Study finds cocaine pollution alters salmon movement patterns
An international team of researchers has found that cocaine-related pollution in natural waters can significantly alter the behavior and movement of Atlantic salmon, according to a study published in Current Biology, Qazinform News Agency correspondent reports.
The research was conducted by scientists from Griffith University, Swedish University of Agricultural Sciences, Zoological Society of London and the Max Planck Institute of Animal Behavior. The team examined how exposure to drug residues affects fish behavior in a natural ecosystem, focusing on 105 juvenile Atlantic salmon in Lake Vättern, Sweden.
Scientists assigned the fish to three separate groups: one unexposed control group, one exposed to cocaine, and another exposed to benzoylecgonine, a substance formed as cocaine breaks down and commonly detected in wastewater. Through the use of slow-release implants and acoustic telemetry, researchers tracked their movement patterns over an eight-week period.
The results indicated that salmon exposed to benzoylecgonine showed notably greater mobility, covering longer distances and spreading across larger areas than those in the control group. In some cases, their weekly range nearly doubled, with movements extending up to 12.3 kilometers farther. The impact became more pronounced over time, suggesting cumulative effects on behavior.
“Our findings demonstrate that environmentally relevant concentrations of cocaine and its major metabolite benzoylecgonine can accumulate in the brains of exposed Atlantic salmon - an ecologically and economically important species of high conservation concern - and disrupt the movement and space use of these fish in the wild,” the team wrote.
Researchers also noted that the metabolite had a stronger effect than cocaine itself, highlighting potential gaps in environmental risk assessments, which often focus only on the original substance.
The study emphasizes that changes in fish movement could have broader ecological consequences, as movement patterns influence feeding, predator interactions and population dynamics.
“Given the influence of animal movement on organismal fitness and population dynamics, these findings suggest that cocaine pollution may be added to the growing list of stressors affecting fish in the wild, with yet unknown consequences for long-term population persistence. These results highlight the importance of accounting for illicit drug pollutants when managing and conserving vulnerable aquatic species,” the study concludes.
Earlier, Qazinform News Agency reported that Chinese scientists figured out how tobacco plants produce nicotine.
