Seasonal Changes in Gonadosomatic Index, Hepatosomatic Index and Condition Factor of Marbled Sole Pleuronectes yokohamae in Harima-Nada to Osaka Bay, Seto Inland Sea, Japan

概要

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To determine the life history of the marbled sole <I>Pleuyonectes yokohamae</I> in the Harima-Nada and Osaka Bay waters, gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factors (CF1 and CF2, with and without gonads, respectively) of the species were examined in the periods of July 1986-January 1989 (late 1980s) and June 1998-January 2001 (early 2000s) . The life cycle of the marbled sole was classified into the following three stages: recovering stage (February-May), immature & maturing stage (June-November) and spawning stage (December-January) . Seasonal variations of the GSI and CF2 were similar between the periods of the late 1980s and the early 2000s. Successive three-year monitoring of the 1986 cohort in the present study clarified specific seasonal changes of the indices. Maximum value of HSI was observed in July in both sexes, and the index peaked secondarily before the spawning season in female. The value of CF1 temporarily increased during the spawning season, while that of CF2 increased in summer and then decreased before and through the spawning season.
日本水産増殖学会の論文