to September in the eastern Bering Sea and 



Bristol Bay is as marked as the absence of 



small reds, lending further evidence that 



eastern Bering Sea is not a feeding area 

 for immature salmon. 



Pink salmon . — The greater part of a 

 small catch of pink salmon was taken in the 

 Gulf of Alaska and the general vicinity of 

 Kodiak Island in late July and early August; 

 more than half of the total by the Celtic 

 (fig. 14). Small numbers were taken in mid- 

 June by the Mitkof in the central Aleutians 

 cind by the Tordenskjold in eastern Bering 

 Sea. 



Silver and king salmon . — As shown in 

 tables 1-6 (pages 6-11), silver and king 

 salmon were taken in small numbers and were 

 widely distributed. Six juvenile silvers, 

 26 to 34 centimeters in length, were taken 

 near Kodiak Island. Most of the silvers 

 captured were in the 50- to 70-centimeter 

 length range. 



King salmon ranged from 27 to 90 centi- 

 meters in length with no clearly dominant 

 size evident in the small numbers captured. 

 The Mitkof operating in the westernmost 

 areas made the largest catch, 33. A few 

 small kings, 27 to 38 centimeters in length, 

 were taken by the Mitkof and the Torden - 

 skjold , all of them in Bering Sea. 



VERTICAL DISTRIBUTION OF 

 SALMON CATCH 



It has been observed that most gill- 

 netted salmon are taken near the surface. 

 The Tordenskjold , with a predominance of 

 maturing red salmon in the catch, captured 

 1,366 or 55 percent in the upper 1/3, 699 

 or 28 percent in the middle 1/3, and 408 or 

 17 percent in the lower 1/3 of nets which 

 are approximately 20 feet in depth. This 

 vertical distribution is in conformity with 

 the observations of Barnaby in 1939 (Barna- 

 by, 1952) who reported that with a net some 

 90 feet in depth at least 95 percent of the 

 catch was taken within 30 feet of the sur- 

 face and "many of the fish were caught in 

 the top fathom". His catches were made at 

 the entrance to Bristol Bay on a line from 

 Cape Seniavin to Cape Newenham, and con- 

 sisted of maturing red and chum salmon. 

 Barnaby's sets were made during the day 

 while the Tordenskjold 's were made at night. 



Total season's catch of the Mitkof in 

 1956 shows 47 percent (523) in the top, 40 

 percent (447) in the middle, and 13 percent 

 (144) in the bottom third of the nets; the 

 Paragon , 42 percent (586), 44 percent (614), 

 and 14 percent (195); and the Celtic , 51 

 percent (1,045), 26 percent (523), and 23 

 percent (462). Cursory inspection of the 

 record sheets indicates that catches tend 

 to be greater near the surface in clam or 

 moderate seas, increase in the lower por- 

 tion of the nets during periods of rougher 

 we at he r . 



An evaluation of vertical distribution 

 of salmon on the basis of this evidence 

 might, however, be misleading. While errors 

 of observation and record should be minor 

 and compensatory, there is little doubt that 

 a bias does exist in the nets themselves 

 resulting from the fact that fish can swim 

 under but not over them. This tends to in- 

 crease the efficiency of the upper portion 

 of the net in relation to the deeper por- 

 tion. 



The evidence does suggest, however, a 

 surface tendency on the part of the salmon 

 which may be most pronounced in migrating 

 mature fish and may be influenced in some 

 degree by the condition of the sea. Fuku- 

 hara (1953) notes that it is the experience 

 of the extensive Japanese high seas gillnet 

 fishery that 85 to 90 percent of the salmon 

 are taken in the upper 10 feet of net, and 

 Powell and Peterson (1957) observe that 53 

 percent of the salmon taken by the John N. 

 Cobb in 1955 were gilled in the upper third 

 of the nets. 



SURFACE WATER TEMPERATURES 

 AND SALMON CATCH 



Surface water temperatures in the 

 region in which salmon were captured ranged 

 from 32.9° to 58.2° F. Variations relating 

 to both area and season contribute to this 

 temperature range of 25.3°. Lower tempera- 

 tures were encountered in eastern Bering 

 Sea and warmer temperatures near the south- 

 ern boundary of salmon distribution in the 

 North Pacific. No juvenile red or chum 

 salmon were captured in temperatures below 

 40° F. and, in Bering Sea, the largest 

 catches of mature red salmon were associated 

 with water temperatures of 42° and 44° F. 

 In warmer waters south of the Aleutian 



18 



