VARIATION IN STRUCTURE AND BIOMASS OF KELP COMMUNITIES ALONG THE SOUTH-WEST CAPE COAST

Summary

Transects across six kelp beds located between Cape Agulhas and Saldanha Bay are surveyed and the fauna and flora quantified in terms of energy units. Numerical analysis and information statistic tests are employed to identify areas of similarity and their characteristic species. When data from all the transects are pooled and similarly tested there is a separation of plant-dominated inshore zones from offshore stations, which are densely populated by animals. The more southerly transects tend to have higher overall standing crops of kelp—a feature which can be attributed to the greater water clarity in this area. Both mussels and rock lobsters show the reverse trend, being largely replaced by a sponge-dominated community in the south. Calculations of the plant to animal ratios at each site average only 1,27:1, suggesting that the fauna relies largely on nutritional sources other than attached algae. Standing crop figures are used to calculate the total tonnage of kelp between Cape Point and Saldanha Bay and its annual production of detritus. Standing crop figures for each transect and energy content conversion tables are listed as appendices.