WASHINGTON » Experts and advocates are urging Congress to improve conditions for hundreds of foreign fishermen working in Hawaii’s commercial fleet, following an Associated Press investigation that found the men have been confined to vessels for years without basic labor protections.

The AP report found commercial fishing boats in Honolulu employ men from impoverished Asian nations who catch ahi tuna and other seafood sold nationwide. A legal loophole allows them to work on U.S-flagged boats without visas as long as they don’t set foot on shore.

Mark Lagon, a scholar at Georgetown University’s Walsh School of Foreign Service, said the fishermen are treated like modern-day slaves.

He and other speakers at a congressional forum today urged Congress to close the loophole that allows workers to stay on the boats without coming ashore.