The influence of site, season and day of the week on exploitation of rocky intertidal biota in central Transkei, South Africa

Abstract

Temporal and spatial variations in the pattern and intensity of exploitative use of rocky shores in the densely populated central Transkei region of the south-east coast of South Africa are described. Surveys of intertidal exploiters and their catches were conducted simultaneously on five randomly selected weekdays and weekends per season between June 1995 and June 1996 at Umtata Mouth, Mngcibe and Lwandile. Three-way ANOVAs were used to assess the influence of site, season and day of the week (weekday or weekend) on the density of the three major groups of exploiters: shellfish-gatherers, seaweed-harvesters and bait-collectors, and on the offtake by shellfish-gatherers. The densities of shellfish-gatherers or seaweed-harvesters did not differ between sites, but there were marked differences in the density of bait-collectors and the quantity of organisms removed by shellfish-gatherers. The numbers in all exploiter groups were lowest in winter, because of factors such as inaccessibility caused by rough seas, poor quality of the preferred shellfish and a clash with such agricultural activities as harvesting of maize. The densities of adult shellfish-gatherers and shellfish offtake were both significantly higher on weekdays than at weekends. However, more children gathered shellfish during the weekends and in summer, perhaps attributable to the closure of schools.

Keywords: exploitation, rocky shores, temporal/spatial variation, Transkei

African Journal of Marine Science 2002, 24: 57–64