http://bitten.blogs.nytimes.com/2008/02/12/shopping-for-fish/index.html?hp

Mark Bittman has great advice for the ethical fish buyer..."you’re standing at a fish counter, staring at a piece of fish. You can text Blue Ocean’s Fishphone at 30644 with the message FISH and the name of the fish in question. Immediately you’ll get a text back with an assessment and, when appropriate, a more environmentally sound alternative.

If you put in sea bass, for example, you would get a message back saying, “Black sea bass; U.S. Mid Atlantic (GREEN) few environmental concerns, strong management has helped populations recover from overfishing.”

Green means green light, of course.

And the system is pretty smart. Try “halibut” and you get

Pacific Halibut
(GREEN) few environmental concerns
MSC certified as sustainable;
Atlantic halibut
(RED) significant environmental concerns

“MSC” means that the species has been certified as a “best environmental choice” by the Marine Stewardship Council (www.msc.org).