates (Figure 5.5-1). The date of tag implantation
showed a considerable effect on juvenile fish growth. The month of July supported higher
growth than August, while growth during September was minimal. The change in water
temperature and its influence on fish metabolism is likely the underlying reason for this
observation. In addition, small fish grew at a faster rate than large fish (Figure 5.5-1). These
findings are consistent with the scientific literature which suggests that the growth rate of fish is
primarily controlled by the size of the organism and environmental conditions that impact
metabolism.
Juvenile Chinook growth in the Middle and Lower River by habitat types are shown in Figure
5.5-2. Given the small sample size, differential growth rates among habitat types are not
discernable. Tagging month and fish size outweighed any influence of habitat types on specific
growth rates for juvenile Chinook salmon in the Middle and Lower River.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_PITTagData).
5.5.2. Condition Factor by Habitat Type
A summary of the condition factors by habitat type is described for the pilot species below.
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishCondFactors).
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5.5.2.1. Juvenile Chinook Salmon
Juvenile Chinook salmon mean condition factor ranged from 0.88 to 1.59 in the Middle and
Lower River (Table 5.5-3, Figure 5.5-3). This condition factor was relatively consistent across
habitat types with 93 percent of mean values ranging between 0.9 and 1.2. Overall, mean
condition factors were slightly higher in the Lower River compared to those calculated for
Middle River habitat types. The highest mean values were found in Middle River upland slough
and main channel habitat and in Lower River upland slough, tributary, and side channel habitat.
The lowest mean value in the Middle River was in MR-7 side channel habitat. In the Lower
River, the lowest three mean values were very similar and were found in main channel, upland
slough with beaver influence, and side slough habitat. No relationship between mean condition
factor and habitat type was evident for juvenile Chinook salmon in the Middle and Lower River.
5.5.2.2. Arctic Grayling
Arctic grayling mean condition factor was lower and more variable than for juvenile Chinook
salmon. It ranged from 0.73 to 1.17 across all Middle and Lower River habitats and similar to
Chinook salmon, appeared to be slightly greater in the Lower River as compared to Middle River
values (Figure 5.5-4; Table 5.5-4). The highest mean values were found in Middle River main
channel and in Lower River clearwater plume and side channel habitat. In the Middle River, the
lowest three mean values were close and were found in backwater, side slough, and tributary
mouth habitat. The lowest mean value in the Lower River was in tributary habitat. No
relationship between mean condition factor and habitat type was evident for Arctic grayling in
the Middle and Lower River.
Objective 6: Document the seasonal distribution, relative 5.6.
abundance, and habitat associations of invasive species
(northern pike).
Northern pike were the only invasive fish species documented during 2013 field surveys; 62
northern pike were observed during all sampling in the Lower River (Table 5.1-3). As discussed
previously in Section 5.1.1, their documented distribution based on ground surveys was limited
to the lowermost geomorphic reach within the study area (i.e., LR-4; Table 5.1.1-1) and did not
appear to vary on a seasonal basis (Table 5.1.1-12). Furthermore, observations of northern pike
during the early life history and systematic distribution and abundance sampling, which included
42 adults and 15 juveniles, were limited to four sites located in and near Fish Creek (PRM 34.1;
Table 5.6-1). During seasonal distribution and abundance sampling, angling accounted for most
northern pike observations followed by minnow trapping, snorkeling, boat electrofishing,
backpack electrofishing, and seining (Table 5.1-6).
Although five adult northern pike were radio-tagged on August 16, 2013 and subsequently
tracked via aerial surveys, there is currently insufficient information to decipher additional
seasonal distribution patterns for this species. Additionally, the small sample size and a post-
tagging survival rate of 80 percent preclude the interpretation of results (Table 4.5-3). However,
it is worth noting that during the August 16 through 31 tracking period, all tagged fish were
detected within one mile of their tagging location. Radio-tagging and tracking efforts are
ongoing, and additional results will be reported in the Updated Study Report.
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Among gear types, angling accounted for the majority of observations of northern pike (Table
5.1-3). Northern pike angling CPUE during the three angling events conducted in LR-4 ranged
from 0 to 4.7 pike/hour and 0 to 4.4 pike/50 casts (Table 5.6-2). Angling CPUE was highest for
tributary glide habitat. Northern pike CPUE for other gear types presented in the relative
abundance results (minnow trapping, snorkeling, boat electrofishing, backpack electrofishing,
and seining) ranged from 0 at 97 percent of sites to 40 fish per 1,000 m2 in tributary glide habitat
within LR-4 (Table E169).
During the 2013 surveys, northern pike were documented in side slough, clearwater plume, and
tributary habitats (Table 5.6-1; Table D72). Among these 3 habitat types, northern pike were
most abundant within the tributary habitat (i.e., Fish Creek), where 50 of the 57 northern pike
observations occurred. Six fish were found in the clearwater plume at the confluence of Fish
Creek and the Susitna River, and a single juvenile pike was observed in the nearby side slough,
Kroto Slough.
At the mesohabitat scale, northern pike were observed in a variety of mesohabitat types
including glide, pool, clearwater plume, and run (Table 5.6-1; Table D72). The highest counts
for both adults and juveniles were observed in tributary (Fish Creek) glide habitat where 30 and
12 fish were observed, respectively (Table 5.6-1). Eight adults were observed in pool habitat in
Fish Creek, and 4 adults were observed in clearwater plume habitat. In addition to the 12
juveniles documented in Fish Creek glide habitat, 2 juveniles were documented in clearwater
plume habitat, and 1 juvenile was documented in side slough run habitat (Table 5.6-1).
Data developed in support of the ISR is available for download at
http://gis.suhydro.org/reports/isr (ISR_9_6_FDAML_FishObservations, and ISR_9_6_FDA
ML_FishCPUEData).
Objective 7: Collect tissue samples from juvenile salmon and 5.7.
all resident and non-salmon anadromous fish.
Fish tissues were collected opportunistically in conjunction with all fish capture events in
support of the Fish Genetic Baseline Study (Study 9.14). Tissue samples consisted of an axillary
process of the pelvic fin from all adult salmon, caudal fin clips from fish greater than 60 mm (2.4
in), and whole fish less than 60 mm (2.4 in). Tissue collections for anadromous salmonid fishes
are reported in the ISR for the Genetics Baseline Study Plan (ISR Study 9.14, Tables 4-1 through
4-5). The targeted resident and non-salmonid anadromous species and the number of samples are
reported in RSP 9.14 Table 4-6. A summary of fish collected for genetic baseline development
as part of this study is presented in Table 4.10-1.
DISCUSSION 6.
The current status of the Study of Fish Distribution and Abundance in the Middle and Lower
Susitna River is ongoing. As indicated in Section 4, tasks associated with each of the seven
study objectives were initiated in 2013. Additional work for each of the study objectives will
continue in the next year of study.
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Detailed information specific to the status of each of the study objectives is provided in the
sections that follow. The discussions include: an overview of interdependencies with other ISR
studies, the current status of ISR studies that support the specific objectives of the Study of Fish
Distribution and Abundance in the Middle and Lower Susitna River, a summary of key findings
in 2013, and an assessment of the adequacy of the data collected in 2013 to meet the study
objectives. Where applicable, a comparison between 2013 results and previously collected data
in the Middle and Lower River study area is also provided.
Objective 1: Fish Distribution, Relative Abundance, and Habitat 6.1.
Associations
There are three other Susitna-Watana Hydroelectric Project studies that support Objective 1 of
the Study of Fish Distribution and Abundance in the Middle and Lower Susitna River. The
Geomorphology Study (Study 6.5), Characterization and Mapping of Aquatic Habitats Study
(Study 9.9), and the Study of Fish Passage Barriers in the Middle and Upper Susitna River and
Susitna Tributaries (Study 9.12) were initiated in 2012 and have been used to inform the site
selection process for Fish Distribution and Abundance studies in the Middle and Lower Susitna
River study area. These studies also included work conducted in 2013 and will continue through
the next year of study. Study variances in 2013 are not anticipated to affect the successful
completion of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River. The Characterization and Mapping of Aquatic Habitats Study (Study 9.9) will also be
used to describe fish-habitat associations for the Study of Fish Distribution and Abundance in the
Middle and Lower Susitna River.
Work completed under Objective 1 of the Study of Fish Distribution and Abundance in the
Middle and Lower Susitna River supports five other Susitna-Watana Hydroelectric Project
studies. Fish collections in the Middle and Lower River are being used to: 1) help validate fish
periodicity, habitat associations, and selection of target species for reach-specific analyses for the
Fish and Aquatics Instream Flow Study (Study 8.5); 2) provide data on fish use of sloughs and
tributaries with seasonal flow-related or permanent fish barriers for the Study of Fish Passage
Barriers in the Middle and Upper Susitna River and Susitna Tributaries (Study 9.12); 3) and
support the River Productivity Study (Study 9.8) through fish diet sample collections and
information on fish-habitat associations. In addition, patterns of distribution and abundance from
traditional sampling methods will complement information from radio telemetry, fishwheel, and
sonar observations of salmon in the Salmon Escapement Study (Study 9.7). Fish distribution and
abundance is also being used to complement information about harvest rates and effort expended
by commercial, sport, and subsistence fisheries in support of the Fish Harvest Study (Study
9.15).
During the 2013 study year, 18 fish species were documented in the Middle and Lower Susitna
River study area: Chinook salmon, chum salmon, coho salmon, pink salmon, sockeye salmon,
Arctic grayling, burbot, Dolly Varden, lamprey (Arctic), longnose sucker, northern pike, sculpin
(slimy), ninespine stickleback, threespine stickleback, rainbow trout, Bering cisco, humpback
whitefish, and round whitefish. Species diversity was highest in the Lower Susitna River and
declined in an upstream direction. All of the aforementioned species were observed in the Lower
River study area, and with the exception of ninespine stickleback and Bering cisco, all these
fishes were documented in the Middle River study area. Within the Middle River, the fish
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assemblage changed dramatically above Devils Canyon, PRM 153.9-166.1, where a series of
three partial velocity barriers are present that restrict access to upstream habitat. Only Chinook
salmon, Arctic grayling, burbot, Dolly Varden, longnose sucker, sculpin, humpback whitefish
and round whitefish were observed above Devils Canyon.
The species and general distribution documented in 2013 are consistent with historical collection
efforts (AEA 2013c) with two exceptions; ninespine stickleback were documented in the Lower
River and eulachon were missing from 2013 fish distribution surveys. The timing of 2013 fish
distribution surveys was not synched with the eulachon spawning run because there was a
separate study (Study 9.16) focused on eulachon in 2013; documentation of the distribution of
eulachon up to PRM 52.5 is presented in ISR Study 9.16.
With the exception of northern pike, all fish species observed in the Middle and Lower River
study area are considered native to the basin. The distribution of northern pike determined by
2013 surveys was within the distribution described in the 1980s.
Determining the relative abundance of fish species by meso- and macro-habitat was successfully
implemented in 2013. Species- and habitat-specific CPUE was determined for systematic
sampling events at all ELH and fish distribution survey sites. These results showed general
patterns of fish abundance as well as some species-specific patterns.
In general, fish were more abundant in the Middle River than the Lower River and fish in both
these river segments were more abundant than in the Upper River. The highest CPUEs
calculated were in MR-6 and MR-8, primarily associated with tributaries including Indian River,
Whiskers Creek and nearby habitats. In the Lower River the highest CPUEs were in LR-1 and
LR-4. These are similar to general abundance patterns documented in the 1980s. Fish appeared
to be more abundant in habitats inside of Focus Areas than outside.
The most commonly observed species in the Middle River was coho salmon, followed by
threespine stickleback and sculpin. This appears, at first look, to be in contrast with the 1980s
reports of coho salmon being present in low densities. A more detailed comparison of the two
data sets may help to determine if this apparent discrepancy holds true. In the Lower River
threespine stickleback were most common, followed by Chinook salmon juveniles and longnose
sucker. In the 1980s, longnose sucker was considered the most abundant fish in the Lower
River. Abundance patterns for burbot were similar across studies; they were found in low
relative abundance but were widespread across all sampling reaches and habitats. Consistent
with 1980s data, juvenile Chinook and sockeye salmon were most abundant in MR-6 in habitats
in and downstream of Indian River, while coho salmon juveniles were more abundant in MR-8 in
and near to Whiskers Creek and Slough.
Data collected in 2013 allowed AEA to begin to look at species-specific habitat associations.
For the purposes of the ISR, this evaluation was based on total fish observations as a preliminary
approach with provisional data. Once data QA/QC is finalized the CPUE and habitat specific
observational data can be evaluated in concert to develop a species-specific index of habitat use.
This analysis will be completed for the USR. To date, the preliminary analysis is very consistent
with what was determined in the 1980s. In the Middle and Lower River the greatest numbers of
fish observations occurred in off-channel habitats and tributary habitats, predominantly in MR-7
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and MR-6. In addition, the habitats where the greatest number of maximum CPUEs occurred
were consistent between the Middle and Lower River; for macrohabitat types these were
tributaries, upland sloughs and side sloughs and for mesohabitats it was glide/run habitat.
Although sampling with certain gear types resulted in CPUEs equal to zero for many habitat
types and many species, other gear used in the same habitats was successful in catching fish.
This is indicated by relatively low percentages of sites with no fish captured (Tables E1 and
E104). Thus, AEA feels confident that the study design was effective in detecting fish when
present. This is best illustrated by the success of the sampling design in documenting both
widespread and abundant species like Arctic grayling, widespread and less abundant species
such as burbot, and more rare species and life stages including juvenile Chinook salmon in the
Upper River and Arctic lamprey in the Lower River.
