USGS and other biologists note that if the horseshoe crab population were to become seriously depleted, recovery might require decades. Though prolific in terms of egg production, horseshoe crabs are long-lived animals which do not breed until they reach nine or 10 years of age.
A Cooperative Response
With concerns over horseshoe crabs mounting, ecologist Dr. Joe Margraf and colleagues at the USGS Maryland Cooperative Fish and Wildlife Research Unit began a study in 1996 to determine how horseshoe crab use of spawning beaches varies through time and space. Their goal was to develop a rigorous sampling method for use in population monitoring. The researchers found that, to be most representative and consistent, surveys should be concentrated in the shallowest waters and should be carried out on the higher of the two daily high tides, immediately following a new or full moon.
In 1998, the Atlantic States Marine Fisheries Commission implemented a management plan for the species along the Atlantic Coast. Adopted last October, the plan calls for the collection of information necessary to manage the horseshoe crab fishery and to insure protection for the diverse animals that rely on horseshoe crabs and their eggs for food. The plan also specifically mandates that the bay states of New Jersey, Delaware and Maryland develop and implement statistically sound methods for monitoring the status of horseshoe crab populations.
This interstate management plan led to the current cooperative research
program involving USGS scientists, resource managers from the three states,
and outside researchers. Under D
Contact: Gaye Farris
United States Geological Survey