Overfishing drives over one-third of all sharks and rays toward a global extinction crisis

Nicholas K Dulvy,John K Carlson,Katelyn B Herman,Colin A Simpfendorfer,Cassandra L Rigby,Nathan Pacoureau,Sonja V Fordham,Daniel Fernando,Caroline M Pollock,Wade J Vanderwright,Gina M Ralph,Jay H Matsushiba,Rima W Jabado,Julia M Lawson,C Samantha Sherman,Danielle H Derrick,David A Ebert,Brittany Finucci,Jessica Cheok,R Pollom ,K K Bineesh ,Rachel H L Walls ,Craig Hilton‐Taylor ,Patrícia Charvet

doi:10.1016/j.cub.2021.08.062

Abstract

The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes-sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species were threatened. Now, 391 (32.6%) species are threatened with extinction. When this percentage of threat is applied to Data Deficient species, more than one-third (37.5%) of chondrichthyans are estimated to be threatened, with much of this change resulting from new information. Three species are Critically Endangered (Possibly Extinct), representing possibly the first global marine fish extinctions due to overfishing. Consequently, the chondrichthyan extinction rate is potentially 25 extinctions per million species years, comparable to that of terrestrial vertebrates. Overfishing is the universal threat affecting all 391 threatened species and is the sole threat for 67.3% of species and interacts with three other threats for the remaining third: loss and degradation of habitat (31.2% of threatened species), climate change (10.2%), and pollution (6.9%). Species are disproportionately threatened in tropical and subtropical coastal waters. Science-based limits on fishing, effective marine protected areas, and approaches that reduce or eliminate fishing mortality are urgently needed to minimize mortality of threatened species and ensure sustainable catch and trade of others. Immediate action is essential to prevent further extinctions and protect the potential for food security and ecosystem functions provided by this iconic lineage of predators.

Highlights

Human activity has affected the ocean for centuries, directly through fishing and hunting, and indirectly by habitat modification and climate change.[1,2,3] These effects, coupled with those on land, have heralded a new geological epoch— the Anthropocene—characterized by rapid environmental transitions driven by humanity.[4]
Overall number and percent threatened We estimate over one-third of chondrichthyans are threatened with extinction globally, based on the observed number of threatened species combined with the estimated number of Data Deficient (DD) species that are likely to be threatened (Figure 1A)
If we assume that DD species are threatened in proportion to the other species, over one-third (37.5%) of chondrichthyans are threatened, with a lower estimate of 32.6% and an upper estimate of 45.5%

Summary

Introduction

Human activity has affected the ocean for centuries, directly through fishing and hunting, and indirectly by habitat modification and climate change.[1,2,3] These effects, coupled with those on land, have heralded a new geological epoch— the Anthropocene—characterized by rapid environmental transitions driven by humanity.[4] On land, the Anthropocene has seen. Current Biology 31, 1–15, November 8, 2021 a 2021 The Author(s). Statistical predictions, based on life histories, catch, and fisheries development, warn that the unassessed data-poor fisheries, for sharks, may be highly unsustainable.[12]

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