Nearly two-thirds of coral reef shark and ray species worldwide are threatened with extinction, reports a study in Nature Communications. The results suggest that the extinction risk of coral reef sharks and rays, as a percentage of threatened species, is almost double that of all 1,199 known shark and ray species. The findings highlight the need for immediate conservation action for these species through local protections, fisheries management and enforcement, and Marine Protected Areas.
Coral reefs are one of the most at-risk ecosystems from global climate change. Sharks and rays are crucial for coral reef ecosystems to function and cover a range of ecological niches; from filter feeders to apex predators. Although overfishing has previously been attributed to steep declines in some populations, there are still questions over the global status of sharks and rays living in coral reefs.
Using the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, Samantha Sherman and colleagues evaluated the extinction risk of all 134 coral reef associated shark and ray species. They also compared their status with all other coral reef species. The authors found that 59% of coral reef shark and ray species are threatened with extinction, such as the whitefin topeshark and the coach whipray, making them the most threatened group in the world, other than marine mammals. They also found that fishing was the main threat to these species, compounded by habitat loss and climate change. Extinction risk was found to be greatest for widely distributed large species, such as the bull shark and reef manta ray, both found in the waters of over 60 countries. Extinction risk was also greatest in nations with greater fishing pressure and weaker governance, such as Brazil, Tanzania, and Indonesia.
The findings suggest that without action to improve the conservation of sharks and rays on coral reefs, declines could have serious consequences for the health of coral reefs and the hundreds of millions of people in coastal communities that rely on them.
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