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Cusk (Brosme brosme)

Status | Species Description | Habitat | Distribution | Population Trends | Threats | Conservation Efforts | Regulatory Overview | Taxonomy | Key Documents | More Info

Status

ESA Candidate Species - throughout its range
ESA Species of Concern - Atlantic-Gulf of Maine

Species Description

Weight:
up to 20 pounds (9 kg)
Length:
up to 3 feet (1 m)
Appearance:
light grey with hints of brown to a dull reddish brown that transitions to a dirty white on the belly, a single chin "barbel" and single dorsal fin
Lifespan:
about 15 years
Diet:
crustaceans, fishes, and echinoderms
Behavior:
solitary animals, sometimes found in small groups; they spawn in spring to early summer

The cusk is a very unique species of fish and the only one in its taxonomic genus of Brosme. Cusk can be up to 3 feet (1 m) in length and weigh up to 20 pounds (9 kg). They are characterized by a single chin "barbel" and single dorsal fin. Their upper body ranges in color from a light grey with hints of brown to a dull reddish brown that transitions to a dirty white on the belly.

Cusk are relatively slow-growing and late-maturing. Fifty percent of fish mature at approximately 1.5 feet (.5 m) in length when they are about 5 to 6 years old. Females generally mature later than males. The maximum age of this species is believed to be greater than 14 years.

Cusk spawn in spring and early summer. Eggs initially rise to the surface where hatching and larval development take place. Juveniles move to the bottom at 2 inches (5 cm) in length and become sedentary and solitary.

The cusk diet consists primarily of various species of crustaceans, fishes, and echinoderms. Cusk are solitary or occur in small groups.

Habitat

The cusk is a deep water species found in rocky, hard bottom areas to a depth of 100 meters (328 ft) and water temperatures of 30 to 50°F (1-10°C). In the United States, cusk have been found to be distributed primarily in deeper waters in the central portion of the Gulf of Maine.

Distribution

Cusk occur in the Northwest Atlantic from New Jersey to the Strait of Belle Isle and on the Grand Banks of Newfoundland. They are found rarely at the southern tip of Greenland. In the Northeast Atlantic, they occur off Iceland, in the northern North Sea, and along the coast of Scandinavia to the Murmansk Coast and Spitzbergen, Norway.

Population Trends

A declining population trend has been evident since the late 1960s. All abundance indices remained at or close to record-low levels from 1985 through 2002. NOAA's Northeast Fisheries Science Center biomass index for cusk was near zero in 1998. In the early 1970s, individual fish weight averaged 7 lbs (3 kg) but declined by 50% to 1.5 kg (3 lbs) through the late 1990s. Landings and survey indices have dropped considerably from 1984 to 2004. The ratio of landings to biomass estimates has been increasing since 1986, which implies increased exploitation over time.

The catch per unit effort from 1970-2001, or just over 3 cusk generations, declined by about 90% while population estimates for cusk greater than 20 inches (0.5 m) in the same time frame showed a 96% decline (Committee on the Status of Endangered Wildlife in Canada (COSEWIC 2003).

Threats

Conservation Efforts

In the U.S., the cusk fishery is not presently managed. Fishing was unrestricted in Canada until 1999 when limitations were established for landings in the Scotia-Fundy region. In 2004, we made cusk a "species of concern". Species of concern status is meant to draw proactive attention and conservation action to a species from relevant state and federal managers and partners. However, species of concern status does not carry any procedural or substantive protections under the ESA.

Regulatory Overview

Due to concerns over the status of this species, we initiated a status review of this species in March 2007. This status review will be used to determine whether listing of cusk as a threatened or endangered species under the Endangered Species Act is warranted.

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Ophidiiformes
Family: Lotidae
Genus: Brosme
Species: brosme

Key Documents

(All documents are in PDF format.)
Title Federal Register Date
Notice of Initiation of a Status Review under the Endangered Species Act (ESA) 72 FR 10710 03/09/2007

More Information

Updated: January 21, 2015