The influence of salinity on growth indices and survival rate of Grass carp (Ctenopharyngodon idella) fry

The aim of this study was to investigate the influence of salinity on growth indices and survival rate of Grass carp (Ctenopharyngodon idella). This research was done in the laboratory of Sari Agricultural Sciences and Natural Resourcesuniversity during 28 days. 140 Grass carp fry at beginning of the first feeding (mean weight and length 1.59 ± 0.32, 4.72±0.38, respectively) were investigated in 4 salinity treatments (salinity 0, 2, 4 and 6 ppt) and 3 replicates. Culture temperature was 27±1˚C. The highest survival rate was obtained in salinity 0, 4 ppt and the lowest survival rate was observed in salinity 6 ppt. Weight gain percent was remarkably higher in salinity 0 ppt than other treatments (p<0.05). SGR was maximum and minimum in salinity 0 and 2 ppt, respectively. Just salinity 4 ppt had significant higher measurement of condition factor while other treatments didn't have any significant differences. Overall, this research recommends that Grass carp fry culture well in water with salinity lower than 4 ppt.