Summer food habits and prey taxa and size electivity of age-0 white bass in a South-Central Nebraska irrigation reservoir

Abstract

Understanding consumption patterns and preferences of particular life stages for fish species can clarify potential dietary overlap and identify energy flow within aquatic communities. Age-0 white bass (Morone chrysops) have been documented to consume a variety of prey items and zooplankton are a common occurrence. The importance of particular zooplankton taxa and available sizes will likely impact prey selectivity, which is not understood for age-0 white bass. The objectives of this study were to evaluate food habits, prey electivity, and size selectivity of age-0 white bass in an irrigation reservoir from July to September 2015 and 2016. By number, age-0 white bass consumed mostly zooplankton from July to September. Consumption of fish become an important component of the diet for 22% of fish starting at 80 mm TL. Calanoida were the primary zooplankton taxa consumed and selected for by age-0 white bass. In relation to other zooplankton taxa, Calanoida were one of the most abundant taxa groups available and age-0 white bass displayed size selective feeding by consuming the larger Calanoida available in the environment. While Calanoida are not the largest taxa available, their high density appears to result in higher consumption by age-0 white bass compared to other available taxa.