Fish Activity and Water Temps   6 comments

OK all you biologists out there. I have a theory.

The graph below shows water temps at a monitoring station in Black Earth Creek, with the last data point being taken at 8:00am. In my opinion the ideal water temp for trout activity is in the range between 59-degrees and 64-degrees F. The temp of the water goes through that range twice a day in the spring and summer.

Overnight and early this morning it has dropped from the high 60’s and has come down through that range. Later today it will climb again and will go up through that range.


Stream Temps on BEC at Black Earth, WI


So, my theory: Trout are more likely to actively feed as the temps increase through the ideal temp range.

Counter-theories would be that…


  1. Trout are more likely to actively feed as the temps decrease through the ideal temp range, or
  2. As long as the water is within the ideal temp range, Trout don’t care if it’s increasing or decreasing, they’re equally active in either scenario.


Does anybody out there have ideas or perhaps even data to support any of these theories?

6 responses to “Fish Activity and Water Temps

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  1. According to the weather forecast this weekend…will it be a good weekend for fishing?!

    • It will be interesting. Saturday looks gorgeous. Sunday, I wouldn’t bother fishing past 10am. Looks like it will be a scorcher! Monday looks nice as well. We could use the rain that’s forecast, that’s for sure!


  2. I’m through with trout fishing. I’m on to the next great thing. (pause) Okay, I’m back, I just missed it too much.

    Why can’t we be in an extremely slow warming trend from 58 degrees that last 8 weeks?

    • So you’re suggesting that an increase in temperature within the prime range is ideal?

      Glad to hear you haven’t given up on trout fishing. I plan to stick with it for a few more years at least.


  3. I just found this blog and I’m liking what I’m reading. I am new to this area and am just meeting many of these streams. Thanks for all of the posts.

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