Effects of Light Intensity On Survival Rate and Larval Development of Blue Swimming Crab, Portunus pelagicus Under Laboratory Conditions
A 3-week experiment was carried out to investigate the effects of light intensity on survival rate and larval development of the blue swimming crab, Portunus pelagicus under culture conditions. Four light intensities (1000 – 1500, 2000 – 2500, 3000 – 3500 and 4000 – 4500 lx) were compared in triplicate. The results showed that the first zoeal stages reared under 1000 – 1500 lx did not reach the third zoeal stages; all larvae died 14 days, after hatching. At the end of the experiment,
27.78±3.60% of the first zoeal larvae under 3000-3500 lx were metamorphosed into the first crab stage in contrast to only 15.56±2.72% of those cultured under 4000-4500 lx (P<0.05). In all of this intensity, it took
4.67 to 5.33 days for the intermolt period and was not statistically significant (P>0.05).