“Fish that have been exposed to a common anti-anxiety drug are more active and have better chances of survival than unexposed fish,” reports Nature. According to the article, a study published in Environmental Research Letters noted that previous studies had only looked at the harms of pharmaceutical pollutants on fish. So a team led by Jonatan Klaminder from Sweden’s Umeå University exposed Eurasian perch to the benzodiazepine sedative oxazepam and looked for “positive” effects.
“[T]he higher drug concentration improved survival in hatchlings compared with the unexposed and low-concentration groups, and both doses improved survival in the mature fish,” summarizes Nature. “Exposed fish were more active, bolder and less sociable.”
“It’s a new era of contamination research if we want to include pharmaceuticals, because their effects are not as traditional as our thinking,” Klaminder told Nature. Klaminder was similarly quoted in environmentalresearchweb, saying that he hoped the study would “serve as a ‘mind opener’ for the research community.”
In their abstract, the researchers noted that it might not all be good news if there are subsequent cascading effects on other organisms in an ecosystem from these changes in the fish. “This is of concern considering that such effects on exposed organisms still may have substantial ecological consequences,” the researchers wrote. “We conclude that therapeutic effects from pharmaceutical contaminants need to be considered in risk assessment assays to avoid that important ecological effects from aquatic contaminants are systematically missed.”
The effects of the oxazepam on the fish were only studied for thirty days.
Fish flourish on anxiety drug (Nature, August 8, 2014)
Can anti-anxiety drugs boost fish survival? (environmentalresearchweb, August 8, 2014)
The conceptual imperfection of aquatic risk assessment tests: highlighting the need for tests designed to detect therapeutic effects of pharmaceutical contaminants (Klaminder, J et al. August 2014. Environmental Research Letters 9 084003 doi:10.1088/1748-9326/9/8/084003)