Survival and growth performance of sub-adult sandfish Holothuria scabra (Jaeger, 1833) in tanks with different supplemental feeds

Abstract

Sandfish (Holothuria scabra Jaeger, 1833) is one of the most valuable sea cucumbers in local and international markets. Although listed as an endangered species, it is among the regularly harvested marine resources in Palawan, Philippines. To continue the trade of sandfish without harvesting from the wild, this study initially ventured into producing seed stocks. However, broodstocks were scarce, only sub-adults were available, and they needed to grow into broodstocks. This study evaluated the survival and growth performance of sub-adult sandfish when fed with soya bean powder (Treatment 1/T₁), rice bran (Treatment 2/T₂), and powdered seagrass leaves (Treatment 3/T₃). Each treatment and control (no supplemental feeding) had three replicates with three sandfish having 59.55 ± 10.24 g mean weight and 9.74 ± 0.98 cm mean length. The samples were cultured in aerated plastic tanks (63.5 cm × 45.72 cm × 35.56 cm) with a 10 cm layer of sandy-muddy sediment filled with 40 L seawater, which was changed twice a day. Results showed 100% survival in T₃ and control, 66% in T₁, and 0% in T₂. The mean weight and length were stable in the first two weeks of culture in all treatments and control, but the latter declined during the 3^rd and 4^th weeks of culture (P < 0.05). Such was attributed to the drop in salinity during the 3^rd week. Nevertheless, seagrass powder and soya beans appeared to help maintain the growth and tolerance to stress of sub-adult sandfish while unprocessed rice bran was detrimental to the health of sub-adult sandfish and caused mortality before the end of the culture period.