Every fisherperson has their “honey hole”, but have you ever noticed that sometimes it is sweeter than others? To be able to effectively target trout year-round, an angler must be able to predict where trout will be (and what they will be eating) on any given day of the year. An understanding of the life history of different trout species is a great way to inform your search for new fishing spots.
I have spent the last 3 years of my life studying aquatic biology and fisheries
management at the University of Montana in Missoula. This discipline was an easy choice for me, as I have been an avid fisherman since I was knee-high to a
grasshopper, and moving to the Rocky Mountains was always a dream of mine. From my studies, it has become clear that most trout do not stay in one place for their entire lives; they look for ideal water temperatures, maximum food availability, and a suitable spawning habitat— all factors that change with the seasons. Doing your research on the species of fish you're after, their habitat, and their migration patterns, ensures that you're casting over fish consistently— getting them to eat, then, is up to you.
Brown Trout & char (Salmo truta & Salvelinus)
Brownies and char species— like brook trout, dolly varden, and arctic char— all spawn in the fall, which makes their migration timing and behavior similar. In general, brown trout spawn after the char species, usually further downstream, sometimes even in side channels in the lower rivers.
Browns spawn in late fall (October-December) and lay their eggs in redds (nests of gravel that are constructed and protected by female brown trout) in the shallow
reaches of tributaries, headwaters, or side channels that feed a larger river. During the winter, you can find browns in their overwintering habitats, which is downstream, but very close to their spawning sites and in deep pools. The winter is generally a time of low productivity both in trout’s growth and feeding because aquatic nymphs are deep within the substrate and largely not available to be eaten by trout. However, during the winter, a hungry brown trout will seize an easy meal. To catch a brown trout during the winter, try large beaded nymphs and san juan worms with plenty of weight under an indicator in slow deep holes.
Spring: The spring is initiated by longer days, warmer temps, and higher flows. These conditions signal brown trout to begin the hunt for food, and they will generally flush further downstream while feeding heavily on the aquatic nymphs—which are dislodged from the substrate. During the springtime, try throwing bright streamers in high dirty water and large stonefly nymphs in mid river reaches.
Because the conditions allow for good dry fly fishing throughout the day— and even good night time fishing— the summer is arguably the best time of the year to catch brown trout. During the summer, brown trout will be in the mainstem of the rivers and located around areas of high food densities. While fishing, look for places that provide shade or cover since brown trout are very territorial and rely on shade to stay cool and protected from predators. Throw whatever’s hatching and get your dry fly fix in while it lasts. And don't stop at sundown— some of the largest browns are caught in the middle of the night during the summers using mouse or frog flies.
The onset of fall is one of my favorite times to target brown trout because they
become even more aggressive than other times of year. They are about to make their migration to their spawning grounds and they are looking to kill anything in their path. To intersect the large aggressive pre-spawn brown trout from the end of September through October, fish the mouths of tributaries, or further upstream in the mainstem with streamers. Once the browns are in full spawning mode, you will have a hard time making one eat, even though you may see them. This is a good time to target the rainbow trout that are likely lying in the pools directly downstream of the browns, eating the eggs that drift down stream.
Bows and Cutties (Oncorhynchus)
Unlike brown trout, rainbows and cutties are the farthest away spatially and
temporally from their spawning sites during the winter months. During this time,
anglers should look for deep holes with low flows in mid to lower river. Some of the most productive winter trout holes are places where relatively warm water is added to the stream. These places include features like hypolimnetic release dams (tailwaters), ground water influx, the confluence with a spring creek, or even
anthropogenic structures like waste water treatment plant outflow pipes. On clear
days, Shallow sloughs and backwaters will warm up from the sun and lack of leaves and cause midge hatches in mid-winter. These conditions are extremely technical to fish, but pose a fun (and cold) challenge.
Oncorhynchus trout (the rainbow and cutthroat trout) spawn in the spring, however their spawning habits differ slightly: rainbows spawn pre-runoff, and cutthroats spawn post-runoff. During the end of winter and early spring, a large proportion of these species’ populations will make fairly substantial migrations between their overwintering habitat and their spawning sites upstream. If you can intercept this migration, you will likely have a sore arm by the end of the day. Throw pink and red nymphs, worms and even small streams to trigger the aggressive nature of these pre-spawn trout. Make sure for follow your local regulations to avoid fishing closed creeks or tributaries.
It is likely that if you are reading this, you already have an idea where to catch trout in the summer. Still, some good things to try and look for are cool water, river
complexity, and bug activity. Rainbows will flush further downstream through the
summer and cutties will often stay further upstream where there is colder water. As water temperatures approach optimum growing conditions for rainbow trout (12-18 Celsius), you will find that they expand their holding habit to maximize their feeding opportunities— look for fish in riffles where the aquatic macroinvertebrate densities are highest.
As the days get shorter and colder, the rainbows can do one of two things: either they can follow other spawning fish to feed on their eggs, or they will head toward their overwintering habitat. If there are not a lot of browns, brooks, or whitefish in your system, then forgo the first option and target rainbows in deep, slow holding water around mid to lower river. Some of the best dry fly fishing for rainbows around where I live in Montana happens in the fall— the mahogany dun hatch is thick on the lower stretches of rivers and there is a fraction of the anglers out on the water. If the bugs aren’t out, nymphs will always grab the attention of a trout heading into a long cold winter.
For me, the search for trout is an endless endeavor and studying their biology and ecology has helped me find my own (seasonally specific) “honey holes”. I find the deeper down the metaphysical fly-fishing worm-hole you go, the more it rewards you — don’t be afraid to try new places, flies, or techniques and eventually you will stumble onto the sweetest of “honey holes”.