Changes in Fish Communities and Trout Management in Response to Acidification of Streams in Pennsylvania

Abstract

A major loss of fisheries in Pennsylvania resulting from acidic deposition has occurred in small headwater streams that support primarily brook trout, Salvelinus fontinalis. As streams become more acidic, fish species richness declines until only brook trout or, in severe instances, no fish remain. Among low pH streams, species richness increases downstream from the headwaters because water quality improves. Toxic conditions frequently occur during high stream discharge when pH declines rapidly and dissolved aluminum increases. Continued acidification has resulted in changes in management of nearly 1,300 km of stocked trout streams. The total length of trout streams adversely influenced by acid deposition is greater than 3,000 km.