The horseshoe crabs along the Delaware coast have made a major rebound after declines in the 1990's. In our partnership with Spotlight Delaware Delmarva Public Media's Don Rush talks with reporter Olivia Marble who went out this month to follow the volunteers who count the little creatures.
The annual migration of horseshoe crabs to Delaware beaches is showing encouraging signs of recovery after decades of decline, according to researchers and volunteers who monitor the species each spring.
Horseshoe crabs have remained largely unchanged for roughly 450 million years. Each year during high tide, teams of volunteers survey Delaware beaches to estimate the size of the spawning population.
Spotlight Delaware reporter Olivia Marble recently joined one of those nighttime surveys, where volunteers use a sampling method to count crabs within randomly placed square plots on the beach.
“They look ancient, and that's because they really are,” Marble said. “Some people call them living fossils because they really have not changed in appearance.”
Scientists believe horseshoe crab populations fell sharply during the 1990s due to overharvesting. The animals have long been collected for fishing bait and fertilizer, while biomedical companies have relied on their unique blue blood to test medical products for contamination.
“Harvesting just got to a point where it was difficult for the horseshoe crabs to replenish in population,” Marble said.
Conservation measures limiting annual harvests have helped reverse that trend. Marble noted that population estimates have rebounded to nearly the levels recorded in 1990.
The recovery has implications beyond the species itself. Horseshoe crab eggs are a critical food source for migratory shorebirds that stop along the Eastern shore during seasonal migrations.
“A lot of birds ... stop by Delaware and they eat their fill of these very nutrient-dense eggs,” Marble said. “That gives them the energy to keep flying.”
The full interview can be heard on this Friday's Delmarva Today at noon on WSDL and WESM.
