Tuna is confusing enough for sustainable seafood consumers. Bluefin and tongol are always no-nos, while skipjack is usually OK, according to the Seafood Watch Pocket Guide.

But albacore, bigeye and yellowfin depend on how they were caught: Longline lands on the red "Avoid" list, while troll- and pole-caught - especially in U.S. and British Colombian waters - earns a yellow or green listing.

Going deeper with its recommendations, the Monterey Bay Aquarium just added most canned tuna products to its Seafood Watch "avoid" list. The only exception is canned tuna labled troll- or pole-caught: White (albacore) makes the "Good Alternatives" list, while light (usually skipjack) ascends to the "Best Choices."

Download your updated Seafood Watch Pocket Guide from the Aquarium's website.

“It’s tricky for consumers who care about healthy oceans to find good information on the label when they’re shopping for canned tuna – either about fishing methods or even the species of tuna in the can,” said Stephanie Bradley, fisheries research manager for Seafood Watch. “That’s changing, as more people ask questions of their retailers…Over time, consumers should expect to see more ocean-friendly options available as producers respond to retailer and consumer interest."