Horseshoe crabs

• Horseshoe crabs, medicinally priceless and one of oldest living creatures on the earth, appear to be disappearing from their familiar spawning grounds due to destructive fishing practices along Chandipur and Balaramgadi coast in Odisha’s Balasore district.
• Horseshoe crabs are considered living fossils meaning they have existed nearly unchanged for at least 445 million years, well before even dinosaurs existed.
• There are four species of horseshoe crabs–
  • Limulus polyphemus, the Atlantic or American horseshoe crab, found along the Atlantic coast of the United States and the Southeast Gulf of Mexico.
  • The tri-spine horseshoe crab (Tachypleus tridentatus), the coastal horseshoe crab (Tachypleus gigas) and the mangrove horseshoe crab (Carcinoscorpius rotundicauda) in coastal waters of India, southeast Asia, China and Japan
• Female horseshoe crabs are about one-third larger than the males.

Conservation Status:

• The American horseshoe crab is listed as Vulnerable to extinction and the tri-spine horseshoe crab is classified as Endangered on the IUCN Red List of Threatened Species.
• Coastal horseshoe crab (Tachypleus gigas) and the mangrove horseshoe crab (Carcinoscorpius rotundicauda) are not listed on IUCN red list yet but are part of Schedule 4 of Wildlife Protection Act, 1972.

Uses

• A horseshoe crab’s blood contains a special clotting agent limulus amebocyte lysate(LAL) which detects a contaminant called endotoxin.
• It is used to test vaccines, drugs and medical devices to ensure that they aren’t contaminated with dangerous bacterial toxins.