Unless you’ve been sharing a shell with a hermit crab, you’ve probably come across the Monterey Bay Aquarium’s Seafood Watch Sustainable Seafood Guide. Last week the Aquarium, together with the Blue Ocean Institute and the Environmental Defense Fund, launched a guide specifically for sushi with a “national sushi party” and an invite-only shindig at San Francisco’s Tataki Sushi and Sake Bar.

The color-coded columns on the wallet-sized guide divide popular sushi preparations based on whether or not they are caught or farmed in ways that compromise the health of the ocean and pose a health risk to consumers.

Alas, the red “avoid” list reads like the obituaries of friends dear to my heart: farmed salmon (sake), freshwater eel (unagi) and imported farmed yellowtail (hamachi). I can already hear bluefin tuna (hon maguro/kuro maguro) lovers weeping.

Then I discovered Tataki in San Fran’s Pacific Heights neighborhood (2815 California St., San Francisco, 415-931-1182). The forward-thinking restaurant touts itself as the world’s pioneer in serving only sustainable sushi.

The nature-inspired décor of the restaurant– hand-hewn bamboo tables and ochre-colored walls– was a perfect complement to the eco-friendly menu. We started off with several nigiri. We ordered two specials: wild Alaskan salmon (sake) sprinkled with sea salt and local line-caught skipjack tuna (katsuo). A cheaper net-caught katsuo from New Zealand was also available, but we opted for the fresher fish from the California coast. The milky-white Hokkaido scallops (hotate) that followed melted like a pat of butter in my mouth.

Next in line was the 49er Roll. Smelt roe (masago) and avocado were rolled into vinegary rice and topped with the peach-colored flesh of arctic char (iwana)– a tasty, ocean-friendly substitute for farmed salmon– and fresh lemon slices. The kicker was the Extinguisher Roll, spicy Hawaiian amberjack tuna (hamachi) topped with chunks of avocado, a blob of spicy mayonnaise and flaming red habañero masago. Served with a flaming mound of salt soaked in Bacardi 101, it was so good we ordered a second round.

Our meal was outstanding. The seafood was fresh, the preparations innovative and the prices reasonable. I didn’t miss farmed salmon or freshwater eel one bit.

Monterey Bay-area sushi restaurants could do well to follow suit but local consumers can still make informed choices.

Sheila Bowman, Seafood Watch outreach manager, acknowledges that while not everyone can travel to San Francisco to eat at Tataki, you can find your way at your local sushi joint. “Local sushi restaurants have a lot to offer from the green list,” she says, “but we want them to get off the red list.”

Over the phone, Tamotsu Suzuki, manager of Monterey’s popular Crystal Fish (514 Lighthouse Ave., Monterey, 649-3474), rattled off sustainable items like spot prawns (amaebi), sablefish (gindara), bay scallops (hotate) and oysters (kaki) from their menu. They also serve arctic char, Monterey sardines (iwashi) and U.S.-farmed abalone (awabi) on occasion. That day, wild Alaskan salmon was available but Suzuki admitted that they usually carry Scottish farmed salmon, a red-listed item.

I dined at Crystal Fish that very evening. While I had several green-list items to choose from, tuna-belly (toro) and bluefin tuna were staring at me from the Specials board. Our server shifted uncomfortably when I asked where the yellowtail (hamachi) came from and whether wild salmon was available. He obviously didn’t know.

In the end it’s all about supply and demand. If demand for red-list items stays high, they will remain on menus. If we don’t ask questions, servers will not learn how to answer them.

Your sushi choice can have an impact on the future of our oceans. Vote with your chopsticks.

THE SUSHI GUIDES are available at www.blueocean.org; www.edf.org/seafood; and www.seafoodwatch.org/sushi