Shore crabs feed primarily on invertebrates such as molluscs, clams, crustaceans and worms, but they eat practically anything they can get a hold of, including the remains of dead organisms. Their voracious appetites have lead to the regional decline of several species. Shore crabs are an invasive species due to their easily accomodated diets and widespread dispersion.
In addition to diminishing the population of several clam species, shore crabs are responsible for greatly reducing the number of crucial bivalve species, including scallops and quahogs. As a result of their diminution of these species, shore crabs have substantial negative impacts on recreational and commercial fisheries. To curb the complete destruction of these species, a number of local and state governments practice shore crab population control. The majority of these practices limit shore crabs to a particular region.
Shore crabs are found all over the world. However, they are most common to the eastern Atlantic seaboard. Ocean currents pass the crabs' larvae from one habitat to another, and the crabs are able to thrive in a number of different environments.
Female shore crabs produce up to 185,000 eggs. Young crabs live in seagrass and seaweed until they reach adulthood. Shore crabs are primarily nocturnal. However, their activity depends on the tide.