Effects of Floods on Brook Trout Populations in the Monongahela National Forest, West Virginia

Abstract

The objectives of this study were to describe the effects of the January and May 1996 floods on the stream habitat features, redds of brook trout Salvelinus fontinalis, and brook trout density in 14 headwater streams in the Monongahela National Forest, West Virginia. We measured stream habitat features, estimated wild brook trout density, and mapped brook trout redds in summer and fall 1995. We resurveyed trout redds in February 1996. In summer 1996 we remeasured habitat features and estimated brook trout density. The floods caused substantial movements of stream substrates. The numbers of riffles and pools increased, though their lengths decreased. Redds were scoured during the January 1996 flood. Few age-0 trout were found in summer 1996, and their density averaged about 98% less than the previous year. Age-1 and older trout also declined; their density in 1996 was about 84% less than the previous year. The effects of the floods on brook trout density were most severe in streams at higher elevations.