TAMPA, Fla. (WFLA) — Dozens of horseshoe crabs took over a Florida beach just in time for spring break, according to the Florida Fish and Wildlife Conservation Commission.

Researchers said horseshoe crabs gather on beaches across Florida to complete their ancient mating ritual dating back 450 million years. Horseshoe crabs mate by pairing up. The smaller male attaches to the larger female before the pair crawl onto the beach.

FWC said the horseshoe crabs mate year-round, but it’s most common to see them in large groups in March and April as well as September and October. The crabs look for sandy, lower wave action beaches.

“Beachgoers will have the most luck spotting horseshoe crabs around high tide within a few days of a new or full moon,” FWC said in a Facebook post. “The best time to get lucky spotting them is within a few days of a new or full moon and around high tide, so the time is now, because the moon is at its fullest St. Patrick’s Day night.”

FWC said sightings can help scientists gather valuable information that may help the long-term success of the species. To report a horseshoe crab mating sighting, click here.

“If you see a horseshoe crab on its back, you can help it flip back over by gently picking it up (holding both sides of the shell), turning it over and releasing it back into the water,” FWC added. “Simple actions such as this help conserve this species and the many other species that depend on it.”