Northern brook lamprey (Ichthyomyzon fossor) COSEWIC assessment and status report: chapter 2

Executive Summary

Northern Brook Lamprey
Ichthyomyzon Fossor
Great Lakes– Upper St. Lawrence Populations
Saskatchewan– Nelson Population

Species information

The northern brook lamprey is one of six species of the genus Ichthyomyzon. It is eel-like in appearance, reaches approximately 160 mm in length as an adult, and is non-parasitic. Adults can be distinguished from other lampreys by a single dorsal fin and characteristic teeth patterns. Ammocoetes (larval lampreys) within the genus are generally indistinguishable from one another. Some recent genetic analyses have questioned whether this species is truly distinct from the silver lamprey. Although its taxonomic status has been the subject of some debate, this question has not yet been resolved and pending resolution it is herein recognized as a distinct species.

Distribution

Adults have been found in streams throughout Ontario, southwestern Quebec, and southeastern Manitoba. Increased sampling efforts have revealed more locations over the past several years in Ontario. The widespread occurrence of Ichthyomyzon larvae may indicate a much wider distribution, but collection of adults is required to confirm identification.

Distribution in the United States is patchy, but includes Illinois, Indiana, Kentucky, Michigan, Minnesota, Missouri, New York, Ohio, Pennsylvania, Vermont, West Virginia, and Wisconsin.

Habitat

This lamprey is generally found in clear water streams of a wide range of sizes. Larval northern brook lamprey reside in burrows in silt and sand substrate. After metamorphosing into juveniles, the larvae emerge from their burrows and attach themselves to the stream bottom. For spawning, they require a substrate composed of coarse gravel with a relatively swift, unidirectional current.

Biology

A freshwater fish that inhabits stream sediment in their filter-feeding larval stage, it lives for 3 to 7 years burrowed in soft areas of the stream bottom. After transformation, the northern brook lamprey lives from four to six months before spawning and dying, and does not feed at all during its adult stage.

Population sizes and trends

No population estimates have been made for this species. Northern brook lamprey are no longer found in a number of streams around the Great Lakes that historically supported populations. However, large numbers of ammocoetes of this genus, many of which are thought to be northern brook lamprey, are encountered incidentally through assessment of larval sea lamprey.

Limiting factors and threats

Applications of lampricides to habitats where the sea lamprey and northern brook lamprey coexist have caused reductions in populations around the Great Lakes. These applications are conducted periodically to control the invasive sea lamprey, but have inadvertently resulted in native lamprey declines as well. Water level manipulation, water temperature changes, and pollution have been identified as additional threats.

Special significance of the species

This species, as with all lamprey species, is valuable in that they allow investigation of evolutionary history due to their ancient origins. Northern brook lamprey have been used successfully as biomonitors of contaminants. They also may play a role in nutrient cycling.

Existing protection or other status designations

The northern brook lamprey is currently considered a species of Special Concern in Canada. Their habitat is protected under the Canadian Fisheries Act as well as Regulations respecting wildlife habitats in Quebec.

In the United States, they are currently ranked as critically imperiled in Illinois, New York, Pennsylvania, Vermont and West Virginia, imperiled in Kentucky and Ohio, and vulnerable in Minnesota.

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. Species designated at meetings of the full committee are added to the list.  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 for 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 entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species. 

Definitions

Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.

Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A wildlife species facing imminent extirpation or extinction.

Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)Footnotea
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)Footnoteb
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)Footnotec
A category that applies when the available information is insufficient (a) to resolve a species' eligibility for assessment or (b) to permit an assessment of the species' risk of extinction.

Canadian Wildlife Service

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

Page details

Date modified: