Arctic Grayling Recovery Program

Grayling Biology

The Arctic grayling is a close relative of the trout and is distributed in northern latitudes throughout both North America and Europe. Arctic grayling in Montana are the most southernly distributed remnant population - located more than 250 miles from the nearest, intact population in Canada.

With its sail-like dorsal fin dotted with large iridescent purple and reddish spots, the grayling is one of the most unusual and beautiful fishes in Montana. Grayling typically have a dark back with iridescent gray sides and black spots along both sides. The adipose, caudal (tail), pectoral, and anal fins are dusky brown and the pelvic fins are often marked with pink to orange stripes. Grayling have evolved many strategies to meet the needs of life in what are often harsh and uncertain environments. Grayling can be highly migratory, and can utilize different streams for spawning, juvenile rearing, summer feeding, and overwintering. Winter usually finds grayling in lower reaches and deeper pools of major rivers. With the coming of spring, grayling begin an upstream migration to spawning grounds. Like salmon, grayling are believed to return to the same spawning and feeding areas.

After spawning, adult grayling begin a migration to summer feeding areas. Depending on where they have spawned, the distance traveled can be up to 50 miles. During summer months, grayling are aggressive feeders and can be easily caught on dry flies or nymph imitations. Their eagerness to hit a dry fly makes grayling a favorite among dry fly anglers.

Grayling fry hatch about three weeks after spawning, and tend to occupy the quieter waters near where they were spawned. In the early fall, grayling again migrate downstream to reach overwintering areas.

Grayling need good water quality to survive. Sediment inputs can smother eggs, reduce pool quality and contribute to poor water quality. Some nutrient inputs can also have negative inputs by contributing to surface water eutrophication.