Immature fish also appeared to move north- 

 ward in early June. They were throughout 

 the Ridge Area although catches were small. 

 It is known that they inhabit the Ridge Area 

 abundantly in the summer. 



Catches gave no evidence of a major migra- 

 tion of maturing Bristol Bay fish south of the 

 central Aleutian Islands in spring 1968. Sup- 

 port for this conclusion was based on: (1) 

 the low relative abundance of sockeye salmon 

 along long. 175° W., which shows that Bristol 

 Bay fish had not reached this area by late May, 

 and (2) the appearance in early June of mi- 

 grating Bristol Bay fish in the western Gulf 

 of Alaska — too far east to allow them to mi- 

 grate westward past the central Aleutian Is- 



lands to western passes and still reach Bristol 

 Bay in the normal time period (early July). 

 Migrations of salmon may vary with the flow 

 of the Alaskan Stream; we will continue to 

 investigate this hypothesis in future studies. 

 Japanese research vessels also fished in the 

 North Pacific Ocean in April and May 1967 — 

 see figure 10 for comparison of the 1967 and 

 1968 catches. Sockeye salmon appeared to be 

 more abundant in 1967 than in 1968. Cruises 

 were generally different in the 2 years, but 

 the distribution of sockeye salmon appeared 

 to be similar for those areas fished in 1967 and 

 1968; most of the fish were between lat. 45° N. 

 and 50° N. The southern limit of distribution 

 seemed to be farther north in 1968 than in 1967, 



Figure 10. — Relative abundance of sockeye salmon (immature and maturing) in April 



and May 1967 and 1968. 



12 



