FiGUBE 7. — Diagram of ocean migrations of pinlc salmon 

 stocks originating in soutlieastern Alaska and British 

 Columbia. 



directed and rapid tliau that of the southeastern 

 Alaska-British Columbia pink salmon, jierhaps 

 because the East Kamchatka stocks have a more 

 limited time of arrival. 



Recoveries of tagged pink salmon at sea suggest 

 that the fish migrate rather directly toward their 

 coastal destination from the point of release (fig. 

 8). Tshida (1960) suggested that the lish appar- 

 ently follow parallel courses toward the Karagin- 

 ski district from whatever point they enter the 

 Bering Sea. Such an ability to navigate toward 

 "home" is in agreement with Neave's thesis (1964) 

 that to perform the observed migrations salmon at 

 sea must maintain "bico-ordinate orientation" (i.e., 

 oriented with respect to "home"' in two components 

 such as east-west and north-south). 



The postulated migration of East Kamchatka 

 pink salmon is diagrammed in figure 9. The first 

 two steps — migration downstream in the East 

 Kamchatka Current and in the Subarctic Current 

 and "West wind Drift — are assumed (figs. 1 and 9). 

 Direction appears to change abruptly as they de- 

 part the eastward-flowing Subarctic Current and 

 join the westward-flowing Alaskan Stream. The 

 influence of the Bering Sea Gyre on the migration 

 route is unknown, but the tagging data illustrated 

 in figure S indicate that migration continues rather 

 directly through tiie Gyre. 



A significant feature of the migration of the 

 Karaginski pink salmon is that throughout much 

 of their route during their last 60 to 90 days at sea 



tliey are intenningled little witli other pink salmon 

 stocks although tliey are extensively intermingled 

 with sockeye and chum salmon. In the western part 

 of their distribution they are mixed with West 

 Kamchatka and other Sea of Okhotsk stocks, 

 aiul in the eastern extreme they mix with 

 Gulf of Alaska stocks (Haitt, 1966). In the 

 central part of their weanic range they arc 

 mixed only with the relatively minor Aleutian and 

 western Alaska stocks. Tagging data indicate that 

 their distribution is probably just as extensive in 

 even-numbered years of low abundance as in odd- 

 numbered years of high abundance. In addition, 

 the abundant West Kamchatka or Gulf of Alaska 

 stocks do not mo\-e into the central Aleutian area 

 in years when the East Kamchatka stocks are 

 scarce (Hartt, 1966; Kondo et al., 1965). These ob- 

 servations indicate that oceanic-migration patterns 

 are independent of abundance within or between 

 individual stocks. 



OCEAN MIGRATIONS OF SOCKEYE 

 SALMON OF BRISTOL BAY 



Bristol Bay stocks are defined herein as those 

 originating in the eastern Bering Sea between 

 the northern side of T'nimak Island and the 

 Kuskokwim River (fig. 10): fish originating 

 within this area migi-ate similarly at sea. Xearly all 

 originate in five main river systems — Nushagak. 

 Kvichak, Xaknek, Egegik. and T'gashik— whicJi 

 enter at the head of Bristol Bay near lat. r)8° X., 

 long. 1.57° W. (fig. 10). These stocks make up the 

 largest sockeye salmon run in the world, between (> 

 and 60 million mature fish per year. The annual 

 average for 1956-65 was 23.9 million (Ossiander, 

 1965: Pacific Fisherman, 1966). 



The life history of Bristol Bay sockeye salmon, 

 although variable, may be described in general as 

 follows. Spawning takes j)lace in August and Sejj- 

 tember in the vast Bristol Bay lake systems. Fry 

 emerge mainly in June. The young fi-sh generally 

 spend 1 or 2 winters in fresh water and migrate 

 to sea as 2- or 3-year-old smolts. Downstream mi- 

 gration is mainly in June, simultaneously with or 

 immediately after breakup of the lake ice. Most 

 then spend 2 or 3 years at sea so that their total 

 age at maturity is usually 4, 5, or 6 years with vari- 

 ous combinations of fresh-water and salt-water 

 age. Tiie returning run migrates through the 

 estuaries fi-oni about June 20 through Julv 25, but 



448 



U.S. FISH .\Xn WILDI.TFIO SERVICK 



