More than 200 scientists say Congress should protect federal sustainable fishing laws in advance of a key hearing about the future of the way the government manages fisheries.

The Senate commerce committee is holding a hearing on Tuesday about reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act. The act is the main law governing U.S. fisheries.

The scientists are led by Andrew Rosenberg of the Union of Concerned Scientists and they sent a letter to Congress today. They say they are opposed to “legislative efforts that would weaken science-based management of U.S. marine fish populations.”

The scientists say they support preventing overfishing through the use of catch limits that are based on sound science. They’re concerned about proposals they say would weaken or eliminate such requirements.