Recently I wrote about a scouting trip looking for clean, cold water and how it can almost always be found. This post is about what to do if the water is a little less than clear.
I do not love fishing highly turbid streams but sometimes you just have no choice - other than not fishing, which seems like a terrible option. First, I think it is important to understand that water clarity is a continuum from gin clear to unfishably turbid. I like a bit of stain and I would generally prefer a bit of stain over gin clear water as it helps hide me a little bit and generally has the fish a little less weary. Heavy stain is hard to fish and in general, my first option is to go elsewhere - generally to a smaller stream that is likely to have cleared more quickly. Odds are pretty good that this will move me into that "sweet spot" of turbidity.
The biggest thing that turbidity does is limits the fish's window - the volume of water in which they can see potential food. Fish in turbid waters generally will not move as far for a fly than they will when the water is clearer because they simply can't see that far. A graduate school friend and roommate studied Brook Trout reactive distance and found that reactive distance decreased curvilinearly with turbidity (Sweka and Hartman 2001). Brook Trout also more actively searched and spent more energy searching for food at the highest of turbidities in an artificial stream. This is a long-term potential problem - sight feeding fishes do not do well in chronically turbid streams - but they can do very well in streams that are occasionally turbid.
Western anglers are generally accustomed to dealing with turbid water when runoff hits in the spring. With this spring runoff which is snow melt driven also brings water temperatures down. This is generally the winter and spring fishing "double whammy" which requires a special approach to catch fishes that are metabolically constrained by cold water temperatures. And it is not just a western thing, we of course, see spring floods here too, just no on the scale that most western fisheries experience. In the summer, turbid rivers can be fished more quickly with attention-grabbing flies, cold spring runoff streams require a different, more measured approach. I have written on this before in posts "In Praise of Winter Fishing (sort of)" and "Finding Clear and Cold Water".
Fish Senses
Fish sense the world differently than we do (no, kidding...). Fishes obviously have eyesight but light travels differently through the water than it does through air. It is relatively difficult for us to assess just how fishes see and process what they see. There are scientific arguments about just how well fishes see color and if / which fishes sense UV light. For trout, there is some evidence that they see in the UV spectrum when they are young and use zooplankton as a food source but lose that ability as they grow larger and move to larger prey items. Some wavelengths of light travel deeply through the water column (blue) and others are quickly attenuated and disappear at relatively shallow depths (red). And in turbid water, light in more quickly attenuated than in clear water. Under these conditions fishes may use different senses.
Two senses that fishes of turbid waters have that are often elevated are their sense of smell and hearing / ability to sense vibrations - largely through a lateral line. It should not be a surprise that fishes that live in chronically turbid water - like catfishes - have a very strong sense of smell and sense their environment largely through that sense. Trout on the other hand are fishes of clear waters - as are smallmouth bass. However trout and smallmouth both are effective at using their lateral lines - perhaps you have spooked a few while wading. However streams are pretty good at dampening vibrations - which is why riffles and other broken water is often easier to fish than are slow pools and glides.
Fishing Streamers
As turbidity increases, I am much more likely to be fishing streamers than at other times when I much prefer to fish dry flies. Yes, I have made no secret about it - I am a dry fly "snob". But I do enjoy fishing streamers - just not as much as I like the dry fly take.
Streamers provide, 1) a significant profile that is more visible to predators, 2) provide a vibration that fishes will feel in dark waters, and 3) because of the first two points, they can cover turbid water more effectively than other fly choices. Honestly, the best choice in really turbid water is probably a Panther Martin in a dark color. It throws off a Hell of a vibration, one that is really difficult, if not impossible, to imitate with a fly.
My choices of streamers in turbid waters are dark; black with a bit of flash. A rattle or a large water pushing head go a long way to improving the "feel" of a stream in turbid waters. I know Muddler Minnows are maybe "out of style" but that water pushing head will never stop working. Trout in really turbid waters need to feel a fly through their lateral line - bulk, rattles, and water-pushing heads help with that. And fish those streamers on a sinking line or sinking leader to get them down.
