Researchers in Sweden have found that when wild perch are exposed to Oxazepam, a common anti-anxiety medication, they undergo surprising changes in their behavior and feeding rate.
“Normally, perch are shy and hunt in schools. This is a known strategy for survival and growth. But those who swim in Oxazepam became considerably bolder,” explains ecologist Tomas Brodin, lead author of the article. Braver and less social, the drug-exposed fish also ate much faster.
Low concentrations of biologically active drugs are commonly found downstream from sewage treatment plants. The new study, published in the journal Science, is the most recent paper to highlight the toll that pharmaceutical pollution is having on aquatic ecosystems. Effects were seen at levels commonly found in surface waters.
Brodin and his research group are now investigating the food web consequences of a change in perch feeding behavior. If perch become more efficient feeders, it could lead to shifts in species composition in polluted streams as well as unexpected impacts, such a rise in algal blooms.
Globally, pharmaceutical use is on the rise. And wild fish populations are being exposed to a cocktail of pharmaceutical drugs, from psychiatric drugs and birth control pills to antihistamines.
More work is needed to understand the long-term ecosystem effects. In the mean time, to ensure the health of our freshwaters we need to develop sewage treatment plants that can effectively capture environmentally hazardous drugs.
Web Links
Scientific American
Science
http://www.sciencemag.org/content/339/6121/814.abstract
Umea University
http://www.eurekalert.org/pub_releases/2013-02/uu-fbb020813.php
AAAS
http://www.eurekalert.org/pub_releases/2013-02/aaft-mdf020813.php
Photo, taken on June 27, 2010, courtesy of e-Magine Art via Flickr.
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