84 



Fishery Bulletin 92(1). 1994 



40 



30 



Outside waters 

 Outer coast inlets 

 Inside waters 



Pink 



Coho 



Chum Sockeye 



Salmon species 



Figure 3 



Catch per unit of effort (CPUE) and frequency of occurrence of 

 juvenile salmonids (pink, Oncorhynchus gorbuscha; chum, O. keta; 

 sockeye, O. nerka; coho, O. kisutch; in outside waters (77 sets), 

 outer coast inlets (45 sets), and inside waters ( 109 sets) in South- 

 east Alaska in 1983 and 1984 combined. 



Pink and chum salmon FO was lowest nearshore, 

 then increased and stabilized mid-distance offshore, 

 around 37 km (Fig. 4C). Pink salmon were caught 

 in all sets beyond 37 km and had the highest FO of 

 all species; sockeye salmon FO remained constant 

 2-74 km offshore. Coho salmon FO was the highest 

 nearshore (2 km) of all species, then the FO stabi- 

 lized at 37 km and beyond (Fig. 4C). 



By sampling period Abundance of juvenile salmon 

 in Southeast Alaska increased from July (CPUE=11) 

 to August (CPUE=58) 1984 for all species. Summed 

 over all habitats, pink, chum, sockeye, and coho 

 salmon had higher FO's and abundance in August 

 than in July. In outside waters, CPUE of each spe- 

 cies increased two to seven times from July to Au- 

 gust 1984, with juvenile pink salmon showing the 



largest increase (Fig. 5). In inside wa- 

 ters, CPUE of pink and chum salmon 

 increased 10 and 5 times respectively 

 from July to August, whereas CPUE's 

 of sockeye and coho salmon remained 

 constant (Fig. 5). For all four species, 

 FO increased in outside waters but de- 

 creased in inside waters from July to 

 August 1984 (Fig. 5). The low number 

 of sets (four) made in outer coast inlets 

 of Southeast Alaska in August 1984 

 precluded seasonal comparisons of 

 CPUE or FO for this habitat. 



Size 



Juvenile salmon were larger in outside 

 waters than in inside waters. Thirteen 

 matched pairs of size samples could be 

 compared under the hypothesis that 

 size did not vary between outside and 

 inside waters; the fish were larger in 

 the outside water in all comparisons 

 (Table 4, x 2 =133.66, df=26, P<0.005) 

 and the null hypothesis was rejected. 

 Juvenile salmon in outside waters 

 were larger farther seaward. Of the 

 eight possible matched pairs of samples 

 compared under the hypothesis that 

 size was not different between outside 

 waters >37 km offshore and <37 km 

 offshore, the juvenile salmon were 

 larger >37 km seaward in all compari- 

 sons (Table 4, x 2 = 67.44, df=16, 

 P<0.005). 



Juvenile salmon in northern waters 



were larger than those in southern 



waters. The fish were larger in the 



northward locations than southward locations in 18 



of 23 possible paired size comparisons (Table 4, 



X 2 =214.76, df=46, P<0.005). 



Juvenile salmon were larger in August than in 

 July. Of the matched size samples compared under 

 the hypothesis that size was not different between 

 August and July of 1984, fish in August were larger 

 than in July in 10 of 12 comparisons (Table 4, 

 X 2 =145.36, df=24, P<0.005). 



The sizes between the different species of juvenile 

 Pacific salmon differed significantly (P<0.05) (Table 

 5). Coho salmon juveniles were significantly larger 

 than other species in each sampling period; mean 

 length of coho salmon was always at least 40% 

 greater than in other species, whereas pink, chum, 

 and sockeye salmon were within 9% of each other. 

 Juvenile sockeye salmon were significantly larger 



