Horseshoe Crabs Arrive in Jamaica Bay

By Don Riepe

During the last few weeks, the prehistoric horseshoe crabs have been coming ashore in Jamaica Bay to lay eggs at the high tide area – as they’ve apparently done for over 300 million years (give or take a millennium or two). To greet them, the American Littoral Society and its partners (JBRPC, NYC Audubon, and NPS) organized a festival in support of this natural event. Over 100 people came, and many brought along their children, who were in awe of this ‘living’ dinosaur. Actually the ‘crabs’ date way back in the fossil records, before the dinosaurs emerged. Also, they are not really crabs but more closely related to arachnids (spiders and scorpions).

These scary-looking but harmless animals are a very important part of the ecology of the bay as the billions of eggs they lay around the shorelines provide food for fish and other marine life, as well as thousands of shorebirds that are migrating through the city this time of year. One bird in particular, the endangered Red Knot, flies non-stop from Brazil each spring to reach its nesting grounds in the northern tundra. Jamaica Bay (and especially much larger Delaware Bay) are important stopover sites for them to ‘refuel’ on the eggs and regain the body fat needed to continue the long journey north.

The horseshoe crab is also used in medicine as its copper-based bluish blood contains an element that clots when exposed to minute traces of bacteria. This is refined in the lab and used to test the purity of vaccines and blood transfusions. So, for their ecological and medicinal values the horseshoe crab deserves our respect and protection. May they live long and prosper!