Preliminary studies on the rearing of the red-spotted grouper, Epinephelus coioides larvae using copepod nauplii as initial food

Abstract

One day old red-spotted grouper (Epinephelus coioides) larvae from SEAFDEC, Iloilo, were packed at 3.300 ind/L and transported to Dagupan, Pangasinan for larval rearing. Transport time was about 10 hours. More than 90% of the larvae were active after transport. These were reared in two 7-on tanks (Tanks 1 and 2) using Acartia nauplii and rotifers as a initial food and in one 10-ton tank (Tank 3) provided with rotifers only. Feeding incidence at the onset of feeding (Day 3) was higher (90-95%) in Tanks 1 and 2 than in tank 3 (85%). All larvae sampled from days 4 – 10 in Tanks 1 and 2 had food in the gut while feeding incidence in Tank 3 was variable (75-100%). Larvae in Tanks 1 and 2 showed consistently higher food electivity for Acartia nauplii than rotifers. Higher survival rates were observed in Day 13 in tanks provided with copepod nauplii (16-18%) than with the rotifers only (2%). Average total length on Day 13 was higher in copepod-fed larvae (4.5 ± 0.5 mm) than larvae fed with rotifers only (3.0 ± 0.3mm). All larvae fed with rotifers alone died on Day 15. A total of 675 larvae were harvested on Day 45 from Tanks 1 and 2. These results indicate the feasibility of transporting one day old E. coioides larvae for at least 10 h and of using copepod nauplii as food for the first feeding E. coioides larvae.