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HomeMy WebLinkAboutAPA66I ' .. J I I I I I I I I ) I I I I I d I ~ . ........ DRAFT E f f E: c t s o f V a r i o u s T e m p e r a t u r e R e g i m e s on the Incubation of Susitna River Chum and Sockeye Salmon David B. Wangaard Carl V . Burger ... U S F I s h a n d W .I I d I I f e S e r v i c e National Fishery Research Center A I as k'a F 'l e I d StatIon Anchorage, Alaska U NIVERSIT t ALASKA • AAC'fi C E NVI RQ;,, , r,L INFORMATION AN > .'H i:R 70i " ,.,r .... H ANQtCY.GE. AX. 99501 ·; • •~ ·.· DRAFT Effects of Various Temperature Regimes on t he Incubation of •· Susitna River Chum and Sockeye Salmon • D avi d B . Wa n gaar d Carl V. Bur ge r US Fish and Wildlife Service National Fishery R es earch C e nter Alaska Field Station Anchorage, A l aska c.s. FIS H & WII.OLIFE SI::RVIC E AUGUS T 1983 DRAFT Abstract A study was und ertake n to assess the pote ntial effects of temperature alteration resulting from hydroelectric develo~m ent on sa lmon incuba- tion rates in the Susitna River, Alaska . Chum (Oncorhynchus keta) and sockeye (9..:._ nerka) sal mo n egg s from Slough 11, Upper Sus i tna River, were co l lected and fertil i zed on three occasions du ring September, 1982 . The eggs were i ncubated in our laboratory at four different temperature regimes until alevins achieved complete yolk absorption . The four regimes simulated temperatu res in: (1) th e main-stem Susitna River; (2) Slough 8A (a known spawning area); (3) a ~ regime l°C colder than in Slough 8A; and (4) a constant 4°C . We used the concept of average temperatu re of each regime for sub - sequent comparison$. Average temperatu re for the four regimes described above were 2.1 , 2.9, 3.9, and 4.0°C, respectively. Com- plete yolk absorption was delayed by up to two months at our coldest regime , as compared to the regimes having average temperatures of 3.9 and 4 .0°C. No meaningful differences were obs erved betwee n mean length of alevins reared in the four regimes. A regr ession equa tion is presented which evaluates development rates at know1: tempe ratures. It should be possible to predict the number of day s requ ired for Susi t na chum and sockeye to hatc h a nd to attain complete yolk absor p- tion if the average · incubatio n temperature of the spawning area can be specified. I It' . I -I •I 6 • --;· \ • • • • • • • • • Effects of Various Temperature Regimes on the Incubation of Susitna River Chum and Socke ye Salmon Introduction DRAFT Construction of dams and their resulting reservoirs are known to alter dow n- stream temperatu re regimes in certai n rivers and streams. Hydro~lectric development is in the planning or construction stages in several Alaska n rivers. Thermal effects from dam and reservoir operation in Alaska should be most pronounced during the fall and spring when the river's natural rapid cooling and warming may be modified by reservoir discharges. Thus, sal mon eggs a nd alevins incubating downstream of a hydroelectric project may experi- ence alterations from historical water temperatures which , in Alaska, gen er- ally range from 0° to 8°C. Much researc h has been conducted on t he incubation of sa l mo n eggs. While it is kno wn that temperature changes within the range 0° to SoC are more pro - nounced upon deve lopment rates than those between 5° and 10°C (Barns 1967), 1 ittle addit i ona l information is avai'lable on egg incubation at temperatures less tha n 4°C (Dong 1981 ; Raymond 1981; Alderdice and Velson 1978). There is a regional need for this information as Alaska n salmon often spawn in water temperatures approaching or already less tha n 4°C. There is a further need for this info r matio n for Susitna River stocks due to the hydroelectric dams pro posed for Susitna Rive r mi les 153 a nd 184. • • 2 DRAFT Th e Susitna River in southcentral Alaska (Fig. 1) dr ains about 19,000 mi 2 i nto Cook Inlet . It is the s ixth largest drainage i n Alaska and supports a fish ery resource tha t inc ludes fi ve species of salmon, a few non-anadro- mo us salmonids , and other resident species such a s grayl i ng (Thymallus ar~tic~s ) and burbot (Lota lata). A host of s t udies have bee n undertaken to evaluate potential im pacts of hydroelectric developme nt o n fish and wildlife . Our study was designed to investigate the incubation of two local stocks of sal mon unde r varying temperatu r e regimes. •OUIO T I&I. o uo sort a I \ • ----~-..... S TUDY 4AI!A Figure 1 . The Susitna Rive r in southcentral Alaska a nd the l ocatio n of t wo sloughs (used by spawning sal mo n ) i n relation to proposed hydro~ electric da m sites . .. · 3 DRAFT Wh il e post-pr oject river temperatures have not bee n fu ll y identified at this time, it is understood that water temp~ratures downstream of the dams will be l ess than pre -pr oject temperatures in the su mm er, and greater tha n pre - proj ect temperatures in the fall an d ea r ly winter. To accurately predict th e ef fe cts of cold-water temperatu re changes on Susitna River salmo n eggs, the following study o bjectives were develo pe d: 1 . Co nst r uct a labo r atory enviro nment to document incubation of salmo n eggs a nd alevins under four t em pera t ure regi mes which simulate: (1) the main-stem Susitna; (2) a s ide -cha nnel sl ough system; (3) a second • slough system differ i ng from t he first by l°C; and (4) a constant temperatur e regime at 4°C. 2. Collect a nd s pawn f i ve to s even pa i rs of chum (O nc or hynchus keta) a nd sockeye(~ nerka) salmo n from a sloug h i n the Upper Susitna on three different dates which include their normal, peak s pa\'l ni ng .:>erio d . 3 . Reco r d the time of egg hatching a nd c omplete yolk absorptio n in temperature units (TU s ) a nd days fo r eac h s pecies incubated und er the fou r t em pe ra ture reg im es i n the laboratory . Measu re lengths and record weight s of alevi ns at time of hatch a nd yolk absorptio n. (Document surviva l and note any abnormal ities duri ng deve l opme nt.) 4. Pr ovide a final report to help pl anners predict how certai n tempera - ture regimes will affect incubation and development of Susitna chu m and sockeye salmo n . .. 