Fish on the pill: Impacts of the oestrogenic pollutant 17α-ethinylestradiol on fish behaviour

Pharmaceutical pollution is an emerging global concern, yet its behavioural effects on wildlife remain poorly understood compared to traditional endpoints such as morphology or physiology. This thesis examines how exposure to the common pollutant 17α-ethinylestradiol (EE2), a synthetic oestrogen used in the human contraceptive pill, influences fish behaviour. Using three species with contrasting ecologies and reproductive strategies, I tested whether behavioural responses to environmentally relevant EE2 exposure were consistent across systems. Responses varied markedly among species. These findings demonstrate that sensitivity to hormone pollution is not universal but depends on species biology and environmental context.