Posts tagged ‘shorebirds’

Jamaica Bay Horseshoe Crab Population Monitoring and Tagging 2018 Recap

Conservation Biologist Kaitlyn Parkins Recording Horseshoe Crab Data at Dead Horse Bay

Conservation Biologist Kaitlyn Parkins Recording Horseshoe Crab Data at Dead Horse Bay

This summer NYC Audubon reached a milestone—10 years of Horseshoe Crab spawning surveys in Jamaica Bay! During the full and new moons in May and June, NYC Audubon conservation staff and dedicated volunteers ventured out at night to count and tag spawning Horseshoe Crabs, a critical food source for shorebirds like the threatened Red Knot. Nearly 200 community scientists braved the unpredictable weather and late nights to help with monitoring at Jamaica Bay this year, including groups from Patagonia, the Metropolitan Society of Natural Historians, P.S. 9 Teunis G Bergen, and the Trinity School. Our Horseshoe Crab monitoring and tagging efforts are part of a larger project run by the New York State Department of Environmental Conservation and Cornell University Cooperative Extension.

 

Horseshoe Crab Monitoring Volunteers Use Quadrat Sampling Rectangles to Collect Standardized Data at Locations Separated by Vast Distances along the Beaches. Photo © Andrew Martin

Horseshoe Crab Monitoring Volunteers Use Quadrat Sampling Rectangles to Collect Standardized Data at Locations Separated by Vast Distances along the Beaches. Photo © Andrew Martin

Our preliminary results indicate Horseshoe Crab numbers are remaining stable in Jamaica Bay. Overall spawning peaked around the full moon on May 29. Spawning activity numbers at Big Egg Marsh this year were more than double the area’s 2017 numbers, making it this year’s most active beach. Big Egg Marsh also peaked slightly earlier than the other beaches, with 326 crabs in our quadrat sampling on May 17. On June 28, despite adult crabs being scarce, Big Egg Marsh volunteers reported thousands of tiny, newly hatched Horseshoe Crabs in the surf.

 

Spawning activity declined slightly at Plumb Beach East and West. Plumb Beach East had a peak 185 crabs in quadrat sampling on May 29, while Plumb West had a high count of 30 crabs in quadrats on May 31. Dead Horse Bay’s numbers were the highest they have been in four years, with 2,200 total crabs found on the beach on the night of May 31. Dead Horse Bay is a “full count” where we count every crab on the beach instead of taking quadrat samples, so it took volunteers until 12:30am to count them all!

Horseshoe Crabs Found at Dead Horse Bay, May 17, 2018

Horseshoe Crabs Found at Dead Horse Bay, May 17, 2018

We were also able to tag 800 Horseshoe Crabs this year, bringing the total number of crabs tagged throughout the program’s 10-year history to 5,980! Of those 800, 82 crabs were resighted later in the season at the same beach. We also spotted 11 crabs that had been tagged in Jamaica Bay by NYC Audubon in previous years; six of these were tagged in 2017, two in 2016, and three in 2015. Six crabs were spotted at Jamaica Bay that had been tagged elsewhere: Fire Island, Long Island, in 2012; Breezy Point, Queens, in 2012; Pikes Beach, Long Island, in 2015; Pikes Beach, Long Island, in 2016; and two from Calvert Vaux Park, Brooklyn, in 2017. These tag resightings help us learn about the importance of Jamaica Bay to the overall New York State Horseshoe Crab population.

Horseshoe Crab Tagged "403854" at Plumb Beach West. Photo © Andrew Martin

Horseshoe Crab Tagged "403854" at Plumb Beach West. Photo © Andrew Martin

This important work would not be possible without the dedication of our site coordinators Andy Martin, Christine Nealy, Ann Seligman, and Dottie Werkmeister. We also thank Patagonia, The U.S. Fish and Wildlife Service Neotropical Migratory Bird Conservation Act grant program, National Park Service, Elizabeth Woods and Charles Denholm, and NYC Parks for their support of this year’s monitoring.

Horseshoe Crab Monitoring Volunteers at Big Egg Marsh on June 28, 2018

Horseshoe Crab Monitoring Volunteers at Big Egg Marsh on June 28, 2018

Horseshoe Crab Monitoring 2016 Recap and Results

NYC Audubon Conservation Biologist Debra Kriensky breaks down the horseshoe crab numbers from this year’s monitoring efforts in Jamaica Bay

 

Horseshoe Crabs Photo by NYC Audubon

Photo: NYC Audubuon

We are happy to report that 2016 was a great year for horseshoe crabs in Jamaica Bay!

 

New York City Audubon once again ventured 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.

Volunteers Counting Horseshoe Crabs, Photo by Tracy Pennoyer

Volunteers Counting Horseshoe Crabs, Photo by Tracy Pennoyer

We were able to tag 797 crabs this year, making a total of 4,380 horseshoe crabs tagged since we started in 2009. We had 78 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 nine 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 10 tagged crabs that were put out by other organizations. So far, we know that one was tagged last year in Cliffwood Beach, NJ and another was tagged in 2012 at Breezy Beach in the Rockaways. It will be interesting to eventually find out where and when the others 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.

Tagged Horseshoe Crab Photo by NYC Audubon

Horseshoe Crab Tagged "341401"

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, the Williams Companies, and Investors Bank 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 volunteer@nycaudubon.org if you are interested in getting involved in this important (and fun!) citizen science study.