4 • •• This study 'Has conducted by the National Fishery Research Center (NFRC), U.S . Fish and Wildlife Service, in cooperation with its Division of Ecologica l Ill Services and the Alaska Department of Fish and Game (ADF&G), Su-Hydro Divi - Ill Ill • sion . Major funding was provided by the Alaska Power Authority. Materials and Methods Well water wa s plumbed into e1ght insulated waterbaths in the NFRC labora- to~y. Water temperature control was achiP.ved in the baths (heating or chilling) before the water flowed into insulated Heath incubators . Control and monitoring of the incuba t or water t emperatures was possible from 0 .5° to 12°C with O.l°C resolution and ±0.3°C a ccuracy . Four temperature reg i mes, each with a replicate, were monitored with a 10-channel temperature data logger. The data l ogger provided hou rl y printouts of water temperature for all eight incubators. The average temperature for 24 hours was used to compute the accumu la ted temperature units (TU s ) for each temperature regime. Thus if eggs were incubating at an average 5°C for 10 days , they would accumulate 50 TUs. Incubators were modified prior to egg collectio ns to prevent water f r om mixing between the two species under s t udy since chum and sockeye salmon were to incubate simultaneously in all eight incubators. Th e s e modifications insured that two wate r lines from a commo n sou rce each fed on l y .four o f eight egg trays in each incubator, thus providing the ability to incubate eac h species independently. Because each water line fed on ly four trays tempera - tures did not vary mor e than O.l°C as water passed th r ough the trays. • n ~ • 5 DRAFT Three egg collections were made for chum and sockeye salmon at Slough 11 (RM 135.3) on the Susitna River (Fig. 1). For each species at least seve n pairs (males and females) were spawned on September 3, 9 and 15. The fertilized ova were brought to our lab . Egg ferti l ization and handling procedures followed the reco n~e ndations of Leitritz and lewis (1980) . • The eggs were me asured out volumetrically i n the lab and distributed ;nto eig ht equ al lots. Eggs were pla ced into plastic rings (10 em diameter x 5 em depth) which were su r rounded by styrofoam withi n the incubator trays. The styrofoam directed wa ter flow through the rings where eggs (average 4 .6 ml eggs/cm 3 ring volume) were held until hatching. Water flow was maintained at about 2.2 Z/mi n throughout the study. Dissolved oxyg en was measured weekly until hatching was completed and then monthly thereafter. Because of thei r l a rger diameter the average number of chum eggs per tray (1,070) was less than the average number of sockeye eggs per tray (1,400). At the conclusion of the third egg collection , four incubators each had three trays of chum and three trays of sockeye eggs representing the three egg takes (Table 1) and the four temperature regimes. The four additional incubators were added with an identical design to provide a complete re pli - cate of the study. Two of the four water temperature regime s used in our study simulated natura l temperatures in two reaches of the Upper Susitna River. The first simulated a thermograph placed in the main-stem Susitna near Gold Creek at river mile 136. We designated this regime as "MS". The s econd regime simulated tempe r- atures recorded by a thermograph withi n Slough BA (RM 125), a known spawning • II 6 DRAFT area f or chum and sockeye . We designated this regim e as ~sz". Incubator water temperatures were adjusted as much as twice weekly during fall and sp r ing whe n the greatest river temperatu re fluctuations occurred. Pe rs onne l from ADF&G, Su-Hydro Divisio n, determined all field water temperatu res. Table 1 . Egg placem~nt within a given incuba- tor during ou r study . (Each i ncuba- tor maintained a specific temperature regime or its replicate .) Tray 1 2 3 4 5 6 7 8 Chum eggs Chum eggs Chum eggs Empty Sockeye egg s Sockeye eggs Sockeye eggs Empty Collected 09/03 Collected 09/0 9 Collected 09/15 Water to drai n Collected 09/03 Co 11 ec ted 09/09 Collected 09/15 Water to drai n A third temperature regi me (designated "S 1") was established as a n inter medi- ary regime betwee n MS and S2. S1 differed from S2 by l °C . The fourt h re- gime !(desig nated 4°) wa s ma intained at a consta nt 4°C for the duration of the study . Because high water inundated Slough 8A du r i ng the winter of ou r study, t he AOF&G thermograph was l ost . Thus, it was necessary to use tempe rature data obtained from 1981-1982 (Trihey 1982) as the new model for Sloug h SA {52). Whe n 50 percent of the egg s had hatched within any given t ray, 30 alevins were removed , anesthetized a nd the n weighed to the nearest 0.01 g a nd me a- 'I • 7 sured (to 0.1 mm) for total length. After 95 percent of th e eggs had hatched in any given tray, the styrofoam water block and rings were removed and 10 alevins were sampled fo r length measurement s each week. Weekly samples co ntinued until the alevins had completed yolk sac absorption. This stage was determined by observing the openi ng along the alevin's ventra l surface which was separated by yolk sac. When the right an d left ve ntral sides had sutured closed ove r the remnant yolk sa c, the alevin was determi ned to have completed yolk abso rption (CYA). A samp le of 30 a l evi ns was removed and measured fo r tota 1 length •t~hen 50 percert CYA ·..,a s achieved . • Data wer e compiled to provide compa r isons fo r time to hatch and complete yo lk absorption in TUs and days. Mortalities a nd abnormalities for each tempera- ture regime and egg collection we re also noted. The eggs within a few incu - bato r trays experienced lethal stresses due to ex pe ri mental errors and local power outages . The partial r esults from thes e trays we re remov ed from an alysis of length, weight and development rate but have been appended to this study (Appendix 1). For descriptive purposes data from replicates and all three egg collection dates were often pooled. When this was done, the raw data was entered into App e ndix 1. A one way a nalysis of vari~nce (Sakal a nd Rohlf 1969) for lengths and weights for each species at 50 percent hatch a nd complete yolk abso rpt ion was per- formed to compare all temperature regimes and egg co l lection dates. If a significant difference was found (P<O.OS) a Du ncan mul tiple comparison test (Nie et al. 1975) was performed to combine statistically similar gJ·oup s (P=O.O l ). • • ' ...... • -• • ~ s DRAFT Growth curves were constructed from ~eekly length measurements to evaluate length with the accumulation of temperatu re units. Comparisons were also made between developme nt rates 1 (at va rious temperatures) for Susitna River chum an d sockeye and those of other chum and sockeye stocks a s cited i n the literature . Results Wate r Temperature Lab water temperature co ntrol was reliable throughout the cou rse of the study . It was not possible to dupli cate diurn al or within -week tempe r ature variations taking place in the field (S usitna River), but a rou~h equivalence was produced during the salmon incubatio n pe riod. Th e rapid temperature decline of the mai n-stem Susitna in the fal l, its long winter period of 0°C, and warming in the sprin9 was simulated by the thermal regime designated MS in Fig. 2. The cola~st temperature we cou ld main tain was 0.4 to 0.5°C. The water bath would begin to freeze if we attempted to maintai n temperatures below 0.4 to 0.5°C. Because complete yolk abso rption was achieved faster in S2 than in Sl, the t•c temp erature difference was ma intained through late April only. We used intermitte nt reports from the fie ld to esti mate subse- quent temperatures for Sl. The accumulated temperature units for all four temperatu r e regimes a nd fo r the first and third egg collections (September 3 and 15) ar~ presented in Figs. 3 a nd 4. The majo r difference betwee n the two egg collectio n dates 1 Development rate i s defined as the reciproca l of number of days from fe rtili zatio n to spec ific stage, such as complete yolk abso rption, mu1t-; ... 1;n~ ~.. .. lnnn w 0 UJ a:: :::::J 1-< a:: UJ c.. X UJ 1- a:: UJ 1-< :» Figure 2. u 0 (J) 1--:z :::::J UJ a:: :::::J 1- 9 11 • -------52 2 ··································•"' 1 II 21 SCP 48 S1 9il I BB 1Cll 148 I Sl 181! 