Trout fishing on the Middle Fork of the Salmon River is primarily a summer activity. The season (even though catch-and-release) does not open until Memorial Day. In normal years the river is too high to effectively fish at that time, and remains high until late June. The Middle Fork is dam-free, so flow is a function of snow-melt. Fishing is better at river levels below about four feet on the guage, which in a normal water year means late June-early July on through the summer. In low water years, the river can be low enough to fish throughout June, and fishing is good then.
During July and August, water temperatures are typically mid-fifties through sixties, with about five degrees increase from daylight til mid-afternoon, and similar loss overnight. River temperature increases as the trip progresses, with loss of elevation, and also increases as the snow run-off decreases toward mid-summer. During the heat of the summer, late July to early August, the river temperature can reach 70, especially in low-water years. Fishing slows greatly at that temperature. However, 70 degrees is not an every-year event. July and August are the driest two months, with normally clear water. September is often touted as a good fishing month, and it is, but the chance of rain increases. With rain comes the chance of runoff from areas of recent forest fires, creating muddy, unfishable water. Often storms producing run-off are very localized, with a particular tributary causing the river to be off-color, but other tributary streams may be fishable. There are several tributary streams that are large enough to fish, with a trail along them. After September, weather becomes pretty chilly for camping and white water, and there is little activity on the river. By late October, there is often ice floating down the river.
The Middle Fork is a wilderness river, one hundred miles between road accesses. A typical float trip last six days. Most people travel in inflatable boats, but the classic Middle Fork fishing trip uses McKenzie River drift boats. These boats have been used since the beginning of floating on the Middle Fork in the late 30s, brought over from Oregon by outfitters and guides such as the Helfrichs and Pruitts. McKenzie boats were developed to fish in fast water. They are very responsive, comfortable--and fragile. Inflatable boats, both conventional and cataraft styles, are often equiped with knee braces, etc, to facilitate fly fishing. If kept light, they are nearly as nimble as a McKenzie, more forgiving of the occasional bumped rock, and can be flown into a river-side airstrip during low-water conditions. They are functional, but they are not as comfortable, convenient, or as dry in white water as a McKenzie. If you drop your scissors in an inflatable, they are in the bilge under a tube or the bottom of the river. An unexpected wave can wash unsecured tackle over the side, while that is much less likely in a McKenzie. And there is something special about a McKenzie River drift boat in fast water.
West slope cut-throat trout are the primary objective on the Middle Fork. The Middle Fork is in a granite drainage and has relatively low mineral content, as well as many months of cold water. Cut-throat mature at 12-15 inches here, and rarely exceed that length. There are also a lot of steelhead smolts, about 7-8 inches, resembling small rainbow trout. There are occasional mature, native rainbows similar in size to the cut-throat. If you fish deep, you will catch bull trout, especially with spinners. We seldom take them on top with dry flies. While fish aren’t huge, numbers are pretty good. Thirty to forty fish per day per boat is a reasonable expectation. With good fishing and good fishermen, that can be doubled.
There usually is not a great deal of surface activity by trout on the Middle Fork. Occasionally on the upper river there will be very heavy caddis hatchs, but still not a lot of surface activity by fish. There are salmon fly hatchs, but not of the scale of the sothwest Montana streams. Later in the summer there is a lot of grasshopper activity. The Middle Fork provides good dry-fly opportunity, with fish being not especially particular. Matching fly to particular emerging insects is not a major issue. Common patterns are elk-hair caddis, parachute adams, stimulators, grasshoppers, and humpies--but many flies will work just fine. I mostly use a simple elkhair caddis, size 8, with a red body. Some people scoff at that as being old-fashioned and obsolete, but if fishing is slow the situation is rarely improved by a different pattern. For fishermen who can handle a dropper, adding a beadhead (copper john, pheasant tail, etc.) can be very effective. It can also be a pain in the neck (literally) if casting skill is a little rough--may be more trouble than it is worth.
I have always been more concerned about placement of the fly than pattern. Tournament-distance casting is not necessary if the boatman does his job. A moderate length but accurate cast is all that is needed. Wind is usually not an issue on the Middle Fork. A five-weight rod works very well. A heavier rod can get tiring after a long day. Usual fishing water includes eddy lines, cushions above rocks, and next to cliffs.
Not all outfitters are particularly interested in fishing. Unless arrangements are made for a fishing-focused trip, you may be on your own, fishing from camp or from a loaded inflatable boat as you float in mid-stream. Your boatman may be a fisherman, or may not know a fly from a spinner. Other outfitters are totally focused on fishing.
A pitfall of fishing the Middle Fork of the Salmon River is that a person easily becomes so absorbed by the fishing that the beauty of a mile-deep canyon passes by unnoticed.
