Development of a Type Zoning Model for Zululand Coral Reefs, Sodwana Bay, South Africa

Abstract

The coral patch reefs of the northern Natal coast are unique, being some of the most southerly in the world, and relatively unspoilt. Two-Mile Reef at Sodwana Bay has been used to develop a physiographic and biological zoning model for Zululand coral reefs which has been applied to other reefs in the region. The Zululand reefs are formed by a thin veneer of Indo-Pacific type corals which have colonized a submerged, late Pleistocene sandstone outcrop. The sedimentary facies beneath the corals were formed as a regressive coastal dune and beach sequence. Two-Mile Reef is a windward reef, and the zones are parallel to the north-northeast south-southwest reef/coast trend. Eight distinct zones can be recognized and differentiated on the basis of physiographic and biological characteristics. The reef fauna is dominated by an abundance of alcyonarian (soft) corals, which constitute 60 to 70% of the total oral fauna. The Two-Mile Reef zoning model has been successfully applied to larger reefs such as Red Sands Reef, and smaller patch reefs: Four-Mile and Seven-Mile Reefs which are in the same general area. Alcyonarian corals, physiographic and biological zoning, reef-base, southwestern Indo-Pacific faunal province, thin veneer reefs, three-dimensional reef