The data is clear, and it doesn’t look good. Our oceans are depleted, catches are dropping, fish prices are rising and the situation is only getting worse. What can chefs do about it? If you’re Shinsuke Ishii, you open a specialist seafood restaurant.

It sounds counterintuitive, but Ishii has very good reason to act. He is not only the owner-chef of a Michelin-starred French restaurant — the very excellent and ever-popular Sincere in Sendagaya — he’s also a founder member of the industry pressure group, Chefs For The Blue, which works to promote sustainable seafood. His new project, Sincere Blue, is a labor of love that weaves those two parallel strands together.

It’s housed inside the newly opened Jingumae Comichi, a two-story yokochō-style cluster of bars and diners a short stroll from Harajuku Station. Sincere Blue is Ishii’s hands-on way of demonstrating that a stylish, midrange French restaurant can offer a superb selection of dishes using only fish and other seafood that are not just certified as sustainable, but delicious and affordable. Often this means using less common or well-regarded species that nonetheless make great eating.