MASS PRODUCTION OF PEARL SPOT Etroplus suratensis IN BRACKISH WATER LINED PONDS USING HUMAN GONADOTROPHIC HORMONE

Of the 12 trials conducted in triplicates using Ovaprim, Ovatide, WOVA FH and HCG in 3 different doses in 300 lit FRP tanks, HCG hormone was most effective in inducing spawning of pearl spot in FRP tank. Then the concentration HCG was standardised. Of the concentration 100 IU, 500 IU, 1000 IU, 1500 IU & 2000 IU per kg evaluated, 1500 IU/ kg has given the best results. Based on the primary results, mass breeding of pearl spot in polythene Lined pond of 80 square meter area in Brackishwater using HCG (1500IU/Kg) was attempted in duplicate and the experiment was repeated 3 times. The matured healthy brooders of Avg. length;16.2 cm and weight; 115.1g were selected and induced with HCG hormone @ 1500 IU kg^-1 of fish in the intraperitoneal region (Fig.1). The induced bred fishes were immediately released into the polythene lined ponds.. The pond was provided with pipes for the flower pots for hiding and for adhesion of eggs. The sex ratio of 1:1 was maintained throughout the study. Totally 18 brooders were used for the study. After the eggs are laid by the female and are stuck to the substratum one by one, the male fish fertilizes them immediately. The process of egg laying and fertilization continues several times and the eggs are cemented closely without touching each other. As the yolk is fully utilized, within a week, the wrigglers develop their locomotor abilities and become free swimming and the larvae gradually move in pond surface in schools and swim freely in to the open waters. More than 3000 young ones were harvested from the brackish water lined ponds. The parental patronage is continued for about two months till the young ones scatter out and move freely for search of particulate food materials.