A study published in Current Biology found that Atlantic salmon exposed to cocaine and benzoylecgonine (the drug's main metabolite) swam significantly farther and moved more restlessly than unexposed fish in the wild—the first time this effect has been demonstrated outside a lab. The metabolite group swam 1.9 times farther per week than controls, and the benzoylecgonine effect was even stronger than cocaine itself, raising questions about how drug byproducts may affect aquatic wildlife at environmentally realistic exposure levels. The finding is significant because benzoylecgonine often occurs in higher concentrations in natural waters than cocaine itself, yet was previously assumed to be behaviorally inert in wildlife. Researchers emphasize much more work is needed to understand whether these movement changes translate to real ecological consequences—affecting predation, migration, or survival rates.