2BI1 229 2411 2511 23!Jl..N 3!11 OCT 1CN DEC JAN FEB MAR APft AA Y DAYS FROM FERTILIZATION Temperatu re regimes for the Susitna Rive r egg incubation study which simulated the main-stem river (MS), Slough 8A (52), an intermediate regime (Sl), and 4°C Constant (4°). Regime s were plotted from 3 September 1983, the first e~g collection period when ova of chum and sockeye sal mon were fertilized. < ~ a:: ~ 4 X UJ ,_ CJ UJ ,_ < ...J :::::J X :::::J u u < 28 48 68 81! 11!8 121 Hll ISS IBB 229 229 2411 258 2911 3!11 liE~ OCT NOV DI!C JA N FE ll WAR A P A li AR J U H DAYS FROM FERTILIZATION figure 3. Accumulated temperature units at four different temperature regimes for the Susitna Riv er eg g incubation study. Data were plotted from 3 September 1983, the first of three egg collection dates 'Nhen chum and sockeye ova 'Here ferti 1 i zed. The four regimes simulated the Susitna main stem (MS), Slough 8A (52), an int c r ~~diat e regime (S1), and 4°C Constant (4°). 10 occurred within the mai n-stem temperature regime. Due to the d ecli ni ng water temperature, eggs from the third collection that were i ncubated in the main- stem thermal regime required 88 days to reach 200 rus, ,,hile eggs from the first collection period required only 31 day s to reach 200 TU s . u 0 Cfl 1- z ~ lJJ 0::: ~ 1-< 0::: lJJ a.. ::::E UJ 1- CJ UJ ' 1-< ~ ~ X ~ u u < • S1 .· 21 .a 61 85! I ail I aJ I~ : C8 I !II 2lJ1 22B 2 4S a38 281i1 3!11 SEll OCT HOY OI!C .JAM 'EB WAll APR WA-T .JUN DAYS FROM FERTILIZATION Figure 4. Accumulate d temperature 'Units at four different temperature regimes for the Susitna River egg incubation study. Data wer e plotted from 15 September 19 83 , the third of three egg collecti on dates when chum and sockeye ova were fe rtilized. The four regimes simulated the Susitna mai n stem (MS ), Slough SA (S2), an i nt e r mediate regi me (Sl), a nd 4°C Constant (4°). Chum Sal mon Five of the 24 incubator trays containing chum salmon were eliminated from analysis of gr owth and survival due to uncontrolled lethal stresses. The~e represented Slo ugh 2 (fi rst a nd second egg collections) and the 4°C· Constan t 11 ~~~~? :.... • • ;l • • • : replicate for all three eg q collections. When 50 perce nt or mo re of the egg s remained viable howev~r, the subsequent data from those trays was included in the evaluations of time to hatc h and complete yolk abs o r ption. Incubation timing and survival: Computations of the average temperature (for ea ch regime) to various develop- menta l stages allowed fo r standardized comparisons between study tempera- tures. The average temperature to complete yolk absorption showed the co lder to warme r t rend between the mai n stem, Sl, 52 and 4°C Consta nt temperature reg ime s (Table 2). Table 2. Average water temperature during incubation of chum eggs and alevins to 50 percent hatch and complet e yolk absorption in four temp erature regi mes. (Data were pooled from replicates and egg collections.) Temperature regime Main stem Sl 52 Constant 4°C Average water temperature (°C) 50 Percent hatch Complete yolk absorption 1.7 2.~ 3.6 2.9 4.6 3.9 4.0 4.0 The days r eq uired from egg fertilizatio n to 50 percent hatc h and complet e yolk absorption {Append ix 1) is inversely propo rti o nal to increases in tem - pe r ature betwee n the f our temperature regi mes (Fig. 5). ~ggs required abo ut 61 more days to reach 50 perce nt hatch and alevins required 70 more days to comp lete yo lk absor pti o n in the main-stem temperatures, as compa r ed to t he 11 replicaLe for all three eg q collections. When 50 perce nt or mo re of the eggs remained viable howeve r , the subsequent data from those trays was included in the evaluations of time to hatch and complete yolk absor ption. Incubation timing a nd survival: Comp u tations of the average temperature (f or each regime) to various develop- mental stages allowed fo r standardized comparisons between study tempera - tures. The average temperature to complete yolk absorption showed the co lder to warmer trend between the mai n stem, Sl, 52 and 4°C Constant temperature regimes (Table 2). Table 2. Average water temperature during incubatio n of chum eggs and alevins to 50 percent hatch and complete yolk absorptio n in four temperature regimes. (Data were pooled from replicates and egg collections.) Temperature regime Main stem Sl 52 Constant 4°C Average water temperature (°C) 50 Percent hatch Complete yolk absorption 1.7 2.2 3 .6 2.9 4.6 3.9 4.0 4.0 The day s required from egg fe rtili zatio n to 50 percent hatch and comp lete yolk absorption (Appendix 1) is inversely proportional to increases in tem- perature between the four temperature regimes (Fig. 5). €ggs required abo ut 61 more days to reach 50 percent hatch an d alevins required 70 more days to complete yo lk absorptio n in the main-stem temperatures, as compa red to t he Constant 4°C or 52 temperatures. z • 2 ,_ ~ .. - •• :i -"' ... 2 0 cz: ... ., >-... <C a ... .. .. TaoiPERT\IRE REG~ES .. Figure 5. Days from fertilization to so~ hatch (cross- hatched bars} and complete yolk abso rp tion (open bars) for chum salmon at fou r different tempe rature re - gimes which simulated the Susitna mai n stem (MS), Slough 8A (S2), an inter - mediary (SI6 , and 4°C Constant (4 C). Data we re pooled from three fertil- ization dates i n Septembe r and from study repl icates} 0 • • .. i ~ • c ~ .. c c • .. 2 .. .. Q .. .. c 4 ~ 2 ~ Q 0 c CHU"' S"L..MOM -------... •• .. If' TI!W .. ei'IA TUI'II IIEOIWI!S Figure 6. Accumulated temperature units (°C) to reach SO% hatch (cros s-hatc hed bars) and complete yolk absorp- tio n (open bars) fo r chum salmon at four di fferent temperatu r e regimes •~thich simulated the Sus itna ma in stem (MS), Slough 8A (52), an intermediary (S l), an d 4°C Constant (4°). (Data were pooled from th r e e fertilization dates in September and from study rep 1 i cates . ) I n contrast , the accumulatio n of TUs is directly proportional to the in - creases in temperatu re between the fou r study regimes fo r egg hatching and complete yolk ab s orption (Fig. 6). Eggs required about 187 less TUs to 50 percent hatch and alevins required 239 less TUs to complete yo l k a bsorptio n in the main -stem temperatures as compared to the Constant 4°C or 52 tempera- tures (A ppendix 1}. 