FISHERY BULLETIN: VOL. 72, NO. 2 



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 12 

 CPUE 



12 

 CPUE 



Figure 12. — Distribution and abundance of age .1 sockeye salmon in July 1967, 1968, 

 1969 as shown by catches of Japanese research vessels. 



and 



Table 3. — Freshwater age composition of age .1 sockeye salmon 

 from samples along long. 158°W, 167°W, and 176°W in summer 

 1966. 



Further evidence that a considerable proportion 

 of the Bristol Bay immature sockeye salmon 

 remain in the northeastern Pacific Ocean through 

 the summer is indicated by catch data from 

 research vessels fishing simultaneously along 

 various longitudes in July and August (Bak- 

 kala, 1971). These data (Figures 10 and 11) 

 showing peaks in relative abundance followed by 

 a decline in abundance in two or three areas at 

 similar time periods indicated that the major 

 proportion of immatures from the eastern areas 

 did not migrate westward and move through the 

 area south of the central Aleutian Islands at a 

 later time period. 



Royce et al. (1968) suggested that many age 



.1 sockeye salmon from Bristol Bay migrate north- 

 ward into the Bering Sea in late summer. The 

 fact that some Bristol Bay sockeye occupy waters 

 of the western Bering Sea has been established 

 by the recapture of 5 sockeye in Bristol Bay 

 tagged as immatures in the Bering Sea west of 

 180". Recent catch data indicate that the abun- 

 dance of Bristol Bay immatures in the Bering 

 Sea varies depending upon the abundance of the 

 stock and perhaps on other factors. Machidori 

 (1970)' reported on catches of age .1 sockeye 

 salmon in the Bering Sea during research cruises 

 in 1967, 1968, and 1969. His data are shown in 

 Figures 12, 13, and 14 as converted from tans 

 (one tan of gill net is 50 m long) to CPUE in 

 equivalent shackles of gear. Although fishing 

 effort was not equal in all areas in July, 

 August, and September, the data suggested lack of 

 substantial numbers of salmon in the Bering Sea 

 east of long. 175''E in July, but show large 

 catches in August indicating a movement of 



''Machidori, S. 1970. On summer distribution of immature 

 sockeye salmon in the northwestern North Pacific and its 

 adjacent waters. [In Japanese] Fish. Agency Jap., Tokyo 

 (Int. North Pac. Fish. Comm. Doc. 1311), 59 p. (Transl., 15 p.) 



600 



