Greenpeace rates the fish sellers so you don't have to

Are you confused by the many reports about fish, which are safe to eat, which are being depleted? Do you want to do right by the environment but don't know enough about ichthyology (the study of fish)? Greenpeace has just unveiled the latest iteration of its Supermarket Seafood Sustainability rating, and suggests that your time is better spent finding a merchant that you trust than trying to do your own on-the-fly evaluations of what's in the display case.

Casson Trenor, Senior Markets Campaigner for Greenpeace, explained by phone that the organization rated the top 20 fish sellers in the U.S. on four attributes.

• Policy -- do they have one for issues like wild vs. farmed fish, sustainably-harvested stock, and fish caught in highly wasteful ways, such as bottom trawling?