Effect of salinity, light intensity and tank size on larval survival rate of shoemaker rabbitfish Siganus sutor (Valenciennes, ۱۸۳۵)

The hatching rate and larval survival of shoemaker rabbit fish Siganus sutor at different environmental conditions were surveyed in ۲۰۱۴. 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 (۵۰۰ IU kg-۱ body weight), during April – May when the environmental temperature was reached around ۲۶-۲۸ oC. Eggs were stocked at a density of ۲۵ Eggs L-۱ in different tank size (۴۰, ۳۰۰ and ۲۴۰۰ L, tanks) to determine the effects of tank size on eggs,  hatching rate  and survival of fish larvae. Three  salinities (۲۵, ۳۰ and ۳۷ ppt), and three light intensity (۱۰۰۰۰, ۵۰۰۰, and ۲۰۰۰ lux) were examined  in ۳۰۰L tanks and survival rates of larvae were assessed on days ۳, ۵, ۷, ۱۰, ۱۵ and ۲۰ of culturing period. There was no significant difference between hatching rate of S. sutor eggs, in various hatching tanks (p>۰.۰۵), but survival rates of larvae was significantly higher in ۳۰۰ Land ۲۴۰۰ L tanks (p<۰.۰۵), the survival rate of S. sutor larvae was significantly higher in ۳۰ ppt salinity than the others (p<۰.۰۵). There was no any significant difference between survival rate of larvae in salinity ۲۵ and ۳۷ ppt (p>۰.۰۵). The survival rate of larvae was significantly higher in ۲۰۰۰ lux intensity of light (p<۰.۰۵), under intense light (۵۰۰۰ and ۱۰۰۰۰ lux), the mortality of larvae was increased.

کلیدواژه ها:

Rabbitfish ، Salinity ، Light intensity ، Survival rate ، Hatching rate ، Siganus sutor ، Persian Gulf