Mortensen et al : Growth of Oncorhynchus gorbuscha in relation to marine water temperature, secondary production, and survival 323 



were most abundant in late April and 

 early May; 70-809f of the catch occurred 

 between 5 May and 1 June. Most pink 

 salmon left the nearshore area by late 

 May. Salmon catch offshore tended to 

 increase coincidentally with the decline in 

 catch near shore; offshore catches peaked 

 between May and mid-June, depending 

 on the year (Fig. 2). Most tagged juve- 

 niles were recaptured near shore; only 

 11 and 2 fish were recaptured offshore in 

 1987 and 1988, respectively ( no fish were 

 recaptui'ed in 1989, and no offshore sam- 

 pling occurred in 1986). By mid- July of 

 each year, juveniles were not present in 

 nearshore or offshore catches. 



Estuarine residence time (based on 

 recaptures of tagged fish) generally de- 

 creased with progressive release dates. The 

 exception was 1988, when residence time 

 was similar between all release groups. 

 Mean residence time ranged from a high 

 of 30 d for the early release in 1986 and 

 1987 to about 7 d for the late release in 

 1989. The mean residence was also signifi- 

 cantly longer in the first two weeks of 1986 

 and 1987 than in 1988 and 1989 (Table 1). 

 Mean residence times did not differ signif- 

 icantly by release week between 1986 and 

 1987 or between 1988 and 1989, but were 

 significantly different between 1987 and 

 1988. Based on recaptured tagged fish, 

 maximum residence times in Auke Bay 

 ranged from 19 d for juveniles from the 3 

 May release in 1988 to 72 d for the juve- 

 niles fi-om the 13 April release in 1987 (Table 1). 



Nearshore catches consisted primarily of juvenile 

 pink and chum salmon (Fig. 3). In even years, pink 

 salmon juveniles were more abundant than chum 

 salmon juveniles; pink salmon juveniles made up 

 SS'/r and 65'7f of the catch in 1986 and 1988, versus 

 169^ and 17*7^ for chum salmon juveniles. In con- 

 trast, the ratios of pink and chum salmon in odd 

 years were nearly equal (52-43'7r, 1987, and 52-44*7^, 

 1989). Coho (O. kisutch) and sockeye (O. nerka) 

 salmon smolts and juvenile and adult Dolly Varden 

 (Salvelinus malma) were also captured each year. 

 Other nonsalmonid fishes captured included juve- 

 nile Pacific herring {Clupea pallasi) sculpins (Cotti- 

 dae,) juvenile flatfish (Pleuronectidae), and juvenile 

 walleye pollock (Theragra chalcogramma). Juvenile 

 Pacific herring made up a significant proportion of 

 the nearshore catch (14%) only in 1988. 



Offshore catch composition for 1987 through 1989 

 consisted primarily of Pacific herring and capelin 



(Mallotus villosus). Pink salmon were the most abun- 

 dant salmonid captured in offshore sampling. In 1987 

 and 1988, pink salmon made up 109^^ and 13% of 

 the offshore catch respectively. Juvenile herring and 

 capelin accounted for 76% and 74% of the offshore 

 catch in 1987 and 1988, respectively. In 1989, pink 

 salmon accounted for only 0.1% of the offshore catches, 

 whereas juvenile Pacific herring were abundant and 

 accounted for 97% of the total fish numbers. Fewer 

 chum salmon juveniles and sockeye, coho, and chinook 

 (O. tshawytscha) smolts were caught offshore than 

 inshore. Other fish caught included juvenile and adult 

 walleye pollock, sculpins, Pacific sandfish {Tridiodon 

 trichodon) and starry flounder (Platichthys stellatus). 



Predators 



Coho salmon smolts, medium (fork length 15>.r>30 

 mm) and large (fork length >30 cm) Dolly Varden, 

 and three sculpin species (great sculpin, Myoxoceph- 



