The Decline of the Horseshoe Crab in the Long Island Sound

The Long Island Sound is a home to many different marine and coastal species of animals and plants. This biodiversity is part of an ecological balance and provides ecosystem services. Not only are some these species important for the environment, but they can also be important for human health and research. Limulus polyphemus, the American horseshoe crab, is one of the oldest living organisms in the Long Island Sound and is known as a ‘living fossil’. Although adult horseshoe crabs have only a few predators, their eggs are an important part of shorebird and fish diets. Horseshoe crabs also aid human health because their blood products are used to test all vaccines for bacterial contamination. In this study, conducted spawning surveys at night two days before a full moon, the night of a full moon and two days after the full moon at Milford Point. Additional surveys were conducted on at least 15 beaches along the CT coastline. The results showed that the number of spawning horseshoe crabs has has declined, while the number of single females is increasing. This species is not reproducing at its maximum potential and the management practices of the State need to be changed