サバの〓游路
スポンサーリンク
概要
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The review of the works conducted in the past has brought the conclusions as follows on the recapture of tagged fish as well as course and season of migration for Japanese mackerel. 1. In the Sea of Japan, the rate of recapture was found to be 0.92% against the number of liberation for Japanese islands, whereas it was 0.51% for the eastern coast of Korea. In the pacific coast of Japanese islands, the same rate was 0.80%. These figures indicate very low rate of recapture compared to those obtained for yellowtail. 2. The number of recapure show peak figures during 41 to 50 days after the release, but they are very low immediately after the liberation. Considerable number of tagged fish were also caught as late as one to two years after the release. 3. n (the number of recapture) and t (the elapsion of days after the release) may be expressed by an exponential equation. (Fig. 2), n=5×10-0.0017t. The same equation was calculated for yellowtail as n=10×10-0.0017t 4. The route of migratiou may be summarized as follows: (i) The shoals migrating southward along Korean coast in fall arrive Korean Strait, thence the fish, in spring and summer of the following year, enter northward migration but in two split shoals, the one along Korean eastern coast and the other along the northern shcre of Japanese islands. (ii) There seems, to be a "fish way" connecting the west side of Oki Island and Kogendo, Korea, which is observed in the months of May to September. (iii) The study also indicates the existence of another "fish way" which, seen in summer months, runs from Yamato Bank in central part of Sea of Japan to Kankyôhokudô, Korea. (iv) The mackerel in Sea of Japan show both north-and southward migration within a year, but there is a tendency that the fish of older ages have center of their migration in southern waters within range of moving.
- 社団法人 日本水産学会の論文