It's Living Fossil Season —Volunteer to help tag them

Every spring, something ancient and extraordinary unfolds along the sandy shores of the Delaware Bayshore. Thousands of horseshoe crabs — creatures that have roamed Earth's oceans for hundreds of millions of years — crawl ashore to spawn. And for over a decade, the American Littoral Society has been there to meet them, with tags in hand. 

For just as long, we've been joined there by countless volunteers who help put those tags on horseshoe crabs so we can better gauge the effectiveness of our work restoring habitat along the bay. ​

Registration recently opened for any who would like to lend a hand with our horseshoe crab tagging program — and this year, we're heading to new beaches. Whether you're a seasoned tagger or putting on a headlamp for the first time, you're invited to take part in this important effort. 

Register for Delaware Bay Horseshoe Crab Tagging

Delaware Bay is home to the largest population of spawning horseshoe crabs in the world — and that matters far beyond the crabs themselves. The bay serves as an important stopover for migratory shorebirds, including the federally threatened Red Knot, making their way along the Atlantic Flyway to Arctic nesting grounds. Each spring, hundreds of thousands of birds descend on bay beaches, to gorge on horseshoe crab eggs and fuel the final leg of their journey. 
 
Timing is everything for this intersection of hungry avians and lumbering arthropods. If the crabs don't show up to spawn, the birds don't have enough to eat. So, understanding where crabs go, how they move, and which beaches they prefer isn't just academic. It's essential. 
 
Those beaches are what brought the American Littoral Society to New Jersey's forgotten coast. In 2012, Hurricane Sandy blew into Delaware Bay with devastating effect, stripping shorelines of sand and covering them in rubble. Female horseshoe crabs come ashore during May and June to dig shallow holes in which they lay their eggs. If there is no sand or access is blocked, egg survival is drastically reduced, which means less food for migratory shorebirds and other wildlife, as well as fewer young to help maintain horseshoe crab populations. 

---

That habitat disaster came just as horseshoe crabs were beginning to recover from a crash in the 1990s that was brought on in large part by over-harvesting. At that time, horseshoe crabs were used as bait for companies fishing for eel and whelk, as well as fertilizer and livestock feed. 
 
As a result, population numbers declined an estimated 90 percent, before New Jersey banned taking horseshoe crabs for most purposes. That Littoral Society led lobbying efforts for the moratorium and continues to fight against bait harvesting in neighboring states. However, pharmaceutical companies are still permitted to bleed crabs for their copper-based blood, which is used for medical testing.  
 
Working with Conserve Wildlife Foundation of New Jersey and a wide range of partners, including federal and state agencies, county and local municipalities, business groups, and private foundations — the Society responded to the loss of habitat by starting a program to restore those Delaware Bay beaches crucial for horseshoe crabs.  

---

The tagging program came soon after as a way to measure whether restoration efforts were actually working: Were crabs returning? Were restored beaches being used to spawn?   
 
The answer, it turns out, is yes. Data collected from surveys shows that both horseshoe crabs and Red Knots prefer restored beaches over unrestored ones.  

Each tag attached to a crab becomes a data point in a growing picture of how this species moves through the bay. When tagged crabs are resighted — either on the same beach or a different one — researchers learn about seasonal patterns, year-over-year movement, and population distribution. One intriguing finding so far: while crabs tend to appear near the same beach during spawning season, the broader distribution of local populations across the bay shifts from year to year. 
 
Monitoring of the restored Delaware Bay beaches also includes counts of crab egg density and, through partners, Red Knot numbers, which offer insight into beach usage and ideal spawning conditions. That kind of nuance matters for management decisions — including identifying which beaches might be candidates for future restoration. 
 
To date, the Littoral Society's horseshoe crab tagging program — helped annually by hundreds of volunteers — has tagged nearly 40,000 crabs across beaches including Thompsons, Moores, Fortescue, Dyers Cove, Reeds, Cooks, Kimbles, and Pierces Point. This year, the effort is expanding to Bay Point and Green Creek. 
 
The Society has also operated smaller programs along the Shark River in Monmouth County, New Jersey, as well as Slaughter Beach, Delaware. 
 
Find more information on our website about our crab tagging program and how you can participate. Space is limited for each tagging session to ensure a quality experience for both volunteers and wildlife, so sign up soon! ​

---