Improving Downstream Passage for Multiple Species - the Importance of Understanding Fish Behaviour

There is a now an urgent need to return to fundamental first principles and quantify fish behaviour in response to behavioural stimuli (e.g. hydrodynamics, acoustics or lights). This information is required to develop more robust screening and guidance systems and improve downstream fish passage for multiple species. This presentation will outline studies from the International Centre for Ecohydraulics Research which aim to better understand and quantify fish response to environmental stimuli, including velocity gradients and light. The general behavioural trends observed on encountering velocity gradients will be contrasted between species, including salmonids and the critically endangered European eel (Anguilla anguilla), which are often considered more “structure oriented” and particularly susceptible to injury / mortality during passage through hydropower turbines. We will conclude with how this fine scale behavioural information may be applied to the development of more efficient behaviour guidance devices and suggest directions for future research.