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UF, FWC: Citizen science key to tracking horseshoe crabs

GAINESVILLE, Fla. — As the weather warms, tourists won’t be the only ones heading to Florida’s beaches. Horseshoe crabs also come ashore this time of year, though they are more interested in finding a mate than getting a tan.

For Jane Brockmann, professor emeritus of biology at the University of Florida, the horseshoe crabs’ arrival is a chance to track and monitor these primeval-looking creatures. Brockmann and a few dozen volunteer citizen scientists will spend the next few weeks surveying horseshoe crabs in Florida’s Big Bend.

“We are conducting both population surveys and tagging,” Brockmann said. “This will help us estimate population numbers and determine the status of populations at a number of different sites. The tagging helps us see how much the animals are moving around.”

Brockmann and her students have spent decades studying horseshoe crabs at Seahorse Key Marine Laboratory. Recently they have been collaborating with the Florida Fish and Wildlife Conservation Commission, which is responsible for managing horseshoe crabs in Florida.

Two years ago, this effort expanded to include UF Institute of Food and Agricultural Sciences, which oversees the project’s volunteer component.

Savanna Barry, Florida Sea Grant agent with the UF/IFAS Nature Coast Biological Station, trains volunteer citizen scientists before they go into the field.

“We have active sampling in Levy, Dixie and Taylor counties, and we’re hoping to include Nassau and Duval counties this fall,” Barry said. “Using citizen scientists lets us collect data over a larger area than we could cover with a typical research team.”

If you see a horseshoe crab flipped on its back, carefully pick it up by its shell—not its tail–and turn it over, Barry said. You’ll be doing more than a good deed.

“Horseshoe crab eggs are an important food for many shore birds, including the red knot, which may soon be listed as endangered,” Barry explained. “The eel and conch industries likewise rely on horseshoe crabs for bait.”

And if you’ve ever gotten medical treatment, you have horseshoe crabs to thank, Barry said. “Their blood has a special property that makes it coagulate around bacteria, so it’s used to test medical devices and vaccines for contamination,” Barry said.

At the moment, it’s not clear how many horseshoe crabs are in Florida’s waters. The lack of data means the FWC can’t determine whether the species needs to be protected by the state, said Tiffany Black, a researcher with the FWC who represents Florida on the Horseshoe Crab Technical Committee of the Atlantic States Marine Fisheries Commission.

“To date, we’ve only been able to do a presence-absence study based on what people have reported online. But with citizen scientists, we can gather standardized data,” Black said.

Citizen science projects also let residents get involved with research happening in their communities.

“I grew up in Virginia and saw these crabs all my life. I was so excited to be part of the new research going on in the Gulf,” said Katie Granger, who has been volunteering with the horseshoe crab survey since its start. “The best part of helping with the surveys is being trained to care for these creatures and that I can go in the water, examine and tag them.”

Debbie Goad also grew up around horseshoe crabs and jumped at the chance to learn more about them. “I’ve enjoyed volunteering because I’m treated as an equal, even though my knowledge is limited, and I don’t have a science background,” she said.

Organizers hope that the survey will eventually cover all of Florida.

“Partnering with UF gives us reach throughout the state,” Black said. “We have 1,200 miles of shoreline, so we need to harness the power of researchers, UF/IFAS Extension agents and the public.”

If you see a tagged horseshoe crab, please note the number on the tag and use the hotline (1-888-LIMULUS) or to report the number, sighting location and condition of the crab.


By: Samantha Grenrock, 352-294-3307,

The mission of the University of Florida Institute of Food and Agricultural Sciences is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS works to bring science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents. Visit the UF/IFAS web site at and follow us on social media at @UF_IFAS.