太平洋および印度洋におけるシイラ Coryphaena hippurus L., の地理的分布について

概要

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The geographical distribution of dolphins hooked by tuna long line in the Pacific Ocean and The Indian Ocean Were investigated. It was the sea area within latitude 30 degree of both semispheres where dolphins were hooked by tuna long lines, and it is needless to say the area is ristricted in the tuna fishing grounds. The surface water temperature when dolphins were hooked ranged from 21°C to 30°C, and it was suggested that dolphins are distributed all the year round in the area within latitude 30 degree. The mean body weight of the fish ranged from 1 to 30kg, and the majority were 5 to 10kg. In the South Pacific Ocean, dolphins hooked during May to August were small in size, and large ones occurred during November to February. The changes of fishing season and fishing grounds in the Southern hemisphere were the exact opposite to those in the Northern hemisphere, therefore there is a fair possibility of existence of two different races each is inhabiting Southern hemisphere and Northern hemisphere, respectively.
公益社団法人日本水産学会の論文