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Fishery Bulletin 98(2) 



release to recovery to provide the growth rate (the 

 slope of the regression line) for each release group. 

 Using g we then calculated the relative growth, h, 

 as the percentage of body weight per day (%bwd) for 

 each fish and for each group was calculated from the 

 formula 



h =(exps- 1) 100. 



Tagged juveniles that were recaptured within a week 

 of the mean release date from the Auke Creek weir 

 were not used in gi'owth rate calculations. It was 

 assumed that after a week the fish had acclimated 

 to the marine environment and were recovered from 

 prerelease tagging stress. In addition to the above 

 calculations, the weights of tagged and untagged 

 juveniles at successive capture dates were logarith- 

 mically transformed and regressed against days from 

 the mean release day to the day of capture. 



To determine how water temperature and food 

 abundance relate to growth in the estuary, individ- 

 ual growth rates of tagged fish were correlated with 

 average surface water temperature and prey bio- 

 mass over the period between release and recapture. 

 The average daily biomass of prey organisms was 

 calculated for three habitats: the upper 5-m of the 

 water column, the upper 40-m of the water column, 

 and the littoral zone (harpacticoid copepods only). 

 Correlation analysis and stepwise regression (Zar, 

 1974) were employed to determine significant cor- 

 relations and provide partial correlation coefficients 

 for each of the above parameters. 



To test the possibility that estuarine growth of 

 juvenile pink salmon could be limited by prey avail- 

 ability, the residual (difference) between expected 

 and actual growth of individual juvenile pink salmon 

 at given water temperatures was calculated and plot- 

 ted against average water temperature. Expected 

 maximum growth rates for given temperatures were 

 obtained from (Mortensen and Savikko, 1993). 



Growth of the tagged juvenile pink salmon was 

 also computed for two periods or stanzas. Each year, 

 the early period was that before and including 5 

 May, and the late period was that after 5 May. These 

 dates were chosen because of the distinct change in 

 size of juveniles between the two periods and the 

 distribution of tag recoveries. Each year a dramatic 

 increase in length was noted in the tagged fish at 

 the beginning of May. Growth for each tagged group 

 within a year was calculated for the early period; this 

 rate was then used to estimate the initial weight for 

 each tag group for computation of growth in the late 

 period. Differences in growth between periods and 

 years were tested by using analysis of covariance 

 (ANCOVA) and the Newman-Keuls multiple com- 



parison or Dunnet's tests (Zar, 1974). Significance 

 levels were set at a = 0.05. 



Survival offish from each release group for each emi- 

 grant year, 1986-1989 (brood years 1985-1988) was 

 determined from the number of adult salmon return- 

 ing to the Auke Creek weir. Each pink salmon adult 

 passing through the weir was examined for a coded 

 ware tag (cwt) on the adipose fin. Clipped fish were 

 killed and their heads removed. Fish with adipose fins 

 were returned to the creek to spawn. Coded-wire tags 

 were removed from heads of the clipped fish later at 

 the laboratory. Fish that showed a clip mark but were 

 missing cwts were assigned to an emigration group 

 that was based upon the proportion of all tag codes 

 recovered each return week. Therefore, the return 

 of each emigration group was the number of known 

 tagged fish plus an expansion for clipped fish that had 

 lost their tags. The total return of pink salmon adults 

 to Auke Creek was the product of weir recoveries and 

 a fisheiy correction factor. The fishery correction factor 

 for each brood year was determined as 



1/il-h ), 



where h - harvest rate determined as the propor- 

 tion of the total return that is caught 

 in the commercial fishery according to 

 estimates by Alaska Department of Fish 

 and Game (ADF&G) commercial fisher- 

 ies management personnel. 



Fishery correction factors obtained from the commer- 

 cial fisheries branch of ADF&G for the 1985-1988 

 broods at Auke Creek were 1.45, 1.03, 1.53, and 1.43, 

 respectively.'' Growth and survival of the individual 

 release groups within each year were standardized 

 as a proportion of the highest rates observed. The 

 proportional growth rate for each release group was 

 regressed against proportional survival to deter- 

 mine the degree to which growth rate was a pre- 

 dictor of intra-annual survival. Survival rates were 

 regressed against gi'owth rates to determine the rela- 

 tion between gi'owth and interannual survival. 



Results 



Catch and residency times 



Juvenile pink salmon use Auke Bay as a nursery area 

 throughout the spring and early summer and reside 

 nearshorefrom late March until mid-June. Pink salmon 



3 Ingledue, D. 1987-90. Alaska Department of Fish and Game, 

 Division of Commercial Fisheries, Southeast Regional Office. 

 802 Third Street, Douglas, Alaska 99609. Personal commun. 



