Seasonal patterns in a temperate intertidal fish community on the west coast of South Africa

Seasonality was investigated in an intertidal ichthyofaunal community on the west coast of South Africa. Fishes were collected monthly from 12 to 16 intertidal pools between May 1992 and May 1993, using the ichthyocide rotenone. On each occasion sampling effort was divided equally between four biologically determined shore zones, namely the cochlear, lower and upper balanoid and littorina zones. A total of 5 409 fishes belonging to 20 species and five families was collected. All fishes were intertidal residents. No seasonal trend could be found in the total density of fishes during the year, the densities of individual species, species diversity or evenness. Thus species composition remained stable over the year. The proportion of mature individuals of each species decreased in summer as a result of recruitment of juveniles at this time. This almost complete lack of seasonality was attributed to the absence of transient species from this community.