Anxiety drugs found in rivers make salmon take more risks : NPR

In many streams and rivers, fish swim in the true soup of medicine. New research shows that the soup’s components can be confusing behaviour.

Atlantic salmon exposed to anti-anxiety medications while traveling It was more successful Researchers reported Thursday when reaching destinations than drug-free fish Science. Their success could be attributed to increased boldness, researchers found that it was a trait that could ultimately harm fish in the long term.

“In the face of that, giving a drug to a fish sounds beneficial,” said Jack Brando, a biologist at the Swedish University of Agricultural Sciences. “However, deviations from natural behavior can have a wide range of potential negative consequences for the population.”

Scientists have detected over 900 drug components in natural waterways around the world, from antibiotics to antidepressants. Many of these drugs, especially those that act on the mind, target parts of the brain that are shared by many different species.

Over the past decade or so, lab experiments have shown that naturally occurring concentrations of such drugs can alter fish behavior. In the lab, drug fish are often antisocial, less fearful, and more likely to take risks and fall into risky situations.

But it has been much more difficult to study what these drugs do to fish in the wild, Brand said. “Obviously, we can’t throw a lot of medicine into the river.”

Instead, he and his colleagues basically dumped the medicine into fish just before they moved from the Dal River in Sweden to the Baltic Sea. The team transplanted a delayed release drug into a young Atlantic salmon raised at 279 hatch sites. Implants released controlled doses of two drugs in various combinations: clobazam, a benzodiazepine often used to treat anxiety, and tramadol, an analgesic.

“In human patients, tramadol and clobazam are expected to have negative interactions, often not prescribed together,” Brand said. Researchers suspected that combos could also be harmful to fish. And, both drugs are commonly found in natural ecosystems, but are not detectable in this river belt.

They also embedded tracking tags that allowed researchers to track fish as they moved from the Swedish release site across multiple hydroelectric dams into the Baltic Sea.

Bold salmon?

The crobazam seemed to support the success of young salmon migratory birds. Researchers found that more fish exposed to crobazam reached the Baltic Sea than unexposed fish. It seemed to have no effect on tramadol.

These results surprised the brand considering that they are known about how these drugs affect lab fish. “We expect a reduction in survival rates in the wild,” he said. It seemed rewarding in the transition context. It could have something to do with the dam. The dam has a large, spinning turbine to produce hydroelectric power generation.

“If they’re hit by the blade, they could die, so that’s not good,” said Olivia Simmons, a salmon biologist at the Norwegian Institute of Natural Sciences, who is not involved in the research. Typically these turbines slow the salmon, she said, and the fish understand how to pass an intact turbine.

However, the researchers found that fish exposed to crobazam cross the dam 2-3 times faster than non-exposed fish, saving an average of about five hours. “Maybe the bolder fish are spending less time deciding whether to pass through the scary turbines,” Simmons said.

Brands share their interpretations. “I suspect that these fish exposed to clobazams are more risky and more lonely, and therefore they are sort of lined up it through it through the dam, rather than waiting for a friend of salmon,” he said.

Wideer results

Its boldness appears to have been rewarded with more fish than it reaches the ocean, but it can be expensive in other contexts.

“After they arrived in the Baltic Sea, the salmon don’t know what happened. Did they have better or worse survival?” said Karen Kidd, an ectotoxicologist at McMaster University. Subsequent lab experiments suggest possible answers.

Brand and his colleagues have discovered that salmon exposed to crobazam are unlikely to form a school with other fish, making it easier for predators to pick them up.

Whatever the ultimate outcome of exposure, the study confirms that the types of behavioral changes seen in the lab can be converted into the wild, Kidd said. “This is truly a place where the novelty of this experiment shines through.

Still, there are many unknowns.

“We don’t know what these anti-anxiety and painkillers, as well as antibiotics, anti-epileptics, chemotherapy, etc. “That’s a global concern.”

There are potential solutions to the problem. Building a better wastewater treatment plant will help you catch these chemicals before polluting the environment. Drugs can also be designed to break down more easily in the environment, Kidd said.

“This is an important step forward to ensure that anything in the environment does not cause any adverse harm.”