Nature Coast Master Gardeners (NCMG’s), naturalists and citizens count success one crab at a time. Limulus watch is a citizen science initiative whose goal is to identify, tag and record horseshoe crab population numbers to better manage these important marine animals. “17 volunteers were trained in 2016, 79 in 2017 and 113 unique participants in 2018” reported Savannah Berry, Ph.D. University of Florida Regional Specialized Agent - Coastal Ecosystems, during the season finale at Nature Coast Biological Station, Cedar Key.

Resighting is one method of tracking crab migration, populations and health. Fall 2017 – Spring 2018 saw a 6.3% resighting rate. Several resights were credited to the general public, being reported by citizens at large. Dr. Jane Brockmann, UF Emeritus Professor and Tiffany Black, FWC Horseshoe Crab Survey Coordinator presented resighting pins, provided by U.S, Fish and Wildlife Service. “Pins are awarded by the Service when qualifying tag information is reported” stated Brockmann.

The Migrating Crab Award, for surveying the most sites in one season, was presented to Linda Redditt and Linda ‘Digger’ Headley. The Golden Awl Award was presented to Deborah Goad in recognition of the most tagged crabs. Goad also bagged the Terminal Molt Award for most volunteer hours during the season.

Goad (John) and George, provided leadership to the Seahorse Key sites. They made surveying a pleasant experience for novice participants Carol ‘Crab Whisperer’ Wood and myself. I admit being hesitant to handle crabs, especially with all the flailing legs. However, I soon found my niche and three hours of measuring and tagging passed quickly.

On full and new moons in fall and spring, horseshoe crab congregate at high tide to breed. They prefer sandy sites in bays or inlets, protected from waves. Crab watch participants count and record horseshoe crab numbers at specific sites. Mating pair as well as single “satellite” males are included in the count. At the same time, surveyors scout for previously tagged “resight” crabs.

Crabs are collected, weighed and data recorded. Measurement is taken at the shell’s widest point. Shell damage, missing limbs, tail injury and approximate age are documented. Identification tag number are assigned. A small hole is made through the shell and the barbed tag installed. Typically, identification tags are placed on the left side of the shell. That’s the crabs left, when tail is pointed toward you. Tagged crab are released at shoreline.

Florida’s horseshoe crab serve an important ecological function. Its eggs are a food source for migratory birds and shore birds. Sea turtles, fish and true crabs feed on eggs and horseshoe larva.

Along the northeast United States, horseshoe crab are harvested for used in human medicine. Wild caught horseshoe crab are delivered to laboratories where the heart is punctured and some blood extracted. Most horseshoe crab survive the procedure and are released alive.

Horseshoe crab have blue, copper-based blood that contains a special clotting agent, Limulus Amebocyte Lysate (LAL). LAL clots when exposed to endotoxins, chemical poisons released by certain infectious bacteria. The LAL test is extremely sensitive. As a result, it is the standard for testing all injectables since 1987.  The U.S. Food and Drug Administration, requires an LAL test on all human and animal injectable and intravenous drugs, on medical devices used to deliver these injectable drugs, and on all prosthetic devices (such as hip replacements or heart valves).

Horseshoe crab don’t bite or sting, however they do have sharp spines along the lower rim of the shell. Therefore, handle from the front upper portion of the shell. Gently lift crab from the sand by placing your hands around the front edges of the shell with the tail facing away from you. Never pick up a crab by its tail. This may permanently damage the joint at its base or break the tail. The tail helps to steer and right the crab if turned upside down. Report the tag number and state location to the Florida Fish and Wildlife Commission. The toll-free number, 1-866-252-9326, is on the tag. Or e-mail This email address is being protected from spambots. You need JavaScript enabled to view it.. 

Black congratulated participants for launching these original Florida sites. Seven areas on Cedar Key Island (Levy County), New Smyrna Beach (Volusia) and Fort Desoto (Pinellas). In 2017, two sites at Bald Point State Park (Franklin County), Shired Island (Dixie County) and Hagans Cove (Taylor County) were added. Spring of 2018 brought in an additional three beaches at Fort Clinch State Park (Nassau County). Plans are to expand to forty coastal sites in 2019. Contact Tiffany Black, 352-543-1080 or email This email address is being protected from spambots. You need JavaScript enabled to view it. to participate or for more information.

All extension and services are open to all without regard to race, color, age, sex, religion, national origin or handicap.

*****