A first description of the ichthyofauna of the Namibian Islands Marine Protected Area using baited remote underwater video systems

Data on the diversity, relative abundance and distribution of the ichthyofauna of Namibia's only marine protected area, the Namibian Islands Marine Protected Area (NIMPA), are limited and there is no active monitoring programme in place. Generating a baseline for these species is essential to inform management plans and policy. Baited remote underwater video system (BRUVs) surveys were conducted between 2022 and 2024 in the central eastern NIMPA. Data from 114 BRUVs samples, collected in water less than 45 m deep, were analysed in this study. Of the 17 fish species recorded, five were elasmobranchs, and three fish species - Galeorhinus galeus (CR), Notorynchus cepedianus (VU) and Argyrosomus inodorus (VU) - are classified as threatened on the IUCN Red List. The most frequently recorded elasmobranch, Haploblepharus pictus, was ubiquitous and typified all habitat types and depth categories. The most frequently recorded actinopterygian fish (Clinus spp.) was sighted at 37% of sites. Depth was an important predictor of fish species abundance and community composition, but habitat was not. Both ichthyofaunal relative abundance and diversity appeared lower than in similar surveys in neighbouring South Africa and other temperate waters. Future research should aim to identify the drivers of the observed patterns. The findings provide an important baseline for long-term monitoring of the NIMPA, necessary to better describe biodiversity and inform the development of management strategies.