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Home My WebLink AboutBlack Bear Creek Environmental Monitoring 1984BLA 029 c. 2 Alaska Energy Authority LIBRARY COPY ENVIRONAID ENVIRONMENTAL MONITORING UPPER BLACK BEAR CREEK -1984 - Revised May 1, 1985 OUPLICATF ENVIRON~D 12175 MENDENHALL LOOP ROAD, JUNEAU, ALASKA 99801 · (907l 789 ·9305 ENVIRONMENTAL MONITORING UPPER BLACK BEAR CREEK -198 4 - Revised May 1, 1985 -ACKNOWLEDGEMENTS - Environmental work on Black Bear Creek was funded by the Alaska Power Authority through Harza Engineering Company and received essential support and criticism from other State and Federal agencies: the Alaska Department of Fish and Game, the University of Alaska, the U.S. Fish and Wildlife Service, the U.S. Forest Service, and the National Marine Fisheries Service. In partic- ular, we thank A.D.F.&G. 's staff at the Klawock Hatchery for their physical and moral support, and A.D.F.&G. 's office in Ketchikan for their advice and counsel. Finally, we have enjoyed working with staff of Harza Engineering Company and with Brent Petrie of Alaska Power Authority. Their consistent interest and support greatly enhanced the project. TABLE OF CONTENTS INTRODUCTION . . . . . . . . . . . . . . . I. HYDROLOGIC OBSERVATIONS -1984 Introduction . 1 2 2 Climate During 1984 2 Evaluation of Flow Information for Upper Black Bear Creek 4 Response of Black Lake to Black Bear Lake Outflows 9 Water Temperature Reocrds, Black Bear Creek-1984 10 Lake Temperature and Dissolved Oxygen Profiles 13 Snow Avalanche Hazard at Powerhouse Site . . . 21 II. FISHERIES INVESTIGATIONS Introduction Methods Discussion -Adult Escapement 1984 Discussion -Juvenile Salmonid Rearing Population Summary ........... · . · · · · · · III. WILDLIFE OBSERVATIONS Introduction Methods Specific Observations Mammal Observations 10/29 -11/2; 1984 Mammal Sightings . . . . . . . . . CITATIONS 22 22 23 26 28 32 43 43 43 44 49 51 52 TABLE 1: TABLES, MAPS AND FIGURES Climatic summary information for Ketchikan January through October, 1984 .... 2: Projection of streamflow yields in respective parts 2 of upper Black Bear Creek drainage. Black Bear Lake outlet flows -from Upper Black Bear Creek drainage. • 8 3: Number of spawning sockeye salmon (Oncorhynchus nerka) in the stream system above Black Lake, 1984 33 4: Number of spawning chum salmon (Oncorhynchus keta) in the stream system above Black Lake in 1984 34 5: Number of spawning coho salmon (Oncorhynchus kisutch) in the stream system above Black Lake, 1984 35 6: Population estimates of juvenile rearing salmonids in Black Lake and the stream system above the lake in 1984.36 7: Comparative table of resident rearing juvenile sal- monids in Black Lake and stream system above the lake in 1981 . . . . . . 37 8: Summary of the densities of 0+ and 1+ juvenile coho and juvenile dolly varden in various sections of the stream system above Black Lake . . . . . . . . 38 9: Summary of regression statistics and Fulton's con- dition factor (K) for 1+ coho in a number of areas of the stream in and above Black Lake. August/September, 1984 . . . . . . . . . . . . . . 38 10: Population estimates and densities of fish below, within, and above beaver ponds in Trap Bay, Kadashan and Blind Slough sampling areas, southeastern Alaska, 1982 . . . . . . . . . . . . . . . . . . . . 39 11. Density estimates of juvenile salmonids in southeast Alaska. . . . . . . . . . . . . . . . . . . 40 12. Approximate total numbers of rearing juvenile coho for sections of the stream above Black Lake. . . . 41 13. Chemical data for Black Lake at spring overturns, 1983 and 1984 . . . . . . . . . . . . . . . . . . 41 14. Zooplankton abundance and average size in Black Lake summer, 1982; spring, 1983 and spring, 1984. Counts from the average of two hauls. . . . . . . . . . . . 42 MAP 1: 2: Black Bear Lake Hydroelectric Project. Drainage Areas . Project area showing points of measurement, sampling, and trapping . . . . . . . . , . , FIGURE 1: Rainfall and lake water conditions at Black Lake, Black Bear Creek . . . . . . . . • . . . . . . 2: Relation Spring Fork flows to source flows from Black Bear Lake. Data are for Spring, Summer and Fall measurements . . . . . . . . . 3: Regression relations between outflow, Black Bear Lake and flows at two stations in lower drainage 4: Average daily temperatures for three sites at and immediately below Black Bear Lake, March through October, 1984 . . . . . . . ..... 5: Average daily temperatures for three sites below Powerhouse Site, Black Bear Creek, March through October, 1984 . . . . . . . . . . ..... 6: Profiles of Spring, Summer, Fall and Winter temp- eratures in Black Bear Lake. 1984 values emphasized 7: Profiles of Spring, Summer, Fall and Winter temp- eratures in Black Lake. 1984 values emphasized 8: Profiles of Summer, Fall and Winter dissolved oxygen 4a lOa 3 5 7 11 11 17 18 levels in Black Bear Lake. 1984 values are emphasized 19 9: Profiles of Spring, Summer, Fall and Winter dissolved oxygen levels in Black Lake. 1984 values emphasized . 20 PROJECT INVESTIGATORS This work was completed under the direction of Project Leader, Daniel M. Bishop. Section I, prepared by Mr. Bishop, summarizes and analyzes 1984 hydrologic data in the context of the five years of Environaid measurements. Field work was completed by Mr. Leigh A. Smith, Mr. Bishop, and Dr. Alexander M. Milner. Section II, presenting and analyzing the results of fisheries investigations, was prepared by Dr. Milner. Field work was done by Dr. Milner and Mr. Smith. Section III concerns recent wildlife observations and was pre- pared by Mr. Smith from his field work. - 1 - ENVIRONMENTAL MONITORING, UPPER BLACK BEAR CREEK -1984 - INTRODUCTION This report conforms with the eight point set of objectives put forth in Environaid's contract with Harza Engineering Company, dated April 5, 1984. Additionally, data from earlier Black Bear Creek environmental work by Environaid has been incorporated into analyses to strengthen this year's work and to provide an histor- ical (five year) perspective. A supplement to this report will be provided after the February, 1985 visit to Black Bear Creek. This supplement will include additional lake profiles, stream temperature and flow data, and further notes on wildlife observations. - 2 - I. ,HYDROLOGIC OBSERVATIONS -1984 Introduction This work includes pertinent climatic observations, observations of Black Lake levels, periodic measurements of streamflow, continuous stream temperatures, and periodic profiles of temperature and oxygen in Black and Black Bear Lakes. Where appropriate, data from earlier work were also incorporated into hydrologic analyses, providing a more comprehensive, historical coverage. Climate During 1984 Ketchikan monthly climatic information is provided here as background for other components of this report: Month January February March April May June July August September October TABLE 1: Precipitation Total Departure Average inches from average OF 19.83 +6.10 38.7 15.56 +1. 99 38.9 13.66 +1. 91 42.5 6.43 -5.93 43.0 9.99 +0.37 47.4 14.32 +6.52 52.5 8.30 +0.49 56.0 11.28 -0.81 57.2 9.72 -4.14 52.4 14.98 -10.05 45.0 Climatic summary information for Ketchikan, January through October, 1984 Tern erature Departure from average +5.8 +1.9 +4.3 -0.2 -1.7 -1.6 -2.2 -1.1 -1.7 -1.6 January, February and March were warm, wet months; April, dry; May, cool; June, wet and cool; August, cool; September, relatively dry and cool; and October, dryer than normal. - 3 - Measurements of daily rainfall and Black Lake water level were made during the period of field work, 8/18/84 through 9/10/84, and are graphed in Fig- ure 1. On 25 August 2.00 inches of rainfall measured at Black Lake pro- duced a rise in Black Lake level from 3.49 ft. to 6.17 ft. On 26 August an additional 1.55 inches of rain was measured, while the lake level drop- ped to 5.65 feet. It should also be noted that the Ketchikan weather sta- tion measured only 1.45 inches of rain on 25 August and .25 inches of rain on 26 August. 6 5 4 ~ ·~ +J ~ <li <li <li ~ 4-1 ~ ~ .,...; ~ <li Q) +J ~ <1:1 <1:1 ;3 ...... 4-1 ~ 4-1 u <1:1 <1:1 +J ~ CJl ~ 3- 2 2 Tr 1 0 8/'15/84 Trace 8/31/84 Date during period of fieldwork FIGURE 1: Rainfall and lake water level conditions at Black Lake, Black Bear Creek. - 4 - Evaluation of Flow Information for Upper Black Bear Creek The comparisons presented in this section utilize most of the instantan- eous flow measurements taken over the past five years in upper Black Bear Creek to establish empirical relations between the gaged outlet of Black Bear Lake and other sub-drainage units. The results may be useful in fur- ther examinations of the regulated versus un-regulated outflows of Black Bear Lake and the relation of the regulated regime to downstream flow con- ditions. Results also provide data with which to review the projected yields given by CH 2M Hill in 1981 for sub-drainages below Black Bear Lake. 1. Relation of Spring Fork to Black Bear Lake Outflow: Special attention was given during late summer-fall 1984 to improving knowledge of Spring Fork flows. Nine instantaneous flow measurements now serve to define the relation of Spring Fork flows to the outflow from Black Bear Lake. These values are plotted against comparable gaged out- flows from Black Bear Lake in Figure 2. Figure 2 corroborates earlier descriptions of Spring Forks flows (see Bishop et al, 1982, p.l3), and improves the definition of its relation with discharges from Black Bear Lake for measurements made during Spring thru Fall visits. The observed maximum yield of aquifer(s) feeding the Spring Fork from Black Bear Creek upstream, appears to be between 25 and 30 c.f.s. -pro- bably near to the former value. These maximums develop at outflows from Black Bear Lake which are greater than 60 c.f.s. Between flows of 60 and 8 c.f.s. the percent of aquifer yield reaching Spring Fork increases for about 42% to 75%. The pattern of aquifer yield at flows less than 6 c.f.s. remains un- defined by measurements. Extreme low flows in the Spring Fork remain poorly defined by either winter or summer measurements. U.S.G.S. records show that Black Bear Lake outflow drops to 1 c.f.s. during some winters and also (evidently less frequently) during some summers. But the amount or the duration of the Spring Fork groundwater aquifer's boost to Black Bear Creek's extreme low flows above Black Lake is not yet fully defined. SV3l:JV 3DVNIVHO V>IS\nV l:J3f0l:ld 31lH33130l:IOAH 3>1\fl l:l\f3B >13V1B I 311W l :1 dVW Hll:ION • I 0 31V:JS z !W9~'ll = (1/\ I VW3l:I1S ::10 HlnOW z !W6E" L =(/\I 131.lnO 3>1V1 >I:JVlB z!WOC"9=(/\1).131NI 3>1V1 >I~VlB z !WlB"l =(I) .131.lnO 3>1V1 l:IV3B >I~Vl B SV3l:IV 39VNIVHO 31\l.lVlnWn:> :~. : ... I I I <l~ I ) II ~~. " ~~ .