13 ~7 Thu s if chum salmon were spawning from early to mid-September n l emperature ~ regim es s im i lar to those in this study, hatching would t ake place from mid- Decemb er to mid -March, and complete yo lk abso rption from ea rly Ap ril to late June (Tab le 3). Ta ble 3. Oates for hatching and complete yolk absorption for chum eggs and alevins incuba ted at four tempe rature regimes based on spawning dates of September 3 and 15. Temperature regime Spawning date 50 Percent hatch Comp lete yo lk abso r ptio n Main stem 03 Feb r uary 11 June 16 Main stem 15 March 16 June 24 Sl 03 Dec emb er 29 May 08 Sl 15 January 22 May 22 S2 03 Decembe r 17 April 06 S2 15 Decemb er 29 Apri 1 17 Constant 4°C 03 December 31 Apri 1 07 Constant 4°C 15 Ja nuary 09 Ap ril 14 Chum egg a nd alev ir surviva l was greater than 90 perce nt (Appendix 1) for all four temperature regim es (Fig. 7). Ab nor mal ities noted i n the main-stem I I • . ' temperature regime included cu r ved spines, deformed body pa rts, and "h ea d-. (. , f irst" hatchi ng. --J p • , ~~~I ''",>,G..,. "7 l -'r:'"' .,_ Leng ths and weights: Weight measurements were taken through 50 percent hatch a nd for some alevins with complete yolk sac abso rption. But the weighing pr ocess was tim e con- sumi ng and the r es ults (from blot drying) had li tt le interpretive value betwee n temperature regimes, so the measu r eme nts were discontinued. The mea n weig ht for all chum alevins at 50 perc en t hatch was 0 .20 g ± 0.01 g (95 percent CI). No weight analysis was performed between egg collec t ions . • • Figu r e 7. • •• ~ ., .. <I :!!: .. c ::> • .. z • 0 c • .. •• .... ..._ _________ _ ... .. .. .. Tt:WI'I!IU.TUIII iti!QI WI!S DRAFT Percent su r vival fo r chum salmo n eggs and Qievins reared to com - plete yolk absorption at fou r different t em perature reg imes which simulated the Susitna ma i n stem (MS), Slough SA (52), an intermed- diary (Sl), and 4°C Consta nt (4°). Cross-hatched area represents percent of abnormalities amo ng survivors . (Data were poo l ed from three fertilization dates in Sep temb er and fro m study replicates .) A one -way analysis of va r iance (AN OVA) for alevin lengths at 50 percent hatch for all temperature regimes and egg collecti ons (minus the deleted trays me ntioned earlier) revealed differences bet~een the gro ups (P<O.Ol). With some exceptions , temperature regi mes with colder average temp eratures res ul ted i n sma l ler a l evi n lengths at 50 percent hatch (Fig. 8). A Du nca n multiple compariso n test (P=O.O l ) resulted in groupings which separated the alevin lengths of the warmest temperatu r e regimes f r om the coldest (Tab l e 4). The difference in length from the smal l er to larger alevins was 2.5 mm (1 1 pe r cent). Length dn a l ysis (one way ANOVA) of chum alevins at comp lete yo lk absorptio n a l so revealed a s igni fica nt difference betwee n the gr oups of tempe rature regimes and egg collections (P<O .Ol). Mean lengths a nd 95 percent confidence 15 interva l s of these groups are plotted in Fig. 9. Th e difference i n lenqth bet·,.e~n the smallest to largest group was 1.9 mm (5 percent). i .! z .. " z • .. z ; • .. c z c • :1 .... .... .... ...• , ... + 1 I CHUM SAL..'140N 50'\'o HATCH i .! z ··~· :; .... z • ..I z ; • .. c ••.• z c • 2 CHUM SAL.MON COMPL£T£ YOLK ABSORPT I O N t l +tit t ........ ____ ""'-" __ .... _.._.._. .•• ttl •••••• . ...... , ... . wa at s2 •· ... " 32 •• Figures 8 and 9. T I!,.I'IIU lUll It III!QIWI8 TlfWI'I!IIA TUIIIt 111!01Wit8 Mean lengths of chum salmo n alevins at 50% hatch and at total yolk absorption (horizontal lines) from three ferti- lizatio n dates (!=September 3; 2~September 9; 3=Septemb er 15) within each of four different temperature regimes. The temperature regimes simulated the Susitna main stem (MS), Slough 8A (S2), an intermediary (Sl), an d 4°C Constant (4°). (Data were pooled from study replicates. Vertical li~es represent 95% confidence inter vals.) Table 4. Mean lengths of chum alevins at SO percent hatch which are brack- eted into statistically similar groups (P=0 .01 ) and their corres- po nd ing temperature regime and egg collection. (Data were pooled within replicates.) Egg co 11 ecti on date Average Mean TemQerature reg im e {Se2tember} tem2era ture ( oc) length ~mm} Main stern 15 1.5 21.7 Main stem 9 1.7 22.5 11 Main stern 3 2.0 22 .9 S2 15 4 .6 22.9 S1 15 3.4 23.1 Cons ta nt 4°C 9 4 .0 23.1 S1 9 3.6 23 .2 Sl 3 3.9 23.5 S2 9 4.7 23.7 Co ns ta nt 4°C 15 4 .0 23.7 Constant 4°C 3 4.0 24.1 S2 3 4.7 24.2 16 D ~J\ ~7 RJ-i\.s .. Growth and tempe r ature unit accumulation: Alevin growth (total length) was plotted versus accumulated temperature units (°C) for all four temperatu re regimes of the first egg collection (Figs. 10 and 11) and for three tempe rature regimes of the third egg collection (Fig. 12). Comparative differences (TUs and days to SO percent ha tch and CYA) wi th in a single egg co lle~t io n were me nt ioned previously. Va ri ations in growt h curves are noted her e . A greater deflection in the slope of the main- stem growt h curves as compared to Sl and S2 is observed in Figs. 10 and 12 . The greatest chang e i n slope for the main-stem growth curves appears at about • 380 TUs for the first egg collection and about 300 TU s for the third eg g collection. For both ma in-stem temperature regimes this represents the increased water temperatures greater than l°C wh ich occurred du ring th~ first week in May. The cons tant 4°C water temperature regime is presented in a sepa rate figure because of an almost complete overlap of data points with S2. Similarly, the growth curves for Sl, S2 and ConstaPt 4°C are al ~0st identical when the first a ."ld third egg collections are compa re\1 . Differences between the mai n-stem g r owth curves for the first and third egg collections are related to the colder average water temperatures experiP.nced by eggs from the third egg collection . Development r d~es: Developmen t rates were comp uted (to 50 percent hatch and com plete yolk ab-• 17 sorptio n) and plotted from results of this study and available literature on chum incubation (Figs. 13 and 14). A regression analysis was performed on t he data for each incubation stage. In each regression equation R2 was greater than 0 .92 (Table 5). Thus chum development rates are predictable for know n temperature regimes. . l: ... ~ z Ill .J z -> Ill 2 .J < CHUM SALMON • t ,.,.·~NGTH -~H / " . 3 ,. l80 .we 510 575 840 706 770 638 AC CUM ULAT~D TEMPZRATURE UNITS ( 8 C) Figure 10. Alevin growth (total length) from 50~ hatch to comp lete yo lk absorption for chum salmon incubated at three different tem- perature r e gimes . The regimes simulated th e Susitna main stem (MS), Slough 8A (52}, and an intermediary (Sl). (Data are based on a fertilizatio n date of September 3. Data from replicates were po0led.} • . ~ ·. Figure 11. 45 40 ~ ~ :t 35 1- 0 z Ill .J z 30 -> Ill .J < ~5 20 18 DR. A ·r-~ . t .... 4 ' • ~ . .. .. CHUM SAL.MON J..I. . .L·f···l , .. c I •• · •• • I I I CONSTANT 1_.:.···,·· I 1 ••• I .! .... :····· I ••• I !. ........ , {~~~N~TH ~AN~E . . I 5 3 e fJ 2 1 1 1 • ·MEAN / a o 8 8 0 0 ACCUMULATED TEMPERATURE UNITS (•c) Alevin growt h (total l ength) from 50% hatch to complete yolk absorption for chum salmon incubated at Constant 4"C. (Data are based on a fertilization date of September 3.) Table 5. Regression analysis of development rates for chum alevins to 50 percent hatch and complete yolk absorption from data in Figs. 13 and 14. Incubation stage 50 p~rce nt hatch Complete yol~ absorption 0.959 0.927 Slope 0.63 1.51 Y i ntercept -1.4 -2.9 19 CHUI-4 SA L MON :r :r 3a :t 1- ~ z "' ... )0 z > "' ... c 2!1 J I !I )110 us s 10 57S 840 l OS 170 ~& ACCUMULATED I~MPERATURE UNITS ( •c) Figure 12. Alevin growth (total length) from 50% hatch to complete yolk ab- sorption for chum salmon incubated at three different temperature regimes . The regimes simulated the Susitna main stem (MS}, Slough 8A (52), and an intermediary (S l ). (Data are based on a fertili- zation date of September 15. Data from replicates were pooled .) Figure 13. ~ 12 1.1.1 ~ -< 0:: 1.1.1 ~ UJ --< ~ u z d > < •• CHUM 50% HATCH I •• • • ,.. • ' I I • .. i # + 12 ' , I ' "M4 1 s R!!:PORT (51!:111: TABLE AI'ID APPENDIX I) RAYMOI'IO ( I 9 8 t I BAK..U.LA ! t 910 I CRAY'IJILL ET AL • ( 1979) 18 <I CHUM OEV~_QFMENT RAiE<1000/0AYS) Development rates to 50% hatch for chum salmon incubated at various temperatures (°C). The reciprocal of the days to 50% hatch was multiplied by 1000. 