What is a critical habitat for Horseshoe Crabs?

The answer to this question is actually quite complex because the horseshoe crab requires different habitats during different life stages. The adults need coastal beaches with just the right combination of beach height and tides in order for them to move onshore and mate starting in May of every year. Eggs remain buried in the sand until they hatch. Hatchlings can remain in the sand or be carried along by currents until they reach their first or second post-hatch molt.

These little ones then generally live in sediments in quiet coastal areas. As they get to be yearlings (one year olds) they live in relatively quiet protected beach areas where they will forage on the surface. The picture above shows the tracks made by one-year old horseshoe crabs on a local beach. If you look at the photo really closely you may even spot a horseshoe crab or two.

As horseshoe crabs grow older they move to other coastal areas with stronger tides and different types of food available to them. Once they reach three years old or more they join their adult counterparts and live in the subtidal waters off the coast as well as in shallow waters near the shoreline.