Work completed in 2013 is on-track for meeting Objective 1. Work will continue during the
next year of study to obtain additional data to support this task.
Objective 2: Seasonal Movements 6.2.
Objective 2 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is supported by the Salmon Escapement Study (Study 9.7). The Salmon Escapement
Study provides movement data for target species and life stages via fixed receiver and aerial
tracking of radio-tagged fish. The study is ongoing, and variances in 2013 are not anticipated to
affect the successful completion of the Study of Fish Distribution and Abundance in the Middle
and Lower Susitna River.
Work completed under Objective 2 of the Study of Fish Distribution and Abundance in the
Middle and Lower Susitna River supports two other Susitna-Watana Hydroelectric Project
studies. Data collected on movement patterns will be used by the Fish and Aquatics Instream
Flow Study (Study 8.5) to identify seasonal timing and fish distribution patterns among habitat
types in support of the stranding and trapping study component. Fish movement and migratory
timing data will also be utilized by the Study of Fish Passage Barriers in the Middle and Upper
Susitna River and Susitna Tributaries (Study 9.12).
In 2013 AEA was successful in documenting fish movements with three different approaches.
Rotary screw traps were used to document timing of downstream movements in select locations.
Biotelemetry with both radio and PIT tags documented both local and longer distance
movements among habitats for target species. These methods will continue through the winter
of 2013/2014 and into the next study year to further describe fish behavior and habitat use.
Eighteen species and more than 11,000 fish were captured by four Middle and Lower River
rotary screw traps while moving downstream. Traps provided information on Pacific salmon fry
and smolt outmigration timing from Indian River and Montana Creek. In 2013 trap deployment
was delayed as a late break-up coincided with the initiation of glacial melt. Although the
beginning of fry and smolt movements were missed for many species, fry and smolts of all five
anadromous salmon species were caught in some numbers and then the catch diminished
denoting at the end of the outmigration. For some species and life stages, e.g. sockeye salmon in
Indian River, trap catch documented the entire smolt outmigration in 2013. Timing of juvenile
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salmon movement generally was similar to that reported in the 1980s. One exception was the
prolonged outmigration of Chinook salmon smolts. These smolts continued moving downstream
several weeks later than suggested by 1980s data. Changes in smolt-to-parr ratios observed in
trap catch from upstream to downstream traps over time indicates the possibility that some parr
are undergoing physical changes associated with smoltification after leaving the tributaries.
Eight resident fish species were collected from the Middle and Lower River, implanted with
radio tags, and tracked. The data presented for these tagged fishes through August showed
variable degrees of movement. Tagged northern pike were the most sedentary with all tag
detections less than one mile from their release location. Arctic grayling and burbot exhibited
more moderated movements, all less than five miles from their release location. Distances
traveled by Dolly Varden and rainbow trout were more variable among individual fish, with
some fish moving less than 5 miles and others more than 10 miles. Longnose sucker, humpback
and round whitefish exhibited the most extensive movements with some tagged fish moving 15
to 35 miles. Round whitefish moved upstream and downstream of release locations, while all
humpback whitefish moved downstream. Potential foraging locations were determined for all
tagged species, except for humpback whitefish due to a small sample size.
Additional observations of fish movements came from mark and recapture with PIT tags. For
PIT-tagged juvenile Chinook and coho salmon that exhibited movements between different
macrohabitat types, the most frequently observed movement pattern was from main channel or
tributary habitat into off-channel habitat. However, a comparable proportion of resighted
Chinook and coho salmon were found in the same tributary they were tagged in with little to no
movement observed. This is consistent with findings from the 1980s that indicate that a portion
of these juvenile salmon remain in tributaries to rear for a year after emergence.
In contrast to the juvenile salmon, several resident species exhibited movement into tributaries,
either from the main channel of the Susitna River or from other tributaries. This movement
pattern was documented for Arctic grayling, rainbow trout, and round whitefish. However, for
these resident species as well as burbot and Dolly Varden, the most commonly observed
movement pattern was from main channel or tributary habitat into off-channel habitat.
Downstream movement between the Upper and Middle River was documented in 2013. One
humpback whitefish that had been captured while moving downstream in the Oshetna River was
recaptured 16 days later at the Curry Station, having covered a distance of roughly 111 river-
miles. This same fish was then detected 27 days later at the Whiskers Slough PIT array moving
a distance of approximately 131 miles from the original tagging location.
Work completed in 2013 is on-track for meeting Objective 2. However, small sample sizes may
limit the ability to draw conclusions regarding seasonal movement patterns for some species.
Downstream migrant trapping and biotelemetry efforts will continue during the next year of
study to increase sample sizes and obtain additional information on fish movement patterns and
timing.
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Objective 3: Early Life History 6.3.
Objective 3 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is supported by the Fish and Aquatics Instream Flow Study (Study 8.5). The intergravel
temperature component of Study 8.5 was used to estimate fry emergence timing for planning and
implementation of early life history sampling. Conversely, data obtained from Objective 3 will
be used to inform fish periodicity information for analyses conducted as part of the Fish and
Aquatics Instream Flow Study (Study 8.5), and emergence timing and movement data will be
used to support the stranding and trapping component of Study 8.5.
Juvenile salmon fry were present at the majority of Middle and Lower River spring sampling
locations. Both the number of species and counts of fish observed increased from the May to
June sampling events. Chum salmon fry were the most common followed by sockeye, Chinook,
coho and pink salmon. Length data suggested recent emergence for chum, pink and sockeye
salmon in mid-April. In contrast Chinook and coho fry lengths were longer in April than in May
and June indicating that some emergence may be occurring later in the spring for these species.
The very low pink salmon catch compared to other species suggests pink salmon had emerged
and moved past AEA’s sampling locations prior to or coincident with break-up.
These data on emergence compare well with the findings in the 1980s. Pink salmon were
reported to emerge earliest in March and April, followed by chum salmon emergence in April
and sockeye salmon in April and May. In addition, the prolonged emergence for Chinook and
coho salmon fry was inferred at that time, again based on lengths of fish in early summer
samples.
Work completed in 2013 is on-track for meeting Objective 3. Work will continue in the next
year of study in order to collect additional information about juvenile salmonid movement
patterns and timing of movement from spawning to rearing habitats.
Objective 4: Document winter movements and timing and 6.4.
location of spawning for burbot, humpback whitefish, and
round whitefish.
Objective 4 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is not dependent on other ISR studies. However, work completed under Objective 4 will
be used to support the periodicity information needed for Fish and Aquatics Instream Flow Study
(Study 8.5).
Work completed in 2013 is on-track for meeting Objective 4. In conjunction with Objective 2,
seven burbot, seven humpback whitefish, and fourteen round whitefish were surgically
implanted with radio tags and subsequently tracked using radio telemetry in 2013. To meet
Objective 4 (i.e., document winter movement, timing, and spawning locations for burbot and
humpback and round whitefish), these fish will continue to be tracked through the remainder of
2013 and into 2014 and results will be presented in the USR. Furthermore, additional fish may
be radio-tagged as part of the ongoing Fish Distribution and Abundance surveys and will thus
allow for greater sample sizes when tracking fish in the next year of study.
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Objective 5: Characterize the seasonal size/ life stage structure, 6.5.
growth, and condition of juvenile anadromous and resident fish
by habitat type.
Objective 5 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is not dependent on other Project studies. However, work completed under this objective
supports four other ISR studies. Growth data, along with information on fish movement and
habitat associations, will be used as inputs for bioenergetics and trophic analysis modeling for
the River Productivity Study (Study 9.8). Additionally, growth and movement data will be used
to support the stranding and trapping study component of the Fish and Aquatics Instream Flow
Study (Study 8.5).
To meet Objective 5, nearly 15,000 paired length-weight measurements representing 18 species
(Chinook salmon, chum salmon, coho salmon, pink salmon, sockeye salmon, Arctic grayling,
burbot, Dolly Varden, lamprey, longnose sucker, northern pike, rainbow trout, sculpin, ninespine
stickleback, threespine stickleback, Bering cisco, humpback whitefish, and round whitefish)
were collected in 2013. Because data QA/QC is ongoing, growth analysis for the ISR was
limited to two example species: Chinook salmon and Arctic grayling.
The fish growth analysis was limited to data available for 13 juvenile Chinook that were PIT-
tagged and recaptured more than 7 days post-release. The analysis suggests that growth rates are
influenced by both month and the size of fish at tagging. Such seasonal variation is likely related
to water temperature and its effect on fish metabolism. It was also noted that smaller fish had
greater growth rates. There was insufficient recapture data to compare growth rates among
habitat types.
Condition factor analysis was conducted for 919 juvenile Chinook salmon and 600 Arctic
grayling. Condition factors for juvenile Chinook salmon were greater than 1.0 in all Middle
River habitat types and most Lower River habitat types. Chinook salmon condition factors were
highest in Middle River main channel and Middle and Lower River upland slough habitat.
Arctic grayling condition factors were less than 1.0 in all but one habitat type. On average
Arctic grayling condition factors were higher in the Lower River than the Middle River. The
highest Arctic grayling condition factors (approximately 0.9) were found primarily in fast water
habitats.
Work completed in 2013 is on-track for meeting Objective 5. However, sample sizes for growth
analyses are currently limited. Work will continue during the next year of study to increase
sample sizes for the size-class, growth, and condition factor analyses.
Objective 6: Document the seasonal distribution, relative 6.6.
abundance, and habitat associations of invasive species
(northern pike).
Objective 6 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is not dependent on other Project studies. However, results of this study objective will be
used to: 1) complement information about harvest rates and effort expended by commercial,
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sport, and subsistence fisheries in support of the Fish Harvest Study (Study 9.15), and 2) inform
the Future Watana Reservoir Fish Community and Risk of Entrainment Study (Study 9.10) on
the presence/absence of northern pike and lake trout in the Watana Reservoir inundation zone.
Northern pike were the only non-native or invasive fish species documented in the Middle and
Lower Susitna River study area during field surveys conducted in 2013. Pike were illegally
transplanted into several lakes of the Yentna River in the 1950s (Delaney et al. 1981). During the
1980s Aquatic Studies Program, five northern pike were captured in the Lower River: one in
Kroto Slough (PRM 34.1), 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 in more than 100 lakes and more than a dozen
tributaries of the Lower Susitna River (Oslund and Ivey 2010; Sepulveda et al. 2013). The
expansion of pike and predation on salmonids is hypothesized to be a leading cause for the
decline of multiple salmonid species in lower Susitna streams that once supported popular sport
fisheries (Rutz 1999; Sepulveda et al. 2013). In the present study, northern pike distribution was
limited to the Fish Creek/Kroto Slough area (PRM 34.1) near the Yentna River confluence and
the downstream boundary of the study area. However, the known range of northern pike
includes tributaries of the Susitna upstream of Fish Creek including: Deshka River (PRM 45),
Caswell Creek (PRM 67), Montana Creek (PRM 80.8), Rabideux Creek (PRM 87.8), Birch
Creek (PRM 92.5), and Trappers Creek (PRM 94.5) (Oslund and Ivey 2010). Preliminary radio
telemetry results found that all surviving tagged fish (N = 4) remained within one mile of their
tagging location at Fish Creek.
Northern pike have broad physio-chemical tolerances allowing them to inhabit a wide range of
habitats from lakes to sloughs to streams; distribution and abundance is primarily a function of
prey resource availability (SANPCC 2007). Most northern pike observations in 2013 occurred in
tributary habitats, although some fish were also observed in the clearwater plume of Fish Creek,
and a single fish was observed in a nearby side slough (Kroto Slough). At the mesohabitat scale,
use of clearwater plumes, runs, glides, and pools was observed. Adults and juveniles were most
commonly found in tributary glide habitat. Catch-per-unit-effort was also highest in tributary
glide habitat within LR-4 (4.7 pike/angling hour; 40 pike/1,000 m2 snorkeled).
Work completed in 2013 is on-track for meeting Objective 6. Although the radio telemetry
sample size is currently limited, the presence of non-native species will continue to be
documented during surveys conducted in the next year of study, and additional fish will be radio-
tagged, when feasible. Furthermore, additional radio telemetry tracking data is expected to be
available for describing seasonal distribution patterns.
Objective 7: Collect tissue samples from juvenile salmon and 6.7.
all resident and non-salmon anadromous fish.
Objective 7 of the Study of Fish Distribution and Abundance in the Middle and Lower Susitna
River is not dependent on other Project studies. However, fish tissue sample collections are
being used to support the Genetics Baseline Study for Selected Fish Species (Study 9.14).
During fish distribution and abundance sampling in the Middle and Lower River in 2013, 799
tissue samples representing 15 species were collected for genetics analysis. Samples were
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collected from Chinook, coho and sockeye salmon, Arctic grayling, burbot, Dolly Varden,
lamprey, longnose sucker, northern pike, rainbow trout, sculpin, ninespine stickleback, Bering
cisco, humpback whitefish, and round whitefish. Results are presented and discussed in ISR
Study 9.14.
Work completed in 2013 is on-track for meeting Objective 7. Work will continue during the
next year of study to meet the established target sample sizes.
COMPLETING THE STUDY 7.
[As explained in the cover letter to this draft ISR, AEA’s plan for completing this study will be
included in the final ISR filed with FERC on June 3, 2014.]
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LITERATURE CITED 8.
