Hajime Sato -- a self-described "sushi whore" -- has seen the light.

Mashiko, his West Seattle restaurant, celebrates 15 years in business in September. He'll turn 40 in October. Now, he said, is the perfect time to come clean.

"I've been teaching sushi-making for seven or eight years. I teach about eating sustainable fish, but in my restaurant I use fish I know I should not be using. I feel like a hypocrite. I want to sleep good at night!" Soon enough, he'll be sleeping peacefully.

On August 15, Mashiko will be reborn as Seattle's first fully sustainable sushi restaurant. Which is to say that Sato will just say no to endangered fish and other seafood caught or raised using non-sustainable practices. He's 86-ing sushi bar-staples like Atlantic salmon, black tiger shrimp from Southeast Asia, farm-raised unagi (freshwater eel) and hamachi (Japanese amberjack) -- while proudly waving the oshibori of conservationism.

Hajime Sato: the first cut is the hardest (photo/Jessica Oyanagi)

Sato has been spurred on and mentored by seafood activist Casson Trenor, author of "Sustainable Sushi: A Guide to Saving the Oceans One Bite at a Time" and guiding light at Tataki Sushi & Sake Bar in San Francisco. (Do check out his stunning Web site, sustainablesushi.net.)

Casson Trenor -- sings the song of seafood sustainability (photo Kristen Policy)

The pair met in April at a Seattle dinner meant to prove to local industry professionals that it's easier to practice what the "sustainability guru" preaches than one might think.

Sato "showed up on his motorcycle in his leather jacket and he's kind of got that attitude, kind of bad-ass," Trenor recalls of the event, held during his recent book tour. "And he's kind of like, `What the hell is this? Why am I here?'"

An invited guest, Sato didn't say much at first, but as he ate course after course of sushi prepared by visiting-chef Kin Lui of Tataki, he grew visibly inspired. "He became quite vociferous in his agreement of some of the things I was saying," said Trenor. "Like how we needed to move to [eating] smaller fish and go back to the hikarimono, the silvery-skinned finfish like the mackerels and sardines, and away from things like bluefin tuna."

At meal's end, Trenor addressed the crowd. "So, you just ate a sustainable sushi meal," he said. "How do you feel?" They answered with applause, though the West Seattle sushi-chef made an even bolder statement: "Hajime stood up, banged his fist on the counter and said, `god damn it, all right! I'm going to do it!' And that's it. He's never looked back."

"On that day," Sato recalls, "I said within three months I'm going to go sustainable. Period." Since then, he's worked hard to do just that. He's made a pilgrimage to San Francisco, where he visited Takaki. And had some frank discussions with officials from the Monterrey Bay Aquarium's Seafood Watch, whose color-coded Sustainable Seafood pocket guides are the answer to the "What to eat? What to avoid?" conundrum.

"Sheila [Bowman] was almost rude to me," he said of the Seafood Watch's senior outreach manager, who was skeptical at first about his efforts to become fully sustainable at Mashiko. "She told me so many sushi chefs say they're going to do it, but for them it's a marketing scheme. They say they're `sustainable' and then ask, `Can I use a little bit of bluefin?' and she says, `No! You can't!'"

Get Sato talking about bluefin and he rises swiftly to the bait.

"I love local sardines," he said of the seasonal delicacy. "I personally look forward to eating them every year. But do you know how long the season was this year? Two weeks. It's done. It's over." Blame it on bluefin ranching, he explains, saving a healthy dose of ire for the tuna cowboys who profit selling the sought-after seafood. "There's a quota for sardines in the U.S." -- one that doesn't extend into Canada. "It takes 25 kilos of sardines to make one kilo of bluefin," he notes, citing a single fishing vessel said to have reeled in a million tons of Northwest sardines destined for tuna pens worldwide. "I'm appalled by that. I'm sad."

Yes, he's served endangered bluefin at Mashiko, but no longer. These days he's a convert, viewing bluefin through the eyes of a environmentalist in love with the foods that earn him his keep. "Would you go to Africa and shoot a lion and eat it?" hes asks. "No. Then why are you eating the bluefin tuna that's close to extinction? What's the difference?"

