Evaluation of Behavioral Cues for Guiding Silver American Eel at Hydro Projects

During annual spawning migrations from freshwater to the marine environment, silver eels may experience high mortality rates if they pass through turbines at one or more hydro projects.  Consequently, providing safe downstream passage for silver eels at projects in North America and Europe is a priority for fisheries managers and project owners.  In response to this need, the collaboratively-funded Eel Passage Research Center (EPRC) was established by EPRI and U.S. and Canadian utilities and resource agencies to investigate technologies that can be used to reduce turbine entrainment at large hydro projects on the St. Lawrence River.  As part of the EPRC's efforts, we completed a laboratory evaluation of behavioral cues designed to elicit avoidance reactions from silver eels and guide them towards a collection system.  This study included tests conducted in a large flume with an electrical guidance system (Smith-Root, Inc.) and the Flow Velocity Enhancement System (Natural Solutions LLC) to determine the ability of each stimulus, alone and in combination, to repel and guide eels as they moved downstream.  The methods and results of these studies will be presented and the potential of each technology to facilitate safe downstream passage of eels at hydro projects will be discussed.