The commercial production of green grouper fingerlings, Epinephelus suillus, from wild caught fry - an industry experience

Abstract

Wild-caught fry of the green groupers, Epinephelus malabaricus and E. suillus ranging in standard lengths (SL) from 1.5 to 3.0 cm were bought from different fry dealers all over the Philippines. These were reared from 1.0 to 2.5 months in 10 to 40 m3 (small) concrete tanks, in 240 m3 (large) concrete nursery tanks with sandy bottom, in 10 m3 hapa nets installed either in large nursery concrete tanks with sandy bottom or in 0.8 to 1.0 ha earthen ponds. The initial stocking density was 33-150/m3. When the fingerlings reached 5 to 7 cm SL, these were harvested and stocked in cages. The wild fry were fed adult brine shrimps for the first few days and later, trash fish. Rearing water in small concrete tanks was changed daily while that in large nursery tanks and hapas was changed only when dissolved oxygen level was about 4 ppt or lower. Survival rates ranged from 3% to 64%. Although survival rates varied, rearing grouper fry in hapa nets installed in earthen ponds were found to be the most suitable for the commercial production of grouper fingerlings to a size suitable for stocking in cages. The large variation in survival rates is attributed mainly to the quality of wild fry bought from different fry dealers all over the country and the occurrence of diseases during the culture period. The problems encountered in the commercial production of fingerlings are discussed.