Seventy years of tunas, billfishes, and sharks as sentinels of global ocean health

Fishing activity is closely monitored to an increasing degree, but its effects on biodiversity have not received such attention. Using iconic and well-studied fish species such as tunas, billfishes, and sharks, we calculate a continuous Red List Index of yearly changes in extinction risk over 70 years to track progress toward global sustainability and biodiversity targets. We show that this well-established biodiversity indicator is highly sensitive and responsive to fishing mortality. After similar to 58 years of increasing risk of extinction, effective fisheries management has shifted the biodiversity loss curve for tunas and billfishes, whereas the curve continues to worsen for sharks, which are highly undermanaged. While populations of highly valuable commercial species are being rebuilt, the next management challenge is to halt and reverse the harm afflicted by these same fisheries to broad oceanic biodiversity.

Automated summary

This study uses iconic and well-studied fish species to calculate yearly changes in extinction risk and track progress towards global sustainability and biodiversity targets. The study finds that the biodiversity loss curve has shifted for certain fish species with effective fisheries management, but continues to worsen for sharks which are undermanaged.