An Assessment of Horseshoe Crab Breeding Habitat and Trends on Long Island, New York, 2003–2017

Limulus polyphemus, the North American horseshoe crab, is a vital member of its ecosystems and is a sentinel species in human and ecological health. In recent years, the global populations of the four horseshoe crab species have been observed to be on a decline. This investigation focuses on the sustainability of the Long Island horseshoe crab population and investigates connections with environmental, anthropogenic, and physical factors to influence horseshoe crab breeding activity. To evaluate the horseshoe crab population in light of these factors, a 15-year horseshoe crab inventory by Molloy College, CERCOM, along with NOAA buoy sea surface temperatures. Long Island land-use and geophysical changes to potential breeding sites were quantified. Results reveal that Long Island has more nonbreeding beaches than active breeding beaches, especially on the South Shore. Sea surface temperature variation fell within preferred horseshoe crab ranges; thus, temperature did not appear to be a significant influence on breeding activity. The South Shore of Long Island exhibits more recreational spaces that are used during horseshoe crab breeding months than the North Shore. Potential breeding areas are generally decreasing on Long Island by approximately 3%. Horseshoe crab potential breeding areas are subject to human disturbances and the number of breeding beaches has been observed (Tanacredi 2020) as declining. This investigation recommends specific strategies required to protect and sustain the Long Island population.