Heavy grass beds abound in the Firehole
Heavy grass beds abound in the Firehole

Guest Blogger: Mike Cline, Bozeman, MT

Firehole Fly Box (discussed in my previous post) in hand, what’s my approach to this storied river. The Firehole is unusual in the sense that for the most part, it is a river that runs over solid volcanic bedrock and doesn’t have large concentrations of loose rock or cobble and few large boulders. From Biscuit Basin all the way to Firehole Canyon, long sections of the river contain extensive mounds of aquatic weeds rooted in muddy soil. Those weeds and their long flowing tops provide cover for trout from one side of the river to the other and make traditional nymphing with an indicator nearly impossible. I am always surprised by how many anglers try anyway.

In the more wooded areas of the river, deadfall provides a lot of streamside cover for trout.

Deadfall holds trout above and below
Deadfall holds trout above and below

The Firehole Fly Box doesn’t require a big stick. Three or four weights are sufficient and much more fun with the smaller Firehole trout than bigger rods. My favorites are my Scott F703 and Diamondglass 7’ three weight glass rods. However, if it is going to be a bit windy, then I’ll turn to my Orvis Superfine Troutbum 7.5’ 4 weight in tipflex. Although super long casts are never necessary on the Firehole, these rods with double taper lines will handle the width of the river in most places. Also, in the narrower wooded sections between the 2nd Iron Bridge and Biscuit Basin, the shorter rods excel. The only time I’ll break out the 5 weight is during the first weeks of the season when the water is high and using a 150 grain sink tip is the best way to get flies in front of trout in some sections.

Fishing from the middle
Fishing from the middle

Approach and presentation is the one thing that I think most unsuccessful Firehole anglers have trouble with, especially if they are hoping to catch better than average fish. In my experience, the largest fish, especially the largest browns are tucked into the undercut banks or hugging the bottom pof deep runs. They aren’t cruising around in the pools, riffles and weed filled runs daring the pelicans, herons and ospreys. They are on the edges of the stream—the sides, the deep bottoms. When there are significant hatches going on, fish seem to be everywhere (and they are), but careful observation along the banks will reveal subtle rises tight to the bank in little nooks and crannies. These are the better fish, and for the most part that’s where they are all day, hatch or not. In some cases, especially on outside bends, the undercut can be over a foot deep providing cave like hiding spots for the trout.

Undercut banks hold larger fish
Undercut banks hold larger fish

Presenting a fly (dry or wet) to these fish is very difficult if you are standing on the bank. You really need to position yourself in the middle of the river (depth allowing) and fish the banks from there. Fishing from the middle as I call it has several advantages. Whether you are staying stationary (pounding one group of rising fish), fishing upstream with sparkle duns or elk hair caddis, or moving downstream swinging buggers and soft hackles, the middle gives you easy approaches to both banks of the river. In the wooded areas, back casts are less likely to snag on trees or brush. But most importantly, fishing from the middle allows you to see those subtle bank side rises and put your fly right on their nose without disturbing them as you might from the bank.

A bit of postscript. In January 2013, Bruce Staples released his “Flies for the Greater Yellowstone Area”. It is really a nice compilation of over 500 patterns that are useful here in the Yellowstone area. In 2012, John Holt, a veteran Montana angler published: “Stalking Trophy Brown Trout: A Fly-Fisher’s Guide to Catching the Biggest Trout of Your Life”. I didn’t get my copy until this January so I didn’t make the connection between Holt’s book, Staple’s book and my thoughts about the Firehole until recently. Of course Staples’ book is for those anglers who like to have lots of different patterns in their fly boxes. Nothing wrong with that. Holt on the other hand comes the conclusion that when he used just one pattern all day, he catches just as many fish as when he uses a bunch of different patterns. That’s pretty much the way I feel about the Firehole. On any given day you can be successful with just a few patterns. Match the fly to your favorite methods—dry fly, swinging soft hackles, or streamers and stick with it all day. Lighten your load and fish the Firehole with the Firehole fly box.

5 Comments

  1. Loved this two-part article about the fabled Firehole, Mike. Been there…never fished it…wish I had…hope to some day.

    Focusing on undercut banks is logical of course. To what extent do you also concentrate on the very edges of the large weed clumps, treating them as though they were submerged “banks”? Reason I ask is: There are large clumps of subaquatic weed where I often fish, but to my eternal consternation so far I’ve not found them to have concentrations of fish lurking right along their edges. Or maybe I’m just not fishing those clumps right.

    – Mike

  2. Mike, not sure I can do justice with just words to answer your question as a drawing would be much easier. For this explanation, assume the bedrock river bottom is relatively flat and the depth of the bedrock is 3′-4′. Then visualize a human head facing upstream wearing a ball cap backwards with the bill facing downstream. The head sits on the bedrock and the top of cap just breaks the surface. The head represents the accumulation of mud that is home to the large clump of aquatic weeds. The ball cap including the bill of the cap represents the weeds. Underneath the bill of the cap there is a void which provides cover for trout. The front half of the weed clump provides no cover, including at the edges. But the back half of the clump is basically a big awning in the river where fish can be secure underneath it. So when fishing around weed clumps on the Firehole, I always try and target the last third of the clump getting buggers and soft hackles as close to the edges of the cap bill, including just downstream from the end of undulating weeds. When there’s some good hatches going on fish will move out from under the weeds but not to side, but usually just dropping a bit downstream in the current break caused by the weed clump.

    The most difficult thing to describe to anyone who hasn’t seen it, is the fact that the Firehole flows on top of volcanic bedrock and there’s very few places other than at the edges where it has actually eroded anything. Most large obstructions in the flow have fallen into the river at some point. It is dramatically different than a traditional freestone stream. If you can imagine pouring a continuous flow of water on a slightly sloped sheet of glass and another flow on a slightly sloping area of sand or mud what the difference might be. The sand/mud substrate would erode and continue to alter the nature of the river bed, while the same flow on the glass would erode nothing. Of course the volcanic bedrock is not smooth or flat and the jaggedness of it and changing depth tend to create the same kinds of holding water as traditional rivers but it really different from traditional rivers.

  3. Very clear description Mike, thanks. And despite the volcanic slabs over which the Firehole travels, I can still liken your description to my own usual haunt (even though it’s a freestone and sand stream). The “human head” clumps of soil and root are large and often wide, but the weed does “flag” downstream and provide cavities underneath where one would expect trout to hide.

    Two things you said just there lit a lightbulb: “…Fish will move out…but not to side…” and “…target the last third of the clump…including just downstream….” Me attempting to lure trout out to the side is asking them to come out into the swifter current for my offering. I suspect that might often be asking too much. There’s a reason why they hold in eddies and protected pockets–they can’t afford to work that hard for snacks, each of which may give them less fuel than it took to go into the swift stuff and grab it.

    Thanks Mike, concentrating on the tail of the streaming weed makes perfect sense.

    – Mike

    1. Pat, put some volume in those warehouses so you can get that bonus and afford the trip. Get here and we’ll commence to catching.

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