Relationships between fish abundance and diversity and stream pH and alkalinity were assessed to evaluate potential impacts of acidic precipitation on fish assemblages of southern Appalachian Mountain headwater streams. Data were obtained from first- and third-order reaches of 12 stream systems during spring and fall 1983 and spring 1984. Assemblages exhibited low diversity and typically had low biomass. All streams were slightly acidic (mean pH = 6.62; range 6.25-7.00) and very poorly buffered (mean total alkalinity = 58 /µeq/liter; range 16-33), indicating extreme chemical sensitivity to acidification. However, statistically significant relationships between fish biomass or diversity and stream sensitivity were not consistently detected. The absence of such relationships suggests that acidification probably has not had a substantial impact on fish populations in headwater streams of the southern Appalachian Mountains.
