Degree-day accumulation influences annual variability in growth of age-0 walleye

Authors

Christopher S. Uphoff, University of Nebraska at KearneyFollow
Casey W. Schoenebeck, University of Nebraska at KearneyFollow
W. Wyatt Hoback, University of Nebraska at KearneyFollow
Keith D. Koupal, Nebraska Game and Parks Commission, KearneyFollow
Kevin L. Pope, University of Nebraska-LincolnFollow

Date of this Version

2013

Citation

Fisheries Research 147 (2013) 394– 398; http://dx.doi.org/10.1016/j.fishres.2013.05.010

Comments

US government work

Abstract

The growth of age-0 fishes influences survival, especially in temperate regions where size-dependent over-winter mortality can be substantial. Additional benefits of earlier maturation and greater fecundity may exist for faster growing individuals. This study correlated prey densities, growing-degree days, water-surface elevation, turbidity, and chlorophyll a with age-0 walleye Sander vitreus growth in a south-central Nebraska irrigation reservoir. Growth of age-0 walleye was variable between 2003 and 2011, with mean lengths ranging from 128 to 231 mm by fall (September 30th–October 15th). A set of a priori candidate models were used to assess the relative support of explanatory variables using Akaike’s information criterion (AIC). A temperature model using the growing degree-days metric was the best supported model, describing 65% of the variability in annual mean lengths of age-0 walleye. The second and third best supported models included the variables chlorophyll a (r²= 0.49) and larval freshwater drum density(r²= 0.45), respectively. There have been mixed results concerning the importance of temperature effects on growth of age-0 walleye. This study supports the hypothesis that temperature is the most important predictor of age-0 walleye growth near the southwestern limits of its natural range.