Abstract
Studies on the maturity and spawning season as the biological parameters of finespotted flounder Pleuronichthys cornutus in Suõ-Nada of Seto Inland Sea were not established yet.
Based on the seasonal change of the maturity factor and results of the observation of gonads by the naked eye, evaluation of the degree of sexual maturity, main spawning season, body length and age at 50% sexual maturity were over 1.0 in both sexes, 11.0cm in females and 9.0cm in males respectively. Each age at 50% sexual maturity at age 0, 1, 2, 3 over 4 years was 70, 90, 100, 100% in females and 90, 95, 100, 100, 100% in males, respectively.
Main spawning season was the beginning of November.
The duration of maturity of male finespotted flounder is longer than that of female
The beginning of the period of maturity of aged individuals was earlier than younger ones.
