千葉県館山湾におけるアイゴの生活年周期

概要

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Annual life cycle of rabbitfish Siganus fuscescens were examined in Tateyama Bay, Chiba Prefecture. A total of 1775 specimens (35-339mm BL) were collected by set net and dip net from 2005 to 2007. Rabbitfish were caught by the set net from May to December when the water temperature was over 17.5℃. From the seasonal changes in gonad somatic index and ovarian maturity, the spawning season was estimated to occur from July to August. The minimum size for maturation was 155mm BL in males and 168mm BL in females. Young rabbitfish (35-43mm BL) were caught by the dip net in October after the spawning season. This result suggested that the rabbitfish were reproduced in Tateyama Bay. Frequency of occurrence in gut contents of adult rabbitfish were 48.1% in brown algae, 22.9% in red algae, 17.5% in green algae, 12.5% in hydroid, and 7.4% in caprellid amphipod. Gonad somatic index inversely correlated with gut contents somatic index.
2009-11-15