Modelling of the nonlinear dynamics of pacific sockeye salmon

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The project shall use computational and analytical methods to investigate the nonlinear dynamics of sockeye salmon, including the interaction with their predators, their food source and their competitors. The periodic four-year oscillation of these fish has been found to be due to a “strong resonance”, and it is thus a generic phenomenon that may occur in populations with seasonal dynamics and a generation time between 4 and 5 years. In particular, the conditions shall be established under which the strong resonance, found in a three-species version of the model, occurs in even further simplified as well as in more comprehensive models. We will also investigate the influence of noise and the conditions for the occurrence of other attractors (fixed point, oscillation with period 2, quasiperiodic behavior). The influence of the fishing industry, of lake fertilization and of spawning channels on the dynamics of the salmon shall be studied. The results shall be compared with known field data.