Marine Discovery Center Still Active in Horseshoe Crab Monitoring

By Tess Sailor-Tynes

Marine Discovery Center

Conservation Science Coordinator

Marine Discovery Center has a long history with Limulus polyphemus, also known as the Atlantic Horseshoe Crab.

This species exists along the East coast of the United States and on both coasts of Florida. They have scientific and medical significance and are facing threats from issues like habitat loss, predation from invasive species and pollution.

In 2018, MDC’s Conservation department officially joined Florida Horseshoe Crab Watch (Linked with Limulus) – a statewide community-science effort organized by the Florida Fish and Wildlife Conservation Commission (FWC).

Since joining, MDC has focused on gathering data for the Northern region of the Indian River Lagoon. Historically, site locations included Riverside Drive, Firecracker Island and two shorelines within Canaveral National Seashore. Throughout this timeline, staff and volunteers have ventured out on high tides during full- and new-moon cycles to monitor for nesting behavior.

In addition to biological data, environmental data is taken to create a better understanding of ideal or suboptimal conditions for the horseshoe crabs. Water and air temperature, salinity and wind direction have been significant indicators for nesting cues and help provide guidance for when surveys should take place.

Visual surveys illustrate data for the general population, and tagging surveys provide health data for individuals using parameters such as weight, size, age, and any observable injuries. If tagged horseshoe crabs are resighted, FWC can analyze populations for lifespan and range.

Marine Discovery Center staff has observed changes in survey sites over the years and now focuses on Canaveral National Seashore walking surveys and kayak surveys to Firecracker Island. Data collected in 2022 also suggested that the back-to-back hurricanes had a major impact on nesting numbers at sites.

After convening with other regional scientists and coordinators from the Florida Horseshoe Crab Watch, MDC implemented game-camera monitoring into its program for the 2025 season. This data, aligned with environmental data, can further assist in understanding where and how horseshoe crabs utilize local habitats for nesting and how to best manage those areas for increased biodiversity and ecosystem health.

If you ever observe a tagged crab while on the lagoon, please report it (and a photo of the tag number) to 1-888-LIMULUS (546-8587).