Spawning and larval rearing of red sea urchin Salmacis bicolor (L. Agassiz and Desor, 1846;Echinodermata: Echinoidea)

Abstract

Gonads of sea urchin attract consumers due to its high nutritional value than any other seafood delicacies. Aquaculturists are also very keen on developing larval culture methods for large-scale cultivation. The present investigation systematically examined the larval rearing, development, survival and growth rate of Salmacis bicolor fed with various microalgal diets under laboratory condition. Fertilization rate was estimated as 95%. The blastula and gastrula stages attained at 8.25 h and 23.10 h post-fertilization. The 4 - armed pluteus larvae were formed with two well - developed post-oral arms at 44.20 h following post-fertilization. The 8 - armed pluteus attained at 9 days post fertilization. The competent larva with complete rudiment growth was developed on 25th days post - fertilization. Monodiet algal feed - Chaetoceros calcitrans and Dunaliella salina resulted medium (50.6 ± 2.7%) and low survival rate (36.8 ± 1.7%) of S. bicolor larvae. However, combination algal feed – Isochrysis galbana and Chaetoceros calcitrans has promoted high survival rate (68.3 ± 2.5%) which was significantly different between the mono and combination diet. From the observations of the study, combination diet could be adopted as an effective feed measure to promote the production of nutritionally valuable roes of S. bicolor.