A Federal Trade Commission official said today that the country’s leading seafood restaurant chains have been warned that the agency will crack down on false claims of locally caught fare, following complaints from the domestic fishing industry of misleading menus and advertising.

The U.S. imports about 80% of its seafood, according to the National Oceanic and Atmospheric Administration. But restaurants can draw in diners by marketing super-fresh seafood caught in nearby waters.

Alvaro Bedoya, an FTC commissioner, sent letters to the 10 highest-grossing seafood restaurants on Tuesday, including Red Lobster, Long John Silver’s and Legal Sea Foods, warning that false advertising about locally caught fare could be investigated, he told Reuters.

“This is a new reminder to companies that it is all of the ways you’re communicating to a consumer, the net impression of that communication needs to be accurate,” Bedoya said.

In September, the FTC issued guidance clarifying that restaurant decor, menu descriptions, and social media posts that suggest local fare could count as illegally misleading customers if the restaurant is not serving domestic seafood.

Bedoya this summer visited with shrimpers in the Gulf Coast who have seen their sector shrink in part due to competition from imports, he said.

More than 90% of shrimp imports come from India, Ecuador, Indonesia and Vietnam, according to the Southern Shrimp Alliance, which represents small- and mid-size shrimp businesses.

The group has advocated for stronger FTC enforcement because its members are struggling to compete with less expensive imports, it said in September when the FTC guidance was released.