Horseshoe crabs are harvested alive for their blood's unique bacterial detection properties, raising welfare concerns as populations decline in parts of their range.
Horseshoe crab welfare during biomedical bleeding involves prolonged restraint, out-of-water handling, and blood extraction that may cause physiological stress. The 10-30% post-bleeding mortality rate means hundreds of thousands of individual animals die annually from the harvest process, and surviving animals may show behavioral and reproductive impairments. The ecological impact of population decline affects not only individual crabs but the shorebirds that depend on horseshoe crab eggs for critical fueling during spring migration. The availability of synthetic alternatives (recombinant factor C) that do not require horseshoe crab blood creates an opportunity to eliminate biomedical harvest while maintaining medical safety standards, but industry adoption has been slow despite regulatory approval.