The Horseshoe Crab Survey is an initiative utilizing volunteer community scientists to report horseshoe crab sightings through a digital app. Salem Sound Coastwatch (SSCW) and our volunteers have been collecting data on the population of North Shore horseshoe crabs for the past two years, which has allowed us to gain new insights into the trends and behaviors unique to our local population of horseshoe crabs.
Between the survey’s introduction in May 2023 and April 2025, there have been 129 reported horseshoe crab sightings ranging from Nahant, MA to New Hampshire’s Great Bay National Wildlife Refuge, with the greatest number of reports in Salem, MA (70) and Ipswich, MA (27). Molts accounted for 50% of the total number of reported horseshoe crabs, while live horseshoe crabs made up 35% of sightings and were observed almost exclusively during the month of May. More than half of the reported live horseshoe crabs were actively mating (about 55%). This is exciting news as it provides evidence that beaches on the North Shore support breeding habitat for this species. Most mating pairs (14/25, 56%) were observed in Salem, specifically the Collins Cove Beach and Forest River (Pickman Park and Lead Mills Conservation Area), which suggests that these locations may be local spawning “hotspots.” Interestingly, observed mating did not coincide with specific phases of the moon, which is contrary to the population of horseshoe crabs around Cape Cod.
Read more about the survey’s findings and how we’re using this information to protect Salem Sound’s horseshoe crabs by reading our Horseshoe Crab Report.
Want to be a horseshoe crab community scientist? Watch the recorded training video and report any horseshoe crab sightings through our survey, below!