Laura Chamberlin

Assistant Director for North America, WHSRN Executive Office

After a long and challenging winter, spring’s arrival brings a welcome change and a renewal of life. For the Delaware Bay, the onset of warmer temperatures and long, sunny days precedes one of nature’s great spectacles: the horseshoe crab spawning season and the return of millions of these ancient creatures to beaches up and down the bay. The horseshoe crabs are coming – and when they arrive, reTURN the Favor will be ready.

Started in 2013, reTURN the Favor is a multi-partner program whose mission is to rescue horseshoe crabs that become overturned or stranded in rubble or riprap when they come ashore to lay their eggs. Working with the New Jersey Department of Environmental Protection, they bring together trained volunteers to collect data, make observations, identify potential beach hazards – and save crabs.

The program works: in the eight years since the program’s inception, volunteers have rescued close to 700,000 horseshoe crabs on nearly 4,000 walks. Those volunteers are key to the program’s success; it is no exaggeration to say that reTURN the Favor would not exist without their tireless efforts rescuing crabs, identifying hazards, and removing beach debris that can both trap horseshoe crabs and pose a danger to us. And last year was no exception. Despite the challenges and restrictions posed by COVID-19 – including a shorter walk season, reduced ability to train new volunteers, and the need to keep group sizes small and participants socially distanced – volunteers rescued more than 180,000 horseshoe crabs, the highest single-season total since the program began.

The key to reTURN the Favor’s importance lies in two factors: the unique position of horseshoe crabs in the ecosystem and the Delaware Bay itself. While the Bay contains the largest spawning population of these crabs in the world, overharvesting has driven the decline of the population by 80 percent. This decline is not just trouble for horseshoe crabs, but also for hundreds of thousands of shorebirds on their way to breeding grounds in the Arctic. The crabs’ eggs provide a critical source of food for these weary travelers as they rest and refuel. Among this imperiled group is the federally threatened Red Knot; for these birds, horseshoe crab eggs bridge the gap between extinction and survival.

Horseshoe crabs are also critical to human health: their blood contains a protein called LAL that can detect the presence of a bacterial toxin that can be fatal to humans. Pharmaceutical companies use LAL to ensure that everything from surgical implants to vaccines are free of this toxin – and will continue to do so until a synthetic alternative is approved for use and adopted. As we struggled with the pandemic over the past year, this factor came sharply to light: LAL was critical in ensuring the safety of COVID-19 vaccines.
“The reTURN the Favor effort has developed into a rewarding and impactful program for all involved by providing 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. “As we enter the ninth year of reTURN the Favor, we’re seeing the real impact that this program is having on horseshoe crabs and the Delaware Bay as a whole.”

Laura Chamberlin, Assistant Director for the Executive Office of the Western Hemisphere Shorebird Reserve Network Executive Office, added, “As more and more volunteers are stepping up to rescue horseshoe crabs, we are also seeing them speak up in other ways to protect horseshoe crabs and their habitat. In this way, volunteers are saving both the individual and the ecosystem.”

For more information about reTURN the Favor, visit the program’s website at