CHEMICAL FROM THE CONTROVERSIAL HORSESHOE CRAB VITAL TO HUMAN HEALTH
30 January 2002 - Virginia Polytechnic Institute and State University

"Fishermen catch horseshoe crabs for use as bait in the lucrative eel and conch fishery," he explains. "Biomedical companies catch and bleed horseshoe crabs to produce a chemical used to detect the presence of bacteria in injectable drugs and implantable devices. Environmentalists are concerned because migratory shorebirds depend on horseshoe crab eggs to fuel their migration to their arctic breeding grounds each year. The battle over this ecologically, economically, and medically essential species has become one of the most heated environmental issues on the east coast in recent years."

In response for the need of data so that officials will know how to manage such a vital resource, Virginia Tech’s College of Natural Resources expanded its horseshoe crab research this year and built a new facility at its Aquaculture Center devoted to horseshoe crab studies. Capable of holding more than 200 adult crabs, the Horseshoe Crab Research Center is the largest captive system in the nation dedicated to horseshoe crabs.

Working in partnership with Virginia Tech are three federal agenciesinvolved in horseshoe crab research and management; state agencies responsible for horseshoe crab management in Virginia, Delaware, and Maryland; biomedical companies, including BioWhittaker, the largest producer of the LAL chemical from the crabs; and environmental groups involved in the issue such as the Audubon Society.

In the midst of the controversy, resource agencies have been forced to make critical management decisions in the absence of needed data. Because the horseshoe crab is so important, Virginia Tech’s new Horseshoe Crab Research Center has been established to provide information necessary to improve management of the species. "We founded the center on the belief that developing effective management strategies requires an understanding of all three dimensions of the horseshoe crab issue: fisheries, shorebirds, and biomedical companies," Berkson emphasizes.

Despite being more than five hours from the coast in the Appalachian mountains, Virginia Tech realized it had a unique set of assets to take the nation’s lead in the horseshoe crab study. Virginia Tech is the only institution in the nation with the combination of expertise, facilities, and experience to cover all three dimensions of the horseshoe crab issue.

The HCRC combines faculty, students, facilities, and expertise from Virginia Tech’s Department of Fisheries and Wildlife Sciences and Conservation Management Institute in the College of Natural Resources, Virginia-Maryland Regional College of Veterinary Medicine, and the new Virginia Bioinformatics Institute.

Current Research
Berkson notes that the HCRC is quickly becoming recognized as the country’s premiere horseshoe crab research institution with ongoing research funded by BioWhittaker, Inc; Virginia Sea Grant, the National Fish and Wildlife Foundation, the Atlantic States Marine Fisheries Commission, and the states of New Jersey, Delaware, and Maryland.

"Since September 11 the center has received a lot of attention because of the work we're doing with horseshoe crabs indirectly relating to counter-terrorism," Berkson points out. The chemical that comes from the blood of horseshoe crabs, LAL, is used to test for the presence of endotoxins in injectable drugs and implantable devices. That means all vaccines, including the anthrax and small pox vaccines, have to be tested using LAL to prevent any contamination, whether intentional or unintentional.

"The recent rush to produce sufficient anthrax and smallpox vaccine really shows how much we depend on LAL and the horseshoe crabs needed to produce it," Berkson explains. "At our new Horseshoe Crab Research Center we are working to develop

alternative ways to produce LAL to ensure its ongoing supply. This is extremely important because we still do not have the information we need to develop effective management regimes and the population of horseshoe crabs may be in a long term decline."

Berkson was asked to make a presentation on the topic to Virginia Governor Gilmore's Commission on Security and Preparedness (the terrorism task force) and also gave a similar presentation to the Chesapeake Bay Commission in early January. State

Senator Bolling, chair of Virginia's Environmental Commission has led Virginia’s interest in the topic.

"We do have results from a number of our studies at this point," Berkson says. "We have found that the mortality of horseshoe crabs that undergo the biomedical bleeding process is only 7.5 percent. That is astounding considering how much blood is taken out of the crabs. We would expect it to be much higher. This may be an indication of how the crabs have survived for 350 million years."

Berkson adds, "We also have new information on where horseshoe crabs are found in the ocean, how far they migrate, and the presence of possible nursery grounds, where juveniles are at particular risk from the commercial fishery."

Included in the wide variety of research projects currently being conducted are the following:

HCRC researchers are designing coastwide trawl surveys that could be used to track population changes over time. This research was considered the most important horseshoe crab research by the Horseshoe Crab Technical Committee of the Atlantic States Marine Fisheries Commission.

In another project, researchers are testing the feasibility of flying over spawning beaches using video cameras with nightscopes to index the number of spawning horseshoe crabs in the spring. If feasible this technique could supplement time consuming, manpower intensive beach surveys that have proven less than reliable over time.

Researchers are estimating the survival rates of horseshoe crabs after the biomedical industry’s bleeding process. It was not known whether the bleeding process causes large numbers of mortalities or not.

Horseshoe crabs are being tagged and released annually to provide information on movement patterns. This study is providing helpful information on the distribution of the horseshoe crab population.

Researchers are analyzing the sex and age composition of the catch of horseshoe crabs providing information needed for effective horseshoe crab management.
HCRC researchers are also looking at the biological relationship of the horseshoe crab to other species such as scorpions, blue crabs, and lobsters using new, advanced techniques.

Scientists are studying the relationship between the percentage of blood extracted per horseshoe crab to the likelihood of mortality in the animal. The goal is to develop guidelines so that biomedical companies would limit the amount of blood extracted to reduce mortality rates in the bleeding process.

Researchers are also looking at the potential of culturing the cells that produce LAL. If possible this could eliminate the need to catch horseshoe crabs for bleeding by the biomedical industry.

Other studies currently being developed including studies on shorebird-horseshoe crab interactions, horseshoe crab telemetry, and genetic studies to be conducted by the HCRC’S newest partner, the Virginia Bioinformatics Institute.

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