The Horseshoe Crab is Delaware's official state marine animal, and our waters are home to more horseshoe crabs than anywhere else.  Our Inland Bays see thousands of horseshoe crabs visit their shores each year.  The health of our Inland Bays is critical for these visitors, many other species, our economy, and us, as humans.

Would you DO MORE to support the Center (and our state marine animal)?  

In 2022, a total of 3,250 horseshoe crabs were tagged.  Our fundraising goal for 2023 is to raise $10 for each tagged horseshoe crab.

For a donation of:
$10:  Help us tag a Horseshoe Crab
$30:  Help us tag 3 Horseshoe Crabs
$100:  Help us tag 10 Horseshoe Crabs

Why horseshoe crabs matter?

How do we complete the tagging/survey?
In May and June, horseshoe crabs travel to sandy beaches in the Inland Bays and congregate in mass spawning events that peak at high tide near the new and full moon. On these peak nights, volunteers move along the beach’s high tide line counting the number of crabs found within one-square-meter “quadrats.” This process is repeated 100 times per beach. Following each survey, a portion of crabs are tagged and released using U.S. Fish & Wildlife Service guidelines.

What our survey work has taught us?
Survey results show that the Inland Bays are heavily used as spawning habitat for horseshoe crabs, with densities of spawning crabs on many beaches approaching those seen in Delaware Bay, which is known as the world's largest spawning site. The proportion of male crabs compared to females in the Inland Bays consistently exceeds the minimum 2:1 ratio needed to ensure healthy genetic diversity. However, while populations of horseshoe crabs in the Inland Bays have apparently remained stable over the past five years, they are still far below historic levels. The critical role of this species in supporting threatened shorebird populations highlights the importance of conserving the natural shorelines that they need in order to grow their populations.

Please consider a donation to Do More to support the mission of the Center to help horseshoe crabs be around for another 445 million years.