Our antidepressants impact the behavior of marine fauna

Do you know what fluoxetine is? This is a very famous psychoactive agent found in the drug Prozac. Those who have flirted with depression know that it is a drug designed to fight this illness.

Prozac was launched in the United States in 1988 and became a generic drug in 2001. Currently, Prozac is among the best-selling prescription drugs in the world, with 25 million prescriptions in the United States, in 2018 alone.

We dump some of our medicine into the world’s oceans

Other important information, did you know that most drugs are only partially absorbed by our body? Antidepressants like Prozac, which contains fluoxetine, are one of them. What the body does not absorb ends up being flushed down the toilet, which then goes down the sewers.

Eventually, anything that wastewater treatment and treatment plants can’t deal with ends up being released into the ocean and, as Science Alert puts it, “is unknowingly prescribed to the marine life that lives there.” But how serious is this exposure of marine species to our drugs? A team of scientists led by evolutionary ecologist Giovanni Polverino from the University of Western Australia wanted to respond.

Fish under psychoactive substances lose their individuality.

In their study, published in the Proceedings of The Royal Society B, the scientists say they observed the behavior of several generations of guppies, a species of freshwater fish, that were subjected to low-level concentrations of fluoxetine. And at a high level in the laboratory to obtain information on the behavior of fish living in similar conditions in the oceans.

The Guppy (Poecilia reticulata). Photo credit: Shutterstock / Pavaphon Supanantananont

The result of their study was unequivocal: the fish gradually lost their individuality depending on the level of exposure to the psychoactive. Furthermore, these fish would have also started to act in the same way. If this finding worries scientists, it is because, in the long term, it could endanger the population of marine species by losing their survival instinct and jeopardizing their reproductive capacity and genetic diversity.

Ultimately, antidepressants could harm the reproduction and survival of marine species

Poliverino effectively states that “for fish populations to thrive in the face of environmental change, group members must behave differently from each other.” However, he notes, the study showed that exposure to fluoxetine erodes this behavioral diversity.

The scientists conclude by stating that “the side effects of psychoactive pollutants in wildlife are a growing concern”, but more studies will likely be needed, increasingly extended periods to determine how serious the situation is. In any case, we now know that our medicines represent another great threat to marine species, in addition to other causes of ocean pollution.