--; ~ "'""' ctl "0 (/) :l"O 0-M (I) ctl c c ctl 0 ~ :... c •l"'i ctl :> ~ c (/)~ C'-' -M "0 (I) :... ::l (/) ctl (I) X: 25 20 15 10 - 5 I I I I I I I G I - 5 - I ;~ I 04---------T--------,---------r--------~------~- 20 40 60 80 c.f.s. Gaged daily flow at outlet of Black Bear Lake (from U.S.G.S. data) 100 FIGURE 2: Relation of Spring Fork flows to source-flows from Black Bear Lake. Data are for Spring, Summer and Fall measurements - 6 - 2. Relation of South Fork to Black Bear Lake outflow: Working with 27 sets of data for Black Bear Lake outlet flows (U.S.G.S. daily averages) versus flows at South Fork mouth (instantaneous flows measured on same days as matched Black Bear Lake outflows) provided the regression: South Fork flow corr. coefficient See Figure 3. .74156 (Black Bear Lake outflow) + 4.3186 = 0.8673 3. Relation of Black Lake outflow to Black Bear Lake outflow: The twenty set comparison of Balck Bear Lake outlet flows (U.S.G.S. daily averages) versus Black Lake outlet flows (instantaneous measure- ents) provided the regression: Black Lake. outflow = 2.4575 (Black Bear Lake outflow) + 15.35 corr. coefficient = 0.9373 See Figure 3. 4. Relation of South Fork flow at mouth to Lake-Branch flow about one mile below Black Bear Lake: This relation was developed for the October, 1983 report (Bishop, et al.) and provided the regression: South Fork flow 0.69 (Lake-Branch flow) -0.47 corr. coefficient 0.824 5. Analysis of comparative yields: Using the afore-given regression relations with respective drainage areas, the projected C.F.S.M. yields were developed for sub-drainage units. These values were then compared with yields from Black Bear Lake. Results are summarized in Table 2. OJ ~ co .....l ,.... co OJ ~ ~ u co --M ~ :3 0 ...., OJ ..c CJl c:: 0 .,., .l,.j co .l,.j CJl 320 280 ' 240 200 160 ~ 120 o.-.. OJ co c:: .l,.j co co .l,j"' c:: co-o .l,.j .,., CJl co .~ § 80 ,.... "0 .,., OJ > ,.... c:: :::11"-l CJl .,_, co OJ :z 40 - 7 - Black Lk. outflow/B.B.Lk. outflow = So.Fk. flow/B.Bear Lk. outflow 20 40 60 c.f. s. 80 100 Gaged daily flows at outlet Black Bear Lake (U.S.G.S. data) FIGURE 3: Regression relations between outflow, Black Bear Lake and flows at two stations in lower drainage. • 120 - 8 - Percent of Percent of Percent of Unit Sub-drainage Drainage Averagedl/ Bl.Bear Lk Bl. Bear Lk Bl. Bear Lk Area C.F.S.M.-C.F.S.M. @ C.S.M. @ C.S.M. @ mi2 c. f. s. /miL Ave. flow Low f 1 ow_:_! High flow:-'./ 1. Black Bear Lake 1.82 15.3 100 100 100 2. ca. 1 mi. below BBLk 3.10 ll.5 75.2 144.6 67.2 3. sub-unit below BBLk 1. 28 6.09 39.8 208.0 20.6 4. South Fk. at mouth 2.17 ll.5 75.2 134.6 65.8 5. sub-unit surrounding 2.12 10.8 70.5 125.2 58.5 and immed. above BBLk 6. Black Lk. at outlet 7.39 11.3 73.9 136.1 64.3 TABLE 2: Projection of streamflow yields in respective parts of upper Black Bear Creek drainage. Black Bear Lake outlet flows-from U.S.G.S. data. Related flows for other sub-drainage units based upon spring- summer-fall measurements. l/ Averaged C.F.S.M. for outlet Bl. Bear Lk. taken from U.S.G.S. data; (1981 = 18.4; 1982 13.0; 1983 = 14.4); other values derived using regressions. ll Values derived using regression relationships. Low flow of 5 c.f.s. assumed for outlet, Black Bear Lake. 11 Values derived using regression relationships. High flow of 100 c.f.s. assumed for outlet, Black Bear Lake. The CH 2M-Hill hydrology report (1981) estimated average annual runoff from Black Bear Lake of 14.3 C.F.S.M., and from Black Lake of about 10.5 C.F.S.M. This compares with three years (1981,82,83) of U.S.G.S. meas- ured flows which average 15.3 C.F.S.M. and with regression-derived sug- gested yield for Black Lake outlet of 11.3 C.F.S.M. 6. Conclusions from streamflow analyses: A fairly good basis for evaluating flows of the Spring Fork is now available. This may be of use in design and evaluation of power- house outflows. Estimates of relative contributions of respective sub-drainage units above the mouth of Black Lake can be used to refine predictions of - 9 - effects of flow regulation. The measure-based C.F.S.M. yields (1981-8~) for sub-drainages are about 1 C.F.S.M. greater than the values projected in 1981 by CH 2M-Hill. The percentage reduction of yield with basin elevation is slightly less than anticipated by CH2M-Hill hydrologists. The high flow to low flow character of regression relations for re- spective sub-drainage units (as demonstrated in Table 2) has some interesting, if tentative, implications: a. There is indication that the sub-drainage immediately below Black Bear Lake and the South Fork drainage support relatively larger base flows than the outlet flow from Black Bear Lake, and conversely yield lower peak flows. In both cases this tentative conclusion is supported by presence of sizeable ground water storage features, notably extensive talus slopes and landslide deposits. b. The regression-derived implications described in (a) above are less prominent below Black Lake, suggesting sub-drainages below the South Fork may contain less storage to support low flows. Response of Black Lake Level to Black Bear Lake Outflows High flood levels of Black Lake on August 25, 1984, prompted an exam- ination of the relation between Black Bear Lake outflows and Black Bear Lake levels observed during field work in 1981, 1982,1983, and 1984. A summary of regression relations is given below: 1981 Black Lk.level .02541 Black Bear Lk. outflow+ 2.17 corr.coef .975 1982 " " " .0206 " " " " + 2.72 " " .754 1983 " " " .0262 " " " " + 2.67 " " .916 1984 " " " = .0211 " " " " + 2.43 " " .960 Further evaluation of these developed relations indicates that Black Lake has not shifted upward relative to Black Bear Lake outflow for the 1984 set of observations. The record high flood level of August 25, 1984 -10 - was evidently the result of especially high outflows from Black Bear Lake. On August 25, average outflow from Black Bear Lake was 109 c.f.s.; on August 26, 167 c.f.s. The average discharge of 167 c.f.s. is the highest during any period when Black Lake level-was observed. Although there is a potential for alteration in the streamflow and lake level control at the outlet of Black Lake, such change is not demon- strated in this examination. Water Temperature Records, Black Bear Creek -1984 Six ENDECO 109 thermographs were re-installed in the Black Bear Creek system in late March, 1984. Five stations, previously instrumented above Black Lake, were again selected for this instrumentation. A sixth station was installed 20 feet below the lake surface at the north end of Black Bear Lake. Records were recovered for processing at the end of October, and graphed data are shown in Figures 4 and 5. The powerhouse site thermograph record (PHS Figure 4) extends only to June 23. The film cartridge failed. Corrections were made to the records for the underwater thermograph (UWS) and the Powerhouse site instrument (PHS). Both of these units had separated mercury columns. Each record was corrected with a single adjustment figure based upon other temperature measurements, either de- rived from Black Bear Lake profiles, (for UWS thermograph) or from mis- cellaneous stream temperatures made during some flow measurements of the Spring Fork (for SFS thermograph). The temperature values from April through October, 1984 are depressed relative to earlier years of observation. This is consistent with cli- matic records for Ketchikan (see Table 1). Black Bear Lake outlet's daily average did not reach l°C until May 12, and average outlet temp- eratures exceeded l2°C for only five days. Temperatures at -20 ft. depth (UWS) appear responsive to lake surface conditions. The probable date of ice departure from Black Bear Lake is base camp out-migrat1on traps MAP 2: Project area showing points of measurement, sampling and trapping. lake profile point BLACK BEAR PROJECT 1/2 LAKE AREA 0 I approx. I scale KEY I.AAP 1mi. I ) {.~.'I It I II I • I •I •••. ~~ 1_~:~4.-'.,..l....L...LI I I I I I • ol .~:~~liJ.-LLl.I.J. I J fj_J_j__L_Lf lLI.~ LLI ~~ ,\'~f I ~.1.1 f >-l_f II J) JJ I_~ I Jt.~ . .l tJ.4J.~ l .• ~~<r> I <,wu...<.A.LLU.J..L.LL<.W-...>-.LLLU_._,~'"".___._._,_~~~~~~'-W~~0~'~l~.L~~_LL~~~~~~~~\(._.jql_.»_ ... -:-r ; .. --~-::: 1 -··~~~~~ ·:~~ l·::~~ 6""rl {l"tl '1JJ/tt/H ---~-----~------------ _:::.~_:;:~~.!~=;;:~.~~~::_ ~lWfl '1'0JlWJWIJ<tll USlJO:l 4Jn.ua• Hl ,lllf'l ltllJ"] 'll•o.t '8\ll.Jds uo •r•• •1uaum•r.-... <tJ•n"" 1ad.,1 •""''H'l', -t:t)IIJ• pu• •ante!\ PllllJitl.JO;;.-UI'I Uil'll11lll<l Wil;m<JJ:>JtH' un p01w•q •uotPIUJC.'l :J.~J-{-1!1f"' P<tHinfre !lliM'olf!'A S:fS IIV /i If (SAS) "lfS 'I)Jt".! Wupds (1111) a'l"l Jl:l"'HJ 1:tddo "UOf)P.U~d.~9 uaq!hl J!.J.n::t.&a• Ql ;w.p JOJJ"] '!l<llnfP'\ <!IJfiJftJ>Jrl•<JI liJljtiJI~ -41!1•1 pue •*'l""' pit).HUJO.J-\Jf'l U:flt,llh.j ;,.}ll.