Case Studies in Fisheries Conservation and Management: Applied Critical Thinking and Problem Solving
Case 13: Horseshoe Crabs: A Struggle Among User Groups
Late Triassic Period (about 200 million years ago), at what will someday be the East Coast of the United States:
The mountains far in the distance are jagged and steep, hav¬ing only recently broken through the earth. The climate is quite warm and the air smells slightly like methane. A large dinosaur pushes slowly through the cycad trees, flattening ferns with its long tail. Like other prosauropods, this 30-foot long Ammosaurus has a long neck, allowing it to graze high in the tree tops. A small group of theropods dash past on the mudflats, hungrily eying the Ammosaurus. Luckily for the grazer, it is too large for this group of skilled hunters to eat (Weishampel and Young 1996). As night falls and the tide rises, another strange creature emerges from the water. Thousands of animals that resemble helmets crawl onto the beach to spawn before returning to the depths of the ocean. These horseshoe crabs pay no attention to the dinosaurs; this species was here about 50 million years before the dino¬saurs appeared.
For 250 million years, horseshoe crabs Limulus polyphemus have conducted their annual pilgrimage to spawn on sandy beaches, particularly in the Delaware Bay. But, in recent years, their numbers have been dwindling, worrying the multiple groups that rely on this species. On the Atlantic coast of the United States, horseshoe crabs are commercially harvested for bait, are used by the biomedical industry, and are an important source of food for a large number of species including migrating shorebirds (Berkson and Shuster 1999).
Management of horseshoe crabs is an attempt to balance the requirements of these user groups. However, the needs of these groups are often difficult to reconcile, and value judgments and compromises may be needed. This case study describes the needs of these primary stakeholders in more detail and includes position statements about horseshoe crab management in Virginia from a member of a conservation advocacy group and a member of the seafood packing industry.