Once common in North America, the westslope cutthroat is declining across its range.

In Banff National Park, westslope cutthroat are found in streams flowing into the Bow River. Many of these fish are hybrids due to cross breeding with introduced rainbow trout. We no longer stock non-native fish in Banff, but their genes live on in the DNA of wild fish. Fortunately, some isolated streams in the park still have pure populations of native cutthroat trout.

We are working to keep both our fish and our streams wild.


Note to anglers: there is a zero possession limit for westslope cutthroat trout in Banff National Park.
Fishing Regulations Summary (PDF 787 KB)


Why is westslope cutthroat trout in danger?

Across its range, westslope cutthroat trout is threatened by:

  • displacement and hybridization with non-native fish
  • loss and damage to stream habitat
  • increasing water temperatures due to climate change

Genetic invaders

So the rainbows mix it up with the cutthroats – what’s the problem? This interbreeding dilutes the wild gene pool. This makes Westslope Cutthroat less able to adapt to change and survive over the long run.

What are we doing to help this species?

We are helping to conserve and restore westslope cutthroat trout in Banff National Park by:

  • conducting stream surveys to locate westslope cutthroat trout in the park
  • collecting DNA from cutthroat trout to find out if they are hybrids or wild stock
  • restoring fish passage by fixing and replacing highway culverts

Learn more

Species at Risk Public Registry – Species profile: Westslope Cutthroat Trout, Pacific populations