Assessing impacts of power plants on fish populations: A general strategy

Environmental impact statements are often characterized by extraneous data collection, irrelevant statistical procedures, misapplied models and concomitant ambiguity in conclusions. Impact assessment is difficult but when explicit objectives are not stated and specific tasks are not linked to these objectives, assessment becomes impossible. We emphasize a flexible approach that can be adapted to site-specific requirements. The strategy consists of six steps: (1) Conceptualization of the ecosystem, (2) design and execution of pilot studies, (3) refinement of conceptualization, (4) design of a study plan, (5) execution of the study plan and (6) evaluation of impact. Development of a conceptual model leads to specification of testable hypotheses directly linked to the objectives of impact assessment. Deterministic and stochastic simulation modeling can be coupled effectively with traditional statistical methods to reduce the probability of decisions which impose unnecessary risks on the environment or costs to industry.