A cusk, or Brosme brosme, is a fish in the Lotidae family. It is also known as tusk, brismak, moonfish, torsk, and brosmius. This cod-like fish is distinguishable from others in the group by its single dorsal fin. Their dorsal, caudal, and anal fins are separated by deep notches. This fish is a bottom-dweller found in the Northern Atlantic, primarily in the Gulf of Maine and Western Scotian Shelf.
The cusk reaches a mature length of about one and a half feet (45.72 cm) at around five to six years. Males tend to be a bit smaller than females. The largest cusk have reached three feet (91.44 cm) in length and 30 pounds (13.61 kg) in weight. They are gray to brown on the top of their bodies, and have dull white, mottled undersides. The younger fish of this species have vertical yellow bands along their sides.
Spawning takes place in April through July. The eggs float to the surface of the water, where the young cusk stay until they are about two inches (5.08 cm) in length. Adults spend their lives at the bottom of the ocean, at least 100 to 300 feet (30.48 to 91.44 m) down. They are commonly found around structures, such as large rock piles.
Adult cusk prefer temperatures of 34° to 45° Fahrenheit (1.11° to 7.22° Celsius). They are seldom seen in seasons other than fall and spring, and they feed on crabs, mollusks, other fish, and whatever else they happen to come across. These fish do not move quickly, even when catching prey. Their lifespan is unknown, but thought to be more than 14 years.
Due to their solitary and sedentary nature, they are difficult to catch. They are typically found while fishing for cod, haddock, or pollock. The best baits to use are clam, shrimp, and chunks of herring. They move slowly and will not chase the bait.
Since 2003, the cusk has been listed as a threatened species in Canada. It was estimated that the population had declined 90 percent since 1970. The United States National Marine Fisheries Service has concerns about the population levels, but maintains that there is not sufficient information to add the cusk to the list of endangered species.
Similar in flavor to cod and haddock, cusk are popular as food. They are sometimes sold as cod, since cod are more popular, and can replace cod in recipes. The mild-flavored flesh falls into large flakes when cooked. This fish is popular fried and in fish chowders. They can also be stuffed and cooked whole.