4 • Figure 14 . u 0 l.&J a:: ::I -< a:: l.&J a.. :1: 1.4.1 -:z: 0 -< CD ::I ~ d > < •• 2 20 CHUM COMPLETE YOLK A8SORPT10N • I •• ~TH I S REPORT {SEE TAB~ 4 AND APPE ND I X I) 0 RA YllfOND ( I 9 8 I ) + GRAYBI~~ ETA ~. {197 9 ) 8 CHUM OEVELOP~ENT R~E<1000 /0AY5) • Development rates to complete yolk abso r ption fo r chum salmo n incubated at various temperatures (°C ). The reciprocal of the days to com plete yolk abso r ptio n was multiplied by 1000. Sockeye Salmo n Six of the 24 incu~ator trays co nta ining sockeye sal mo n we r e eliminated from ana lysis of gr owth and su r viva l due to uncontro ll ed lethal stresses. These r e presented the ther:na l regimes Sl (seco nd egg co llection), S2 (second egg collection), S2 replicate (a ll three egg co ll ections) and the Consta nt 4°C replicate (second eg g co llectio n). As with ou r analysis fo r ch um salmo n, when 50 percent or more of the eggs remained viable, the subseq uent data from those trays were included in the evaluation of tim e to ha tch and comp lete yo l k absorptio n. Incubation timing and surviva l : 21 Average tempe rature (for each regime) was calculated (Ap . n 1) to mak e comparisons between temperature regim es and timing to 50 percent hatch and complete yoik absorption (Table 6). Ta bl~ 6 . Average water temperature during incubatio n of sockeye eggs and alevins to 50 percent hatch and complete yolk absorptio n in four tem perature regimes. (Data were pooled from replicates and egg collections . Temperature regime Main stem Sl S2 Constant 4•c A t ( ·c) verage water tempera ure SO Percent hatch Comp lete yolk absorption 1.5 3.3 4.2 4.0 2 .1 3 .0 3.9 4.0 Soc keye e ggs required abo ut 71 more days to reach 50 percent hatch and alevins r eq u i red 56 more days to complete yolk absorption 1n the main-stem tempe r ature regimes as compared to the Constant 4°C or S2 temperatures (Fig. 15). In compa r ison, eggs r equired about 291 less TUs {Appendix 1) to 50 percent hatch and alevins required 301 less TUs to co mplete yolk absorption in the main-stem temperatures than the Constant 4•c or S2 temperatures (Fig. 16). Thus, if sockeye salmon were to spawn from early to mid -S eptembe r in tempera- ture regimes similar to those in this study, hatching would take place from late January to early May and comp le ~e yolk absorption would t &ke place from mi d Apri l to late June (Tab le 7}. 22 Figure 15. ll 2 .. c ~ ~ .. 11: • ... :1 0 c . • ,. c 0 SOCK E YE SALMON ... •• .. .. Days from ferti l ization to SO% hatch (cross - hatched bars) and com- plete yolk absorption {ope n bars) for sockeye salmon at fou r different temperature r·egimes which simulated the Susitna main stem (MS), Slough 8A (S2), a n intermediary (Sl), and 4•c Constant (4°). (Data were pooled from three fertilization dates i n September a nd from study rep l icates .) 0 • SOCKEYE SALMO N • .. -i 2 • -c :t .. c ••• c .. .. :1 -• .. Q • -.. • c J -:t :1 :t ~ ~ -c -... •• .. , T!NI'I!I'IA TU III I! IIIIOI WI!S Figure 16. Accum ulated temperature units (•c) to reach 50% hatch (cross -hatched bars) and complete yolk absorption (ope n bars) for sockeye salmo n at four different tempera- ture regimes which simu - lated the Susitna main stem (MS), Slough 8A (S2), an intermediary (S1), and 4°C Consta nt (4°). (Data were pooled from three fertilizat i on dates in September and from study replicates.) Table 7. Oates for ha t ching and complete yolk absorption for sockeye eggs and alevins incubated at four temperatu r e regi me s based on spawning dates of September 3 and 15 . Temperature regime Spawning date 50 Percent hatch Complete yolk abso r ption Mai n stem 03 March 29 June 14 Mai n stem 15 May 05 June 25 Sl 03 February 11 May 26 S1 15 March OS June 09 S2 03 Janua ry 23 Ap ril 14 S2 15 Feb ruary 10 April 12 Constant 4•c 03 February 01 Apri l 12 Constant 4"C 15 February 10 Apri l 26 r--• • • - Sockeye egg and than 90 percent (Appendix 1) for all temp erature regimes (Fig. 17). Abnormalities noted in main -stem and Constant 4•c temperatures included curved spines, twining, double hea ds and tails, and head-first hatching • Figure 17. ••• SOCKEYE SA L~.tON ~ c ., .. ~ ~ c ::. • .. z .. • • .. c .. ~ .... L-_.;...._.;.... ____ .... ... •• .. .. Percent survival for sockeye salmon eggs and alevins reared to complete yolk absorption at four different temperature regimes which simulated the Susitna main stem (MS), Slough 8A (S2), an intermediary (Sl), and 4°C Constant (4•). Cross -hatched area represe nts percent of abnormalities amo ng survivors. (Data were pooled from three fertilization dates in September and from study rep l icates .) lengths and weights: Analysis of so ckeye weights at 50 percent hatch offered little information. The mean weight of sockeye at 50 pe rcent hatch \las 0.11 g. No variat i on was observed bet•11een temperature regimes or egg co llections when evaluated by a one-way (ANOVA) and a Duncan multiple comparison test (P=O.Ol). • =·' • -; ....... ..) .""'':, ~ ·-·~ ..... U :'i ·, · ..... · ..,..~ "'Mk .. ~ .. ._n ~u ,.. A one-way (ANOVA) for alevin lengths at 50 percent hatch for all temperature regimes and egg collections (minus the deleted trays mentioned earlier) revealed differences between the groups (P<O.Ol). Similar to the chum lengths at 50 pe r cent hatch, a trend was observed wherein colder ave ra ge temperatures resulted i n smaller alevin lengths (Fig. 18). A Duncan ~ultiple comparison test (P=O.Ol) resulted in the groupi ng of alevin lengths in an order which separated the coldest and warmest temperature regimes (Table 8). The difference in length from the smalle r to larger alevins 'lidS 1.8 mm (8 percent). Table 8. Mean lengths of sockeye alevins at 50 pe rcent hatch which are bracketed into similar groups (P=0.01) a nd their co rresponding temperature re9ime and egg collection. (Data we re pooled with- ; n rep 1 i cates. ) Egg collection date Averag e Mean Temperature regime (Sep tember) tempe ra ture ( oc) length (mm ) Main stem 09 1.5 21 .8] Main s t em 03 1.7 22.0 Main stem 15 1.3 22 .5 Sl 15 3.1 22.7 Constant 4°C 09 4.0 22. Sl 09 3.3 22.9 52 03 4.3 23.1 Co ns ta nt 4°C 15 4.1 23 .2 Constant 4°C 03 4.0 23 .2 S1 03 3 .4 23.3 52 15 4.2 23.6 Length analysis (one-way ANOVA) of sock eye alevins at com plete yo lk absorp- tion also revealed a significa nt difference between the groups of temperature regimes and egg collections (P<O.Ol). No trend was observed betwee n mean lengths of alevins wi thin the four reg im es (Fig . 19). The differe nc e in • • • • • • • • • 25 length betwee n the smallest a nd largest group was 1 .7 mm (5.7 perce nt ). (If those two groups are eliminated th e range differe nce is 0.6 mm.) SOCK:EY£ SALMON SOCKEYE SALMO N 50.,. H ATCH COMPLETE YOLK ABSORPTION .... ,,,, .l t i ++ I ++ i ! + ! :z: , ... % ' ..