EXTENDED ABSTRACT ONLY-DO NOT CITE

Environmental stressors such as contaminants can cause a variety of biological responses in fish ranging from the biomolecular and biochemical to population and community-level effects. To assess fish health, the bioindicators technique utilizes a suite of biological responses both as integrators of stress effects and as sensitive response (early-warning) indicators of existing and past environmental conditions (Adams 1990). Short-term indicators, such as biomolecular and biochemical responses, and longer-term ecologically relevant indicators, such as population and community responses, are included in this approach to provide measurement endpoints that can be used in environmental management or in the regulatory decision and ecological risk assessment (ERA) process. Biomarkers of environmental stress at lower levels of biological organization such as the mixed function oxidase (MFO) enzymes and DNA integrity provide direct evidence of exposure to stressors while intermediate-level responses such as histopathological, bioenergetic, immunological, and reproductive changes can help predict stress effects at the individual, population, and community levels. Responses at the lower levels of biological organization have the primary advantage of being relatively sensitive (short-term response) to stressors thus serving as early warning indicators of impaired fish health. Conversely, responses at higher levels of organization (populations, communities) are relatively insensitive (long-term response) to stressors but have higher ecological relevance and are therefore more directly applicable to the ERA process and for addressing environmental management and regulatory issues (Fig. 1). Biomarkers, however, cannot be considered useful bioindicators of fish health unless they are causally linked to 7 ecologically relevant responses such as population or community-level endpoint