A Sign Your Fish Might Be on Drugs: Risky Behavior

Media article: https://www.nytimes.com/2025/04/10/climate/salmon-anti-anxiety-drugs.html

Scientific article: https://www.science.org/doi/10.1126/science.adp7174

Pharmaceuticals are underestimated as a source of pollution throughout the aquatic environment. The relatively lower concentration in raw water (ng/L to μg/L) and less perceivable sources of waste (pharmaceutical manufacturing facilities and human/animal excretion) concealed their threats to the ecosystem. Nearly 1000 different active pharmaceutical ingredients (APIs) have been detected in water bodies across the world, and removing those chemicals, especially those designed to be resistant to biological breakdown, is difficult for either traditional wastewater treatment facilities or microbes. A study done by EPA in 2014 confirmed that effluent samples from 50 large publicly owned treatment works contain at least one of 56 measured APIs.

Reports show extensive misuse or even abuse of psychoactive medication in US. 25% among the US youth aged 12-17 have been reported using psychoactive prescription medications. Opioids, stimulants, depressants and cannabis are most abused among the lists. Abuse of these is more than jeopardizing the health of users. The non-metabolized parts to be excreted by drug users, and incorrect disposal of drug leftovers by flushing or landfilling finally result in the flowing of these pharmaceutical pollutants into water circle. 

The Flow of Pharmaceuticals: Many of the more than 4,000 prescription medications used for human and animal health ultimately find their way into the environment. They can pollute directly from pharmaceutical manufacturing plants or from humans and animals. As these chemicals make their way into terrestrial and aquatic environments, they can affect the health and behavior of wildlife, including insects, fish, birds, and more. (Source: https://www.usgs.gov/media/images/pharmaceuticals-move-throughout-aquatic-environment)

In 2017, research reported that water samples from 30 rivers covering 7 larger European catchments contain over-limit benzodiazepines. Clobazam, among the most frequently detected, has a maximum concentration of 11 ng L^-1. Although many drugs function only at high doses, psychoactive drugs designed to be effective at low concentration, and hence the ng L^-1 level is enough to change the behaviors of living creatures. The media article “A Sign Your Fish Might Be on Drugs: Risky Behavior” on The New York Times cited a recent peer-reviewed work on such influence. Researchers from Sweden studied the river-to-sea migration of salmon smolts, with or without treatment of anxiolytic pharmaceutical pollutant, clobazam, at environmentally relevant level. Clobazam-exposed juvenile salmons altered their shoaling behavior to a less-cohesive group when facing higher chances of predation, which leads to heightened vulnerabilities to predators. On the other hand, their risk-taking behavior facilitates the salmons to pass faster through hydropower dam passages – a major threat on their way of migration where five-fold predation happens – therefore a higher success rate of final arrival to sea. Although the behavior change is visible and the long-term effect is potential, the authors of the scientific article didn’t conclude with any predictable consequence of such an influence. The media article supplemented with a possible outcome that wrong timing and wrong volume of successful migration can break the balance of ecosystems.

I would rate 7/10 for this The New York Times article. The author extracted the key information from the scientific paper, arouse the awareness of a type of overlooked pollutant, and provided possible outcomes of such behavior change that were not included in scientific paper. However, the article is simply a summary of the experiments from the other paper, not showing too much positive or negative attitude towards the phenomenon. The inset video fails to demonstrate any behavior change and took me a few minutes to realize it doesn’t contain any experimental detail. Extra 0.5 point is credited for not forcing me to subscribe.