South Africa's mainland submarine canyons

This spatial vector layer represents a map of South Africa’s mainland submarine canyons. Its creation was motivated by the need for ongoing improvements to South Africa’s Marine Ecosystem Map (MEM) and the substantial improvements in the visibility of submarine canyon features provided by the creation of an updated bathymetry map for South Africa (https://catalogue.saeon.ac.za/records/10.15493/SANBI.220424; Manikam et al. 2024). The map was prepared using South Africa’s 100-m resolution bathymetry dataset (Manikam et al. 2024), additional high-resolution multibeam bathymetry, seafloor variables derived from the bathymetry data, and expert consultation. Spatial delineation was primarily undertaken in QGIS, while R scripts were used for data preparation, derivation of bathymetric variables, and canyon attribute calculation. The methods are documented in the technical report served alongside this dataset and in the canyons GitLab project (https://gitlab.com/marine-map/geomorphology/canyon). Previously, 39 canyon features were mapped in the 2018 MEM (https://bgis.sanbi.org/SpatialDataset/Detail/2681). This dataset increases the number of canyon features to 120 and includes a suite of canyon feature attributes. The dataset strengthens our understanding of canyon distribution, classification, morphology and ecological relevance. This product will support national biodiversity assessments, marine spatial planning, and ecosystem protection and management, with future updates planned as improved bathymetric data becomes available.