Population Studies of Horseshoe Crab (Limulus polyphemus) in Delaware Bay
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UPDATE : Papers, Reports, and Presentations International Symposium on Science and Conservation of Horseshoe Crabs
Cooperative Horseshoe Crab Tagging Study Spatial Simulation of Horseshoe Crab Spawning and Egg Disturbance Delaware Bay Horseshoe Crabs Tagged to Study Migration, Survival, and Abundance With help from Delaware Bay watermen, over 17,000 horseshoe crabs were tagged before and during this year�s spawning run. Recaptures of tagged horseshoe crabs will help determine migration patterns, abundance, and survival. Please look for and report tagged horseshoe crabs. Record tag number(s), where and when you recovered the tag, whether the crab was alive when found, and whether it was released. Report the information to the Fish and Wildlife Service using the toll-free phone number that is printed on the tag (1-888-LIMULUS) or contact Dave Smith at 304-724-4460 or david_r_smith@usgs.gov. Those reporting tags will be sent information detailing when and where the animal was released, a certificate of appreciation, and a pewter pin in the shape of a juvenile horseshoe crab. This study is a cooperative effort involving the U.S. Geological Survey, U.S. Fish and Wildlife Service, New Jersey Division of Fish, Game, and Wildlife, and Delaware Department of Natural Resources. Figures showing possible locations of tags and tag types. The drawing on the left shows four possible tag types. (Note that an actual horseshoe crab will have only one or two of the tags shown.) The tag types are A) Radio tag, B) Glued tag, C) Round button tag, D) Squarish button tag.The photo on the right shows a female being released with a radio tag and a round button tag. Introduction to the horseshoe crab While horseshoe crabs (Limulus polyphemus) are familiar to anyone who has spent some time on Atlantic coast beaches, they are, in fact, relicts of an ancient class of arthropods most members of which have been extinct for hundreds of millions of years. Besides being considered "living fossils," horseshoe crabs are of special interest because their eggs, billions of which are laid each spring on protected sandy shores like Delaware Bay, provide vital nourishment for hundreds of thousands of migrating shorebirds. The annual spectacle of horseshoe crab spawning and bird feeding, which peaks during the full and new moons of May and June, attracts bird watchers to Delaware Bay from far and wide. Red knot (Calidris canutus), sanderling (Calidris alba), ruddy turnstone (Arenaria interpres), and semipalmated sandpiper (Calidris pusilla) are just a few of the species that depend on the horseshoe crab eggs to sustain their long flights from South America to their breeding grounds in the Arctic. Moreover, horseshoe crabs are a source of food for threatened loggerhead sea turtles (Caretta caretta), and horseshoe crab eggs are consumed by a variety of juvenile fishes. People also depend on the horseshoe crab. Horseshoe crab blood is collected to produce an important pharmaceutical called Limulus amoebocyte lysate (LAL), which is used to test for human pathogens in human blood, tissues, and intravenous drugs. Although the crabs are released alive after a small sample of their blood is taken, it is estimated that mortality is increased by 10 to 15% after release. Of more concern is the increasing demand for horseshoe crab for use as bait in the American eel and whelk fisheries. Inconclusive evidence suggests that horseshoe crabs are being over-fished and are in decline in Delaware Bay. USGS/State Partnership Program The horseshoe crab study is one of several USGS/State cooperative projects that have been supported during 1999. The USGS State Partnership Program is a competitive funding initiative that seeks to foster collaboration among scientists and resource managers from States, Tribes, the USGS, and other Department of the Interior agencies. The overall goal of the State Partnership Program is to improve scientific understanding and information dissemination in support of effective management and conservation of the Nation's biological resources. Dr. Gary Brewer coordinates the USGS State Partnership Program for 22 states in the eastern U.S. USGS Science Support Program In Fiscal Year 2001, Congress appropriated funds to create the Science Support Program to be administered by the Biological Resources Discipline (BRD) of the U.S. Geological Survey (USGS).  Under this program, the Fish and Wildlife Service (FWS) posts its needs for research under the Endangered Species Act.  Scientists within USGS prepare proposals that address those needs, and compete for the funds available under this program.  Annually, a panel comprised of members of the FWS and the USGS (BRD) determine which proposals best meet the research needs of the FWS.  Dr. Greg Smith coordinates the USGS Science Support Program. USGS As the nation's largest water, earth and biological science and civilian mapping agency, the USGS works in cooperation with more than 2000 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, contribute to sound economic and physical development of the nation's natural resources, and enhance the quality of life by monitoring water, biological, energy, and mineral resources.		Delaware Bay Horseshoe Crab Spawning Survey UPDATED: Download SPAWNAR - the Horseshoe Crab Spawning Activity Results program for Delaware Bay for 1999-2004. (Funded by the Delaware Estuary Program with cooperation from the Delaware Divsion of Fish & Wildlife.) Would you like to volunteer for the spawning survey? Survey results from 1999 to 2004 Spawning Survey Protocol Partners Project Updates Project reports and publications For additional information contact David Smith Other Links This page is included in The Virtual Library of Biodiversity and Ecology a portion of the Center for Conservation Biology Network Everything you wanted to know about horseshoe crabs but were afraid to ask. Thanks to the creative minds at Warner Elementary School Check out the wonderful web page about horseshoe crabs in the Yamaguchi Bay and Aio Bay, Japan. Thanks to the inquisitive minds at the Aio Junior High School Science Club. Be sure to check out their really cool paper craft models of horseshoe crabs and trilobites (Horseshoe crab origami) An award winning page on horseshoe crabs. Thanks to the dedication and hard work of Glenn Gauvry and the Ecological Research and Development Group (ERDG)

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