SUTHERLAND: DISTRIBUTION OF STEELHEAD TROUT 



steelhead trout to vsalmon was 1 steelhead trout 

 per 30 salmon in longline catches by NMFS 

 vessels fishing primarily in the eastern North 

 Pacific Ocean. The lowest ratio was 1 steelhead 

 trout per 49,632 salmon in longline catches by 

 Japanese vessels fishing primarily in the 

 western North Pacific Ocean. The catch by all 

 vessels in all years averaged 1 steelhead trout 

 per 1,023 salmon. Fishing effort and catches in 

 coastal waters of British Columbia, Washing- 

 ton, and Oregon were omitted, since the data 

 add little to the subject of oceanic distribution 

 of steelhead trout. Sets of experimental gear 

 were also omitted unless the effort was repeated 

 2 or more years and sufficient numbers of fish 

 were caught to justify consideration. 



United States Research Vessels 



National Marine Fisheries Service 



In 1953 and annually since 1955, NMFS 

 assigned one to five vessels to fisheries research 

 in the North Pacific Ocean and Aleutian Islands 

 area; in some years, NMFS vessels were also in 

 the Gulf of Alaska and the Bering Sea. No 

 research was conducted in 1954. The fishing 

 area was from about lat. 41 °N northward to lat. 

 60 °N and from the coast of the United States 

 and Canada westward to about long. 170°E. 

 The fishing period was limited to spring and 

 summer in 1953, 1955-62, and 1966. In 1963- 

 65 and 1967, fishing extended from early 

 winter (January or February) to early or late 

 summer. 



In the 14 yr of operation the vessels fished 

 33,319 shackles of gill net in 1,282 sets and 

 caught 1,341 steelhead trout for an average 

 catch of 1.05 steelhead trout per set (Table 2). 

 The catch per set ranged from a high of 2.3 

 in 1963 to a low of none in 1964. The latter 

 figure possibly resulted from a limited effort of 

 only 13 sets, all west of long. 170°W. The 

 relative abundance of steelhead trout in rela- 

 tion to salmon (as measured by the ratio of 

 steelhead trout to salmon in the gill net catches) 

 averaged 1: 105 over the 14 yr (Table 1). 



NMFS first experimented with longlines in 

 1953. The 1953 catch data were not included 

 in this report because of limited fishing and 



791 



