FISHERY BULLETIN: VOL. 71, NO. 3 



Table 2.- 



Year 



-Catch of steelhead trout and catch per gill net and longline set by research vessels of the National 



Marine Fisheries Service, 1953, 1955-67. 



Date 



Number 



of 

 vessels 



No. of 

 sets 



Gill net catches 



No. of 



steelhead 



trout 



Catch/set 



Longline catches 



No. of 

 sets 



No. of 



steelhead 



trout 



Cotch/set 



1,282 



,341 



1.05 



19 

 5 



18 

 



0.95 



24 



0.75 



negligible catch. Longline fishing was repeated 

 on a larger scale in 1964 and again in 1965. 

 The results are summarized in Table 2. In the 

 2 yr, 24 sets were made and 18 steelhead trout 

 caught. They were taken in two sets in 1964 in 

 the Gulf of Alaska east of long. 143°W, where 

 steelhead trout frequently occur in consider- 

 able abundance. The catch per set averaged 

 0.75 fish in the 2 yr. The ratio of steelhead to 

 salmon in longline catches averaged 1:30 

 (Table 1), or 3V2 times more steelhead trout 

 (in relation to salmon) than indicated by gill 

 net catches in all years. 



Fisheries Research Institute 



FRI has assigned two to four vessels to high- 

 seas fisheries research annually during 1956- 

 67. Their fishing areas have been primarily in 

 the eastern North Pacific Ocean, Gulf of Alaska, 

 and the Aleutian Islands area. In some years, 

 fishing was extended to the western North 

 Pacific, Bering Sea, and Bristol Bay. The 

 operations usually were limited to the spring 

 and summer seasons, beginning in April or 

 May and ending in August or September. In 

 1959, fishing began in late March and ended in 

 mid-October; in 1967, it ended in late October. 



The main objective of the research was to 

 study migrations of salmon and steelhead trout 

 by tagging captured live fish. Purse seines were 

 used each year for that purpose; the longlines 



also were used in 1963-66. The catch and effort 

 data for both gears are given in Tables 1 and 3. 



Steelhead trout catches by purse seines were 

 substantially smaller than by either longlines 

 or gill nets. The largest average catch of steel- 

 head trout in any year was only 0.21 fish per 

 set (1958). None were caught in either 1959 

 or 1960 in 292 sets. The average purse seine 

 catch in 12 yr of operation was 0.07 steelhead 

 trout per set. By comparison, gill net catches by 

 NMFS average 0.82 per set in 1959, 0.70 in 

 1960, and 1.05 in 14 yr of fishing. The ratio of 

 steelhead trout to salmon in the purse seine 

 catches averaged 1:1,012 in 12 yr of fishing, or 

 about one-tenth of the steelhead trout (in rela- 

 tion to salmon) indicated by gill net catch of 

 NMFS (Table 1). 



Longline catches of steelhead trout in 4 yr of 

 fishing averaged 0.81 fish per set and exceeded 

 catches per set by purse seines in all years. The 

 average catch per set was comparable to that of 

 gill nets but exceeded that of gill nets in some 

 years. In 1964, when NMFS failed to catch a 

 steelhead trout in 13 sets in the Aleutian Islands 

 area, FRI caught 49 in 87 longline sets in the 

 Gulf of Alaska for a catch per set of 0.56. The 

 ratio of steelhead trout to salmon was 1:68 in 

 longline catches, about IV2 times more steel- 

 head trout (in relation to salmon) than the 

 ratio (1:105) indicated by gill net catches of 

 NMFS. 



In comparing purse seine and gill net catches, 



792 



