Number 2 in a farewell list of foods, people, and things about the Seattle food scene I’ll miss most when I move back to San Francisco.I’d never encountered black cod (aka sablefish) before moving to Seattle, when I tasted it at Ray’s Boathouse during an early roundup of classic Seattle restaurants. The cubes of lightly smoked sablefish I tried there sparked one of those holy-shit moments: Unctuous and meaty, impossibly buttery, it tasted like the seafood equivalent of pork belly. For the past three years, it has been nigh impossible to pass over when it shows up on a menu (and it’s going to be the centerpiece of this year’s Christmas dinner).Having moved here from San Francisco, which likes to think of itself as a seafood-savvy town (snicker), I wondered: How could a fish so good be completely unknown 800 miles south? When I first met seafood expert Jon Rowley I asked him that very question. He explained that for many years the Japanese had the lock on the Alaskan market, and up until recently, little Alaskan sablefish made it to Seattle tables, let alone cities farther south. (In a September 2009 Times article, Braiden Rex-Johnson recounts how Seattle chefs adapted and popularized black cod kasuzake, now a Seattle standard.) I love best the fact that there’s no guilt in eating black cod — the Monterey Bay Aquarium Seafood Watch designates it a “best choice.” Though I expect to see much less black cod in the Bay Area, if California cooks are finally catching on to its appeal, the fishery appears to be so well managed that black cod won’t soon go the way of monkfish, skate, Patagonian toothfish, and other species whose surges in trendiness resulted in severe overfishing.