Effect of stocking density on growth performance of juvenile sea cucumber Holothuria tubulosa (Gmelin, 1788)

Abstract

Stock density is one among the most important factors in aquaculture that directly influences the growth of organisms; however, there is limited information about the effects of stocking density on growth performance of sea cucumber Holothuria tubulosa (Gmelin, 1788) that has a commercial potential and represents a new species for aquaculture. In this study, we investigated the effect of stocking densities on the growth performance of juvenile H. tubulosa (40.3 ± 3.34 g) in laboratory conditions. Stocking densities were selected as 6, 15 and 30 ind m−2 with total biomass 253.3 ± 0.18, 601.2 ± 0.11 and 1201.4 ± 0.15 g m−2 respectively. We monitored the growth by wet weights and calculated the growth performance through weight gain, growth rate, specific growth rate, relative weight gain, coefficients of variation and survival rate during 8 weeks of research period. We found that individual mean weight gain in 6 ind m−2 group was approximately 29.53 g while it was 3.03 g and −4.36 g for 15 ind and 30 ind m−2 groups respectively. Results have shown that the specific growth rate tends to decrease as the number of individuals in unit area increases. The final mean weight, growth rate, specific growth rate, relative weight gain and coefficients of variation were significantly different among treatment groups. In conclusion, a density of 6 ind m−2 is recommended for stocking juvenile H. tubulosa under rearing conditions. Stocking density of 15 ind m−2 is not favourable for long term as the growth rate is negligible where 30 ind m−2 should be avoided in tank-based rearing units.