September is here and fall is just around the corner. Check out our recent blog on Five Rivers to Fish This Fall. All of our rivers are not in great shape to finish out the season--which will last into November!
For fishing in southwest Montana right now terrestrials have been thick on our local waters. Hatches of caddis have been mostly limited to the early morning and late evening hours of the day, with the main exception being black caddis on the Upper Madison which has been lasting a little more into the late morning hours. PMDs have laid to rest but tricos are still hatching on our tailwater rivers like the Upper Madison and Missouri Rivers. Early mornings and into the afternoons are still the best window of fishing action. Late evenings can also fish well, but it is also ok to hit a local bar or restaurant and fish again in the early morning.
We expect the terrestrial fishing--hoppers, ants, and beetles--to hang in there for the next few weeks and last till October. Our cold and wet spring means there are ample grasses which means there are also plenty of grasshoppers. We are optimistic of another very and are excited for some twitching hoppers.
Overview
This time of year it is crucial to pay close attention to the insects on the water at a given time, often PMD’s hatch before yellows sallies for example. On highly fertile fisheries with thick hatches like spring creeks and tailwaters the trout become very selective during the hatch and you must imitate the correct species as well as life cycle of the insect that the trout are keying in on. On less fertile freestone streams it is more of a potluck and the trout will feed more opportunistically. On spring creeks plan on match the hatch but if you are fishing waters with sporadic hatches try big attractor dry flies on top or large streamers down under to move fish farther than smaller patterns. Expect to fishing to slow down abruptly once the insects are gone but you can often continue to pick fish up later in the day. In the evenings there is often another flurry of activity just before dark.
Hatches
Hatches of stoneflies and PMDs are less frequent than earlier in the summer. Even though aquatic insects are by far the dominate food source right now on most streams and rivers, trout are still opportunists and they often will feed on the most abundant food source. Make sure to have all stages of the life cycles in your boxes. For mayfly species like the pale morning dun have nymphs, emergers, cripples, duns and spinners. For caddis have larva, pupae and adults. For stoneflies nymphs and adults. Expect to see pale morning duns (small size 14 yellow and light grey mayflies), yellow sally stoneflies (size 14-12 yellow), caddis (several species, tan and cream size 16-10 – fast active fliers), golden stoneflies (big size 8 with dark gold body) and even some late salmonflies (giant size 2, three inches long). There are also some different drake species of large mayflies hatching that can excite fish such as brown and eventually green drakes.
Fly selection
You basically have to determine if you are going to match the hatch or bust the hatch this time of year. When you can see fish actively rising on the surface it is generally best to match the hatch. The same as true before a hatch, nymphing with the imitation of the nymph or emerger that the fish will see later is a good bet. When the hatch starts if fish are on the surface it is best to match the hatch or try a “cripple” or “emerger” pattern behind an adult imitation. If the hatch gets to a blanket stage then try a size or two larger than the natural. If fish are not taking flies off the surface then the nymphing game can be tougher during the peak of the hatch unless you are sight casting. There can be so many naturals underwater that your imitation has beat the odds that are often 100:1 with so many real bugs in the water. If you are nymphing during a strong hatch it is often better to switch to much larger patterns or streamers dead drifted or stripped rather than compete with naturals.
Interestingly when a hatch is sparse we flip flop are strategy. On the surface you can still catch fish with an exact imitation but you can often be even more successful with a large attractor fly that will move fish farther. The trout aren’t so keyed in on the natural that they won’t switch gears and eat something even bigger like a fat albert or chubby Chernobyl. When nymphing it is nice to continue to have an exact imitation but consider trailing it behind something larger like a big stonefly nymph, crayfish or sculpin.
Reading water
Flows are all over the place right now on different rivers. On fisheries that have already dropped significantly trout are already moving into deeper runs for protection but on the rivers with higher flows they are in the safe havens that have slower current speeds like along banks, behind rocks and on the inside corners of bends or slower tail-outs.