The lower river offers BWO and midge activity with responding trout for the top water enthusiast and streamer fishing for the brown trout enthusiast. Now and during the upcoming weekend the upper river offers winter-like weather with BWO and midge activity and responding trout. Streamer and nymph presentation in deep Box Canyon holes and runs may entice a big rainbow to hit, but dress for winter especially with reliably leak proof waders.
Downstream from Island Park Reservoir flow is lower than normal at every gauge location. BWOs are abundant everywhere. Look for sheltered areas along the river for best activity from them and responding fish. Do not forget to place streamer patterns in that fly box, because brown trout are beginning spawning migrations and are in an aggressive mood. Low light conditions will give the best conditions for encountering them.
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!