Understanding the cumulative effects of stressors on fish populations using effects-based assessments

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My NSERC-related studies are testing hypotheses about the role that variation in fish reproductive life histories plays in species differences in sensitivity to environmental contamination. The interpretation of environmental impacts depends on the abilities of sentinel organisms to reflect local conditions and of the researchers to understand the relevance of changes. The dominant fish species in smaller streams and nearshore marine areas tend to be small-bodied species that do not follow the typical synchronous spring-spawning strategy common to Canadian fish species previously successfully used for monitoring. There have been no attempts to develop generalized models or a mechanistic understanding of species differences in sensitivity or the influence of differences in reproductive strategies and timing on the ability to detect impacts. We have developed the necessary databases, study sites and methodology to make significant advances in these areas. My long term objectives are to broaden the understanding of fish reproductive strategies, and to use this understanding to generate new designs and strategies for achieving environmental protection goals. This grant will examine the a) relationship between reproductive strategy and sensitivity to population-level impacts of contaminants, b) sensitivity of population fluctuations to environmental changes, and c) linking fish reproductive strategy with its potential for recovery from the long term consequences of exposure. Predictions are that fish with strategies involving multiple spawns per season will show reduced sensitivity to contaminants, will be more stable over time, and will recover more quickly than species that spawn only one time per year. Our studies are contributing baseline information on the reproduction of Canadian fishes and are contributing to new knowledge about fish species in developing countries. The program is leading the development of a new study designs, sampling approaches, guidance for interpretation and perspectives on ecosystem health. The results will lead to the development of better guidance for assessment projects in terms of species selection, sampling design and interpretation of results.