Horseshoe crabs are not actually crabs, but ancient marine arthropods more closely related to spiders. This unusual creature has been around for more than 250 million years – and every spring, many of them come to the shores of the Damariscotta River estuary to lay their eggs.

Ongoing since 2009, the goal of Coastal Rivers’ horseshoe crab count is to track population changes over time. This in turn provides insight into the overall health of the estuary.

The count takes place daily between May 1 and June 15 at the diurnal high tide.