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Articles on International Union for Conservation of Nature

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Dodos have been extinct for centuries, but it’s not a simple matter to definitively designate a species as extinct. (Shutterstock)

When is a species really extinct?

Species are declared extinct when there have been no verifiable sightings for 50 years. Declaring a species extinct has implications for conservation efforts and policies.
Sharks and rays have ruled the ocean for 420 million years, but that reign may be slipping. (Mark Erdmann)

Sharks and rays are in free fall: More than one-third are threatened with extinction from overfishing

Nearly all species of sharks and rays are captured in fishing operations. But research shows that fishing quotas and closing some areas to fishing can help rebuild threatened populations.

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