Identification & Biology: The cusk, Brosme brosme, is a marine cod-like fish in the ling family Lotidae. It is the only species in the genus Brosme.
It is a slender fish with several rows of sharp teeth that line the fish’s jaws, and a single barbel (or whisker) which adorns the lower jaw. Body coloring varies from reddish- to greenish-brown shading to cream or white on the belly.
Cusk spawn in spring and early summer in both sides of the northern Atlantic. Once the young fry have taken to the bottom they are ground fish so exclusively that they are never seen swimming up to the upper waters. They eat crustaceans and other soft bodied invertebrates and mollusks and are more or less solitary, and not so abundant anywhere as cod, haddock, or hake are.
The cusk is separate from all its relatives at a glance by the fact that it has only one dorsal fin. Also characteristic is the nature of the dorsal, caudal, and anal fins, as they are continuous at the base but separated by very deep notches so that they are obviously distinct.
Range & Habitat: Cusk are distributed in the western Atlantic from Newfoundland to Cape Cod… and on the European side from northern Scotland to Iceland and Norway. They are normally found in water deeper than sixty feet (20 m), and are almost always taken over rough bottoms where rocks, ledges, or gravel are common. A few cusk are caught from party boats by sportsmen hand lining for ground fish, but most of the cusk live too deep to be of any particular interest to anglers.
Market Description: Cusk is a U.S. National Marine Fisheries Service Species of Concern. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration (NOAA), National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act (ESA).
Buying Tips: The cusk’s flesh should be white when raw. It then becomes an opaque white when cooked. The flavor is mild and sweet like cod.
Recommended Preparation: The firm white flesh is a good choice for chowders and stews, and can be substituted for cod or hake.