Regardless of their widespread identify, horseshoe crabs are usually not actually crabs (crustaceans), however are extra intently associated to spiders and scorpions. Atlantic horseshoe crabs (Limulus polyphemus), which swarm U.S. coastlines every summer season from Maine to Mexico, have been known as “dwelling fossils” as a result of they predate the dinosaurs by greater than 200 million years. Their easy, laborious shell (exoskeleton) is formed like a horseshoe (thus the identify). They use their lengthy tails as rudders within the water and to flip themselves in the event that they get overturned on the seashore. They’re large reworkers of sediments and feed on a wide range of marine worms and invertebrates, together with some commercially vital fish.

Few folks notice how vital horseshoe crabs are to fashionable medication. As a result of their blue, copper-based blood shortly clots within the presence of bacterial toxins, medical researchers use it to check intravenous medicine, vaccines, and medical units, guaranteeing that they’re freed from bacterial contamination. Yearly, many 1000’s of horseshoe crabs are harvested from their habitats, “bled” of about one-third of their blood, then returned to the seashore comparatively unhurt.

Horseshoe crabs are also vital ecologically. Greater than 20 species of migratory birds, loggerhead sea turtles, and a myriad of business and recreation fish and crab species depend on the crabs’ eggs as an annual boon to their diets.

Whereas Atlantic horseshoe crab numbers had been declining within the Nineties, populations are recovering because of the regional administration efforts of the states by way of the Atlantic States Marine Fisheries Fee. Delaware Bay has the most important inhabitants of horseshoe crabs on the earth, and scientists from NOAA’s Nationwide Estuarine Analysis Reserves System assist conduct annual horseshoe crab spawning surveys, which is a Delaware Bay-wide effort. Nonetheless, habitat loss and excessive demand as industrial bait are nonetheless considerations for horseshoe crabs and migratory shorebirds.