Fly Fishing Freestones Vs. Tailwaters
Fishing the Bozeman area is unique based on the immense amount of fishable/floatable waters. With over 225+ miles of cold trout holding waters within an hour drive of our Bozeman fly shop there is going to be significant differences between the water you fish one day against the water you might be angling the following day. There are two basic types of fishable rivers, both are found close to town. The first is a freestone, or undammed river, such as the Gallatin. The second type of river is a tailwater, or dammed river, an example being the lower Madison. Both of these have different aquatic insects and fish differently.
Rivers like the Yellowstone and Gallatin are fast moving rivers where the bed consists of large rounded rocks. The overall biomass of aquatic insects is lower and there is a greater amount of stoneflies. Lacking a massive food supply, the fish in freestones tend to be more opportunistic and less picky about what they consume. This is important to consider when water temperatures start heating up and fish activity increases, and in the fall when water temps decrease from the excessive summer heat. Attractor patterns become very important at these times for both nymphs and dry flies. Flies that will consistently fool fish include Prince Nymphs, Pat’s Rubberlegs, Stimulators, and Royal Wulffs. Big flies that will imitate a stonefly is key. Rowing these types of rivers is usually a bit more technical and dangerous due to the fast nature of the water and how huge changes occur yearly. Identifying fish locations on freestones tends to be easier with fish holding on seams and other breaks in the quick water. Throwing flies into pocket water behind boulders will pick up a lot of trout. Freestone rivers become unfishable during high water without their flow being controlled by a dam. Fish locations change with the seasons from slow when the water is cold, to fast when the water warms. In fewer words; fast water, big bugs (stoneflies), and attractor flies.
Fishing the Lower Madison, the classic Bozeman area tailwater, is going to be more specific when trying to feed fish. Huge biomass of aquatic insects makes the trout much more particular about what they eat. Crustaceans such as crawfish and scuds are prevalent and make up a significant portion of a fish’s diet. The flies we fish are smaller and much more specific to the season. Matching the hatch is the name of the game for tailwater fly fishing. Bed substrate consists of smaller rocks and more silt. This type of streambed is a more suitable habitat for a lot of mayflies. BWO’s, PMD’s, and brown drakes hatch in huge numbers where stoneflies are found in smaller numbers or not at all. Finding fish is more difficult because slight changes in depth may not be noticeable on the waters surface. Generally, tailwaters are easier to row. These remain more fishable and clear throughout high water as flows are controlled by a dam. Dammed rivers have less temperature variation throughout the year.
The Upper Madison, although it is a tailwater, fishes for the most part like a freestone river. Many aquatic insects will be found interchangeably between freestones and tailwaters, but these general rules are important to consider when fishing around Bozeman. Midges are everywhere. Hiring a Fins & Feathers guide for a couple days is a great way to learn all of this information first hand.