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

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Brook Trout
Salvelinus fontinalis

Brook trout are not native to the Williston Reservoir watershed and only non-reproductive strains are stocked into closed lakes (i.e., lakes without direct connections to other waters). The intent here is to prevent any interbreeding with the closely related native char species - Dolly Varden, bull trout, and lake trout).

What do they look like?

Like all char, brook trout have light spots along their flanks. In adults the spots are red or pink and some on the lower flanks are surrounded by bluish halos. Brook trout differ from native char in having wavy light-green marks (vermiculations) on the back, although occasionally both Dolly Varden and bull trout approach this colour pattern. In brook trout, however, the dorsal fin is also heavily marbled with dark wavy lines; in native char the dorsal fin is either uniformly dusky or has pale spots. Fry and parr (less than about 70 mm) lack vermiculations on the back. They still have dark spotted dorsal fins or, in fry <50 mm, the ventral portions of some dorsal rays are dark.

Where do they live?

Like most char, brook trout prefer cool water; however, their upper thermal tolerance appears to be wider than that of native char. Adults can tolerate temperatures ranging from near 0 °C to about 22 °C but grow and survive best at temperatures between 13 and 19 °C. Adult brook trout use a wide assortment of habitats: small streams, large rivers, beaver ponds, and lakes. In the upper Peace, however, all brook trout populations are lacustrine.

In general, brook trout lake habitat use is influenced by the presence of other salmonids. When other species forage in the littoral zone, brook trout tend to be less abundant. Additionally, adult brook trout exhibit a nocturnal activity pattern during the summer. During daylight hours adults remain at inshore focal sites; at dusk they leave their focal site and actively forage throughout the night. Then at dawn, they return to their daytime focal site.

What is their life like?

Although brook trout were introduced into British Columbia almost 100 years ago, their biology has not been studied in the province. Within its native range brook trout exhibit considerable intra- and inter-population life-history variation. The extent of life-history variation in self-sustaining B.C. populations is unknown.

Like other char, brook trout spawn in the fall, usually when water temperatures drop below about 11 °C (late September or October); however, the migration of adults to spawning sites can begin as early as late-July. Spawning occurs in both streams and lakes.

In lakes and beaver ponds, brook trout usually spawn at sites where there is upwelling or subsurface flow. Typically, lacustrine redds are found close to shore in water about 1 m deep. In the upper Peace system (Dina Lake #1) brook trout were observed on spawning sites in the lake. The sites were on a coarse gravel substrate within about 50 m of the inlet stream, close to shore, and in about 1 m of water. Although not measured, there was probably subsurface flow at these sites. A wide range (sand and silt up to cobbles) of spawning substrates is used in lakes and ponds.

Depending on female size, fecundity ranges from about 100 to 5,000 eggs. Growth rate of young-of-the-year brook trout in streams and lakes is variable and depends on temperature, productivity, and intra- and inter-specific interactions. Within their natural range, wild brook trout are relatively short-lived and fish over three or four years old are rare. In these short-lived populations, males typically mature at 1+ (end of their second growing season) and most females mature a year later (2+).

What do they eat?

In lakes, underyearling brook trout consume zooplankton (e.g., ostracods, cladocerans, and copepods). The diet of adults is varied and there appear to be "pelagic" and "benthic" specialists. The pelagic specialists forage in open water and feed primarily on water column prey (plankton) while the benthic specialists forage in the littoral zone and feed primarily on snails, leeches, and dragon fly nymphs. The diet changes with seasons and, like many trout and char, fish can be an important winter prey.

What is their distribution? Brook trout are an eastern North America species. Originally they ranged from the southern Appalachian Mountains in Georgia north to Labrador and Ungava and west in the Great Lakes region to eastern Minnesota and northern Manitoba. Like many popular recreational species, brook trout have been introduced widely and now occur in cool waters in New Zealand, Africa, South America, and Eurasia. They were introduced into western North America in the late 19 th century. Brook trout were introduced into British Columbia in the 1920s and are now established in all parts of the province except for Queen Charlotte Islands, most short coastal rivers, and most of the upper Yukon and Mackenzie systems.

View Peace Williston distribution map.