The Western Silvery Minnow

Description
Habitat
Threats
Further Information
Scientific Information

Description

The Western Silvery Minnow (Hybognathus argyritis) is a member of the Minnow family, Cyprinidae, and has the following characteristics:

• Yellow with silver sides, a white belly and a faint, broad, mid-dorsal stripe;
• Elongated body with a stout, narrow section just before the tail;
• A short, bluntly triangular head with a rounded snout that overhangs the subterminal mouth;
• The dorsal, anal and pelvic fins each contain eight rays;
• Pectoral fins are relatively short with 15 or 16 rays;
• Caudal fin is forked; and
• Averages 76 to 125 mm in length.

Hybognathus argyritis

Illustration by: Joseph R.Tomelleri

Habitat

In Canada, the Western Silvery Minnow is endemic in southern Alberta, and is found only in the Milk River. In the United States, this fish occurs in the Mississippi River Basin, from the mouth of the Ohio River north to the Missouri Basin and Milk River in Montana.

The Western Silvery Minnow is typically found in the plains in quiet water with low velocity, such as in the backwaters and pools of larger streams. It prefers sandy bottoms but frequents areas of gravel, muck or debris-covered substrate. Spawning is believed to occur in May in shallow waters. Females begin spawning in their first year; males do not spawn until two years of age. The eggs are 1 mm in size, non-adhesive and hatch within a week in temperatures ranging from 13º to 20ºC. This species is known to form large schools of 50 to 100 fish. The Western Silvery Minnow has a lifespan of up to four years.

The diet of the Western Silvery Minnow is believed to consist of benthic diatoms and algae, and other organic matter originating from bottom detritus.

The map indicates the distribution of the Western Silvery Minnow in southern Alberta.

Threats

Given its limited distribution, the survival of the Western Silvery Minnow in Canada may be particularly susceptible to a number of threats including siltation, changes in water flows and levels, prolonged drought and introduced pollutants.

Further Information

The Western Silvery Minnow, along with the Eastern Silvery Minnow (H. regius), were once believed to be subspecies of the Central Silvery Minnow (H. nuchalis). However, they are now considered distinct species due to morphological differences. In addition, the Western Silvery Minnow is similar to the Plains Minnow (H. placitus) and the Brassy Minnow (H. hankinsoni).

Text Sources: Alberta Sustainable Resource Development Wildlife Status Report No. 47 2003; COSEWIC Assessment and Update Status Report 2008.

For more information, visit the SARA Registry at www.SARAregistry.gc.ca.

Scientific Information:

Scientific Name: Hybognathus argyritis
SARA Status: Threatened (June 2003)
COSEWIC Status: Endangered (April 2008)