• .. + :; t-+++ ., + z z + • H .. .. f-+ .. z z ; ; .. .. .. .. .... c , ... c 1 z J... z I c c .. • 2 I :II Jt.O II. I • I I 0 I I ' • I ' I • ' I I ' I J ' -. ' 1 • Wt:'· " S2 .. ... S1 sz . . tiWI't!IIA TUllE REQIWII Tf.WI't!IIATUIIE !lt!OIWES Figures 18 and 19 . Mean lengths of sockeye salmon alevins at 50% hatch an d at total yolk absorption (horizo nta l lines) from three ferti l ization dates (!=September 3; 2=Septembe r 9; 3= September 15) within each of fou r different temperature regimes. The temperature regimes simu l ated the Sus i tna maim stem (MS), Slo ugh 8A (52), a n intermediary (Sl), a nd 4•c Consta nt (4•). (Data were pool ed from study repli- cates. Ve r tical li nes represe nt 95% confidence intervals .) Growth and temperature unit accum ul atio n : Alevi n gro wth (tota l length) was plotted versus accumulated tempe rature uni ts (•c) for all fo ur temperature regimes of the first egg collection (Figs. 20 an d 21) and fo r three temperatu re regimes of the third egg collectio n (Fig. 22). The greatest chang e in growth curve s l ope for the alevins of the first egg collection occur r e~ in the mai n-stem temperature regime at abo ut 38 0 (TUs ). This coincides with the increase in i ncubation temperatu .e ~bov e t•c. 26 Th e largest change i n gr owth curve slope for the alevins of the t hird egg c ol lection occurred in t he main -stem temperature reg im e at about 530 (TUs). This coincides with a n increase of wate r t em peratu r e above 1o•c. The eggs of this regime had not reached 50 percent ha t ch until early May, when water tem peratures were already higher than 1•c. • S OCKEYE S ALMON 51 ~ ~ :z: ... Cl z 11.1 .J ,, z > 11.1 .J < • UIH GTH RANGE -MEAN l21 '''·' ••o su.s HI '''·' roo a2.s u s '''·' a eo ACCUMULATE D T EMPE~ATUR E UNITS ( °C) Fig ure 20 . Alevin growth (to ta l length) from SO~ hatch to complete yolk absorption for sockeye salmon incubated at three different temp era ture regimes . The reg im es simulated the Susitna main stem (MS), Slough 8A (S 2), an d an inte rmed ia ry (S l}. (D ata a r e based on a ferti l izat io n date of Septembe r 3 . Data from repl icates we re po oled.) c •••• Figure 21 . ::E :!: :t 1- ~ z Ill .J z -> Ill .J < 3 5 3 0 2 5 2 0 J 27 SOCKEYE SALMON 0 I I II CONSTANT 4 c II I •• ··y 1 I ~.i.J..rin 1 . 1 !.-~·····1 rl I I.~J ··jl 'I '· .~···j ,,, ••• I q /' t • W.:NCTH RANCI!'; •MEAN ,I' ~'" e5o 725 aoo &75 1i150 ACCUMULA T ~O TEMPERATURE UNITS ( °C) Alevin growth (total le ngth J :·0m 50% hatch to complete yolk absorption for sockeye salmon in~ ~a ted at Constant 4°C. (Data are based on a fertilization ua te of September 3.) The Constant 4°C water temperature re gim e is presented separately (F ig . 21) becaus e of an almost complete ove r la p of data points with S2. Similarly, th e gr owth c urves for Sl, S2 and Consta nt 4°C are almost identical whe n the first and third eg g collections are compared . • % ... I!) z Ill .J z > 2 Ill .J < 300 380 _s •110 us SilO ~~ .. ~~~ ... t ' ...., ·. ~,. ... Lt .·' !:C.t.' • ;,j ,. ,,. • I ~~ L.E.NGTH RANG!!: / ·MEAN ~ a:zo sa a ACCl.JMULA TEO TEMPERA n.JRE UNITS ( °C ) Figure 22. Alevin growth (total length} from 50% hatch to complete yolk absorption for sockeye salmon incubated at three different temperature regimes. The regimes simulated the Susitna main stem (MS}, Slough SA (S2}, and an intermediary (Sl). (Data are based on a fertilization date of Septemb er 15. Data from replicates were pooled .) Development rates: Development rates were computed (to 50 percent hatch and complete yolk absorption) and plotted from the results of this study and from data avail· able in the literature (Figs. 23 and 24}. A regression analysis was per· formed o n the data for each incubation stage. The R2 value fo r each re· gression line was greater than 0.97 (Table 9}. • • • ''• .. - ~n ;\, :-1 f ~ ,Y ~ • U.-·,l-\.2 u 0 12 w a:: SOCKEY E :;) ..... < g 50% HAT CH a:: w Cl.. % w • ..... 0 • ... • < * TH I S REPORT (SEE FIG. a CD ,. :;) u • ANO AP PENDIX ' ) z 3 f)VELSON ( 1980) c..:) •• t OLSEN I I 968) > • < # II!:VLEVA I t9 s 1 ) • I 4 8 12 liS DEVE LOPMENT RATE <1000/0AYS) Figure 23. Development rates to 50% hatch fo r sockeye salmon incubated at va r ious temperatures (°C). The reciprocal of the days to 50% hatch was multiplied by 1000. -u 0 12 w 0:: :::::> ..... < 0:: w Cl.. % w ..... % 0 IS -..... < CD :::::> <.J % c..:) > < •• SOCKEY E COMPLETE YOLK ABSORPTION •• • • 3 OEVELOP~ENT RATE<I000/0AYS) II • *THIS REPORT (SEE FIG. 8 AND APPENDIX I) t O L SEN ( t 9 6 8 ) 12 Figure 24. Developme nt rates to comp le t e yolk abso rption for sockeye salmon incubated at va rious temperatu res (°C). The reciprocal of the . days to complete yolk absorption was mu l tiplied by 1000. 30 Table 9. !?~{ :, :--:; Regression ana 1 ys is of deve 1 opment ra t~s ;or. soc k~;e eggs to 50 percent hatch and alevins t~omplete yolk absorption from data in Figs. 23 and 24. Incubation Stage 50 Perce nt hatch Complete yolk absorptio n 0.977 0 .973 Slope 0.78 1.07 Y intercept -1.6 -1.3 Thu~. sockeye development rates are highly predictable within know n tempera - ture r anges . • Discussio n Field ob servations indicate that chum a nd sockeye fry achiev e complet e yo lk absorption in Susitna s 1 oughs by early Apri l, and mid to late Apri l respec- tively (ADF&G 1983). These findings agree well with our results (Tables 3 and 7) for the S2 (Slough 8A simulation) and Constant 4°C temperature re- gimes . Our study shows that Susitna River chum salmon achieve complete yolk sac absorption within 218 days of fertilization (Fig. 5) when incubated at an average 3.9°C (S2)(Table 2) which simulated temperatures in Slough 8A. Incu- bation at a constant temperature of 4°C produced essentially the same resu l t. Incubation at our two coldest regimes (S1 and MS), however, lengthened the amount of time required for complete yolk absorptio n by about one and two mo nths, respectively . These find ings were simila r for Susitna sockeye sa l mon which were incubated simultaneous ly within the same four ~e mpe rature regimes 31 ••• "'=' •• ., (Fig. 15 and Table 6). It has been suggested that some salmonids can r~gulate deve l opment rates under altered temperature regimes so that yolk absorption is achieved at. the most optimal time during spring (Dong 1981). The similarities in incubatio n time (TUs and days) between 52 and 4oc (constant) for chum and sockeye to reach complete yo l k absorptio n can be explained by the similar average incu - bating temperature to yolk absorption within each regime (Figs. 3 and 4 and Tables 2 and 6). The slower development rates which occurred within our coldest regimes (MS and Sl) are also proportional to the number of TUs ac- cumulated . Thus, we find no evidence that chum and s ock eye from Slough 11 have the ability to regulate their development rate s to accomodate tempera - ture alterations from 2.1° to 4°C . It is possible that the average post-project temperature regime wi l l be out - side the range we evaluated i n this study (2.1 to 4°C). As our data are directly applicable to a ra nge at or below 4°C, it would be useful if pre- dictive