Conservation groups could only look on and shake their heads as Kiyoshi Kimura celebrated his record purchase of a 612-pound mammoth of a bluefin tuna in front of cameras and crowds.

“The celebration surrounding the annual Pacific bluefin auction hides how deeply in trouble this species really is,” Jamie Gibbon of tuna conservation group The Pew Charitable Trusts told the Associated Press.

The quarter-ton tuna was purchased by Kimura — the "Tuna King" who owns the Sushi Zanmai chain — for a record-setting 333.6 million yen, or nearly $3 million. The buy doubled the previous record of $1.76 million set in 2013, also by Kimura.

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But tuna are being overfished as consumption rates rise. The Pacific bluefin tuna population has plummeted 96 percent from pre-industrial numbers, triggering fears from experts that the fish could face extinction.

Japan, which accounts for 80 percent of the global bluefin consumption, along with Mexico, Korea and the United States have exceeded their fishing quotas in a number of the last few years, NPR reported.

The Pacific bluefin, Atlantic bluefin and Southern bluefin are listed as vulnerable, endangered and critically endangered, respectively, by the International Union for Conservation and Nature.

A pair of groups working to restore the population of the Pacific bluefin hope to bring the species back to 20 percent of their pre-industrial numbers by 2034. The Western and Central Pacific Fisheries Commission and the Inter-American Tropical Tuna Commission would increase the population seven times over if they successfully managed the population.