The Limulus amebocye lysate (LAL) assay is the industry standard for endotoxin detection.  The test derives from the bloodstream of horseshoe crabs, who are bled and returned to the water.  It is estimated that 10-30% of the crabs do not survive the bleeding process.  A recent study from New Hampshire suggests that those who do survive are afflicted with behavioral and physiological effects.  These include changes in mobility, altered behavioral rhythms and possible reductions in immune function.  These observations may contribute to the known decline in Limulus populations.

Sublethal Behavioral and Physiologic Effects of the Biomedical Bleeding Process on the American Horseshoe Crab, Limulus polyphemus