On a 2004 trip to Japan, chef James Corwell visited Tsukiji fish market, the largest fish market in the world. While strolling the market in the early morning, he came across two football field-sized warehouses full of tuna. By mid-morning, the rooms were empty, the tuna sold and on its way to sushi restaurants all over the country.

“I thought, how are the oceans supposed to keep up?” said Corwell as he prepared a maki roll of sushi at the Whole Foods office in Glendale, Calif. “And this happens every day, all over the world.”

The chef, who has worked at Wine Spectator Greystone Restaurant in Napa Valley, Calif., and Le Foret in New Orleans, decided to do something about fish sustainability. He started to develop a tuna substitute called Ahimi (“ahi” is tuna, and “mi” means spirit in Japanese). Whole Foods started selling his faux tuna, in the form of vegan sushi, at select Los Angeles markets on Nov. 1.

Ahimi looks like tuna, with its deep reddish pink color and a glossy, slightly wrinkled exterior, but it’s completely plant-based.

“If you look at the elements of sushi, they are all high in umami,” said Corwell, who spent four years working on the recipe and cooking method for Ahimi. “So I thought, what else is high in umami?”

Corwell decided on tomatoes. The fruit is peeled, seeded and marinated in a mixture of water, sugar, soy sauce and sesame oil. The tomatoes are cooked “low and slow” using a method Corwell is keeping proprietary.

The result is a slice of tomato that looks and tastes like a piece of raw fish. The flavor is clean, with a subtle boost of salt from the soy, as if the “fish” has already been brushed with soy sauce. And the texture is almost identical to raw fish — soft but with a discernible chew. Are you going to mistake Ahimi for actual tuna? Probably not. But it’s similar enough.

“It’s flavored, but chefs who might want to add more to it can,” Corwell said. “I think the timing is finally right for a product like this. You have the awareness around the oceans and fish sustainability like never before.”

Whole Foods will serve the vegan sushi out of its sushi counters in the form of nigiri (Ahimi sliced over sushi rice) and California rolls (avocado rolls with a slice of Ahimi on top). It’s priced at $8.99 for a roll and $11.99 for a roll and nigiri combo.

While vegan sushi already exists in the form of cucumber and avocado rolls, this is the first designed to be an actual tuna substitute. Will it somehow affect this city’s poke trend? We’ll have to wait and see.