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Nature

Populations Of Pacific Bluefin Tuna Have Crashed By 97 Percent

author

Josh Davis

Staff Writer

clockApr 27 2016, 11:33 UTC
7 Populations Of Pacific Bluefin Tuna Have Crashed By 97 Percent
Ugo Montaldo/Shutterstock

The wild stocks of Pacific bluefin tuna, favored in Japan among sushi lovers, are on the brink of ruin. A draft summary of a new report looking into the survival of the species warns that the fish have now been depleted to just 2.6 percent of their original numbers, and are faring much worse than the last report on the species that was issued two years ago. Unless something is done now, the fish will soon be gone forever.

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Issued by the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean, the report will be fully reviewed by the committee in July. The report details that the tuna (Thunnus orientalis) is being harvested in some areas at up to three times the sustainable rate, and yet despite this, limits set after previous estimates were made still allowed some countries who fish the tuna to up their catch. At the current level of fishing, the report states that there is just a 0.1 percent chance that the species will recover to healthy numbers.

“The situation is really as bad as it appears,” Amanda Nickson, the director of Global Tuna Conservation at the Pew Charitable Trust, told the Associated Press. The current finding, produced by independent scientists, is much worse than estimates from the report released in 2014. Back then, they thought that the Pacific bluefin was sitting at around 4.2 percent of their pre-fishing stock, which was already considered dire. Now it seems the situation has become worse, with a population decline of more than 97 percent over less than a decade.

Over 80 percent of all Pacific bluefin tuna is consumed by the Japanese, who favor the fish for sushi. Large tuna specimens can sell for upward of $1 million. Sean Pavone/Shutterstock

Even up until 2014, it was thought that their recruitment numbers, or the number of fish that survive to adulthood, averaged at around 15 million individuals. In 2011, the International Union for the Conservation of Nature only considered the fish to be of “least concern.” Within just a couple of years, however, their numbers declined so sharply that this had to be reconsidered, although even today they are still listed as “vulnerable.”  

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Nowadays, it is thought that fewer than 3.7 million of the fish survive to adulthood each year, the second lowest level ever recorded. Even if fisheries agreed to cut the level of tuna caught by a fifth, the chance that the species will recover to healthy levels is still only estimated to be at 3 percent. One of the main issues stopping the sustainable management of the tuna is the fact that they migrate such vast distances within the Pacific, meaning that they cross into a multitude of different fisheries. This has led to the call for a single organization to take control of their management.

So far, organizations that help manage bluefin fisheries have established a goal of increasing Pacific bluefin numbers to 6.4 percent of original stock by 2024, but even this is thought to be way lower than the level needed for a sustainable fishery, estimated to be around 20 percent of pre-fishing levels. In order for this to happen, the number of tuna caught has to be dramatically cut – and soon. 


Nature
  • iucn,

  • extinction,

  • tuna,

  • Japan,

  • fishing,

  • over fishing,

  • bluefin tuna