Mode change in the dynamics of exploited limited population with age structure

This study focuses on the dynamics of exploited limited population with age structure and compares dynamic modes of population models with and without exploitation while considering age-specific harvesting. Transcritical, period-doubling, and Neimark-Sacker bifurcations occur in the population models. In the case of juvenile harvest, the way of stability loss does not depend on the harvest rate. However, in the case of adult harvest, the hydra effect occurs, which is an increase in harvest rate that subsequently increases the stationary size of the young group. As a rule, harvesting leads to dynamics stabilization. However, the models reveal multistability. Hence, in the case of exploitation, different dynamic modes can occur with their attraction basins at the same population parameter values. Irregular harvesting or a changing harvest rate may also result in fluctuations in exploited population size because the current population size can shift from one attraction basin to another. Controlling exploited population dynamics is sufficient to shift and retain the population number to within the attraction basin of the dynamic mode selected.