What colors do Steelhead see?

Discussion in 'Steelhead' started by Randru, Nov 25, 2009.

  1. I was talking with the owner of the local fly shop and he mentioned hearing that Steelhead are initially prone to hitting flies that are chartuse and purple. However he also mentioned that, the longer they stay in freshwater and the more their bodies acclimate to it their vision also changes and they are more likely to hit a red, orange or somewhat similarly bright colored fly. As I understand many claim that they bite not from a feeding instinct but a curiosity or aggressive impulse.

    I am just getting into the sport and the information I read is as varied as the source. Any comments on this is always welcome.

    1. Do Steelhead tend to hit the lure based on how their vision is affected by being in freshwater?

    2. And while they may not be voraciously feeding those who pump the stomachs or gut them for the table claim that they do feed. If so is it possible to key in on this aspect and choose flies based on their diet? And what might that be?

    Thanks for any advice.
     
  2. I won't take up the color issue as I've seen and caught steelhead on every color I can think of. Regarding feeding in freshwater, I believe it depends on the river. My adopted HW, the Trinity in No CA, is a tailwater that runs 47-50 degrees all winter in the upper reaches. It has incredible insect life, Skalwa, BWO, callibaetis, Isonychia, caddis, drakes, stones, sally's, etc, etc. all year. A friend took 3 fish on a #12 adams last January; he says they were sipping Isonychias like trout. I watched some steelhead in the 1st pool below the hatchery (closed water) this week taking up feeding stations and sipping grey drakes (#16 +/-) like crazy. I have had good luck with #14-16 emergers fished on a dry line during a hatch. I don't know if it's instinctive reation or any of the other numerous theories, but it does happen and it's sublime.
     
  3. As color perception is a function of the photo receptor wall angles and there are no obvious external changes in anadromous fish eyes in freshwater I would strongly doubt any big change in steelhead vision while in freshwater.

    And, since steelhead see the "visible spectrum" as well as UV, I suspect their ability to see any given color has nothing to do with the likelihood of a take. I can believe their are lots of different factors determining whether they take or not and presentation is at the very top of the list...
    art
     
  4. First, a mini-lesson on fish color vision. White light, the light produced by the sun, is a mix of wavelengths of electromagnetic radiation = energy. When white light hits any object the different wavelengths of light may a) pass through it (transmitted), b) change its direction (reflected), or c) absorb its energy. The fate of any specific wavelength interacting with any specific object depends on the behavior of the electrons on the molecules at the surface of the object.

    Most fishes have good color vision; the exceptions are primarily nocturnal and deep-sea fishes that have abundant rods to discriminate shapes and grays in low light. Color vision requires much higher light intensity to detect a signal. Most fish species have several types of cones, each with a different visual pigment and these cones including more structural diversity than seen in mammals (twin cones, double cones). Different visual pigments, because of differences in the structure of their component atoms, absorb different wavelengths of light. If you compare several fish species, the wavelengths absorbed by the visual pigments of each species make sense in light of the spectra of light in their environment.

    The key to color vision is to have cones that are sensitive to the dominant wavelength in the environment and to have other cones that are sensitive to wavelengths that are offset from the dominant wavelength. You want to be able to detect the background (the dominant wavelength) and reflected wavelengths that contrast with the dominant wavelength. For example, in the open ocean, the dominant wavelength is blue because it penetrates the farthest is water. This is why open ocean waters are blue, the sky is blue, ice in glaciers is blue - these wavelengths travel the farthest and are the most likely to be scattered into your eye. Water molecules themselves absorb red wavelengths in just the first 10 - 20 feet, green after 60 - 70 feet or so. [If you cut yourself at 20', your blood looks green as there is no red light available to bounce off the hemoglobin.] In the open ocean and low productivity freshwater habitats (oligotrophic) there is little in the water, except water molecules, to interact with light. In coastal waters and high-productivity freshwater habitats (eutrophic waters), dissolved organic compounds (gelbstoff, in German) combine with water to absorb red (the water) and blue (the organics) wavelengths and green is the dominant wavelength. In waters that run through swamps (tea stained or "black-water"), dissolved tannins absorb greens and the dominant wavelengths are the reds, but they don't penetrate far because they are being absorbed by the water molecules. Some fishes that evolved in these tannin-dominanted waters have visual pigments that can detect the infra-red.

