A model for Arctic Charr populations in Cambridge Bay considering fluctuating environment
Pasban Roozbahani, Negin
The research focus in this thesis is twofold. First, we formulate an age- and stage-structured discrete-time matrix population model to describe the behaviour of an Arctic Charr population. Given the properties of the model, a weak ergodic behaviour is expected in the long run. Then, utilizing data collected in Cambridge Bay and using a generalized weighted least squares method, model parameters are estimated. The results of estimated parameters and a sensitivity analysis reveal the importance of early-ages individuals in the limiting behaviour of the population. Second, we investigate how the fitness of such a population might change in a fluctuating environment. We assume three types of yearly environments; good, intermediate and bad. A discrete time Markov chain governs the transitions between environmental states. The results in this step also suggest a weak ergodic behaviour for the population; a stochastic growth rate is provided for the population in this fluctuating environment.
Arctic Charr, Multi structural population model, Fluctuating environment, Markov chain, Ergodicity