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Sertraline was identified in the brain tissue of hammerhead sharks analyzed by the Eco Shark Project, of UFRJ
Since 2018, researchers from the Eco Shark Project, coordinated by professor Mariana Bata Alonso, from the Federal University of Rio de Janeiro, have been collecting carcasses of sharks accidentally caught in fishing nets in Rio de Janeiro.
Now, a new study has drawn attention due to an unusual finding: the presence of sertraline, an antidepressant used by humans, in the brain of hammerhead sharks.
According to Mariana, the research aims to understand the effects of antidepressants and anxiolytics on these animals. Interest grew after a 25% increase in the consumption of these drugs during the Covid-19 pandemic.
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Sertraline in the brain of hammerhead sharks surprised UFRJ researchers
The team analyzed five parts of the animals: brain, liver, muscle, gills, and ampullae of Lorenzini. The contaminants appeared in all the evaluated organs.
However, the highest concentration of sertraline was found in the brain. The result was noteworthy because, in humans, this medication also acts directly on the nervous system.
The scientific explanation lies in the composition of the medication itself. Sertraline is lipophilic, meaning it has an affinity for fat.
Since the brain is rich in lipids, especially because of the myelin sheath, the substance tends to accumulate more intensely in this region.
Study still investigates if antidepressant alters shark behavior
Despite the discovery, researchers have not yet confirmed whether sertraline causes changes in the behavior of hammerhead sharks.
Mariana Bata Alonso explained that the study is ongoing precisely to understand this possible effect.
This point is considered important because sharks rely on orientation, hunting, and environmental perception to survive.
Any behavioral change, if proven, could indicate a larger problem in the balance of marine ecosystems.
Medication can reach the sea due to sanitation failures
The origin of the sertraline found in the sharks is linked to human consumption. According to the researcher, about 1% of the sertraline ingested by people is eliminated unchanged.
After that, the medication goes through the sewage. The problem is that current treatment plants cannot completely remove this type of drug.
The substance then does not remain only in the water. It can deposit in the marine sediment.
Subsequently, it is ingested by shrimp, passes to larger fish, and finally reaches the sharks’ diet.
Sharks show what might be happening to the health of the oceans
For Mariana, people should not treat sharks as villains. In fact, they function as sentinels of the planet’s health.
The presence of contaminants in these animals indicates that the problem is already circulating through the marine food chain.
Without sharks, the ocean loses part of its balance. These predators control populations of intermediate species and help maintain stable marine environments.
Therefore, a sea without sharks would indicate a deep imbalance.
Researcher warns about consumption of shark and incorrect disposal of medicines
The biologist also made a direct warning to the population: shark is shark.
Species like the hammerhead shark already face a critical threat of extinction in Brazil. Therefore, the consumption of shark meat increases the pressure on vulnerable animals.
Another highlighted point involves the disposal of medications. People should not throw medicines in the toilet, as these substances can go to the sewage and reach the sea.
Eco Shark Project monitors sharks and contaminants since 2018
The Eco Shark Project works on the conservation of marine ecosystems, with a special focus on sharks.
Since 2018, the initiative has been monitoring accidentally captured animals and investigating contaminants present in their organisms.
Previously, monitoring prioritized industrial waste and pesticides. Now, medications such as antidepressants and anxiolytics also concern scientists.
The discovery of sertraline in the brain of hammerhead sharks shows that sea pollution can go beyond visible waste.
It can also involve invisible substances, released in everyday human activities and silently spread through the food chain.
