South Africa’s newly approved marine protected areas have increased the protected modelled habitat of nine odontocete species

Abstract

Marine protected areas (MPAs) are important for the preservation of ecosystem functioning, ecosystem services, resilience and biodiversity around the world. In South Africa, the role of MPAs in the protection of cetaceans is poorly understood, a knowledge gap that may affect management decisions and future cetacean conservation. Here, we used presence data of 9 odontocete species (namely southern bottlenose whale Hyperoodon planifrons, common dolphin Delphinus delphis, dusky dolphin Lagenorhynchus obscurus, false killer whale Pseudorca crassidens, Indo-Pacific humpback dolphin Sousa chinensis, Heaviside’s dolphin Cephalorhynchus heavisidii, killer whale Orcinus orca, Risso’s dolphin Grampus griseus and Indo-Pacific bottlenose dolphin Tursiops aduncus) to predict their distribution in the South African exclusive economic zone (EEZ) using ensemble models. The data were collected from various opportunistic, historical and scientific records spanning the period 1957-2014. Up to 9 predictor variables (sea surface temperature, chlorophyll a concentration, salinity, bathymetry, distance to shore, bottom slope, eastward and northward sea water velocity and bioregion) were used in the ensemble model to predict the distributions for each odontocete species. Model results suggest that some of the species’ preferred habitats are partially (i.e. <5% of the distribution) protected by the established MPAs, but the protection area does increase with the recently approved MPAs. This study provides a baseline for the distribution of the 9 odontocete species in relation to the MPAs, which could facilitate the protection and management of these species in the region and help identify important marine mammal areas.