Side-Scan Sonar and White Sturgeon Acipenser transmontanus in the Snake River

Hydroacoustics are effective and non-invasive sampling methods to assess fish populations.  Side-scan sonar (SSS) is mobile imaging sonar that provides the ability to quickly survey large areas and has many practical applications to inland fisheries research, including detection and identification of large fishes (e.g., sturgeons).  We conducted a pilot survey in a 15 kilometer reach in the middle Snake River, ID to evaluate SSS as a potential method to assess WS abundance.  Using a N-Mixture model, within a Bayesian framework, we modeled replicate count data from 10 sites to estimate WS abundance.  Our median estimate of WS greater than 1 m in length (131; 95 % credible interval 120-150) is thought to be reasonable based on prior mark-recapture assessments.  A comparative study between SSS and traditional mark-recapture assessment will be conducted in 2016.  This pilot evaluation illustrates the potential of using SSS as a non-invasive method to quickly assess WS populations.