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.

Resetting the Clock: How a Reconnection Event Reshaped Cove Fish Assemblages in a Nebraska Reservoir

“…Zooplankton taxa, such as cladocerans and copepods, serve as valuable food resources for fish (Crandall et al 2003;Lemke et al 2017), and increased food resources may decrease interspecific competition and support a wider range of taxa. Chlorophyll a and total zooplankton densities declined in Harlan County Reservoir after the reconnection event in 2019 (Koupal et al 2020), but increases in zooplankton taxa that appear to be important for predator species (Miller et al 2019;Uphoff et al 2019) and their prey (Sullivan et al 2011a(Sullivan et al , 2011b have been anecdotally observed in intermittent coves and, most notably, disconnected coves (K. D. Koupal, unpublished data).…”

“…2020), but increases in zooplankton taxa that appear to be important for predator species (Miller et al. 2019; Uphoff et al. 2019) and their prey (Sullivan et al.…”