INDIVIDUAL VARIABILITY AND SPATIAL HETEROGENEITY IN FISH POPULATION-MODELS

Fish populations consist of non-identical individuals inhabiting heterogeneous environments and moving about the environment in a manner that maximizes their individual fitness. No study has fully integrated these characteristics of fish populations into a single model. In this paper we propose a new class of model that includes each characteristic in a unified description of populations. To lay the foundation for these models we review models concerning (1) population dynamics in heterogeneous environments, (2) the effects of individual variability on population dynamics, and (3) individual movement and habitat selection rules. The models that we propose allow investigators to explore the population-level consequences of novel changes in the environment, and of different individual fitness maximization strategies. The strengths of our proposed class of model lie in their mechanistic, individual-level description of fish growth, movement and survival. Correctly depicting these mechanisms presents important challenges in developing such models. Despite these challenges, mechanistic models like those we propose should greatly increase our understanding of the interaction between environmental heterogeneity and fish population dynamics and distributions. © 1994 Chapman & Hall.