With respect to BWO and mahogany dun activity and steamer presentation on the lower river, what applies to the South Fork applies here. Wind can diminish the mayfly activity, but unsettled conditions do not hurt streamer fishing. Flow throughout is a bit below average for the time of year.
With the river so low below Island Park Dam (135 cfs today), it is time to pitch streamers into the big Box Canyon holes where fish will concentrate. Look for weeds braking up along the Last Chance-Harriman reach and fish responding to BWOs and what is left of early AM tricos. Hoppers along this part of the river are soon to be things of the past. The lower river now offers better fishing with BWO, mahogany duns, a fading hopper population and best of all browns responding to streamers. Look for streamer fishing to improve with the unsettled weather coming up in the next few days.
Look for fish responding to BWO, mahogany duns, morning tricos, afternoon caddis, ants, beetles and hoppers anywhere you try the river from Last Chance to below St. Anthony. Crowds are gone just about everywhere, but especially from the Last Chance-Harriman section. A killing frost could happen any day, especially on the upper river and wipe out hoppers and slow ants and beetles. But BWOs and caddis will remain active for quite a while. Streamer fishing will pick up on the lower river as browns begin to migrate.
Brown trout are beginning their runs to spawning areas. The best time to encounter them is in the evening or at first light in the AM. Use streamer and woolly bugger type patterns to encounter them. On windy days look for diminished aquatic insect activity. When the wind dies and if overcast and cool weather remains the BWO, mahogany dun and midge activity will return.
Flow out of Henry’s Lake has been cut in half. This means fish in the Flat Ranch section of the river will be moving downstream into the Henry’s Fork. Until we have a killing frost, terrestrial insect patterns will be most effective along the Last Chance-Harriman section of the river and also along the lower river. BWO life cycle patterns remain effective everywhere as will patterns for PM caddis activity.
Same story for the Last Chance-Harriman part of the upper river: AM trico, daytime terrestrial insect activity. Crowds have thinned considerably. Tiny BWOs are out on the lower river along with some mahogany duns. Terrestrial insects everywhere will remain active and thus available to fish until a killing frost.
Water remains a bit discolored from the big windstorm of September 7th. Some shoreline holds a lot of uprooted weeds.Water temperature near the surface is about 60 deg. F. that temperature keeps the biggest fish in deeper water. Weather will begin cooling enough to drop water temps to levels making big fish comfortable in moving around the lake. Better fishing days are coming!
The cooler weather predicted for next week should cool the lower river off enough to bring on the tiny BWOs and hopefully not hurt the terrestrial bugs. Pitching streamers on this part of the river during low light conditions will become increasingly effective as we move through the fall season. Noe might be the time to start building a supply of streamers and woolly bugger types for those resident brown trout.
Pretty much the same conditions as our report of four days ago. With respect to the lower river, terrestrial insect patterns work during evenings and early AMs. We are closer to cooling off and the resulting tiny BWO emergence. For the upper river’s Last Chance-Harriman section, tricos in the early AM and hopper and ant patterns after they quit. For presenting those patterns; long, drag-free floats over good holding water near banks and overhangs will bring results. Don’t shy away from a stout (3X) tippet when doing so. You will need it when tying into a really good fish that wants to get down in the abundant weeds.
Pretty much the same as last week. For the lower river fish early and late in the day and concentrate on terrestrial insect and caddis life cycle patterns. A lot of folks are fishing on the upper river where early AM tricos and daytime terrestrial insects (including ants), a few speckled duns, tiny PMDs, and later caddis and spinner falls bring action in the Last Chance-Harriman section. Two fly nymph rigs work well in Box Canyon.