Jonah Crab

Cancer borealis

The Jonah crab (Cancer borealis) is a large, heavily built crab found along the northwestern Atlantic coast. Adults reach a carapace width of 15-22 cm and display a yellowish to reddish-brown, roughly oval carapace with coarsely toothed edges. Their robust claws have black tips and are powerful enough to crack open mollusks and sea urchins. They inhabit rocky reefs, boulder fields, and offshore banks at depths of 0-800 meters, though most commonly encountered by divers between 5-50 meters. They are omnivorous predators and scavengers feeding on mollusks, sea urchins, crustaceans, and algae. They are often found sheltering in rock crevices and under boulders during the day, emerging at night to forage. Their large size and imposing claws make them an impressive sight for divers in New England and Maritime Canadian waters. They have become increasingly important commercially as an alternative to declining American lobster stocks.