Annual life cycle of adult marbled sole Pleuronectes yokohamae in the coastal waters around Kikonai Bay, Hokkaido, Japan

Pleuronectes yokohamae

日本水産増殖学会

水産増殖

To clarify the annual life cycle of adult marbled sole Pleuronectes yokohamae in the coastal waters around Kikonai Bay, the seasonal changes in gonadosomatic index, hepatosomatic index, and condition factor of samples obtained with commercial set nets and research bottom trawl nets during May 1994 through October 1996 were examined. In addition, feeding intensity was investigated using a stomach contents index and noting the percentage of empty stomach. The annual life cycle of adult P. yokohamae was divided into the following three periods: spawning (February-April), active feeding and recovering (May-July), and inactive feeding (August-January). The inactive feeding period was further divided into two sub-periods: immature (August-October) and mature (November-January). It seems likely that P. yokohamae in this study area feeds intensively after spawning and matures under these high levels of nutrition.