When I pick up a bag of frozen salmon labeled "sustainably farm-raised," I assume someone has checked that claim. It turns out no one has to. According to Laura Lee Cascada of the Aquaculture Accountability Project, words like "sustainable" and "responsible" aren't legally defined for U.S. seafood, so companies can print them without proving anything.

A new class-action lawsuit shows what that gap can hide. Filed late last month in an Illinois federal court, it says Mama Bear frozen salmon comes from Australis Seafoods, a Chilean producer that allegedly keeps 74% of its salmon pens inside protected parks and reserves in Patagonia. The complaint accuses the operation of raising more fish than its permits allow, polluting nearby waters badly enough to cause oxygen-starved dead zones, releasing drugs and waste into the sea, and packing fish so tightly that disease spread. It also connects the deaths of two whales to entanglement in the company's nets. None of this has been decided in court, and the companies did not answer a reporter's questions.

This goes beyond one brand. Shoppers pay extra for food they believe is better for the planet, and farmers who truly invest in cleaner practices lose out when anyone can use the same words for free. Lawyers at Lewis & Clark Law School have argued that the Food and Drug Administration (FDA), which oversees seafood, should spell out what these terms mean and make companies back them up.

I'm asking the FDA to set clear, enforceable definitions for "sustainable," "responsible" and "humane" on seafood labels, and to require proof before any company uses them. That isn't a partisan idea. It's truth in advertising.

Sign the petition to tell the FDA that a sustainability label should mean something, before more shoppers pay extra for a promise nobody checked.