There’s so many horseshoe crabs invading Maryland, Delaware shores right now. Here’s why

The prehistoric-looking horseshoe crabs native to the Delmarva Peninsula are on the move for their annual migration down the Atlantic coastline back to Maryland. According to the Maryland Department of Natural Resources, the peak of the horseshoe crab spawn depends on late spring and early summer high tides, culminating on or around each full and new moon in June.