Cocaine in waterways alters fish dispersal

A telemetry experiment in Sweden implanted juvenile Atlantic salmon with slow‑release patches containing cocaine or its human metabolite benzoylecgonine and tracked their movements for eight weeks. Fish exposed to the drugs swam farther and dispersed across the lake more than controls, with benzoylecgonine producing the largest effect. — If human recreational drugs change where and how wildlife move, that raises policy questions for wastewater treatment, fisheries management, and ecological risk assessments.