Cyclical fluctuations and step-wise changes in new models of population dynamic

Author analyzed new nonlinear mathematical model of population reproductive performance based on differential equation with discontinuous right-hand member. Model is implemented in form of hybrid automaton. Also the mathematical interpretation of deformation recruitment curves for sturgeon population \it{Acipenser guldenstaedtii} was developed. Research of the model predicts existence of cyclical fluctuations of a population in conditions of not a fishing main role.