Adams, F.J. 1999. Status of rainbow trout in tributaries of the upper King Salmon River, Becharof
National Wildlife Refuge, Alaska, 1990-92. U.S. Fish and Wildlife Service, Alaska Fisheries
Technical Report Number 53, King Salmon, Alaska.
Alaska Department of Fish and Game (ADF&G). 1981. APA Report 318, Subtask 7.10. Phase 1,
Final draft report. Resident fish investigation on the lower Susitna River. Anchorage, AK.
99503.
ADF&G. 1982. Aquatic Studies Procedures Manual: Phase I. Prepared by Alaska Department of Fish
and Game, Su-Hydro Aquatic Studies Program. Prepared for Alaska Power Authority,
Anchorage, Alaska. pp 111.
ADF&G. 2012. Anadromous Waters Catalog. http://www.sf.adfg.state.ak.us/SARR/AWC/index.cfm.
Accessed December 2012.
ADF&G. 1984. Susitna Hydro aquatic studies report no. 1. ADF&G, Susitna Hydro Aquatic Studies
Report Series, Susitna Hydro Document No. 1450, Anchorage, Alaska.
Alaska Energy Authority (AEA). 2012. Revised Study Plan: Susitna-Watana Hydroelectric
Project FERC Project No. 14241. December 2012. Prepared for the Federal Energy
Regulatory Commission by the Alaska Energy Authority, Anchorage, Alaska.
http://www.susitna-watanahydro.org/study-plan.
Buckwalter, J.D. 2011. Synopsis of ADF&G's Upper Susitna Drainage Fish Inventory, August
2011. Alaska Department of Fish and Game, Division of Sport Fish, Anchorage, Alaska.
27 pp.
Buckwalter, J. D., J. M. Kirsch, and D. J. Reed. 2012. Fish inventory and anadromous cataloging in
the upper Koyukuk River and Chandalar River basins, 2010. Alaska Department of Fish and
Game, Fishery Data Series No. 12-22, Anchorage.
Burr, 1993. Maturity of lake trout from eleven lakes in Alaska. Northwest Science, Vol 67, No. 2,
1993. Connolly, P.J., I.G. Jezorek, K.D. Martens, and E.F. Prentice. 2008. Measuring the
Performance of Two Stationary Interrogation Systems for Detecting Downstream and
Upstream Movement of PIT-Tagged Salmonids. North American Journal of Fisheries
Management 28:402-417.
Delaney, K., D. Crawford, L. Dugan, S. Hale, K Kuntz, B. Marshall, J. Mauney, J. Quinn, K.
Roth, P Suchanek, R. Sundet, and M. Stratton. 1981. Resident Fish Investigation on the
Lower Susitna River. Prepared by Alaska Department of Fish and Game, Susitna Hydro
Aquatic Studies. Prepared for Alaska Power Authority, Anchorage, AK. 311 pp.
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MIDDLE AND LOWER SUSITNA RIVER STUDY (9.6)
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Docker, M. F. 2009. A review of the evolution of nonparasitism in lampreys and an update of the
paired species concept. Pages 71-114 in L. R. Brown, S. D. Chase, M. G. Mesa, R. J.
Beamish, and P. B. Moyle, editors. Biology, management, and conservation of lampreys in
North America, American Fisheries Society Symposium 72. American Fisheries Society,
Bethesda, MD.Dolloff, C.A., D.G. Hankin, and G.H Reeves. 1993. Basinwide Estimation of
Habitat and Fish Populations in Streams. USDA Forest Service General Technical Report
SE-GTR-83. pp 25.
HDR Alaska, Inc. 2013. 2012 Upper Susitna River Fish Distribution and Habitat Study: Fish
Distribution Report. Susitna-Watana Hydroelectric Project. April 2013.
Heard, W. R. 1966. Observations on lampreys in the Naknek River System of Southwest
Alaska.Copeia 1966(2):332-339.
Hillman, T.W., J.W. Mullan, J.S. Griffith. 1992. Accuracy of Underwater Counts of Juvenile
Chinook Salmon, Coho Salmon, and Steelhead. North American Journal of Fisheries
Management 12:598-603.
Fulton, T. W. 1902. The rate of growth of fishes. 20th Annual Report of the Fishery Board of
Scotland 1902 (3):326-446.
Fulton, T. W. 1904. The rate of growth of fishes. 22nd Annual Report of the Fishery Board of
Scotland 1904 (3):141-241.
Grubbs, F.E. 1950. Sample criteria for testing outlying observations. Ann. Math. Stat. 21, 1, 27-
58.
Lukasz K. 2011. Outliers: Tests for outliers. R package version 0.14. http://CRAN.R-
project.org/package=outliers.
Murphy, B.R., and D.W. Willis, editors. 1996. Fisheries Techniques, 2nd edition. American Fisheries
Society, Bethesda, Maryland.
National Marine Fisheries Service (NMFS). 2000. Guidelines for Electrofishing Waters Containing
Salmonids Listed Under the Endangered Species Act.
Oslund, S. and S. Ivey. 2010. Area management report for the recreational fisheries of Northern
Cook Inlet, 2009 and 2010. Alaska Department of Fish and Game Fishery Management
Report No 10-50. 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.
R2 Resource Consultants, Inc. (R2), 2013a. Adjustments to Middle River Focus Areas Technical
Memorandum. Susitna-Watana Hydroelectric Project. May 2013.
R2. 2013b. Synthesis of Existing Fish Population Data. Susitna-Watana Hydroelectric
Project. February 2013.
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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. pp 130.
Russell, R. 1977. Rainbow trout life history studies, in the lower Talarik Creek-Kvichak Drainage.
Alaska Department of Fish and Game, Completion Report, D-J Study G-II-E, Juneau, AK.
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.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. pp 185.
Sepulveda, A.J., D.S. Rutz, S.S. Ivey, K.J. Dunker, and J.A. Gross. 2013. Introduced northern
pike predation on salmonids in southcentral Alaska. Ecology of Freshwater Fish. 12 pp.
Southcentral Alaska Northern Pike Control Committee (SANPCC). 2007. Management plan for
invasive northern pike in Alaska. Alaska Department of Fish and Game, Sport Fish Divi
sion, Anchorage, AK. 58pp.
Temple, G.M., and T.N. Pearsons. 2007. Electrofishing: Backpack and Drift Boat. In Salmonid Field
Protocols Handbook: Techniques for Assessing Status and Trends in Salmon and Trout
Populations. State of the Salmon. Portland, Oregon. pp 95-132.
Thurow, R.F. 1994. Underwater Methods for Study of Salmonids in the Intermountain West. U.S.
Dept. of Agriculture, Forest Service, Intermountain Research Station. General Technical
Report INT-GTR-307. Odgen, Utah. pp 28.
Vladykov, V. D., and E. Kott. 1978. A new nonparasitic species of the holarctic lamprey genus
Lethenteron Creaser and Hubbs, 1922 (Petromyzontidae) from northwestern North America
with notes on other species of the same genus. University of Alaska, Fairbanks, AK.
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TABLES 9.
Table 2-1. Proposed methods by objective, task, species, and life stage.
Obj Task
Species/
Life Stage Study Sites Proposed Methods by Season
1A Distribution Juvenile salmon,
non-salmon
anadromous,
resident
Focus Areas +
representative
habitat types
Select Focus
Areas
(accessible)
Ice Free Season:
• Single pass sampling
• Selection of methods will be site-specific, species-specific, and life-stage-specific.
• For juvenile and small fish sampling, electrofishing, snorkeling, seining, fyke nets,
angling, DIDSON and video camera where feasible and appropriate.
• For adults, directed efforts with seines, gillnets, trot lines, and angling.
• To the extent possible, the selected transects will be standardized and the methods
will be repeated during each sampling period at a specific site to evaluate temporal
changes in fish distribution.
• Additional info from radio telemetry studies (Objective #2).
Winter:
• Based on winter 2012-2013 pilot studies
• Potentially DIDSON, video camera, minnow traps, e-fishing, seines, and trot lines.
1B Relative abundance Juvenile salmon,
non-salmon
anadromous,
resident
Focus Area
study sites +
representative
habitat types
• Multi-pass sampling
• To the extent possible, the selected transects will be standardized and the methods
will be repeated during each sampling period at a specific site to evaluate temporal
changes in fish distribution.
• Snorkeling, beach seine, electrofishing, fyke nets, gillnet, minnow traps, fish
wheels, out-migrant traps, etc.
1C Fish habitat associations Juvenile salmon,
non-salmon
anadromous,
resident
Focus Area
study sites+
representative
habitat types
• Analysis of data collected under Objective 1: Distribution. Combination of fish
presence, distribution, and density by meso-habitat type by season.
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Obj Task
Species/
Life Stage Study Sites Proposed Methods by Season
2A Timing of downstream
movement and catch using
out-migrant traps
All species;
juveniles
At selected out-
migrant trap &
PIT tag array
sites
• Out-migrant Traps: Maximum of 6. 2-3 Main channel to indicate broad timing of
out-migrants from all upstream sources. 3-4 in tributary mouths and sloughs, such
as Fog Creek, Kosina Creek, Portage Creek, Indian Creek and possibly Gold
Creek and Whiskers Slough. Combine with fyke net sampling to identify key site-
specific differences.
• Sampling in mainstem lateral habitats downstream of tributaries with fyke nets,
seines, and out-migrant traps
• Fishwheels (adults only) opportunistically in conjunction with the Salmon
Escapement Study
2B Describe seasonal
movements using
biotelemetry (PIT and radio
tags)
All species Ice-Free Season:
• PIT tags: tags opportunistically implanted in target species from a variety of capture
methods in Focus Areas. Antenna arrays in up to 10 sites at selected side
channel, side slough, tributary mouth, and upland sloughs in the Middle River and
Lower River.
• Radio tags surgically implanted in up to 30 individuals of sufficient body size of
each target species distributed temporally and longitudinally. .
Winter:
• Based on winter 2012-2013 pilot studies.
• Potentially DIDSON, video camera, minnow traps, electrofishing, seines and trot
lines.
• Aerial tracking of radio tags (adults).
3A Describe emergence timing
of salmonids;
Juvenile salmonids Select Focus
Areas • Bi-weekly sampling using fyke nets, seines, electrofishing and minnow traps in
salmon spawning areas within Focus Areas.
3B Determine movement
patterns and timing of
juvenile salmonids from
spawning to rearing
habitats;
Juvenile salmonids Focus Areas • Focus on timing of emergence and movement of newly emergent fish from
spawning to rearing areas or movement of juvenile fish <50 mm in winter (i.e., the
post-emergent life stages most vulnerable to load-following operations)
• DIDSON or underwater video to monitor movement into or out of specific habitats
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Obj Task
Species/
Life Stage Study Sites Proposed Methods by Season
3C Determine juvenile
salmonid diurnal behavior
by season
Juvenile salmonids Focus Areas • Stratified time of day sampling to determine whether fish are more active day/night
• DIDSON and/or video camera methods to observe fish activity
• Potentially electrofishing and seining
3D Collect baseline data to
support the Stranding and
Trapping Study
Focus Areas +
supplement with
additional
representative
habitat types as
necessary.
• Opportunistic support to ID seasonal timing, size and distribution among habitat
types for fish <50 mm in length.
• Estimate presence/absence, relative abundance, and density using similar
methods as Objectives 1A, 1B, 1C, and 2 for fish <50 mm
• Focus on slough and other mainstem lateral habitats
• DIDSON, video camera, electrofishing, seines, out-migrant traps and fyke nets.
• Monthly measurements of fish size/ growth
4 Winter movements, timing,
and location of spawning
burbot, humpback
whitefish, and
round whitefish
Mainstem
habitats • Radio tags surgically implanted in up to 30 fish of sufficient body size of each
species distributed temporally & longitudinally.
• To capture burbot for radio-tagging, use hoop traps late Aug-early Oct following
methods by Evenson (1993).
• To capture whitefish for radio-tagging, use fish wheels opportunistically and
directed efforts including angling, seines & gillnets.
• Use aerial & snow machine tracking of radio tags to pinpoint winter aggregations of
fish; sample these areas with trot lines (similar to 1980s). Trot lines are lethal
sampling.
• Collect, examine, and preserve gonads to determine spawning status.
5 Document age structure,
growth, and condition by
season
juvenile
anadromous and
resident fish
All study sites for
Obj 1B and
Focus Areas
• Stock biology measurements- length from captured fish up to 100 individuals per
season per species per life stage and up to 30 fish per month per species per
habitat type in Focus Areas.
• Emphasis placed on juvenile salmonids <50mm.
• Opportunistically support Stranding and Trapping Study
6 Seasonal
presence/absence and
habitat associations of
invasive species
northern pike All study sites • Same methods as #1 and #2 above.
• The presence/absence of northern pike and other invasive fish species will be
documented in all samples
• Additional direct efforts with angling as necessary
7 Collect tissue samples to
support the Genetic
Baseline Study
All All study sites in
which fish are
handled
• Opportunistic collections in conjunction with all capture methods listed above.
• Tissue samples include axillary process from all adult salmon, caudal fin clips from
fish >60 mm, and whole fish <60 mm.
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Table 4.1-1 Salmon early life history sampling effort, 2013.
