Horseshoe Crab Monitoring in Barnegat Bay, NJ
Save Coastal Wildlife will be conducting surveys of spawning horseshoe crabs around Barnegat Bay starting in spring 2025. This project is in collaboration Montclair University, as well as the Fiends of Island Beach State Park and New Jersey State Park staff.
At Island Beach State Park, Save Coastal Wildlife will work to train community science volunteers with the Friends of Island Beach State Park in the spring to count adult horseshoe crabs spawning on and around the new and full moons at high tide.
The data collected during these surveys will be submitted to the State of New Jersey, Fish and Wildlife Division. The information will help to fill a gap in horseshoe crab knowledge in New Jersey, as extensive monitoring activities exist in Delaware Bay, New York Harbor, including Sandy Hook Bay and Raritan Bay, and Shark River, but not in Barnegat Bay.
Volunteer monitoring activities will take place at Island Beach State Park along the extensive shoreline of Barnegat Bay. Save Coastal Wildlife and volunteers with Friends of Island Beach State Park will be seeking suitable nesting areas for horseshoe crabs. If found, these areas will be monitored yearly for their productivity.
If you are interested in being a volunteer for this project, please contact Friends of Island Beach State Park.
Aerial Drone image looking south towards the Barnegat Inlet at New Jersey Island Beach State Park between the Atlantic Ocean and Barnegat Bay.
Barnegat Bay Is a Challenging Place for Horseshoe Crabs to Nest.
Barnegat Bay is a unique estuary in New Jersey, characterized by its shallow depth, narrow width, and limited number of outlets, primarily through the Barnegat Inlet. It's a 43-mile-long lagoon estuary protected by a system of barrier beaches, wetlands, and dunes. The bay's shallow nature and limited flushing, coupled with its proximity to developed areas, make it susceptible to nutrient loading.
The limited number of outlets, primarily at the approximately 300-foot wide Barnegat Inlet, means this busy entrance is used for horseshoe crabs to enter the estuary from their overwinter habitat in the ocean.
Once in the Barnegat Bay estuary, horseshoe crabs often find a lack of available nesting beaches. Although the southern end of Barnegat Bay is rich in coastal wetlands, particularly salt marshes, this is not ideal nesting habitat. Horseshoe crabs typically need wide, sandy beaches to nest and lay their eggs. They prefer sandy beaches in bays and coves that are protected from strong wave action, where the sand is porous and well-oxygenated. This allows the eggs to develop properly in the sand.
Farther north in Barnegat Bay, the coastline is highly developed with bulkheads and other forms of human development. Bulkheads and other hardened structures on the shoreline can reduce the availability of the estuarine beach habitat that horseshoe crabs need for spawning. They can block access to spawning beaches, eliminate sandy beach habitat, or even trap and strand spawning crabs.
Barnegat Bay has extensive coastal wetlands, including salt marshes, which are characteristic of the region. Yet, this is not ideal habitat to support a robust population of horseshoe crabs. Female horseshoe crabs require wide sandy beaches to allow the crabs to crawl up onto the shore to lay their eggs, which they do during high tide. They also prefer coarse sand over fine sand because it allows for better air circulation around the developing eggs, preventing suffocation.
