Taxonomy and diversity of the sponge fauna from the Agulhas bank hard reef complex off the South African south coast

Abstract

Hard benthic reefs are increasingly known as highly diverse biodiversity ecosystems where sponges constitute a significant proportion of inhabitants. Nearly 60% of the seabed over the inner and outer shelf on the Agulhas Bank comprises hard substrata, and in combination with the convergence of the cold Benguela and the warm Agulhas Currents serves to create a nutrient rich zone supporting multiple fish nurseries. Here we provide the first information on hard benthic reef habitats on the subphotic zone of the Agulhas Bank complex marine protected area, which include Alphard Banks, 72 Mile Reef and 45 Mile Reef, as well as the shallow reefs which include 12 Mile Reef, 6 Mile Reef, 7 Mile Reef, Marthas Reef and inshore reefs within the Tsitsikamma marine protected area. The aim is to provide baseline data on the sponge fauna by identifying species and describing the biodiversity of these hard reefs between the depths 10–200 m on the south coast of South Africa.