Factors Associated with Larval Freshwater Drum Annual Peak Density in a Nebraska Irrigation Reservoir

Authors

Brett T. Miller, University of Nebraska at Kearney
Brian C. Peterson, University of Nebraska KearneyFollow
Keith D. Koupal, Nebraska Game and Parks CommissionFollow
Casey W. Schoenebeck, University of Nebraska at KearneyFollow

Date of this Version

2020

Document Type

Article

Citation

The Prairie Naturalist 52:3-10; 2020

Abstract

Freshwater drum (Aplodinotus grunniens) represent one of the most widely distributed fish species in North America. Identifying biotic and abiotic factors that influence larval freshwater drum densities can improve understanding of early life history. Our objective was to investigate correlations between annual peak density of larval freshwater drum and combinations of five variables (chlorophyll a, growing degree days [GDD], reservoir discharge, turbidity, and cladoceran density) from a longterm (2003–2017) monitoring program in a Nebraska irrigation reservoir. Twenty-eight a priori candidate models were assessed to determine the relative support of explanatory variables associated with annual peak density of larval freshwater drum using Akaike’s information criterion. During the course of the study, larval freshwater drum annual peak densities ranged from <0.1 (±0.1 SE) to 4.5 (±0.8 SE) /m3 and variations were best explained by chlorophyll a (highest relative importance, 0.77). Chlorophyll a was positively associated with higher densities of larval freshwater drum. This study highlights the importance of chlorophyll a to larval freshwater drum annual peak densities and provides a greater understanding of freshwater drum early life history.