The Yellowstone River begins as a tributary to Yellowstone Lake, southwest of the Absaroka mountain range in Yellowstone National Park. Upon leaving Yellowstone Lake, the river joins the Missouri River to form the longest contiguous river system in the United Sates.

Yellowstone Lake and Yellowstone River are the home of Yellowstone cutthroat trout, the indigenous species. Unfortunately, lake trout were introduced in 1994, and raised havoc with the cutthroat population, until eradication programs began in 2008. (Click here to read “The Yellowstone Lake cutthroat trout recovery story,” in the May 19, 2021 River Reporter.)

In 2020, the National Park Service used gillnets to remove 326,000 lake trout. In addition, 33,000 pounds of a soybean derivative were deposited on lake trout redds. (Redds are what biologists call spawning beds.) That material suffocates lake trout eggs.

As a result of the gillnetting and treatment to the redds, the National Park Service reported that the lake trout population had been reduced by 79 percent, which is good news for the cutthroat population, the predators that feed on those trout and certainly for us, who fish for the species.

Cutthroat trout spawn from April to July. Unlike most trout spawning runs, where fish move upriver, Yellowstone cutthroats migrate from Yellowstone Lake downstream into the river. When cutthroat populations are up, anglers and tourists alike can stop on the Fishing Bridge, gaze into the river, and see cutthroats holding in the current or on the move to their spawning grounds.  

I had the opportunity to fish the Yellowstone River in September 2001 and during that same month a year later. We stayed in West Yellowstone, MT, which was about a 45-minute drive to the Yellowstone River, depending on how many buffalo were sleeping in the road.

At that time, lake trout predation on cutthroats had not been an issue to the degree that their population was impacted and the fishing affected. The trips we made in 2001 were very productive. We fished a reach of river called the Estuary. The Yellowstone in the park is a very large river, with summer flows over one thousand cubic feet per second (cfs). Not an easy river to wade. While my friends were able to cross near the tail of the Estuary, I stayed on the roadside.

That first year, we fished the Estuary beginning in late afternoon, casting until dusk. There were some medium-sized dun-colored mayflies hatching, with a fair number of cutthroats rising to those flies. I had feeding fish rising all around me, most likely because I was quite a way from shore. Cutthroats, like their remotely related cousins, the eastern brook trout, are not particularly difficult to catch. Pretty much any well-placed fly will bring a swirling rise and hooked trout. All of the cutthroats we landed were large, post-spawn adults. Size ranged from 18 inches to 24 inches. There were no small cutthroats taken. My largest was a 24-inch male, in bright post-spawning colors.

Sometime during the last week of our stay in West Yellowstone, we went back to the Yellowstone River. On that trip, which was during the afternoon, there were no flies hatching and as a result, no surface activity. I remedied that situation by drifting a pair of prince nymphs across and downstream, with about 30 feet of fly line. Using that method, I was able to get my flies down in the water column and hook a few nice cutthroats.

We returned to the West Yellowstone area again in the fall of 2002. During that trip, we fished the Yellowstone on only one occasion. As in the past year, we fished the same area, the Estuary. We arrived late in the afternoon to find the river quiet, with no surface activity. So my two friends decided to go to Yellowstone Lodge for dinner. I brought a sandwich and decided to stay and watch the river. Downstream, a herd of about 100 buffalo crossed. Just as the sun began its final descent toward the west, a few spinners began to appear over the river, lay eggs, and die. As the spent flies fell to the river, cutthroats began to rise. I waded out, made a few false casts and immediately hooked and landed a nice trout.

If I remember correctly, I rose two or three more cutthroats before my friends returned. Because darkness was only about an hour off, we decided to head back to West Yellowstone and take advantage of the remaining light. With buffalo, elk, and other critters wandering the roads, Yellowstone Park is not a good place to be traveling after dark.

Fishing the Yellowstone River in Yellowstone Park is a unique and eerie experience. The park is a remote and wild place, violated only by a few roads and structures, remaining mostly undisturbed by the hand of man. The Yellowstone River cutthroat population has recovered nicely, thanks to efforts by the National Park Service to remove lake trout from Yellowstone Lake. So if you are in the Yellowstone area, make sure to plan a trip into the park to fish for these beautiful, native trout. Just keep in mind that you will be in grizzly country, the population is up, and bear spray is probably not a very good deterrent.