THE FEEDING MANAGEMENT OF GROUPER (Epinephelus sp.) LARVAE FROM THE CROSS-BREEDING SPAWNING PRODUCT IN BULELENG BALI

Abstract

High mortality in larvae emerges due to less suitable size and nutritional contents of the feed for larval requirement. Therefore, live feed management is one of the successive factors in many grouper hatcheries to reduce high mortality risk in larval stage and provide good nutritional value in fish. This article reviewed the feeding management of grouper larvae and the obstacles occurred during the feeding management within the larval rearing period in Buleleng, Bali. The grouper larvae were produced from the cross-breeding process between female tiger grouper (E. fuscoguttatus) and male marbled grouper (E. polyphekadion). Rotifers (Branchionus plicatilis) were enriched with marine green microalgae (Nannochloropsis oculata) at 2 × 105 ind/ml. Rotifers were then fed to the larvae at 1-3 ind/ml. This feeding application was performed when the larvae was at 2-7 DAH (days after hatching). Artemia salina was fed to the 17-DAH larvae at 0.2-0.5 ind/ml, then increased at 8 ind/ml as the larvae reached 27 DAH with four-time feeding frequency. Also, commercial feed was provided for the larvae at 15 DAH and small shrimp (Acetes sp.) was fed to the 40-DAH larvae for supplement. This feeding management could produce a good absolute length growth rate at 22.3 mm on 35 days of rearing. However, high mortality rate was still occurred due to cannibalism, high stocking density of rotifers, and fluctuated weather that decreased the live feed supply. Thus, additional nutrient enrichment and optimal larval consumption observation should be performed to reduce high mortality rate, cannibalism, and weather condition influence.