Effective Patch-Scale Electrical Exclusion of Fish and Invertebrates in the Benthos Across Water Conductivity Levels Using Adjustable Electrical Settings for the Streon Program

Small electrical fields are often used to manipulate stream-dwelling organisms from patches of stream benthos. However, traditionally used devices such as livestock fence chargers typically offer little to no control over the frequency, voltage, and duration of electrical pulses, which likely influence their effectiveness. Ensuring the consistent exclusion of large consumers among streams with different water conductivities requires knowledge of how key electrical variables interact with water conductivity to affect exclosure performance. A device that controls the pulse frequency, duration, and voltage of exclosure electrical fields was developed and assessed for use in the STReams Experimental Observatory Network (STREON), a continental-scale, open-access experimental program. Laboratory trials evaluated electrical exclosure effectiveness on small crayfish and fathead minnows in water with conductivities ranging over three orders of magnitude. Findings indicate that exclosures with high pulse frequency (10 Hz) can exclude consumers at even very low conductivities (~10 µS cm^-1) but that several electrical parameters should be adjusted to appropriately match field conditions. Once designed and distributed throughout the NEON network, the STREON electrical exclosures will be available for other research applications.