Induced breeding and early development of Villorita cyprlnoides Var cochinensis with comments on hatchery system

Abstract

Villorita cyprinoides is an important resource which can be developed in low saline conditions Of the estuarine systems. Villorita cyprinordes var cochinensis is induced to spawn in the laboratory By adjusting the hydrogen ion concentration. The eggs measuring 56 p develop into trochophore stage by 19 h after fertilization and become '0' shaped larvae (95 p) by 29h By about 11 days the larvae (140 p) Show signs of settlement but continue planktonic life up to 26 days when they (450 to 500 p) settle at Bottom. The laboratory temperature ranged from 27.5OC to 34OC end the salinity ranged from 17.2% to 18.35%. Even though the larvae could survive in almost fresh water condition during late stage of development Salinity above 19x0 is found to be detrimental to the larvae. The advantages of using hapa system For hatchery purpose is also presented in the paper.