Effects of short-term turbidity on sensory preference and behaviour of adult fish

When changing environments make the primary sensory modality less useful or reliable, animals may shift their reliance to a different sensory modality. However, such plasticity in sensory modalities may be unlikely outside of critical developmental periods or may depend on the type of behaviour associated with the sensory response. Animals’ previous experience with a particular environment and its influence on the reliability of cues may also constrain the occurrence of sensory shifts. Here, we ask about the impacts of changing environments that occur during adulthood on sensory behaviour. Specifically, we housed adult zebrafish, Danio rerio, for 6 weeks either in constantly clear water, or in water that was periodically turbid. We then compared the two groups in terms of their (1) response to a reflexive optomotor stimulus, (2) choice for visual versus olfactory cues in a foraging context and (3) social behaviour. We found that fish with experiences in the turbid context responded less robustly to a reflexive visual stimulus and responded to olfactory as opposed to visual cues as the first choice, suggesting a shift in their primary sensory modality. However, other behavioural measures (e.g. shoal cohesion, charge rate, activity level) depended more on the context in which they were measured than on recent experience. Taken together, these results suggest that recent experiences in particular physical contexts may impact the use of different sensory modalities and visual physiology, but that these effects depend on the type of behaviour being considered. These compensatory shifts between sensory modalities may help animals to buffer other forms of behaviour from major changes in the environment.