Aspects of the biology of Caffrogobius Caffer (Günter) (Pisces : Teleostei : Gobiidae) in the Eastern Cape

Abstract

Several strategies used by the gobiid fish Caffrogobius caffer enabling it to colonise the harsh intertidal environment in the eastern Cape were studied. Q. caffer is opportunistic in its use of available food resources and feeds throughout the day with a slight tendency towards crepuscular peaks of feeding activity. The system of space utilisation used by C. caffer is so organised that all individuals of the population have access to patchily distributed food resources. Current velocities occurring over high tide limit the movements of Qo caffer and interpool movements occur only during the initial stages of a rising tide and in the final stages of an ebbing tide when the current velocities are below the tolerance limit of Q. caffer. The epifauna associated with the alga Ulva rigida, which forms an important constituent of the diet of the intermediate size classes of Q. caffer, was examined and it appears that this epifauna is an important source of food to Q. caffer. This report presents the results of the first detailed study of the biology of an intertidal fish in southern Africa.