A Japanese restaurant operator has started using dried bonito flakes certified as caught and processed in an eco-friendly way as part of efforts to maintain both the country's culinary culture and fishery resources.

Kijima Co. based in Yokohama near Tokyo on June 8 began serving at all of its six restaurants dishes using special bonito flakes, which are a key ingredient in "washoku" traditional Japanese cuisine.

The product is made by Yamaki Co., which obtained the certification from the Marine Stewardship Council, a London-based nonprofit organization, in 2019 for its practice of avoiding overfishing and good management of its supply chain.

Supplied file photo shows bonito fishing using a pole and line method. (Photo courtesy of Yamaki Co.)(Kyodo)

"This is an important step forward to show that caring about sustainability is compatible with running businesses," said Hiroaki Kijima, director of the business strategy office at the restaurant operator, in an online press conference.

Washoku, or traditional Japanese cuisine, was added to the list of U.N. Educational, Scientific and Cultural Organization's Intangible Cultural Heritage in 2013.

With the global consumption of marine products continuing to increase, about 30 percent of the resources were overfished as of 2017, according to the Food and Agriculture Organization of the United Nations.

Annual bonito catches have also increased to around 3 million tons in recent years, raising concerns over future stocks left in the ocean. Japan accounts for about 10 percent of global bonito consumption, mostly as dried flakes, according to an estimation by the World Wide Fund for Nature.

Photo shows bonito flakes. (Los Angeles Times/Getty/Kyodo)

Yamaki's MSC certified bonitos are caught by an eco-friendly pole and line method used to catch large midwater species one fish at a time, rather than usual net fishing, said Hironori Tanaka, general manager of the corporate communication department at the company.

The bonitos are traceable and separated from non-certified products in the supply chain, he added.

By processing the bonitos while keeping their freshness, the "dashi" soup stock extracted from the flakes has a rich aroma and umami savory flavor, Tanaka said.

But the output of Yamaki's certified bonito flakes is still limited and only a few restaurants meet the MSC requirements of properly managing products from certified sustainable fisheries, he said.

"I hope our efforts will motivate other restaurants, retailers and fishery operators to work for preserving the resources for the future," Kijima said.