Montana Rivers


What to Expect in October

Note: This What-To-Expect is from Westfly's Legacy pages and may not accurately reflect the current fishing at this venue.

Trout will be fattening up on blue-winged olives, mahogany duns, and October caddis in most of the state, and brown trout will attack streamers that are flung their way (well, maybe they will . . .). Fishing will start hot but will inexorably cool down as fall weather makes its entrance.

The ubiquitous blue-winged olives will be a major hatch on many rivers this month. Early in October they will hatch best on overcast days. As it gets cooler, they will hatch under most conditions. The nymphs will drift in the current throughout the hatch season, and you can take trout on nymph imitations, such as size 16-18 Pheasant Tails and gold-ribbed Hares Ears, from morning to dusk. Nymphs can be productive before, during, and after a hatch, and even when there is no hatch that day. The key is to make sure your imitation is drifting near the bottom. To achieve that goal, you may want to team your small nymph with a heavy fly, such as a Kaufmanns Stonefly or Pupatator.

During a hatch of blue-wings, Baetis Cripples and CDC Baetis are good emerger patterns. However, my hands-down favorite for a dun imitation is a Sparkle Dun; a Parachute Baetis works too, but I think the Sparkle Dun is superior. Rusty Spinners or Diving Baetis will take care of the final stage. Emergers, duns, and spinners tend to collect in backeddies and slow margins, and trout often just wait there for them to arrive.

Some streams will see two flavors of blue-winged olives: a size 18 version and a size 22 version. The latter is the tiny olive or TIFKAP (The Insect Formerly Known As Pseudocloen).

Mahogany duns are present on many rivers in the early part of the month. These mayflies migrate to slow water before emerging, and hatches usually take place in the slow margins of the river. Trout are in no hurry to sip the duns, and rises are usually lazy, head-and-tail affairs. Because the action is in quiet water, your approach and casts need to be stealthy. The best strategy is to wait until you see a rise, then cast to that trout. Blind casting usually just puts the fish down. Let your cast settle gently on the water and avoid lining the trout. You may need a downstream presentation. A red-brown size 14-16 Sparkle Dun works well; in a pinch, you can use a Parachute Adams.

October caddis are the big bug of the fall. They are often matched with a size 8 Stimulator, but the traditional orange pattern is a bit bright. Try a browner body and a darker wing. Another option is a Madam X tied with a brown-orange body and a dark wing; it floats with a low profile. Some anglers like to use an orange Turcks Tarantula.

Many anglers dead-drift a dry fly during this hatch and get no response. They conclude that trout don't take October caddis. Wrong. If your dead-drift generates no rises, try a little twitch. If that doesn't work, try a skating presentation. To skate the fly, cast down-and-across, throw in an upstream mend, then raise the rod tip and let the fly skitter across the surface. This can be deadly in riffles, just below riffles, and along current seams. Sometimes you'll have good success if you pull the fly underwater, then let it swing across just under the surface.

Terrestrials such as hoppers, beetles, and ants will be hard hit by the first major frosts. However, trout will take an imitation even if the big bugs are gone. Trout are creatures of habit and conditioning. Once they are used to eating an insect they will continue to look for it even when there are few of them left. It can take them a week or so to abandon the old hatch and switch to new hatches and foods.

Brown trout and big rainbows will be receptive to streamers this month, so carry a bunch of "big uglies" with you. Brown-and-yellow streamers are always popular with brown trout in the fall. Browns will also be eager for salmonfly and golden stonefly nymphs in waters where those bugs occur.

The first half of October can offer fine fishing in Montana. But sometime after the 15th you can expect some very cold weather, with morning temperatures into the teens. That will slow fishing considerably. So get out there early in the month--it won't last much longer.


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