Raw tuna is giving Tateki Suzuki a headache.
He is torn between charging more for a serving of tuna sushi and risking a customer exodus from the 28 stand-up restaurants he manages in Tokyo.
"Our whole sales concept is ¥75 (US$0.65) a piece," says Suzuki, 53. "We have to protect that."
Wholesale prices for Japan's favorite fish have surged as much as 84 percent in the past year because of rising fuel costs and shrinking catch quotas. With the nation just emerging from seven years of deflation, retailers haven't been able to pass on the increase to consumers.
"We can't raise retail prices so much because competition is tough and we'll lose customers," says Kaori Watanabe, a spokeswoman for Chiba-based Aeon Corp, Japan's biggest retailer by sales, which operates 380 supermarkets.
Aeon has kept the price of frozen tuna within a band of is ¥1,980 to is ¥2,480 a kilogram this year, Watanabe says. At Tokyo's Tsukiji fish market, the world's biggest, wholesalers charge is ¥1,250 to is ¥1,580 a kilogram, says Masaki Okahata, a spokesman for Sojitz Corp, Japan's second-largest tuna trading company.
Japanese eat about 571,500 tonnes of tuna a year, which is a third of the world's yearly consumption, according to the Japan Tuna Federation.
Depending on the species, wholesale prices for frozen tuna have jumped 22 percent to 61 percent in a year, according to the Japan Fisheries Information Service Center in Tokyo.
"Stores can't just pass on a 40 percent cost increase to consumers," says Yoshikazu Nahata, a spokesman for Zen-Nippon Shokuhin Co, which operates 1,700 supermarket franchises that specialize in fresh food.
Fresh tuna is even more prohibitive. High-end restaurants and sushi bars are paying is ¥5,188 a kilogram -- 84 percent more than last year, government figures show.