Growth, Survival and Maturation in the Induced Triploid Hirame Paralichthys olivaceus

Abstract

The growth, survival and maturation of induced triploids were compared with diploid control for 31 months after hatching in hirame Paralichthys olivaceus.
The growth of triploids was lower in the early stage after the hatching than diploids, but there are no differences in other stages. The survival rate of triploids was conspicuously lower in two stages, namely the early stage after hatching and the stage startingto feed the frozen fish. No retarding period of the growth was observed even in the spawning season in diploids which grew continuously as same as triploids. The gonadosomatis index of females continued to increase throughout the experimental term in both diploids and triploids, but increasing rate of triploid females was extremely low. Theprogress of gonadosomatic index of male was almost same as diploids. It was concluded that triploids were completely sterile in both sexes from the histological and the scanning electron microscopical observation and the mating test.