Fish are ‘getting addicted to meth’ flushed into rivers, study warns

This could be ‘another example of unexpected pressure on species living in urban environments’, researcher says

Scientists put brown trout in meth-contaminated water for eight weeks (Getty Images/iStockphoto)

Fish in waters contaminated with methamphetamine develop an addiction to the drug, according to new research.

Scientists said this caused changes which had “unexpected adverse consequences” to individual fish and population levels.

Czech researchers isolated brown trout in a tank of water laced with a level of mathamphetamine that has been found in freshwater rivers to see whether they were at risk of developing an addiction.

After eight weeks, they were moved into a freshwater tank.

When offered the choice between the two tanks, the trout chose the meth-contaminated water in the first four days afterwards as they suffered withdrawal, according to the research published in the Journal of Experimental Biology.

The fish that had spent time in the water with methamphetamine were also less active than those that had not, the findings showed.

“Altered movement behavior and preference for methamphetamine during withdrawal were linked to drug residues in fish brain tissues and accompanied by brain metabolome changes,” the researchers, from the Czech University of Life Sciences Prague and the University of Southern Bohemia said.

“Our results suggest that emission of illicit drugs into freshwater ecosystems causes addiction in fish and modifies habitat preferences with unexpected adverse consequences of relevance at the individual and population levels.”

The research continued: “As such, our study identifies transmission of human societal problems to aquatic ecosystems.”

“The elicitation of drug addiction in wild fish could represent another example of unexpected pressure on species living in urban environments”, Pavel Horký from the Czech University of Life Sciences Prague said.

Other research has previously looked into the impact of drugs polluting waters.

In 2018, a study suggested cocaine flushed into rivers was making eels “hyperactive” and threatening their survival.

And prescription drugs can also harm wildlife, according to a study published a year later, which found medication such as antibiotics and epilepsy drugs were increasingly being found in rivers at levels which could damage ecosystems.