Abstract
A defensive conditioned reflex was established in groups of fry of hatchery-reared and wild-born chum salmon, Onchorhynchus keta (Walbaum), using a plastic model of predatory fish as conditioned stimulus and an electric shock as unconditioned stimulus. Efficiency of elaboration, stability, and retention of the conditioned reflex were improved with age. In a group in which the majority of fish had been well conditioned, the poorly-reinforced minority followed the prevailing defensive movement of the majority group. The reflex to the fish model was readily generalized i.e., extended to other objects. Wild fry showed naturally-acquired, defensive behavior against the fish-model in the laboratory. Some artificially reinforced groups were marked on their fins and released upstream in a closed, experimental river-area, being recaptured downstream. The relatively high rate of survival in these groups proved the effectiveness of the elaborated defensive reflex against natural predators.
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Literature cited
Antal, J. and A. Kemény: The rate of elaboration of alimentary and defensive reflexes. Physiologia bohemoslov. 13, 110–116 (1964).
de Lury, D. B.: On the planning of experiments for the estimation of fish populations. J. Fish. Res. Bd Can. 8, 281–307 (1951).
Hikita, T. and A. Nagasawa: Biological observations of Memu stream, Tokachi river system. The damage of salmon eggs and fry by predaceous fishes. [Japan.] Scient. Rep. Hokkaido Salm. Hatch. 15, 69–83 (1960).
Hoar, W. S.: The evolution of migratory behaviour among juvenile salmon of the genus Onchorhynchus. J. Fish. Res. Bd Can. 15, 391–428 (1958).
Kanayama, Y., Y. Kodama and H. Tuge: Studies of the conditioned reflex in the lower vertebrates. IX. Defensive conditioned reflex of the fish larvae in group. [Japan.] A. Rep. Noto Mar. Lab. 4, 3–8 (1964).
Kobayashi, T.: An ecological study on the salmon fry, Onchorhynchus keta. V. The behaviour of chum salmon fry on their seaward migration. [Japan.] Scient. Rep. Hokkaido Salm. Hatch. 12, 21–30 (1958)
—: An ecological study on the salmon fry, Onchorhynchus keta (Walbaum). VII. Note on the behaviour of the fry on their seaward migration. [Japan.] Scient. Rep. Hokkaido Salm. Hatch. 18, 1–6 (1964)
Kuroki, T.: Dengeki giyoho (Electric fishery). [Japan.], 189 pp. Tokyo: Gihodo 1955.
Neave, F.: Principles affecting the size of pink and chum salmon populations in British Columbia. J. Fish. Res. Bd Can. 9, 450–491 (1953).
—: Notes on the seaward migration of pink and chum salmon fry. J. Fish. Res. Bd Can. 12, 369–374 (1955).
Popov, T. B.: Studies of the defensive conditioned reflex in the fish larvae. [Russ.] Zh. vyssh. nerv. Deyat. I. P. Pavlova 3, 774–788 (1953).
Shiraishi, Y. and M. Takagi: Food habit of trout in lake Yunoko, with reference to the morphology of body and digestive organs. [Japan.] Bull. Freshwat. Fish. Res. Lab., Tokyo 5, 11–30 (1955)
Tarrant, R. M. Jr: Rate of extinction of a conditioned response in juvenile sockeye salmon. Trans. Am. Fish. Soc. 93, 339–401 (1964).
Tuge, H., A. Ir, Y. Kanayama and H. Ochiai: Studies of the conditioned reflex in the lower vertebrates. I. Gold-fish and sea bream (Pagrosomus major). Sci. Rep. Tôhoku Univ., Ser. 4, 21, 227–240 (1955).
— and H. Ochiai: Studies of the conditioned reflex in the lower vertebrates. II. Early development of the defensive conditioned reactions in fish larvae. Sci. Rep. Tôhoku Univ., Ser. 4, 22, 21–28 (1956).
Welty, J. C.: Experiments in group behaviour of fishes. Physiol. Zoöl. 7, 85–128 (1934).
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Communicated by M. Anraku, Nagasaki
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Kanayama, Y. Studies of the conditioned reflex in lower vertebrates. Marine Biol. 2, 77–87 (1968). https://doi.org/10.1007/BF00351643
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DOI: https://doi.org/10.1007/BF00351643