Pennask Lake Rainbow Trout

Origin: Located approximately 50 kilometres east of Merritt on the Thompson Plateau, Pennask Lake lies within the Upper Spahomin watershed. Although the lake has low productivity, it has always maintained a large monoculture (single-species) population of small rainbow trout (Oncorhynchus mykiss). A permanent egg-collection station has operated on Pennask Creek, the major inlet stream, since 1927.

Habitat: Pennask Lake is naturally devoid of other fish species. As a result, the trout’s natural prey are mainly aquatic and terrestrial insects. Since Pennask rainbow trout have evolved in this environment, they grow and survive most successfully in highly productive (food-rich) monoculture lakes of the Plateau area where they do not have to compete with other fish species. Within any lake, this strain is pelagic, preferring deep open water. Another key trait of Pennask Lake rainbow is their exceptional ability to conserve body fat. This allows them to survive long winters, and makes them ideal for stocking cold, high-elevation lakes.

Description: Rainbow trout in Pennask Lake are generally small at maturity. However, when stocked into productive monoculture lakes, they grow well and reach a much larger size before maturity. Typical for Interior trout, these fish are lightly spotted on the body, mostly along the back and tail.

Fishing: Most active at dusk, Pennask rainbow are mid-water foragers that feed primarily on benthic (bottom) organisms like chironomid pupae or cladocerans (water fleas). The trout are not highly piscivorous (fish-eating), and show no evidence of preying on non-salmonid fish until they are at least two years old. Pennask rainbow trout have a reputation for being very aggressive, and are world-renowned for their fighting ability and tendency to jump when hooked. And, because this strain focusses on invertebrate prey, experienced fly-fishers often prefer the Pennask rainbows to other strains of stocked rainbows