National Recognition for Local Scientist Highlights Benefits of Citizen Science Project that Kicks Off on April 10!

Rehoboth Beach, DE – The Delaware Center for the Inland Bays is seeking volunteers for their Annual Horseshoe Crab Survey and tagging citizen science project. The project sends hundreds of volunteers to survey the number of horseshoe crabs found around the sandy beaches of the Inland Bays on each full and new moon in May and June.


Both new and returning volunteers are invited to the training on Wednesday, April 10, 2019, from 4:30-6:30 at the South Coastal Library in Bethany Beach. While attendance at the training meeting is not mandatory, it is very highly recommended as team assignments will be made at this time. Interested participants can register at


Data from the Center’s horseshoe crab survey is used by researchers to better understand the horseshoe crab and to help us measure the importance of Delaware’s Inland Bays to the stability of this iconic “living fossil”. Just last spring, the Andrew McGowan, Environmental Scientist for the Center, had an article published in the national scientific journal: Estuaries and Coasts, titled “Horseshoe Crab (Limulus polyphemus) Movements Following Tagging in the Delaware Inland Bays, USA”. Here, McGowan explored a whole new question about the movements of horseshoe crabs within the Delaware Inland Bays region, and recognizing the importance of citizen scientists to the results of this study: “We could not have done this research without the dedicated citizen scientists who come out every year to tag and record crabs. It’s their efforts that have made this work possible”.


Horseshoe Crabs can be found in many regions along the Atlantic Coast, including the Delaware Bay region, which spans from Barnegat Bay, New Jersey to Chincoteague, Virginia. In all regions, horseshoe crabs are a regular sight each spring near sandy beaches that they use for spawning but their long-term movements after the end of the spawning season are not well-studied.


Using data collected by citizen scientists, McGowan was able to confirm previous studies which demonstrated that long-distance migrations between neighboring regions are rare. “Only two of the more than 1,000 tracked crabs moved from the Inland Bays to the Long Island Sound region, even though the two regions are next to each other,” he explained.


In addition to confirming previous studies, McGowan also completed an original study which focused on the movement of crabs specifically within the Delaware Bay region. The results showed a large amount of movement between bays within this area. The horseshoe crabs in the study stayed close to spawning beaches for about five days, but then often moved from one bay to another in a single year. It was common to see horseshoe crabs that were tagged in the Inland Bays move to the Delaware Bay and occasionally the coastal bays of Maryland, Virginia, or New Jersey. This movement shows how important connected neighboring bays are to the population of horseshoe crabs within a region. Protecting natural shorelines of our own Inland Bays will also help support the health of the larger regional populations.


Volunteers interested in becoming a citizen scientist and helping with research like this, are encouraged to get involved by attending the training on April 10th!

The Delaware Center for the Inland Bays is a non-profit organization established in 1994, and is one of 28 National Estuary Programs. With its many partners, the Center works to preserve, protect and restore Delaware’s Inland Bays and their watershed.

For more information call Amy Barra at (302) 226-8105 x 103, send an email to, or visit us online at

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Posted Under: Staff Blog