The World Wide Fund for Nature has warned that tuna stocks are disappearing at an alarming rate. The depletion is thought to be due to a combination of poor management of existing stocks and high levels of illegal, unreported fishing.
According to WWF, Atlantic bluefin tuna used for high value sushi and sashimi are "massively overfished" and spawning stocks of Southern bluefin tuna in the Indian Ocean are down by about 90%.
The problems facing tuna fisheries are outlined in a WWF report entitled Tuna in Trouble: Major Problems for the World’s Tuna Fisheries.
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