Location
ELH Event 1 (pre-break-up) ELH Event 2 ELH Event 3
Start date End date Start date End date Start date End date
4/28/13 5/3/13 6/1/13 6/15/13 6/20/13 6/29/13
Number of sites Number of sites Number of sites
Middle River
Fog Creek PRM 179.3 3a 3a
Fog Creek Lake 1a 1a
Devils Canyon (PRM 153.9-166.1)
FA-144 (Slough 21) 6 6
FA-141 (Indian River) 6 6
FA-138 (Gold Creek) 2 6 6
FA-128 (Slough 8A) 5 6 6
FA-113 (Oxbow I) 6 6
FA-104 (Whiskers Slough) 3 6 6
Lower River
Trapper Creek PRM 100.3 3b 3b
Unnamed Tributary PRM 100.3 3b
Sunshine Creek PRM 88.2 3b
Rabideaux Creek PRM 87.8 3b
Montana Creek PRM 80.8 3b
Goose Creek PRM 76.2 3b
Tributary Mouth PRM 63.5 3b
Upland Slough PRM 63.5 3b 3b
Little Willow Creek PRM 54.3 3b 3b
Side Slough PRM 52.0 3b
Fish Creek PRM 34.1 3b 3b
Fish Creek Mouth PRM 34.1 3b 3b
Grand Total 10 58 73
asampling consisted of 100 m (328 ft) unit
bsampling consisted of 3, 40-meter reaches within a 200 m (656 ft) unit
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Table 4.1-2. Tributaries sampling effort for fish distribution in the Middle River above Devils Canyon by geomorphic reach, 2013.
Target Tributary Geomorphic Reach PRM Listed in AWC
Average
Wetted Width1 (m)
Drainage
Basin Area (km2)
Average
Channel Width2 (m) Accessibility Sample Type Number of Sites
Tsusena Creek 2 184.5 No 10 374.3 NA Unknown Direct 2
Unnamed Tributary 184 2 184.0 No NA NA NA None Direct -
Fog Creek 2 179.3 Yes 9 381.2 20 Unknown Direct 5
Fog Trib 2 N/A Yes NA NA NA Unknown Direct 6
Upstream extent Devils Canyon (PRM 166.1)
Devil Creek 3 164.8 No 22 190.6 11 None Direct -
Impediment 3 in Devils Canyon
Chinook Creek 3 160.4 Yes 9 58.3 8 Unknown Direct 2
Cheechako Creek 4 155.9 Yes 12 94.3 8 None Direct -
Downstream extent Devils Canyon (PRM 153.9)
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Table 4.1-3. Habitat types and number of sites sampled for distribution and relative abundance sampling in the Middle River, 2013.
Focus
Strata Habitat Strata
Geomorphic Reach Total MR-1 MR-2 MR-5 MR-6 MR-7d MR-8
Targeted Sampled Targeted Sampled Targeted Sampled Targeted Sampled Targeted Sampled Targeted Sampled Targeted Sampled
Focus
Areas
Main Channel 3 2 3 3 2e 2 3 1 3 1 3 3 17 12
Split Main Channelf 1 1 3 1 3 6 3f
Multi-Split Main
Channelf 3 1 1 3 2f
Side Channel 2e 2 3 3 3 3 3 3 3 3 14 14
Side Slough 3 3 3b 1b 3 3 9 7
Side Slough Beaver
Complex 3 5c 3 5
Upland Slough 3 0a 3 3 3b 1b 3b 12 4
Upland Slough
Beaver Complex 3 3 3d 5c 3c 6 11
Backwater 1 1 1 2 2 3 4
Tributary 1 0a 1 0a 2 2 3d 3 1 1 8 6
Tributary Mouth 1 1 1 0a 2 2 1d 1 5 4
Clear Water Plume 1 1 1 1 1 1 2 4
Subtotal Focus
Areas Abundance 5 5 14 12 5 3 27 24 21 19 16 13 88 76
Non
Focus
Areas
Main Channel 3 3 3 1 3 2 3 3 3 1 3 2 18 12
Split Main Channelf 3 1 3 1 3 3 2 3 1 15 5f
Multi-Split Main
Channelf 3 3 6 0f
Side Channel 1e 1 3 3 3 3 3 3 3 3 13 13
Side Slough 3 3 3 3 3 3 3 3 3 3 15 15
Side Slough Beaver
Complex 3 3 3 3
Upland Slough 3 0a 3 2a 3 1b 3 3 12 6
Upland Slough
Beaver Complex 3 3 3 5c 6 8
Backwater 1 1 3 3 1 1 1 1 6 6
Tributary 3 0a 3 2a 3 3 9 5
Tributary Mouth 3 2 1 0a 3 3 2d 2 9 7
Clear Water Plume 3 3 3 2 1 1 7 6
Subtotal Non-Focus Areas Distribution1 2 2 16 7 6 3 22 15 17 14 12 7 75 48
Subtotal Non-Focus Abundance 2 2 9 7 4 3 11 9 11 11 7 6 44 38
Subtotal Non-Focus 4 4 25 14 10 6 33 24 28 25 19 13 119 86
Subtotal Samples For
Distribution 2 2 16 7 6 3 22 15 17 14 12 7 75 48
Subtotal Samples For
Abundance 7 7 23 19 9 6 38 33 32 30 23 19 132 114
Total number of sampling sites 9 9 39 26 15 9 60 48 49 44 35 26 207 162
Notes:
a:Site not accessible to sample CIRI Lands or Alaksa Railroad Corporation
b: Sloughs w/o Beaver Complexes were found upon visitation to support beaver activity and were reclassified.
c: Sloughs with Beaver Complexes were added due to observed beaver activity in classified Upland Sloughs or Side Sloughs w/o Beaver Complexes.
d: Number of target sites per strata modfied from IP table 5.3-1 with inclusion of FA-113 (Oxbow I) in MR-7, May 2013
e: Number of target sites modified from IP Table 5.3-1 due to sample unit length increases
f: This strata combined into Main Channel for site selection purposes
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Table 4.1-4. Habitat types sampled for fish distribution in the Lower River by transect and reach in 2013.
Geomorphic
Reach
Transect
PRM
Sample
Type
Habitat Type
Main Channel
Side Channel Complex
Bar Island Complex
Side Channel Upland Slough Side Slough Slough Mouth Tributary Tributary Mouth
Additional
Open
Water
Total
LR1 100.3 Abundance 1 1 1 1 1 1 6
LR1 92.9 Distribution 1 1 1 1 1 5
LR2 85.6 Distribution 1 1 2
LR2 78.2 Distribution 1 1 2
LR2 70.8 Abundance 1 1 1 1 4
LR3 63.5 Abundance 1 1 1 1 1 1 6
LR3 56.1 Distribution 1 1 1 1 1 5
LR3 48.8 Distribution 1 1 2
LR4 41.4 Distribution 1 1 1 1 1 1 6
LR4 34.0 Abundance 1 1 1 1 1 1 6
Total Abundance 3 3 1 1 1 2 2 4 4 1 22
Total Distribution 4 4 2 3 1 1 1 2 2 2 22
Total Sites Lower River 7 7 3 4 2 3 3 6 6 3 44
Estimated in Implementation Plan 10 10 10 6 4 0 2 2 44
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Table 4.1-5. Antenna orientation for fixed-station receiver locations in the Middle and Lower Susitna River, 2013.
Station PRM Install
Date Status
Antenna Orientation
Rationale Antenna 1 Antenna 2 Antenna 3
Montana
Creek 81 4-Jun Installed
Down
Montana
Cr.
Up Montana
Cr. - Salmon spawning stream
Middle River 102.4
Whiskers
Creek 105 5-Jun Installed Down
Susitna Up Susitna
Up
Whiskers
Cr.
Salmon spawning stream;
Possible burbot holding area
Lane Creek 117 3-Jun Installed Down
Susitna Up Susitna Across
Susitna
Monitor for Curry tagged fish
moving downstream; Monitor
for Lower River tagged fish
moving into Middle River
Gateway 130 7-Jun Installed Down
Susitna Up Susitna - Monitor for Curry tagged fish
moving upstream
4th of July
Creek 134 8-Jun Installed Down
Susitna Up Susitna Up 4th of
July Cr.
Between Gateway and
Indian. Rainbow trout
stream.
Indian River 142 8-Jun Installed Down
Susitna Up Susitna Up
Indian Salmon spawning stream
Upper
Indian River N/A 30-Jun Installed Down
Indian Up Indian -
Salmon spawning stream;
Accurate records of fish
moving into tributary
Powerline 146 11-Jun Replaced
Portage Creek
Down
Susitna Up Susitna -
Monitor fish moving
upstream towards Portage
Creek
Portage
Creek 152 N/A Not installed due
to land access
Down
Susitna Up Susitna - Salmon spawning stream
Upper
Portage
Creek
N/A N/A Not installed due
to land access
Down
Portage Cr.
Up Portage
Cr. -
Salmon spawning stream;
Accurate records of fish
moving into tributary
Downstream extent Devils Canyon PRM 153.9
Cheechako
Creek 156 N/A Not installed due
to land access
Down
Susitna Up Susitna - Monitor site for fish passing
above Impediment 1
Chinook
Creek 160 N/A Not installed due
to land access
Down
Susitna Up Susitna - Monitor site for fish passing
above Impediment 2
Upper Extent Devils Canyon PRM166.1
Devils
Island 167 27-Jun Installed Down
Susitna Up Susitna - Monitor site for fish passing
above Impediment 3
Fog Creek 179 N/A Not installed due
to land access
Down
Susitna Up Susitna Up Fog
Cr.
Large accessible salmon
spawning tributary with lake
access
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Table 4.1-6. Habitat types sampled during 2012/13 winter pilot study.
February 1-7 Habitat Type
Gear Type Tributary Tributary
Mouth
Upland
Slough
Side
Slough
Slough
Mouth
Side
Channel
Main
Channel
Other off-
channel
Minnow Trap WS WS WS WS WS WS WS
Electrofishing
Set Line WS WS
Trotline WS WS
Seine WS
Underwater Video WS WS WS WS
DIDSON
March 18-26 Habitat Type
Gear Type Tributary Tributary
Mouth
Upland
Slough
Side
Slough
Slough
Mouth
Side
Channel
Main
Channel
Other off-
channel
Minnow Trap WS WS WS WS WS WS, 8A WS
Electrofishing WS WS WS 8A
Set Line WS
Trotline WS
Seine
Underwater Video WS WS WS WS
DIDSON WS WS WS WS
April 7-13 Habitat Type
Gear Type Tributary Tributary
Mouth
Upland
Slough
Side
Slough
Slough
Mouth
Side
Channel
Main
Channel
Other
off-
channel
Minnow Trap WS WS WS, 8A WS WS, 8A
Electrofishing WS WS, 8A 8A
Set Line
Trotline
Seine
Underwater Video WS WS 8A 8A
DIDSON
WS: FA-104 (Whiskers Slough)
8A: FA-128 (Slough 8A)
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Table 4.2-1. Monitoring efficiency (percent operational) of LGL operated fixed-station receivers in the Susitna River drainage in 2013, by week. Percentages were calculated as the number of hours of recorded receiver activity divided by the number of hours in the week; "-" = 'not deployed'. Receivers were considered active in a given hour if at least one fish detection, beacon hit, or noise event was recorded during the hour. Data are preliminary as of Setember 9, 2013).
Fixed Station Location
Week
Montana
Creek (PRM 81) Middle River PRM 102 Whiskers
Creek
(PRM 105)
Lane Creek
(PRM 117)
Gateway
(PRM 130)
4th of July
Creek
(PRM 134)
Indian River
(PRM 142)
Upper Indian
River
Powerline
(PRM 146) Devils Canton PRM 153.9-166.1 Devils Island
(PRM 167)
6/2 - 6/8 1% 49% 73% 21% 2% 3% - - -
6/9 - 6/15 37% 100% 100% 100% 100% 100% - 64% -
6/16 - 6/22 100% 100% 100% 100% 100% 100% - 100% -
6/23 - 6/29 100% 100% 100% 100% 53% 100% - 52% -
6/30 - 7/6 100% 100% 100% 100% 77% 100% 92% 78% -
7/7 - 7/13 100% 100% 100% 100% 100% 100% 100% 68% -
7/14 - 7/20 100% 100% 100% 100% 100% 100% 100% 49% -
7/21 - 7/27 100% 100% 100% 100% 100% 100% 100% 64% 88%
7/28 - 8/3 100% 100% 100% 100% 100% 100% 100% 100% 100%
8/4 - 8/10 100% 100% 100% 100% 100% 100% 100% 100% 100%
8/11 - 8/17 100% 100% 100% 100% 100% 38% 100% 100% 100%
8/18 - 8/24 80% 100% 97% 100% 100% 100% 9% 100% 54%
8/25 - 8/31 0% 38% 0% 52% 54% 54% 0% 53% 14%
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Table 4.2-2. Summary of aerial surveys of radio-tagged fish in the Upper Susitna River, 2013.
