A benthic survey of the rocky reefs off Pondoland, South Africa

Abstract

A subtidal marine biodiversity survey was carried out on shallow reefs (–1m to –30m) in the proclaimed Pondoland Marine Protected Area between Port Edward and Port St Johns, South Africa. A total of 26 benthic reef transects was undertaken involving the capture and processing of 1 042 photographic images of the reef benthos. Results of the benthic survey showed a shift from algal-dominated reefs in the north to suspensionfeeder-dominated reefs in the south, probably on account of turbidity (reduced sunlight penetration) and high nutrient levels from riverine input. A similar shift was found with increasing reef depth with algae dominating shallower reefs and suspension-feeding communities dominating deeper reefs. Non-exhaustive inventories were compiled of dominant organisms, including algae, sponges, other invertebrates and fish. The results of this survey confirm that the Pondoland region has a rich marine biodiversity and is situated within a unique transition zone between subtropical and warm temperate waters. It is imperative that this rich biodiversity, coupled with the aesthetic beauty of the Pondoland coastline, be adequately zoned for protection within the proclaimed marine protected area.

Keywords: benthic fauna and flora; biodiversity survey; marine geographic information system (GIS); marine protected area (MPA); Pondoland coast; subtropical reef communities

African Journal of Marine Science 2007, 29(1): 65–77