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Study

Half a century of global decline in oceanic sharks and rays

Pacoureau, Nathan; Rigby, Cassandra L.; Kyne, Peter M.; Sherley, Richard B.; Winker, Henning; Carlson, John K.; Dulvy, Nicholas K.

Nature, 2021

Peer-reviewedmeta analysiswild

What they did

Abundance time series for oceanic sharks and rays were assembled and modelled to estimate a global relative abundance index since 1970, alongside a fishing-pressure index and Red List reassessment.

Studied in
Chondrichthyes
Sample size
31 oceanic shark and ray species with global abundance time series

What they found

Global oceanic shark and ray abundance declined by around 71% since 1970, driven by an eighteen-fold increase in relative fishing pressure, leaving three quarters of the species assessed threatened with extinction.

What it means

The authors' reading, and ours. Where they differ, that difference is the point.

How the authors put it

Oceanic sharks and rays have undergone a severe global decline requiring immediate catch limits.

How NatureHQ reads it

Abundance indices assembled from fisheries data carry real uncertainty, and the headline percentage should be read as an estimate with a wide interval rather than a measurement. What is not in doubt is the direction and the mechanism. It also sets the honest proportions for the topic: the number of people killed by sharks each year is around ten, and the number of sharks killed by people is estimated in the tens of millions.

Limitations

  • Fishery-dependent data can reflect changes in fishing behaviour as well as in abundance.
  • Coverage is uneven, with the Atlantic and Pacific far better sampled than the Indian Ocean.
  • Oceanic species only; coastal and deepwater trends differ.

What this study is used for on NatureHQ

One study can inform several subjects. Here is everywhere this one is cited.

Finding the paper

Published by: Nature PortfolioPublished in a Nature Portfolio journal.

doi.org/10.1038/s41586-020-03173-9

This reference was resolved automatically against Crossref on 2026-08-11.

NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.