2 weeks Ago By Jonathan Edwards, Dino Grandoni
Young salmon in central Sweden must endure a gauntlet to migrate from their freshwater spawning grounds to the Baltic Sea. Their 28-km route along the Dal River is rife with danger, from northern pike and seabirds to hydropower dams. Four out of five fish don’t make it.
Some Atlantic salmon recently got an unexpected edge, after scientists dosed them with antianxiety drugs meant for humans, not fish. The drug, clobazam, made the fish more independent and faster, research published last week found - but scientists said the seemingly positive effects could belie hidden or long-term consequences for the fish. And the mere existence of the study speaks to a growing problem: We’re turning our rivers, lakes and oceans into soups of pharmaceutical pollution.
“Any sort of deviation from natural behaviours is likely to carry potential consequences,” such as making salmon easier targets for predators, said Jack Brand, researcher at Swedish University of Agricultural Sciences and lead author of the paper published on Thursday in Science . Nearly 1000 pharmaceuticals have been detected in waterways around the world, and scientists say they threaten animals and the people who rely on them. Brand and his colleagues focused on one behaviour of a single species - migration in Atlantic salmon - but he said he can easily imagine exponential consequences when expanding the focus to other drugs, species and waterways across the world.
“Pharmaceutical pollution is this sort of invisible agent of global change,” Brand said..
