An international study by biologists from Monash University and the University of Tuscia uncovered significant impacts of pharmaceutical pollutants on fish. Over a five-year investigation, researchers focused on how the antidepressant fluoxetine, commonly known as Prozac, affects wild-caught guppies. This study, published in the Journal of Animal Ecology, highlights how exposure to this pollutant changes fish behavior, life history, and reproductive traits.

Pharmaceutical pollutants like fluoxetine often enter water bodies through wastewater discharge. Though found in low concentrations of rivers, lakes, and oceans, their effects on aquatic life still need to be fully understood. In this study, researchers exposed guppies to three different concentrations of fluoxetine over multiple generations to observe changes in their behavior and physical traits. They discovered that even low levels of fluoxetine led to alterations in the guppies’ body condition, reproductive organs, and sperm quality.

The study found that fluoxetine increased the size of the gonopodium, a reproductive organ in male guppies, but reduced sperm velocity, which is crucial for successful reproduction. Additionally, the guppies showed reduced behavioral plasticity, meaning they could not adapt their activity and risk-taking behaviors to different situations. These changes disrupt the natural balance of traits that guppies rely on for survival and reproduction.

The researchers noted that chronic exposure to fluoxetine also affected the relationships between various traits. For example, the usual connection between activity levels and body condition was altered. The study’s findings underscore the need for stricter regulations on pharmaceutical pollutants and highlight the broader ecological impact of these chemicals on aquatic ecosystems. Understanding these effects is crucial for protecting wildlife and maintaining healthy environments.

References

• Aich, U., Polverino, G., Yazdan Parast, F., Melo, G. C., Tan, H., Howells, J., Nosrati, R., & Wong, B. B. M. (2024). Long-term effects of widespread pharmaceutical pollution on trade-offs between behavioural, life-history and reproductive traits in fish. Journal of Animal Ecology, 1365-2656.14152. https://doi.org/10.1111/1365-2656.14152
• Monash University. (2024, August 27). Antidepressant pollution is rewiring fish behavior and reproduction, biologists reveal. Phys.Org; Monash University. https://phys.org/news/2024-08-antidepressant-pollution-rewiring-fish-behavior.html