Fish Population Responses to Chronic and Acute Pollution: The Influence of Life History Strategies

We have developed a simulation model to estimate pollution effects on economically important estuarine-dependent fish populations. Traditionally, pollution studies have focused upon impacts on individual organisms; however, wise management of marine resources depends upon an understanding of dynamics at the population level. As a required first step toward conducting relevant pollution studies, we have compiled available life history data on eight species (14 spatial-temporal stocks), concentrating on age-specific rates of growth, survival, and fecundity. Leslie matrix models of species population dynamics were used to predict pollutant impacts—mediate through changes in 1st-year survival. On average, and without compensation, these modelled stocks respond to a one-time-50% reduction in first-year survival by taking ten years to equilibrate at 88% of their preimpact abundance. Our synthesis of the data included a search for derived (standardized) population parameters to evaluate differences in susceptibility among and within fish populations to pollutant stresses. We demonstrated that knowledge of a species’ age-specific fecundity pattern provides additional predictive power of its response to pollution perturbation.