Evaluating the Efficacy of a Marine Reserve for Threatened and Endemic Sharks Off South Africa

The coastal waters of South Africa are habitat to a diverse composition of sharks, many of which are endemic to the region and/or classified by the International Union for Conservation of Nature Red List as threatened or data deficient. As fishing pressure in the nation’s waters persists, this region has become a research and conservation priority for elasmobranch fishes. Within the Western Cape, the De Hoop Marine Protected Area occupies approximately 288 km² of coastal water and is considered one of South Africa’s flagship marine protected areas (MPAs). With its no-take status, the MPA provides protection for sharks within its confines; however, they are susceptible to capture by demersal shark longline vessels that target its boundaries. Baited remote underwater video surveys (BRUVS) were used to evaluate relative abundance of sharks at the community assemblage level and passive acoustic telemetry explored habitat-use patterns for six key species. When combined, these approaches revealed insights into the De Hoop MPA’s efficacy for the protection of local endemic and threatened species. Focal species included the endemic puffadder shyshark (Haploblepharus edwardsii), dark shyshark (Haploblepharus pictus), leopard catshark (Poroderma pantherinum), spotted gully shark (Triakis megalopterus), and pyjama catshark (Poroderma africanum) and juveniles of the threatened species, smooth hammerhead (Sphryna zygaena). Results revealed that relative abundance of sharks on a community assemblage level was significantly greater inside the MPA, supporting the hypothesis that sharks would be more abundant inside the MPA than outside of its boundaries. Additionally, relative abundance inside the MPA significantly increased on BRUVS samples that were deployed farther from the reserve’s exposed boundaries. Residency analysis of key species found elevated residency outside De Hoop’s borders and on the shark longline fishery-targeted Eastern Boundary of the MPA. Taken together, these results show that while the MPA is effective at containing increased shark abundance, the Eastern Boundary and adjacent unprotected waters are important for shark habitat utilization. These complementary findings demonstrate the utility of MPAs for protecting conservation priority shark species and reveal an opportunity to alter management for more sufficient protection.