MODELS OF OCEANIC MIGRATIONS OF PACIFIC SALMON 

 AND COMMENTS ON GUIDANCE MECHANISMS ^ 



BY William F. Royce, Associate Dean, Lynwood S. Smith, Associate Professor, and Allan C. Hartt, Fishery 



Biologist. FISHERIES RESEARCH INSTITUTE, COLLEGE OF FISHERIES, UNIVERSITY OF WASHINGTON, SEATTLE, 



Washington 98105 



ABSTRACT 



The general oceanic distribution and migratory be- 

 havior of Pacific salmon are summarized, and a model 

 of the entire migration is developed for each of three 

 typical stocks. The pink salmon of southeastern Alaska 

 and British Columbia circle the Gulf of Alaska counter- 

 clockwise within an area generally bounded on the west 

 by long. 155° W. and on the south by lat. 41° N. They 

 travel generally "downstream" in the Alaskan Gyre 

 and the associated currents. The pink salmon of the 

 Karaginski district on East Kamchatka also apparently 

 make a counterclockwise circuit of the Bering Sea and 

 North Pacific Ocean in an area bounded approximately 

 on the west by long. 155° E., on the south by lat. 40° 

 N., on the east by long. 150° W., and on the north by 

 lat. 60° N. Their migratory circuit is generally "down- 

 stream": southward in the East Kamchatka Current, 

 eastward in the Subarctic Current, and finally west- 

 ward and northward in the Alaskan Stream and the 

 Bering Sea Gyre. The sockeye salmon of Bristol Bay 

 make two or three counterclockwise circuits in the 

 Bering Sea and North Pacific Ocean within an area 

 bounded approximately on the north by lat. 60° N., 

 on the west by long. 165° E., on the south by lat. 45° 



The return of the sahnon to its home stream, to 

 the part of the stream wliere its parents spawned, 

 or even to the hatchery where it was reared as a 

 fry has been well documented. Clearly, it is a most 

 unusual animal mijjration. Not only does the salm- 

 on return to its birthplace to spawn and die, but 

 each successive generation appears along the coast, 

 enters the estuary, and ascends to the spawning 

 grounds within a few days of the same schedule. 



The appearance of the salmon in coastal waters 

 and its final ascent of the stream are only the last 

 acts in a most remarkable series of migrations that 



' Contribution 

 Washington. 



No. 209, College of Fisheries. University of 



Published March 1968. 

 FISHERY BULLETIN : 



N., and on the east by long. 140° W. The number of 

 circuits depends upon the number of winters spent by 

 the salmon at sea. In general, they travel "downstream" 

 in the major current systems within the area defined. 

 The time schedule, rate of travel, and average size of 

 the fish at various stages are described for each of the 

 three stocks. 



On the basis of this summary, we believe that the 

 salmons' migrations could not be performed if they 

 migrated or drifted at random, or if they depended on 

 memorized visual or olfactory cues except for final 

 location of the home estuary and stream. The salmon 

 predominantly travel actively with the residual ocean 

 currents in circular migration routes. Many races 

 could accomplish their migrations by moving down or 

 across currents until close to the mouths of their 

 home streams, where they might recall memorized 

 olfactory cues. Also, ocean currents produce electric 

 potentials in a range that some fish can detect; there- 

 fore, salmon might depend for navigation on electro- 

 magnetic cues from ocean currents. Furthermore, 

 their responses to all migratory cues must be inherited, 

 not memorized. 



have been studied only recently in enough detail 

 to permit a reasonably comprehensive description. 

 The impetus for the study developed when Canada, 

 Japan, and the United States agreed on a conven- 

 tion concerning North Pacific salmon which re- 

 quired that the high-seas migrations of major 

 stocks of salmon near long. 175° W. and the 

 Aleutian Islands be learned in detail. Beginning in 

 1955 programs were financed to study the abun- 

 dance, migration, and habits of the salmon in the 

 central North Pacific and the Bering Sea and to 

 learn mucli more about their environment. Tlie.sc 

 studies have expanded to include the range of the 

 salmon on both sides of the North Pacific, so that 



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