GROWTH AND SURVIVAL OF THE SEA CUCUMBER Holothuria scabra LARVAE AT DIFFERENT FEEDING REGIMES

Sandfish (Holothuria scabra) is one of the most widely cultured sea cucumber species in the Indo Pacific regions. Unfortunately, most of the sandfish farmer relies almost entirely on the wild captured sandfish. Therefore, hatchery seed production is now underway to meet the needs of aquaculture. Understanding the feeding regime is very crucial because it influenced the growth performance and affects the yield in the hatchery. In a factorial experiment, two microalgae species, Nannochloropsis sp. And Chaetoceros calcitrans at two different concentrations (2 × 10⁴ and 4 × 10⁴ cells ml^-1) were tested on sandfish larvae 2 days after hatching. The experiment was carried out for 2 weeks using plastic containers randomly arranged in a water bath (HDPE tank) with the temperature maintained at 29-30°C. The growth and survival of sandfish larvae were significantly affected by the feeding regime (p=0.015 and p=0.000), but not affected by the feed concentration (p=0.160 and p=0.512). The N2C feeding regime (2 days Nannochloropis  sp. + 12 days Chaetoceros sp.) at 4×10⁴ cells ml^-1 demonstrates the highest growth (38.09± 6.6%) while the highest survival was recorded in the larvae fed in a single species of Nannochloropsis sp. At 2×10⁴ cells ml^-1 (1.37±0.13%). The results also show that larval metamorphosis was very slow as there is no doliolaria stage recorded until the end of the experiment. This study suggests that feeding regime affects the larval development rate and thus will determine the success in the seed production of sandfish.