cutthroat or rainbow?

Discussion in 'Fly Fishing Forum' started by Rory McMahon, Sep 13, 2007.

  1. This seems like a little bit of a noob question, i realized the other day that I have really never learned how to tell the difference between a rainbow and cutthroat(coastal, not westslope). Ive just always known what the fishery held, either rainbow or cutthroat, and if it held both i would just look for the slash mark, if there was a slash, it would be a cutt, if there wasn't, i i would think it was a rainbow. I know that not all cutthroat have slash marks, so im asking other ways to tell them apart, i figured you can tell by the coloring, or if there's any other ways to tell them apart.
  2. As far as cosmetics Coastal Cutties usually have denser spotting.

    But the tried and true is the following two:

    1. Cutts have different mouths. The mouth of the cutthroat extends past the eye (Which happens to be one of the differences between smallmouth and largemouth bass btw).

    2. Cutthroat have teeth on their tongue whereas rainbows do not.
  3. I don't think I've ever seen a cutthroat, even in salt water, that completely lacked the slash marks. Sometimes they are only a very pale orange or pink in color, scarcely noticeable but there if you look carefully. The basibranchial (formerly hyoid) teeth form a small triangular patch at the back of the tongue and can easily be felt with the fingertip. These teeth do occur in cutthroat/rainbow hybrids as well but are usually reduced.

    Colors and spotting patterns are not always absolute indicators since both may vary considerably but, generally speaking, the cutthroat will have more and finer spots, covering more of its body, sometimes even occuring at the base of the pelvic fins. Even in salt water, cutthroat show a light brassy coloration that gradually increases as sexual maturity approaches. It becomes quite noticeable in mature fish by the time they have entered the rivers.
  4. cutts have longer mouths, more and denser spots, and usually no red stripe.

    note how there are spots everywhere including the face and gill plates also note the long mouth... Heres another fish look at its mouth (I think this is a hen so the mouth is a bit smaller)
    again look at the spots
    Heres a rainbow, look at the shorter mouth and note how the spots get very irregular forward of the gill
  5. NOT a stupid question. This is turning into a great thread.
    Based on what we think we know what species is this trout?


  6. Okay, I'll ring in....

    A Redband Trout--a (sub?)species of rainbow. I hear from Preston and others that the redbands, such as those found in the Yakima, will have the slash marks, though they are not cutthroat. Often mistaken for "cuttbows."
  7. I second pcknshvl's identification. I know a guide that mentioned the same thing.
  8. Resident rainbows on the Yukon delta often have very pronounced red slashes on their jaw, and their mouths extend past the eye - much larger mouths than their southern cousins. Dense spots cover every inch, even inside of the eye. Not always easy to develop simple criteria to separate closely related species...
  9. To know for sure, forget coloration and check for the teeth on the tongue (vomerine teeth): cutthroats have em; rainbows don't.
  10. That fish didn't have tongue.
  11. In vertebrates, the vomerine bone is a bone in the skull; in fish it is located in what we would think of as the roof of the mouth. I believe what you are referring to are basibranchial teeth which were formerly known as hyoid teeth and which can be found in a small triangular patch toward the back of the cutthroat's tongue.
  12. thanks for all your answers, this brings me to a similar question. Is there a way to tell a steelhead/salmon smolt from a trout.
  13. Correct me if I'm wrong here, but I thought there technically isn't a difference between a steelhead smolt and a rainbow trout because they're the same thing only one of them is anadromous.
  14. The scientific articles I have read suggest that rainbows can have steelhead offspring and vice versa. Assuming that is true, I wonder why the mid-Columbia steelhead recovery doesn't provide protection to rainbow trout?
  15. Yep, they're the same species. Same scientific name and everything.
  16. From here on out it gets kinda tricky because you are talking about different populations of rainbows and steelheads. Some populations are more likely to be sea run than others that maybe isolated from the ocean somehow or maybe there just isn't a need to go to the sea to find food.
    In the case of steelhead nature provides genetic insurance by selecting a few (or more) of them to residualize. The same probably happens with resident rainbow populations wherein a few of them go out to sea, maybe even make their spawning run up a different stream.
    That's how it seems to me anyways.
  17. Yes, they can be told apart, but not easily. Chum and pink fry and most chinook are not a problem since they leave the rivers at a very small size, almost as soon as they swim up from the gravel. In the case of Chinook, ocean-type fish usually have left the by the end of the summer of their first year, stream-type Chinook normally spend their first year in fresh water before rapidly migrating to salt water. Steelhead (rainbow/steelhead since, although populations may differ, either may choose to adopt an anadromous lifestyle), coho salmon and cutthroat parr spend at least a year and sometimes more in fresh water before out-migrating.

    There is absolutely no way to differentiate between a rainbow/steelhead parr which will choose anadromy as opposed to residency. Only when the parr begins to smoltify do differences become apparent. Smolts take on a decided silvery appearance with dark blue or green backs and lose their parr marks. This is the outward indication of the inner systemic changes that are taking place which will allow the fish to survive in a salt water environment and occurs in the late winter and spring before its out-migration.

    Coho remain in fresh water for one to two years and bear some resemblance to cutthroat parr. The most easily distinguished difference being the black leading edge of the coho's anal fin. I found an book a while back; Field Identification of Coastal Juvenile Salmonids by Pollard, Hartman, Groot and Edgell, from Harbour Publishing. It is lavishly illustrated with watercolor paintings and photographs.
  18. Is there a specific sub-species of rainbows that have the red slash? I've caught some on in Connecticut that looked a lot like the cutt-bows I used to catch in MT but cutties are not found in New England.......
  19. Robert Behnke recognizes two major subspecies of rainbow/steelhead. The coastal subspecies, Oncorhynchus mykiss irideus, which he calls the Coastal Rainbow Trout, and the Redband Trout of the Columbia Basin, O. m. gairdneri (there are also a number of other subspecies whose evolutionary paths have led to characteristics which differ from these two major divisions). The Redband Trout of the Columbia River Basin sometimes show a yellow to pale-orange slash similar to the red marking of of the cutthroat. But, so far as I know, no rainbow subspecies consistently shows any such marking. Is it possible that the Connecticut hatchery is using hybrid cutthroat/rainbow stock?
  20. See previous post - Yukon delta (e.g. Kanektok) rainbows very often have the red slash. I have some photos, but I will need to scan them and figure out how to post them.

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