I love fly fishing for many reasons. One of those reasons is the opportunity to observe the relationships between predators and prey. When I’m trout fishing, there is no better sense of accomplishment than having a weary trout rise to the surface for a delicately presented dry fly. On the other end of the spectrum, nothing gets my stoke levels going like a bloodthirsty trout inhaling a large streamer. If only there was a way to combine the murderous aggression with the jaw-dropping visuals and the elusiveness of the strike. Well, as it turns out, there is a great way to combine those factors into a Frankenstein of epicness (wow, what a coincidence)! Using mouse patterns for trout, or “mousing” is my favorite, occasionally effective, always exiting way of targeting trout on a fly.
Why would a trout eat a mouse?
As trout grow bigger, they need more and more calories to maintain their size and continue growing, just like humans. Also, like humans, trout expend calories when they move around, like when they feed. They’ve figured out that to have the most efficient growth, they need to take in a lot more calories than they use. So bigger trout tend to eat larger meals, less often. This is the same principle that makes throwing large streamers effective for giants. Although mice do not often fall into rivers, trout know they pack a lot of calories, so an opportunistic fish will take the chance. Most trout, being wary by nature, will ignore a passing mouse, but that is irrelevant because when you are mousing, you aren’t searching for most trout, you are on a quest to find that one special fish.
The gear you use for mousing is purely situational. When I’m mousing in a small stream for native Brook Trout, I will use my 3wt, but when I’m in Alaska, I use a 7wt religiously. When it comes to rods, just use the same rod that you would normally use on the river you plan to mouse. The only constant in mousing gear is fly lines. Clearly, since mousing is a surface game, only use floating lines. When it comes to fly choice, there are many different options. For trout, I prefer patterns that ride lower in the water. My favorite mice are the Mr. Hankey, the Morrish Mouse, and the Master Splinter.
When fishing a mouse, you want to imitate what would happen is a mouse finds itself in the unfortunate situation of swimming. Cast downstream at a 45° angle, and get your fly as close to the bank as possible (because mice cant fly). Once the fly splats down, raise your rod and wiggle the tip, and let your fly swing down and across. The raise of the rod and the wiggle of the tip makes the mouse “skate” or move in a way similar to how a mouse would swim. Repeat this until the stars align, and then give it the old fashioned trout set (sorry to literally every saltwater guide ever).
Successful mousing requires specific breed of anglers, but if anything you just read got you excited, give it a try, you never know what lurks in the shadows!