A modelling framework for analyzing anthropogenic stresses on brook trout (Salvelinus fontinalis) populations

Modelling provides a convenient and useful means of assessing the possible risks contaminant stresses pose for many populations. While abundance has traditionally been considered an appropriate modelling endpoint, and has been shown to work well at broad levels of aggregation, it is nonetheless deficient for analyzing the population-level risks posed by sublethal contaminant stresses. That is because abundance-based models fail to consider important changes in population size-structure brought about by many sublethal stressors. An individuals-based modelling framework incorporating the specifics of life-history information for brook trout (Salvelinus fontinalis) populations is discussed as an alternative to abundance models. The developed model is validated against field data and the projections produced by the Leslie-matrix-based approach, RAMAS. Comparisons suggest critical differences exist in the projections made by the two approaches because of the lack of size-structure data contained in the Leslie-matrix-based approach. As an example of how critical such differences can be, the potential consequences of sublethal toxaphene exposures on brook trout population abundance and size-structure are examined.