horseshoe crabs

Teams Mobilize for Coastal Invasion of Horseshoe Crabs

By Guest Author Posted on August 26, 2022

Guest post by Burt Golub

They came at night as the moon pulled on the earth in its perigee.  Quiet and unobtrusive the sensors under their hard protective outer covering probed the surroundings for food, while the UV sensors on top reacted to wave lengths humans could not see.  

Other sensors saw what humans could.  

Noiselessly and often undetected they left behind millions of eggs to continue their species on our planet as they had for the last 450 million years.

Aliens? UFOs?  

No. These are the harmless horseshoe crabs (Limulus polyphemus) doing their thing during the spring and fall spawning seasons laying eggs along the shorelines at high tide.  Amazingly they haven’t changed in the 450 million years they’ve existed, long before the dinosaurs (200 million years ago).  And even more amazingly – the health of today’s human population is dependent on them.

The Horseshoe Crab Watch

Over the next two months, you may see a small blue pickup truck and a team of volunteers with clipboards and “FWC Volunteer” T-shirts walking along Green Key Road in Pasco County.  These are a group of dedicated volunteers helping count, tag and record previously tagged Horseshoe Crabs during the annual nationwide Horseshoe Crab Watch program. Here in Florida, we call it, “Linked with Limulus”. 

Although the nationwide Horseshoe Crab Watch program has been an active program in the northeast U.S. since 1998 (DE, CT, NY), here on the Gulf Coast it has only been since 2016 these population counts have been conducted, and only in the last two years in Pasco County.

citizen scientists
Burt Golub and other volunteer Citizen Scientists tag and record the number of horseshoe crabs found along the Gulf Coast to help Florida Fish & Wildlife keep track of these valuable prehistoric sea creatures. Image by Burt Golub

Horseshoe crabs (Limulus polyphemus) are totally harmless and not a food source except for marine turtles and sharks. These prehistoric crustacean’s have been harvested in the thousands in Delaware and elsewhere to be ground up for fertilizer or used as bait for the eel and whelk industry. 

Only recently was their real value discovered in the biomedical field.  Every vaccine and medical implant today is tested for contaminants with an extract from the horseshoe crab’s uniquely blue colored blood before being made available to the public.  The extract is called Limulus Amebocyte Lysate (LAL) and is produced by just a few laboratories by extracting 30% of the HSC’s blood for processing and then releasing the animal back into the wild.

Participating in Citizen Scientist Programs for the Florida Horseshoe Crab Watch

Citizen Scientist Programs are an important part of the Fish and Wildlife Commission’s scientific endeavors. Manpower shortages in many government and academic agencies, especially where field work is concerned, has given the public more opportunities to contribute to important scientific projects such as this one. 

The Florida Horseshoe Crab Watch program was created to learn where and at what densities horseshoe crabs spawn, and whether populations were changing through time.

With accurate data collected over a long period of time by volunteers such as these the sponsoring organizations (FWCRI, U/F Sea Grant & IFAS & Dept. Biology) can determine population numbers, reproduction rates, range of movements, and impact on the environment by human populations and development in our state.

If you want to get involved, next time you see a horseshoe crab look for a round white disc on the side of their shell, then photograph or record the number on the disc and send that number (do not remove the tag) to Florida Fish and Wildlife at ( or call 1-888-546-8587 (1-888-LIMULUS).

tagging a horseshoe crab
Tagging horseshoe crabs is a simple process and assists Florida Fish & Wildlife in meeting their management goals. Image by Burt Golub.

How to Interact with a Horseshoe Crab Safely 

Under no circumstances should you pick up the horseshoe crab by its tail. The tail is the horseshoe crab’s only means to right itself if turned upside down by wave action. 

Pick them up with two hands by the sides of the front larger shell. They can’t hurt you unless you accidentally get a finger caught in the hinge between the front and back shells. The tail is harmless, and the animals are non-aggressive.   

If you want to join the FWC team look on-line for Florida Horseshoe Crab Watch.

Contact the Pasco County Coordinator Burt Golub or the Hernando County Coordinator, Brittany Hall-Scharf for more information. 



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