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====== UTLH ======
Salmon migration affected by drug pollution in water from antianxiety medication
[[https://uniteto.live/fr/|UTLH]]
Hatched in quiet streams and rivers, salmon undertake a perilous journey to reach the open ocean where they become mature adults. Over millions of years, generations of young salmon have migrated great distances, in some cases traveling hundreds of miles from freshwater systems to the sea. However, modern salmon face a hurdle that was unknown to their ancient ancestors: pharmaceutical pollution that changes their migration behavior.

Recently, researchers discovered that when a drug called clobazam accumulates in salmon’s brains, migrating fish reach the ocean sooner and navigate dam obstacles faster. On the surface, this change might seem helpful to salmon. However, any deviation from normal animal behavior through human activity — particularly when psychoactive substances are involved — is a red flag, and the full extent of how drug pollution may alter salmon health, behavior and reproduction is still unknown, scientists reported April 10 in the journal Science.
Clobazam, which is commonly found in wastewater, belongs to a group of medicines called benzodiazepines, which depress the central nervous system. The drug is used to prevent epileptic seizures, for short-term treatment of anxiety and to treat anxiety-related sleep disorders. But because neural wiring in fish resembles that of mammals, fish are highly susceptible to the effects of drugs that tweak human neurochemistry, said Dr. Christopher C. Caudill, a professor in the department of fish and wildlife sciences at the University of Idaho.

“Humans share a large amount of biological architecture with fishes — our physiology and anatomy are remarkably similar. Thus, it is intuitive that psychoactive drugs alter the behavior of both fishes and humans,” Caudill, who was not involved in the research, told CNN in an email.

Prior research showed that benzodiazepines could alter behavior in Atlantic salmon (Salmo salar), but they did so under conditions unlike those experienced by wild salmon, said study coauthor Dr. Marcus Michelangeli, a lecturer in the School of Environment and Science at Griffith University in Queensland, Australia.

“Those studies were largely conducted in laboratory settings, only tracked movement over short distances — less than 100 metres (328 feet) — or used drug concentrations much higher than what salmon would typically encounter in the wild,” Michelangeli said via email.

“Our study took a different approach. We followed the entire river-to-sea migration of juvenile salmon in a natural river system, using drug concentrations that match what fish are actually exposed to in the environment.”

The field investigation’s findings highlight the growing risks pharmaceutical pollutants pose to wildlife populations across the globe, according to Michelangeli.

Resumé af ændrigner