Whether you are fishing our meandering valley river bottoms or the alpine lakes high above, fly fishing in central Idaho is absolutely excellent at the moment. Trout are feeding aggressively on the various mayfly and caddis floating down our local freestones and the morning activity at Silver Creek is at its annual peak. Mornings and evenings lend themselves to more active dry fly fishing but midday can be very exciting with grasshoppers and various other terrestrials. All in all, it is an excellent time to be on the river, whichever river you choose!
The annual “Trico Madness” featuring our world class Trico spinner fall has been underway for about three weeks and is now reaching its peak. Expect the action to heat up around 7:30 am and continue until about 11:30 am, depending on which section you select to fish. Initially, throw Trico duns to imitate the early spinners before they drop their wings. As the morning progresses, look for a significant Baetis emergence which will become evident as the diminutive olive mayflies climb up your waders before drying their wings and flying away. PMDs will also have a presence later in the morning and can be effective patterns to use as a quick respite from the continual Trico/Baetis fly rotation. Changing flies regularly is very important when fishing the Creek this time of year as fish will identify the imitations and disregard them. Sometimes switching between dun and spinner patterns should be done every half-dozen casts. As soon as your once-effective fly begins to float over the trout pod without success, take the initiative to switch patterns and revel in the next strike which will likely come immediately on a well-presented downstream cast. Once the morning window closes, try throwing terrestrials against the banks or floating blue damselflies along weedbeds mid-stream.
Big Wood River
The Wood is fishing very well, especially in the mornings and evenings. Mayflies, such as Pink Alberts (size 16), Tricos (size 20-22) and Baetis (size 18-20) are most prevalent in the mornings but the larger Pink Alberts will be present throughout the day. Also notice the small yellow Cranefly (size 14) present in decent numbers. During the heat of the afternoon, try throwing cream or yellow-bellied foam Grasshoppers along seams or against banks. Fish are looking up for these large meals and will rise to the surface from their deep summer haunts to snag such a nutritious meal. When the hopper action is mediocre, add a mayfly nymph, caddis pupae (size 12-18) or a Zebra Midge (size 18-22) off the hopper’s hook shank one to three feet, depending on the depth of the water you are fishing.
Big Lost River
The Lost will fish well through the end of summer and improve through September. Expect to see a smattering of mayflies including Baetis (size 20), Pink Alberts (size 16-18) and increasing numbers of Tricos (size 20-22) over the next week. Flowing at approximately 300 cfs, the river below Mackay Dam is at a prime level for fly fishing. In addition to mayflies, expect to see the large Cranefly and try imitating this insect with quartering-down presentations to the opposing banks. Often, this technique can pull large ‘bows from the bottom that are not otherwise actively feeding. Large nymphs such as Prince Nymphs, Flashback Pheasant Tails and King Princes (size 12-18) are the standard selections on this little tailwater fished under a strike indicator. Combining these large patterns with the petite Zebra Midge in black, brown or red (size 20) can also lead to a productive day subsurface.
Upper Big Lost
Although the various forks of the Lost have seen a good amount of pressure this summer, fishing remains very good along the East, West and North Forks. Use large attractor patterns such as cream Elk Hair Caddis (size 12-16), PMDs (size 16), Parachute Adams, Adams Wulffs, Irresistibles (size 12-16), Black Flying Ants (size 14-18) and Grasshoppers. In late August the Flying Ant takes on a more significant roll for feeding Rainbows, Cutthroats, Cuttbows, Brook Trout and Whitefish. Don’t hesitate to start with this pattern and revisit it frequently throughout the day.
South Fork of the Boise
The South Fork of the Boise remains at 1600 cfs although we can expect the flow to be lowered as September approaches. Check the streamflow chart before heading out to this tailwater as daily changes are inevitable. Look for Pink Alberts (size 16) to lead the charge here as well as the Golden Stone (size 14) and a variety of caddis and micro caddis. Use foam Grasshoppers extensively, dropping mayfly nymphs and caddis pupae (size 14-18) from the larger terrestrials above. Streamer fishing is also an exciting option as behemoth Rainbows and Bull Trout lurk below in the deeper runs and holes as they wait for crippled minnows to float by making for aggressive strikes.
The Salmon is currently on fire. Caddis are everywhere and are even falling from the riverside shrubbery into the water where waiting Rainbows, Cutthroat, Cuttbows, Bull Trout, Squawfish and Whitefish are sipping them up aggressively. Try throwing cream Elk Hair Caddis (size 14-16) as your â€œgo-toâ€ pattern. Orange-bodied Stimulators (size 10-14) are also good options for ravenous Cutthroats. Dropping large Prince Nymphs, King Princes, Flashbacks and Copper Johns (size 12-16) will also produce excellent numbers of strikes. Be aware that some sections of the river have been closed to floating due to the oncoming Chinook Salmon spawning period and that upper sections of the river above Clayton have become shallow making for difficult, rocky floats. This is no obstacle to superb fly fishing though, as the walk-and-wade fishing is excellent!