>l"'jjf(' UU P"'n'q •uutvao.JJo::t :'.9'(~ qt,., p~l•nlpe ,.,ntl! ... srom uv /l "tJ!bf ~<f) ·~d ···. --·· "tQf>l 'JitqO:)l::IQ 4tl'l'IOJ1f) 4;J.JIIH •"'.:titJJ Jl';,.l Jt.nliJ '"lfS ••no4JOJ*Id' AO(OJq ""'ll" n.up JCJ UJnl•nd•;;,l AJlwp OJIW.J<tiiV l{ ]lfl:JU '1961 • .nqcuo 48noJ.'Il 4:U:IfW •.,"'., uaw '1-'"'111 ""1"'(1 A{*:t•Jpao-l pue 1• &ilolf• U'.Hfl lOS •unlv.J#"dw~l At J•P a8&Johy Tr :Uto:)IJ Ol 1l 01 I! " "' . . -12 - signaled May 22-23 by a marked temperature drop of UWS, indicating lake mixing. An inverse relation of dropping lake surface temperatures (BBL) with rising temperatures at -20 depth (UWS) is seen at several periods. This relation suggests varied intensities of wind-mixing. The record for the powerhouse site (PHS) shows the same marked fluc- tuations as found in the 1982-83 record and amplitudes are similar. PHS values during late March-April 1984, when averaged, indicate sim- ilar temperatures to those of the Spring Fork origin (SFS) some 2,000 feet downstream. In May, 1984, averages of PHS became higher than comparable SFS values. Spring Fork temperatures (SFS) in April and May 1984 were about a half lower than temperatures measured downstream by the buried Stream Gravel thermograph (SGS). This difference disappeared in June, 1984, but SGS temperatures did not reach quite as high summer peaks as SFS values. This pattern, similar to that demonstrated in the 1982-83 thermograph records, indicates that the waters emerging into the stream- bed at the SGS site are from deeper and/or slowermoving flow paths than water emerging at SFS. These temperature data were received after completion of all other parts of this report. It is of interest to note, however, that while spring- summer 1984 temperatures in Upper Black Bear Creek were about one to two degrees lower than the comparable period in spring -summer, 1981, coho l+ juveniles in 1984 showed a somewhat better condition than those of 1981 (see Tables 7 and 9). -13 - Lake Temperature and Dissolved Oxygen Profiles All profiles made to date on Black Bear and Black Lakes have been util- ized to produce the graphs shown as Figures 6,7,8, and 9. These graphs establish ·the observed ranges of values for respective seasons. The profiles of 1984 are super-imposed on these Figures. 1. Temperature profile observations are shown graphically in Figures 6 and 7 and are summarized below: Winter temperatures range from near 0°C at lake surface (or below ice) to near 4°C below the thermocline during winters with early ice cover. During winters with extensive open water, thermocline is less well defined and temperatures at greater depth are nearer to 2°C. Thermocline in Black Bear Lake under ice is about 10 -15 ft. below the surface, and without ice is poorly defined. Thermocline in Black Lake under ice is about 5 ft. below the surface, and, again, during open winters is poorly defined. Spring profiles in Black Bear Lake are not_well represented with data. Spring comes to Black Bear Lake in the months of May and June, and commonly follows break-up of lake ice. A strongly warmed surface layer 10 -20 ft. thick is likely over water of about 4°C. Spring temperature conditions in Black Lake are likely to begin at about 4°C uniform temperature ane elevate rapidly to 10 -l2°C at the surface and 6 -7°C near the lake bottom. Summer surface temperatures in Black Bear Lake range from l5°C in early August to 8°C in early September. Summer thermoclines in Black Bear Lake range between depths of 20 and 30 feet. Temperatures below the thermocline range from about 5 to 8 °C. Summer surface temperatures in Black Lake range from l6°C in August to ll°C in early September. Reduction in temperature with depth is not well defined as a thermocline in this shallow lake, and thermal -14 - mixing is evident to the bottom. Fall temperatures in Black Bear Lake are nearly constant with depth and range from 7 !/2 to 5°C. Extensive mixing reaches to 100ft. A similar condition occurs in Black Lake between about 10° and 6°C, with near-surface waters elevated 1 -2°C. 1984 Observations are hi-lighted in Figures 4 and 5. The March, 1984 profiles for both lakes fall almost entirely within the range of profiles observed during winter seasons. The late summer (9/6/84) profile for Black Bear Lake falls in the middle to low part of the summer range of observations. Similarly, the 8/19/84 profile for Black Lake is c at the bottom of the summer temperature band. Profiles of Black Bear and Black Lakes, measured on 10/30 and 10/29/84 respectively, are both at the base of fall observations made for this project. 2. Dissolved oxygen profile observations are shown graphically in ures 8 and 9, and are summarized below: Winter dissolved oxygen levels in Black Bear Lake are between 11 and 14 p.p.m. for the first 30 feet under the lake or lake ice surface. A depression to 8 p.p.m. has been observed at greater depths on one water sampling. Winter dissolved oxygen levels in Black Lake are between 12 and 14 p.p.m. for the first 10 ft. below the lake or lake-ice surface. Un- like Black Bear Lake, depressed oxygen levels as low as 4 p.p.m. de- velop under ice cover, at 30 ft. below the surface of Black Lake. Spring dissolved oxygen profiles for Black Bear Lake are represented only by measurements on 5/31/83, the ice-free spr following a -15 - winter of very little ice cover and by the 3/29/84 profile. Both . profiles show dissolved oxygen )12 p.p.m. for levels above 100ft. Black Lake spring dissolved oxygen profiles indicate marked depres- sion below 30 ft. to 2 p.p/m. Again, this occurred under ice-cover. Above 30ft., levels range from 10.5 to 13 p.p.m. dissolved oxygen. Summer dissolved oxygen levels in Black Bear Lake range from 10 to 11 p.p.m. for the first 30 -35 feet below the surface. Temperature inversions between 35 and 50 ft. depths produce rapid elevation of 1 - 2 p.p;m. dissolved oxygen levels. The elevated dissolved oxygen strata commonly ranges from 10 -20 ft. thick and is followed by depressions of oxygen level of 1 to 9 p.p.m. Summer dissolved oxygen levels in Black Lake range between 8.5 and 11 p.p.m. for the first 20 ft. of depth. Below 20 ft. summer oxygen levels drop to 4 - 7 p.p.m. near the lake bottom. Fall dissolved oxygen level in Black Bear Lake is most likely to be rathe_r constant with depth ranging between 10 and 13 p.p/m. Early fall profiles may show moderate depression at greater depth. A similar uniformity exists for Black Lake, where Fall oxygen levels commonly range from 10-12 p.p.m., and have not been observed lower than 9 p.p.m. 1984 oxygen levels are hi-lighted in Figures 8 and 9. The 3/29/84 profile for Black Bear Lake was taken through ice cover, and is es- sentially a winter profile. The 3/26/84 profile for Black Lake was taken in open lake conditions and shows uniformly high oxygen levels at or near 13 p.p.m. The summer profile for Black Bear Lake (9/6/84) shows generally high oxygen levels for the summer season, in response to the rela- tively cold temperature conditions. Similarly, Black Lake oxygen -16 - levels for 8/19/84 are consistently high for summer profiles in response to the consistently low temperature profile for that date. 14 12- u 10 0 Q) ~ ::l ~ t1l ~ Q) 3 0. m E-o ·~ Q) ~ t1l :::r: 6 4 2 .o 20 FIGURE 6: 40 -17 - 9/6/84 60 Depth. Feet 3/29/84 80 SprinB Stmnner Fall Winter 10/30/84 ··------..--""'!"' 100 Profi.les of Spring, Summer, Fall and Winter temperatures in Black Bear Lake. 1984 values emphasized u • <I) ~ ~ ~ 8 QJ 0 ~ E-o 1-4 <I) ~ ~ 4 -18 - 8/19/84 10/29/84 3/26/84 0~---------r---------.----------~---------~--------~ ·------, 10 20 30 Depth. Feet 40 so FIGYRE 1: Profiles of Sprin~. Summer, Fall and Winter temperatures in Black Lake. 1984 values are emphasized e . 0.. . 0.. I ~ C1) ()() :>, >< 0 '1:l C1) > ~ 0 Cll Cll ...-1 Q 14 12 10 8 6- 4 2- 20 40 -19- ~~ = Summer ~· = Fall ~ = Winter 60 Depth, Feet 80 100 10/30/84 9/6/84 . FIGURE 8: Profiles of Summer, Fall and Winter dissolved oxygen ·levels in Black Bear Lake. 1984 values are emphasized 14 12 10 8 . Q. . Q. 8 !=: Qj 00 >. >< 0 ~ Qj > 6 ~ 0 Cll Cll ~ ~ 4 0 ' -20 - ~ = Spring • = Summer ~ = Fall = Hinter 3/26/84 10/29/84 8/19/84 10 20 30 40 50 Depth. Feet . FIGURE 9: Profiles of Sprin~. Summer. Fall and Winter dissolved · oxygen levels. in Black Lake. 198.4 v.alues are emphasized. -21 - Snow Aval-nche Hazard at Powerhouse Site: On 10/31/84 we walked to the powerhouse site to service a thermograph installed in the stream at that point. We travelled up the stream chan- nel to reach the site. About a half mile below the powerhouse site we encountered a tongue of snow 2 - 3 ft. thick over the stream channel. The adjoining stream margins had about 6 -10 inches of snow. This snow tongue had a rough texture like an avalanche surface. A few hundred yards below the power- house site most evidence of the tongue had been eliminated by the stream flow, which was even then advancing into the snow deposit over the chan- nel. At the powerhouse there were scattered evidences of the snow de- posit along the edge of the stream channel. The manner in which this snow tongue was deposited into the stream chan- nel is unclear. One possibility is that a dry snow avalanche swept down the face of the falls to the reach above the powerhouse, to then be re- deposited by the stream itself. The observation of this deposit prompted re-examination of the channel and its margins above the powerhouse site. There is a 20 ft. tall spruce snag (with a snapped top) in mid-channel about 200 -300 ft. above the powerhouse site. This wind-damaged tree suggests that a dry-snow aval- anche may have occurred here some years ago. The brush margins adjacent to the stream channel above the powerhouse site also suggest the possi- bility of avalanche conditions. It may be prudent to examine this possibility, and to consider the loc- ation of the powerhouse facility so that it would not be directly below the possible snow avalanche route as suggested by local conditions. The facility might be safer if tucked in behind the end of the spur ridge which meets the right side of the channel (viewed downstream) above the powerhous~ site. This does not appear to involve a large change in design. -22 - II. FISHERIES INVESTIGATIONS Introduction This work encompasses a further season of adult escapement counts in the stream system above Black Lake and population estimates of rearing juvenile salmonids in this system, including the associated beaver ponds and Black Lake itself. Escapement counts and juvenile population estimates were made in the summer/fall of 1981 (Bishop, et al 1982 a). Further escapement counts were made in 1982 (Bishop, et al 1982b). Additionally in the spring of 1982 and 1983 extensive fyke net programs were undertaken to ascertain timing and numbers of coho (Oncorhynchus kisutch), chum (0 keta), pink (0 gorbuscha), and sockeye (0 nerka) fry together with coho and sockeye smolt from Black Lake and the system above. This data was evaluated with reference to 1981 escapement counts and the pre and post-project temperature