PRM Zone
From To #6-226-236-256-266-286-296-307-17-27-37-47-57-67-77-87-97-107-117-127-137-147-157-167-177-187-197-207-217-227-237-247-257-267-277-287-297-307-318-18-28-38-48-58-68-78-98-108-118-128-138-168-178-198-208-238-248-258-268-278-308-319-29-3 Little Susitna River --3
Beyond Confluence --4
Confluence - Yentna 3.5 32.4 5 H
Yentna River 32.4 -22 H H H H H H H H H
Yentna - Deshka 32.4 45.0 35 H H H H H H H H H H
Deshka River 44.9 -42 H H H H H H H H H H
Willow and Little Willow 52.2 55.6 53 H H H H H H H H H H H
Kashwitna River 64.7 -54 H H H H H H H H
Deshka - Kashwitna 45.0 64.7 55 H H H H H H H H H H H
Caswell area tribs 65.8 76.3 63 H H H H H H
Kashwitna - Montana 64.7 80.7 65 H H H H H H H H H H H
Montana Creek 80.9 -71 H H H H H H H H H H
Montana - Sunshine 80.7 88.5 75 H H H H H H H H H H H
Sunshine Creek 88.1 -76 H H H H
Rabideux Creek 87.4 -77 H H H H H H
Talkeetna River 101.0 -81 H H H H H H H H H H
Chulitna River 101.7 -83 H H H H H H H H
Sunshine - Talkeetna 88.5 102.3 85 H H H H H H H H H H H H
Talkeetna - Lane 102.3 116.8 95 H H H H H H H H H H H H H H H H
Whiskers Creek 104.8 -97 H H H H H H H H H H H H
Trib off zone 95 110.5 -98 H H H H H H H
Lane - Gateway 116.8 130.1 105 H H H H H H H H H H H H H H H H H H H H H H H H H
Lane Creek 117.1 -106 H H H H H H H H H H H H H
5th of July Creek 127.3 -108 H H H H H
Slough 8A 129.2 129.8 109 H H H H H H H H H H H
Gateway - 4th of July 130.1 134.3 111 H H H H H H H H H H H H H H H H H H H H H H H H
Slough 9 131.4 133.5 112 H H H H H H H H H H H
Sherman Creek 134.1 -114 H H H H H
MOB - 4th of July Creek 134.3 -116 H H H H H H H H H H H H H H H H H
MOB - 4th of July - Slough 11 134.3 140.2 117 H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Slough 11 138.6 -118 H H H H H H H H H H H
MOB - Gold Creek 140.1 -119 H H H H H H H H H H H
MOB - Slough11 - Indian 140.1 142.1 125 H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Indian trib 141.8 -132 H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Indian - Slough 21 142.1 145.7 135 H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Slough 21 145.1 145.6 136 H H H H H H H H H H H H H
MOB - above Powerline 145.7 146.0 138 H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - abv Powerline - Portage 146.0 152.3 145 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Jack Long Creek 148.2 -146 H H H H H H H H H H H H H H H H
MOB - Portage trib 152.3 -152 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Portage - Impediment1 152.3 155.2 153 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Impediment1 - Cheechako 155.2 157.4 157 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Cheechako Creek 155.9 -158 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Cheechako - Impediment2 157.4 160.2 163 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Impediment2 - Chinook 160.2 160.5 167 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Chinook Creek 160.4 -168 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Chinook - Impediment3 160.5 164.8 173 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Devil Creek 164.8 -176 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Impediment3 - Devil Stn 164.8 166.9 177 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Devil Stn - Fog 166.9 179.4 185 H H H H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Fog Creek 179.3 -192 H H H H H H H H
MOB - Fog - Dam Site 179.4 186.8 195 H H H H H H H H H H H H H H H H H H H H H H H H H
MOB - Tsusena Creek 184.5 -197 H H H H H H H H H H H H H H H H H H
Survey Date
Zone Name
Middle River (PRM 102.4)
Upper Extent Devils Canyon (PRM 166.1)
Lower Extent Devils Canyon (PRM 153.9)
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Table 4.5-1. Summary of PIT tagging effort in the Middle and Lower River Study Area, 2013.
Species Life Stage Tag Type N Median Length (mm) Length Range (mm)
Chinook salmon Juvenile PIT 1,696 89 60-197
chum salmon Juvenile PIT 13 75 61-103
coho salmon Juvenile PIT 2,092 82 53-151
sockeye salmon Juvenile PIT 81 66 60-95
Pacific salmon, undifferentiated Juvenile PIT 67 70 60-122
Arctic grayling Adult PIT 29 349 330-477
Arctic grayling Juvenile-or-adult PIT 99 278 197-328
Arctic grayling Juvenile PIT 250 98 61-189
burbot Adult PIT 14 547 500-645
burbot Juvenile-or-adult PIT 92 400 287-493
burbot Juvenile PIT 117 135 87-275
Dolly Varden Juvenile-or-adult PIT 53 141 83-396
Dolly Varden Juvenile PIT 17 74 61-81
longnose suckera Adult PIT 2 380 350-410
longnose suckera Juvenile-or-adult PIT 6 289 270-340
longnose suckera Juvenile PIT 3 177 157-181
rainbow trout Adult PIT 55 390 330-538
rainbow trout Juvenile-or-adult PIT 94 247 202-325
rainbow trout Juvenile PIT 160 144 60-198
salmonid Juvenile PIT 2 100 93-106
whitefish, humpback Adult PIT 5 394 364-400
whitefish, humpback Juvenile-or-adult PIT 23 293 280-350
whitefish, humpback Juvenile PIT 58 241 78-279
whitefish, round Unknown PIT 1 Unknown -
whitefish, round Adult PIT 23 344 320-450
whitefish, round Juvenile-or-adult PIT 97 257 199-318
whitefish, round Juvenile PIT 179 100 68-196
whitefish, undifferentiated Adult PIT 1 424 -
whitefish, undifferentiated Juvenile-or-adult PIT 22 248 202-350
whitefish, undifferentiated Juvenile PIT 134 104 75-198
a: not a target species for PIT tagging
Note: All data are provisional and subject to ongoing QA/QC
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Table 4.5-2. Summary of fishes radio-tagged in the Middle and Lower River Study Area, 2013.
Species Tag Type N Median
Length (mm) Length Range (mm)
Arctic grayling Radio 35 325 276-416
Burbot Radio 9 409 335-676
Dolly Varden Radio 9 330 290-384
Longnose sucker Radio 28 336 269-402
Northern pike Radio 5 580 492-642
Rainbow trout Radio 44 387 265-500
Humpback whitefish Radio 7 297 284-409
Round whitefish Radio 21 331 278-428
Table 4.5-3. Radio tag allocation by season, Middle and Lower Susitna River, 2013.
Middle-Lower Susitna River, 2013
Species May/June July August Sept Total Live b
Arctic grayling 11 (0a) 17 (10) 1 (10) 6 (10) 35 (30) 9
Burbot 2 (10) 0 (10) 5 (10) 2 (10a) 9 (30) 3
Dolly Varden 1 (10) 6 (10) 2 (10a) 0 (0) 9 (30) 4
Longnose sucker 13 (10) 8 (10) 6 (10) 1 (10) 28 (30) 2
Northern pike 0 (10) 0 (10) 5 (10) 0 (10) 5 (30) 4
Lake trout 0 (10) 0 (10) 0 (10) 0 (10) 0 (30) 0
Rainbow trout 11 (0a) 17 (10) 3 (10) 13 (10) 44 (30) 20
Humpback whitefish 3 (10) 4 (10) 0 (10a) 0 (0) 7 (30) 2
Round whitefish 11 (10) 3 (10) 0 (10a) 7 (0) 21 (30) 10
Format: tags applied (target number of tags).
a FERC recommended tagging (n≥10) periods. Tagging during spawning periods conducted at the discretion of the surgeon as based on fish
condition.
b Live tags as of aerial survey on January 29, 2014. Data subject to ongoing evaluation of tag status.
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Table 4.8-1. Summary of size-at-life stage index used to classify Susitna River species, 2013.
Species Life stage Source Juvenile Juvenile-or-adult Adult
Chinook salmon alevin, fry, parr, smolt index
chum salmon alevin, fry, parr, smolt index
coho salmon alevin, fry, parr, smolt index
pink salmon alevin, fry, parr, smolt index
sockeye salmon alevin, fry, parr, smolt index
Alaska blackfish <42 42–113 >113 Buckwalter et al. 2012
Arctic grayling <190 190–328 >328 Buckwalter et al. 2012
Arctic lamprey <125 125-219 >219 Heard 1966; Docker 2009; Vladykov and Kott 1978
burbot <280 280–498 >498 Buckwalter et al. 2012
Dolly Varden <83 >83 - Buckwalter et al. 2012
eulachon Not Applicable
longnose sucker <188 188–348 >348 Buckwalter et al. 2012
northern pike <330 330–448 >448 Buckwalter et al. 2012
sculpin (slimy) <51 51–68 >68 Buckwalter et al. 2012
threespine stickleback <40 40-70 >70 ADFG 1981
lake trout <300 300-430 430 Burr 1993
rainbow trout <200 200-325 >325 Russell 1977, Adams 1999
Bering cisco Not Applicable
humpback whitefish <280 280–363 >363 Buckwalter et al. 2012
round whitefish <199 199–318 >318 Buckwalter et al. 2012
Whitefish,
undifferentiated <199 199-363 >363
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Table 4.8-2. Summary of fish with length and weight measurements collected in the Upper, Middle and, Lower Susitna River by hydrologic segment, 2013.
Species
Hydrologic Segment
Lower River Middle River Upper River Total
Chum salmon 60 56 116
Chinook salmon 672 1,366 123 2,161
Coho salmon 487 2,820 3,307
Pink salmon 7 39 46
Sockeye salmon 253 199 452
Pacifc salmon, undifferentiated 44 77 121
Arctic grayling 38 889 1,652 2,579
Burbot 152 280 85 517
Dolly Varden 13 167 299 479
Lamprey 123 19 142
Longnose sucker 661 560 126 1,347
Northern pike 44 44
Salmonid, undifferentiated 4 1 5
Sculpin 679 2,129 2,596 5,404
Stickleback, ninespine 140 140
Stickleback, threespine 884 457 1,341
Stickleback, undifferentiated 3 48 51
Trout, lake 1 1
Trout, rainbow 142 349 491
Whitefish, Bering cisco 2 2
Whitefish, round 108 472 173 753
Whitefish, humpback 8 102 8 118
Whitefish, undifferentiated 52 317 20 389
Grand Total 4,572 10,350 5,084 20,006
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Table 4.8-3. Summary of PIT tagging efforts and recaptures for the Susitna River, 2013.
Species Implanted Recaptured and Measured
N N %
Chinook salmon 1,696 44 3%
chum salmon 13 0 0%
coho salmon 2,092 76 4%
sockeye salmon 81 5 6%
Pacific salmon,
undifferentiated 67 1 1%
Arctic grayling 378 2 1%
burbot 223 8 4%
Dolly Varden 70 1 1%
longnose sucker 11 0 0%
rainbow trout 309 3 1%
salmonid 2 0 0%
whitefish, humpbackb 86 1 1%
whitefish, round 300 1 0%
whitefish, undifferentiated 157 1 1%
Total 5,485 143 3%
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4.8-4. Fish sample size used in condition factor assessment for the Middle and Lower Susitna River.
Chinook Salmon Arctic Grayling
Lower River
LR-1 61 8
LR-2 50 7
LR-3 144 15
LR-4 33 3
LR-5 1
Middle River
MR-1 87
MR-2 1 343
MR-5 3 25
MR-6 182 28
MR-7 132 5
MR-8 313 69
Tsusena Creek 9
Total 919 600
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Table 4.10-1. Summary of Fish Distribution and Abundance tissue collection for genetic baseline development, 2013.
Species Geomorphic Reach Grand Total
MR-1 MR-2 Devils Canyon MR-5 MR-6 MR-7 MR-8 LR-1 LR-2 LR-3 LR-4 Chinook
salmon
2 27 7 12
48
Coho salmon
5 39
44
Sockeye
salmon
2
2
Paficic
salmon,
unidentified
4
4
Arctic grayling 30 66 1 4 2
4 2 8 4 121
Arctic lamprey
9 9
Burbot 4 5 9 15 23 20 7 1 14 26 124
Dolly Varden
1
1 2 2
6
Longnose
sucker 7 15 3 4 14 19 5 2 20 16 105
Ninespine
stickleback
8 2 10
Northern Pike
18 18
Rainbow trout
5 5 3 4 6 1 1
25
Sculpin 27 25
44 14
7 25 8 6 156
Whitefish,
Bering cisco
1
1 2
Whitefish,
round 22 14 22 14 1 3 7 16 11 2 112
Whitefish,
humpback
4 2
7 13
Grand Total 90 126 42 117 75 98 38 50 72 91 799
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Table 4.11-1 Summary of fish collection for gut sampling, 2013.
Sampling
site Habitat Type Juvenile
Chinook
Juvenile
Coho
Juvenile
Rainbow
Adult
Rainbow Total Station
FA-184
(Watana Dam) RP-184-2 Side Channel 0 0 0 0 0
RP-184-3 Main Channel 0 0 0 0 0
FA-173
(Stephan Lake
Complex)
RP-173-1 Tributary Mouth 0 0 0 0 0
RP-173-2 Main Channel 0 0 0 0 0
RP-173-3 Side Channel 0 0 0 0 0
RP-173-4 Side Slough 0 0 0 0 0
Devils Canyon PRM 153.9 -166.1
FA-141
(Indian River) RP-141-1 Tributary Mouth 19 24 0 11 54
RP-141-3 Multi Split Main
Channel 0 0 0 0 0
FA-104
(Whiskers Slough)
RP-104-1 Side Slough 24 16 0 11 51
RP-104-2 Side Slough 10 17 0 9 36
RP-104-3 Main Channel 0 0 0 0 0
RP-104-4 Upland Slough 9 13 0 0 22
RP-104-5 Side Channel 11 17 0 0 28
Total 73 87 0 31 191
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Table 5.1-1. Summary of fish distribution by Geomorphic Reach the in Middle and Lower Susitna River, 2013. Includes the following data sources: Early-Life History sampling (ELH), habitat stratified randomized sampling (GRTS), direct tributary sampling (Direct), rotary screw trap (RST), resident fish catch at Curry fishwheel (PRM 124), opportunistic
sampling (Opportunistic), targeted sampling for radio tagging (RT) river productivity sampling (RP), and habitat
suitability criteria sampling (HSC).
