Growth and production potential of young grouper Epinephelus tauvina (Forskal) reared in fixed net cages

Abstract

Growth of Epinephelus tauvina was studied in the fixed cage culture system in Mandapam (Gulf of Mannar) coastal waters employing net cages of 5 x 5 x 2 m dimension made of HDPE net material with 20 mm mesh size. The fishes were fed with trash-fish once in 2 days arid the culture period varied from 163 days to 334 days. The average growth increment in length was 145.5 mm in 8.71 months at the rate of 16.3 mm/month and the average growth increment in weight was 413.9 g at the rate of 47.5 g/month. The basic growth data were subjected to various statistical analysis and different para- meters have been estimated. The asymptotic growth Loc is 671 mm, the growth constant K is 0.4619 and the age at 0 k*gth t«^is assumed to be O. The life span is estimated to be 10.7 yrs and the natural mortality coefficient M is 0.4333 at 1 % survival level. The optimum age for harvesting is estimated to be 3 yrs and the optimum culture period which can yielo the highest production for this species is 28 months for the prevailing age at stocking of 8 months. The cost and return of this culture technique is also discussed.