By ALISON MITCHELL
Executive director, New Jersey Conservation Foundation
Once there was a superabundance of horseshoe crabs, and armadas of females blanketed the beaches of the Delaware Bayshore.
Through the 1990s, New Jersey’s horseshoe-crab breeding and coinciding red knot shorebird migration was a spectacular natural phenomenon. “On the sand, there were around 50,000 horseshoe crab eggs per square meter,” says Larry Niles, biologist and co-creator of the Horseshoe Crab Recovery Coalition.
Today, horseshoe crab egg densities are down to 10,000 per square meter, a 90% decline over just three decades. The phenomenon has become a whisper.
In the early 2000s, the Atlantic States Marine Fisheries Commission and the state’s Marine Fish Agency allowed an over-harvest of horseshoe crabs for use as bait. In the years that followed, regulatory agencies allowed anywhere from one to two million crabs to be harvested per season.
Conservationists across the Eastern seaboard gathered in protest. But the agencies responded by implementing regulations that had no real impact. Despite an eventual New Jersey ban on harvesting crabs for bait, “the populations have never recovered,” says Niles.
The unfathomable losses led him and others to help protect the ancient creatures that hold the key to reversing the dramatic decline in shorebird populations. He pulled together the state’s leading scientists, and in 2018, the Horseshoe Crab Recovery Coalition was formed.
The importance of horseshoe crabs cannot be overstated. They have remained largely unchanged over the past 450 million years and they hold together a complex web of relationships in the ecosystem, a critical link in coastal biodiversity.
Every spring, horseshoe crabs lay millions of eggs. When females are abundant, they lay more than can fit deep in the sand, resulting in floating eggs that will never hatch but instead feed shorebirds, fish, turtles and other wildlife. Without the excess eggs, New Jersey’s migratory shorebird population is in peril.
The relationship between the crabs and red knots goes back 60 million years; the birds rely heavily on crab eggs as migratory fuel. Red knots are federally protected under the Migratory Bird Treaty Act and are listed as endangered or near threatened, depending on the state. Threats to red knots include direct effects from climate change; reduced food availability at stopover points; and disturbances by vehicles, dogs, drones, planes and boats. A staggering 94% have disappeared.
In the 1960s, scientists discovered that horseshoe crabs’ blue blood clotted in the presence of bacterial toxins. Since vaccines, drugs and medical devices have to be sterile, a better toxin-detection system means less contamination risk for patients. Fishermen soon started collecting and selling the prehistoric animals for medical purposes.
According to Niles, the bleeding industry is completely unregulated and the number of crabs being impacted is startling. Throughout the region, some 1.1 million horseshoe crabs were caught for the biomedical industry in 2023.
For decades, horseshoe crabs have been taken from their natural habitats, loaded into trucks and delivered to bleeding facilities. Up to 50% of their blood is drained and there is no enforcement around how the crabs are handled or regulations about when or how they are released.
But the Horseshoe Crab Recovery Coalition is pushing pharmaceutical companies in a new direction. A synthetic version of the blood was created, and for two years, the coalition has worked to shift the industry toward the synthetic alternative.
Unfortunately, companies are not required to switch to the safer – and more cost-effective – synthetic. The coalition isn’t just focused on keeping a few token horseshoe crabs and red knots from going extinct; it wants to help nature rebuild the once-incredible Delaware Bay phenomenon.
To join and support the Horseshoe Crab Recovery Coalition, please visit hscrabrecovery.org/.
