Effect of salinity on growth and survival of king scallop spat ( Pecten maximus)

Abstract

Hatchery-reared king scallop ( Pecten maximus L.) spat were held at a range of salinities (26–30 and 30–35 psu) at temperatures between 9 and 21 °C. Mean growth rate (as increase in shell height), food cell clearance rate and condition index (as ratio of dry meat weight to dry shell weight) were similar in the salinity range 30–35 psu at all temperatures. Growth rate was significantly lower at 26 psu than at 28–30 psu at 13–21 °C. Food cell clearance rates were always lower at 26 psu than at 30 psu, but the difference was only significant at 13 °C. Condition index was not affected by salinity in the range 26–30 psu at any of the temperatures tested. In experiments in which scallop spat were exposed to low salinity (20–25 psu) for short periods (up to 6 h day −1 over 3 days) at ambient temperature (7.2–18.7 °C). The subsequent growth rate was usually significantly lower at 20-psu exposure, and this salinity gave high mortality in one experiment at 10 °C. Reductions in growth rate were temporary, and growth recovered to control (ambient salinity) rates within 10 days after exposure.