Eastern Oregon Gold: Oregon’s Isolated Population of Native Westslope Cutthroat Trout

If someone told you that Oregon had three native species of cutthroat trout you may be surprised. Many people are only familiar with Oregon’s Coastal Cutthroat trout. These fish can be subdivided into two populations: resident fish that never leave their natal streams/drainages, and sea-run fish that have an anadromous life story much like a salmon and steelhead spending some time in the ocean feeding and growing. Eastern Oregon also has a small population of Lahontan Cutthroat Trout, just like the brutes in Pyramid lake. The third Cutthroat is one that is famous here in the West, but generally Oregon doesn’t come to mind when this fish is mentioned. The Westslope Cutthroat trout, once widely regarded as the most abundant Cutthroat in the West, is isolated to a small portion of a drainage in Eastern Oregon.

Nick stealthily reaches around a corner on a spring fed creek containing John Day Westslope Cutthroat Trout

The Oregon Westslope Cutthroat is a isolated to the upper reaches of the John Day Basin. It is not entirely clear how these fish got here, but one theory states that they could have been isolated/deposited by the Missoula floods. The same holds true for the population in the Yakima basin North of us in Washington which is totally isolated in a similar fashion. Our Westslopes share the upper basin with native Columbia Basin Redband Trout, Bull Trout, as well as non-native invasive Brook Trout. The John Day Westslope Cutthroat trout has a caramel/olive colored appearance. Spotting on the fish is largely concentrated towards the rear of the body, and the belly is generally devoid of spots. They have the telltale Cutthroat scarlet colored “slash” under their gills. They can occasionally feature a rosy colored belly and cheeks as well.

The Oregon Westslope Cutthroat generally do not get as large as their “out of state” cousins.

Much of the middle and lower John Day get far too warm to sustain trout populations, and it is best known as a smallmouth fishery. The Westslopes are found in the upper portion of the basin, especially spring fed tributaries. Fish will move through the system and overwinter lower down. They can be especially difficult to find in the lower months because the floor of the basin is largely privately owned for grazing, residences, farming, etc. In the summer months, these fish can be found in the headwaters and tributaries where they can find shade and cold water in closer proximity to springheads.

Here you can see the scarlet telltale Cutthroat “Slash” on the underside of the jaw.

Nick and I ventured out to catch these fish some weeks ago. It was a trip I have done several years before, but was new for him. I had done my research along with a friend and we went in with a list of tributaries that should hold these fish. That first trip was filled with mapping to several dry creek beds and lots of driving. Towards the end of the trip we had found them, so I had a rough idea of where to go. This time I was more excited to explore some other tributaries in the area.

A meandering spring creek lazily bounces back and forth creating deep holds for the fish along its banks.

These fish live primarily in spring fed tributaries at the top of the John Day basin. You will find everything from rolling meadows with undercut banks to tight brushy forest with lots of shade. Generally the gradient is low, so the stream meanders slowly back and forth creating deeper sections in the corners of the creek. Parts of the upper drainage might look “messy” and difficult to fish, but the logs, stumps, and other debris in the river provides great habitat for these fish.

Water like this is hard to fish, but provides great habitat for trout of all ages, as well as shelter from predators and anglers alike.

Generally in my experience, as you work your way up first you will bump into native Columbia Basin Redband Trout. These fish live alongside the Westslopes and naturally, there is some hybridization. Eventually you will bump into some Cutbows, and if you keep moving higher you will find the more pure looking Westslopes. This is largely dependent on the portion of the river or what tributary you are in. In my experience, I found the Westslopes in the cooler water with deeper undercut banks and what looked to be better habitat suited for growing larger fish. There would be some intermingled small Redbands in this section, but by the size of the Westslopes, it seems like they generally outcompete the Redbands given the right habitat.

The heavy spotting, red lateral line, and unspotted tail are ways to differentiate Columbia Basin Redbands from Westslopes. If you were to flip this fish, it likely would not have had a slash under its jaw.

Because it is generally easier to find these fish in the warmer months, water temperature is something that you should be mindful of. Carrying a thermometer is a must when pursuing these sensitive fish. Much of the system is spring fed in the upper reaches, but you should still be cognizant. The day Nick and I fished it was 98 degrees out, but the water we isolated our fishing to hovered around 56 and never broke 60. The warmer sections that got more light, were shallower, or lower in the system were devoid of trout. If they were in those portions, they definitely didn’t want to eat; if they did, we would risk harming a vulnerable fish population.

Keeping these fish wet when observing them is one way to keep them safe. Also carrying a thermometer can help you reduce harm to these fish.

