Pijah rangsang dan pemeliharaan larva kerapu lumpur (Epinephelus tauvina)

Induced Spawning and Larval Rearing of Estuary Grouper, Epinephelus tauvina (Forskal). Epinephelus tauvina is commercially one of the most important fish species and highly esteemed as food fish in Singapore, Hongkong, Taiwan, Malaysia and Indonesia. Furthermore, since this species seem suitable for culture of floating net-cages and ponds, the development of hatchery techniques is essential to produce large supplies of fries. Female and male were used for spawn around 5-8 and 9 - 15 kg in body weight. The grouper is a protogynous hermaphrodite with females transforming into males at around 650 - 750 mm in body length. Induced spawning is one method using a single intramuscular injection of either Human Chorionic Gonadotropine (HCG) with dosage ranged 500-1,000 IU/kg body weight. Polycarbonate, fiberglass and concrete tank of 0.5, 1.0 and 3.0 m^ in volume were used for larval rearing of grouper. The fertilized eggs measure 0. 71 to 0.90 mm in diameter while the hatched larvae are 1.4 to 2.4 mm in total length. The larvae were reared using rotifers, nauplii artemia, copepods and minced shrimp meat or transhish. Larvae grew from 2.25 mm total length at hatching to 31.40 mm by day 50. Two mortality peaks were observed : the first between days 4 and 5, and the second between days 24 and 35.