Marking Small Fish with Stains for Estimating Populations in Heming Lake, Manitoba

Abstract

For estimating populations of trout-perch, Percopsis omiscomaycus (Walbaum), by immersing fish in solutions of stains, Bismarck brown Y was superior to two other stains tested. It was satisfactory for periods of marking up to 1 week. Neutral red indicator can be used in marking experiments of less than 2 days' duration but Nile blue A faded rapidly and is not recommended for use in estimating populations. Using multiple and single census methods of estimating population size, the most reliable estimates of trout-perch greater than 46 mm in length were 711,451 (Schnabel) and 883,148 (Petersen), or in number per acre 1186–1472.