Delaware has joined New Jersey in imposing a two-year moratorium on the capture of horseshoe crabs. Horseshoe crabs are used as bait in whelk fishing. The moratorium is designed to help horseshoe crabs recover to their numbers in the 1980s and 1990s, before horseshoe crab fishing became popular.
Their eggs are essential food for migrating shorebirds, particularly red knots. Thousands of red knots stop along the Delaware Bay each May to rest and refuel before completing the last leg of their annual migration from their winter home in South America to their breeding grounds in the Arctic. Red knot migration is timed to coincide with the spawning of horseshoe crabs, which come ashore to mate and lay their eggs. Red knots have declined in recent years thanks to overfishing of their main food source at this critical migration stop. The rate of decline suggests that they could be extinct by 2010 without intervention.