The Stream Doctor

July 26th, 2004

Email YOUR Questions directly to the Stream Doctor. This is your opportunity to get an experts professional opinion on anything stream related.

Q. I primarily fish two Utah rivers - the Provo and the Green. On my last outing on the Provo, I caught several large brown trout. While handling these trout I noticed two things about their markings which contrast to the browns I have caught on the Green. First, the Provo browns seemed to be a very faded color of green. Second, these browns seemed to have scarlike markings all over their body.

The markings could be a result of the browns being frequently snagged due to the large amount of nymph fishing done on the Provo. I also do most of my winter and fall fishing on the Provo, while devoting the summer to the Green. Perhaps this could have something to do with the coloration differences. Thanks.

A. I called Dr. Robert Behnke at Colorado State U. to see if he had any experience with the trout from the Provo and Green. He didn't, specifically, but suggested that color variations can be influenced by various factors including both stocking history and heredity. Brown trout stocks originated in both Germany and Scotland, but you would have to study the stocking and rearing records of the strains planted in your two rivers to see of the color differences might be traced to different stocks. Environmental factors can also influence color variations; the old "nature vs nurture" argument. Hatchery folks will tell you that diet can affect color; also, hatchery fish tend to be lighter in color than wild fish. That's about the best I can come up with on the color variations you've observed.

As to the scarlike markings, neither Bob nor I think it could have anything to do with nymph fishing. It is highly unlikely that accidental snagging by nymphs could be as extensive as you indicate. A more likely source would be scarring by rocks tumbled downstream during high flow periods, and even this is unusual.

If you have a question, please feel free to contact me.
~ C. E. (Bert) Cushing, aka Streamdoctor
105 W. Cherokee Dr.
Estes Park, CO 80517
Phone: 970-577-1584

The 'Stream Doctor' is a retired professional stream ecologist and author, now living in the West and spending way too much time fly-fishing. You are invited to submit questions relating to anything stream related directly to him for use in this Q & A Feature at

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