Original Articles

An assessment of the role of the sand shark Rhinobatos annulatus as a predator in Langebaan Lagoon

Published in: South African Journal of Marine Science
Volume 7, issue 1, 1988 , pages: 153–159
DOI: 10.2989/025776188784379125

Abstract

The possible impact of predation on benthic invertebrates by the sand shark Rhinobatos annulatus in Langebaan Lagoon was investigated. Studies on the population dynamics and the feeding biology of the sand sharks indicated temporal and spatial changes in the intensity of predation. Temporal changes were seasonal, numbers and biomass increasing during summer. The sand sharks were concentrated in specific areas of the lagoon, and their distribution appeared to be correlated with that of prey biomass. Crustaceans constituted the major portion (88,12%) of the diet. Calculations suggest that 26–77 per cent of the annual invertebrate production is consumed by sand sharks, so it is evident that R. annulatus has a substantial impact on the macrofauna and thereby plays an important role as a predator in Langebaan Lagoon.

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