Cycle 1 — 2025

CSHH Horseshoe Crab Monitoring Outcomes

Night 1:

The start of horseshoe crab monitoring season, two days before the full moon. Since it was nearing a full moon, we expected to see a good amount of horseshoe crabs, but we were in for a surprise. We counted a total of 340 horseshoe crabs!

Additionally, we deployed 25 US Fish and Wildlife tags, making this the first time that horseshoe crab-monitoring tags were deployed in Hempstead Harbor.

Night 2:

The night of the full moon, we counted 454 horseshoe crabs, deployed ten tags, and had three tag recoveries! Tagging is an important part of monitoring since this can show where horseshoe crabs venture to once they are tagged.

Night 3:

Two days after the full moon. This was a wet, but eventful night for us. We counted 472 horseshoe crabs, deployed ten tags, and had two tag recoveries (one of which was from another waterbody and deployed several years ago)! We also observed a black skimmer, a visitor to the harbor, flying above the water skimming the surface for food. Several lion’s mane jellyfish were seen on all three nights.

Photo slideshow incudes: tagged horseshoe crab with algae on its shell, mating horseshoe crabs along the shoreline, newly tagged horseshoe crab, tagging a horseshoe crab, CSHH staff and volunteers, a horseshoe crab that was “recovered” with an old tag from several years ago and originally tagged in another waterbody (photos by Michelle Lapinel McAllister and Sarah Stromski from monitoring on 5/10/25, 5/12/25, and 5/15/25)