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Fishery Bulletin 98(2) 



alus polyacanthocephaluf!, Pacific staghorn sculpin, 

 Leptocottus armatus, and buffalo sculpin, Enophrys 

 bison) were capture(i in beach seines and surface 

 trawls along with juvenile salmon. We also observed 

 these fish striking at schools of juvenile pink salmon 

 in nearshore areas. Examination of the stomachs of 

 a few of these predators showed that pink salmon 

 juveniles were indeed a dietary item. The abundance 

 of potential predators captured in beach seines and 

 tow net trawls was similar for all study years. Tem- 

 porally, the number of predators initially increased 

 slowly in April, then rose sharply in late April, 

 peaked by late May, and declined sharply in June 

 (Fig. 4). The period of rapid increase and decline each 

 year was due primarily to the pulse of coho salmon 

 smolts entering Auke Bay in May and leaving in 

 June. Dolly Varden and sculpin numbers increased 



more gradually in the spring and remained steady 

 throughout late spring and early summer. 



Water temperature and prey 



Water temperature generally increased rapidly 

 during April, May, and early June (Wing and Pella, 

 1998). Temperatures ranged from 3" to 5°C in late 

 March to 10-14°C in June (Fig. 5). Temperature in 

 1986 and 1987 remamed below S^fC for at least a 

 week longer in April compared with temperature in 

 1988 and 1989. 



Prey organisms of the juvenile salmon consisted 

 primarily of zooplankton and littoral harpacticoid 

 copepods. The seasonal dynamics of the biomass of 

 zooplankton prey in the upper 40 m and upper 5 m 

 of the Auke Bay water column have been discussed 