    Onto the question of salmonids. Salmonids have three visual pigments in various cones: blue, green, red. Behavioral experiments show that these fish can be trained to respond to signals of specific colors (wavelengths), indicating that they detect and interpret color much as we do. Accessory proteins bound to the light-absorbing pigments vary between freshwater and saltwater phases of the life cycle. As juveniles in freshwater, these accessory pigments that bind to the main visual pigments subtly shift the absorbances toward the green. Juveniles also appear to possess UV sensitive cones that are lost in adults [Ontogeny of ultraviolet-sensitive cones in the retina of rainbow trout (Oncorhynchus mykiss). by Allison WT, Dann SG, Helvik JV, Bradley C, Moyer HD, Hawryshyn CW. in J Comp Neurol. 2003 Jun 30;461(3):294-306. This is interesting in light of the recent marketing interest in UV reflecting coatings and materials for salmon fishing. This wouldn't be a case of marketing hype trumping science, would it?]. As salmonids head to the ocean, part of the process of smoltification involves a turnover of these accessory proteins with their replacements shifting absorbances subtly toward the blue, consistent with the dominant light in their open ocean habitats. When the fish are migrating back to their natal rivers to spawn, these accessory pigments change back slightly to the green side of the spectrum. I would presume a steelhead that spawned successfully and headed back to sea would shift again, but I don't think that this has ever been tested.

    See also www.sexyloops.com/articles/whatsalmonidssee.shtml and www.sexyloops.com/articles/colourinthefisheseye.shtml

    Steve
     
  5. Uh Steve...what are you talking about man? That is not even english. English, please, english.
     
  6. ok, red good in fresh water but difficult to see in dirty water, right? so then what?
     
  7. Cabezon that is more than a mindful!

    What is important is how visible is a fly under the conditions. Colors fade out with decreasing light intensity in a very specific way. Remember ROY G BIV, like a rainbow or what you see when white light passes through a prism. Red Orange Yellow Green Blue Indigo Violet are the spectrum colors. As light diminishes the red is the first to fade out, then yellow, orange, green, blue, indigo and finally violet at the lower levels of illumination.

    Where the sun is in the sky is also a factor.

    Now add in the color of the water.

    Any color will work under certain conditions most favorable for that color.

    Then as mentioned presentation may be more important than any of the above!

    Throw in the fickle nature of a fish and add that to your mix and perfect all of the above and then when lady luck smiles a steelhead just may come along and eat your offering.

    To parahrase John Schewey, there is no magic fly for steelhead! If there were you wouldn't see the huge variation of patterns. It is having confidence in what you are using and in yourself to make a proper presentation where it needs to be presented.

    wet line Dave
     
  8. Nice info Steve.
     
  9. Cab, I bow to your wisdom . . . impressive, to say the least (and that is sincere!). From some 53-years of fly-rod in hand . . . .

    Done well with dark colors in low-light (believe it's the silhouette thing.).
    Done well with bright colors on Steelies in bright light (no clue as to why).
    Done well in general "matching what they're eating."
    I'm a firm believer in "you pick the fruit where you find the tree." Sometimes it makes no sense, but if fish hit it, I'll tie one on & keep it there as long as the fish spirit moves me . . .

    Oh, and purple is a most productive color in the Hanford Reach (must be Pasco Bulldog fans . . . or, bitter rivals. But it works.).
     
  10. I've talked to several fishery biologist over the years about steelhead "feeding" and each one has told me the same thing: Steelhead have digestive tracks that become inoperable when the make the change from saltwater to fresh water upon their return to their natal river systems. In other words, they cannot digest any food item they may ingest. This is why if you kill and then gut an adult steelhead caught in a river, you will find intact or very nearly intact organisms along with sticks etc. in their guts, which is very different than when you gut a resident trout where you will find some intact organisms (the ones it just ingested recently) along with a sort of sludge-the partially digested organisms.

    Each of these biologist also have told me that steelhead will at times ingest insects (as well as sticks, etc.) and at times bait fish, but that it is most likely a conditioned response (habit) developed from the time they were parr until they returned to the river as adults. In other words, they aren't feeding in the normal sense of the word because any food they might ingest is not going to be digested (at least for most subspecies of steelhead), so they aren't ingesting it for norishment. All this is a fancy way of saying that for all intensive purposes, steelhead don't feed when they return to the rivers as adults.

    This lack of feeding is one of the major differences between steelhead and resident rainbows. And I'm convinced is one of the major reasons steelheaders lack of trying to "match a hatch" or other food is a mystery to those who haven't fished for steelhead, or only occassionally fish for steelhead. Good thing steelhead are like this though, otherwise we woudn't have all those varied, colorful, and to some maddeningly difficult to tie (like is spey and dee flies, GP's, Ally's Shrimp, etc.) flies to toss out in the streamy water to entice a steelhead to grab on.
     
  11. 50% of the steelhead I've hooked in the last 3 years have taken an egg sucking wooly bugger. All winter fish. I fish it far less than 50% of the time.

    Why don't I fish it more? Flies catch steelheaders. Steelheaders catch steelhead.

