A cool Autumn has settled into the valley, with daytime temperatures hovering in the mid-fifties. The occasional day of rain is also in the forecast so check your weather and plan your fishing days accordingly. With the rainy days, comes the clouds, which when it is not raining, these clouds can in turn bring clouds of the Fall Baetis. There are still very few anglers out and about for this time of the year, so get out and enjoy one of the best times of the season in the Sun Valley area!
This is a great afternoon fishery and no one needs to be in any rush to get down there. The later you can stay the better. Prime hours are between 12:00 and 5:00 p.m. Look for Callibaetis all over the Creek with good reports of them showing on the lower stretches of river, downstream of the Hwy 20 Bridge. This is also a great area to catch the seasons biggest Mahogany Dun hatches. When the clouds come in and the wind is calm, it is Baetis time on the river. Although the insect is small the fish are looking to fatten up for the winter so they will take advantage of whatever hatches and spinner falls they are able to. Be very ready as well, for the Mahogany Dun, despite its large size can become a hatch that is easily masked by the Baetis. The Mahogany is difficult to see and will hatch in waves while the Baetis is on the water. Anglers will draw strikes on the tiny Baetis and then suddenly wonâ€™t only to find the fish have switched insects for a few moments. If you arenâ€™t paying attention, they will switch back to Baetis at a moments notice, so once you start seeing the Mahogany, pay very, very close attention to them! The masking hatch is one of the trickiest and most interesting puzzles fly anglers are ever presented withâ€¦
Big Wood River
The Wood is really fishing well when the weather is calm. The Fall Baetis is the main player on the river with intense afternoon activity under the right conditions. If you want to cover a lot of water and cast bigger dry flies, the October Caddis and the Hecuba are still out and about. A large H and L Variant is an anglers best choice during this time of the season. A few small nymphs fished in tandem are also a good bet. Use Pheasant Tails, Zebra Nymphs and tiny Copper Johns, fished together or dropped under a larger nymph like a Hareâ€™s Ear or Zug Bug. The evenings on the Wood this time of year also provide a nice opportunity to fish an evening Midge hatch which may last well into the evening twilight. Enjoy the low easy to wade water and the serenity on the Wood these days, it is well worth your time!
Upper Lost River and Copper Basin
These rivers are all but deserted these days. The fishing is fair with a lot of Whitefish moving through the system. If you are nymph fishing expect to catch quite a few of these indicator species. There are still plenty of nice trout to catch, with the lower basin stretches being the areas to key on. Start as close the end of Trail Creek Road as you can and then work your way up river toward the turn into Copper Basin. Be prepared to cover a lot of water, but also be prepared to have an entire trophy trout system to yourself! Try small attractor patterns, Grasshoppers and small bead head nymphs. If you really are catching a lot of Whitefish and fewer trout, put on a streamer fly like a Woolly Bugger, or Matuka and swing it downstream in the deepest, most structure filled areas you can find, and then stay ready for some very hard strikes.
Big Lost River
Very low flows with a little tint to the water is what may be expected on the lost below the Mackay dam. This has set the fishing back some, but anglers can still take fish using nymphs and by also targeting the afternoon Baetis hatches, but the rivers biggest fish are going to be taking subsurface. Red colored Nymphs like San Juan Worms, Copper Johns, and Zebra Midges are all good choices. Standard nymphs like Princeâ€™s are also a great bet.
South Fork of the Boise
The low flows continue on the South Fork, with the Fall Baetis being the main attraction. Hoppers and some nymphs will also take fish, but the real show is on cloudy, calm days when the Baetis seemingly blanket the river. With the low flows, comes a few more anglers especially on the weekend, so if you can find a cloudy day in the forecast with little rain, and itâ€™s a weekday, one may want to consider playing hooky and getting to the river for a long afternoon!