Crabs Face Double Whammy: From Scientists and Birds

The AP looks at the plight of horseshoe crabs, whose blood is sought for medicine
By Newser Editors and Wire Services
Posted Aug 6, 2023 3:30 PM CDT
Crabs Face Double Whammy: From Scientists and Birds
Horseshoe crabs spawn at Reeds Beach in Cape May Court House, N.J.   (AP Photo/Matt Rourke)

A primordial sea animal that lives on the tidal mudflats of the East Coast and serves as a linchpin for the production of vital medicines stands to benefit from new protective standards. But conservationists who have been trying for years to save a declining bird species that depends on horseshoe crabs fear the protections still don't go far enough. The AP takes an in-depth look at the complicated issue.

  • The crabs: Drug and medical device makers are dependent on the valuable blue blood of the crabs—helmet-shaped invertebrates that have scuttled in the ocean and tidal pools for more than 400 million years—to test for potentially dangerous impurities. The animals are drained of some of their blood and returned to the environment, but many die from the bleeding. However, recent revisions to guidelines for handling the animals should keep more alive through the process, regulators said. Meanwhile, the animals are declining in some of their East Coast range.

  • The birds: The harvest of horseshoe crabs, which are also caught for bait in the commercial fishing industry, has emerged as a critical issue for conservationists in recent years because of the creature's role in coastal ecosystems. The crabs' eggs are vitally important food for a declining subspecies of a bird called the red knot, a rust-colored, migratory shorebird listed as threatened under the Endangered Species Act. The birds, which migrate some 19,000 miles roundtrip from South America to Canada and must stop to eat along the way, need stronger protection of horseshoe crabs to survive, said Bethany Kraft, senior director for coastal conservation with the Audubon Society.
  • The blood: The horseshoe crabs are valuable because their blood can be manufactured into limulus amebocyte lysate, or LAL, that is used to detect pathogens in indispensable medicines such as injectable antibiotics. The crabs are collected by fishermen by hand or via trawlers for use by biomedical companies, then their blood is separated and proteins within their white blood cells are processed. It takes dozens of the crabs to produce enough blood to fill a single glass tube with its blood, which contains immune cells sensitive to bacteria. There are only five federally licensed manufacturers on the East Coast that process horseshoe crab blood. The blood is often described by activist groups as worth $15,000 a quart, though the figure is difficult to verify.
  • New rules: Regulators estimate about 15% of the crabs die in the bleeding process. In 2021, that meant about 112,000 crabs died, said Caitlin Starks, a senior fishery management plan coordinator with the Atlantic States Marine Fisheries Commission. The bait fishery for horseshoe crabs, which are used as bait for eels and sea snails, killed more than six times that, she said. Still, the fisheries commission in May approved new best management practices for the biomedical industry's harvesting and handling of the crabs. Those include minimizing exposure to sunlight and keeping crabs cool and moist, Starks said. "The goal is to give the crabs that are bled a better chance of surviving and contributing to the ecosystem after they are released," she said.
(Read more here, including the push to create a synthetic substitute for the crabs' blood.)

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