We just received the preliminary report from the Idaho Fish & Game Department with their population estimate for the Box Canyon. The trout numbers are simply astounding! There are 6200 trout per mile in the Box Canyon. It is the highest numbers ever recorded and more than double the long-term average. The increase in population can be directly attributed to winter flows in 2011-12 and 2012-13. During those periods the average flow from the Island Park Dam was more than 500 cubic feet per second, more than double the average flow for that time frame. More water means better shelter for young-of-the-year trout, milder water temperature, and more food.
Box Canyon has always been a strong indication of trout numbers throughout the Henry’s Fork, especially the Harriman State Park section. Not only was the trout population up but biologists reported seeing lots of large fish. This leaves little reason not to anticipate a superb fishing season in the Ranch and surrounding waters. The summer of 2012 was great on the Ranch. We’ve already experienced terrific fishing on other sections of the Henry’s Fork to back up what the biologists have said. All in all we expect the summer of 2013 to provide some of the best fishing in years.
While most of the Henry’s Fork has been open to fishing year round, the section from the Ashton Dam downstream to the Vernon Bridge and from the South Boundary of the Harriman Park to Riverside Campground open on May 25th. Here’s my report and forecast for the coming week.
Upper Henry’s Fork
The upper river from the confluence of the Henry’s Lake Outlet downstream to McCrea Bridge is fishing well. There are some hatches of mayflies and caddisflies but the main focus in this section should be the fast water at Coffee Pot Rapids and below. This is great Salmonfly water. Look for adults along the banks in the willows and shrubs. You can also look for nymph shucks in the rocks. This water is frequently high and off-color early in the year but the water is in good shape. If you can’t raise fish on large stonefly dry flies, try fishing black or brown Rubberlegs in the runs.
The Box Canyon will be busy, especially since the report from the fish and game was published. Our guides have been fishing the Box over the past several weeks with great reports. There have been Salmonflies emerging from the campground upstream to the confluence with the Buffalo River. Look for Salmonflies on the lower Box Canyon. Our favorite Salmonfly patterns are Henry’s Fork Foam Stone, Drowned Stone, Flutter Bug, and Red Elden’s Ant in size 4 or 6. If you don’t score with dries try a black or brown Rubberlegs with a Bead Head Pheasant Tail as a dropper.
Dry fly fishing has been good at Last Chance. There have been good hatches of Blue Winged Olive and March Brown mayflies, especially on cloudy days. You can also expect caddisflies to become a serious factor as the weather warms up. You can also score with dry Salmonfly patterns from the Last Chance boat ramp upstream to the mouth of the Box Canyon. There are many good patterns to use for the mayfly and caddis hatches. Stop in or call one of the fly shops for their recommendations on the best patterns.
Closed to fish until June 15.
Wood Road #16 – Pinehaven
The flat water from the south boundary of the Harriman State Park at Wood Road #16 downstream to Pinehaven will provide a great opportunity to test your skills on big selective rainbows. Look for Blue Winged Olive mayflies, March Browns and caddisflies. This water can also provide some great midge fishing. Another insect closely related to the midge is a terrestrial insect called a Bibio. These dark two winged flies are often found floating on the surface of the waters at Wood Road #16. There is no guarantee they will be out but if they are, the trout will eat them. Use a size 16 dark midge pattern with a very slender body.
The deep canyon from Riverside Campground downstream to the Stone Bridge below Warm River will be a great place to focus attention through the coming week. Salmonflies are thick in this section and the trout are looking for them. Some of this water is navigatable but requires a very experienced oarsman. You can float from Riverside Campground to Hatchery Ford and from the Grandview Slide below Lower Mesa Falls to Stone Bridge. Both of these sections have some whitewater that can kill you if you don’t know what you’re doing. There is also good wading access at Riverside Campground, Hatchery Ford, and Bear Gulch. There are also several trails that go deep into the canyon at Wood Road #6 (FS #151), Sheep Falls and Grandview. If you hike down the trail at Grandview be aware that boats may be sliding down the trail. I like to walk upstream from the Grandview Slide where not many anglers fish.
Warm River to Ashton
This is a high traffic area but it has been very productive with Salmonflies. The big stoneflies should finish up during the coming week but smaller Golden Stones will be active for the next several weeks. Use the same flies recommended for Salmonflies but with Golden Stone colors and sizes. I like size 8 or 10. Some of the most productive fishing can be by wading when the river is crowded with float boaters. There is good access from Fisherman’s Drive on the north side of the river above the highway 20 bridge and downstream from Stone Bridge. Some of the adjacent land is privately owned so make sure you have legal access. In Idaho you are legal within the high water mark of the river as long as you access the river from a legal access.
Ashton Dam to St Anthony
This tailwater stretch of the Henry’s Fork is always very popular in late May and early June. Salmonflies are finishing up and Golden Stoneflies are on the way. Caddisflies can also produce good fishing.
St Anthony to Confluence
This water is often too high and roily to fish well this time of year but this year the runoff is coming slower and lighter than normal. The water is in good shape to be productive and should stay that way unless the weather gets unusually warm. Streamers are productive and Golden Stoneflies are starting to happen.
Henry’s Fork Tributaries
There is good access to lower Warm River near the campground. Warm River is a good option with stoneflies, attractor dry flies, and nymphs. Warm River is stocked with catchable trout near the Warm River Campground and is a good option for young anglers.
Fall River is pretty high but fishable. Look for Salmonflies by the first week of June.
Henry’s Lake Outlet needs more water to move some fish out of Henry’s Lake. There have been some decent trout caught but not in the numbers of the past few years.
Opened for fishing on May 18.
Henry’s Lake should be good but I guarantee it will be very crowded during the Memorial Day weekend. We’ll provide more accurate information after we have more details.
South Fork of the Snake
The water is pretty high but coming down. There is really no reason to go to the South Fork with all that is going on the Henry’s Fork. June should be a very good month on the South Fork because Palisades Reservoir is only 43% filled as of this writing. The river should be in good shape while the reservoir fills over the coming weeks.
Yellowstone National Park
Focus on the Firehole and Madison.