and flow regimes (Bishop, et al 1982a, Bishop, et al 1983). A principal aim of this work was to compare and contrast the juvenile pop- ulation estimates of 1981 with these 1984 figures, particularly in view of the beaver activity in the drainage and the increase in beaver pond area. This information may provide a basis for establishing habitat productivity, particularly as related to the proposed hydroelectric project. Estimates were made in the same four stream sections A,B,C,and D as identi- fied in the 1982a report. These sections average 100 m in length. Section A (2,116 m2 ) and B (1,790 m2) are in Zone I which is made up of 915 m of streambed with sustained, slow moving water in a channel that is princi- pally between 15 m and 23 m wide. The gradient is approximately .04% with typical flows of 6 em to 9 em/sec. The streambed is predominately made up of sands and silts with log debris and numerous logs present on the streambed. Numerous indentations occur in the banks and there are a num- ber of side channels which are principally attributable to beaver runs. The banks are frequently overhung by riparian vegetation. Sections C (1,469 m2 ) and D (692 m2 ) are present in Zone II in the lower and upper part of the Spring Fork. Th~ total length of Zone II is 305 m and the channel width is variable. The gradient is between 1 and 2 % and the substrate is predominantly coarse gravel and small cobble. -23 - The three major sets of beaver ponds studied were: 1. Black Lake associated ponds -near stream entrance to Black Lake where the beaver have ponded run-off water that enters the main channel with a series of small dams. Approximate pond area -725 m2. The area is sur- rounded by sedges. 2. Lake Fork beaver ponds - a set of major ponds on the Lake Fork created by two principal dams. Approximate pond area -904m2. A number of fallen logs are present and grasses, sedges and alder are the bordering vegetation. In the long backwater area to the site of these ponds the alder provides significant canopy cover. 3. South Fork beaver ponds -these ponds are a relatively recent addition to the system, being first observed in 1982. Beaver activity has been heavy in the area, erecting a wide and massive dam on the South Fork, approximately 400 m upstream from the junction with the main stream. This has flooded a fairly extensive area resulting in the demise of a number of spruce/hemlock trees. The approximate area of these ponds at the time of sampling was 1,450 m2 . A break in the dam had occurred which had not been repaired and a lower level resulted than previously observed. Black Lake (62 acres and mean depth 7.6 m) was also sampled for juvenile fish and further limnological investigations undertaken. Methods A total of seven surveys for adult salmonids were conducted above Black Lake during the period August 18th to September 9th. Additional surveys, principally for coho, were undertaken between October 29th and November 2nd. The technique employed followed the two man team strategy of Straty (1960). Both members of the team covered a given length of stream either on foot or by canoe making separate counts of the adults observed. The counts were totalled and the averages noted. Records were made for respective sections of the stream so as to identify the principal spawning areas. The results are given in Tables 3, 4, and 5. 24 - Estimates of the rearing juvenile salmonid populations were made using min- now traps and mark and recapture techniques. Other possible methods of capture, for example seine nets and electro-shocking were considered un- suitable due to the large amounts of fallen logs and debris in the stream and the presence of large numbers of adult spawning salmonids. In both stream sections A and B forty traps of 3 mm (1/8 in.) and 6 mm (1/4 in.) mesh were used to trap fish baited with boraxed salmon eggs. In sec- tions C and D twenty-five minnow traps were used. Fish captured were mark- ed with a hole in the caudal fin. Traps were set in the same location the following day and the ratio of marked fish to unmarked fish recorded. Pop- ulation estimates were then made using Chapman's (1951) modification of the Petersen formula. N _ (M + 1) (C + 1) • -( R + 1) where M = number of fish marked C catch or sample taken for census R = number of recaptured marks in the sample N = population present throughout the experiment. Coho were divided into young of the year (0+) and fingerlings (1+) accord- ing to fork length. Sixty mm was used as the dividing length and subseq- uently plotting histograms of lengths of representative fish samples from each section, showed this to be an appropriate division., 95% confidence intervals were made using the Poisson distribution. As the beaver ponds were more discrete bodies of still or slow moving water, multiple mark and recapture techniques were employed over a 4 day period for each set of ponds. Fish were given a caudal punch as before on the first day but on subsequent recaptures unmarked fish were marked and re- leased and the ratios recorded. On the last day the number of marked to unmarked fish in the sample was noted and no marking occurred. Population estimates were made using the formula of Schumacher and Eschmeyer (1943) 1 (Mt Rt) N (Ct Mt2) where Mt = the total marked fish at the start of the t th day - -25 - or other interval i.e. the number previously marked less any accidently killed at previous recaptures the total sample taken on day t the number of marked recaptives in the sample Ct 95% confidence limits of the population estimates were calculated using the method of Schumacher and Eschmeyer (1943). A similar mark and recapture exercise was undertaken in Black Lake over six days using 45 minnow traps including 3 large ones. (The population estimates, 95% confidence intervals, and fish density/m2 are given for each area sampled in Table 6 Comparative estimates for 1981 are given in Table 7 and a summary of fish densities for each area in. Table 8. For each area sampled approximately 200 fish were randomly taken for length analysis and 100 1+ coho were also weighed. Regression analysis of log length against log '.·.eight for the 1+ coho was undertaken for each area and the resultant regression equations and correlation coefficients (r2) are given in Table 9. Fulton's (1911) condition factor (K) was also cal- culated for each sample, (Tables 6 and 9). K = I3 X 105 where w weight in grams 1 fength in nun 105 = factor to bring the value of K near unity (Car lander 1969) Further limnological investigations were undertaken in April on Black Lake with regard to its production and carrying capacity for salmonids. Water samples were taken after the spring overturn at 1/3 and 2/3 lake depthsat the sampling station established in the deepest point of the lake (approx 12m). The samples were analyzed for phosphorus and nitrogen levels (Table 13 ). Zooplankton samples were also taken using a 153 micron mesh net with a 0.5 m circular mouth. Two vertical haul samples were taken and -26 - preserved in 4% formaldehyde. Laboratory work was done by the ADF&G Limnol- ogy Laboratory in Soldotna, Alaska. Results are shown in Table 14, along with earlier data for 1982 and 1983 not previously reported. Discussion Adult Escapement 1984 The peak of the 1984 sockeye run was during the last week in August, similar to the timing of peaks ,in 1981 and 1982. On August 18th the majority of the sockeye were below the forks in non-spawning habitat or still in Black Lake. The stream was extremely low at this time. However, persistent rain from August 20 caused the stream to markedly rise and fish started to move onto the spawning gravels. Pairing and redd digging was evident during the last week in August. By the count on September 9 the run had peaked and virtual- ly all the sockeye were on spawning gravels. Significant numbers of dead or dying fish were observed. The number of female and male sockeye spawners observed at the peak (Table 3) was 571, significantly lower than the 1981 and 1982 figures of 1,190 and 828 respectively. Spawners, as in previous years, were again fairly equally div- ided between the south tributary and the Black Bear Lake system. Extrapol- ating for mortality between counts, it is estimated that in total approxi- mately 375 sockeye spawned in the Black Bear system and 275 in the South Fork. One significant difference between the spawning activity in 1984 compared to 1982 related to the south tributary and the new beaver dam. In 1982, the year the beaver ponds were first observe~, the dam proved to be an im- passable barrier to upstream sockeye migration during low August flows. A small number, some 23 fish, were able to make it above the dam in September, 1982, after heavy fall rains had raised the level of the creek. This year a break was observed in the darn which was not repaired by the beaver, there- by allowing some 120 sockeye to surmount the barriers. Approximately SO% of these fish remained in the beaver pond and presumably spawned in the central section where the gravels were less affected by sediment settled out by the ponds. As in both 1981 and 1982, spawning sockeye did not run above the beaver -27 - dam on the Lake Fork. However, more use was made of the spawning gravels in the Lake Fork below the heaver pond than either 1981 or 1982. Another interesting aspect of the observations this year was the effect of the new dam on the Spring Fork adjacent to the Lake Fork dam. This was under con- struction in late March of 1984 and had subsequently been added to and was virtually complete by August. However, the average height of this dam was 0.6 to 0. 75 meters compared to the South Fork dam of 1.75 meters to 2.00 meters, apart from where the break occurred. The Spring Fork dam did not appear to be a significant barrier to sockeye moving up onto the gravels above it. These gravels are considered some of the highest quality in the sys- tem, particularly in view of the reduced fluctuations in stream level that occur in this section as a result of being predominant spring fed. The numbers of jacks or precocious sockeye males in the run was less than 2%. As in year 1982, virtually no pink salmon migrated through and spawned above Black Lake this year. Two pinks were seen above the lake. The to- tal number of spawning pinks in the whole system was low,concurring with the odd/even trend the stream has displayed over the last eight years. Consequently, no over-spawning of sockeye redds by pink salmon occurred as it dirl in lO.Rl resulting in a very lo'·r socl<·eye egg to fry survival rate. of 0. 