TOKYO ` A monster tuna caught off Japan turned heads at a Tokyo fish market Friday, where the 445 kilogram (981 pound) bluefin `` the biggest caught here since 1986 `` sold for 3.2 million yen (36,700 dollars).

"Many of the people who work at the market have never seen a tuna that big," said an official of the Tokyo Metropolitan Government, which runs the Tsukiji fish market, the world`s biggest seafood market.

The fish, which was auctioned at 7,200 yen per kilogram, had already been gutted and cleaned of its gills, meaning it must have weighed more when it was caught off Nagasaki prefecture this week, the official said.

"It is extremely rare to see a tuna heavier than 400 kilograms," he said.

The biggest Japanese tuna sold at Tsukiji was a 496`kilogram beast caught in April 1986 `` but the biggest tuna from the world`s oceans to be sold here was a Canadian fish caught in 1995 weighing 497 kilograms.

Decades of overfishing have seen global tuna stocks crash, pushing some Western nations to call for a trade ban on endangered Atlantic bluefin tuna.

Japan consumes three`quarters of the global bluefin catch, a highly prized sushi ingredient, known in Japan as "kuro maguro" (black tuna) and dubbed by sushi connoisseurs as the "black diamond" because of its scarcity.

A piece of "otoro" or fatty underbelly can cost 2,000 yen (22 dollars) at high`end Tokyo restaurants.

BDST: 13:02 HRS, 16 July 2010