PACIFIC SALMON 



75 



Of the two fishes, the red salmon, when 

 there is a choice, will choose the fork of a 

 river which drains a lake. The other, the 

 king salmon, does not choose between the 

 two forks but will move up either one or 

 the other. 



We will now consider accurate observa- 

 tions made on these two species of salmon 

 and see if the characteristic behaviors can 

 in any way be correlated with their migra- 

 tory movements and distribution. 



The most interesting as well as the most 

 instructive tagging experiments (Fig. 1) 

 are those reported by Gilbert (1924) and 

 Gilbert and Rich (1927a). Red salmon 

 were tagged in Ikatan Bay (entrance to 

 Isanotski Strait), Morzhovoi Bay (just east 

 of Ikatan Bay) and Unga Island of the 

 Shumagin Islands group (some 125 miles 

 east of Ikatan Ba^O- All three tagging 

 localities are on the south side of the 

 Alaskan Peninsula. Not a single red 

 salmon tagged in either of the bays was 

 captured on the south side of the peninsula 

 east of Morzhovoi Bay. Those that were 

 not captured in one or the other of the two 

 bays were captured north of the peninsula 

 and to the east along the margin of and in 

 rivers emptying into Bristol Bay. A few 

 were captured at Port Moller, about one- 

 third down toward Bristol Bay on the 

 north side of the peninsula. Red salmon 

 tagged at Port Moller were not captured 

 outside its waters. Results were different 

 with the Unga Island experiments. The 

 majority of the recaptures were along the 

 route to Isanotski Strait and at approxi- 

 mately the same localities as previously in 

 Bristol Bay. A small per cent of returns 

 were east along the south of the peninsula 

 as far as Cook Inlet. According to Gilbert 

 and Rich (1927b), "two of the best-known 

 red salmon streams in Alaska are the Kar- 

 luk River, on Kodiak Island and the Chig- 

 nik River ' ' on the south shore of the penin- 

 sula about half way between Kodiak Island 

 and the Shumagin Islands. "... their 

 runs are nowhere subject to any consider- 

 able commercial capture except in the vicin- 

 ity of their respective mouths." There is 

 no doubt that some of the red salmon in 



the waters in the vicinity of these two 

 rivers, but not close in, move toward the 

 east. Red salmon tagged at Unga Island 

 were captured as far east as Cook Inlet and 

 must have passed these two rivers, but 

 again not close in. The author has found 

 no observations in any paper that he has 

 read (see bibliography), that indicates the 

 salmon east of the Shumagin Islands ever 

 move west. 



When it is learned that there is a cur- 

 rent, or at least a drift, from Bristol Bay 

 toward the west, and a part of this water 

 passes from Bering Sea through Isanotski 

 Strait into the Pacific Ocean these observa- 

 tions just recounted take on a new light.^ 

 Going into further detail, the Cape Pankof 

 Peninsula, and to a less extent, Sanak 

 Island constitute a barrier to the west and 

 Thin Point and Deer Island constitute a 

 more efficient barrier on the east to the 

 Ikatan and Morzhovoi Bays area (Fig. 1). 

 Thus, waters from Bering Sea (Bristol Bay 

 region) would spread giving a very slight 

 gradient of these waters — a fresh-salt water 

 gradient. This gradient would be so deli- 

 cate, and quite often interrupted by waters 

 coming in from outside through the not 

 complete barriers just mentioned, that the 

 red salmon would be retained in this area 

 some time (some fish as long as three weeks 

 or so according to Gilbert, 1924, and Gil- 

 bert and Rich, 1927a). At no time would 

 these fish leave this area to the south, west 

 or east, since there would always be a more 

 or less steep salt-fresh water gradient be- 

 tween the waters of this area and the less 

 diluted sea water constituting the west- 

 ward oceanic drift of the Pacific. After 



2 Captain G. S. Bryan, United States Navy, per- 

 sonal communication states, "While there have 

 never been extensive studies made of the currents 

 in the Bering Sea, according to the U. S. Coast 

 Pilot, Alaska, Part II, 1931, the current in Bering 

 Strait sets northward with a normal velocity of 

 about two knots. The currents in Bristol Bay are 

 usually considered as partly tidal, although a 

 strong northeast storm will cause a strong current 

 to sweep out of the bay. Aside from tidal influ- 

 ences, there is a permanent eddy that enters past 

 Cape Newenham, flows eastward and discharges 

 along the north shore of Unimak Island flowing 

 westward. ' ' 



