Overview
- Researchers writing in Current Biology on Monday reported that juvenile Atlantic salmon exposed to benzoylecgonine swam up to 1.9 times farther per week and ranged as much as 12.3 kilometers beyond controls.
- The team tracked 105 fish in Sweden’s Lake Vättern using acoustic tags and slow-release implants that delivered cocaine, its metabolite, or a neutral control.
- Benzoylecgonine changed movement more than cocaine, which challenges risk checks that focus on the parent drug even though the metabolite is often more common in waterways.
- Scientists noted the implants do not match how fish meet dilute pollution in flowing water, and warned that extra swimming could drain energy and push fish into poor habitat or new predators.
- The authors said the findings do not signal a food-safety risk for people and outlined plans to test other species and link movement changes to survival and reproduction.