Acid Rain, Catchment Characteristics and Fishery Status

In this paper data on lake chemistry and fishery status in the Sorlandet area of South Norway are examined for relationships between acid inputs, water composition and fishery status. The concept of the “effective reactivity” of a catchment is introduced to enable comparisons to be made between like lakes. It is found that the effective catchment reactivity is a much better predictor of fishery status than is acid input to these catchments. The factors underlying these relationships are discussed as is the possibility that acid deposition has changed the reactivity of these catchments in recent decades. Proposals are made for resolving some of the questions raised.