Fourhorn sculpin COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

First described by Linnaeus in 1758, the fourhorn sculpin, Myoxocephalus quadricornis, has been subjected to various changes in nomenclature. It has been referred to as Cottus, Oncocottus, Myoxocephalus, and Triglopsis based on morphological characters. Myoxocephalus appears to be the accepted genus in North Americawhereas European authors prefer Triglopsis. A member of the family Cottidae, the fourhorn is commonly called chaboisseau à quatre cornes in French and kanayok in Inuktitut.

Distribution

The fourhorn sculpin occurs as a landlocked relict in cold, deep freshwater lakes of northern North America and northern Europe, particularly in Canada, Finland, Norway, Sweden, and Russia. In Canada, museum records indicate that the sculpin inhabits lakes in the Northwest and Nunavut Territories. The only province where it has been collected is Newfoundland and Labrador.

Habitat

Little has been reported concerning the habitat requirements of the freshwater form. Individuals from Garrow Lake, Little Cornwallis Island, NU, occur in a depth range of 3.8-15.0 m and a salinity range of approximately 3-35 ppt. Adults are benthic and require a soft substrate to spawn.

Biology

Little is known concerning the reproduction and growth of the freshwater form. Garrow Lake specimens have a slower growth rate than marine forms from the Beaufort Sea and Strathcona Sound. The maximum age, the age at first maturity, and the time required for three generations are unknown. Predators of fourhorn sculpins are piscivorous fishes and birds. They do not appear to be a heavily parasitized species in either freshwater or seawater. Fourhorn sculpins feed mainly on benthic invertebrates, small fishes, and fish eggs.

Population sizes and trends

Little is known about the population sizes and trends of the freshwater form. Distributional data is largely confined to presence-absence records. Some authors feel the Garrow Lake population has been adversely affected by pollution from a nearby, recently decommissioned lead-zinc mine and may become extirpated in the next 20 years. Anecdotal information indicates the population to be healthy at present, but comparisons with historic levels are not possible. The lack of information may be attributed to the fourhorn sculpin not being a species of commercial, recreational, or subsistence interest, in addition to the isolation of the high Arctic lakes it inhabits.

Limiting factors and threats

The fourhorn sculpin is of little direct commercial or sport fishing interest, but it may be caught accidentally by recreational fishers. The marine form is used occasionally as food by natives, but it is unknown if the freshwater form is utilized in this manner. The fourhorn sculpin is of special interest to the scientific community concerned with Canadian post-glacial dispersion and zoogeography. The species may be of value as an indicator of environmental quality and could be a key species to monitor in areas of development in the Arctic.

Existing protection or other status

General protection is provided in Canadian waters under the Fisheries Act. There is no listing for this species in CITES, IUCN, or US Fish and Wildlife Service. It is considered ‘Endangered’ in many freshwater lakes in Sweden. The fourhorn sculpin is listed as protected fauna in the summary report of the Convention on the Conservation of European Wildlife and Natural Habitats.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species and include the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal organizations (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biosystematic Partnership, chaired by the Canadian Museum of Nature), three nonjurisdictional members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The committee meets to consider status reports on candidate species.

Definitions (After May 2003)

Species

Any indigenous species, subspecies, variety, or geographically defined population of wild fauna and flora.

Extinct (X)

A species that no longer exists.

Extirpated (XT)

A species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A species facing imminent extirpation or extinction.

Threatened (T)

A species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^Footnote1

A species of special concern because of characteristics that make it particularly sensitive to human activities or natural events.

Not at Risk (NAR)^Footnote2

A species that has been evaluated and found to be not at risk.

Data Deficient (DD)^Footnote3

A species for which there is insufficient scientific information to support status designation.

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list.