The illegal drug’s main byproduct, benzoylecgonine, caused more robust effects than cocaine itself. Wastewater treatment plants often don’t fully process such metabolites, so they are frequently found in bodies of water at higher concentrations than their parent drugs April 23, 2026 10:00 a.m. In experiments, juvenile Atlantic salmon that were exposed to cocaine’s primary metabolite swam more and dispersed farther than their sober peers. Jörgen Wiklund The world’s waterways are becoming increasingly contaminated with pharmaceuticals and illegal drugs—and the pollutants are seeping into marine animals. Cocaine, specifically, has been found in  sharks ,  shrimp ,  mussels  and  eels , but exactly how these human-derived contaminants might be affecting wildlife has remained mysterious. Now, new research offers a first look at how cocaine can alter the behavior of fish in the wild.…