Effect of salinity, light intensity and tank size on larval survival rate of shoemaker rabbitfish Siganus sutor (Valenciennes, 1835)

The hatching rate and larval survival of shoemaker rabbit fish Siganus sutor at different environmental conditions were surveyed in 2014. Adult and sub adult fishes were captured from coastal waters of Lavan Island, Hormozgan Province, Iran and were transported to Persian Gulf and Oman Sea Ecological Research Center, and reared until reproduction season. Induced spawning took place using HCG hormone (500 IU kg-1 body weight), during April – May when the environmental temperature was reached around 26-28 oC. Eggs were stocked at a density of 25 Eggs L-1 in different tank size (40, 300 and 2400 L, tanks) to determine the effects of tank size on eggs,  hatching rate  and survival of fish larvae. Three  salinities (25, 30 and 37 ppt), and three light intensity (10000, 5000, and 2000 lux) were examined  in 300L tanks and survival rates of larvae were assessed on days 3, 5, 7, 10, 15 and 20 of culturing period. There was no significant difference between hatching rate of S. sutor eggs, in various hatching tanks (p>0.05), but survival rates of larvae was significantly higher in 300 Land 2400 L tanks (p<0.05), the survival rate of S. sutor larvae was significantly higher in 30 ppt salinity than the others (p<0.05). There was no any significant difference between survival rate of larvae in salinity 25 and 37 ppt (p>0.05). The survival rate of larvae was significantly higher in 2000 lux intensity of light (p<0.05), under intense light (5000 and 10000 lux), the mortality of larvae was increased.