Modelling swimming aquatic animals in hydrodynamic models

Aquatic life exists between very small passive floating objects such as spores, eggs or seeds which are at the mercy of currents through to animals which swim powerfully enough to overcome most natural currents. There is a corresponding scale of cognitive and sensory capability. Coupling hydrodynamic with Lagrangian particle modelling is well established, as is individual based modelling of animal behaviour. These areas have developed rapidly, due to availability of faster computers. These different disciplines have fundamentally different conceptual frameworks, but the combination of techniques offers an unparalleled opportunity to model swimming animals in water more accurately. More accurate models of dispersion, migration and other spatial dynamics would support a better informed ecosystem management and provide methods to define protected areas that are linked in coherent networks. Development plans for tidal power schemes and offshore wind farms mean that predictive models of migrating fish are needed urgently. Statistical models based on correlations become inaccurate as the environments move to previously unobserved states. This is where models based on rules such as individual based models have a unique advantage. I briefly review Eulerian, Lagrangian, coupled Eulerian–Lagrangian water models, water quality models and individual based models of animal movements, navigation and interactive behaviour.