The concentration of spring shorebirds on the Delaware Bay shore was a world famous natural phenomenon a few decades ago. A hundred thousand federally threatened red knots and tens of thousands of other species would crowd the beaches each spring, gorging on horseshoe crab eggs so they could complete their incredible 9,000 mile migration from the bottom tip of the Americas to the top.
A familiar sight at the shore, the horseshoe crab is not a crab at all but a harmless aquatic arachnid unchanged in 450 million years. Its bulging gray-green shell a foot or two across is roughly the shape of a horse’s foot, and its copper-based blood is blue.
But then people killed most of the horseshoe crabs, grabbing them when they came ashore to spawn and mainly chopping them up for snail bait. New Jersey put an end to that in 2008, and these living fossils from the dinosaur age slowly started coming back.
Lately they’ve gotten crucial help from people aware of their plight and making volunteer efforts to ensure the horseshoe crabs and birds have a future at the Jersey Shore.
Recently members of the state branch of the American Littoral Society and the Conserve Wildlife Foundation of New Jersey, along with the N.J. Division of Fish and Wildlife, put up signs and roped off Delaware Bay beaches to block access during the spawning season from May 7 to June 7.
Quinn Whitesall, habitat restoration coordinator for the society, said female horseshoe crabs will come onto the beach 20 times during spawning season and lay from 4,000 to 5,000 tiny green eggs in the sand.
Another effort has put volunteers to work rescuing horseshow crabs one by one, and taking steps to reduce the hazards they face during their vulnerable spawning.
Called reTURN the Favor, for the simple act of turning over a wave-flipped and perhaps doomed horseshoe crab, the program deploys volunteers to the beaches to also rescue them when stranded in rubble or riprap, to identify beach hazards, and to observe and gather data.
In its eight years, reTURN the Favor-trained volunteers have rescued nearly 700,000 horseshoe crabs during 4,000 beach walks. Last year alone, despite the pandemic, they rescued more than 180,000.
Horseshoe crabs the past year have had an essential role in overcoming the COVID-19 pandemic. Their blood contains a protein for detecting the presence of a bacterial toxin that can be fatal to people, so pharmaceutical companies use it to test vaccines and surgical implants. The past year, the blood was critical in ensuring the safety of COVID vaccines.
This, too, is a burden on the horseshoe crab population. Although the creatures are released after the extraction of some of their blood, a significant number of them don’t survive the process. Researchers are trying to develop a synthetic alternative to the blue blood, but so far none has been approved for use and adopted.
The steering committee for reTURN the Favor is comprised of the Wetlands Institute in Stone Harbor and the Western Hemisphere Shorebird Reserve Network in Manomet, Massachusetts. Program partners include NJ Audubon, the Nature Conservancy, Citizens United to Protect the Maurice River, Friends of the Cape May National Wildlife Refuge, the Conserve Wildlife Foundation of New Jersey and the state Division of Fish and Wildlife.
The program provides “a simple way for volunteers and conservation organizations to join together and carefully rescue horseshoe crabs from our beaches without causing harm to other resources,” said Lisa Ferguson, director of research and conservation at the Wetlands Institute. “We’re seeing the real impact that this program is having on horseshoe crabs and the Delaware Bay as a whole.”
Volunteer support has been strong, and rescue walks have been booked full online. For more information about the program and how to help, visit returnthefavornj.org.
The bay’s horseshoe crabs are the largest spawning population of the species in the world. We’re glad so many are helping them — just in case the bay turns out to be their last stand after scuttling along beaches with dinosaurs hundreds of millions of years ago.