Sex-age structure and reproduction of yellowfin sole Limanda aspera in the eastern part of the Okhotsk Sea

Abstract

Data on sex ratio and size-age composition of yellowfin sole Limanda aspera Pallas [1814] in the eastern Okhotsk Sea are generalized. The sex structure is significantly different for mature and immature parts of this stock. Natural losses of both males and females depend on their year-class strength: the stronger the generation, the higher mortality. Besides, their maturing depends on the year-class strength, too: both males and females of high-abundant generations mature later, and rate of their gonads maturation decreases for elder age groups. Favorable environmental conditions supposedly promote growth of spawning stock with increasing of the females portion. So, for weak or mediate year-classes the leading increase of females provides an abundant recruitment at the beginning, but further the growing misbalance of sex ratio can effect on the reproduction negatively. However, dynamics of progeny correlates stronger with spawning stock than with sex ratio.