The robustness of cyclic dominance under random fluctuations.

We investigate the influence of random perturbations on a recently introduced three-species model that reproduces the empirically observed pattern of cyclic dominance in Fraser River sockeye salmon. Since the sockeye populations are subject to various types of fluctuations affecting their growth and survival, we investigate the robustness of the model under several types of noise. In particular, we evaluate the variation of population sizes around their values in the deterministic model, the frequency of phase shifts in the 4-year oscillation, the extent of synchronization between different sockeye populations, and the response to strong one-time perturbations. Our main conclusion is that cyclic dominance is very stable even under strong noise in this model.