“I wouldn’t worry about it,” Ukiuchi said, strolling through Tokyo’s main fish market Friday. “We’re not talking about eating 10 tuna sushi every day — in which case I might be a little bit worried.”

Recent reports in the United States about high levels of mercury in tuna served at ubiquitous sushi restaurants in New York have been met with a collective yawn in Japan, the world’s undisputed sushi capital.

Ukiuchi’s relaxed attitude about mercury — which in high concentrations can cause severe brain damage — is matched by the Japanese government, which exempts tuna from its legal limits on mercury in seafood because it’s not caught coastally.

Rules ban many types of seafood if the concentration of mercury exceeds 0.4 parts per million. The limit is 0.3 ppm for mercury’s more dangerous derivative, methylmercury.

The restriction was set in the 1970s after outbreaks of industrial mercury poisoning in the southern town of Minamata that sickened thousands and caused hideous birth defects in the 1950s and ‘60s.

Victims fought for more than a decade before the government and Chisso Corp., which contaminated fishing grounds the victims ate from, acknowledged the poisoning and provided widespread compensation.

Despite the absence of any restrictions on mercury in tuna, officials periodically check the fish, which is one of the most popular dishes in Japan. The country consumes some 450,000 tons of it a year, making it the world’s largest consumer, according to the Organization for the Promotion of Responsible Tuna Fisheries, a Tokyo-based industry group.

The government has issued advisories warning pregnant women and young children to limit their consumption of tuna, but mercury — the Minamata tragedy notwithstanding — does not seem to be a high priority for officials.

“We consider pregnant women a high-risk group, but ordinary people are fine as long as they continue a balanced, healthy diet,” said Yuichiro Ejima, a ministry official in charge of food safety.

The circumspect view was a contrast to Japanese consumers’ scare over mad cow disease. Tokyo shut down its imports of American beef for two years after a single case of the disease was discovered in the U.S. herd.

The New York Times, in a story published Thursday, reported eight of 44 pieces of sushi sampled from local restaurants and stores had mercury concentrations over 1 ppm, a level the paper reported would allow the U.S. Food and Drug Administration to take the fish off the market.

Ejima said the most dangerous thing he took from the report was that it could spread “groundless rumors.”

The denizens of the fish market in Tokyo — the largest in the world — also were skeptical about the worries, expressing confidence that Japanese food safety standards would protect them.

“Where did that tuna in New York come from? I bet it’s not from Japan,” said fish shop owner Yoshiaki Saito. “Fresh tuna from the Japanese coast should be fine — it’s the best.”

Sushi lovers said it would take more than a U.S. report to take them away from their tuna rolls, and they argued a little mercury was probably harmless compared to the fats and oils in something like a hamburger and fries.