Locationa PRM Chinook salmon Chum salmon Coho salmon Pink salmon Sockeye salmon Salmon, undifferentiated Arctic Grayling Burbot Dolly Varden Lake Trout Lamprey Longnose sucker Northern Pike Rainbow trout Sculpin Stickleback, ninespine Stickleback, threespine Whitefish, Bering cisco Whitefish, humpback Whitefish, round Whitefish, undifferentiated Upper River
Study Area
187.1-
234.5 X X X X X X X X X X
Proposed Watana Dam (PRM 187.1)
MR-1a
184.6-
187.1 X X X X X X X
MR-2b
169.6-
184.6 X X X X X X X X
Upper extent Devils Canyon (PRM 166.1)
MR-3c
166.1-
169.6 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
MR-4d
153.9-
166.1 X X
Lower extent Devils Canyon (PRM 153.9)
MR-5a
148.4-
153.9 X X X X X X X X X X X X X X X
MR-6a
122.7-
148.4 X X X X X X X X X X X X X X X X
MR-7a
107.8-
122.7 X X X X X X X X X X X X X X X X X
MR-8a
102.4-
107.8 X X X X X X X X X X X X X X X X X
LR-1a
87.9-
102.4 X X X X X X X X X X X X X X X X X
LR-2a
65.6-
87.9 X X X X X X X X X X X X X X X X X X
LR-3a
44.6-
65.6 X X X X X X X X X X X X X X X X X
LR-4a
32.3-
44.6 X X X X X X X X X X X X X X X X X X X
a Geomorphic reaches MR-1, MR-5, MR-6, MR-7, MR-8, LR-1, LR-2, LR-3, and LR-4 include sites located in the mainstem Susitna River and its associated off-
channel and tributary habitats within the Zone of Hydrologic Influence (ZHI). Directed sampling efforts outside of the ZHI did not occur in these reaches.
b Geomorphic reach MR-2 includes sites located in the mainstem Susitna River and its associated off-channel and tributary habitats within the Zone of Hydrologic
Influence (ZHI), as well as directed sampling efforts outside of the ZHI in Fog and Tsusena creeks.
c Geomorphic reach MR-3 was not sampled during on-the-ground surveys in 2013.
d Geomorphic reach MR-4 only includes directed sampling efforts outside of the ZHI in Chinook Creek. The mainstem Susitna River and its associated off-
channel and tributary habitats within the ZHI were not sampled during on-the-ground surveys in 2013.
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Table 5.1-2. Middle Susitna fish observations, 2013. Includes the following data sources: Early-Life History sampling (ELH), habitat stratified randomized sampling (GRTS), direct tributary sampling (Direct), rotary screw trap (RST), resident fish catch at fishwheels, opportunistic sampling (Opportunistic), targeted sampling for radio tagging (RT) river productivity sampling (RP), and habitat suitability criteria sampling (HSC).
Geomorphic Reach /PRM Habitat Sample Type Salmon, Chinook (adult) Salmon, Chinook (juvenile) Salmon, chum (adult) Salmon, chum (juvenile) Salmon, coho (adult) Salmon, coho (juvenile) Salmon, pink (adult) Salmon, pink (juvenile) Salmon, sockeye (adult) Salmon, sockeye (juvenile) Pacific salmon, (juvenile) undifferentiated Arctic grayling Burbot Dolly Varden Lamprey Longnose sucker Salmonid, undifferentiated Sculpin Stickleback, threespine Stickleback, undifferentiated Trout, rainbow Unknown species Whitefish, humpback Whitefish, round Whitefish, undifferentiated Total Proposed Watana Dam Location PRM 187.1
MR-1 / 184.6-187.1 Susitna River GRTS, RP
110 12 2
12
357
32 2 527
MR-2 169.6-184.6
Susitna River GRTS, RP 1 1
534 15 4
69
457
5
67 8 1,161
Susitna River: Off-Channel GRTS, RP
783 13 8
328
473
1
18 10 1,634
Tributary GRTS, RP, RT
62 4 2
3
103
1 175
Tsusena Creek Direct 1
74
4
25
3
107
Fog Creek Tributary ELH, Direct
10
30
40
Fog Creek ELH, Direct
315
95
1
411
Fog Creek: Off-Channel Direct
3
4
7
Upper Extent Devils Canyon PRM 166.1
MR-4 153.9-
166.1 Chinook Creek Direct
63
13
76
Lower Extent Devils Canyon PRM 153.9
MR-5 148.1-153.9
Susitna River GRTS 3 5 31
34 21 26
7 6 7 32 12
12 1 101
15 9 3 34 4 363
Susitna River: Off-Channel ELH, GRTS
106
17 1 1 5 4
3 2 2
81
162
10
6
400
MR-6
122.7-148.4
Susitna River ELH, RST, Fishwheel, GRTS, RT, HSC 4 180 67 68 42 585 312 1 3 92 46 297 57 16
326 5 555 2
43 25 36 134 297 3,193
Susitna River: Off-Channel ELH, GRTS, RP, HSC
597 222 1,022 4 1,099 3 1 191 1,495 47 179 103 10
289 59 816 3
24 11 38 55 367 6,635
Tributary ELH, GRTS, RT, Opportunisitic, HSC 12 147 276 16 24 637 3,312 2
28 22 195 4 57
9 28 427
50 11
11 4 5,272
Indian River RST, RT 10 567 85 150 47 1,745 655 411 2 289 37 78 3 23
25 2 294
103
7 25 7 4,565
MR-7 107.8-122.7
Susitna River ELH, GRTS, RT, HSC 2 30 20 20 3 54 92
2 20 9 29 36 3
186
368 1
8 12 1 34 15 945
Susitna River: Off-Channel ELH, GRTS, HSC
122 6
2,181 17 4
106 450 27 81 9
111 2 135 7,069 177 20 0 12 28 24 10,581
Tributary GRTS, HSC
28
48 634 90
28 3 12 33 15 5 18 33 155 3
76
2 1,183
MR-8 102.4-107.8
Susitna River RST, GRTS, RP, HSC 19 992 76 106 240 686 173 6 23 203 57 122 51 16 6 268 27 488 23
30 38 60 175 293 4,178
Susitna River: Off-Channel ELH, GRTS, RP, HSC
452 4 3 46 880
317 184 50 41 4 62 313 33 637 490 71 32 16 8 19 35 3,697
Tributary ELH, GRTS, RP, Opportunistic, HSC
179 5 9 66 199 2 1 3 6 3 78 5 8 6 9 5 94 13
46
2
739
Grand Total 52 3,300 898 1,394 554 8,738 4,683 427 236 2,594 865 2,665 472 574 79 2,059 195 5,789 7,604 248 457 129 165 643 1,069 45,889
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Table 5.1-3. Lower Susitna River fish observations, 2013. Includes the following data sources: Early-Life History sampling (ELH), mainstem transect sampling (Transect), rotary screw trap (RST), opportunistic sampling (Opportunistic), targeted sampling for radio tagging (RT) and river productivity sampling (RP).
Geomorphic Reach /PRM Habitat Sample Type Salmon, Chinook (adult) Salmon, Chinook (juvenile) Salmon, chum (adult) Salmon, chum (juvenile) Salmon, coho (adult) Salmon, coho (juvenile) Salmon, pink (adult) Salmon, pink (juvenile) Salmon, sockeye (adult) Salmon, sockeye (juvenile) Pacific salmon, (juvenile) undifferentiated Arctic grayling Burbot Dolly Varden Lamprey Longnose sucker Northern pike Sculpin, undifferentiated Stickleback, ninespine Stickleback, threespine Stickleback, undifferentiated Trout, rainbow Whitefish, Bering cisco Whitefish, humpback Whitefish, round Whitefish, undifferentiated Total LR-1 87.9-102.4
Susitna River Transect
6 34
4
3
1 2 2
5 1
92
106
1
12 19 288
Susitna River: Off-Channel Transect
13 181 18 52 15 2
2 279 3 2 18
5 8
38
76
4 4 720
Tributary ELH, Transect, Opportunsitic, RT 2 61 56 3 2 114 12
3 103 24 6 3 3 15 8
43 3 574 1 16
10
1,062
LR-2 65.6-87.9
Susitna River Transect, RP
7
1 1 16 1
3 8 4 7 2
126
152
6
10 1
20 3 368
Susitna River: Off-Channel Transect, RP
9
12
21
Montana Creek RST, Opportunstic, RT 3 1,302 32 825 9 207 400 6
20 2
23 10 1
72 2 150 14 95
4
3,177
Tributary ELH, Transect, RT, RP 1 61
18
29
1 1 4 2
9 7
186
24 1 7
10
361
LR-3 44.6-65.6
Susitna River Transect 1 43
2 1
16 2 12 13 1 11 129
123 2 1
4 6 367
Susitna River: Off-Channel ELH, Transect
67
2 1 168 1
18
1 4
6 40
12 115 1,794
14
7 1 2,251
Tributary ELH, Transect
52
7 1 13 1
2
3 3
26 11
112 1 17
4
7 1 261
LR-4 32.3-44.6
Susitna River Transect, RT
1 1
1
5 4 30
42 114
6
1
1 8 2 216
Susitna River: Off-Channel ELH, Transect
34
2 2 31
1 20 3 1 69
9 575 7 44 21 1,820 1 18 1 6 26 27 2,718
Tributary ELH, Transect, RT
10
4 55 3
6
1
79
Grand Total 7 1,655 304 877 72 607 422 6 7 444 78 39 154 30 133 1,115 62 897 144 4,469 17 165 2 8 112 63 11,889
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Table 5.1-4. Total fish count by gear type for three seasonal fish distribution and abundance sampling events in Middle River Focus Areas, 2013.
Species Life stage
Gear Type
Snorkel
Minnow
trap
Fyke
Net Seine
Backpack
Electrofish
Hoop
trap Angle
Boat
Electrofish
Dip
Net
Gillnet,
drift Trotline
Grand Total
Salmon, Chinook Adult 12 1 13
Salmon, Chinook Juvenile 65 459 179 234 17 2 31 987
Salmon, chum Adult 325 14 39 1 10 1 2 392
Salmon, chum Juvenile 6 15 6 27
Salmon, coho Adult 85 8 19 2 2 8 10 134
Salmon, coho Juvenile 1,169 1,631 816 524 125 23 8 4,296
Salmon, pink Adult 3,073 32 33 17 1 3,156
Salmon, sockeye Adult 48 8 8 64
Salmon, sockeye Juvenile 658 30 147 607 44 4 1,490
Salmon, undifferentiated Juvenile 212 80 350 17 5 1 6 3 674
Arctic grayling 610 16 145 296 204 7 25 6 1 1,310
Burbot 57 99 7 34 27 1 1 226
Dolly Varden 23 10 11 4 14 1 1 2 66
Lamprey 1 2 20 27 50
Longnose sucker 124 162 126 198 148 28 4 790
Salmonid, undifferentiated 51 1 1 53
Sculpin, undifferentiated 224 384 32 210 1,882 5 14 2,751
Stickleback, threespine 112 2,937 1,841 505 3 5,398
Trout, rainbow 49 37 59 9 9 5 11 8 3 190
Whitefish, humpback 2 15 17
Whitefish, round 4 8 37 113 24 2 15 203
Whitefish, undifferentiated 11 1 4 98 10 3 127
Grand Total 6,862 5,814 3,899 2,952 2,555 146 93 71 16 5 1 22,414
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Table 5.1-5. Total fish count by gear type during three seasonal fish distribution and abundance sampling events in the Middle River outside of Focus Areas, 2013.
Species Life stage
Gear Type Grand Total Minnow Trap Backpack Electrofish Snorkel Boat Electrofish Angle Fyke Net Seine
Salmon, Chinook Adult
1
1
Juvenile 37 7 9
2
55
Salmon, chum Adult
1 17
1 19
Juvenile 1 1
2
Salmon, coho Adult
4
4
Juvenile 666 198 20 1 5 6 1 897
Salmon, pink Adult
0 151 2 12
2 167
Juvenile
1
4
5
Salmon, sockeye Adult
45
10
55
Juvenile 17 41
5
3 66
Arctic grayling 5 171 83 88 19
366
Burbot 54 65
8
4 2 133
Dolly Varden 40 63 200
303
Lamprey
4
4
Longnose sucker 49 225 14 23
14 8 333
Salmonid, undifferentiated
55 1
56
Sculpin 214 1,146 4 11
1,375
Stickleback, threespine 1,812 155 27
1,994
Stickleback, undifferentiated 74 5 169
248
Trout, rainbow 21 13 12 6 4 10
66
Whitefish, humpback
9
9
Whitefish, round
41 3 71
4 6 125
Whitefish, undifferentiated
2
2
Grand Total 2,990 2,139 810 229 54 40 23 6,285
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Table 5.1-6. Total fish count by gear type during three seasonal fish distribution and abundance sampling events in the Lower River, 2103.
