The Peace/Williston Fish and Wildlife Compensation Program (PWFWCP)

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Brassy Minnow
Hybognathus hankinsoni

What do they look like?

A small (usually less than 70 mm) minnow with a snout that slightly overhangs the upper jaw. Dorsally, it is olive-green and brassy-yellow to dull silvery laterally. It has a darkish lateral band extending from the gill cover to the tail. The dorsal fin originates in front of the pelvic fins. The mouth is small (not extending back as far as the front of the eye), and the scales are large. It is the only minnow in the upper Peace with a dark peritoneum and an intestine with multiple coils. In the Peace system, most erroneous records of brassy minnows (and there are many) are misidentified lake chub.

Where do they live?

In B.C., brassy minnows typically occur in small lakes, small slow-moving streams, beaver ponds, and drainage ditches. In the Crooked River system they usually occur in stained waters but in the lower Fraser Valley they are found in both clear and turbid water. In lakes, adults often are associated with soft, mud bottoms and dense vegetation. In the summer they are rarely observed in water more than 1.5 m deep. In streams, adult brassy minnows remain close to vegetation and appear to avoid water with surface velocities higher than 0.5 m/s. There is no obvious habitat difference between young-of-the-year and adults, except that fry tend to be found in shallower and quieter water than adults.

What is their life like?

In British Columbia, the life history of the brassy minnow is not well known, especially in flowing water. In the lower Fraser Valley, spawning occurs from mid-May (when water temperatures reach about 14 °C) to early June, while in the Price George region spawning starts in early June and continues into early August. Depending on body size, females produce about 100 to 1,000 eggs; however, not all the eggs are released in a single spawning and females probably spawn several batches of eggs over a period of about a week. Spawning occurs in, or near, vegetation, and the eggs either sink to the bottom or are caught up in the vegetation.

Once fertilized, embryo development is rapid (hatching occurs within 70 hours at 18 °C). The newly hatched larvae are small (about 4 mm in length), transparent and lack eye pigment. By day eight they are about six mm long and begin to feed. In the lower Fraser Valley, in some years, there is a second spawning in the fall that produces fish about 15 mm long by mid-November.

Growth in the first months of life is rapid and in Huble Lake, young-of-the-year averaged 27.9 mm (fork length) by early August. In the lower Fraser Valley, populations that disappeared in the summer tend to reappear in the fall (early October). At this time the young-of-the-year average about 42 mm in fork length. Both males and females reach sexual maturity after one winter. The maximum age recorded in British Columbia is four years (3+) and, so far, all individuals of this age were females.

What do they eat?

The long intestine and black peritoneum suggest that plant material is an important part of the brassy minnow's diet. In the lower Fraser Valley, the intestine is usually filled with what appears to be organic detritus, algae and occasional chironomids. A similar diet was observed in Huble Lake which consisted of organic debris, algae, and small insects.

What is their distribution? The brassy minnow is a native North American species with an unusual geographic distribution. It occurs in a belt across the entire central section of the continent (i.e., from the Saint Lawrence system in the east to the Fraser system in the west), and from Fort McMurray, Alberta, to Kansas in the south. Apparently, it is abundant in the south-central part of this distribution but in western Canada (Alberta and British Columbia), populations are widely scattered. Because most of its distribution lies east of the Continental Divide, they were assumed to be an introduction. We now know that this species is widely, albeit sporadically, distributed in the Fraser and Peace systems. This suggests that the brassy minnow probably crossed the Continental Divide from the Peace drainage into the Fraser system sometime during the final stages of ice-retreat. In B.C., the brassy minnow has a scattered distribution in the Fraser and upper Peace systems. In the Fraser system, the brassy minnow is abundant in lakes and sluggish streams near Vanderhoof and Prince George, and in the lower Fraser Valley from Chilliwack to the Fraser Delta (including areas under tidal influence). In the intervening area, however, there is only one confirmed record --- from a beaver pond in the Horsefly River system near the village of Horsefly in central British Columbia. In the upper Peace system the only reliable records are from lakes and streams in the headwaters of the Crooked River by Summit Lake.

View Peace Williston distribution map.