Migration of Yellowtails along the Pacific Coast of Japan Observed by Tagging Experiments-III

Analysis of the Data of Pre-war Period

Abstract

Taggings of a considerable number of yellowtails, Seriola quinqueradiata, were conducted in the pre-war period (1926-1938). The general pattern of migration of this species shown by these experiments is conformable with that obtained from experiments in 1963-1965; the southward migration in spring along the coast of Japan west of Cape Nojima, central Japan, and the northward migration in summer from central to northern Japan, north of Cape Nojima. It seems that the fish group in the Kumanonada and eastern areas intermingled with that off Kyushu in areas off Shikoku. The releases in the Kumanonada area in March and early April presented a trend of southward movement but the releases after early April showed only northward movements. The movement from the Kumanonada to the Sagami Bay and further north was not observed in the post-war period. It may be considered that a part of southward migrants change their direction of movement toward north on their way to south, and that the turning point of these fish was in the Kumanonada in the pre-war period but has shifted toward east to the Sagami Bay in the post-war period.