Overfishing is driving reef sharks toward extinction, according to new study published in Science.

The five main shark species that live on coral reefs—grey reef, blacktip reef, whitetip reef, nurse and Caribbean reef sharks—have declined globally by an average of 63 percent, according to the scientists of Global FinPrint, a five-year international study supported by the Paul G. Allen Family Foundation.

Results from this latest research, which includes 22,000 hr. of video footage from baited underwater video stations across 391 reefs in 67 nations and territories, indicates widespread overfishing is the main culprit driving reef sharks toward extinction.

Sharks and rays are common in coral reef ecosystems, but as reefs are more heavily fished, they have become stripped of both shark and ray species or stripped of just shark species, leaving the ecosystem dominated by rays. The loss of sharks could have an impact on the overall health and function of the coral reef ecosystem.

Early results from this study were previously used to update the status of four of these species to more threatened categories on the International Union for the Conservation of Nature’s (IUCN) Red List. They were also presented during the most recent Conference of the Parties of the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES), helping world governments to make the groundbreaking decision to better regulate trade in these and more than 50 additional species of sharks.

More than 150 researchers from more than 120 institutions around the world contributed to the research.

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