Assessment and Management of Fish Community Health in the Great Lakes: Synthesis and Recommendations

Our objective was to provide a perspective on fish community health to serve as a conceptual framework for assessing the effects of toxic chemicals and other anthropogenic influences on fish communities in the Great Lakes. We discuss the hierarchical structure and homeostatic mechanisms of aquatic ecosystems, and describe a general ecosystem stress syndrome (GESS) that characterizes patterns of ecosystem response in terms of alarm, resistance, and exhaustion. Anthropogenic stressors operate at various levels within the organizational hierarchy of aquatic ecosystems, and their effects are filtered and propagated throughout the system by physical, chemical, and biological processes. Determination of causal relationships between stressors and system responses has proven difficult because of the multiplicity of factors that influence system behavior. Methods employed for fish health investigations in the Great Lakes span molecular to ecosystem approaches, reflecting the diversity of stressors operating on the fish communities, but have tended to be applied within relatively narrow disciplinary perspectives. We perceive a need for broader perspectives and interdisciplinary investigation of the effects of toxic chemicals and other stressors. Attainment and maintenance of healthy fish communities, which we define as relatively stable, self-sustaining assemblages of fishes providing sustained economic, social, aesthetic, and ecological benefits, requires an ecosystem-based fisheries management strategy. The strategy must incorporate the integral roles of humans and other terrestrial species in the Great Lakes ecosystem in recognition of feed-back mechanisms involving resource utilization and waste and material inputs, thereby incorporating health concerns for all high risk populations including humans. We recommend adoption of a field-oriented epidemiological approach for monitoring and assessment of fish community health, supported by transdisciplinary investigative teams for ecosystem problems requiring diagnostic and remedial activities. We suggest that Areas of Concern under Annex 2 of the 1978 Great Lakes Water Quality Agreement be used as sites for comparative management experiments involving deliberate manipulation of ecosystem processes, not only to rehabilitate these areas, but also to improve understanding of the structural and functional properties of these systems, and to provide feedback for adjustment of the selected management options.