Guest Blogger: Mike Cline, Bozeman, Montana

Rivaled only by the rainbow trout for the greatest number of distinct subspecies, the cutthroat trout of the American West provides the adventurous trout angler a unique challenge.  A challenge I must say that I’ve not yet tackled. But still with 14 recognized sub-species or strains, the cutthroat trout remains one of the great angling challenges in the American West.  I’ve been lucky enough to catch four of those subspecies but will likely never see them all. On the other hand, Cutthroat trout, Oncoryhnchus clarki make for great reading as well as angling.  Along with the rainbow trout, they are the “native” trout of the American West.  Surprisingly, the cutthroat trout was also the first North American trout described by Europeans.  In 1541, Spanish explorer Francisco de Coronado recorded seeing trout in the Pecos River near Santa Fe, New Mexico. These were most likely Rio Grande cutthroat trout (O. c. virginalis).  The Rio Grande cutthroat is the southern-most variety of cutthroat and has a stable but small foothold in the mountains around Santa Fe, New Mexico.  This is one I haven’t tried for yet.

The story of the cutthroat trout, or best I say its taxonomic history and life history is a complex one and difficult to sum up in any concise manner.  Of course, Robert Behnke’s books: Trout and Salmon of North America (2002) and About Trout (2007) paint the cutthroat story as good as any works out there, save one.  One of my favorite references on the cutthroat is Patrick Trotter’s Cutthroat Trout-Native Trout of the West (2008).  While Behnke’s seminal work on Trout and Salmon of North America devoted 347 pages to six species of Pacific and Atlantic Salmon as well as ten plus species of trout and other salmonids in North America, Trotter managed a whopping 548 pages on the cutthroat alone.

Although in the larger scheme of things, the cutthroat hasn’t received the literary attention that the rainbow, brook and brown trout have, the latest work dedicated to the cutthroat is one interesting read.  Greg French is a well-known Australian angler and writer who has fished around the world and is one of the most experienced anglers in Tasmania and New Zealand. In 2012, he and his wife visited Yellowstone National Park for several weeks of camping and fishing.  The result was The Imperiled Cutthroat—Tracing the Fate of Yellowstone’s Native Trout (2016).  It is a great read from two perspectives.  Greg really got into some of Yellowstone’s back country fishing for cutthroats and it was very interesting to listen to someone else talk about familiar places.  Most interesting however, was the different cultural perspective he brought with him. It was clear that at times he just didn’t understand why Americans do what they do.

I will probably never catch each of the 14 subspecies of cutthroat.  There’s a couple of reasonable possibilities—Greenback and Colorado River cutthroat aren’t difficult to find as are Bonneville and Lahontan.  Just a little travel and the right opportunity.  But for now, my experience is limited to westslope, coastal, Yellowstone and Snake River Fine-spotted sub-species.  These fish are prolific enough in the Northwest, Montana, Idaho and Wyoming to provides ample opportunity to tangle with one.

From a taxonomic standpoint, the reason there are 14 cutthroat subspecies is purely geographic and geologic.  From a common ancient Oncorhynchus species that migrated into fresh waters from the Pacific Ocean three to five million years ago, cutthroat trout populated lakes, rivers and streams as far east as Eastern Montana, Alberta, the Arkansas and Platt river watersheds in Colorado and the upper Rio Grande in New Mexico and Texas.  Once these watersheds became geographically isolated from each other and the Pacific Ocean through mega floods, volcanic activity and geologic upheavals, sub-speciation began in isolated populations. Ironically, the closest taxonomic and morphologic species to the cutthroat generated numerous sub-species through the same process but failed to achieve ranges east of the Rocky Mountains.  The rainbow trout and cutthroat trout are so closely related taxonomically that they naturally hybridize in the right environmental conditions.  Yet the historic native range of the rainbow did not extend east beyond the continental divide in the Rocky Mountains. On the other hand, cutthroats didn’t establish ranges on the western shore of the Pacific in Asia while the rainbow did.  The cutthroat populations that occur east of the Continental Divide have always challenged the curious. How did they get there? How did they migrate over the Rocky Mountains?

The four sub-species that established major native populations east of the divide are the Yellowstone cutthroat (Oncorhynchus clarki bouvieri), the westslope cutthroat (O. clarki lewisi), the Rio Grande cutthroat (O. clarki virginalis) and the greenback cutthroat (O. clarki stomias).  In each case, there is geologic and recent historic evidence that rivers that eventually flowed into the Pacific had substantial connections to rivers that flowed into the Gulf of Mexico at high mountain passes along the Continental Divide.  The most dramatic of these occurs in the remote Two Ocean Plateau area just south of Yellowstone National Park.  When Atlantic and Pacific Creek flows off a ridge in Absaroka Range it splits into two creeks—Pacific Creek flows west into the Pacific Ocean via the Columbia River and Atlantic Creek flows east into the Gulf of Mexico via the Missouri River system.  The place is aptly called “Parting of the Waters”. Fisheries biologists agreed that this pathway is how the population of Yellowstone Cutthroat was initially established east of the divide.  Similar watersheds existed in northern Montana for the westslope cutthroat, in Colorado the for greenback and New Mexico for the Rio Grande cutthroat.

