Horseshoe crabs are harvested by the biomedical industry for their blue blood, used to test vaccines and medical devices for bacterial contamination. Approximately 30% of bled crabs die after the procedure, raising significant welfare concerns.
Horseshoe crabs bled in biomedical harvesting lose up to 30% of their blood volume and are returned to the ocean in physiologically stressed condition. Mortality rates of 25-30% represent direct killing of enormous numbers of animals per year. Surviving crabs show reduced egg production and behavioural changes suggesting prolonged physiological stress. The availability of synthetic alternatives that are equivalent in detecting bacterial contamination makes the continued use of horseshoe crab blood ethically questionable.