CAMPAIGNS

Protecting the Horseshoe Crab

One of the oldest living species on Earth

What are Horseshoe Crabs?

Horseshoe crabs (Limulus polyphemus) have been around for over 350 million years, having shared this planet with the dinosaurs. Many scientists refer to them as “living fossils.” Horseshoe crabs have a large dark brown shell with 5 pairs of legs, 5 pairs of gills, a spike-like tail, and bump-like eyes. Female horseshoe crabs are larger than males and can reach a total length of 2 feet, including the tail. Living as long as 20 years, horseshoe crabs reach maturity at around 10 years of age, molting as they grow. Although referred to as “crabs” they are Arthropods – more closely related to spiders than to real crustaceans such as shrimp, lobsters, and crabs.

Why are Horseshoe Crabs so important?

• Medical uses: The blood of horseshoe crabs contains a critical component, Limulus Amoebocyte Lysate, known as LAL. This unique compound clots when exposed to bacteria or bacterial endotoxins. The U.S. Food & Drug Administration requires all drugs intended for human consumption to be tested using LAL. Some medical equipment and devices including items such as IV tubing are also tested with LAL. Currently, scientists have no means to reproduce this compound synthetically; therefore horseshoe crabs are of vital importance to human drug development.
• Keystone species in the food web: Millions of shorebirds that fly 10,000 miles from South America to the Arctic, stop along our Atlantic beaches to nourish themselves on horseshoe crab eggs. Every year, horseshoe crabs lay their eggs on beaches at full and new moon high tides in late May and June. These eggs are the single most important food source for migrating shorebirds. Without a critical mass of horseshoe crabs and their eggs, migrating birds become too weak to complete their journey and successfully reproduce.
• Impacts on Local Economies: Human activities cause sharp declines in Horseshoe Crab populations, affecting local economies: It is estimated that close to $40 billion is spent annually in the United States on bird watching and wildlife viewing, with hundreds of millions being spent on the observation of shorebirds. As bird populations drop, so does the income related to bird watching and recreation.
  

Red Knot Calidris canutus

Due to significant declines in horseshoe crabs eggs, once common migrating shorebirds now face extinction. The dramatic population decline of the Red Knot and the Semipalmated Sandpiper are linked to the dramatic decline of horseshoe crab eggs.

The Red knot, a local shorebird, depends upon the rich nutrients of horseshoe crab eggs. Migrating shorebirds will fly 2000 miles at a time, 70 hours nonstop, as they head north from South America, losing up to 40% of their body weight. The birds stop for several days to feed on Atlantic beaches, where they regain much of their body weight. Once their strength and body weight are restored, the birds fly the final segment of their trip to their summer breeding grounds in Canada.

Why are horseshoe crabs disappearing?

The number of horseshoe crabs laying eggs on our beaches has declined significantly. The leading impact on horseshoe crab populations and shore bird viability is over harvesting of the horseshoe crabs. Horseshoe crabs are taken and chopped up for bait to catch eel and conch, which is sold in Asian markets in the Far East.

Connecticut Considering Horseshoe Crab Protections

The Connecticut Department of Environmental Protection (DEP) regulates the taking of horseshoe crabs in Connecticut waters. Due to the dramatic decline of horseshoe crab eggs, the DEP instated a ban on horseshoe crab harvesting in three ecologically significant areas along Long Island Sound (see photo below). The DEP has also delayed the horseshoe crab season and suspended horseshoe crab harvesting on weekends. Horseshoe crabs spawn during the month of May. Both Connecticut and New York should further protect horseshoe crabs and dependent shorebirds by enacting a statewide moratorium on taking horseshoe crabs.

In 2006, the Connecticut Department of Environmental Protection enacted a moratorium on horseshoe crab harvesting at three ecologically significant areas: Milford Point, Sandy Point and Menunketesuck Island

On Friday, June 20, 2008, CCE’s staff, led by Kasey Jacobs, CT Program Coordinator, and Maryli Secrest, Connecticut Outreach Director, volunteered for Project Limulus to help tag and release horseshoe crabs.

Project Limulus is:

• A study examining the ecology of the Long Island Sound horseshoe crab (Limulus polyphemus) population.
• A community-based research program providing opportunities for all people to become active contributors to ongoing scientific research.
• A data-gathering network to potentially direct conservation programs for the horseshoe crab
• An educational tool to increase public awareness of Limulus and its connection to the Long Island Sound ecosystem and human health.

For more information about Project Limulus visit www.projectlimulus.org.

Project Limulus Volunteer Day Photo Gallery:

For more information on horseshoe crabs or efforts to protect this ancient species, please contact CCE's White Plains office at: (914) 997-0946 or CCE’s New Haven office at (203) 785-9080.

Updated by kjacobs 6/25/08