Monitoring Horseshoe Crab Breeding with NYC Audubon


On Sunday, May 27, the MSNH joined NYC Audubon again in their annual survey of horseshoe crab breeding in Jamaica Bay. The weather was perfect on this full moon night and as the sky darkened we saw many male horseshoe crabs come in with the tide searching the shallow waters for females. We witnessed several males trying to latch onto a single female hoping to externally fertilize her eggs. We also tagged 75 horseshoe crabs so that researchers can track their movements and assess the stability of the population. NYC Audubon's annual horseshoe crab survey is crucial for monitoring the population of these magnificent ancient arthropods, which are in decline due to overharvesting for medical and fishing purposes. A special thank you to Dottie, NYC Audubon and Dennis and to all participants for such a wonderful event!


Horseshoe crabs, despite their name and superficial resemblance, are not crabs. They actually belong to their own class Xiphosura in Chelicerata, an arthropod group that also includes the classes Arachnida (spiders, scorpions, ticks, etc), Eurypterida (the extinct sea scorpions and also MSNH's logo taxon), and Pycnogonida (sea spiders). Worldwide only four extant species of horseshoe crabs exist and all species except the Atlantic horseshoe crab, Limulus polyphemus, are found in the Indo-Pacific Ocean. Extinct horseshoe crab species have also been described and the oldest fossil, found in Canada, dates to the Upper Ordovician, 445 million years ago! Despite their remarkable old age, horseshoe crabs have changed little morphologically since their first appearance and are therefore often referred to as 'living fossils' in the scientific literature. To learn more about horseshoe crabs, check out this article on them from our Taxon of the Month page.

To view more photos from this event, check out here. All photo credit goes to Glenn Doherty.

Useful Information/Links

NY Horseshoe Crab Monitoring Network

To learn more about horseshoe crab breeding, check out research by Dr. H. Jane Brockmann at the University of Florida.