Development and Evaluation of a Population-Specific Bioenergetics Model for Muskellunge

Muskellunge Esox masquinongy are a popular sportfish with populations occurring across a latitudinal gradient that could drive local adaptation of metabolic and food consumption rates in order to maximize growth. Current bioenergetics modeling for muskellunge, and most other sportfish, does not account for these intra-species differences. We created models for five individual populations of muskellunge from varying latitudes and conducted simulations under differing thermal regimes to explore the influence of temperature on growth patterns. We also created a general range-wide model by pooling all populations. In simulation exercises, populations from high latitudes showed increased growth under a cool thermal regime while those from low latitudes grew faster in a warm thermal regime. However when compared to field data the population-specific models accounting for thermal adaptation showed similar predictive power to a generalized range-wide species model. Comparisons of model predictions to field growth may have been limited by mortality, phenotypic flexibility, or sample sizes. Our simulation results indicate that muskellunge populations are adapted to specific thermal regimes and further evaluations of population-specific growth patterns in the field are warranted.