These sightings help biologists identify nesting beaches around the state.

hsc under water
A pair of horseshoe crabs swimming toward beach to spawn

Horseshoe crabs can be found in the United States from Maine to Florida. Adult horseshoe crabs are usually found offshore, but, like sea turtles, they come ashore to sandy beaches to mate and lay eggs.

Horseshoe crabs are declining in number throughout their range due to a variety of factors, including overharvesting for the bait industry and loss of reproductive habitat. Seawalls and other types of shoreline development can disrupt the horseshoe crab's reproductive activities.

Horseshoe crabs are important for several reasons.  Shorebirds rely on their eggs as a primary food source during their long migrations. (The decrease in horseshoe crab abundance has contributed to notable declines of many shorebird species.) They are also used as bait in the eel and whelk fisheries. Horseshoe crabs are of extreme importance in the biomedical industry--their copper-based blue blood is used to test that all inectible drugs and medical equipment are bacteria free. 
(You can read more about the horseshoe crab on Facts and FAQ). 

Because there is such a high demand for horseshoe crabs, and because their numbers are limited, many states have put restrictions on horseshoe crab harvesting.  The Atlantic States Marine Fisheries Commission (which manages horseshoe crabs on a federal level) developed a Horseshoe Crab Fishery Management Plan, which requires all Atlantic coastal states to identify horseshoe crab nesting beaches. 

In 2002, the Fish and Wildlife Research Institute (FWRI) initiated a survey in which the public can report sightings of horseshoe crabs nesting activity.  These observations will help biologists gain a better understanding of where and when horseshoe crabs are spawning in Florida.  The horseshoe crab has existed for hundreds of millions of years. With the public's help, it will ensure they will survive for many more years to come.

If you have observed horseshoe crabs spawning in Florida (two or more connected together), please report this information by filling out our Online SurveyExternal Website where you can input your numbers directly, or you can contact us by e-mail or phone. The e-mail address and telephone number are listed below. 

Toll-free phone: 1-866-252-9326


SURVEY RESULTS: Through December 2017, FWRI had received 4,051 reports since implementing the survey program in April 2002.

 HSC Spawning 2002-17

Observers in 34 coastal Florida counties have reported sightings of horseshoe crab spawning activity, which FWRI records by county. The high numbers of reports from Hillsborough and Pinellas counties reflect proximity to FWRI headquarters in St. Petersburg, where awareness of the horseshoe crab reporting system is high.

FWC Facts:
Medical researchers are investigating the use of compounds produced by harmful algae to treat some diseases in humans.

Learn More at AskFWC