Silver Chub

Macrhybopsis storeriana

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Non-active
NA
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Non-active NA
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

* The Silver Chub has been recently reassessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Currently it is considered a single population, and is listed as Special Concern. In 2012, COSEWIC split the populations into two separate units: 1) the Saskatchewan - Nelson River; and 2) the Great Lakes - Upper St. Lawrence. The Saskatchewan - Nelson River populations are not considered to be at risk, while the Great Lakes – Upper St. Lawrence populations are assessed as endangered (see Silver Chub (Great Lakes – Upper St. Lawrence populations))

A change in the legal status of the Silver Chub under the Species at Risk Act is now under consideration.

Description

The Silver Chub (Macrhybopsis storeriana) is a member of the Minnow family (Cyprinidae), and is the only species of the genus Macrhybopsis in Canada. It has the following characteristics:

  • Body is stout and thick;
  • Average length is 100 to 150 mm long; maximum length is 231 mm;
  • Coloured pale grey-green on the back, becoming silver on the sides and silvery white below; a faint lateral band is usually present;
  • Moderate-sized subterminal mouth, and a snout that projects beyond the mouth;
  • Slender barbel, usually present at the end of the maxillary (corner of the upper jaw); eye diameter is relatively large; and
  • Caudal fin is distinctly forked and lightly pigmented, except for lower three-to-four rays, which are white.

Habitat

The range of the Silver Chub extends from Lake Winnipeg, east into the Great Lakes basin, and then south, largely through the Mississippi River system from Minnesota to the Gulf of Mexico. In Canada, the Great Lakes - Upper St. Lawrence populations are found in the Great Lakes basin, limited to Lake Erie and Lake St. Clair and the extreme southern portion of Lake Huron. The Saskatchewan-Nelson River populations (reassessed in 2012 as “Not at Risk”) are found in southern Lake Winnipeg and in the Assiniboine and Red river drainages of Manitoba, North and South Dakota and Minnesota.

In Ontario, Silver Chub is found in large lakes and connecting rivers at depths of 7.6–12 m, although they have been caught as deep as 20 m. Substrate is typically silt or sand, but the species is also sometimes associated with hard substrates, such as gravel, rubble, boulder or bedrock. It is not typically associated with aquatic vegetation. Reproduction of the Silver Chub is poorly understood. Individuals mature at age 1, and live to 3-to-4 years of age. One female can produce as many as 12,000 eggs. Silver Chub spawn in spring or early summer (May to July) at water temperatures between 19-23°C; however, there is uncertainty regarding where the species spawns and its spawning habitat requirements. In Lake Erie, the species has been observed to leave open water and move into nearshore areas in early spring, possibly to begin spawning.

Threats

The Silver Chub was considered common in Lake Erie until the 1950s. Its rapid decline in the 1960s coincided with habitat degradation and eutrophication caused by urban and agricultural runoff. The effects included poor water quality, extensive algal blooms and depleted oxygen levels in the water. Effects on invertebrate populations reduced prey sources. Although some threats have decreased in recent years (e.g. nutrient loading in Lake Erie), many still exist. Recent threats include aquatic invasive species, baitfish harvesting and climate change. Recent studies also suggest that the population numbers have dropped substantially in the past decade, and the risk of extirpation (i.e. extinct in Canada) is high.

Species at Risk (SARA) Public Registry Profile.

Silver Chub

Silver Chub (Macrhybopsis storeriana)

Macrhybopsis storeriana
© J. R. Tomelleri

Scientific Name: Macrhybopsis storeriana
SARA Status: Special Concern (June 2003)
COSEWIC Status: Non-Active
Region: Manitoba, Ontario

Silver Chub distribution in Canada

Map showing the distribution of the Silver Chub in Canada.

Did You Know?

The Silver Chub was considered common in Lake Erie until the 1950s. Its decline there coincided with declines in prey such as mayfly nymphs. A stable population of Silver Chub, one of the few remaining in North America, occurs in the Assiniboine and Red Rivers in Manitoba.

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