Species Life stage
Gear Type
Grand Total Minnow Trap Seine Hoop Trap Backpack Electrofishing Fyke Net Boat Electrofish Snorkel Angle Gillnet, drift Salmon, Chinook Adult 1 2 1 4
Salmon, Chinook Juvenile 50 59 65 20 17 1 212
Salmon, chum Adult 5 3 3 21 32
Salmon, chum Juvenile 4 16 2 3 1 26
Salmon, coho Adult 4 2 50 2 2 60
Salmon, coho Juvenile 70 36 80 17 67 270
Salmon, pink Adult 1 5 1 1 1 12 1 22
Salmon, sockeye Adult 1 1 2 1 5
Salmon, sockeye Juvenile 35 253 8 46 11 353
Salmon, undifferentiated Juvenile 1 2 29 1 33
Arctic grayling 2 18 3 6 4 3 36
Burbot 22 9 87 9 9 12 148
Dolly Varden 2 2 2 6
Lamprey 13 50 19 2 3 87
Longnose sucker 182 461 94 73 233 41 1,084
Northern pike 10 1 3 4 4 24 46
Sculpin, undifferentiated 103 80 15 474 2 674
Stickleback, ninespine 71 61 2 3 4 141
Stickleback, threespine 2,794 131 654 144 189 2 3,914
Stickleback, undifferentiated 1 1 2
Trout, rainbow 15 2 1 20 12 50
Whitefish, Bering cisco 1 1 2
Whitefish, humpback 1 1 5 1 8
Whitefish, round 24 45 15 6 5 1 96
Whitefish, undifferentiated 2 48 4 6 1 61
Grand Total 3,399 1,236 1,087 852 563 106 93 32 4 7,372
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Table 5.2-1. Middle and Lower River rotary screw trap catch at Indian River, Susitna River at Curry Station, Susitna River at Talkeetna Station, and Montana Creek, 2013.
Location Geo Reach PRM Chinook salmon Chum salmon Coho salmon Sockeye salmon Pink salmon Pacific salmon, undifferentiated Arctic grayling Burbot Dolly Varden Lamprey, undifferentiated Longnose sucker Rainbow trout Salmonid, undifferentiated Sculpin, undifferentiated Threespine stickleback Whitefish, humpback Whitefish, round Whitefish, undifferentiated Total Adult Juvenile Adult Juvenile Adult Juvenile Adult Juvenile Adult Juvenile Indian River MR-6 142.1 9 567 85 150 47 1,745 2 289 655 411 37 72 3 23
20 101 2 294
7 25 7 4,551
Susitna River at Curry Station MR-6 124 1 133 14 42 23 541 2 18 189 1 31 99 7 5
42 13
14 2 26 28 196 1,427
Susitna River at Talkeetna Station MR-8 106.9 17 873 50 91 240 375 23 63 158 6 23 106 16 8 3 96 19 18 45 1 52 143 270 2,696
Montana Creek LR-2 80.8 3 1,254 32 799 9 189
400 6 10 2
22 10 1 80
20 20
4
2,861
Total 30 2,827 181 1,082 319 2,850 27 370 1,402 424 101 279 26 58 13 159 213 20 373 23 85 200 473 11,535
Table 5.2-2. Smolt to parr ratios for juvenile salmon caught in Middle and Lower River rotary screw traps, 2013.
Species Indian River Susitna @ Curry Station Susitna @ Talkeetna Station Montana Creek
Chinook salmon 3:1 0.2:1 40:1 5:1
Chum salmon 8:1 - 14:1 22:1
Coho salmon 0.5:1 0.01:1 2:1 2:1
Sockeye salmon 7:1 - 49:1 -
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Table 5.2-3. Number of fish in the Middle and Lower Susitna River implanted with PIT tags in 2013, detected by stationary antennas, and recaptured during subsequent sampling events, by target species.
Species
Implanted Detected at Antenna Recaptured Total Resighteda
N N % N % N %
Chinook salmon 1,696 187 11% 44 3% 223 13%
chum salmon 13 0 0% 0 0% 0 0%
coho salmon 2,092 286 14% 76 4% 352 17%
sockeye salmon 81 5 6% 5 6% 8 10%
Arctic grayling 378 41 11% 2 1% 42 11%
burbot 223 25 11% 8 4% 32 14%
Dolly Varden 70 9 13% 1 1% 10 14%
longnose sucker 11 0 0% 0 0% 0 0%
rainbow trout 309 73 24% 3 1% 74 24%
whitefish, humpbackb 86 1 1% 1 1% 1 1%
whitefish, round 300 22 7% 1 0% 23 8%
Total 5,259 649 12% 141 3% 765 15%
Note: Values exclude a small number of PIT tags with missing implant records, multiple implant records, or inconsistent species identification upon recapture.
a Includes fish that were either detected at PIT antennas or recaptured. This includes 25 fish that were both recaptured and detected at an antenna.
b The lone humpback whitefish detected and recaptured in the Middle River (PIT tag 000183327483) was tagged and released in the Upper River at the
Oshetna River rotary screw trap.
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Table 5.2-4. Summary of PIT tag detections by species at the four stationary antenna arrays in the Middle and Lower Susitna River study area, 2013.
Species
Indian River
(PRM 142.1)
Slough 8A
(PRM 129)
Whiskers Slough
(PRM 105)
Montana Cr. (PRM 80.8) Total
Fish Detectionsa Fish Detectionsa Fish Detectionsa Fish Detectionsa Fish Detectionsa
Chinook
salmon 19 103 5 103 109 3,416 54 675 187 4,297
coho salmon 72 1,744 14 1,749 191 36,315 13 424 286b 40,232
sockeye
salmon 1 3 4 15 5 18
Pacific salmon,
undifferentiated 10 1,954 10 1,954
Arctic grayling 8 68 1 4 25 1,423 8 40 41c 1,535
burbot 9 511 16 2,237 25 2,748
Dolly Varden 4 17 1 42 3 45 1 7 9 111
humpback
whitefish 1 1 1 1
rainbow trout 13 73,134 3 75 44 850 13 134 73 74,193
round whitefish 4 41 5 90 12 1,016 1 2 22 1,149
whitefish,
undifferentiated 1 2 3 90 1 21 5 113
Total 122 75,112 42 2,589 404 45,393 101 3,257 664 126,351
Note: Values exclude a small number of PIT tags with missing implant records, multiple implant records, or inconsistent species identification upon
recapture.
a “Detections” reflects the number of unique records for a given fish encounter with an antenna; each “detection” is typically comprised of many consecutive readings of the PIT tag by the antenna reader.
b Includes four coho salmon detected at the Whiskers Slough antenna and either the Slough 8A antenna or the Indian River antenna.
c Includes one Arctic grayling detected at both the Indian River and Montana Creek antennas.
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Table 5.2-5. Juvenile Chinook salmon movement between macrohabitat types in the Middle and Lower River in 2013 based on a comparison of initial tagging events versus subsequent recapture or detection at PIT antennas. Values indicate the number of individual fisha.
Detection/Recapture Macrohabitat
Main Channel Off-Channel Tributary
Main Channel Side Channel Split Main Channel Total Side Slough SS Beaver Complex US Beaver Complex Total Not Reported Single Channel Split Channel Tributary Mouth Total Tagging Macrohabitat Main Channel Main Channel 1 1 2 8 8 2 2
Side Channel 1 1 23 23
Split Main Channel 1 1
Total 2 2 4 31 31 2 2 Off-Channel Side Slough 26 26
SS Beaver Complex 3 1 4
US Beaver Complex 6 9 15
Total 36 2 7 45 Tributary Not Reported 7 7
Single Channel 44 44 1 57 58
Split Channel 2 2
Tributary Mouth 1 2 3 4 4 18 10 28
Total 1 2 3 48 48 1 64 20 10 95
a Values include fish that may have been detected or recaptured in multiple habitat types.
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Table 5.2-6. Juvenile coho salmon movement between macrohabitat types in the Middle and Lower River in 2013 based on a comparison of initial tagging events versus subsequent recapture or detection at PIT antennas. Values indicate the number of individual fisha.
Detection/Recapture Macrohabitat
Main Channel Off-Channel Tributary
Main Channel Split Main Channel Total Side Slough SS Beaver Complex US Beaver Complex Total Single Channel Split Channel Tributary Mouth Total Tagging Macrohabitat Main Channel Main Channel 3 3 34 34
Side Channel 7 7
Split Main Channel 3 3 61 5 66
Total 3 3 6 102 5 107 Off-Channel Side Slough 11 11
SS Beaver Complex 8 1 9
Upland Slough 1 1
US Beaver Complex 18 31 49
Total 38 1 31 70 Tributary Complex Channel 3 3 3 3
Single Channel 31 31 20 8 28
Split Channel 1 1
Tributary Mouth 3 3 6 30 3 33 69 8 77
Total 3 3 6 64 3 67 20 81 8 109
a Values include fish that may have been detected or recaptured in multiple habitat types.
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Table 5.3-1. Total count of juvenile anadromous and resident fish captured during Early Life History sampling in the Middle and Lower Susitna River.
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Table 5.3-2. Number of juvenile salmon fry (fork length <50mm) observed during three Early Life History sampling events (April 28 to May 3, June 1 to June 12, and June 20 to June 29) in the Middle and Lower Susitna River, 2013.
Sampling gear types included dipnetting = DP, backpack electrofishing = EF, fyke netting = FK, minnow trapping = MT,
seining = SN, snorkeling =SK.
Location Geomorphic ReachProject River MileSampling EventNumber of SitesGear Types Chinook salmonChum salmonCoho salmonPink salmonSockeye salmonGrand Total2 3 EF 0
3 4 EF 0
2 6 EF, MT, SN 0
3 6 EF, FK, MT 0
2 6 MT, EF 2 3 1 2 8
3 6 EF, FK, MT 30 6 2 2 40
1 2 EF 18 18
2 6 DP, EF, MT, SK 321 175 496
3 6 EF, FK, MT, SK 14 674 16 704
1 5 EF, MT 27 27
2 6 EF, FK, MT 1 15 2 18
3 6 EF, FK, MT, SN 2 2
2 6 FK, MT 7 18 11 1 37
3 6 FK, MT, SN 1 1 2
1 3 EF 2 9 1 12
2 6 EF, MT 1 1 1 1 4
3 6 FK, MT, SK 8 2 3 13
2 1 EF, MT 4 4
3 2 MT, SN 9 44 46 99
Sunshine Creek LR-1 89 3 1 EF 0
Rabideux Creek LR-1 88 3 1 EF, SN 1 1 25 27
Montana Creek LR-2 77 3 1 EF 5 4 9
Goose Creek LR-2 76 3 1 EF 4 12 2 18
2 2 EF, MT 1 1
3 1 MT 1 1
197.5 Creek LR-3 63 2 1 EF 7 7
2 1 MT 0
3 1 MT 5 5
LR-52-US LR-3 52 3 1 EF 1 3 4
2 2 EF, MT 1 1
3 2 EF, MT 0
10 2 27 1 0 27 57
46 11 365 15 2 183 576
51 76 702 53 2 87 920
Grand Total 89 1094 69 4 297 1553
All Sites
Event 1
Event 2
Event 3
Little Willow Creek LR-3 56
Fish Creek LR-4 34
Trapper Creek LR-1 100
LR-63.5-US LR-3 64
FA-113 (Oxbow I)MR-6 113
FA-104 (Whiskers Slough) MR-6 104
Lower River
Fog Creek MR-2 179
FA-144 (Slough 21)MR-6 144
FA-141 (Indian River)MR-6 141
FA-138 (Gold Creek)MR-6 138
FA-128 (Slough 8A)MR-6 128
Proposed Watana Dam Site PRM 187.1
Devils Canyon PRM 153.9-166.1
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Table 5.3-3. Average fork length of juvenile salmon fry (fork length <50mm) caught during Early Life History sampling in the Middle and Lower Susitna River.
Location Geomorphic ReachProject River MileSampling EventChinook salmonChum salmonCoho salmonPink salmonSockeye salmonFog Creek MR-2 179
FA-144 (Slough 21)MR-6 144
2 35 34.7 45 33
3 39.8 44.5 44 36
1 33.6
2 31
3 37.4 31.2 31
1 35
2 43 33.4 46
3 37
2 36 36.7 27
3 38 36
1 45 34.2 47
2 39 39 34 36
3 42.4 34 44
2 32
3 39 37.6 41.3
Sunshine Creek LR-1 89
Rabideux Creek LR-1 88 3 35 39 34
Montana Creek LR-2 77 3 47 42.5
Goose Creek LR-2 76 3 44.8 39.7 41
2 34
3 47
197.5 Creek LR-3 63 2 36.9
Little Willow Creek LR-3 56 3 43.6
LR-52-US LR-3 52 3 45 35
Fish Creek LR-4 34 2 30
MR-6 141
FA-128 (Slough 8A)MR-6 128
FA-138 (Gold Creek)MR-6 138
Proposed Watana Dam Site PRM 187.1
Devils Canyon PRM 153.9-166.1
Lower River
LR-63.5-US LR-3 64
Trapper Creek LR-1 100
FA-104 (Whiskers Slough) MR-6 104
FA-113 (Oxbow I)MR-6 113
FA-141 (Indian River)
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Table 5.5-1. PIT tag recaptures for pilot species fish used for growth assessment in the Middle and Lower River, 2013.
Species Implanted (N) Detected (N) Recaptured (N) Number with Sufficient Duration (>7 days)
Chinook salmon 1,696 187 44 13
Arctic grayling 377 41 2 0
Total 2,073 228 46 13
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Table 5.5-2. Specific growth rates of juvenile Chinook salmon in the Middle and Lower River, 2013. Only fish with a minimum of eight days duration between recapture events were used for growth assessment.
