Eyes as a Novel Target of Psychoactive Contaminants in Fish

Psychoactive drugs are prevalent
aquatic contaminants that target
neurotransmitter systems conserved across vertebrates. While their
effects on fish brain chemistry and behavior are increasingly recognized,
impacts on sensory systems such as vision remain largely unexamined.
Here, we demonstrate that environmentally relevant mixtures of psychoactive
drugs accumulate in the eyes of European perch (Perca fluviatilis) under both laboratory and field conditions, often at higher concentrations
than in the brain. This ocular accumulation significantly alters neurotransmitter
levels critical to visual processing. Our findings reveal a previously
overlooked mechanism of sensory disruption with potential consequences
for fish behavior, ecological interactions, and population fitness.
Current environmental risk assessments, which rarely consider the
visual system, may therefore underestimate the ecological impact of
pharmaceutical pollution. These results underscore the need to expand
ecotoxicological frameworks to include sensory endpoints and visual
function as sensitive indicators of contaminant exposure in aquatic
organisms.