    GoSox,
    cds
     
  12. Sorry I had to delve into some of the technical details, but it is a fascinating topic and has been studied extensively. There was a series on fish vision several years ago in one of the flyfishing mags.

    Here is how some of this information may be important to flyfishers, maybe less so to steelheaders specifically. Imagine that you are using a red chironomid and a black chironomid in a tandem setup. If you are fishing both in the top 10' of water, there will be wavelengths of red light available to bounce off the material on the first chironomid (and absorb all others) and it will look red to a trout. The materials on the other chironomid will absorb all the light hitting it and it will look black to a trout. Now imagine that you are at Dry Falls and you see that the fish are cruising in deep water, 20+ feet, and you either use a sinking line or a long leader to reach them. Now, there is no red light to be reflected off your "red" chironomid and it will look black, just like the other chironomid.

    Here is another example. The krill (euphausids) that are prime prey for resident salmonids have red pigments spots on the bottom side of their body. During the day, krill are typically deep enough that these spots will look black because there is no red light to reflect off them. When they migrate to the surface at night, there is not enough light energy for their predators to use their cones; as seen in rods, the pigments will look black as well.

    Under low light conditions, rods become the primary source of visual information and they do not detect color. Rods are what you are using at dusk when you can see objects with fuzzy outlines and no distinctive colors.

    Bottom line. Steelhead, especially in the shallow waters that flyfishers are sampling, should see the colors of flies pretty much as you see them in the water. In the upper few feet of water, there should be enough light of all wavelengths. But if you are fishing deeper, reds will be lost first. Also, contrasting colors (blues and reds, greens and yellows) are very distinctive because they stimulate different populations of cones.

    One of the more interesting aspects of color and steelhead fishing is the effectiveness of purple. Purple is actually a rare color in the real world. Yet, we know that it is works in purple perils, purple egg-sucking leaches, etc. Getting into the mind of a steelhead when it is back in freshwater is not easy and I think that you are likely to find considerable fish to fish and river system to river system variation in what attracts fish and triggers strikes.

    Steve
     
  13. Hi Steve,

    I am afraid those information above are a bit out of date, see the newer study and their criticism to the (Allison et. al 2003) in
    Journal of Experimental Biology 210, 4123-4135 (2007) Christiana L. Cheng and IƱigo Novales Flamarique* and also Nature. 2004 Mar 18;428(6980):279. Cheng CL, Novales Flamarique I.

    Briefly, I think color perception in steelhead maybe important in fly design,well, because the rational behind it is to design a color that steelhead can see well underwater. Is this right? Not quite IMO...steelhead can see your fly well, but they can give you a big rejection response. All the good hook up (regardless steelhead or trout) need two factors to work together, 1) see well and 2) accept the fly (food / enemy).

    That is the reason that sometimes a more subtle color blend into the background will work better than the showy color, smaller flies will out fish the bigger flies... because more showy color may get more rejections in certain conditions...

    I have heard about steelhead rise for leaves, branches or insects... if the goal is to match the fly to those obstacles (presumely people here are more interested in taking a steelhead with a dry fly), you don't really need to care about the UV vision of the steelhead, because most of the dry leaves, branches and insects don't have UV reflectance. The regular non-UV elk hair caddis will look just like real October caddis which don't have too much UV reflectance on their wings either.

    When seeing those articles of visual stimulus in lure design and fishing, I always wondering why there is one particular perspective has been overlooked? That is the background coloration. (Color perception is not only about visual stimulus, but also the neuron process in the brain.) The background color will heavily influence the object color that being perceived by the receiver. Presumely fish are looking up from the river bottom, fly color will change depends on the shift of background colors. Fly under the bright bluebird sky will look very different than the fly under heavy clouded weather.

    The solution?
    I think I will just listen to the old timers about what fly to use in what river condition and forget about the vision theory...
     
  14. Thanks Yuhina. I haven't looked into the specifics of color vision, especially UV in a while.

    Background color should matter quite a bit as it is the contrast between the fly and the background that makes a fly stand out. Many mayflies and stonefly nymphs are two-toned with a darker dorsal color to blend into the darker bottom when viewed from above and a lighter ventral color to blend into the brighter surface conditions when viewed from below, a phenomenon known as countershading. Because we tie generally "in the round" these distinctions in color do not play as big a role in fly design as they might. Layering or weaving of materials can produce these two-tone effects.

    Steve
     
  15. They see all colors, but especially the big 3: black, black, and black.
     
  16. Why we have both kinds; Country and Western.

    I tie flies in colors other than Black. If I use them I always go back through with black., unless I'm fishing with someone else. Then I make sure one of us is using black.

    ITWT,
    cds
     

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