Wild-caught Alaskan salmon, bay scallops, Chilean seabass—as a responsible seafood eater, do you know which ones to avoid and which get a thumbs up? Chances are, you’re as confused as most consumers when it comes to seafood. And who wouldn’t be? With boycotts coming and going every few years, it’s difficult to stay on top of a politically correct seafood diet.

That’s where the Monterey Bay Aquarium in California comes in. The aquarium’s Seafood Watch, a wallet-size guide, categorizes seafood into “Best Choices” (wild-caught Alaskan salmon), “Proceed with Caution” (bay scallops), and “Avoid” (Chilean seabass). The categories are based on the size of the species stocks and how the means of obtaining them affects the health of the oceans. The list is reviewed by marine biologists in consultation with fisheries managers and updated periodically to reflect the status of global fisheries.

To date the aquarium has distributed about 85,000 cards, including 10,000 downloaded from its website. The aquarium’s food service vendor, Bon Appetit, has requested 5,000 cards to distribute through its 150 corporate clients (including The Getty Center in Los Angeles, Stanford University, Hewlett-Packard, and Georgetown University Law School).

Why the sustained interest? “Over-fished stocks and unsustainable aquaculture products continue to be sold in markets and restaurants. And new items come online frequently about which little is known,” says aquarium spokesperson Ken Peterson. “Buying seafood is not like buying beef, chicken, pork, or tofu. Most fish are still ‘hunted’ from the wild, and some species can withstand this pressure much better than others.”

The Monterey Bay Aquarium’s Portola Café and Restaurant serves only seafood on the Best Choices and Proceed with Caution lists. “Since we launched Seafood Watch, we no longer serve swordfish, rockfish from the Sebastes family, farmed salmon, or farmed shrimp. We’ve also switched from beluga caviar to caviar from farmed sturgeon,” Peterson says.