Spotted sucker (Minytrema melanops) COSEWIC assessment and status report: chapter 2

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COSEWIC Executive Summary

Species Information

A medium-sized catostomid (sucker) averaging between 230 and 380 mm in length. The dorsal surface is brown to dark green, the sides silver to bronze and the ventral surface white and silvery. Spotted suckers are distinguished from other catostomid species by the presence of 8-12 parallel rows of dark spots on the base of the scales.

Distribution

The Spotted Sucker is restricted to the fresh waters of central and eastern North America. In the Great Lakes basin, the Spotted Sucker occurs in the drainages of Lake Huron, Lake Michigan, Lake Erie and Lake St. Clair. It is also found throughout much of the Mississippi River basin and along the lower coastal plain from Texas to North Carolina. In Canada, it is restricted to the extreme southwest portion of Ontario. Less than 5% of the species’ global range is found in Canada.

Habitat

The Spotted Sucker usually inhabits long deep pools of small to medium-sized rivers over clay, sand or gravel substrates. It has also been collected from a variety of other habitats including large rivers, oxbows and backwater areas, impoundments and small turbid creeks.

Biology

During late spring to early summer, Spotted Suckers spawn over clean riffle habitats. Spotted suckers in Missouri reach maturity at age 3. Descriptions of age of maturity and other demographic parameters for Canadian Sspotted Ssucker populations are lacking. Spotted suckers feed on a variety of invertebrate prey: mollusks, copepods, chironomids,and diatoms.

Population Sizes and Trends

No studies examining population size or trends have been conducted on Canadian populations. Between 1962 and 1992, 24+ Sspotted Ssucker were collected from Canadian waters. Since 1992, 67+ specimens have been collected. These collections include 4 new locations: the Canard River, Maxwell Creek (Lake St. Clair drainage), Whitebread Drain (Lake St. Clair drainage) and Bear Creek (North Sydenham River drainage).

Limiting Factors and Threats

Habitat degradation, pollution, siltation and dams are likely detrimental to the well  being of the Spotted Sucker. In the northern portion of their range, temperature is also a probable limiting factor.

Special Significance of the Species

There is no commercial significance to the Spotted Sucker in Canada, nor is it an economically important forage fish. Its continued survival, along with other species at the northern edges of their ranges in Canada, is an indication of good water quality and habitat condition.

Existing Protection or Other Status Designations

The Spotted Sucker was recognized by COSEWIC as a vulnerable (equivalent to special concern) species in Canada in 1983 and was reconfirmed as such in 1994, and again in 2001. In Ontario, the Spotted Sucker was listed as vulnerable in 2000. The Spotted Sucker is globally secure. However, in the United States, population declines have been reported in the northern portion of its range. It is listed as a species of special concern in Kansas and Pennsylvania.

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 agencies (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 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 (NOVEMBER 2004)

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 it 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)*

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) **

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)***

A wildlife species for which there is inadequate information to make a direct, or indirect, assessment of its risk of extinction.

* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
** Formerly described as “Not In Any Category”, or “No Designation Required.”
*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994.

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