The Influence of Turbidity on Prey Consumption in the Tessellated Darter

Abstract

AbstractIncreased turbidity and the resulting decreases in water clarity have been shown to alter fish foraging behaviors in potentially detrimental ways. Given the ecological importance of darters of the genus Etheostoma and their dependence on visual cues, we examined the impact of a range of turbidity levels (3.5, 6, 10, 20, 22, and 25 nephelometric turbidity units [NTU]) on the number of prey consumed by the Tessellated Darter Etheostoma olmstedi. While a study of the Fountain Darter E. fonticola found that turbidity affected prey consumption at slightly elevated levels (≥8.7 NTU), we found no significant differences in consumption by the Tessellated Darter across turbidity levels. While there may be intragenus variation in the use of olfactory cues, another and perhaps more likely explanation is the difference in long‐term exposure to a range of turbidities. The Fountain Darter is endemic to clear, primarily spring‐fed rivers, whereas the Tessellated Darter is, comparatively speaking, a generalist that inhabits a variety of water‐clarity conditions. These data contribute to a growing body of literature highlighting the complex influences of turbidity on aquatic communities and speak to the conservation challenges associated with this ubiquitous environmental issue.Received April 26, 2016; accepted January 9, 2017 Published online March 30, 2017