Simplified hatchery protocols for culture of orange-spotted spinefoot siganus guttatus (Bloch, 1787) in Palawan, Philippines

Abstract

Three hatchery experiments for orange-spotted spinefoot, Siganus guttatus (Bloch, 1787), were carried out in Puerto Princesa City, Palawan, Philippines using larvae and fingerlings produced through induced spawning. The first experiment (E1) involving larvae raised in six 5,000-L concrete tanks until 39 days post-hatch (dph) comparing two stocking densities(T1:3; andT2: 5 larva.L1), obtained survival rates(SR)of 6.00 and 7.85 %. The second experiment(E2) monitored the growth and survival of 47 dph juveniles for 3 weeks, raised in 25-L plastic basins, fed with a commercial diet at three stocking densities with five replications. The initial stocking densities (6,12,18 ind.L-1)were reduced during the second (4,8,12 ind.L-1) and third (2,4, 6 ind.L-1)week, respectively. The weekly SR for all treatments ranged between 99.2 and 100 %. Weekly final total lengths (TL) were not significantly different except during the second week. The third experiment (E3) evaluated the effects of two types of commercial feeds (T1: Grouper feed; T2: Milkfish feed) on the growth and survival of 47 dph juveniles in plastic basins for 3 weeks, at similar densities reduced on a weekly basis. The SR (96.2 to 99.9 %)were not significantly different, but the TL offish in T1 (4.39 cm) were significantly bigger than in T2 (3.52 cm). While there is a need to improve the low and irregular survival of S. guttatus larvae for cost-effective large- scale production, we recommend using small basins in the intensive rearing of juveniles.