The National Marine Fisheries Service is considering a ban on fishing for horseshoe crabs in federal waters up to 30 miles from the mouth of Delaware Bay to provide additional protection both for the crabs and declining populations of migratory shorebirds, which rely on mid-Atlantic beaches for an abundant supply of horseshoe crab eggs during migratory stopovers.

As most coastal states have cut back on their horseshoe crab harvest in recent years, much of the fishing effort has moved beyond the 3-mile limit of state management authority and into federal waters.

The federal closure had been recommended by the Atlantic States Marine Fisheries Commission earlier this year because a large portion of the Virginia landings were taken from federal waters, effectively evading voluntary catch restrictions in Maryland, Delaware and New Jersey.

The NMFS, a part of the Department of Commerce’s National Oceanic and Atmospheric Administration, said it was proposing rules to create the 1,800-square-mile sanctuary out of concern for both the increase in reported landings and the well-being of shorebirds.

Horseshoe crabs live on the continental shelf, but move inshore during the spring to spawn on beaches.

The NMFS hopes to implement its rule later this year, although that will be too late to affect this year’s catch.