Consider the Bigger Picture: The Effect of Multimodal Sensory Integration on Fish Passage Behaviour

Fish passes are an important tool for minimizing the negative impacts of instream infrastructure on ecologically and economically important fish species. However, their efficacy is not perfect, and fish do not always respond to these structures as expected. One reason for this is that we do not have a complete understanding of what sensory stimuli influence fish passage behaviour. While considerable work has gone into quantifying the effect of the hydrodynamic environment on these behaviours, much less is known about how other sensory channels affect them, despite evidence that visual, auditory, and even olfactory stimuli play a role in governing these behaviours. Thus, we call for an increased consideration of how fish passage behaviours are impacted by information detected across multiple sensory channels. Developing this knowledge will aid the retrofit and improvement of exisiting fish pass structures, along with the design of new fish pass structures in the future, and the development of new predictive models designed to explain the behaviour of fish in the proximity of instream barriers.