Discrete particle and continous density models of fish migration
We present a discrete stochastic particle model of fish migration that is under development, and contrast it with a continous density model, implemented numerically by a finite element method on a triangular grid. The underlying aim is to aid in the assessment of what type of migration models might be included into a more general prediction model of changes in fish stock size, as well as testing various assumptions on what external factors may influence fish migration. In this respect the finite element model forms a bridge between the particle models on one hand and compartmental models on the other. These are the models presently used to predict changes in stocksize and in these models migration between compartments is simply described in terms of transition matrices. The focus of our presentation is on compuatitonal similarities and differences between the discret and continous models and on what insight we may gain from contrasting one with the other.