Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats3. Here we address this knowledge gap using data from more than 15,000 standardized baited remote underwater video stations that were deployed on 371 reefs in 58 nations to estimate the conservation status of reef sharks globally. Our results reveal the profound impact that fishing has had on reef shark populations: we observed no sharks on almost 20% of the surveyed reefs. Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population. However, opportunities for the conservation of reef sharks remain: shark sanctuaries, closed areas, catch limits and an absence of gillnets and longlines were associated with a substantially higher relative abundance of reef sharks. These results reveal several policy pathways for the restoration and management of reef shark populations, from direct top-down management of fishing to indirect improvement of governance conditions. Reef shark populations will only have a high chance of recovery by engaging key socio-economic aspects of tropical fisheries.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Core funding for Global FinPrint was provided by the Paul G. Allen Family Foundation (to D. Chapman and M. Heithaus). M.A.M. was supported by the NSERC Canada Research Chairs Program. We thank our individual funders, whose contributions greatly enhanced the sampling coverage of the projects; all of the government permitting agencies that allowed us to work in their waters; the Global FinPrint volunteers from Stony Brook University, Florida International University, James Cook University, the Aquarium of the Pacific and Shedd Aquarium who watched the BRUVS footage; N. A. J. Graham, N. J. Barrowman and J. Zamborian-Mason for helpful comments on drafts of our manuscript and R. Steele for assistance with manuscript preparation.This is contribution #205 from the Coastlines and Oceans Division of the Institute of Environment at Florida International University.