independently several times. It would appear that 

 any tish that has latoral-line organs possessing even 

 secondary electrical sensitivity could develop an 

 electronavigation system relatively easily and 

 quickly. For example, the galvanotropism of the 

 catfish Parasiluru^s (Abe, 1935) seems to be such 

 a development. Although we have no physiological 

 information to confirm electronavigation on the 

 high seas for salmon, the circumstantial evidence 

 described above indicates that it should be 

 included among the more likely sensory mecha- 

 nisms that salmon may use during their travels. 



CONCLUSIONS ON GUIDANCE MECHANISMS 



We believe that the salmons' migration cannot 

 bo i^erformed if they migrate or drift at random, 

 or if they depend on any memorized visual or olfac- 

 tory cues at any time except during the final loca- 

 tion of the home estuary and stream. We note that 

 the salmon predominantly travel actively with the 

 ocean currents in circular migration routes. Many 

 races could accomplish their migrations by mov- 

 ing down or across currents until close to the 

 mouths of their home streams, where they might 

 recall memorized olfactory cues. We note also that 

 ocean currents produce electric potentials in a 

 range which some fish can detect. We suggest, 

 therefore, that salmon may depend on electro- 

 inagiaetic cues from ocean currents. We suggest 

 further that their response to all migatory cues is 

 inherited, not, memorized. 



LITERATURE CITED 



Abe. \oboru. 



1935. Galvanotropism of the catfisli : Para.tilurus aso- 

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 Amos, Mukray H.. Raymond E. .Vnas. and Rogeu E. 

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1963. Use of a discriminant function in the morpho- 

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Brown, Frank A.. .Jr., Franklin H. Barnwell, and H. 

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1964. Adaptation of the magnetoreceptive mechanism 

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BtTREAU OF COMMEBCIAL FISHERIES. 



1957-65. Sea surface temperature charts, eastern 

 Pacific Ocean [May. .Tune, .July]. In California 

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Wildl. Sorv., Bur. Com. Fish. (1907-59— POFI, 

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 Diego, Calif.; Nov. 1964-1965— TTuna Resources 

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Callaway, Richako .1. 



1963. Ocean conditions in the vicinity of the Aleutian 

 Islands, su.-nmer 1957. Int. N. Pac. Fish. Comm., 

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Dell, Michaei, B. 



1963. Oceanic fee<ling habits of the sockeye salmon. 

 Oncorhyiwhus ncrka (Walbaum), in Aleutian wa- 

 ters. M. S. Tliesis, Univ. Mich., Ann Arbor, 40 pp. 



Dijkgraaf, S. 



1963. The functioning and significance of the lateral- 

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DoDi>fEAD, A. J., F. Favorite, and T. Hirano. 



1963. Salmon of the North Pacific Ocean. Part II. 

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Engek, Per S., and Tiio.mas Szabo. 



1965. Activity of central neurons involved in eloclro- 

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Favorite, Fexjx, and Mitchexl G. Hanavan. 



1963. Oceanographic conditions and salmon distriliu- 

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 57-72. 



Fisheries Research Board ok Canada. 



1962-66. Re.searc-h Ijy Canada. In Int. N. Pac. Fish. 



Comm., Annual reports for years 1961-65. Int. N. 



Pac. Fish. Comm.. A'ancouvcr. Canada. [Various 



pagination.! 

 French, Robert R. 



1964. Salmon distribution and abundance on tlio high 

 seas — summer sea.son 1963. Int. N. Pac. Fish. Comm., 

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1966. Salmon di-stribution and abundance studies. Int. 

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French, R., and J. E. Mason. 



1964. Salmon distribution and abundance on the high 

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FuKUHARA, Francis .M.. Sueto Mikai. .Iohn .(. LaLanne, 

 and Abporna Sribiiibhadii. 



1962. Continental origin of red salmon as determined 

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 GiLHOusE.N, Philip. 



1962. Main factors affecting the survival of Fraser 

 River pink .salmon. In N. .7. Wilimovsky (editor), 

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GoDFRBTY, Harold. 



1965. Ooho salmon. Int. N. Pac. Fish. Comm., Bull. 

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Hagiwara, S., and II. Morita. 



1963. Coding mechanisms of electroreceptor fibers in 

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460 



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