Distribution of offshore demersal cartilaginous fish (Class Chondrichthyes) off the west coast of southern Africa, with notes on their systematics

Abstract

The geographic and the bathymetric distribution of offshore demersal cartilaginous fish off the west coast of southern Africa are reviewed. The results were collected during 12 cruises of F.R.S. Africana between 1986 and 1990. The area covered was between Walvis Bay (23°S, 14°E) and the Agulhas Bank west of Cape Agulhas (36°S, 20°E) over a depth range of 33–1 016 m. In all, 55 species of cartilaginous fish were collected, including 32 sharks, 17 rays and six chimaeras, on 869 stations and representing 3 092 station records. Computer-generated maps and station lists are presented for the species in the sample, and the distribution records, including records from the literature, are reviewed and discussed for these species and 12 more demersal species not collected during the survey. The survey revealed many range extensions for described species. West Coast demersal cartilaginous fish show zonation by depth and latitude, and groups of species with similar depth and latitudinal distributions were apparent. These groups are defined and discussed, along with summer-winter distributional differences, aggregations of records, sympatry and allopatry in related species, and relative diversity over 50-m depth increments and one-degree latitudinal bands.