Spring is here on the Gallatin River near Big Sky and Bozeman and outside of Yellowstone National Park. But, like with so many rivers this time of year, the timing of the day that you fish it, is crucial to success. During the months of March, April, and in early May the fishing action starts later in the day on the Gallatin. You've got to give time for the water to warm up. If a BWO hatch occurs, bugs likely won't pop until between Noon and 2 PM. Midges can hatch earlier, but there is no need to be on the water any earlier than 10 or 11 am. For nymphs a standard Gallatin River rig is a stonefly pattern in size 10 or 12--Pat's Rubber Legs is a top choice of local anglers. Follow the stonefly nymph with smaller beadhead mayfly or midge nymph. If Blue Winged Olives hatch look for fish to rise in a slow pool or slower current next to faster water.
Nymphing has been most productive for the majority of the day, with smaller midge and mayfly patterns usually being the most effective. After the noon hour be sure to keep your eyes open for rising trout, and the hint will be to look for hatching Blue Winged Olives or midges. When nymphing it pays to skip a lot of water and jump from one deep run to another. Look for steady currents that aren’t too strong but are still moving just enough to bring food to trout. Slow water that is 3-6 feet deep and located just below a riffle is always a good bet. Nymphing stone fly patterns trailed by a baetis nymph or midge larva is a good place to start, but egg patterns and worms are also good flies to try.
The Month Ahead:
The Gallatin River should remain a very legit option for fishing near Bozeman and Big Sky for the next month or so until runoff commences in earnest in mid-May. Even as daytime high temperatures climb, the majority of the mountain snowpack that can cause the Gallatin River to start runoff is in elevations high enough to stay frozen until mid-May. Hatches of BWOs and midges will dominate a trout's diet and the dry fly fishing and nymph fishing action should increase in duration throughout the angling day. A special thing to consider on the Gallatin is water color and clarity. Trout on the Gallatin River will feed in water that contains more color/sediment than many other rivers. In most years, it is the CFS level that deems the Gallatin River unfishable because in certain flows the river is just too high, fast, and unpredictable to safely fish on foot.
To get some useful knowledge and to expand your fly fishing horizons, be sure to read some of our recent blog posts featuring: 5 Best Streamers for Fly Fishing in Montana in Spring, 5 Essential Dry Flies for Spring, 9 Great Flies for Large Trout Anywhere in the World, What Do Trout Need And How to Use That to Catch More Fish, Best Not-So-Secret Places to Fish in Montana This Spring, and The Mayfly You Need to Know: Catch More Fish by Understanding Blue Winged Olives.
Flies for the Gallatin River for the Next Month:
Lightning Bugs in sizes 16-18
Juju baetis in black or olive in sizes 18-20
Firebhead or hotbead SJ worms in sizes 12-16
Sawyer PTs in sizes 18-22
Zebra Midges in black, red, or olive in sizes 18-22
Pheasant Tails in flashback or natural in sizes 16-20
Little Spankers in sizes 18-20
Pat's Rubberlegs in sizes 12-14
Long Term Fishing Forecast:
The Gallatin River near Big Sky and Bozeman is going to be a consistent local option with good two-fly nymph rigs from now until when runoff commences in mid-May.