Florida Fish and Wildlife Conservation Commission wants people to report where they see the living fossils mating.

Seen some horseshoe crabs publicly in the throes of passion?

Now you can report them.

To the Florida Fish and Wildlife Conservation Commission.

The FWC Reporter app is free to download on Apple or Android smartphones or tablets from the App Store and Google Play.

Spring is peak mating season for the primordial crabs, and commission biologists are encouraging sighting reports. Though members of the 450-million-year-old mate year round, it is most common to see groups along the shore in March and April. To identify mating pairs, look for a smaller male on top of a larger female, the commission advises.

Beachgoers will likely have the best luck spotting horseshoe crabs around high tide, within three days of a full or new moon. The next full moon is Friday, March 2, and the new moon is Saturday, March 17.

Horseshoe crab numbers have declined because of overfishing and loss of habitat.

Observers also can go to MyFWC.com/Contact and go to “Horseshoe Crab Nesting Activity” for the “Florida Horseshoe Crab Spawning Beach Survey” link, report findings through email at horseshoe@MyFWC.com or by phone at 866-252-9326.