高知県古満目漁場に来遊するブリ産卵群とシナホリンによる成熟促進について

概要

論文の詳細を見る
The present paper dealt with some ecological findings of the spawning shoals of the yellowtail migrated to the fishing ground, Komame, Kochi Pref., (Fig. 1) in May of 1966, and induction of spawning with“synahorin” injection. The shoals of this fish treated here are mainly composed of rather small fish, as heavy as about 5kg in body weight (Fig. 2). All of the male fish examined are enough ripened, the sperm easily runs out from the body by the external pressure. Although the female fish vary from individual to individual in maturity, the ones belonging to the middle mature stage, in which the gonad is well enlarged, the largest ovarian eggs reach 0.50 to 0.70mm in diameter, are dominant in number at the beginning of May. While, in the middle of this month the full mature female having larger eggs ranging from 0.8 to 1.0mm in diameter are numerous. Some ripe ones are also found throughout the season examined, but they do not beyond 9% of total fish migrated here. Based on the result obtained, it can safely concluded that this fishing ground seems to be a spawning area for the Pacific population of the yellowtail. The ovaries of the yellowtail reaching 70cm in fork length, injected with “synahorin” rapidly increase in their weight (Table 1), and with ripe eggs, 1.15 to 1.25mm in diameter, in one or two days after injected (Table 2, Fig. 3).
公益社団法人日本水産学会の論文