Variations in plaice fecundity in the clyde area

Abstract

The fecundity of Clyde plaice, which has been studied from 1956 to 1961, has not been found to change as the breeding season approaches. However, there was a marked fecundity change from about 137 thousand eggs to around 161 thousand after 1957. The fecundity of all age groups increased and this appears to be associated with the fishing intensity and so the population density. Heavy fishing leads to fewer fish with the same food supply which in turn allows higher fecundity. The changes in fecundity therefore seem to be part of a density dependent population regulating mechanism.