model could estimate incubation timing for chum and sockeye beyond this ra nge. This informatio n is presented below. First however, we will suggest two possib l e temperature scenarios which may result from reservoir construction so that subsequent data presentations may be pl aced into per- spective . First, a slight increase in the annua l average water t~mperature of the Susitna main stem may elevate winter ground water temperatures in the sloughs. Such an increase (for example, 4.5°C average) could result in an earlier emergence as compared to our warmest temperature regime (4°C 32 .DRAfT constant). Secondly, fluctuations in winter discharge in the main stem could result in increased channel ice formation. Increased ice staging of the river may divert main stem flows and inundate sloughs with 0°C water. If completion of the incubation process were delayed by one to two mo nths (as occurred in our main stem and Sl temperature simulations), it may have a significant effect on the smoltification of the chum. The sme lting process, which is critical to the successful ocean adaptation of salmon, can dysfunction is it occurs ''out of phase" to the historical smolt timing as when temperature has de- creased or increa sed alevin developm~nt (Folmar et al. 1982). The effect on sockeye sa l mon is less clear as they wii1 be rearing for another o ne to two years outside of the slough habitat before their Qutmigration as s molts. Our results with Susitna River salmon indicate increase ~ in mo rtalities a nd ~ abnormalities begin when average incubation temperatures to hatch are less then 3.4°C for chum and sockeye, or when initial incubation temperatures are z equal to 4°C for sockeye (Figs. 7 and 17, Tables 4 and 8). Our coldest temperature regime was represented by the egg collection of 1S September incubating in the main-stem simulation. Chum and sockeye eggs were incuba- ting for 31 days with about 1S6 TUs (S°C average) before water temperatures were decreased to 1.4°C in this reg i me. Sockeye eggs are noted for being vulnerable to temperature stress before closure of the blastopore, which occurs at about 28 days and 140 TUs (S°C average)(Velsen 1980; Barns 1967; Combs 196S). Thus, our coldest temperature regime did not subject the egg s to thermal stresses before they could successfully adjust. J • • • • • 33 7"'. " " -: -~ I I Baily and Evans (1971) repo r ted an increase i n morta;·it;~~ -:~r p;nk Jmon (~ gorbuscha) when initial incubation was below 4.5°C , and complete mortal i- ty Jccu r red when initial incubation was below 2.0°C. Studies with coho sal mon (Q..:_ kisutch) have also noted 100 percent mortality when eggs •11ere initially incubated i n temperatu r es below 1.0°C (Do ng 1981). This type of co ld water stress (early in the incubation process) doe s not appea r to be a likely post-project eve nt in th e Susitna. The i nundat ion of sl ou ghs later in the winter howev er, could quickly reduce incubati ng tempera- tures by 2 to 3°C. While this wo uld definitely alte r the timing of develop- me nt processes, it appears that salmonid eggs are not lethal ly stressed by such water temperature changes when they are past closure of their bl asto - pore. The mea n length of chum a nd sockeye alevins was significa ntly sma ller at ~ hatching when i ncubated in colder average t emp erature reg im es (Tables 4 and 8). These results have also bee n noted for variatio ns of othe r incubating co nditions such as volume of eggs per inc ubato r, dissolved oxyge n levels, substrate type and water flow {Kapuscinski and Lanna n 1983; Fuss a nd Johnson 1982; Peter ~on et al. 1977; Garside 1959 ; Hayes et a l . 1953). Hatching can result ear l ier depending upo n incubating conditions (Garside 1959), and Hayes et a l. (1953) suggested col d wate r temperatures wou ld be expected to promote ea rly hatching (relative to development stag e). Addit i onally, the mea n alevin l ength s at c~mp l ete yolk absorption (Figs. 9 a nd 19) did not revea l the differences betwee n temper a ture regi mes f ou nd a t hatching. The refo r e, we did not obs e rve a less efficient development proce ·s i n cold wate r at hatching , but rather ,the alevins in c older water temperatures had hatched · • • • • 34 at an ea r lie r stage . Don g (19 81) also concluded that the metabolic efficien - cy i n coho alevi ns was compa rable or hi gher at 1.3°C as opp osed to 4.0 or 6.l°C. Tempe ratures higher tha n 6.l °C res ul ted in smaller a l evi n lengths at com plete yolk abso rpt i on (Do ng 1981) . ~hi le the metabo lic efficiency appea rs si mila r i n ou r study temperatures , th e ~rowth r ate di d not . A clear increase in gr owt h rates resulted from i n- creasi ng water temperatures above 1.0°C i n the main-stem tempe r atu r e regime s fo r both species (Figs. 10 , 12, an d 20 ). Temperature s greater tha n 1 .0 t o 4.0°C resulted in s imila r slopes when gr owth in length was plotted ov er TU s . A literature review an d results from this study have prod uced a usefu l pre- dictive tool for estimating the numbe r of days needed from fe r tilizatio n t o hatch ing or c om plete yolk ab s orpt ion for chum and sockeye salmo n i n the Sus itna River System . The developme nt rates ca n b~ calculated fo r eithe r specie s give n a n ave ~age incubation t emperatur e and the infor matio n i n Tab l es 5 and 9 . ~ If fo,r examp le, a model of post-proj ect wate r temperatu re predicts th at a slough with i ncubating salmo n eggs will have a n average temperature o f 4.5°C (Septembe r to May) the numbe r o f day s requ i red to comp l ete yo lk a bso rpt i on fo r chum could be ca l culate d as fo ll ows: y = mx + b, whe re y =average wate r temperat ure (°C ) m =slope of chum yo l k abso rp tion regression line (Tab l e 5) x = chum developmen t rate {to be calcu l ated ) b = y intercept (Tabl e 5). 35 injp §\G:7 U~'\~~ ~ Solving the equation for x calculates a developme nt rate for chum (at 4.5°C) of 4 .9. Dividing 1000 by 4.9 results in a prediction of 204 days from ferti- lization to complete yolk absorption . That would r e sult in a decrease in the I chum incubation time o f about none days from our warmest temperature regime (4°C constant}. • Al tering the therma l regi mes and discharges of a majo r river will have ma ny effects beyond those observed on sa lmon eggs a nd alevi ns . The results from this study indicate incubation timing i s an important factor which will be af fected by alt ered water t empe ratures. But all sal mon life stages will be directly affected by changes in tempe rature regimes which act in concert with other fac to rs as physiological regulators 'm etabolism and gr owth} and be - havioral sti muli (migration and ove rwintering strategies}. Reso urce planners will be a ble to use data from this report and plan manageme nt, mitigatio n or en hanc em ent objectiv e s to the exte nt that post -project t empe r atu re regimes ca n be predicted . Acknowledgement s Da na Schmidt (ADF&G } su ggested the need for this study and was instrume ntal ~n project desig n and review . Special thanks are extended to John McDonnell who helpe d construct and implement the incubat ion facilities . His ma ny