Darters in the Nolichucky River

The Nolichucky River is a large tributary of the French Broad River, flowing out of some of the highest elevation mountains in the Appalachians of Western North Carolina and into rolling countryside in East Tennessee. It is a really gorgeous area to conduct field work in, with pastoral farmland on the rolling hills framed by the mountainous backdrop. The Nolichucky River is also home to a diverse array of darters, a group of fish that I have developed a passion for during my time and training as an aquatic ecologist.

Gilt Darter, Percina evides, from the Nolichucky River

Banded Darter, Etheostoma zonale, from the Nolichucky River

I conducted field surveys of darters in tributaries of the Clinch River, to the west of the Nolichucky, as part of my M.S. research. My particular research interests are in how these small fish select and partition their habitat. These fish are particularly interesting for this kind of research because they are fairly territorial, with limited home ranges. Additionally, it is often easy to find three or more different species of darter living in very close proximity to each other.

An effective method of documenting the microhabitat utilized by darters is to conduct snorkel surveys. Swimmers will move upstream in a given reach, usually with a well-developed riffle-run or riffle-pool complex, and identify any of the darters they encounter. The darters will usually attempt to avoid the swimmer, but will just as often stand their ground, bravely staring down the giant interloper observing them.

Snubnose Darter, Etheostoma simoterum, defending his home 

The snorkelers will record the species of darter they encounter, marking the location of first observation. A crew following the swimmers will then assess the microhabitat in those locations, and communicate with the swimmers periodically to record the species found at each location.

This protocol for collecting high-resolution data on the habitat utilized by darters is pretty effective, and is fairly commonly employed in studies of darter ecology. However, this technique is limited by certain site conditions. Namely, high flows and turbid water will greatly impair the snorkelers' ability to effectively survey for darters and prevent the rest of the crew from finding the weighted flags marking the location of the darters. These high-flow, turbid conditions are very common to the Nolichucky River at many of the sites where access to the public is available. The issue now, then, is to develop a new method of assessing darter habitat utilization that does not rely so heavily on high visibility and low flows.