POPULATION-DENSITY AND GROWTH-RATE OF JUVENILE SOLE SOLEA-SOLEA (L)

The effect of population density on growth was studied for juvenile so le, Solea solea (L.), occupying a nursery ground on the North Wales co ast from 1988 to 1993. Between 1989 and 1992 growth rates were not sig nificantly different (0.54 to 0.57 mm.d(-1)), and by May of their firs t year of life the mean length of these cohorts ranged from 106.2 to 1 08.9 mm. In 1988 the growth rate was lower than that in the other year s, 0.42 mm.d(-1) It appeared that a severe bloom of the colonial alga Phaeocystis pouchetii may have been associated with the reduced growth rate of juvenile sole in 1988. The growth rates of these populations appeared to be unaffected by density which varied by a factor of five. The mechanism whereby juvenile fish populations may be able to adjust their distribution on the nursery ground to avoid density-dependent e ffects is discussed.