ABSTRACT
Simple population models form the foundations of numerous fisheries models, indeed the separation of fisheries modelling from ecological population modelling is only an artificial distinction. This chapter examines the dynamics of some of the fundamental ideas in population biology. All the models exhibit deterministic dynamics; even the chaotic dynamics will follow the same trajectory if the starting conditions are repeated. In nature, of course, such deterministic behaviour would be rare. The models are always an abstraction of what may really be going on. Take care over the concept of “recruitment”, it can mean the post-larval arrival into the stock, however, it can also refer to when individuals become available or vulnerable to a fishery. Usually, in a fully age-structured fisheries model one would implement a selectivity function to describe the different vulnerability of each age-class to a particular fishing gear.
