MAIDEN HARVEST OF CAGE CULTURED SILVER POMPANO Trachinotus blochii IN ANDAMAN WATERS
In order to popularise cage culture technology of marine fin fishes among the fishers and fish farmers, demonstration of grow-out farming of silver pompano, Trachinotus blochii was carried out using galvanised iron (GI) cages for the first time in the Andaman and Nicobar Islands. An established model of GI cage design of 6m diameter in Indian waters was deployed at Minnie Bay, South Andaman (Fig1).
Hatchery produced seeds of silver pompano (av. length: 5.54 cm and av. weight 3.1 g) procured from RGCA, Vizhinjam were initially reared in hapa for about 2 months until they reached 30-40 g size. These fishes were then stocked in circular GI cage (Fig 2) at a stocking density of 30/m3. The fishes were fed initially 3 times with formulated feed (45% protein) for 2 months during hapa rearing and thereafter fed twice at 5% body weight with chopped trash fish until harvest. The water quality parameters were observed to be in the optimum range viz., pH: 7.5 - 8.5, DO: 5.5 - 6.5 ppm, temperature: 27ºC - 29ºC and salinity: 20 - 27 ppt. The growth parameters of the fishes were monitored throughout the culture period using monthly random sampling. The fishes were harvested after 270 days of culture during which they reached an average length of 28.22 cm and average weight of 325.54 g. The cage design endured the catastrophic "Vardah" cyclone that hit the Islands during first quarter of December, 2016. This is the first successful harvest of silver pompano in Andaman waters in a cage design perfected for mainland coastal waters. Silver pompano with its good meat quality, high market demand and its amenability to culture in low saline waters promises to be a good candidate species for cage culture even in the estuarine, brackishwater and inundated saline areas of the Islands.
