The American horseshoe crab, Limulus polyphemus, occupies a critical niche in both the ecology of the Delaware Bay and in human pharmacology. Each spring as the crab comes ashore to spawn, its eggs provide food for hundreds of thousands of shorebirds flying north from South America to breeding grounds in the Arctic. In human medicine, the crab is bled, with no apparent harmful effects, to procure a compound that is used by the pharmaceutical industry to test intravenous drugs for dangerous bacteria.
In 1990, Dr. Carl N. Shuster Jr, the late James J. Finn, William Hall and Benjie Swan initiated the first survey of spawing horseshoe crabs. The survey has continued yearly with the help of dedicated volunteers.