Effect of different levels of salinity on growth performance and survival rate of polychaete Perinereis nuntia

The vital role of polychaete Perinereis nuntia in Penaeid shrimp sexual maturation shows the Importance of biotechniques and economical culture of this species in aquaculture. In the present study, the effect of four different salinity treatments, 0, 10, 20 and 35 ppt on growth and survival rate of Perinereis nuntia was examined in a three months experimental period. A number of 480 polychaetes with average initial weight of 0.409 ± 0.020 g were cultured with Enteromorpha green algae Ulva(Enteromorpha) flexuosa diets for 12 weeks. The results indicated significant effect of water salinity on final weight and survival rate of P. nuntia. Final weight and survival rate of polychaetes cultured at 20 and 35 ppt, were significantly higher than polychaetes cultured at 10 ppt (P<0.05). All polychaetes cultured at 0 ppt (fresh water) died. The results of the present study showed that P.nuntia has the optimal growth and survival rate at 20 and 30 ppt. therefore; depending on the condition of hatcheries and availability of sea water, its recommended that cultured at 20-30 ppt this species.