Effects of Light and Turbidity on Foraging Efficiency of Larval Walleye Sander Vitreus
Abstract (Summary)Varying levels of light and turbidity are common in the shallow habitats used by some fish species as nurseries. Light attenuation and reductions in reaction distance from suspended sediments are known to negatively affect foraging by adult and juvenile fishes, but the effects of these variables on larval fish have been mixed. Herein, I test the effects of environmentally relevant levels of light (0.5 and 15.0 ?mol .s-1.m-2) and turbidity (0, 10, 40, and 100 NTU) on foraging by larval walleye (Sander vitreus) when feeding on zooplankton. Ingested prey biomass was not significantly different as functions of light, turbidity, or their interaction (two-way ANOVA, ? = 0.05), although trends in consumption suggest that walleye larvae may forage more efficiently at high light. In addition, apparent foraging peaks at 40 NTU suggest that foraging by walleye larvae may be maximized at intermediate turbidity. Foraging rate was exceptionally reduced for these larval walleye compared to numerical consumption rates found in the literature, so any trends (or lack of trends) need to be assessed in this context. However, the results are consistent with studies reporting detrimental effects of light reduction, and enhanced feeding in the presence of turbidity.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:light turbidity foraging larvae fish
Date of Publication:01/01/2008