7% in the subsequent incubation period. As no escapement counts were made in 1983, it is unclear whether this over-spawning was repeated in the odd year. The maximum number of chum observed above Black Lake in 1984 was 10 with the majority using the upwellings in Spring Fork for spawning (Table 4). This small number is similar to the maximum of 5 in 1981 and 11 in 1982 sub- stantiating the view that the principal area for spawning chum salmon in the system is below Black Lake. The coho counts conducted on October 29 and November 1 (Table 5 ) indic- ated approximately 60 fish and although the stream was relatively low and observer passage up thestream fairly easy, numbers were probably higher. Ice formation, on the beaver ponds made observations in these areas dif- ficult. The November 1 count was clearly under the actual number present. Coho were noted jum.ning in tJ.oe lake and undoubtedly additional coho would -28 - enter the system later this year. The question of the total number of coho spawners is discussed further in the section on juvenile rearing populations. This year, the Prince of Wales Lodge in Klawock had a 14 ft. aluminum skiff available for hire on Black Lake. It was used by lodge guests and residents of the area. Additionally, fishing by boat at the mouth and al~ng the stream for coho was also significant. Will Jones (pers. comm.) suggested that approximately 150 coho had been caught and removed this year. A number of these fishermen were from the nearby logging camp. It is uncertain how many of these fish would have spawned above the lake this year but even the loss of 30 -40 fish would have a significant effect on coho production above Black Lake. Approximately 20 -30 adult dolly varden were observed above Black Lake, the majority in the South Fork beaver pond. Juvenile Salmonid Rearing Population It is evident from a comparison of Tables 6 and 7 that greater numbers of both young of the year (0+) and fingerlings (1+) were found this year in all areas of the stream system sampled than in 1981. In 1981, for ex- ample, juvenile fish in Section D were of such low density that a mark and recapture experiment was not possible. The most notable increases, particularly for young of the year, were in Sections A and B of the stream, and the beaver ponds on the Lake Fork. Estimates of both 0+ and 1+ coho in 1984 for the set of beaver ponds on the south side near the creek en- trance to the lake were very similar to the 1981 figures indicating the fairly stable populations in these ponds, presumably as a function of their only being accessible at relatively high stages of the stream. In 1981 no population estimates were made on sections of the south trib- utary but numbers were probably of a similar level to sections of the Spring Fork. The new beaver pond on the south tributary, even with a lowering of the water level due to a breakage in the dam, constituted a significant area for juvenile rearing and had the highest fish densities (no./m2) with re- gard to both young of the year (0+) and fingerlings (1+) (Table 8 ). This -29 - area has probably contributed significantly to the increased production of rearing juvenile coho this year. Bryant (in press) discusses the role of beaver dams as coho salmon habitat in southeast Alaskan streams. Five beaver pond systems in three drainages were studied, indicating densities of coho generally higher than those re- ported in other systems without ponds. Bryant suggests this is a resul~ of a larger surface area of water with more diversity of habitat in systems with beaver dams. Possible detrimental effects of beaver ponds to juvenile coho are a decrease in oxygen levels and increase in temperature in the ponds and dewatering of the system below the dam. None of these effects are likely to be of significance in the Black Bear Creek system. One notable difference between Bryant's results and those for the Black Bear system is the density of fish in the beaver ponds compared to other areas of the stream. In Bryant's study the numbers of fish/m2 in the ponds was typically less than sections of the stream upstream of the ponds (Table 10) although total production in terms of the number of fish was greater in the ponds. However, in Black Bear Creek the density of 1+ coho was markedly higher in the ponds on both the Lake Fork and south tributary than in other sections of the stream. Stream densities in the more productive Sections A and B were on average less than density estimates of juvenile salmonids in other southeast Alaska streams (Table 8 )although these are typically small~ er streams. In addition to supporting high densities of coho, these ponds may be of sig- nificance in providing refuge when flows are high in the stream and as over- wintering habitat. However, Dolloff (pers. comrn.) in a study of overwinter- ing juvenile populations in a southeast Alaskan drainage with beaver ponds, found no significant movement into the ponds during this time. Along with increased numbers of juvenile coho in the system, considerably higher populations of dolly varden were found than in 1981 although over- all numbers are low. It is interesting to note that the majority of dolly varden were located in the beaver ponds and very few in the sections of stream sampled. One possible reason, particularly with relation to Sections -30 - A and B where the substrate is silt and sand, is that benthic invertebrate productions in these areas is low. Dolly varden, being typically bottom feeders, may favor mud substrate of the beaver ponds where benthic produc- tion, particularly of chironomids, is likely to be significantly higher. Numbers of 1+ coho in Black Lake were almost identical to 1981 but numbers of 0+ coho were somewhat higher. Extensive shallow littoral areas in the lake are restricted as the shoreline is frequently steep, particularly on the north side. Cover in many areas of the lake is enhanced by fallen trees and logs. The littoral rearing habitat is certainly more favorable than a deep, steep sided lake, for example Black Bear Lake. Black Lake may possibly be unable to support considerably greater numbers of juvenile coho due to the limited amount of suitable rearing habitat. Consequently, if the beaver pond habitat is lost and the lake is unable to optionally support additional fish, the overall production of juvenile coho above Black Lake may be reduced. Numbers of rearing dolly varden in the lake are low. Condition factors (K) calculated for the different areas sampled were fair- ly similar and ranged from 1.15 to 1.22. There is little comparative in- formation on condition factor from other southeast streams. Examining again the likely number of coho spawners above Black Lake, a rough extrapolation can be made from the population estimates of the young of the year (0+) juveniles. Table 12 summarizes the approximate total numbers for total areas of the stream. The total for 0+ coho is 46,426 and this figure does not include the south tributary above the beaver dam or Black Lake where have migrated in from the upper system. Allowing for mortality this year, a rough figure would be 50,000 coho fry emerged from the gravel this spring. Using a typical egg to fry survival rate of 10% equates, very approximately, to 500,000 eggs being laid last fall. Taking the typical fecundity rate of coho to be 2,500 to 4,000 eggs trans- lates to 125 to 200 female spawners. Assuming a 1:1 ratio of females to males would hence indicate a total of 250 to 400 coho spawners in 1983 ab- ove Black Lake. It is considered that the actual figure was likely to have been in the region of 150 to 200 and this may indicate a higher than typical -31 - egg to fry survival rate of around 15 to 20%. In 1981 it is estimated that the beaver ponds, in terms of relative num- bers of fish, constituted 15 to 20% of the rearing habitat above Black Lake for 1+ coho. Despite increased numbers of 1+ coho in the stream, particularly Zone I, the addition of the South Fork beaver pond maintained the value for 1984 at an estimated 20%. For 0+ coho, in terms of numbers, the contribution of the beaver ponds is approximately 15%. Black Lake -Zooplankton and Chemical Parameters In both the summer of 1982 and spring of 1984 Black Lake was dominated by low numbers of the cladoceron Bosmina longirostris (Table 14). A few chy- dords were also present and Holopedium was present in August 1981. Daphnia was conspicuously absent. Of the copepods, Cyclops was found in extremely small numbers and Diaptomus was present in the summer. Small numbers of rotifers were also present, particularly Asplanchna. This data supports earlier conclusions (Bishop, et al. 1982) that there is heavy predation by the sockeye on the zooplankton. In addition to numbers of Bosmina longirostris being low, their mean th (0.31 to 0.34mm) is extremely small and these are some of the lowest values recorded for Alaskan lakes (Koenings pers. comm.). The sockeye's preferred prey, the cladoceron Daphnia is like to have been grazed to negligible numbers and thus they are having to utilize the less preferential .......;;. ____ _ resulting in low density and small size. The chemical information showed the nitrogen to phosphorus ratio (N:P) to be 26:1 in the spring of 1983 and 32:1 in the spring of 1984. These values are greater than the 15:1 ratio considered to indicate a nitrogen limit- ation. Values of phosphorus are low, as is typical of many southeastern Alaskan lakes. Phosphorus is the limiting nutrient for primary and hence secondary production in Black Lake. As in previous reports, Black Lake appears to be close to its maximum carrying capacity for juvenile sockeye. -32 - Summary In 1984 the peak of the sockeye run was in late August, as in previous years, althouth numbers were less. 375 sockeye