FISHING RESULTS 

 John N. Cobb 



Fifty gill net stations were occupied by 

 the John N. Cobb from June 25 to September 13 

 in the offshore waters extending from off north- 

 ern Vancouver Island northward to southeastern 

 Alaska and across the Gulf of Alaska as far west 

 as Unalaska Island (fig. 13). Salmon were 

 caught in the gill nets at each station, all five 

 species being taken in a number of the sets . 



Total gill -net catch of salmon for the 50 

 sets was 2,484, an average of 49 salmon per set. 

 Individual catches ranged from 1 to 168 salmon. 

 The catch included 1,248 chums, 639 pinks, 367 

 reds, 211 silvers, and 19 kings. Salmon-troll- 

 ing gear fished in the vicinity of five gill -net 

 stations caught 18 silvers, 3 pinks, and 1 king. 

 In addition to salmon, the gill nets caught 55 

 steelhead trout and various numbers of pomfret, 

 jack mackerel, dogfish, mackerel shark, and a 

 few ragfish and squid. Tables 1 and la present 

 the complete fishing log of the John N ■ Cobb, in- 

 cluding dates, positions, catches by species, 

 and other pertinent data. 



Several stations in the Gulf of Alaska 

 were fished a second time after an interval of 

 about 2 months to compare catch results over a 

 period of time . To com pare effectiveness of 

 the gill nets in day and night fishing, 3 sets 

 were made in the daytime . The daytime sets 

 each caught salmon, but the catch in each in- 

 stance was less than the catches made in the 

 same place at night. 



Catch by species and mesh size 



Chum salmon were most abundant in the 

 gill -net catch of the John N. Cobb , comprising 

 slightly over 50 percent of the total (table 2) . 

 Pinks were next most abundant, at 25.7 percent. 

 Kings were least numerous, forming less than 

 1 percent of the catch. Species composition 

 varied with dates and areas fished, as can be 

 seen in the fishing log and in table 5. At no time 

 were any jumpers or other surface signs of 

 salmon seen in the offshore waters, and all gill - 

 net sets were made "blind" . 



Table 2 also shows the catch by species 

 for each of the four sizes of gill nets. The 4-1/2- 



inch mesh was most effective, catching 3.31 

 salmon per shackle. Next most effective mesh 

 size was 5-1/4-inch, with an average catch of 

 2.45 per shackle. The 3-1/4-inch nets were 

 least effective, 1.2 salmon per shackle, while 

 the 6 -inch nets were slightly higher at 1.58 sal- 

 mon per shackle. Average catch for the 1,018 

 fifty-fathom shackles fished was 2.44 salmon 

 per shackle. 



Each of the net sizes was selective to a 

 degree in sizes of fish caught (fig. 16). This 

 selection also affected the catch of some species 

 for each mesh size. For instance, more reds 

 and chums were taken in the smaller 3-1/4-inch 

 nets than any of the other species, because small, 

 immature individuals were more abundant in 

 these two species than the others. Chums oc- 

 curred most often in the 4- 1/2 -inch and 5-1/4- 

 inch mesh. No small, immature pinks were 

 caught. The number of kings taken was too small 

 for significant comparison. 



Depth of Salmon 



A record was kept of the depth in the net 

 at which the salmon were enmeshed (table 3). 

 From these observations it is apparent that the 

 salmon spend much of their time in the offshore 

 waters very near the surface. 



The nets were constructed to fish from 

 the surface to a depth of approximately 20 feet. 

 For purposes of recording depth of the salmon, 

 the nets were arbitrarily divided into three parts, 

 and the position of each salmon caught was re- 

 corded as in the "upper", "middle", or "lower" 

 third of the net. In recording these data the 

 observer merely made a quick judgment of the 

 position of each fish as the net came near the 

 vessel, as it approached the roller, or as the fish 

 were being removed. Thus, there is some chance 

 for error on those fish which were near the border 

 lines of "upper", "middle", or "lower". 



Table 3 shows that over half (53 percent) 

 of the salmon caught by the John N. Cobb were 

 recorded in the upper one -third of the nets, or 

 within 7 feet of the surface. In the lower one- 

 third there was a higher percentage of Kings and 

 reds than of the other 3 species, and conversely, 

 kings and reds had lower percentages than the 

 others in the upper part of the nets. The apparent 



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