Meth-addict fish, aggro starlings, caffeinated minnows: animals radically changed by human drugs – study

From brown trout becoming “addicted” to methamphetamine to European perch losing their fear of predators due to depression medication, scientists warn that modern pharmaceutical and illegal drug pollution is becoming a growing threat to wildlife.

Drug exposure is causing significant, unexpected changes to some animals’ behaviour and anatomy. Female starlings dosed with antidepressants such as Prozac at concentrations found in sewage waterways become less attractive to potential mates, with male birds behaving more aggressively and singing less to entice them than undosed counterparts.

The contraceptive pill has caused sex reversal in some fish populations – leading to a collapse in numbers and local extinction events as male fish reverted to female organs. Scientists have said that modern pharmaceutical waste is having significant consequences for wildlife exposed to discharges in their ecosystems, and warned it could have unintended consequences for humans.

Michael Bertram, an assistant professor at the Swedish University of Agricultural Sciences, said: “Active pharmaceutical ingredients are found in waterways all around the globe, including in organisms that we might eat.”

He said evidence of the problem had grown over recent decades, and it was a global issue for biodiversity that deserved more attention.

In a paper published on Wednesday in the journal Nature Sustainability, researchers said the pharmaceutical industry must urgently reform the design of drugs to make them greener.