Fishing Nymphs
I will readily admit that there was a time that I chased turbid water and my go to fly was a red San Juan Worm. It is absolutely deadly on a receding stream. It depends upon the stream but a day or so after a decent rain and nearly unfishable turbidity. As the stream starts to clear and you can make out your boots in mid-shin deep slack water, that is the time to go fishing.
Twenty-plus years ago, there was a fish I was "hunting". I had her (they're almost always "girls" at that size) on twice before, both times as the days were turning dark. Once on a pheasant tail nymph, the other time on a sulfur sparkle dun, but I never had much chance on 5X tippet. So a day or two after a good "gully washer", I went to where I knew she was holding. It was a deep pool that dropped off from a shallow riffle to one of those holes that will float your hat. The hole no longer exists but back then, I called it "double pool" - all good pools have names - because the riffle was maybe 6 to 8 feet in length and separated a pretty good pool above from the REALLY good pool below. I had on the trusty red San Juan worm below a heavier nymph and that rig was under a "bobber". This time, given the advantages of turbid water, I was able to fish a heavy tippet - probably 3X. She hit again, right as the flies were falling off the steep slope. And I knew it right away - you've felt those sort of head shakes where you know that it is a big fish. And I should have had a chance but I didn't - she used the steep drop off to rub the tippet against and fairly quickly broke herself off. I never did get a chance to go back with even heavier tippet. While it was a fun remembrance for me, there are a few lessons there too, I think.
Turbid water gets a bad name - there are some significant advantages that the angler has in muddy water. First, you are less likely to spook fish - a shorter leader, heavier tippet, and a shorter, closer approach are all more possible. Turbid water will also allow you to fish bigger beads and more split shot without spooking fish (as much). In general, I am fishing larger, heavier nymphs in turbid water. Nymphs that present a significant profile and are flashy or dark are more likely to be noticed. Fishes in turbid water are rarely overly picky - they can't afford to be. I find that statement to be more true for more significant flow events. If a stream takes three or more days to become "fishable", the hungrier that trout are likely to be. Some of my favorite nymphs under more turbid conditions are Prince nymphs, guide's choice hares ear, Whitlock's red fox squirrel nymph, and, of course, the San Juan worm which is really unbeatable. This is a time when for "Euro" nymphing - or at least the tight line approach where you methodically cover the water is a huge advantage. And it is, maybe, a time for winged wet flies that provide a significant profile like a March Brown, Leadwing Coachman, Silver and Black, or other similarly dark winged wet flies.
Fishing Dry Flies
While typically turbid streams means that the dry fly bite is "off", there are times when 1) a slight stain is very helpful, and 2) in a heavy stain, a large, obnoxious fly can be just the ticket. I have gotten away with fishing some exceedingly large and obnoxious foam behemoths during this time. There is no good reason for it but I have had pretty good luck on bright pink and royal Chernobyl Ants. Don't be afraid to allow that fly to hit with a bit of "authority" - sometimes that helps draw a little attention. I am guessing, because I have never done it, but a mouse or even a popper might be a good choice during really turbid water.
All things being equal, I like a bit of stain - where I can just see my shoes in knee deep water, that is the sweet spot for dry fly fishing. Much more stained than that and you are fighting fish not being able to see your fly. But the right amount of stain is great and puts the odds a bit more in your favor. It allows you to go with a bit heavier tippet - maybe 3X or 4X instead of 5X - and maybe a bit shorter tippet to make your casts a bit more accurate. When things are overly turbid, hit the slack water areas and the banks. It can be tough to fish dries in turbid water but the right amount of stain is a huge benefit.
Summary of Fishing Turbid Streams
Fishing in turbid waters is sometimes a necessity, sometimes a joy. Around here in the Driftless where there are thousands of miles of streams, you can always find clear water - if you are willing to move upstream. If you have no choice but to fish really turbid streams, above are some suggestions for fishing those streams more effectively. I will say that when you couple turbid streams with cold water - like in spring runoff - fishing can be particularly difficult.
However there is this sweet spot where a bit of stain helps the angler. I generally start with a streamer as they have the strongest physical and acoustic profile. As the stream gets clearer, I may opt for a nymph. A dry fly is generally my last choice for turbid streams - though I will say there have been times that a bold dry fly can draw them up but I usually wait for streams to clear a bit before I come back to dry flies.