Social and individual behavioral responses to impaired and changing visibility  
Hannah M Anderson, Emily Elsasser, Sigal Balshine. McMaster University, Hamilton, Ontario, Canada

Exposure studies are typically conducted under stable conditions. Unfortunately, natural environments experience frequent changes in environmental conditions, and we are only now beginning to understand how animals react to this variation. In aquatic habitats, visibility often shifts rapidly with daily changes such as daylight, periodic algal blooms and rain-agitated suspended sediments. We tested how visually challenging environments affected the social and individual behavior of zebrafish, Danio rerio, a shoaling, visually-oriented species. Specifically, we tested how social cohesion and space use of zebrafish shoals change under clear water, stable but visually impaired environments, and fluctuating visual conditions using both suspended sediment and low light as mediums. Preliminary results indicate consistently poor visibility decreases boldness and aggression compared to both clear and fluctuating conditions while increasing shoaling compared to clear water. Further, boldness was only affected by suspended sediment and shoaling only affected by low light. These results emphasize the importance of considering both the ecological context and the form of stimuli in research.