Horseshoe Crabs: Protecting the Animals that Have Helped Protect Us

An Ecosystem on the Verge of Crashing

So, what do birds have to do with horseshoe crabs? When Bolden began his work in the quality control lab, he realized the test he was being trained to do using lysate from the crabs-referred to as a reagent-threatened their lives.

Although the process of bleeding the crabs doesn't necessarily kill them, it weakens them, impacts their mating, and canlead to death. Between harvesting their blood to test injectable medicines-roughly 70 million tests across the pharmaceutical industry each year-and fisheries using them for bait, the horseshoe population had begun to rapidly decline. The number of harvested crabs increased from 100,000 in the early 90s to more than 2.5 million by 1998.

In turn, the population of the more than 1.5 million shorebirds-including the Red Knots, a species that's part of the federal endangered list-also declined. Like many shorebirds, the Red Knots depend on horseshoe crab eggs for fuel during their treacherous migration to the Arctic to breed.

The Red Knots are especially vulnerable to their migratory journey because they're small. By the time they reach Delaware Bay, they have flown eight straight days from the coast of Brazil and count on the eggs to build up fat for the final leg of their flight.

Delaware Bay has the largest population of horseshoe crabs in the world. During their spawning season in late spring, the crabs ride the waves ashore to clunkily navigate the rocky sand and lay eggs, their sharp-looking, mini-sword tails trailing behind them.