FISHERY BULLETIN: VOL. 7L NO. 3 



Figure \. — Oceanic distribution and relative abundance of steelhead trout in winter (January-April). Catch and effort 

 data from gill net, longline, and purse seine sets by research vessels of Canada (1961-67), Japan (1955-57), and the United 

 States (1953, 1955-67). 



of the North Pacific Ocean in May and June 

 (Figure 2). They occurred in limited numbers 

 along the Aleutian Islands to about long. 180° 

 and the Okhotsk Sea off southwest Kamchatka. 

 The movement resulted in catches in the area 

 of winter concentration being reduced from 2.4 

 to 1.5 fish per set. The greatest spring concentra- 

 tion of steelhead trout (0.72 per set) appeared 

 to be off the coasts of southeast Alaska, British 

 Columbia, Washington, and Oregon, west to 

 about long. 165°W, north of lat. 44°N. In the 

 central North Pacific Ocean, the Aleutian 

 Islands area (west of long. 165 °W) and the 

 Okhotsk Sea catches averaged only 0.02 steel- 

 head trout per set. None were caught in the 

 Bering Sea during spring in 418 sets. 



The most extensive movement of steelhead 

 trout northward occurs in the summer (Figure 

 3). Their oceanic range at this time extends 

 westward across the North Pacific Ocean from 

 the coasts of the United States and British 

 Columbia to the Kuril Islands in Asia north of 

 lat. 44°-46°N and may extend northward to 



about lat. 52°N in the Okhotsk Sea, lat. 56°N in 

 the Bering Sea, and lat. 59°N in the Gulf of 

 Alaska. The bulk of the fish, however, were 

 found north of lat. 44°N; the catch averaged 

 0.86 steelhead trout per set. As a result of the 

 summer shift, the steelhead trout catch in the 

 area where they were concentrated in the winter 

 declined 89% from 2.4 fish per set to 0.27 fish 

 per set. 



West of long. 175 °W to near southeast 

 Kamchatka and south to lat. 44°N, the catch of 

 steelhead trout averaged 0.16 per set in the 

 summer. In the Okhotsk Sea, the Japanese 

 reported three steelhead trout caught in 349 

 sets for a catch per set of 0.009 fish. Some move- 

 ment of steelhead trout through the Aleutian 

 Island passes in the summer was indicated by 

 two catches of one steelhead trout each in the 

 Bering Sea. 



The fall distribution and abundance of steel- 

 head trout is described from a total of only 48 

 sets made by Canadian and United States ves- 

 sels. Those sets were scattered over a vast ocean 



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