Ornamental fish trade is one of the fastest growing fisheries sectors all over the world and the Spotted Scat (Scatophagus argus), a brackishwater ornamental fish, which can be maintained in freshwater, brackishwater and marine aquaria is a suitable candidate species for promoting as an ornamental fish. Considering the potential of this species, the Central Institute of Brackishwater Aquaculture (CIBA), Chennai initiated breeding and propagation of Scat as a thrust area. Captive land based broodstock of Scat (48 – 254 g) was developed in pond and tanks and the fishes were provided with the required environmental conditions for accelerating maturation under captive conditions.
Successful spawning of the captive broodstock was achieved for the first time in India using the brood fishes developed under controlled conditions. A female fish weighing 200 g with ova diameter of 426 µ was selected and administered with Human Chorionic Gonadotropin (HCG) hormone as a prime dose followed by Luteinizing Hormone and Releasing Hormone (LHRHa) as a resolving dose. The male fishes were also administered with the same hormones. After 48 hrs of hormonal treatment, the fishes responded and ovulation was observed.
The ovulated eggs and milt were stripped from the fishes and fertilization was facilitated externally. Larvae hatched out after 19 hrs of fertilization and the average size of the larvae was 1.62 mm. The larvae were fed with rotifers from 3rd day up to 10th day and afterwards with the brine shrimp Artemia nauplii up to 25th day, till they reached 7-9 mm size. Later, the fry were weaned to formulated feed and reared further. The hatchery produced juveniles were supplied to entrepreneurs for further propagation. The technology was developed in CIBA by Dr.M.Kailasam, Senior Scientist, Dr.A.Thirunavukkarasu, Principal Scientist and Head, Fish Culture Division and their team.
The two inch size Scat can be sold @ Rs. 30/pc in local markets and it fetches US $ 2 /pc in the international markets. The technology developed in CIBA for mass scale propagation of scat will open