PARENT SESSION
Oral Session # 23: Marine Ecology I: Crabs, Coral, and Lobsters.
Presiding: J Wilson
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 202.

Post-bleeding mortality of Horseshoe Crabs, Limulus polyphemus, used in the biomedical industry.

Hurton, Lenka^{*,1, 2}, Walls, Elizabeth^{1, 2}, Berkson, Jim^{1, 2}, ¹ Virginia Polytechnic Institute and State University, Blacksburg, Virginia² Horseshoe Crab Research Center, Blacksburg, Virginia

ABSTRACT- The horseshoe crab is a living fossil, whose existence can be traced back at least 200 million years. Many aspects of the ecology, life history, and physiology of the horseshoe crab are unique. The blood of the horseshoe crab is copper-based, rather than iron-based. Biomedical companies extract blood from horseshoe crabs for the production of Limulus Amebocyte Lysate (LAL). This purified extract from Limulus hemocytes is used worldwide for detecting the presence of endotoxins in medical and pharmaceutical products. The biomedical companies catch the crabs, bleed them, and then return them to the ocean. In order to better understand the persistence of the horseshoe crab, we have worked with BioWhittaker, the largest producer of LAL, to study the effects of blood loss. In the first research component, we measured the amount of blood removed from 98 male horseshoe crabs. Mean weight of blood extracted was 78.3 g. In the second component, we estimated the post-bleeding mortality rate of male horseshoe crabs from the biomedical process. Results indicate mortalities to be approximately 7.5%. In the third component, we estimated the total blood volume of horseshoe crabs over the horseshoe crab's adult size range. An average sized male horseshoe crab weighing 1 kg was found to have 251 ml of blood. Results of these studies show that despite losing an average of 31% of their blood, the post-bleeding mortality rate is quite low. The horseshoe crab has been in existence in its present form for over 200 million years. We believe that its ability to survive a significant loss of blood is one of the unique adaptations that has allowed its continued persistence, while other species have evolved and/or gone extinct through the millennia. We will discuss other physiological and ecological adaptations thought to contribute to the horseshoe crab's persistence as well.

Key words: mortality, Limulus polyphemus