Trophic Ecology of Banded Sculpin (Cottus carolinae) Across a Stream Size Gradient in Tennessee

Banded Sculpin (Cottus carolinae) is a widely distributed benthic fish that inhabits first- through eighth-order streams. The goal of this study was to assess “landscape-scale” trophic ecology of Banded Sculpin in the Roaring River Basin in north-central Tennessee. Objectives included: (1) assessing the relationship between fish size (total length, mm) and diet breadth; (2) quantifying change in diet as flows declined from spring to summer; and (3) testing for changes in diet across second- to fifth-order streams. We collected 196 Banded Sculpin from four sampling sites distributed across the Roaring River Basin in northcentral Tennessee. Stomach contents were identified to the lowest practical taxonomic levels and diet niche breadth was calculated for each individual. We found larger fish had broader diet niches, niche breadth was constrained as flows declined, and niche breadth was greatest in smaller streams. Our study represents the most comprehensive analysis of Banded Sculpin diet and suggests that stream environmental templates regulate trophic ecology across aquatic landscapes. Specifically, headwater streams promote broader diet niche breadth, but these streams are sensitive to periods of low flow during which diet niche breadth is constrained. In larger streams flow is more stable, but diet niche breadth is consistently narrower.