late ni ghts a nd weekends at the lab insured the successfu l com pletion of this study. Keith Bayha a nd his staff (Ecological Services Division, US~AS) insured the ti mely comme nc em ent of thi s study. • • • • • 36 Gary Wedemeyer (USFWS} an d Rich ard Wilmot (USPA S} pro vided review o f study prog ress and suggestions for statistical analyses. We tha nk Tom Tre nt (ADF&G, Susitna Hydro , Aquatic Divisio n } a nd his staff fo r their cooperation in providing field temperature measurements. Woody Trihey provided logisti - cal suppo r t fo r a Novembe r field trip to Slough 11 . Seve ral (USFWS} peop le provided logistical suppor t. Amo ng those we thank Ma r tha Ronaldson (typing}, Tim Whit l ey (technicia n), Brad Grei n (graphics) and Jo Gorde r (co ntracting}. We appreciate th e assistance of NM FS emp l oyees such as Sid Korn , Adam Moles and Stanley Rice, all o f whom provided helpful a dvice . Lite r ature Cited Alaska Department of Fish and Game. 1983 . Susitna Hydro Aquatic Studies Phase II Final Data Repo r t Vol. 3 , Resident and Juvenile Anadr omous Fish Studies , 1982 . Alderdice, D.F., F.P.J. Ve l se n. 1978. Relatio n between temperatu re a nd incubatio n time for eggs of chinook salmo n (Onco rhynchus tshawytscha}. J . Fish. Res . Board Ca n . 35:69-75. Bailey, J .E. and O.R . Evans . 1971. The low-temperatur e threshold fo r pi nk salmo n eggs in relation to a proposed hydroe l ectric installatio n. Fis h. Bu 11 . Vo 1 . 69 ( 3) . 37 Bakkala, R.G. 1970. Synopsis of biological data on the chum s almon, Oncor- hynchus keta (Walbaum). FAO Fisheries Synopsis No . 41. U.S . Fish Wild . Serv. Circ. 315. Barns, R.A . 1967. A review of the literature on the effects of changes in temperature regime or developing sockeye salmon eggs and alevins. J . Fish . Res. Board Can., MS, 949:14-22. Com bs, B.D . 1965. Effect of temperature on the development of salmon egg s. Prog. Fish. Cult. 27(3) . • Dong. J.N. 1981. Thermal t ol e r a nce a nd r ate of development of coho sal mon embryos . M.S. thesis, Univ. Washington. Folmar, L.C., W.W. Oickhoff , C.V.W. Mahnken , and F.W. Waknitz. 1982. Stunting a nd parr-reversion during smoltification of coho salmon (Onco r- hynchus kisutc h). Aquaculture 28:91 -104 . Fuss, H.J. and C. Johnson. 198 2 . Quality of chum salmon fry imp roved by incubation over artificia l substrates . Prog. Fish. Cult. (44)4. Ga rside, E.T. 1959. Some effects of oxygen in relation to temperature or the development of lake trout emb ryos. Can . J. Zool . Vol. 37. Gr a ybill, J.P ., R.L. Burgner , J.C. Gislaso n, P.E. Huffma n, K.H. Wyman , R.G. Gibbons , K.W . Kruko , Q.J. Stober, T.W. Fagnan, A.P. Stayman , an d D.M • . Eggers. 1979. Assess ment of the reservoir-related effects of the Skag it • • , . • • 38 project on downstream fishery resources of the Skagit River, Washingto n . FRI-VW-7905. Univ. of Washington, Seattle. Hayes, F.R., D. Pelluet , and E. Gorham . 1953 . Some effects of temperature o n the emb ryo ni c developm2nt of the salmon (Salmo sala r ). Can. J. of Zoo 1. Vo 1. 31. Ievleva, M.Ya. 1951. Morphology and ra te of emb r yo nic developmen t of Fac i- fic sal mon. Jzvestiya Tikhookeansl<.ogo nauchno Vol . 34, pp. 123 -130 . Kapuscinski, A.R.D ., and J .E. Lanna n. 1983. On density of chum salmon (Oncorh yn chus keta) eggs in shallow matri x substrate incubators. Can . J. Fish. Aquat. Sci. 40:185-191. Leitritz, E. and R.C. Lewis . 1980 . Trout a nd sal mon culture (hat c hery methods ). Calif. Fish Su ll . No . 164. California Dept . of Fish and Gam e . Nei, N.H., C.H. Hu ll , J.G. Jenkins, K. Steinbrenner, O.H. Be rt . 1 975. Sta- tistical package for the social sciences. ~-1cG ra w-Hill Book Co. Olse n , J.C . 1968. Physical environment and egg de ve l opme nt in a ma inl a nd be ach atea and an is l and beach area of Iliamna Lake. In: Further Stu- dies of Al aska Sockeye Salmon. Univ. \~ash. Pub. in Fisheries. New Series Vol. III, Robert L. Burgner (ed.). Peterson, R.H., H.C.E . Spinne y, an d A. Sre edharan. 1977. Development of / Atlantic salmon (Salmo salar) eggs and avev ins under varied temperature •• t • • 39 reg imes. J . Fish. Res . Boa rd Ca n . 34:31 -43. .. ,.c., • . ... Raymond, J.A . 1981 . Incubation of fa ll chum salmo n (Oncorhynchus keta) at Cl ear Air Force Station, Alaska. Alaska Dept. of Fish an d Game Info. Leaflet No. 189 . • Soka l , R.R . a nd F.S. Rohl'. 1969. Bi ometry. State Univ . of New York at Stony Brook . W.H. Freema n and Co., San Francisco. Trihey, E.W. 1982. 1982 Winter t em per a ture study. Acres Ame ri can Inc. Guffalo , Ne w York . Velse n, F.P.J. 1980. Embryo nic development in eggs of sockeye salmo n (Oncorhynchus nerka). Canadian Special Publicatio n of Fis heries an d Aquatic Sciences 49 . I I I I 1 :11 Appendix 1. Ex perimental design and associated data for chum (trays 1-3) and sockey e (trays 5-7) sal mon to achieve SOX hatch and complete yolk absorp t1 on at four d1fferent temperature reg1mes. Regimes (each was rep li cated) s 1mulated the mai n-stem Susitna River , Slough SA (S2). an 1n termedia ry regime (S l), and a Consta nt 4•c . (Eg gs for th1s study were fert111z ed on three occas1ons during September , 1902.) . ' I • l ncub•t or Hlln Ste111 S1 S2 Con~ltnl 4"C Trty I z 3 5 6 1 I z 3 5 6 1 I 2 3 5 6 7 I z l 5 6 ----t---,.__ --~ -t------ s: lUI I 320 293 262 349 321 299 457 446 H4 552 550 Sl~ 491 son 478 606 607 613 476 473 471 6111 liiD •• '-' s 0 .... 1-1----1-------· ·-"'~Oays since 161 172 182 211 211 235 117 122 131 161 I ll 1/2 105 112 106 14 0 14 2 14 7 119 11 7 116 152 152 (ertt llutlon ... IU' s l 614 635 638 594 SO l 616 133 746 121 793 6 10 6 10 660 -642 06 ) -69!1 665 66 3 67 1 669 IllS -c f---~~ Oays s I nee Z87 166 284 185 10 1 102 246 153 150 26 4 269 260 ZIO . 216 ZZ5 . ZlZ 21 6 213 214 222 216 .., ~J£rtll t ulJoo ------· ----------------~ :; l'ercenl 94 91 92 95 90 91 96 98 91 98 -99 --97 99 -99 97 98 96 9/ 9fl -"'surv i va l 0 c t--· -I------··· -· -------··--·· --· -- .-·- I - 595 - 146 911!1 - 221 - 97 --15 "' l'e r cent 0 0 .9 1.8 <0.1 ·0.1 0.1 0 0 0.2 0 -<0.1 --0 .1 0 -0 0 0.1 0 0 u 0 .3 ~booaldll ties lncu b•lor Halo Ste111 Repllc•le S1 ~·epl l c•le S2 nerl t c•te Con~ hnl 4"C Rerllcale - Tr•y I 2 3 5 6 1 1 2 3 5 6 7 1 z l 5 6 7 1 2 l 5 6 7 ,_ -- c Til's I 320 292 266 344 320 294 457 444 us 546 5J4 521 493 406 470 620 616 622 -41) 472 602 6 0~ 60/ •• It o u --r----f------"' "'Days s I nee 162 173 162 204 215 230 lOS 14 7 14 9 11 7 II/ lSI 1511 ·~ll c fcrll llu.liQn 11 8 122 128 161 164 160 105 104 145 ----f-. --- --... 1U's 1 594 604 606 564 564 648 731 130 708 791 17 2 792 649 65 4 8H 676 938 919 -856 643 6119 90fo 910 o ~ llays since ---1-------------------- »::; rcrll l lu llon 26 5 26 3 261 264 201 265 z.\9 252 249 266 262 266 21 3 216 213 222 24 1 2311 -212 206 223 224 22 4 :l e-r cmiii ___ --r--------·---,_ --·----------------· ---·· -r--------·- ~ ~ survlv11 l 96 95 94 96 96 98 98 90 99 98 99 90 97 96 93 ------911 9~ 911 o o--------------· -· -------- ------·---··· ... -·-·-·. --E "'l'ercenl 0.3 1.5 2.2 0 .2 0 0 8 a lmormal lll c~ 0 0 0 0 :0.1 0 0 0 0 ----- - 0 ( n.1 1 l ll's-accumula ted temrerilure units ("C). -Ouhes In d icate thot da t• were lost due to unconlrolled stresses .