Rainy Day At The Flint

We went out Friday morning to do transects at the Flint River site. The river was way low, and we worked in intermittent rain with thunder rolling to our south. We found fewer darters than usual, even with low water, because much of the riffle site is now covered with thick wads of green filamentous algae. My working theory is that this stuff blocks water flow at the bottom of the stream, where darters live and catch food, and the fish leave rather than hang around with this obstruction. The stuff is disgusting. We found the species pretty well separated from each other: the black snubnoses were in shallow, slightly flowing water and in some of the emergent vegation; stripetails were pretty much in that niche, and somewhat out in deeper water; bandeds were in their typical midstream fast water sites; and redlines were largely absent from the main channel, but were very common in an isolated side channel with fast shallow water over cobble and boulder substrate. This time we netted no rainbows or greensides, which was odd. I'm also confident now that the occasional Cyprinella shiners we net are Spotfin Shiners, not really a surprise. In the picture below are Eric, Brian and Alex as we prepare to hit the water. You can see some of the algae crud as streaks in the center of the river.