Maryland beaches are now witnessing the remarkable return of the annual spawning migration of horseshoe crabs (Limulus polyphemus), a natural phenomenon that has captivated scientists and nature enthusiasts for centuries. Taking place from May through July, this ancient wildlife migration reaches its peak during high tides surrounding the full and new moons in June. Dating back approximately 350 million years, this migration along the Atlantic coast is considered the world’s oldest and largest wildlife migration.
The Maryland Department of Natural Resources, comprising biologists dedicated to ecological and scientific research, is actively monitoring the horseshoe crab population as part of its ongoing efforts. They encourage the public to participate in the Horseshoe Crab Volunteer Angler Survey to gather valuable information about spawning activity and horseshoe crab sightings. This survey is conducted in collaboration with the Maryland Coastal Bays Program, a partnership that aims to protect and restore the coastal bays and their surrounding watershed.
During the spawning season, a single female horseshoe crab can deposit around 20,000 eggs into the sand, serving not only to perpetuate the ancient species but also as a crucial food source for migratory shorebirds preparing to return to their summer nesting grounds in northern Canada. Additionally, horseshoe crab larvae play a vital role in the diets of juvenile Atlantic loggerhead turtles, as well as species like striped bass, American eel, and flounder.
Besides their ecological importance, horseshoe crabs also offer a valuable resource to humans. Their blood, which contains copper-based cells, is critical for biomedical research. Specially permitted fishing operations collect the crabs, draw blood in biomedical facilities, and then release the animals back into the water. This process helps supply the biomedical industry with a vital component for research and development.
Despite their fearsome appearance with their armored exoskeletons and tails, horseshoe crabs are docile creatures that pose no threat to humans. In fact, their tails serve various purposes, including maneuvering through sand and water, acting as a rudder, and helping the crab regain its balance when accidentally overturned. It is important to note that horseshoe crabs can survive outside of water for only a short period.
To aid horseshoe crabs, humans can play a crucial role in ensuring their well-being. Individuals who come across horseshoe crabs trapped in rock jetties or struggling to the right can assist by gently flipping or moving the animal using both hands. It is essential to avoid picking up the horseshoe crab by its tail, as this may cause injury.
The annual horseshoe crab spawning migration provides a unique opportunity for both nature lovers and scientists to witness and study one of the world’s most ancient wildlife phenomena. By actively participating in the Horseshoe Crab Volunteer Angler Survey, individuals can contribute to understanding and conservating these remarkable creatures. The return of the horseshoe crabs to Maryland beaches serves as a reminder of the resilience and beauty of nature and the importance of safeguarding our coastal ecosystems for future generations.