Horseshoe Crab Tagging in the Delaware Bay: Farewell (For Now) to our Favorite Friends

by Kerstin Axe, ​Restoration Technician

A family visiting from California deploys a tag onto a horseshoe crab found on Thompsons Beach.

The American Littoral Society began its 14th season of horseshoe crab tagging along the Delaware Bay on April 30th, 2026. Our first night of tagging for the 2026 season was met with an early – Spring chill, as well as one of our youngest volunteers this season. Night #1 was also met with somewhat surprising low numbers of horseshoe crabs coming up onto the beach for spawning. We believe this may have had something to do with the early – Spring chill that lingered for quite some time. Despite these challenges, the season commenced with 175 tags deployed on Thompsons Beach. 

A New Jersey Watershed Ambassador deploys a tag onto a horseshoe crab found on Fortescue Beach.

​Our second weekend of tagging in May was met with a similar chill in the air, but also with the promise of warmer weather heading our way. The Society continued to welcome dedicated volunteers to the Bayshore, excited to receive an update on the crabs. At each tagging event, Shane Godshall, Habitat Restoration Program Director, and Kerstin Axe, Habitat Restoration Technician, provided an overview of the fascinating Limulus Polyphemus (Atlantic Horseshoe Crab). Shane & Kerstin touched on the life history of horseshoe crabs, their interactions with humans, and, most importantly, how to deploy the white disc tag to their left side.

A family, sporting their Society gear, poses with a tagged horseshoe crab on Fortescue Beach.

​Our third weekend of tagging in May was finally met with the warmer weather that was promised. Typically, peak horseshoe crab spawning takes place around Memorial Day Weekend. (The crabs flock to the beaches, just like the people do!) The number of crabs observed during our tagging events on Weekend #3 remained lower than expected, at least at those bay beaches in Cumberland County. We believe this may have something to do with the colder bay temperatures that permeated later into the season, due to that early – Spring chill experienced throughout Weekends #1 & #2.

Restoration Corps member Derick Smith assisting Wildlife Restoration Partnerships with the banding of Red Knots on Reeds Beach. Banding assists in the monitoring of Red Knot migration, weight, and breeding.

Conversely, the Cape May County bay beaches were teeming with spawning activity. We believe this may have something to do with the proximity of Cape May County bay beaches to the Atlantic Ocean, which is substantially saltier than the Delaware Bay, and therefore, impacted less by temperature fluctuations from cooler air temperatures & chilly rain events. Society Staff Members, including Kerstin Axe, Charles Werbany, R-Corps Crew Leader, and Derick Smith, R-Corps Crew Member, assisted our partner organization, Wildlife Restoration Partnerships, with banding of the threated Calidris canutus (Red Knot) on Reeds Beach. Early reports show that the birds were well fed.

The sun setting on Thompsons Beach, with volunteers working hard to deploy their allotted 25 tags.

Our first weekend of tagging in June was full of beautiful sunsets, characteristic of the Bayshore. At this point in the season, many volunteers were returning for their 2nd or 3rd event, or had been anxiously awaiting their time with the crabs. The Society also spent some time this weekend celebrating horseshoe crab spawning and migratory shorebird feeding at our annual Sunset on the Bay! It is of essence to note that these tagging events were hindered by abnormally high tides, due to the New Moon, and associated Spring Tide. One tagging event was even cancelled, due to a Coastal Flooding Advisory. ​

Dedicated tagging volunteers, sporting "Anti-Extinction" tees, deploying the final tags of 2026. How do you master evolution? 450 million years of barely trying!

O​ur final weekend of tagging was capped off with the deployment of our 4,000th tag for the season! Volunteers were ecstatic about assisting us in crossing the finish line, and we took a moment to pat ourselves on the back in light of empty boxes of tags. Shane & Kerstin made a point to thank volunteers for their efforts at each & every event. Our tagging program is Staff-Coordinated, but it is also Volunteer-Charged. We are so grateful to those who spend their Friday, Saturday, and Sunday evenings with us on the bay. For now, we bid farewell to our favorite friends, with hopes that next year’s tagging will be just as successful.

Tagging By the Numbers
Thompsons Beach: 1,350 Tags
Kimbles Beach:  575 Tags
Fortescue Beach: 775 Tags
Green Creek Beach: 150 Tags 

A resighted horseshoe crab.

What to Do if you Spot a Tagged Crab
​If you come across a tagged horseshoe crab during your upcoming time on the beach, please report your resight to the U.S. Fish and Wildlife Service! (www.fws.gov/crabtag). This website links to a form, which will allow you to share the Tag #, condition of the crab, and where it was spotted. The USFWS will then share this resight information with the Society, if it happens that the tag was deployed by our volunteer fleet. We value this data, as we use resights as an indication of our restorative success. In other words, if we resight crabs on beaches that we have restored, we know that sufficient spawning habitat has been created

The Habitat Restoration Team 
To echo the sentiments of our Executive Director, Danielle McColluch, we would be remiss to adjust the protections that are in place for crabs after one encouraging season. This is especially true when we consider that this season may not have been truly encouraging – There was the potential for misalignment between the crabs & shorebirds. We are weary of this possibility in each season to come, as we face a changing climate. Additionally, we are experiencing coastal flooding during Spring Tides, which is displacing the sand that has previously nourished our beaches. What can we do? The answer is simple – Continue investing in projects that restore spawning and feeding habitat for crabs and birds, alike. Keep your eyes peeled for next season’s tagging dates, which will be published in April!