Use of a passive interrogation array to evaluate entrainment of endangered fish in an irrigation canal
Authors: David W. Speas, Kevin McAbee, Peter D. MacKinnon, Kevin R. Bestgen, Cameron W. Walford, Julie Stahli
Year: 2014 (xlvi)
Abstract
We investigated entrainment of endangered and non-listed native fish in the Green River Canal (Green River, UT) using passive integrated transponder technology during the 2013 and 2014 irrigation seasons. The Green River Canal is a 1.8 m3/s gravity-fed irrigation canal which operates annually during the months of April through November. Working with canal company officials, we constructed a solar-powered passive interrogation array (PIA) about 150 m below the canal intake gates in 2013 and a second system about 400 m below the gates in 2014. In 2013, 81% of all fish detected in the canal were Razorback Sucker, Xyrauchen texanus (499 individuals). Colorado pikeminnow, Ptychocheilus lucius and Flannelmouth Sucker, Catostomus latipinnis comprised 13% (77 individuals) and 5% (33 individuals) of all entrained fish, respectively. Three Bonytail, Gila elegans and a single Humpback Chub, Gila cyphawere also entrained. Peak rates of entrainment (up to 270 fish in a single day) were observed immediately following cessation of spring peak flows in July, at which point the canal diverted about half of the Green River discharge at times. Results from the 2014 irrigation season are forthcoming and will be presented. Entrainment rates of endangered fish in the Green River canal are significant and efforts are underway to reduce or eliminate entrainment most likely through exclusion structures. We will continue to monitor entrainment rates using PIAs following construction of exclusion structures.
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