Horse Shoe Crabs Mating UNH

Horseshoe Crab Survey in Great Bay

Coastal Research Volunteers

  • May 1–July 1

This is an ongoing Citizen Science Experience. Contact the sponsoring organization to join in.



High Adventure





Volunteers are needed to help survey the shores of Great Bay for the presence of horseshoe crabs during their spawning season (April-June).  During this season, thousands of horseshoe crabs travel to the intertidal zone at high tide to spawn. Locally, this phenomenon occurs in the Great Bay Estuary. As a citizen science project and an effort to gather an accurate estimate of the horseshoe crab population in our estuarine ecosystem, we are reinstating the horseshoe crab spawning and tagging surveys after a several year lapse.

Surveys will take place every day at high tide at five different locations throughout the Great Bay Estuary. Volunteers walk along the selected spawning beaches and count the number of males and females present at these locations. All skill levels welcome.  It's an awe-inspiring experience - come try it!

This project is coordinated by researchers and students at the University of New Hampshire, including the Coastal Research Volunteers. Training sessions will take place in spring, and will be posted on Nature Groupie.

Great Bay Horseshoe Crab Survey

Questions? Contact Coastal Research Volunteers coordinator Wells Costello: or 603-862-6707