Oregon

 

Rivers

Hatches divided by half-month.
 Super    Major    Minor    Slight    None

HATCH NYMPH/
LARVA
PUPA/
EMERGER
DUN/
ADULT
EGG-
LAYER
Ameletus
Blue-winged olive
Isonychia
Mahogany dun
Gray drake
Trico
October caddis
Saddle-case caddis
Golden stonefly
Salmonfly
Midge
Sculpin
Hopper
Leech
Crayfish
Baitfish
Beetle
Ant

 

September is usually two months in one. The first half often has inconsistent fishing and feels like a continuation of August. In the second half, cooler weather settles in, with maybe a little rain, and trout and steelhead respond to the change with gusto.

Fall fishing will arrive about the second week of September. Even if we have high peak temperatures, it's not hot for long. The nights are cooler and longer, and that means lower water temperatures overall. It's all due to the earth's tilt on its axis, and that ain't gonna change. Enjoy!

Trout. Trout fishing improves in September, and not just because of cooler water. After a couple of months of caddis-dominated hatches, two mayflies return to prominence this month: mahogany duns and blue-winged olives.

The mahogany duns (Paraleptophelbia) create trout feeding activity in quiet bankwater because that's where the nymphs migrate before hatching. If you see trout languidly rising in slow water near the riverbank this month, you're probably witnessing a mahogany dun hatch. DON'T cast blindly. In this quiet water you'll spook the fish. Instead, watch the rises and pick a single trout. Use a downstream presentation so the fly reaches the fish before the leader and line.

The other mayfly that returns this month is the blue-winged olive. Hatches will be sporadic, but nymphs are active and are taken by trout more regularly than the duns, especially in riffly water; see A Little Known Two-Fer-One for tips on how to take advantage of this.

Tricos are marginally important in Oregon rivers, but on a few streams, such as the Williamson, there are enough of them to create selective feeding situations. The hatch will continue into early September.

Caddis continue to be active. Most of the remaining hatchers are size 18-20, but the huge October caddis makes its appearance late in the month. Some anglers discount the importance of October caddis to trout anglers. I'm not one of them. From the Deschutes to the Metolius to small streams such as the South Fork of the Walla Walla, this is an important hatch. Trout take pupa patterns as well as adults. When fishing an adult October caddis pattern, you might try skating the fly if a standard dead-drift doesn't entice the fish.

Salmonfly nymphs, which are never totally off the menu for trout, will become more important this month. Two-nymph rigs, with a salmonfly nymph on the point, will be very productive when no hatches are in progress.

Steelhead. For many anglers, steelhead will be the biggest news of September. Most major summer steelhead streams are hitting their prime. The strength of the run will vary from one year to the next. As the sun gets lower in the sky and temperatures cool, you can be productive for a longer time each day, instead of restricting yourself to the early morning and late evening.

No matter which species you pursue, you will find slippery rocks this month. A summer of low rivers and warm sunshine will have encouraged thick coats of algae on many submerged boulders. Watch your step, and be prepared to fall in.

 

Lakes

Hatches divided by half-month.
 Super    Major    Minor    Slight    None

HATCH NYMPH/
LARVA
PUPA/
EMERGER
DUN/
ADULT
EGG-
LAYER
Callibaetis
Gray drake
Longhorn caddis
Dragonfly
Midge
Scud
Leech
Crayfish
Baitfish
Beetle
Ant

One key to September lake fishing is understanding the needs of different trout species. For example, brown trout will move toward inlet and outlet streams in preparation for fall spawning. Once they're in their spawning mode, though, leave them alone.

Want to know where to look for brookies this month? Any shallow place that has rocky structures or gravel. They, too, are getting ready to spawn. Unlike browns and rainbows, brook trout can spawn in stillwater (that's because they're a char, not a trout).

Rainbow trout, on the other hand, are spring spawners, so they will wait several months before looking for a place to propagate themselves. But they are always searching for good water conditions. So in lakes where the water cools off, they'll scatter and be hard to locate. In other lakes, the level will have dropped, the water is warm, and rainbows will look for cool water sources, such as springs, inlets, and deeper water.

The major trout foods in stillwaters this month are midges (mornings and evenings, primarily) and Callibaetis. Woolly Buggers and leech patterns will continue to produce, too.

Callibaetis hatches usually fade in intensity as summer progresses, and almost grind to a halt in August. But they often have a resurgence around mid-September. These late hatches are usually size 16 insects, and they are a little darker than the Callibaetis you saw earlier in the year. Carry Quigley Cripples and Sparkle Duns for the hatch; size-16 Rusty Spinners for the spinner fall; Flashback Pheasant Tails for the nymphs.