Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Phase II, Virginia Polytechnic Institute and State University
Blacksburg, VA, USA
The "American" horseshoe crab (Limulus polyphemus) is a unique marine organism that has served as a laboratory research model to study the structure, function, embryology and physiology of invertebrates. Horseshoe crabs can be maintained in a wide variety of systems ranging from glass aquaria to large fiberglass tanks with various types of mechanical and biological filtration systems. Some systems may also employ protein skimmers, UV filtration units, and ozonation to help reduce potentially harmful bacteria from the water. Adult horseshoe crabs are tolerant of a wide range of environmental conditions, ranging in temperatures from -5°C to 35°C and salinities from 5 ppt to 35 ppt, with optimal temperatures between 15°C and 21°C and salinity around 27 ppt. In captivity, horseshoe crabs are commonly fed dead fish, squid, small crabs, clams and frozen brine shrimp. Horseshoe crabs also readily consume commercially-prepared artificial shrimp/fish diets, but the long-term nutritional value of these synthetic formulations is not known.
Though the horseshoe crab has been used for many years as a laboratory animal, few reports exist describing their diseases or syndromes. Non-infectious problems range from water quality problems to developmental problems and traumatic injuries. Infectious etiologies include algae, fungus, colonial and filamentous cyanobacteria, gram (-) negative bacteria and a variety of protozoan and metazoan parasites. Clinical evaluation of a horseshoe crab can be problematic as the hard, non-transparent carapace makes examination and sample collection difficult. In addition, very little is known concerning the treatment and medical management of horseshoe crabs, though a few external treatments have been suggested to remove ectocommensals and external parasites.
1. Smith SA, JM Berkson, RA Barratt. 2002. Horseshoe crab (Limulus polyphemus) hemolymph, biochemical and immunological parameters. Proceedings of the International Association for Aquatic Animal Medicine. 33:101-102.
2. Smith SA, JM Berkson. 2005. Laboratory culture and maintenance of the horseshoe crab (Limulus polyphemus). Lab Animal 34:27-34.