The historic native ranges of all the cutthroat sub-species have shrunk significantly over the last century due to habitat loss, non-native introductions, hybridization and overfishing.  Two sub-species are considered extinct and others exhibit ranges at less than 5% or their historic native ranges. Yet the cutthroat trout remains a sought-after species for the fly angler.  In Yellowstone National Park and the Yellowstone river watershed, the Yellowstone cutthroat is still plentiful, despite predations by introduced lake trout, competition from introduced brown and rainbow trout, hybridization and heavy angling pressure throughout the watershed.  The same can be said for the Snake River Fine-Spotted in the Snake River watershed. The westslope cutthroat, although not that uncommon west of the divide, was essentially extirpated from most of its range east the divide due to rainbow and brown trout introductions into the Missouri River headwaters.  The westslope sub-species also suffers from hybridization with rainbow trout and there are estimates that the populations of genetically pure westslopes are extremely rare and limited to isolated populations at high altitudes.

For the angler however, the cutthroat is an exciting fly rod target.  They willingly take flies, especially dry flies when conditions are right.  The largest of cutthroat subspecies, the Lahontans in western Nevada routinely reach sizes exceeding twenty pounds.  Even the Yellowstone cutthroat trout can reach substantial sizes in lakes and large rivers like the Lamar and Slough Creek in Yellowstone. On the other hand, many of the sub-species in isolated populations are tiny, but colorful fish that are fun to take on tiny dry flies in remote places.

Even the anadromous coastal cutthroat sub-species which spends the great majority of its life cruising saltwater shorelines in estuarial waters along the northern Pacific coast is a unique angling challenge.

Unlike rainbows, browns and brook trout, the angler seeking to catch a cutthroat must come west to the Rocky Mountains, the Great Basin or the coastal ranges along the northern Pacific coast.  Although they have been raised in hatcheries and introduced into non-native locations, populations outside the mountain west have never been established. They are one of the great trout of North America and all the sub-species are certainly worthy adversaries.  They are the Disparate Pirates of the Rockies and Mountain West.


  1. I have always loved cutthroat trout–to me they represent high altitude wild places and the best and most memorable of the Great American West.

    Hearing or reading accounts like “cutthroats willingly take dry flies” (which I’ve heard before and have also observed) and other such behavioral generalities applied to one species as compared to another always gives me pause. By human observation, with perhaps a few small exceptions cutthroats have essentially the same life strategy as do rainbows in the same waters, and other than spawning months basically the same life strategy as do browns. And I believe life strategy (and how it is addressed) amounts to an exceptional way of “defining” any species.

    So…when we observe a noticeable cutthroat willingness to take dry flies as compared to other trout species, I find it worth asking myself how and why that might be so.

    I think it points to the fact that the menu of possible approaches to pursuing any given set of strategic life priorities can be many and varied…and that Nature’s “delivery mechanism” for a given strategic approach is a DNA signature. In this way a given approach to those priorities is injected into the great experiment called Life, to see how that approach fares. If it’s viable, that species (i.e. that DNA signature) survives; if it’s inspired, the species thrives. If the strategic approach is lacking or comes to be lacking down the road, the species either exhibits an ability to change its approach or else it flounders and eventually fails.

    To me these little observations such as “cutthroats willingly take dry flies” underscore the incredible spectrum of possible approaches that can spring up and be run as trials within the larger ongoing “experiment.”

    Nature is truly the most beautifully unconstrained game we can imagine; every nuance can make the difference…or can coexist with other nuances, each of which is tenable.

    – Mike

    1. Mike,

      I think the notion that “Cutthroat’s willingly take dry flies” is a common generalization that although it may be true in some cases, probably doesn’t have the support of any empirical evidence but I put it in there anyway. Most of the early writings about the Cutthroat came from encounters with the Yellowstone and westslope subspecies in SW Montana and Wyoming. These are arid environments with lots of terrestrials and prolific aquatic insect hatches. Early accounts of pioneers and soldiers fishing the Yellowstone and its tributaries told of catching buckets of grasshoppers and floating a live hopper on a piece of string down the river. Even today, when the cutthroat has to compete with rainbows and browns, a fat hopper pattern floated slowly down a seam will bring the slow deliberate rise of a cutthroat. When it comes to some of the other subspecies, its hard to tell whether the generalization holds true. In those cases where cutthroats live in marginally fertile waters—high mountain lakes and small streams–I suspect they behave like any trout does and grab anything that floats by on the surface or not. Additionally, I don’t know of any evidence that suggests sea run cutthroats take top water flies while in saltwater since they feed primarily on baitfish, crabs and worms.

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