Subtropical demersal fish communities on soft sediments in the KwaZulu-Natal Bight, South Africa

Abstract

The project entitled Ecosystem Processes in the KwaZulu-Natal Bight, part of the African Coelacanth Ecosystem Programme (ACEP), enabled the description of demersal fish communities over soft sediments, including from some areas that have rarely been explored in the subtropical waters of the east coast of South Africa. A total of 165 fish taxa from 78 families were caught, and were dominated by the Sparidae (five species), Triglidae (four species), Acropomatidae (three species), Macrouridae (eight species), Chlorophthalmidae (one species), Paralichthyidae (three species) and Sciaenidae (six species), which together contributed 75% and almost 60% to numbers and weight, respectively. The most ubiquitous species were Chlorophthalmus punctatus and Pagellus natalensis. Species composition was structured mainly by depth, and proximity to the Thukela River, the latter being particularly influential on the adjacent Thukela Bank that harbours a unique community. There are close affinities between KZN Bight soft-sediment fish communities and those off Western Australia, and particularly with communities from East Africa. The unique nature of fish communities off the Thukela River is part-motivation towards the establishment of a large marine protected area in the northern part of the KZN Bight, which is increasingly the focus of disruptions such as impoundments and mining.