The effect of road crossings on fish movements in small Etowah basin streams

Abstract

Increased road construction associated with urbanization may result in fragmentation and loss of fish populations in streams. In this study, we documented frequency of movement of fishes through three separate types of road-crossings (clear-span bridges, box culverts, and tube culverts) in six small streams using mark-recapture sampling. Upstream movement between areas separated by either box or tube culverts was lower than upstream movement between similar areas not separated by a road crossing. Downstream movement between areas separated by box culverts was also lower than downstream movement between areas without obstructions. Upstream and downstream movement between areas separated by clear-span bridges was generally similar to patterns of movement between areas not separated by a road crossing. Our results indicate that culverts may limit, to some degree, movements of fishes in small streams.