In Canada, cusk are found primarily in the Gulf of Maine and on the southeastern edge of the Scotian Shelf. The fish seem to prefer water that is more than 200 metres deep, sometimes swimming to depths of 600 metres. Cusk inhabit areas with a hard, rocky sea floor. They are occasionally found over gravel and mud, but rarely over sand.

Essentially northern, deep-water fish, cusk are relatively slow-growing and late-maturing. Males reach sexual maturity at around five years of age; females at seven. A cusk has an elongated body, a large head and a wide mouth. Several rows of sharp teeth line the fish's jaws, and a single barbel-or whisker-adorns the lower jaw. Body colouring varies from reddish- to greenish-brown shading to cream or white on the belly.