Induction of gynogenetic diploid in hirame Paralichthys olivaceus

Abstract

The following results were obtained from the experiments toind optimum conditions forinduction of gynogenetic diploids in hirame Paralichthys olivaceus.
The Ringer solutions for Pleuronectes and freshwater fish seem to be adequate as the diluting solution for milt of hirame because spermatozoa aren't motile in either Ringer solution and resisted for at least 3 hours when they were stored at 3°C.
Keeping temperature constant during irradiation is required because the intensity of UV depended on the temperature.
The hatching rate of eggs inseminated with milt irradiated by UV rays was almost 0% at the dosage of 110-230 erg/mn², but it recovered when milt was irradiated with more than 660 erg/mm² and all frys showed to haploid syndrome(n=24).
Gynogenetic diploids of hirame were induced by cold shock treatment-put the fertilised eggsin sea water of0°C for 45-60 min from 2-5 min after insemination with milt irradiated by UV rays at the dosage of 660-1, 380 erg/mm². Heat shocks were not effective for induction of gynogeneticdiPloid.