The cold water in the upper stretches of the drainage is prime habitat for native Bull Trout. You may see these fish, and even have one come after a fly. We urge you to leave these fish alone because their population is even more at risk than their Westslope and Redband neighbors that they share the creek with. The system is unsuitable in the lower stretches, so adult Bull Trout do not have space to migrate as they’d like to. Another concerning threat to the native Bulls is the presence of Brook Trout in the system. They both are members of the Char family, meaning they can hybridize. This generally creates sterile offspring and reduces the amount of spawning adults. Brook Trout in the West, when present, generally overpopulate a stream and have a high density of small adults in the system. This creates an issue of food competition and ravenous brook trout eating native fry. When fishing delicate systems like this if you want to take a fish, make it a brook trout. That way you get a small meal and can help the overall health of the stream. See the figure below of how to discern native Bull Trout from invasive Brook Trout; to an untrained eye, they can look similar. If you do happen to catch a native Bull Trout please keep it wet, handle it as little as you can, and reflect on the special fish that you just caught upon releasing it. If you can’t properly ID it remember: “If you don’t know, let it go”.

If you don’t know, let it go.

Any rod from a 2wt to a 5wt is sufficient to catch these fish. I was using an 8’6 3wt Winston Air 2 and Nick used a 9″ 4wt G. Loomis IMX Pro v2. A standard floating line is ample to fish the streams in the area, we both fished a Scientific Anglers Amplitude Infinity Textured Line, a shop favorite. Nick and I primarily had all of our action on dries, but had a few fish take a small lightly weighted dropper below a bushier dry. Terrestrial insects such as grasshoppers, crickets, ants, beetles, etc. make up the bulk of these fishes diet in the summer. I had better luck getting fish to eat using 5x to my dry and my trailing nymph would be off 6x tippet. Here are some dries that worked great for us: Mason’s Wingman Ant, Fat Angie, Dry Humper, Elk Hair Caddis Tan, or a Carlson’s Purple Haze. Here are some nymphs: Zebra Midge, Galloup’s Peacock Hares Ear #18, or a Juju Baetis. In the warmer months, there’s generally no need for waders. A good rubber coated small net, is important to have. A rubber coated net is especially important for these fish which need all the gentle handling that they can get. Lastly, a good thermometer is a crucial piece of equipment when chasing Oregon’s Westslopes.

Fish like these are keyed in to taking dries most of the summer.

These fish are part of a very sensitive population that are entirely isolated to the upper John Day Basin, meaning they have nowhere else to go. Several populations have depressed fish counts, so if you decide to pursue this special fish please use caution. Their largest threats include: warming waters, drought, grazing, farming, wildfires, human development, irrigation, and invasive Brook Trout. Several of the creeks I visited on my first trip years ago in a burn area were entirely dried up. Fish may have been higher in the system, but stressing those fish out even more is not something I wanted to do. Visiting the Upper John Day basin in search of Oregon’s only Westslopes is a special experience, and will give you respect for a resilient species in the face of all odds. Again, if you choose to pursue these fish in their home, please do it respectfully.

Pastures for grazing are not an uncommon sight when working your way up a tributary in search of colder water, and better habitat.

Nick’s thoughts on the trip: “The waters that these fish live in are part of such of a pristine ecosystem. It is amazing to be in their home and have the chance to catch these special trout in such a beautiful place. I would definitely recommend other people to get out there and track down some of Oregon’s unique trout species and have the opportunity to experience all of their different environments.”

Some of the smaller Westslopes are the most beautiful, still sporting their juvenile parr marks.

If you have any questions on the matter, please reach out to the shop, we are happy to help you out. Tracking down Oregon’s native trout will take you to some beautiful places, and give you an appreciation for the fish and places we are so lucky to have in our backyard.

-Simon

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1 Response to Eastern Oregon Gold: Oregon’s Isolated Population of Native Westslope Cutthroat Trout

  1. Miguel says:

    Hi Simon, a mystery explained. About 20 or so years ago, I was elk hunting on the ridge of mountains just north of Big Summit Prairie, on the north facing slope, in September, and hot. We were following a very small stream, often only 18 to 24 inches wide but cool water mostly protected from the sun. At one crossing I noticed a 4 or 5 inch trout with its head trapped between a piece of wood and a rock. It stood out due to the bright colors evidenced in your photos: very yellow with orange on the fins. It looked like a cutthroat but it was not in cutthroat territory. This small stream drained into Big Summit Prairie. It was part of the North Fork of the Crook River drainage but I suspect other than runoff season little water ended up flowing into the rest of the drainage. Les Schwab (I assume it was him since he owned it but could have been his predecessor) damned up Big Summit with several reserviors. This was pre-smart phones so no photos but my suspicion was that it may have been a planted brown (bright yellow) in a prairie reservior but your information indicates otherwise. My research at the time including talking to one ODFW biologist never hinted of resident West Slope Cutthroat.

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