Stream Fishing for Lake Trout by Boots Allen
An Unconsidered Realm:
Wyoming’s Snake River is known as native cutthroat country. The watershed, consisting of dozens of tributaries, spring creeks, and lakes, is considered one of the strongest native fisheries in the United States.
Lesser known is the fact that the drainage also holds small, but stable, populations of other species. Brook trout and grayling can be found in several high country lakes and creeks. Brown trout populate the upper Snake in strong enough numbers that anglers are not necessarily surprised to hook a couple in a day’s outing. And Kokanee salmon make late summer runs up select streams feeding Palisades Reservoir.
All of these fish add a bit of diversity for fly fishers looking for something a little different from waters dominated by Snake River fine-spotted cutthroat. But without question, the strongest population of non-native trout within the watershed is the lake trout, or lakers.
Often referred to as mackinaw, lake trout in this part of the Rocky Mountain West have gained a strong following amongst local and visiting fly fishers. Perhaps the more popular is Jackson Lake. It is the largest body of stillwater in Wyoming’s Snake River drainage.
The Snake River, which flows into the lake upstream from Yellowstone National Park, leaves it via Jackson Lake Dam. The dam acts as a conduit whereby mackinaw can access the Snake River downstream. The spillway and tailwater below the dam are one of those few places in the world of fly fishing where lakers can be targeted on a trout stream. As with those anglers who cast to mackinaw on area lakes, this little fishery has developed a small but dedicated cult following.
Enter the Lake Trout
Lake trout were first introduced to the Snake River drainage in the 1890s when the federal government stocked them in previously fishless Lewis and Shoshone lakes. There is evidence that lake trout migrated downstream to Jackson Lake by the early 1900s. Mackinaw were firmly established in the lake by the 1930s when the Wyoming Department of Game and Fish (WDGF) began supplementing the population. These stockings—numbering anywhere from a low of 17,000 to over 300,000 annually—continued until 2006.
100 years later, Jackson Lake has developed into a thriving sport fishing venue attracting thousands of anglers a year. Trophy lake trout are the featured species. In fact, the Wyoming state record mackinaw – 53lbs – was caught in the reservoir. While several lakes in Yellowstone and Grand Teton National parks contain strong populations, none of them have the drawing power of Jackson Lake.
Despite the stocking of hundreds of thousands of rainbows, browns, and brook trout over the years, few invasive species have gained even a toehold on the Snake River itself or its tributaries. Non-native trout make up less that 1% of the total abundance on the stream and its tributaries. Fine-spotted cutthroat rule the watershed.
But the five mile reach below Jackson Lake is different. Where much of the river and its tributaries average over 16 feet/mile, this tailwater section pitches at only around 4 feet/mile. Parts of it even feel devoid of current, much like a lake. It seems conducive to the survival of almost any species of trout. Here, browns can be caught with much more frequency. So, too, can lake trout. Flows from the dam can be anywhere from 350cfs during the winter months to over 7,000cfs in early summer. Regardless of the flows, lakers are caught year round.
Fishing for Lakers on a Trout Stream
The low gradient, uniform stream bottom, and relatively small cobble size all combine to make this portion of the Snake ideal for wading. It is by far the most popular way to fish this tailwater reach. Nonetheless, watercraft are often employed and can provide advantages not offered through wade fishing.
Lake trout are found in their highest numbers within the first half mile immediately below the spillway where they reside alongside cutthroats, browns, and whitefish. It is possible to fish this portion of the river and catch as many or more mackinaw than other species present. Their abundance gradually decreases with each passing mile downstream. Lake trout present, but they are caught with noticeably less frequency. Five miles below Jackson Lake Dam, Pacific Creek enters the Snake as its first major tributary. Stream gradient increases significantly and intensifies further downstream. Lakers, as well as every other species of trout other than cutthroat, become almost non-existent.
Streamers are an obvious choice for lake trout fly fishers. I tend to use the same patterns I employ on area stillwater – moderately sized baitfish imitations like Rickard’s Seal Bugger, Chicklets, Clouser Minnows (sparsely dressed), Booty Call Minnows, and Mohair Leeches. My line choice and retrieval rate and tempo varies with the water I am fishing. Most water where I find lake trout have a considerable amount of depth compared to the rest of the stream. As such, I rely on slow sinking lines (hover and intermediate). At times, six- to eight- feet of T-8 or T-11 can come in handy. Retrieval speeds are generally slow to moderate and produce the best results, regardless of the line you employ. Speeding up the retrieve is something I generally do only when slower strips are not producing.
While streamers are a go-to choice, even better results can come from aquatic invertebrate imitations. Much of what exists in the lake is also available to trout on the Snake tailwater reach. Mysis shrimp and scuds get washed out of the lake with increased releases frequently. I have caught lake trout, cutthroats, and brown trout with several shrimp and scuds visibly lodged in their throats as I removed hooks. Chironomid larva and pupa imitations are also good choices. My favorite include simple patterns like Zebra Midges and more intricate flies like Day-2 Midge Pupa. These bugs are not just about winter. They will work year round.
More stream-oriented bugs like grey drakes, caddis, PMDs, and yellow sallies populate this part of the Snake. Grey drakes tend to emerge in early summer (June into early July). I will perform slow pinch retrieves to imitate the movement of these swimming nymphs in eddies and seams. Caddis, yellow sallies, and PMDs will emerge in late June and early July and can be counted on well into August.
The Survivability Factor
Like all fish, lake trout have evolved to survive in environments with specific requirements. They are not cut out for streams. The simple fact of the matter is that lakers on the Snake River do not live too long. WDGF lake trout specialist Diana Miller pegs the maximum duration of survival at around one year. This is readily evident to the angler. Recent arrivals tend to show a certain amount of health and plumpness. Those that have been in the river for several months will retain their length, but will also be noticeably slender.
This is as good reason as any to harvest lakers caught on the Snake. They just won’t last too long out there. Not to mention they are competing with native cutthroat, which is the most important species in the watershed, if not the entire Rocky Mountain West.
- written by Boots Allen