The U.S. Department of Commerce has told Virginia it must slash its catch of horseshoe crabs or face a statewide moratorium on the catch of the ancient sea creature.

The closure will go into effect in mid-September unless the state agrees to comply with quotas set by the Atlantic States Marine Fisheries Commission earlier this year.

It would be the first time that a moratorium was ordered under a 1993 law that gives the Secretary of Commerce the power to close fisheries in states that fail to enforce limits set by the ASMFC, a panel representing all East Coast states that manages migratory species.

“We are still hopeful that Virginia will join the other coastal states in protecting horseshoe crabs, but if not, we are prepared to act,” said Penny Dalton, fisheries director for the National Oceanic and Atmospheric Administration, a part of the Commerce Department. “By choosing to ignore the quota, Virginia is jeopardizing the livelihood of those who depend on the crab.”

The ASMFC earlier this year approved, on a 14-1 vote, a 25 percent reduction in the coastwide catch of horseshoe crabs. Virginia was the only state opposing the reduction.

The action was aimed not only at protecting the crab, a species that has been around for 250 million years, from increased fishing pressure, but also migratory shorebirds that feed on their eggs during migration.

Virginia officials contend that the ASMFC did not have adequate scientific information to order the reduction. The state would be hard hit because the reduction was measured from an average catch between 1995-97, before Virginia’s landing of the crabs began rising as other states cut their harvests.

As a result, Virginia’s allocation was cut to 152,498 from its 203,326 baseline — but its catch had surpassed 1 million in 1998. The Virginia Marine Resources Commission, which argues that it has to use “sound science” to set catch limits unless directed otherwise by the General Assembly, set this year’s harvest at 710,000 crabs.

In June, the ASMFC found the state out-of-compliance with the management plan, sending the issue to the Commerce Department for action.

In July, the VMRC responded by slashing this year’s quota to 355,000 crabs, but that failed to head off the Commerce Department’s warning, which was issued Aug. 8.

Virginia officials are worried because horseshoe crabs are used as bait in its valuable conch and eel fisheries.

On the other hard, as fishing pressure has increased in the past decade, concerns have grown that stocks of the slow-to-mature creature are in decline. The crabs lay their eggs along the Mid-Atlantic coastline and in Chesapeake Bay during the spring, coinciding with the northward migration of red knots, sanderlings and other shorebirds that rely on the eggs for fuel during their long flights from South America to the Arctic.

Blood from the horseshoe crabs is also used by the pharmaceutical industry to test drugs and equipment for bacterial infections. After the blood is drawn, the crabs are returned to the sea alive.

Meanwhile, Commerce Secretary Norman Mineta also announced Aug. 8 that the department would soon formally propose a year-round horseshoe crab sanctuary off the mouth of Delaware Bay, where the crabs congregate before spawning. The action would prohibit anyone from catching crabs in an area approximately 60 nautical miles long by 30 nautical miles wide.

“Today we are proposing a ‘no-take’ zone for horseshoe crabs,” he said. “The last thing any of us wants is to see these creatures wind up on the fished-out stocks list.” If approved after a public comment period, the sanctuary could take effect Oct. 30.