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 have indicated that it can affect individual growth and the local abundance of some species. We examined the relationship between food availability and growth of the kelp perch, Brachyistius frenatus Gill, a planktivorous temperate reef fish. Among sites, there was a high degree of concordance in the rank abundance of planktonic taxa, even though prey biomass differed significantly. The growth of juvenile kelp perch among sites was positively and linearly related to prey biomass, suggesting that food can be a limiting resource for this fish over a wide range of prey abundance. Young kelp perch are closely associated with the giant kelp, Macrocystis pyrifera (L.) C.Ag. and appear to be restricted in their movements to reefs in which they were born. Therefore, there 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 substantially influence juvenile growth rates and other demographic characteristics of kelp perch populations.