SPATIAL VARIABILITY IN THE MUDPRAWN UPOGEBIA AFRICANA ON THE SOUTH-EAST COAST OF SOUTH AFRICA

Abstract

A nested sampling design was used to examine the variability in density, biomass, sex ratio and size of the estuarine mudprawn Upogebia africana in six estuaries on the south-east coast of South Africa. The objectives were to test the general hypothesis that there is variability in these variables at the scales of regions, estuaries, banks and tidal levels, and then to determine at which spatial scales these were most variable. Nested analyses of variance revealed significant differences in the mean size of mudprawns at the scale of regions, in mean size and sex ratio at the scale of banks, and in all four variables at the scale of tidal levels. The greatest variability in all four variables was at the smallest spatial scale examined. The likely causes of this spatial variability are discussed.

Afr. J. mar. Sci. 25: 275–282