River Reach Stream Name
ISR
Habitat Channel Category ISR Macro Habitat Implant Date Implant Length Recapture Date Recapture Length Duration (d)
Length Change (mm) Growth (mm/d)
SGR (% length /day)
ML MR-8 Susitna River
Main
Channel Main Channel 15-Sep-13 125 23-Sep-13 125 8 0 0.00 0.00
ML MR-8 Susitna River OCH
Upland Slough
Beaver Complex 31-Aug-13 78 23-Sep-13 80 23 2 0.09 0.11
ML MR-6 Susitna River OCH
Side Slough
Beaver Complex 09-Aug-13 90 25-Sep-13 102 47 12 0.26 0.27
ML MR-6 Susitna River OCH
Upland Slough
Beaver Complex 25-Jul-13 91 30-Aug-13 105 36 14 0.39 0.40
ML MR-6 Susitna River OCH
Upland Slough
Beaver Complex 24-Jul-13 104 30-Aug-13 119 37 15 0.41 0.36
ML MR-6 Susitna River OCH
Upland Slough
Beaver Complex 24-Jul-13 108 30-Aug-13 125 37 17 0.46 0.40
ML MR-8 Susitna River OCH
Upland Slough
Beaver Complex 03-Sep-13 111 26-Sep-13 113 23 2 0.09 0.08
ML MR-6 Susitna River OCH
Upland Slough
Beaver Complex 24-Jul-13 116 30-Aug-13 131 37 15 0.41 0.33
ML MR-6 Susitna River OCH
Upland Slough
Beaver Complex 30-Aug-13 131 27-Sep-13 132 28 1 0.04 0.03
ML MR-6 Indian River Trib Trib Mouth 08-Jul-13 89 17-Jul-13 92 9 3 0.33 0.37
ML LR-2 Montana Creek Trib Single Channel 07-Jul-13 82 25-Jul-13 90 18 8 0.44 0.52
ML MR-8 Whiskers Creek Trib Single Channel 22-Jul-13 69 20-Sep-13 77 60 8 0.13 0.18
ML MR-8 Whiskers Creek Trib Single Channel 20-Jul-13 84 28-Aug-13 97 39 13 0.33 0.37
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Table 5.5-3. Condition factors for juvenile Chinook salmon captured in the Middle and Lower River, 2013.
MIDDLE RIVER
Macro
Habitat Segment Sample Size Mean
Mean Standard
Error
MC MR 3 1.32 0.105
SMC MR 3 1.18 0.049
SC
MR 94 1.00 0.013
MR-6 9 1.08 0.047
MR-7 24 0.88 0.028
MR-8 61 1.03 0.012
SS
MR 86 1.02 0.016
MR-6 2 1.11 0.121
MR-8 84 1.02 0.016
SSB
MR 35 1.09 0.020
MR-6 30 1.08 0.022
MR-7 5 1.13 0.059
US
MR 32 1.07 0.040
MR-6 3 1.59 0.242
MR-7 15 1.00 0.032
MR-8 14 1.02 0.021
USB
MR 246 1.02 0.008
MR-6 94 1.01 0.012
MR-7 58 1.04 0.020
MR-8 94 1.02 0.011
BW MR 11 0.97 0.072
Trib
MR 111 1.02 0.018
MR-6 24 1.00 0.059
MR-7 27 0.98 0.017
MR-8 60 1.04 0.022
Trib
Mouth MR 7 1.09 0.036
CWP MR 3 1.06 0.033
LOWER RIVER
Macro Habitat Segment Sample Size Mean
Mean Standard
Error
MC LR 2 0.95 0.100
SC LR 30 1.12 0.024
SS LR 2 0.95 0.10
US
LR 58 1.10 0.020
LR-3 35 1.10 0.025
LR-4 23 1.20 0.032
USB LR 30 0.94 0.043
Trib
LR 111 1.12 0.022
LR-1 48 1.08 0.023
LR-2 35 1.21 0.048
LR-3 28 1.09 0.042
Trib
Mouth LR 5 1.04 0.063
CWP
LR 50 1.09 0.028
LR-1 7 1.06 0.065
LR-2 4 1.39 0.226
LR-3 30 1.09 0.026
LR-4 9 0.97 0.027
LR-4 9 0.97 0.027
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Table 5.5-4. Condition factors for Arctic grayling captured in the Middle and Lower River, 2013..
MIDDLE RIVER
Macro
Habitat Segment
Sample
Size Mean
Mean Standard
Error
MC
MR 97 0.92 0.018
MR-1 48 0.90 0.026
MR-2 22 0.87 0.042
MR-5 20 0.97 0.032
MR-6 1 1.17 n/a
MR-7 2 0.90 0.080
MR-8 4 0.94 0.071
SMC MR 25 0.82 0.033
SC
MR 97 0.91 0.018
MR-1 39 0.94 0.019
MR-2 53 0.89 0.029
MR-6 1 0.93 n/a
MR-8 4 0.88 0.08
SS
MR 106 0.86 0.02
MR-2 80 0.87 0.02
MR-5 3 0.73 0.068
MR-6 7 0.84 0.11
MR-8 16 0.83 0.030
SSB MR 1 0.74 n/a
US MR n/a n/a n/a
BW MR 50 0.63 0.027
Trib
MR 55 0.83 0.011
MR-6 1 0.87 n/a
MR-8 45 0.83 0.012
Tsusena
Creek 9 0.83 0.029
Trib
Mouth MR 13 0.77 0.056
CWP
MR 122 0.89 0.016
MR-2 111 0.88 0.017
MR-6 11 0.99 0.069
LOWER RIVER
Macro
Habitat Segment
Sample
Size Mean
Mean Standard
Error
MC LR 1 0.92 n/a
SMC LR 1 0.81 n/a
SC LR 15 0.96 0.051
SS LR 3 0.94 0.093
US LR 1 0.90 n/a
Trib LR 6 0.74 0.036
Trib
Mouth LR 1 0.94 n/a
CWP LR 6 0.96 0.051
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Table 5.6-1. Northern pike habitat associations by life stage, 2013.
Table 5.6-2 Angling CPUE for northern pike in Lower River geomorphic reach-4 during fish distribution and abundance sampling, 2013.
Juvenile Adult
Clearwater plume Clearwater plume 2 4 6
Side slough Run 1 0 1
Glide 12 30 42
Pool 0 8 8
Total 15 42 57
Macrohabitat Mesohabitat Life Stage Total
Tributary
Season
Transect
PRM Habitat Macrohabitat Mesohabitat
Total Angling
Effort (min)
Cast
Count
Northern Pike
Caught
CPUE
(catch/hour^1)
CPUE
(catch/50 casts)
Early Summer 41.4 Off-channel Side Slough Glide 54 51 0 0 0
Late Summer 34 Tributary Tributary Glide 280 250 22 4.7 4.4
Fall 34 Tributary Tributary Glide 131 30 2 0.9 3.3
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FIGURES 10.
Figure 3-1. Upper Susitna River fish distribution and abundance study area.
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Figure 4.1-1. Spring early life history (ELH) sampling locations in the Middle and Lower Susitna River, 2013
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Figure 4.1-2. Fish distribution and abundance sampling transects in the Lower Susitna River, 2013.
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Figure 4.1-3. Outmigrant trap, PIT tag interrogation system, and radio fixed receiver locations in the Middle Susitna River, 2013
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Figure 4.2-1. Summary of PIT tag interrogation system operation in the Middle and Lower Susitna River, 2013.
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Figure 4.2-2. Rotary screw trap operation in the Middle Susitna River and in Indian River (PRM 142.1) and Montana Creek (PRM 80.8), 2013.
1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 15-Aug 30-Aug 14-Sep 29-Sep 14-Oct
Indian River (PRM 142.1)
Trap damaged, replaced
with Curry trap
Trap not fished
due to high
debris load
0
50
1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 15-Aug 30-Aug 14-Sep 29-Sep 14-Oct Susitna Gold Creek (kcfs) Susitna River at Curry Station (PRM 124)
0
50
1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 15-Aug 30-Aug 14-Sep 29-Sep 14-Oct Susitna Gold Creek (kcfs) Susitna River at Talkeetna Station (PRM 106.9)
Trap not fished due to
high debris load
1-Jun 16-Jun 1-Jul 16-Jul 31-Jul 15-Aug 30-Aug 14-Sep 29-Sep 14-Oct
Montana Creek (PRM 80.8)
Trap reinstalled
following flood
event
Trap not fished due to
high debris load
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Figure 4.8-1. Condition factor of juvenile Chinook salmon (top) and Arctic grayling (bottom) as a function of length, 2013.
0
0.5
1
1.5
2
2.5
0 20 40 60 80 100 120 140 160 180 200Condition FactorLength (mm)
Chinook Salmon
0
0.5
1
1.5
2
2.5
3
0 50 100 150 200 250 300 350 400 450 500Condition FactorLength (mm)
Arctic Grayling
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Figure 5.2-1. Juvenile salmon catch by life stage at the Indian River rotary screw trap (PRM 142.1), 2013. Species and lifestage codes SAM: salmon undifferentiated, SCH: chum salmon, SCK: Chinook salmon, SCO: coho salmon, SPI: pink salmon, SSE: Sockeye salmon, PAR: parr, JUV: juvenile, SMT: smolt.
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Figure 5.2-2. Juvenile salmon catch by life stage at the Susitna River at Curry Station rotary screw trap (PRM 124), 2013. Species and lifestage codes SAM: salmon undifferentiated, SCH: chum salmon, SCK: Chinook salmon, SCO: coho salmon, SPI: pink salmon, SSE: Sockeye salmon, PAR: parr, JUV: juvenile, SMT: smolt.
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Figure 5.2-3. Juvenile salmon catch by life stage at the Susitna River at Talkeetna Station rotary screw trap (PRM 106.9), 2013. Species and lifestage codes SAM: salmon undifferentiated, SCH: chum salmon, SCK: Chinook salmon, SCO: coho salmon, SPI: pink salmon, SSE: Sockeye salmon, PAR: parr, JUV: juvenile, SMT: smolt.
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Figure 5.2-4. Juvenile salmon catch by life stage at the Montana Creek rotary screw trap (PRM 80.8), 2013. Species and lifestage codes SAM: salmon undifferentiated, SCH: chum salmon, SCK: Chinook salmon, SCO: coho salmon, SPI: pink salmon, SSE: Sockeye salmon, PAR: parr, JUV: juvenile, SMT: smolt.
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Figure 5.2-5. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by life stage at the Indian River rotary screw trap (PRM 142.1), 2013.
Figure 5.2-6. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by life stage at the Susitna
River at Curry Station rotary screw trap (PRM 124), 2013.
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Figure 5.2-7. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by life stage at the Susitna River at Talkeetna Station rotary screw trap (PRM 106.9), 2013.
Figure 5.2-8. Timing of juvenile salmon catch (10th to 90th percentile cumulative frequency) by life stage at the Montana
Creek rotary screw trap (PRM 80.8), 2013.
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Figure 5.3-1. Length frequency of juvenile salmon in the Middle and Lower Susitna River during Early Life History sampling (April 29-June 29), 2013
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Figure 5.5-1. Regression of juvenile chinook salmon SGRs over the tag implant date (top) and fish implant length
(bottom) in the Middle and Lower Susitna River; 2013.
y = -0.0065x + 269.82
R² = 0.8369
0%
10%
20%
30%
40%
50%
60%
7/6 7/13 7/20 7/27 8/3 8/10 8/17 8/24 8/31 9/7 9/14% Length/Day Tagging Date
Juvenile Chinook Salmon
y = -0.0163x + 0.3757
R² = 0.1478
0%
10%
20%
30%
40%
50%
60%
69 78 82 84 89 90 91 104 108 111 116 125 131% Length/Day Fish Length (mm)
Juvenile Chinook Salmon
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Figure 5.5-2. Boxplots of specific growth rates for 13 juvenile Chinook salmon plotted by habitat type for the Middle and Lower River, 2013. Note: Box widths are proportional to the sample size for each habitat type. MC = Main Channel; SSB = Side Slough Beaver Complex; USB = Upland Slough Beaver Complex, Trib = single channel tributary, and TM =
Tributary Mouth.
Figure 5.5-3. Boxplots of condition factors for juvenile Chinook salmon plotted by location for the Middle / Lower River,
2013. Note: Box widths are proportional to the sample size for each location.
MC SSB USB Trib TM0.00.10.20.30.40.5SGR (%length/day)MC SMC SC SS SSB US USB BW Trib Trib MouthCWP0.51.01.52.0Condition FactorChinook Salmon
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Figure 5.5-4. Boxplots of condition factors for Arctic grayling plotted by habitat type for the Middle / Lower River, 2013.
Note: Box widths are proportional to the sample size for each habitat type.
MC SMC SC SS SSB US BW Trib Trib Mouth CWP0.51.01.5Arctic Grayling
Condition Factor
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APPENDIX A: SAMPLING SITE MAPS
[See separate file for Appendix.]
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APPENDIX B: DISTRIBUTION OF FISH RADIO-TAGGED IN THE
MIDDLE AND LOWER SUSITNA RIVER, 2013
[See separate file for Appendix.]
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APPENDIX C: WINTER SAMPLING REPORT
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APPENDIX D: FISH SEASONAL DISTIRIBUTION TABLES
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APPENDIX E: RELATIVE ABUNDANCE TABLES
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APPENDIX F: HABITAT ASSOCIATION TABLES
[See separate file for Appendix.]