NEAFWA 2018

AUTHORS: Alejandro Molina-Moctezuma, University of Maine, Department of Wildlife, Fisheries, and Conservation Biology; Joseph Zydlewski, U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, University of Maine, University of Maine, Department of Wildlife, Fisheries, and Conservation Biology

ABSTRACT. Quantifying the downstream survival of migrating fish past hydropower dams is critical for conservation efforts. Regulatory agencies often require assessment of fish survival using telemetry as a condition of operation. Failure to meet a survival threshold (i.e. standard) may result in required operational or structural changes at a facility, as well as continued assessment. Establishing a standard, as well as interpretation of results of survival analyses, can be a point of contention between agencies and dam owners. There are inherent statistical trade-offs when choosing a standard value, the method for interpretation (e.g. use of point estimate v. inclusion within confidence intervals), and the number of years a certain criteria must be satisfied consecutively. In addressing this we make a distinction between a biological threshold (the real world performance goal) and a statistical threshold (a function of biological threshold, sample size, interpretation method, and years of consecutive evaluation). We have developed a web-based tool that explores and graphically compared these thresholds as a tool for managers and dam owners involved in the assessment of fish survival.