were estimated to have spawned in the Black Bear system and 275 in the south fork. No sockeye spawned above the beaver dam on the Lake Fork of the Black Bear system but more fish moved above the south tributary dam than in 1982. The new dam on the Spring Fork did not restrict upstream migration of spawners. A small number of chum spawned above Black Lake, typically near the up- welling in the Spring Fork. The majority of the chum spawn below Black Lake. Coho counts, in late October/early November located approximately 60 fish above Black Lake. Analyzing the young of the year estimates for 1984 above Black Lake and using a rough extrapolation with estimated fecundity and mortality indicate a figure of 150 to 200 coho spawned in 1983. The placement of a skiff for coho fishing on Black Lake, together with fairly heavy fishing along the creek is likely to reduce this fig- ure in 1984. Juvenile population estimates in and above Black Lake showed signifi- cantly higher numbers of coho than the previous estimates in 1981, parti- cularly young of the year (0+). The major areas of coho rearing above Black Lake are the slow moving section below the forks (Zone I) and the beaver ponds. The beaver pond on the south tributary made a significant contribution to the rearing habitat and overall supported the highest densities of juvenile coho. This condition contrasted with another S.E. Alaska investigation (Bryant, 1983) who found lower density of coho in beaver ponds, though higher total numbers due to large ponded areas. In- creased numbers of juvenile dolly varden were also found in 1984 and were restricted mainly to the beaver ponds. Zooplankton and chemical analyses of Black Lake further support the con- clusion that the nutrient limiting to productivity is phosphorus, and the lake is at its carrying capacity for juvenile coho' -33 - Location Date -1984 8/18 8/21 8/27 8/31-1 9/4 9/7 9/9 Mouth of creek to Wes~ 273 349 2 37 4 2 Fork of south tributary Main creek from West Fork 46 63 52 56 71 68 52 . of south tributary to junction with the south tributary West Fork of south trib. 7 9 88 59 22 18 28 South tributary below 9 35 15 33 49 34 31 beaver dam In south tributary 0 7 36 62 55 35 24 beaver pond South tributary above 0 1 56 59 51 45 64 beaver pond Lake Fork to beaver pond 0 0 52 42 28 21 24 Beaver pond on Lake fork 0 0 0 0 0 0 1 Lake fork above beaver 0 0 0 0 0 0 0 pond ! Spring Fork 0 0 215 207 160 169 144 Total 335 464 571 I 520 473 I 394 370 TABLE 3: Number of spawning sockeye salmon (Oncorhynchus nerka) in the stream system above Black Lake 1984. I -34 - Location Date -1984 8/18 8/21 8/27 8/31 9/4 9/7 Mouth of creek to West 1 4 1 0 0 0 Fork of south tributary Main creek from West Fork 0 4 2 2 0 0 of south tributary to junction with the south tributary West Fork of south trib. 0 2 0 1 0 1 South trib. below 0 0 0 0 0 0 beaver dam In south tributary 0 0 0 0 0 0 beaver pond South tributary above 0 0 0 2 2 2 beaver pond Lake fork to beaver pond 0 0 2 0 0 0 Beaver pond on Lake Fork 0 0 0 0 0 0 Lake fork above beaver 0 0 0 0 0 0 pond Spring Fork 0 0 4 4 4 3 Total 1 10 9 9 6 6 TABLE 4: Numbers of spawning chum salmon (Oncorhynchus keta) in the stream system above Black Lake in 1984 9/9 0 0 1 0 0 3 0 0 0 2 6 Location Mouth of creek to West Fork of south tributary Main creek from West Fork of south tributary to junction with the south tributary West Fork of south trib. South tributary below beaver dam In south tributary beaver pond South tributary above beaver pond Lake Fork to beaver pond Beaver pond on Lake Fork Lake Fork above beaver pond Spring Fork Total -35 - Date -1984 10/29 11/1 1 1 3 0 7 3 8 5 30 19 4 7 6 0 59 35 L---------------------------------4-----------------+-----------------------~ TABLE 5 Numbers of spawning coho salmon (Oncorhynchus kisutch) in the stream system above Black Lake, 1984. I -····· -· Location Area Date of Method of Coho (0+) Coho (1+) Coho l+ Dolly Varden (m2) Estimate Popn. 95% ---=--· Fork Popn. ';1)4 Density I Condition Coh~-"o+ ~ 1':1)4 1uens1ty Estimate Density 1984 Length Estimate Confidence no. fish Length Estimate Confidence no. fish factodK) Patio Estimate Confidence no. fish Intervals I m2 Intervals I m2 Intervals I m2 Black Lake 914 to Schumacher < 60mm 5,105 4,296 to -) 60mm 2,746 2,486 to -1.15 0.53 --- 919 & Eschmeye 6,289 3,071 --·-·-----1-- Section A 2,116 9/2 to Peterson <60mm 3,924 3,390 to I. 85 > 60mm 538 424 to 0.25 1.20 0.14 ---9/3 4,587 705 Section B 1,790 9/l to Petersen <60mm 3,555 3,054 to 1.99 > b(}nm 840 660 to 0.47 1.20 0.24 -9/2 4.197 1,068 ···~·-·~-~~ ~-·· 0.19 Section C 1,469 8/)0 to Petersen < 60mm 1,014 7 50 to 0.69 >60mm 286 192 to LIS 0.28 -- 8/31 1, 369 424 --· Section D 692 8/)0 to Petvrsen < 60mm 708 518 to l. 02 ">60mm 132 15 to 0.19 1.15 0.19 -- 8/31 921 196 •.. Beaver Pds. 725 8118 to Schumacher < 60mm 574 468 to 0. 79 > 60mm 414 362 to 0. 57 l. 15 0. 72 101 73 to 0.10 s. side nr. 8/21 & Eschmeye 745 482 164 creek entr. to Lake --··-·- Beaver Pds. 904 8126 to Schumach < 60mm ~.499 2,112 to 2.76 > 60mm 652 552 to 0.72 1.16 0.26 232 172 to 0.21 on Lk. Fk. 8/29 & Esctune 3,063 795 357 ..• Beaver Pds. 1 '450 8/26 to Schumacher ( 60nuu 4,87J 4' 128 to 3.36 )' 60mm 1,041 919 to 0.72 1.22 0.21 896 705 62 on s. fk. 8/29 & E,;cluneye 5,948 1,201 1 '2 32 . }'ABLE 6: Population Estimates of juvenile rearing salmon ids in Black Lake and the stream system above the lake in 1984. I "' 1\l llQ m w "" I Date of Location Estimace 1981 Black Lake 9/7 to 9/15 ·~-------- Section A 9/3 to 9/4 Section B 8/8 to 8/9 Section C 8/29 to 8/30 Section 0 9/1 Beaver ponds 8/15 to s. side nr. 8/19 creek entr. to Lake Beaver ponds 8/30 tO on Lake Fk. 9/l -----~--------~-----····-··---.. ~ -------~--···---·-,---~~~--~ ·~·--·--~·· Method of ~-~-Coho (0+) Coho (l+) Coho 1+ Estimate ---~---~----· -----~---~ ' Popn. 95% Density Fork Popn. 95% Density ork Condit~~} to Length Estimate Confidence no. fish ength Estimate Conf idtmce no. fish Factor( Coho 0+ Interva 1 I m2 1 m2 Ratio Schumacher < 6Smm 2,394 i. 930 to -> 65nun 2,628 2,196 to -1.12 1.09 & Eschmeyer 3. 154 3,271 Pe~-~r~-;,~~~~~--1,780 to 0.92 >60mm 372 240 to 0.17 1.13 0.18 2,165 341 ··-------------- Pet Percentage of marked fhh recaptured too low to gl ve an accurate estimate Pet -l --> I Petersen Juvenile fish of very low density -insufficient to complete mark and recapture eKperiment Schumacher < 55nun t. Eschmeyer Schumacher <bOmm & Eschmeyer -----· 588 471 to 0.81 > 55nun 504 440 to 0.69 787 593 -----~-~~~p 777 5 6 > 60nun 442 344 to 0.49 1. 3 615 Comparative table of x·esident 1earing juvenile sallnonids in Black Lake and stream system above the lake in 1981. 1.15 0.86 ' o_s7 "o II Dolly Varden Popn. 95% Density Estimate Confidence no. fish I m2 low -- ---I - 50 46 to 0.07 55 82 74 to 92 -38 - Location Water Area Densities 1m2 for respective juveniles m2 0+ coho 1+ coho Dolly Varden Section A 2,116 1. 85 0.25 - B 1,790 1. 99 0.47 - c 1,469 0.69 0.19 - D 692 1.02 0.19 - Beaver ponds 1,010 0.56 0.41 0.10 near Lake Beaver ponds-1.106 2.26 0.59 0.21 Lake Fork Beaver ponds-1,450 3.36 0. 72 0.62 South Fork TABLE 8: Summary of the densities of 0+ and 1+ juvenile coho and juvenile dolly varden in various sections of the stream system above Black Lake. Location No. of fish Regression Equation Correlation Condition sampled (N) Log W = Coefficient (r2) Factor(K) Black Lake 102 = 2.8721 log 1 -4.6964 0.948 Section A & B 85 = 2.8962 log w -4. 7243 0.955 Section c & D 84 = 2.6582 log 1 -4.2917 0.931 Beaver ponds -94 = 2.6663 log 1 -4.3200 0.936 s. side nr. mouth of creek Beaver ponds on 91 = 2.7554 log 1-4.770 0.922 Lake Fork Beaver ponds on 102 = 2.5788 log 1-4.1275 0.892 South Fork TABLE 9: Summary of regression statistics and Fulton's condition factor (K) for 1+ coho in a number of areas of the stream system in and above Black Lake. August/September 1984 1.15 1. 20 1.15 1.15 1.16 1. 22 -39 - Location Population estimate and 95% C.E. Density 111m2 Coho 1+ > 55mm Dolly Varden 1 + > 55nnn Coho 1+ Dolly Varden Trap Bay Below 2 7 < 92 < 157 33 < 55 <. 77 .78 .47 --- -Within 62<176 < 291 5<26<47 1. 78 .26 - ---Above NE NE NE NE Kadashan Upper Pond Below 172<2"26 < 280 87< 246<405 .78 .85 739(9oi<1o26 - -Within 321<739<1158 1.02 .84 ----Above 359<505< 650 213<352<491 3.66 2.55 --- - Kadashan Lower Pond Below No estimate -stream channel dry Within 375<544<712 0 1.84 NE --Above 390<447<505 152<430<708 4.52 4.34 --- - Blind Slough Dam 2 Below No estimate Within 128<164<319 0 .60 NE - -Above 67<ll3<158 0 < 32 (._ 64 5.14 1. 45 - - - - Dams lA & lB Below 82-<172(262 NE 2.02 NE --Within 278<459<640 NE . 7 4 NE --Above 26 < 3209 2 1. 39 .02 -- TABLE 10: Population estimates and densities of fish below, within, and above beaver ponds in Trap Bay, Kadashan, and Blind Slough sampling areas, southeastern Alaska, 1982 Adapted from Bryant, M.D. in press. The role of beaver darns as coho salmon habitat in southeast Alaska streams. Proceedings of the Olympic Wild fish Conference, National Park Service and Peninsula College, Yort Angeles, Washington. March 1983 ,( H Location Trap Bay, July 1981 Beach Creek Bambi Creek Porcupine Creek, July 1981 Main stream 350 m 500 m 700 m Staney Creek, July 1979 Tye Creek Toad Creek Aha Creek Knob Creek Sashin Creek, July 1966 Upper Middle Lower Funny Creek -40 - Dens it} Coho (1+) .43 .15 .67 .64 .76 .51 .27 .15 .55 . 37 1.15 .97 2.35 (No. fish/m 2 ) (1+) I Dolly Varden~ .76 .07 .44 .07 .10 .40 .31 .30 .28 TABLE 11: Density estimates of juvenile salmonids in southeast Alaska Adapted from Bryant, M.D. in press. The role of beaver dams as coho salmon habitat in southeast Alaska streams. Proceedings of the Olympic Wild Fish Conference, National Park Service and Peninsula College, Port Angeles, Washington. March 1983. -41 - Location Appro~ area Coho m 0+ 1+ Zone I (includes Sec. A & B) 17,869 34 '300 6,430 Zone II (includes Sec. C & D 4,900 4,180 931 but excludes beaver ponds) Beaver Ponds -south side near 725 574 414 creek entrance to lake Beaver Ponds -on Lake Fork 904 2,499 . 652 Beaver Ponds -on South Fork 1,450 4,873 1,041 Totals = 46,426 9,468 95% confidence intervals 39,390 to 7,502 to 55,615 12 '187 TABLE 12: Approximate total numbers of rearing juvenile coho for sections of the stream above Black Lake Chemical Parameters May 23, 1983 March 26, 1984 3.5 m 7. 