Rainbow Trout (Athabasca River populations)

Oncorhynchus mykiss

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

Rainbow Trout (Oncorhynchus mykiss) are a part of the Salmonidae family of fish, making them close relatives of both salmon and arctic char. In Canada, these strikingly-coloured fish are found in two forms: sea-run populations in the Pacific Ocean (“steelhead”) and the smaller, landlocked (freshwater) variety. Rainbow Trout are named for their silver-coloured bodies, marked with spots and a shimmering pink or red line along their sides. Other common names for this fish are Truite arc-en-ciel (French) and Kinasoo or Namikos (Cree, Plains and Woodland).

Athabasca Rainbow Trout are a distinct population of Rainbow Trout, and are much smaller than any other form of this fish. Considered a “remnant population” from the last ice age, it is thought the Athabasca Rainbow Trout has managed to survive in its unique coldwater habitat by maintaining some juvenile features, such as its ‘dwarfed' size and “parr” marks, into adulthood.

Athabasca Rainbow Trout also have the following features:

  • long, slender bodies, generally silver coloured on their sides;
  • dark blue to olive backsides and white undersides;
  • flanks and fins (including their tail) are sprinkled with dark spots;
  • horizontal pink or red line along the sides of their bodies;
  • can reach maximum lengths of 50 cm and maximum weights of 1.25 kg; and
  • set of 8–12 “parr” marks (oval-shaped marks) along their backs that camouflage them with surrounding boulders and cobble which are likely adaptations against predation.

Athabasca Rainbow Trout share many similar features with the Columbia Redband Trout (Oncorhynchus mykiss gairdneri) and the Westslope Cutthroat Trout (O. clarkii lewisi), which are commonly confused with each other.

Habitat

Athabasca Rainbow Trout are geographically separated from other native Rainbow Trout in North America by the continental divide. On the east side of the continental divide, native Rainbow Trout are present in three separate drainages—Athabasca, Peace and Liard—and there is no movement of fish between these drainages.

Athabasca Rainbow Trout are found in the streams and main rivers of the Athabasca River system of Western Alberta. In their natural habitat, they prefer cold, clear water with fast currents and are generally found in waters at 900–1,500 metres above sea level. Adult Athabasca Rainbow Trout live in riffle, runs, glides and pool structures of headwaters, and tend to occupy deeper and faster moving water than juveniles.

Athabasca Rainbow Trout spawn in the spring in streams with fine gravel (free of silts and clays) and moderate flow rates, and overwinter in large, deep pools of streams—making connectivity between their seasonal habitats an important survival factor for this species. Their diet consists of insects, leeches, other fish and fish eggs.

Threats

Recent surveys, completed in 2012, of Athabasca Rainbow Trout populations show they are declining in at least 50 per cent of their range. Reproduction, and the resulting genetic mixing, with hatchery fish is one of the most serious threats to native Athabasca Rainbow Trout, as is competition for resources with non-native, stocked fish species. Habitat loss, degradation and fragmentation from industrial and agricultural pollution, climate change, and road development and resource extraction (coal, forestry, oil and gas) also threaten the Athabasca Rainbow Trout.

Further Information

This species was listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in May 2014. If listed under the Species at Risk Act (SARA), a recovery strategy and an action plan will be developed to prevent the loss of this species in Canada.

For more information on how species at risk are protected under the Act, visit the Species at Risk (SARA) Public Registry Profile.

Rainbow Trout (Athabasca River populations)

Photo of a Rainbow Trout

Adult Athabasca Rainbow Trout (Photo credit: Ward Hughson, Parks Canada)

Scientific Name: Oncorhynchus mykiss
SARA Status: No Status
COSEWIC Status: Endangered May 2014
Region: Alberta

Distribution of the Athabasca Rainbow Trout from COSEWIC 2014).

Distribution of the Athabasca Rainbow Trout from COSEWIC 2014).

Did You Know?

Rainbow Trout are native to northeastern Siberia and western North America, from Mexico up to Alaska, but it is also a popular sport and food fish in general. As a result, this species is commonly raised in hatcheries and is now stocked in many waterbodies across the world. Athabasca Rainbow Trout are one of the few remaining native Rainbow Trout still found in North America, east of the continental divide.

Athabasca Rainbow Trout are also an important resource, historically and currently, for Indigenous Peoples of the area. They have also been the subject of many important genetic, evolutionary and biogeographical studies, some of which shed new light on how animals came back to watersheds east of the continental divide after the last ice age.

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