A new Eulerian–Lagrangian agent method to model fish paths in a vertical slot fishway

Abstract

An individual-based model (IBM) to simulate the movement of a single fish through a vertical slot fishway has been developed. The turbulent water flow in the fishway was first obtained using CFD-software. Trajectories of live fish measured by Rodriguez et al. (2011) were superimposed on several different parameters characterizing the flow, such as the turbulent kinetic energy (TKE). The correlations between these hydrodynamic parameters and the measured trajectories were examined and TKE was identified as the single most important stimulus. To mimic positive rheotaxis, the mean velocity was adopted as a secondary agent. The new Lagrangian IBM-model was combined with the Eulerian CFD-model to an Eulerian–Lagrangian agent method. This ELAM approach was used to compute the trajectory of a virtual fish. The simulated trajectories were in good agreement with their measured counterparts in the same fishway. Both the preferred direct route and the alternative longer route through an active pool were faithfully reproduced.