AP PHOTOS: First tuna of the year sells for 4.5 million yen at Japan's Tsukiji market

A single bluefin tuna has sold for 4.5 million yen ($37,500) in annual celebratory bidding at the first auction of the year at Tokyo's famous fish market.

Kiyoshi Kimura, the owner of a Japanese sushi restaurant chain, bought the 180-kilogram (400-pound) fish Monday at the re-opening of the Tsukiji market after the extended New Year's break.

He was the top bidder for the fourth year in a row.

Hundreds of tuna are sold daily at the early morning auction.

The popularity of tuna for sushi and sashimi has depleted stocks globally. In November, the International Union for Conservation of Nature designated Pacific bluefin as a species threatened by extinction.