AN AUGMENTED CLARK MODEL FOR STABILITY OF POPULATIONS

A simple modification of a frequently employed age-structured model fo r population dynamics is presented. This augmented formulation allows the assessment of the impact of age-dependent harvest mortality on pop ulation stability. The characteristic frequencies of the predicted osc illations are discussed. The period of oscillation is almost independe nt of survival and the exact functional form of the recruitment functi on, and it is not equal to twice the mean age of mature animals, as su ggested earlier. It is shown that increased survival before reproducti on has a destabilizing influence for populations exhibiting an overcom pensatory recruitment function.