Sunday, November 28, 2010

Estill Fork Had Higher Water, Interesting Darters

Of course, we went to Estill Fork to find darters and we did. After some rain earlier in the week the river was at a normal level, or even more so, with some water running over the low bridge. So we modified our sampling technique from September. We made eight transects instead of sixteen, each of about 15 meters, and took depth and flow measurements at 1 meter intervals from bank to bank. Most of the flow measurements were well over the zeros we found last time, and as a measure of that much of the emergent vegetation was scoured out.

We didn't net any blotchside logperch this time, but we did find greensides in the deeper, faster flows where you'd expect them and nowhere else. The new species this time was blueside darters, Etheostoma jessiae, found in greenside habitat as might be expected. Both fantails and stripetails were more common this time, too. The tennessee snubnoses are the generalist in this assemblage. We found them pretty much everywhere along transects, from deep, still water to shallow, flowing water and variations in between. Rainbows, the other common species, tended to be in shallow, flowing water.

On question I have is why there aren't banded darters at this site. They're present several miles downstream at the Baptist church site, but I've never, ever seen one at our study site. The major difference between the two sites is that the downstream site is rockier, and the upstream site substrate is largely sand and gravel. And that might be it.

Here's a view of the stretch of stream we were working, with Brian and Jeremy looking at a data sheet.
Here's a broader view of the same scene, with the whole crew: Robert, Alex, Brian and Jeremy.

And finally, Jeremy, Robert and Brian poking around in a seine haul trying to pick out darters while I'm holding the other end of the seine and taking a picture.

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