Using citizen science to track population trends in the american horseshoe crab (limulus polyphemus) in florida

We used citizen science to improve understanding of population trends and behavior in the American horseshoe crab (Limulus polyphemus) along the entire coast of Florida. First, we used 18 years of public sightings data, beginning in 2002, on horseshoe crab mating to determine which spawning locations were used most. Then, a subset of those locations was more rigorously surveyed through the Florida Horseshoe Crab Watch program. Florida Horseshoe Crab Watch, implemented in 2015 by a collaboration between the Florida Fish and Wildlife Conservation Commission (FWC), University of Florida Institute of Food and Agricultural Science (UF/IFAS), University of Florida Department of Biology (UF), and Florida Sea Grant (FSG), uses trained citizen volunteers to survey beaches with high spawning activity. Volunteers count, weigh, measure, and tag horseshoe crabs that are nesting on the shoreline. These data contribute to a nationwide mark-recapture program managed by the United States Fish and Wildlife Service (USFWS) and are used in Florida to inform species management decisions and to increase general understanding of the species. We developed and adapted both phases of the research by implementing modern technology, improving survey design, and expanding geographic coverage. The quality and accuracy of public reports have improved with technological advancements. The quality of the morphological data collected by Florida Horseshoe Crab Watch volunteers was comparable to that of data collected by professional scientists. Our design can serve as a model for programs regardless of region or taxon of interest and when funding is limited but public interest is high.