Sample Size and Effort Requirements to Estimate Species Richness and Changes in Relative Abundance When Monitoring Habitat Rehabilitation Activities in the Kootenai River, Idaho

The Kootenai Tribe of Idaho has been actively rehabilitating habitat in the Kootenai River and portions of its floodplain.  As such, managers of the Kootenai River require information on sampling designs that can be used to monitor the distribution and occurrence of fishes.  Detecting changes in abundance is important for evaluating the response of populations to management actions.  Information on the number of samples required to estimate species richness and the amount of effort required to detect changes in abundance are valuable for monitoring various management activities in the Kootenai River, including habitat rehabilitation. We sampled fishes during the summer of 2013 using boat-mounted electrofishing.  We simulated sampling using real data from 7 sites in the braided reach of the Kootenai River at various levels of sampling effort.  We estimated the probability of sampling 50, 75, and 100% of the total number of species detected in each site at various levels of sampling effort (i.e., number of reaches).  We evaluated sampling effort for each month from May-September.  We estimated the effort required to detect changes (i.e., 10, 25, or 50%) in relative abundance at different levels of statistical power (i.e., 50, 75, and 100%) for each species using random sampling.