Blue blood from horseshoe crabs is needed for medicine, but a declining bird relies on crabs to eat

Susan Linder, a horseshoe crab egg density team leader with the Horseshoe Crab Recovery Coalition examines a crab during an interview with The Associated Press on June 13 at Reeds Beach in Cape May Court House, N.J. (AP Photo/Matt Rourke)

PORTLAND, Maine — The horseshoe crab has been scuttling in the ocean and tidal pools for more than 400 million years, playing a vital role in the East Coast ecosystem along with being a prized item for fishing bait and medical research.

Its blue blood is harvested for medical researchers and used by drug and medical device makers to test for dangerous impurities in vaccines, prosthetics and intravenous drugs. The crabs are used by fishing crews as bait to catch eels and sea snails. And their eggs are a critical food for a declining subspecies of bird called the red knot – a rust-colored, migratory shorebird listed as threatened under the Endangered Species Act.


The competing interests have set up a clash among researchers, fishing crews and environmentalists over new protections designed to keep more of the crabs in the environment. The animals are drained of some of their blood and returned to the shore, but many die from the bleeding. And a drive to create synthetic alternatives has yet to succeed in phasing out the crabs from use.

Recent revisions to guidelines for handling the animals should keep more alive through the process, regulators said. The animals — not really true crabs but rather more closely related to land-dwelling invertebrates such as spiders and scorpions — are declining in some of their East Coast range.

“They were here before the dinosaurs,” said Glenn Gauvry, president of Ecological Research &Development Group, a Delaware-based nonprofit that advocates for horseshoe crab conservation. “And they’re having problems because the new kids on the block, us, haven’t learned to appreciate the elders.”

The harvest of horseshoe crabs has emerged as a critical issue for conservationists in recent years because of the red knot. The birds, which migrate some 19,000 miles (30,577 kilometers) 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.

Kraft and other wildlife advocates said the fact the guidelines for handling crabs are voluntary and not mandatory leaves the red knot at risk.

“Making sure there is enough to fuel these birds on this massive, insanely long flight is just critical,” Kraft said.

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