In Search of the Ancient Horseshoe Crab

Horseshoe crabs were once more abundant in the Pensacola Bay area than they are now. These bottom dwelling arthropods could be found plowing through the sand and seagrass feeding on smaller invertebrates. During the spring high tides of the fall and spring they would emerge along the shoreline to deposit their eggs. They could be found all around the Pensacola Beach area. And then, like other species such as seagrass, scallops, and sea urchins, they began to decline.

This scenario is no different in other parts of Florida. In many locations in the Chesapeake Bay area declines have been noted as well.

In response, the Florida Fish and Wildlife Conservation Commission (FWC) and Florida Sea Grant have partnered on a program called the Florida Horseshoe Crab Watch. In this program Sea Grant trains volunteers on how to survey and tag nesting horseshoe crabs. This program provides information to FWC so they can help manage this species.

In 2025 Florida Sea Grant trained 100 residents from Escambia and Santa Rosa County to survey for nesting horseshoe crabs in the Pensacola Bay area. Of those 21 (21%) participated in at least one survey. The objective of this project is to survey beaches that horseshoe crabs have been seen and verify nesting activity. Horseshoe crabs will nest along the shore during the spring high tides of both the spring and the fall. Our volunteers attempt to survey those beaches during those times.

The larger female horseshoe crabs will approach the beach to dig a depression and deposit her eggs. Often the smaller male will use a modified claw to hold to the female and ride her back to shore. Additional small males, known as satellites, will follow the pair and attempt to fertilize the eggs as well. Horseshoe crabs usually nest in large numbers near the same location and at the same time.

Whether nesting is observed or not, our volunteers will record the number of horseshoe crabs seen in the area. Like all arthropods, horseshoe crabs will molt their external shell to grow a new one as they grow. The number of molts found is also recorded.

In Pensacola the project focuses on finding these nesting beaches. Our trained volunteers will begin surveying in March but we ask everyone to help report horseshoe crabs when spotted.

If you see them, please contact Florida Sea Grant Agent Rick O’Connor at roc1@ufl.edu or 850-475-5230.

Horseshoe Crab photos: Bob Pitts and Barrett Johnson