81% of tuna catch comes from stocks at healthy levels, 15% require stronger management

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Of the total commercial tuna catch worldwide, 81% came from stocks at "healthy" levels of abundance, according to the October 2019 International Seafood Sustainability Foundation (ISSF) Status of the Stocks report. In addition, 15% of the total tuna catch was from overfished stocks, and 4% was from stocks at an intermediate level of abundance.

Albacore and skipjack stocks in all four major tuna fishing regions are rated as healthy, but several tuna stocks worldwide are considered overfished:

  • The Atlantic Ocean bigeye and Indian Ocean yellowfin tuna stocks are overfished and overfishing is taking place.
  • Noting the high uncertainty levels in assessments, ISSF is taking a cautious view and considers that the Eastern Pacific Yellowfin and Bigeye tuna stocks are experiencing overfishing and that the Yellowfin stock is overfished.
  • Overfishing is occurring on the Pacific bluefin tuna stock and the stock is heavily overfished.

ISSF publishes its signature Status of the Stocks report twice each year using the most current scientific data on 23 major commercial tuna stocks.

Key Statistics in the Report

  • Abundance or "spawning biomass" levels: Globally, 61% of the 23 stocks are at a healthy level of abundance, 17% are overfished and 22% are at an intermediate level.
  • Fishing mortality levels: 78% of the 23 stocks are experiencing a well-managed fishing mortality rate, and 22% are experiencing overfishing.
  • Total catch: In 2017, as reported in the new report, the total major commercial tuna catch was 4.9 million tonnes, a decrease of 2% from 2016. More than half of the total catch (56%) was skipjack tuna, followed by yellowfin (30%), bigeye (8%) and albacore (5%). Bluefin tunas (three species) accounted for 1% of the global catch. These percentages changed only slightly from the previous Status of the Stocks report.
  • Largest tuna catches by stock: The five largest catches in tonnes, unchanged since the previous report, are Western Pacific Ocean skipjack, Western Pacific Ocean yellowfin, Indian Ocean skipjack, Indian Ocean yellowfin and Eastern Pacific Ocean skipjack.
  • Tuna production by region: More than half (52%) of the world's is harvested from the Western and Central Pacific Ocean, followed by the Indian Ocean (20%), Eastern Pacific Ocean (13%) and Atlantic Ocean (11%). Catch from Pacific-wide stocks accounts for around 3% of the global catch, while catch in the Southern Hemisphere accounts for less than 1%.
  • Tuna production by fishing gear: 65% of the catch is made by purse seining, followed by longline (11%), pole-and-line (8%), gillnets (4%) and miscellaneous gears (12%). These percentages have not changed since the previous report.

The Status of the Stocks report is reviewed by the ISSF Scientific Advisory Committee, which provides advice on its content. The report does not advocate any particular seafood purchase decisions.

Provided by International Seafood Sustainability Foundation

Citation: 81% of tuna catch comes from stocks at healthy levels, 15% require stronger management (2019, October 24) retrieved 8 December 2023 from https://phys.org/news/2019-10-tuna-stocks-healthy-require-stronger.html
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