Horseshoe Crab Monitoring

Horseshoe Crab Monitoring in Hempstead Harbor

CSHH has established a monitoring site in Hempstead Harbor as part of the NY Horseshoe Crab Monitoring Network. This is a collaborative effort led by NYSDEC, Cornell Cooperative Extension of Suffolk, and Stony Brook SOMAS. Monitoring efforts are conducted across the New York Marine District, which includes all of Long Island, Fisher’s Island, and parts of NYC during full and new moon cycles through May and June (horseshoe crab mating season). Horseshoe crabs are first counted and then tagged using US Fish and Wildlife tags. This monitoring network was established to aid in conservation and management efforts of this ancient species.

Horseshoe crabs are essentially living fossils; they have survived five mass extinction events and have remained relatively unchanged for nearly 445 MILLION YEARS! They are considered a keystone species, meaning that they are vital to maintaining the health and balance of the local ecosystem. Their eggs are an important food source for the endangered red knot, a migratory bird that relies on this food source as they make their journey to the arctic to breed.

Unfortunately, horseshoe crab populations have been declining due to overharvesting for bait and biomedical purposes. Horseshoe crab meat is used as bait for whelk and eel fisheries. Their blood is copper-based, giving it a distinct blue color, and is used as a purification agent for vaccines and other medical devices. It is important to note that there is no biomedical license available in New York State.

This monitoring network helps determine how many horseshoe crabs are within the NY Marine District, and with tag deployment, migratory patterns can be determined.