457 



Effects of blood extraction on horseshoe crabs 

 iLimulus polyphemus) 



Elizabeth A. Walls 



Department of Fisheries and Wildlife Sciences 

 Virginia Polytecfinic Institute and State University 

 Blacksburg, Virginia 24061-0321 

 Present address: Center for Environmental Studies 



Virginia Commonwealth University 



1000 West Cary Street, Box 843050 



Richmond, Virginia, 23284 



Jim Berkson 



Department of Fisheries and Wildlife Sciences 

 Virginia Polytechnic Institute and State University 

 Blacksburg, Virginia 24061-0321 

 E-mail address (for J Berkson. contact author); |berkson@vt.edu 



the United States, mandated that all 

 biomedical companies actively bleed- 

 ing horseshoe crabs estimate mortal- 

 ity rates resulting from their bleeding 

 process (Schrading et al.'^). Because of 

 the unique methods of the different 

 biomedical companies, each company 

 was required to quantify its own rate 

 of mortality. 



BioWhittaker, a CAMBREX com- 

 pany, is the largest producer of LAL. 

 In response to the ASMFC mandate, 

 BioWhittaker requested that Virginia 

 Tech conduct the mortality study for 

 their company. Our objective was to 

 determine horseshoe crab mortality 

 for a two-week period following the 

 bleeding process. 



Methods 



Horseshoe crabs ILimulus polyphemus) 

 are caught by commercial fishermen for 

 use as bait in eel and whelk fisheries 

 ( Berkson and Shuster, 1999) — fisheries 

 with an annual economic value of $13 

 to $17 million (Manion et al.M. Horse- 

 shoe crabs are ecologically important, 

 as well (Walls et al., 2002). Migratory 

 shorebirds rely on horseshoe crab eggs 

 for food as they journey from South 

 American wintering grounds to Arctic 

 breeding grounds (Clark, 1996). Horse- 

 shoe crabs are also essential for public 

 health (Berkson and Shuster, 1999). 

 Biomedical companies bleed horse- 

 shoe crabs to extract a chemical used 

 to detect the presence of endotoxins 

 pathogenic to humans in injectable and 

 implantable medical devices (Novitsky, 

 1984; Mikkelsen, 1988). Bled horseshoe 

 crabs are returned to the wild, subject to 

 the possibility of postbleeding mortal- 

 ity. Recent concerns of overharvesting 

 have led to conflicts among commercial 

 fishermen, environmentalists acting on 

 behalf of the shorebirds, and biomedi- 

 cal companies (Berkson and Shuster, 

 1999; Walls etal., 2002). 



In order to create an effective, sus- 

 tainable management policy for the 

 horseshoe crab resource, the comple- 

 tion of a stock assessment that incor- 

 porates human-induced mortalities is 

 necessary. A stock assessment is not 

 currently available because of a lack of 

 critical information on the horseshoe 

 crab population (Berkson and Shuster, 



1999). One critical piece of information 

 needed is an estimate of the mortali- 

 ties involved in the biomedical bleed- 

 ing process. With an estimated 260,000 

 horseshoe crabs bled in 1997 (HCTC2), 

 the last year with data available, mor- 

 talities may not be negligible. 



Five biomedical companies on the At- 

 lantic coast of the United States bleed 

 horseshoe crabs in the laboratory for 

 the production of Limulus Ameobocyte 

 Lysate (LAL). The horseshoe crabs are 

 caught by fishermen under contract to 

 biomedical companies, bled, then re- 

 turned to their point of capture. 



The LAL test used to detect endo- 

 toxins in humans is derived from the 

 blue, copper-based blood of the horse- 

 shoe crab. Although alternate tests 

 exist for the detection of endotoxin, the 

 LAL test is the most effective because 

 it is capable of detecting as little as 

 one millionth of a billionth of a gram of 

 endotoxin (Mikkelsen, 1988). The LAL 

 test is now a standard test used to pro- 

 tect human health around the world, 

 and horseshoe crabs are the sole source 

 of LAL. 



Each biomedical company maintains 

 its own procedures for harvesting 

 horseshoe crabs, extracting the horse- 

 shoe crabs' blood, releasing the bled 

 horseshoe crabs, and developing the 

 LAL substance. In 1998, the Atlantic 

 States Marine Fisheries Commission 

 (ASMFC), the Commission responsible 

 for horseshoe crab management in 



We compared mortality rates between 

 horseshoe crabs that underwent the 

 bleeding process (bled) and horseshoe 

 crabs that were suitable to undergo 

 the bleeding process but were not 

 bled (unbled). Throughout the 1999, 

 2000, and 2001 bleeding seasons 

 (June through August), BioWhittaker 

 obtained horseshoe crabs by trawling 

 in the Atlantic Ocean off the coasts of 

 Chincoteague, Virginia, or Ocean City, 

 Maryland (or off both coasts). After 

 capture, the horseshoe crabs were 

 brought to BioWhittaker's bleeding 



' Manion, M. M., R. A. West, and R. E, Uns- 

 worth. 2000. Economic assessment of 

 the Atlantic coast horseshoe crab fishery, 

 71 p. Division of Economics, U.S. Fish 

 and Wildlife Service, Arlington, VA. 



2 HCTC (Horseshoe Crab Technical 

 Committee). 1998. Status of the horse- 

 shoe crab {Limulus polyphemus) popula- 

 tion of the Atlantic coast, 9 p -t- figures and 

 tables. Horseshoe Crab Technical Com- 

 mittee, Atlantic States Marine Fisheries 

 Commission. Washington, D.C. 



3 Schrading, E., T. O'Connell, S. Michels, and 

 P. Perra. 1998. Interstate management 

 plan for horseshoe crab, 59 p. Atlantic 

 States Marine Fisheries Commission, 

 Washington D.C. 



Manuscript accepted 6 November 2002. 



Manuscript received 9 January 2003 at 

 NMFS Scientific Pubhcations Office. 



Fish. Bull. 101:457-459 (2003). 



