Effects of rotifer densities on larval performance of spotted scat (Scatophagus argus)

Abstract

This study is aimed to determine the optimal rotifer feeding density for larviculture of spotted scat fish (Scatophagus argus). The experiment was randomly set up in triplicate with 5 treatments including 5, 10, 15, 20 and 25 rotifers/mL. The fish larvae with the initial body length and depth at 2,343 ± 110 µm and 812 ± 85µm, respectively, were stocked in 250-L tanks at 10 larva/L of density and 25‰ of salinity. After 21 days of rearing, the results showed that the larval growth were at 243 – 330 µm/day of DLG and 5.50 – 6.70 %/day of SGRL; 131 –204 µm/day of DDG and 7.20 – 8.93 %/day of SGRD, but no significant difference in larval growth performance was recorded among treatments (p>0.05). However, the highest survival rate of fish larvae (35.4-48.1%) was recorded in the treatments fed 5 and 10 rotifers/mL and was significantly higher than other treatments (p<0.05). The data demonstrated that spotted scat larvae fed effectively across as wide range of rotifer densities and the range at 5-10 rotifers/mL were suggested for the husbandry practices.