The Jonah crab (Cancer borealis) is a marine brachyuran crab that inhabits waters along the east coast of North America from Newfoundland to Florida. Jonah crabs possess a rounded, rough-edged carapace with small light spots, and robust claws with dark brown-black tips. The maximum reported carapace width for males is 222 mm, while females rarely exceed 150 mm
Habitat and Seasonal Movement
Jonah crabs have been reported at depths of up to 750 m. Habitat preferences for Cancer borealis range from rocky substrate in Rhode Island and the Gulf of Maine to silt and clay substrate on the continental slope. It is widely accepted that this species moves offshore in the fall and winter, and females have been documented moving inshore in late spring and summer.
According to stomach content analysis on individuals from the Gulf of Maine, the diet of Cancer borealis consists of mussels, arthropods, snails, and some algal species. Blue mussels (Mytilus edulis) composed more than 50% of analyzed stomach contents.
Jonah crabs have long been caught as bycatch in lobster traps. In the past twenty years, particularly in New England, landings have increased due to increased fishing pressure and market demand. Landings of Cancer borealis in the United States rose from 2-3 million pounds annually in the 1990s to more than 17 million pounds in 2014. In 2014, 70.05% of landings came from Massachusetts, followed by Rhode Island with 24.43%. Jonah crabs are not managed federally in the United States, but instead are managed by individual states. An Interstate Fishery Management Plan was published in August 2015 by the Atlantic States Marine Fisheries Commission 
- Haefner, Paul (1977). "Aspects of the biology of the jonah crab, Cancer borealis Stimpson, 1859 in the mid-Atlantic Bight". Journal of Natural History 11 (3): 303–320. doi:10.1080/00222937700770221.
- Rochibaud, DA; Frail, C (2006). "Development of Jonah crab, Cancer borealis , and rock crab, Cancer irroratus , fisheries in the Bay of Fundy (L FAs 35-38) and off southwest Nova Scotia (LFA 34): from exploratory to commercial status (1995-2004)." (PDF). Can. Manuscr. Rep. Fish. Aquat. Sci. 2775 (iii): 48 pp.
- "Interstate Fishery Management Plan for Jonah Crab" (PDF). Atlantic States Marine Fisheries Commission. Retrieved 27 October 2015.
- Donahue, Megan; Nichols, Allison; Santamaria, Carlos; League-Pike, Paloma; Krediet, Cory; Perez, Kestrel; Shulman, Myra. "Predation Risk, Prey Abundance, and the Vertical Distribution of Three Brachyuran Crabs on Gulf of Maine Shores". Journal of Crustacean Biology 29 (4): 523–531. doi:10.1651/08-3061.1.