Abstract: In this paper, we study the population dynamics of the Mediterranean monk seal in the National Marine Park of Alonissos, Greece. As a first general approach, the well-known logistic model and a modified version are used. As a second approach, a -logistic type model with delay is adopted. Finally, a modified version of this delay model is proposed and compared with the others. The results are illustrated using computer simulations. [Copyright &y& Elsevier]