Making a difference is what it's is all about, Sato said. He hopes to make that difference one customer at a time. "For me, this is not just a niche and a gimmick. It's a way of saying, `Let's do this together, so the whole fishing industry can survive.'"

Lately, he's been busy hounding his vendors, in search of products we may not be familiar with, like hebi, an Hawaiian spearfish viewed by many as "trash fish," but eminently edible as sushi, says he. And he's turning to the far-too-few sustainably minded seafood farmers, he said, to provide him with catfish (from North Carolina), rainbow trout (from Idaho) and coho salmon (here in Washington).

In Seattle, as elsewhere, selling carefully sourced seafood is hardly news: it's become a way of life for many local chefs and restaurateurs. But trying to get sushi chefs on board hasn't been easy, Trenor said. Sato has been an exception. His willingness to get creative with his sourcing and turn Seattle on to a new way of looking at sushi by delving deeper down the food-chain puts him at the forefront of what they both hope will be a sushi revolution.

"Mashiko is allowing us, basically, the opportunity to use sushi as a vehicle, or as a lens through which we can better express the terroir of Puget Sound," said Trenor, a Mukilteo native. As illustration, Sato plans to lard his lengthy menu with such lesser-known products as moonsnails and limpets, and has thrown the idea out to Bill Taylor of Shelton-based Taylor Shellfish Farms. "I said, `Bring it on! Let's see what happens.' And Bill said, `OK, let's do it. Let's have some fun!'"

Sato has even convinced his B.C. black cod-purveyor to save and sell him black cod liver, a replacement for the monkfish liver prized by so many of his customers (monkfish has earned a solid position on the Seafood Watch "avoid" list). The black cod liver's fresh clean flavor has been a hit, Sato said. "We've been selling something like five pounds a week."

"It's the first time a traditionally trained Japanese sushi chef has incorporated environmental sustainability into a restaurant to the degree of making it the guiding principal of the business," Trenor said. "I'm just so excited about this. It's a huge, huge event for the movement."

Japanese sushi-chefs can be "really stubborn," agrees Sato, who grew up in a Tokyo suburb. "Any chef who's using the same product for a long time, it's hard for them to change. They serve what they believe is `traditional.'"

Tradition has never been his forte, as anyone who's seen his sushi-bar sidekick Mariah Kmitta, will tell you. "That's another thing that pisses me off," said Sato of Kmitta's presence behind his sushi bar, where she's been for nine years. "That thing about a woman's hand being `warmer.' That's such nonsense. If you read any history of sushi, you'll learn that about 200 years ago the sushi chefs were all female. The guys were the vendors and the girls were the ones making sushi."

Between his springtime revelation and the upcoming menu makeover, there's been a movement toward sustainability, though Mashiko patrons haven't had to go cold turkey -- yet. "We still have hamachi, unagi, maybe another week's stock," Sato notes. But he won't be buying any more. Nor will he be raising prices.

"If I raise the price there's no point in doing this," he said. By keeping prices competitive and succeeding he may hopes to follow in his Trenor's footsteps -- convincing other sushi chefs that going green can also bring in the green.

"My restaurant's doing great. On any given day of the week there's an hour wait to get in," Sato insists. But he readily admits that unlike sushi newcomers Tataki or Portland's sustainable Bamboo Sushi restaurant (home to head-chef Brandon Hill, late of Seattle's Wasabi Bistro and Bonzai Sushi), he is an established operator with a hardcore customer base. Which makes him far more willing to embrace this sea change.

Hajime, preparing to feed his fans (photo J. Nichole Smith)

Looking back over the history of sushi-making and the rise of the sushi bar in Japan and elsewhere, he said, "We used to throw away tuna not so long ago. Big-eye and bluefin were considered trash. During the Edo era you ate snapper, flounder, half-beak, sardines -- whatever was in front of you, whatever's fresh and good." Looking at the rise of the sushi economy today, its impact on the decline of seafood stocks worldwide has exacted too steep a price, he said.

But with Trenor helping show him the way, Sato is convinced he can help turn that tide. "Let's change it. Let's risk it. We might lose some business from people who like to eat toro or unagi all the time," he said. "But we have to do this. We must do this. Because five, ten years from now, we're not going to have any fish left."