It might not seem like much but fish overall are individuals even if they don’t look like it. They are not all the same, but some fish seem to be losing what makes them unique because of a very unexpected reason.
According to more recent research, ‘psychoactive pollution’ has been suppressing ‘individual differences’ in fish behavior. This was gone over in the study titled ‘Psychoactive pollution suppresses individual differences in fish behavior’ that was published in The Royal Society Publishings on the 10th of February this year (2021). While most people don’t think about this the drugs that we take prescribed or not come out in our urine which ultimately enters the sewage system and thus finds its way to where fish live. Sure, some get caught in wastewater treatment plants but not all of it does and when this happens the ocean life present suffers in ways we might not realize at first.
The abstract of this study goes as follows:
Environmental contamination by pharmaceuticals is global, substantially altering crucial behaviours in animals and impacting on their reproduction and survival. A key question is whether the consequences of these pollutants extend beyond mean behavioural changes, restraining differences in behaviour between individuals. In a controlled, two-year, multigenerational experiment with independent mesocosm populations, we exposed guppies (Poecilia reticulata) to environmentally realistic levels of the ubiquitous pollutant fluoxetine (Prozac). Fish (unexposed: n = 59, low fluoxetine: n = 57, high fluoxetine: n = 58) were repeatedly assayed on four separate occasions for activity and risk-taking behaviour. Fluoxetine homogenized individuals’ activity, with individual variation in populations exposed to even low concentrations falling to less than half that in unexposed populations. To understand the proximate mechanism underlying these changes, we tested the relative contribution of variation within and between individuals to the overall decline in individual variation. We found strong evidence that fluoxetine erodes variation in activity between but not within individuals, revealing the hidden consequences of a ubiquitous contaminant on phenotypic variation in fish—likely to impair adaptive potential to environmental change.
It’s quite concerning that this is happening actually, while psychoactive drugs target receptors in our brains, the fact that they are in some ways affecting non-target species is quite alarming when you really think about it. Sure, they might just be fish but who knows what else may be affected in this manner or to the extent this is happening. What do you think about all of this?