Southeastern Minnesota contains one of the greatest concentrations of limestone spring creeks in the world and lies in a unique geologic region known as the Driftless Area. The region’s peculiar terrain is the result of its having escaped glaciation in the last glacial period. This unglaciated (no glacial deposits or “drift”) region is comprised of limestone bluffs, cave systems, blind valleys, springs, and hundreds of miles of cold streams.
This highly oxygenated spring fed stream water creates a superb environment for trout. Vegetation thrives on the alkaline nutrients in the water thus providing a habitat in which aquatic invertebrate insects thrive supplying an ample food source. In all reality however, even on great trout streams, fishable hatches are not occurring most of the time, this is especially true during the summer. Terrestrials, on the other hand, carelessly make their way into streams throughout most of the prime fly-angling season. While grasshoppers are usually associated with late summer and early fall, ants and beetles are active earlier. Terrestrials are often effective during difficult hatches, when even a precisely presented imitation won’t seal the deal. Trout will often “strike” on an ant or beetle after purposefully refusing the more accurate dry fly pattern you’ve offered. Perhaps this is due to the perceived reward of a higher protein meal.
When the prolific spring / early summer aquatic insect hatches of Mayflies and caddis have waned the land-based insects will begin to become a primary target of hungry trout. During late summer and early fall, trout seem to become less selective when eating on the surface and will key in on a wide array of terrestrials, from tiny black ants and beetles to crickets and grasshoppers.
Now that your fly box arsenal is complete with the necessary terrestrial weapons, it’s time to put them to use. Trout do tend to key in and feed on the most available food supply, and anglers should pay attention to that fact. If you’re on the water and ants are constantly falling off the overhanging trees, you probably should consider fishing ants. If on your walk in to fish your favorite stream you encounter grasshoppers bouncing off your waders, it may be a wise choice to throw a Hopper pattern. Use the power of observation when you’re fly fishing and select your flies accordingly.
Be mindful of the weather as warmth plays a major role in the arrival of terrestrials whereas wind creates an ideal situation to target trout with mimicking fly patterns. Be aware of these conditions and plan your time on the water accordingly. Consistent warm weather is a major factor in the emergence of land-based insects. They are cold-blooded creatures, high temperatures mean their metabolism runs faster, they become very active, eat more and grow faster. Not many anglers appreciate a windy day in summer, but these conditions in actuality often provide the best scenario for terrestrial fly fishing on the streams of the Minnesota Driftless area. The breeze dislodges insects from nearby grass, trees and foliage where they end up helpless in the water.
Search out flat or slower moving water in the early stages of the “terrestrial season”. You’ll have much more success in coaxing trout to rise to the surface if you focus on fishing slow moving pools, long runs and eddy areas. When the terrestrial season kicks into full gear, you can then start fishing fast water too. Stick to ants, beetles and crickets early on, as grasshoppers don’t find their way in front of trout in numbers until farther into the summer months.
Experiment with different size terrestrials. Sometimes the bigger profile, and added food value it provides, will persuade a trout to eat when a small pattern won’t. I generally start big at first, but if I’m getting refusals, I’ll always downsize my pattern. You don’t need a multitude of different terrestrial patterns but having different sizes is the key. Fishing terrestrial patterns is no different then fishing any other trout flies. If you aren’t having luck, you probably need to change your pattern.
Experiment with presentation. Cast towards the bank, twitch then dead-drift – repeat the cycle. Adding an occasional twitch can be effective, but don’t overdo it as you run the risk of putting fish down. As with any other fly angling, be stealthy. One of the most overlooked techniques of being a successful fly angler is the ability to stalk or employ methods of stealth while fishing. A shadow, movement, or sound can easily spook fish. The ability to employ stealth can be advantageous to the angler searching out the incredibly wary trout in the crystal clear spring-fed stream waters of the Minnesota Driftless. Fly fishing with terrestrial patterns on the limestone spring creeks of this area has great appeal to the fly angler who values high quality streams, exciting fishing and beautiful surroundings – come see for yourself!
Here is a look at some of the important terrestrial fly patterns for fly fishing in Southeastern Minnesota:
Dave’s Hopper: A great, classic dry fly that imitates a grasshopper and gets big strikes from trout. Cast this dry fly along the banks during the height of summer for the best action.
Morrish Hopper: This is one of the best, simple, productive, buggy, and easy to fish hopper patterns out there. No floatant is required on this all foam creation. You can “twitch” it on the surface better than many similar patterns because of the rubbery, flexible legs.
Black Transpar-Ant: The Transpar-Ant is a weighted fly and is fished subsurface. During the summer days with high wind or big rain, ants in great numbers get washed or blown into streams and drown. Try “nymphing” with these and watch your catch rates increase.
Foam Beetles: A very simple, buggy looking foam terrestrial. The foam body keeps it on top of the water without a lot of effort. This is a continual top producer during the summer months as trout love to eat beetles that are blown into the water.
Crickets: This particular cricket fly pattern is tied just like a Dave’s hopper but all black. These are best fished after a significant rainfall as they often get washed into streams by run-off. Fish these in a dead drift and add “twitches” in seams along banks and in areas of transitional water.