NYC Audubon Conservation Biologist Debra Kriensky breaks down the horseshoe crab numbers from this year’s monitoring efforts in Jamaica Bay
We are happy to report that 2016 was a great year for horseshoe crabs in Jamaica Bay!
New York City Audubon once again went out during the new and full moons in May and June to count and tag spawning horseshoe crabs. This was our eighth year collecting data on horseshoe crabs in Jamaica Bay, part of a larger project run by the New York State Department of Environmental Conservation and Cornell University Cooperative Extension.
In 2015, a colder than usual spring resulted in unusually low counts at some of our beaches, such as Plumb Beach East. This year, however, the shores were full of mating horseshoe crabs and our counts indicate that numbers continue to stay relatively stable in Jamaica Bay. This is great news, given how important horseshoe crab eggs are to the migratory shorebirds that come through New York City each spring on their way north.
With the help of 163 volunteers (a record!), we were able to count spawning horseshoe crabs at four locations: Plumb Beach East, Plumb Beach West, Big Egg Marsh, and Dead Horse Bay. Spawning activity peaked during the full moon around Memorial Day this year. The high counts were 205 crabs at Plumb Beach East, 21 crabs at Plumb Beach West, and 451 crabs at Big Egg (and that was only what we counted in our quadrat samples!). At Dead Horse Bay, where we take a total count of the horseshoe crabs, the high count was 493.
We were able to tag 797 crabs this year, making a total of 3,835 horseshoe crabs tagged since we started in 2009. We had 80 re-sightings of tagged crabs this year – 55 of which were tagged earlier in the spawning season, indicating that many of the horseshoe crabs we see stick around at the same beach for several nights and even weeks.
We also saw two crabs we had tagged in 2015, two we had tagged in 2014, and one had tagged in 2013! In addition to all of these horseshoe crabs that are returning to the same beach night after night and year after year, we also saw 20 tagged crabs that were put out by other organizations. It will be interesting to eventually find out where and when they were tagged.
If you ever spot a tagged horseshoe crab, write down the number and report where and when you found it to the U.S. Fish & Wildlife Service here.
Thank you to all the amazing volunteers who came out to count with us this year, especially our dedicated volunteer site coordinators, who make it all possible! We’re also very thankful to Patagonia, Williams Partners, and Investors Foundation for their generous support of this year’s horseshoe crab and shorebird work.
We’re already excited for next year’s spawning season! We hope to have another record number of volunteers for next year’s counts. Please email firstname.lastname@example.org if you are interested in getting involved in this important (and fun!) citizen science study.