Influences of Salinity on Hatching and Zoeal Growth of a Catadromous Crab, Eriocheir japonicus

Abstract

Percentage of ovigerous Eriocheir japonicus females which released larvae, as well as survival and growth of the larvae, were observed at different salinities to estimate an appropriate salinity for the larval growth. Percentages of ovigerous females which released larvae, were 99, 97, 76, 17, and 0% at 34, 24, 12, 6, and 0 psu salinity, respectively. Higher survival rates than 50% were obtained in salinity combinations above 24 psu both for stock culture of ovigerous females and for larval rearing. Period of zoeal larvae was also shorter in salinity combinations above 24 psu both for stock culture of ovigerous females and for larval rearing than other combinations. Rearing salinity affected larval development more intensively than the salinity for stock culture of ovigerous females. Salinity range from 35 psu (normal sea water) to 25 psu is recommended for both stock culture of ovigerous females and rearing of the zoeal larva.