Effects of densities and salinities on growths and survival rates of planktonic larvae of bicolor pen shells (Pinna bicolor Gmelin, 1791)
Abstract
The study consisting of 2 experiments (15 days) and has been conducted from D-sharped larva to pediveliger larva of bicolor pen shells to evaluate the effects of different rearing densities and salinities on their growths and survival rates. The larvae were fed with fresh unicellular algae including Nannochloropsis oculata, Isochrysis galbana, Chaetoceros muelleri, Platymonas sp. The experiments were presented in 5 replications. In the density experiment, larvae were reared at 3 densities 1; 3; 5 larvae/ml. The results showed that the growth and survival rate of larvae were significantly different between the 3 stocking densities (P<0.05). The larvae reared at the density of 3 larvae/ml gave the highest growth (height reached 188.9±2.01 μm), the average growth rate (reached 7.98±0.145 μm/day) and survival rate of larvae was the highest (11.3%). In the second experiment, larvae were reared at 3 different salinities 26, 29, 32‰. The result showed that larvae at salinity of 29‰ had the highest growth rate and survival rate (8,18 ±0,06 μm/day and 11,3% respectively). Followed by salinity of 32‰, the growth rate was 7,98±0,09 μm/day and the survival rate was 10,5%. However, there was no statistically significant difference (P>0.05) about growth and survival between 29‰ and 32‰ salinities. The growth rate and survival were the lowest at 26‰ salinity (6.4±0.08 μm/day and 9%, respectively). So, the best stocking density was 3 larvae/ml, the most suitable salinity was 29-32‰.
