Gynogenetic induction in marine bivalve molluscs for improvement of stocks: Standardization of some important factors

Abstract

Experiments conducted for standardizing sperm density for artificial insemination of Chlamys mobilis prior to inducing gynogenesis by ultra-violet rays irradiated sperms showed that 10:1 ratio of sperms to eggs should be maintained for getting maximum rate of fertilization and the normal development of the veliger larvae. The optimum quantity and density of sperm suspension recommended for irradiation exposure experiments in 10 ml capacity glass petri dish was 0.5 ml of stock sperm suspension with 20 x 10 super(6) per ml concentration so as to effectively inseminate 2000-2500 eggs in 50 ml of seawater. The results of the preliminary gynogenetic induction experiments performed ascertained the reliability of these parameter limits. In controls, it showed 100% rate of fertilization and 95.00% normality in the form of morulae after 6 hours of insemination and 98.05% metamorphosis and 96.12% normality in the form of normal D-shaped larvae. 24 hours after insemination. The lower values of fertilization, metamorphosis and normality in the other groups were due to the insemination of eggs with the ultra-violet ray irradiated sperms. The gynogenetic haploid larvae with 16 chromosomes were induced