CORRESPONDENCE BETWEEN FOOD AVAILABILITY AND GROWTH OF A PLANKTIVOROUS TEMPERATE REEF FISH

Although food availability generally has not been considered to be an important influence on the demography of reef fishes, a few studies ha ve indicated that it can affect individual growth and the local abunda nce of some species. We examined the relationship between food availab ility and growth of the kelp perch, Brachyistius frenatus Gill, a plan ktivorous temperate reef fish. Among sites, there was a high degree of concordance in the rank abundance of planktonic taxa, even though pre y biomass differed significantly. The growth of juvenile kelp perch am ong sites was positively and linearly related to prey biomass, suggest ing that food can be a limiting resource for this fish over a wide ran ge of prey abundance. Young kelp perch are closely associated with the giant kelp, Macrocystis pyrifera (L.) C.Ag. and appear to be restrict ed in their movements to reefs in which they were born. Therefore, the re may be important consequences of differential food availability in that differences in the rate of delivery of zooplankton to these reefs , further affected by the physical structure of Macrocystis, may subst antially influence juvenile growth rates and other demographic charact eristics of kelp perch populations.