0 m 3.5 m 7.0 m Total phosphorus 3.7 3.8 3.0 4.7 (ug/L -1 as P) Total filtered phosphorus 5.3 5.7 3.5 4.4 (ug/L-1 as P) Filtrate reactive phosphorus 2.3 2.1 1.8 3.0 ' (ug/L-1 asP) Kjeldahl Nitrogen (ug/L-1 as N) 48.9 51.5 79.2 80.5 Nitrate and Nitrite 36.1 37.3 46.5 45.9 (ug/L-1 as N) Ammonia 6.2 5.4 7.0 11.6 (ug/L-1 as N) TABLE 13: Chemical data for Black Lake at spring overturns, 1983 and 1984 Date of Sample August 30, 1982 April 27, 1983 May 23, 1983 __jMarch 26, 1984 nos/m2 Ave. nos/m2 Ave. nos/m2 Ave. nos/mL Ave. Zooplankton 11m H 2o nos/m3 size lOrn H20 nos ,m3 size lOrn H20 nos m/3 size 10m 120 nos/m3 size column (mm) column (mm) column (mm) column (mm) Cladocera Bosmina 9,214 838 0.31 5,434 543 0.32 4,875 488 0.34 171 17 0.26 longirostris Holopedium 338 31 0.49 --------- Chydorinae 147 14 0.34 51 6 0.30 153 15 0.35 84 8 - Cladoceron 4,521 411 -120 14 -2,155 215 ---- eggs CoEeEoda Cyclops sp. 510 47 0.51 rare rare -31 3 0.58 --- Diaptomus sp. 127 12 1. 79 --------- Nauplii 1,592 145 -161 29 -255 26 ---- Rot if era Kellicottia 208 17 -117 12 ------- longispina Asplanchna sp. 401 37 -168 17 -596 60 ---- TABLE 14: Zooplankton abundance and average size in Black Lake, summer 1982, spring 1983, and spring 1984. Counts from teh average of two hauls. -43 - III. WILDLIFE OBSERVATIONS Introduction This section reports upon examinations of terrestrial habitat for evidence of mammal use, continues a log of mammal sightings, and identifies, as closely as possible, beaver and black bear populations in the study area. Methods As described in earlier reports, mammal observations were recorded on a daily basis. During the course of fisheries and hydrological data gather- ing excursions, stream banks were closely examined for mammal sign. This sign included tracks, scats, den and bedding sites, feeding areas, access slides -in the case of beaver -and other indicators of animal movement, such as hairs caught on overhanging logs, flattened brush, overturned rocks and logs. Time constraints precluded systematic probes into the brush at the base of the valley headwalls, but these areas were visited at least once during this trip. While minnow-trapping, logging escapement counts, and collect- ing hydrological data, approximately 16 trips from Black Lake up to the Spring Fork upwelling -including all three tributaries -were completed. In addition to these stream-intensive walks, one trip was made up the val- ley to the upper South Fork basin in order to assess current mammal activ- ity in that area. Bi-weekly hikes were taken back from the stream banks above Black Lake all the way up to the South Fork pond and the Lake Fork pond. One trip was made to the falls of Black Bear Creek. Alpine slopes above Black Lake and the lower end of Black Bear Lake were regularly scrutinized with binoculars for deer and bear. Black bear tracks were measured to identify individual animals. Three to five front tracks on firm ground were measured across the widest point of the pad and averaged. This figure enabled us to distinguish one bear's tracks from another. Observation of tracks and feeding areas indicated -44 - approximate bear territories. Wolf tracks were measured and recorded in the same fashion. As noted before, deer, beaver, and mustelid tracks were observed primar- ily for frequency and location, with no attempt at identifying individuals or their territories. Beaver activity was closely observed by means of regular hikes around the margins of the three major ponds in the system above Black Lake. All dams, new and· old, were monitored closely for signs of building activity. The access slides along the shores of Black Bear Creek above Black Lake were examined daily. Specific Observations Black Bear (Ursus americanus) From 8/18 to 9/11/84 the tracks of one small black bear were commonly found throughout the study area from lower Black Lake up through the lower beaver pond to the Forks area and into the upper South Fork basin. This bear roamed widely and regularly in the region above Black Lake, with heavy feeding sign consistently found on the beaver pond fringes where skunk cabbage roots (Lysichiton americanum) were excavated over large areas. In addition to this primary fall food source, carcasses of sockeye salmon were frequently found hauled out and partially eaten throughout the Forks region and even as far as 100 meters back into the brush up above the South Fork pond. This small bear (9.3 em track) has traveled and fed extensively in the upper South Fork basin, as well. On 9/5 fresh 9.3 em tracks were followed up into this basin and widespread skunk cabbage digging was identified in the marshy area immediately below the small, lowest pond in the basin. On returning to the lower valley on 9/5, I followed fresh 9.3 em tracks down the game trail to the vicinity of the South Fork pond, where the small b~ar was seen heading into the brush toward the Spring Fork. The small black bear has been feeding on skunk cabbage and berries in back of the lower beaver pond as well, with casual trails criss-crossing the -45 - sedges in several places; the bear was seen on 8/24 during a minnow trap- ping operation. This ·bear is very sleek and energetic, as can be seen by its extensive roaming of the study area. The only other black bear sign occurring in the study area was the tracks of a somewhat larger bear (11.0 em.) seen below Black Lake along the stream bank on 8/18. This bear's tracks were also seen in the dewatered mud fringe of the South Fork pond on 8/21. At no other time were signs of this bear encountered. It is likely this bear was a casual visitor to the area and was gone by the time we arrived. In summary, as of 9/11 there was one small black bear with a 9.3 em. track resident in the study area, roaming widely throughout the system, and feed~ ing primarily on plants, in particular skunk cabbage roots. Beaver (Castor canadensis) An extensive walk of the Black Bear Creek system above Black Lake on 8/18 revealed a low level of beaver activity, generally, with two exceptions. The new dam on the Spring Fork adjacent to the Lake Fork dam, under con- struction in late March, has been added to and is nearly complete, with fresh salmonberry cuttings woven into the larger framework of the structure and small stones and mud packed against the upstream side. There was increased beaver sign around the lower beaver pond and in the slow-moving, deep section of Black Bear Creek between Black Lake and the Forks. This increased beaver use coincides with more sign along the West Branch of the South Fork. The most dramatic change in beaver activity occurred on the South Fork pond, where.on 8/18 a six foot wide break in the dam, midpoint in the most massive breastwork section, had allowed for serious dewatering of the pond, with the water level some two feet lower than seen in late March. Some fresh beaver tracks were seen on the margins of the pond, in freshly ex- posed mud, and several scent mounds had been recently used, but there was no fresh dam work noted, not even the most cursory signs of food-gathering prior to winter. r -46 - Beaver activity in the Lake Fork pond continued at normal levels, with freshly scented mounds on the perimeter of the pond; fresh 3 -5" alder cuttings around in back of the pond; alder, salmonberry and Vaccinium spp. cuttings floating up against the dam in many spots; fresh dam work in sev- eral places, serving to raise the pond level marginally higher than seen in March. One large scent mound in mid-pond was found to be heavily used, as has been the case for four years, and the area was redolent of castoreum used in scent-marking. The lower beaver pond, just above Bl·ack Lake, was well-used by beaver, with fresh dam work and many small trails radiating out from the pond into the skunk cabbage patches and dense Vaccinium stands circling the pond. The many access slides on the stream banks above Black Lake appeared to be well used, with fresh tracks commonly seen in the mud and trails leading back into the feeding areas edging the stream. Sign in the upper South Fork basin was minimal, with little vegetation piled in the ponds for winter food supply, and several scent mounds which have always been well-scented in the past now appeared to be abandoned, with small plants springing up out of them. This reduced evidence of beaver presence coincides with the departure of beaver from the South Fork pond and leads to the following speculation on this behavior. South Fork Pond beaver Beaver in the past year came into this area in a flurry of activity, erect- ing a massive dam, excavating long and deep runways in the pond bottom, piling up food, and creating what appears to be a lodge in mid-pond. Now, mysteriously, they are gone from this pond. Seve~al possibilities were examined as causes for this egress: 1. trapping 2. increased predation 3. diminished food supply -47 - Beaver harvest reocrds were examined in Ketchikan with the help of Chris Smith, ADF&G. Approximately two hundred beaver were trapped leg- ally on Prince of Wales Island last winter, but none were reported from the Black Lake region. There was no evidence to support the presence of trappers; no tracks, no trails, no trap sets. Practically speaking, it is unlikely a trapper would confine activities to the South Fork pond without t!apping the remainder of the system as well. In light of these thoughts, it is extremely unlikely the South Fork pond beaver have been trapped. Their departure is probably on their own initiative, as pre- dation to any large extent is also not supported by sign. Wolves continue to be casual visitors to the Black Bear valley, with no sign in evidence in late March and only one set of tracks seen in August ~ September. Limited food supply is the most likely factor in the movement of beaver away from this pond. Small amounts of various species of food plants oc- cur within the pond and close by, but at present, gathering of enough food to support a small family group of 2 - 8 animals would require significant effort. It is thought these beaver have returned