The fecundity of long rough dabs in the Clyde Sea area

Abstract

The fecundity of 180 long rough dabs caught in the Clyde Sea Area from 1957 to 1961 ranged from 9700 eggs in a 12.2 cm fish to 251,300 eggs in one of 30.0 cm. The mean lengths of the fish in the samples each year were different so the comparisons between one year and another were based on the fecundity expected of a 22 cm fish. The differences between years were statistically significant, though successive years did not differ significantly when tested in pairs. The trends of increase and decrease in fecundity were very similar to those of the witch (and different from the plaice). It is suggested that, since witches and long rough dabs (in contrast to plaice) both prefer a muddy bottom, the fecundity variations from year to year might be caused by fluctuations in the abundance of some common food organisms.