GROWTH, SURVIVAL AND SETTLEMENT OF ASIAN GREEN MUSSEL Perna viridis EYESPOT LARVAE AT DIFFERENT STOCKING DENSITIES IN DOWN-WELLING SYSTEM
Micro - nursery system consists of down - welling and upwelling systems which can be effectively utilized for mass seed production of bivalve seed. In the present study down welling system of 2000 l capacity with 4 compartments is used. System consists of 32 wells made PVC pipes with 150 µ bottom mesh. Wells were stocked with green mussel, Perna viridis eyespot larvae in different stocking densities and reared for the period of 30 days to find out optimum stocking density, growth and survival. Eye spot larvae were stocked in 150 µ mesh with 50,000, 1.0 lakh , 1.5 lakh , 2.0 lakh, 2.5 lakh and 3.0 lakh larvae in triplicates. Larvae were fed with algal mixture (20 to 80 litres progressively increasing during the period of rearing) Isochrysis galbana and Chaetoceros calcitrans with the cell density of 2.91 - 3.08 x 106 cells /ml for entire culture period. From the present study, it was observed that the percentage survival for the stocking density of 50,000, 1 lakh and 1.5 lakh , 2.0 lakh 2.5 lakh and 3.0 lakh is 23.6 , 30.4, 19.3, 18.9, 21.4 and 19.2 and growth rate is 2.7 mm, 2.76mm, 3.19 mm, 2.26 mm, 2.4 and 2.5mm . The results were statistically tested and presented in the paper.