to the mainstream sec- tion below the forks, where sign is heavy and food is plentiful and read- ily accessible. As time passes, pioneer species of plants will encroach upon the favor- able habitat created by the opening up of the. forest by the pond, leading to re-establishment of beaver in the South Fork pond. In summary, the beaver population in the Black Bear study area presently appears to be stabilized at an estimated 12 -20 animals, comprised of two family groups. One group resides in the lower beaver pond and the deep, still waters above Black Lake; the other group is located in the Lake Fork -upper Spring Fork area, with the few beaver in the upper South Fork basin probably associated with this family. The expansionary signs noted in the past two years appear to be diminished, due primarily to availability and location of feed. Field work this sum- mer confirms the importance of the beaver ponds in the rearing of juvenile coho and dolly varden. -48 - In the interest of preserving the beaver and their ponds, protective measures should be addressed. In addition to the easier access to these beaver a powerhouse road would provide, the downturn in the local economy has increased Lake area trapping, further threatening this population of beaver. These animals could easily be eliminated in a short time by a skilled trapper. Perhaps the Alaska Dept. of Fish and Game should be ap- proached with a plan to restrict trapping in this basin. Deer (Dama heminionus) Deer tracks were seen on 8/18 in the clearcut by lower Black Lake. No other sign was opserved until 9/5 when tracks, scats and evidence of brows- ing was seen in the upper South Fork basin. On this day, five adult deer were seen grazing on the slopes above the basin. Deer seem to be us this basin somewhat more than in past late-summers during the Black Bear study. A trip to Black Bear Lake on 9/6 revealed heavy deer sign at the exit of Black Bear Lake and in the meadows surrounding the cabin at the head of the lake. Tom Cogus (USFS-Graig) says deer populations are up on Prince of Wales Island this year. A pilot from Westflight stated that deer hunters have been taking "a lot of deer" out of the Black Bear Lake area in the early days of the hunting season. On 9/6 one adult deer was seen grazing above Black Bear Lake in an alpine meadow. Wolf (Canis lupus) As in past reports, it can be said that wolves are intermittent visitors to the study area. On 8/28 a wolf scat was found on a log in the Lake Fork pond, and on 9/5 an old set of tracks left by a large, solitary wolf were noted in the upper South Fork basin, skirting the lower dam. Wolves in this basin are probably related to deer presence. Marten (Martes americana) On 8/26 a marten scat was found on a log in the Lake Fork pond near the outflow to Spring Fork. Mink (Mustela vision) Mink sign was commonly seen on the muddy fringea of Black Bear Creek above -49 - the lake, with the greatest frequency of track sightings noted in the Forks area, up to the Spring Fork upwelling and across to the South Fork pond. Otter (Lutra canadensis) Otter sign continued to be sporadic and unpredictable. On 8/18 several haulout sites along Black Bear Creek below the Forks were identified. On 8/21 otter sign was seen on the Spring Fork just above the Lake Fork pond. Otter come and go in this system with no pattern to their movements, as is common amongst this species in Southeast Alaska. (Bob Wood, ADF&G) Little Brown Bat (Myotis lucifugus) Bats were seen on several occasions in front of camp on upper Black Lake in the late evening hours, and along Black Bear Creek below Black Lake. Mammal Observations 10/29 -11/2 1984 Winter conditions prevailing on this trip greatly enhanced mammal tracking, revealing an abundance of s seldom seen at any other time of the year. The study area was well-traversed on foot, including two complete hikes the length of upper Black Bear Creek, all tributaries, and one hike up to the upper South Fork basin. Both ends of Black Bear Lake were examined as well. One hike was taken down the north side of the Lake Fork from the powerhouse site to the edge of the Lake Fork pond. During these hikes the followi'ng mammal sign was observed: Black Bear (Ursus americanus) 11.3 em. tracks were found throughout the valley above Black Lake. This is the same bear tracked through the study area in the summer. Sign was heaviest along the South Fork above the beaver pond and in the vicinity of the Forks of Black Bear Creek, with random tracks seen in the South Fork basin and up the Lake Fork toward the falls. This bear has been feeding on coho along the South Fork and the Spring Fork. Tracks of a second, larger bear were seen on 10/29 heading toward Black Lake along the logging road. These tracks were also seen on 10/31 in the old growth forest border Black Bear Creek in the vicinity of the pro- -50 - posed powerhouse site. This bear is a late-comer to the study area, as no tracks of this size (12.0 em.) were seen in August or September. Beaver (Castor canadensis) The center of beaver activity continues to be in the Lake Fork pond area, with fresh cuttings evident in several places, and a large winter food supply gathered together in mid-pond, where beaver have stored caches over the past four winters. Beaver activity in the lower stretches of Black Bear Creek above Black Lake was much reduced from September. The pond in the upper South Fork Basin was frozen over and covered with several inches of fresh snow, precluding the observation of winter food caches, but some fresh Vaccinium cuttings and peeled sticks were washed up against the dam, indicating continued presence of beaver in the pond. The small dam on Spring Fork showed continued building, and is near c~- plete, at about two feet in height. The dam on the South Fork pond still appears to be abandoned, with the six-foot wide break still un-repaired, leaving the pond level even lower than that seen in August. Marten (Martes americana) Marten tracks were seen commonly in virtually every part of the both along the creek and up into the deep forest along the Lake Fork and into the upper South Fork basin. As an indication of the prevalence of marten tracks, on 10/31 over 50 sets of tracks were seen while walking up the valley above Black Lake. Even though marten move around a lot, this abundance of sign is indicative of a healthy marten population in the study area. Deer (Dama heminionus) More deer tracks were seen on this trip than at any time since mammal tracking began i~ late 1980. Tracks were seen on the logging road leading to Black Lake on 10/29. Tracks were seen near the Forks; on the lower end of Black Bear Lake; near the proposed powerhouse site; both on the headwall leading to the upper South Fork basin and in the basin; and in the forest on the south side of Black Lake. Clearly the deer are more -51 - plentiful here than at any time in the past five years. Mink (Mustela vision) Limited sign seen along the edge of Lake Fork pond and Spring Fork above the Forks of Black Bear Creek. In summary, beaver activity has slowed with the early advent of winter. Lake Fork pond is the hub of beaver activity in the valley above Black Lake. Deer are present in the valley in much larger numbers than ever before. There are presently two black bears in the study area. Marten are present in all areas above the bridge over Black Bear Creek. Mammal Sightings Black Bear 8/24/84 -in back of the lower beaver pond eating berries 9/5/84 -in brush above South Fork pond headed toward Spring Fork Deer 9/5/84 9/6/84 Beaver -five individuals on slopes above South Fork basin -one individual on heathery ridge above Black Bear Lake 8/21/84 -one swimming by Upper Black Lake thermograph site 8/29/84 -one swimming in Black Bear Creek opposite lower beaver pond. -52 - CITATIONS Bishop, D.M., A.M. Milner and L.A. Smith. 1982a. Biological-ecological investigations on the Black Bear Creek system near Klawock, Alaska. Environaid, Juneau. Report to Harza Engineering Co. for Alaska Power Authority. 173 p. Bishop, D.M., A.M. Milner and L.A. Smith. 1982b. Late summer and fall observations in ~pper Black Bear Creek, southeastern Alaska. Environaid, Juneau. Report to Harza Engineering Co. for Alaska Power Authority. 26p. Bishop, D.M., A.M.Milner and L.A. Smith. 1983. Further investigations on the Black Bear Creek system near Klawock, Alaska. Environaid, Juneau. Report to Harza Engineering Co. for Alaska Power Authority. 90 p. Bryant, M.E. Distribution of salmonids in the Trap Bay Stream basin. In symposium on old-growth forest/fisheries relationships. American Inst. of Fishery Research Biologists. Juneau, Alaska. Apr.l2 -14, 1982. Bryant, M.E. In press. The role of beaver dams as coho salmon habitat in southeast Alaska Streams. Proceedings of the Olympic Wild Fish Conference Natl. Park Serv,ce and Peninsula College, Port Angeles, Wash. March 1983. Carlander, K.E. 1969. Handbook of Freshwater Fishery Biology, Vol. I. Iowa State University. 752 p. Chapman, D.G. 1951. Some properties of hyperzeometric distribution with applications to zoological sample censuses. U.Cal. Publ.Stat. l• 131-160. CH2M-Hill. Black Bear Lake Hydrology Report. Anchorage, Ak. 2/12/81. Cogut, Tom. U.S.F.S. Craig, Ak. Pers. comm. 1984. Dolloff, Andy. Forestry Sciences Laboratory, Juneau. U.S.F.S. October, 1984. Jones, Will. Pers. comm. Proprietor of The Prince of Wales Lodge, Klawock, Alaska. 1984. Koenings, Jeff. F.R.E.D. Division, A.D.F.&G. Soldotna. Pers. comm. 1983. Murphy, M.E., F. Thedinga, K.V. Koski, and G.B. Grethe. A stream ecosystem in an old-growth forest in southeastern Alaska: Part V. Seasonal changes in habitat utilization by juvenile salmonids. In symposium on old-growth forest/fisheries relationships. American Inst. of Fishery Research biolobists. Juneau, Alaska. Apr. 12 -14, 1982. Schumacher, F.X. and R.W. Eschmeyer. 1943. The estimate of fish population in lakes or ponds. Journal Tenn. Acad. Sci. 18 228 -249. Smith, Chris. A.D.F.&G. Ketchikan, Ak. Pers. comm. 1984 Straty, R.R. 1960. Methods of enumerating salmon in Alaska. Transactions 25th North American Wildlife Conference. 286 -297. Wood, Bob. A.D.F.&G. Ketchikan, Ak. Pers. comm. 1984