Salinity stress on embryos and early larval stages of the pomfret Pampus punctatissimus

The pomfret, Pampus punctatissimus, is an important fisheries resource in China and a valuable and highly esteemed fish species on the Chinese market. It is currently being evaluated as a candidate for mariculture to meet increasing demand. To better understand the tolerance of this species to varying environmental salinity at early developmental stages, the effects of salinity on egg buoyancy, embryo development, egg hatching, and morphology of early larva were determined. Egg neutral buoyancy was seen at 25–29‰ salinity. Below 20‰ salinity, all eggs sank, and above 30‰ salinity, all floated on the surface. Time to first hatching was 24–28 h at 26–28 °C in all salinities, but eggs/embryos exposed to salinities ≤ 10‰ died. Hatching rates decrease substantially at salinities ≤ 25‰ and ≥ 40‰, and the highest hatching rate (68.2%) occurred at 29–32‰. The percentage of abnormalities of newly hatched larvae was lowest at 29–30‰ salinity, lower (≤ 25‰) and higher (≥ 40‰) salinities resulted in significantly higher percentage of abnormalities. The results on buoyancy, hatching rate, and early larval deformity, indicate that fertilized eggs of P. punctatissimus only develop well in a narrow range of salinities. We conclude that the optimal salinity for successful development of fertilized eggs lies between 29 and 32‰ where neutral egg buoyancy, highest egg hatching rate, and lowest incidence of abnormality rate was observed.