First survey of fishes in the Betty’s Bay Marine Protected Area along South Africa’s temperate south-west coast

Abstract

This first survey of fish in the Betty’s Bay Marine Protected Area (MPA), on the south coast of South Africa, was conducted using baited remote underwater video systems (BRUVs). A total of 58 deployments recorded 42 species in 20 km², including reef, kelp and sand habitats in protected and exploited zones, at between 5 and 40 m depth. Chondrichthyans accounted for 28% of diversity. Teleost diversity was dominated by Sparidae, Cheilodactylidae, Sciaenidae and Ariidae. Diversity (H′) was highest in kelp and lowest over sand. Species composition differed among habitat and depths, but protection had no effect. Among four commercial species, only Pachymetopon blochii responded positively to protection. The apparent failure of protection may attest to poor compliance, but an investigation into fish size might show an effect. Many species were detected at the western extreme of their range. Diversity in Betty’s Bay was predictably lower than in the more eastward Stilbaai MPA, but also lower than in the westward Table Mountain National Park MPA. Fish diversity did not follow a linear increase eastwards from Cape Point. Betty’s Bay includes the most easterly protected kelp forests and contains seven species not recorded in the other two areas, and is therefore an important element in the MPA network.

Keywords: BRUVs, fish survey, MPA, species composition, species diversity