American Horseshoe Crab

• fisiologíaIts blood is blue and contains a compound (amoebocyte lysate) the pharmaceutical industry uses to detect bacterial contamination in vaccines.
• It is not a crab: it is a chelicerate, more closely related to spiders and scorpions than to crustaceans, and its lineage has gone some 450 million years almost unchanged.
• Its blood is blue because it carries oxygen with haemocyanin, which is copper-based, instead of haemoglobin.
• That blood underpins pharmaceutical safety worldwide. In the 1950s it was found to clot on contact with bacterial endotoxins, and from that came the LAL test, used since the 1970s to check that vaccines, injectable medicines and medical equipment are free of contamination.
• Some 500,000 individuals are caught and bled every year on the east coast of the United States alone. Although they are returned to the sea, there is mortality, and that pressure is one of the causes of the species' decline.
• A synthetic alternative already exists, recombinant factor C, which avoids using animals.
• Its eggs are a key resource in wader migration: the red knot depends on them to rebuild fat halfway through its journey to the Arctic.

Habitat and environment

Soft bottoms and shallow bays of the North American Atlantic and the Gulf of Mexico; in spring it comes ashore en masse on sandy beaches to spawn on the spring tides

Sexual maturity

Matures at around 9 or 10 years old

Sources consulted: Wikipedia (es): Limulus polyphemus

The pins mark the parks and dive sites where its presence is documented.