Overfishing and climate change elevate extinction risk of endemic sharks and rays in the southwest Indian Ocean hotspot

Here, we summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the southwest Indian Ocean and adjacent waters (SWIO+, Namibia to Kenya, including SWIO islands). This region is a hotspot of endemic and evolutionarily distinct sharks and rays. Nearly one-fifth (n = 13 of 70, 18.6%) of endemic sharks and rays are threatened, of these: one is Critically Endangered, five are Endangered, and seven are Vulnerable. A further seven (10.0%) are Near Threatened, 33 (47.1%) are Least Concern, and 17 (24.3%) are Data Deficient. While the primary threat is overfishing, there are the first signs that climate change is contributing to elevated extinction risk through habitat reduction and inshore distributional shifts. By backcasting their status, few endemic species were threatened in 1980, but this changed soon after the emergence of targeted shark and ray fisheries. South Africa has the highest national conservation responsibility, followed by Mozambique and Madagascar. Yet, while fisheries management and enforcement have improved in South Africa over recent decades, substantial improvements are urgently needed elsewhere. To avoid extinction and ensure robust populations of the region's endemic sharks and rays and maintain ecosystem functionality, there is an urgent need for the strict protection of Critically Endangered and Endangered species and sustainable management of Vulnerable, Near Threatened, and Least Concern species, underpinned by species-level data collection and reduction of incidental catch.

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Publication Details

Journal
PLoS ONE
Published
2024-09-05
DOI
https://doi.org/10.1371/journal.pone.0306813
Citations
17
Primary Topic
Ichthyology and Marine Biology
Type
article
Field-Weighted Citation Impact
11.06

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article

Overfishing and climate change elevate extinction risk of endemic sharks and rays in the southwest Indian Ocean hotspot

Nathan Pacoureau, Jessica Cheok, Nicholas K. Dulvy, R. W. Leslie et al.
17 citations
PLoS ONE
Ichthyology and Marine Biology
11.06
article

Overfishing and climate change elevate extinction risk of endemic sharks and rays in the southwest Indian Ocean hotspot

Nathan Pacoureau, Jessica Cheok, Nicholas K. Dulvy, R. W. Leslie, RH Bennett, David A. Ebert, Rima W. Jabado, Caroline M. Pollock, Baraka Kuguru, Melita Samoilys, Katie S. Gledhill, Peter M. Kyne, Meaghen E. McCord, S.T. Fennessy, Henning Winker, Cassandra L. Rigby, Riley A. Pollom, Katelyn B. Herman, Charlene da Silva, Stela Fernando
article en
17 citations

Abstract

Here, we summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the southwest Indian Ocean and adjacent waters (SWIO+, Namibia to Kenya, including SWIO islands). This region is a hotspot of endemic and evolutionarily distinct sharks and rays. Nearly one-fifth (n = 13 of 70, 18.6%) of endemic sharks and rays are threatened, of these: one is Critically Endangered, five are Endangered, and seven are Vulnerable. A further seven (10.0%) are Near Threatened, 33 (47.1%) are Least Concern, and 17 (24.3%) are Data Deficient. While the primary threat is overfishing, there are the first signs that climate change is contributing to elevated extinction risk through habitat reduction and inshore distributional shifts. By backcasting their status, few endemic species were threatened in 1980, but this changed soon after the emergence of targeted shark and ray fisheries. South Africa has the highest national conservation responsibility, followed by Mozambique and Madagascar. Yet, while fisheries management and enforcement have improved in South Africa over recent decades, substantial improvements are urgently needed elsewhere. To avoid extinction and ensure robust populations of the region's endemic sharks and rays and maintain ecosystem functionality, there is an urgent need for the strict protection of Critically Endangered and Endangered species and sustainable management of Vulnerable, Near Threatened, and Least Concern species, underpinned by species-level data collection and reduction of incidental catch.

PLoS ONEVol. 19(9)
University of Technology Sydney (AU), Canadian Parks and Wilderness Society (CA), Department of Agriculture, Land Reform and Rural Development (ZA), Simon Fraser University (CA), Stellenbosch University (ZA), Florida Aquarium (US), Charles Darwin University (AU), Tanzania Fisheries Research Institute (TZ), South African Association for Marine Biological Research (ZA), International Union for Conservation of Nature (United Kingdom) (GB), Elasmo Project (AE), Coastal Oceans Research and Development in the Indian Ocean (KE), National Directorate of Geology (MZ), Seattle Aquarium (US), Endangered Wildlife Trust (ZA), South African Institute for Aquatic Biodiversity (ZA), James Cook University (AU), Moss Landing Marine Laboratories (US)
Australian Government, National Research Foundation, University of Cape Town, Save Our Seas Foundation, Department of Agriculture, Forestry and Fisheries, South African Institute for Aquatic Biodiversity, Department of Forestry, Fisheries and the Environment, Centre for Marine Living Resources and Ecology, Ministry of Earth Sciences
Openalex Percentile: Top 1%
Ichthyology and Marine Biology
11.06
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