The Western Silvery Minnow . . .

This species has been identified as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is listed under the federal Species at Risk Act (SARA) and was afforded protection under the SARA as of June 2004. Additional protection is afforded through the federal Fisheries Act. Under the SARA, a recovery strategy must be developed for this species.

General Description

Hybognathus argyritis

© J. R.Tomelleri

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
• Averages 76 to 125 mm in length

Distribution

In Canada, the Western Silvery Minnow is endemic in southern Alberta, found only in the Milk River. In the U.S., 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.

Western Silvery Minnow Distribution

Habitat and Life History

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, nonadhesive and hatch within a week in temperatures ranging from 13^o to 20^oC. This species is known to form large schools of 50 to 100 fish and has a lifespan of up to four years.

Diet

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

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.

Similar Species

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 have since been 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: Houston 2001 (COSEWIC Status Report); Alberta Sustainable Resource Development Wildlife Status Report No. 47 2003.

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