Japanese sushi maestro Jiro Ono, whose creations were recently enjoyed by US President Barack Obama and are reputedly the best in the world, warned Tuesday of a sea of change in ingredients due to overfishing.
"I can't imagine at all that sushi in the future will be made of the same materials we use today," the 89-year-old master told the Foreign Correspondents Club of Japan.
Ono owns the three Michelin-starred Sukiyabashi Jiro restaurant - dubbed the world's best sushi establishment - and was the subject of the 2011 documentary Jiro Dreams of Sushi.
"I told my young men three years ago sushi materials will totally change in five years," he added. "And now, such a trend is becoming a reality little by little."
Ono referred in particular to a short supply of high-quality domestic tuna, which has prompted sushi dealers in Japan to source Atlantic bluefin varieties instead.
His eldest son Yoshikazu, 53, who helps Ono run the restaurant, explained growing demand for tuna amid a global sushi boom is leading the domestic industry to depend more and more on farmed fish.
The younger Ono also warned of a shrinking stock of highly prized shellfish such as abalone and ark shell, which need more than five years to mature.
"They catch them all together (before some are ready), pushing the stock to deplete."
Their basement restaurant, which seats just 10 at a counter, opened its doors in 1965 and has remained in an ageing commercial building in a corner of the Ginza district ever since.
It has gained fame for Ono's rigid discipline and pursuit of perfection, earning three Michelin stars every year since 2007 when the Tokyo edition of the gourmet guide was launched.
When US President Barack Obama travelled to Tokyo last April, he joined a long list of Ono's celebrity guests, including French master chef Joel Robuchon and Hollywood stars Hugh Jackman and Katy Perry.
As Obama and Abe went straight into "business-like talks," focusing on trade, the senior Ono kept serving his own selection of 20 pieces as he does to everyone else, his son said.
"He (Obama) seemed to like chu-toro (medium fatty tuna) very much because he winked when he ate it."
"The president ate them all," the younger Ono said, apparently in reference to reports the president had stopped halfway through the meal, praising the way he skilfully tackled the delicacies.
"He said three times, 'This is the best sushi I've ever had in my life'," he added.
About 70 percent of Ono's customers, who pay an eyebrow-raising base price of 30 000 yen (R2929) for a set of 20 pieces of sushi, are now said to be foreigners.