Understanding the ecology of disease in Great Lakes fish populations

Disease may be an important factor affecting wild fish population dynamics in the Great Lakes, but a lack of information on the ecology of fish disease currently precludes the prediction of risks to fish populations. Here we propose a conceptual framework for conducting ecologically-oriented fish health research that addresses the inter-relationships among fish health, fish populations, and ecosystem dysfunction in the Great Lakes. The conceptual framework describes potential ways in which disease processes and the population-level impacts of disease may relate to ecosystem function, and suggests that functional ecosystems are more likely to be resilient with respect to disease events than dysfunctional ecosystems. We suggest that ecosystem- or population-level research on the ecology of fish disease is necessary to understand the relationships between ecosystem function and fish health, and to improve prediction of population-level effects of diseases on wild fish populations in the Great Lakes. Examples of how the framework can be used to generate research questions are provided using three disease models of current interest in the Great Lakes: thiamine deficiency complex, botulism, and bacterial kidney disease.