Rather than blood in the water, sharks are finding drugs in the water. The aquatic predators have tested positive for both legal and illegal drugs in parts of the Bahamas. These substances have the potential to cause behavioral changes in the sharks and indicate that humans have a stronger hand in ecosystem changes than expected, even in isolated places.
This is not the first time cocaine has been found in sharks. A study from 2024 found the drug in Brazilian sharpnose sharks in waters near Rio de Janeiro. But this is the “first report of caffeine and acetaminophen detected in any shark species worldwide and the first report of diclofenac and cocaine in sharks from the Bahamas,” said the study. “We are talking about a very remote island,” said Natascha Wosnick, the 2024 lead study author and a biologist at the Federal University of Paraná, to Science News. The exposure is “mostly because people are going there, peeing in the water and dumping their sewage,” said Wosnick.
The study findings are a “reminder that coastal infrastructure, tourism and marine food webs are tightly connected,” said Tracy Fanara, an oceanographer who helped produce the documentary “Cocaine Sharks,” to Science News. Researchers are still unsure about how detrimental the blood changes could be to the sharks’ health.
“Our primary concern is not an increase in aggression toward humans but rather the potential implications for the health and stability of shark populations," said Wosnick. “Chronic exposure to these anthropogenic compounds, many of which have no natural analogue in marine systems, may lead to negative effects that are still poorly understood.” These effects could be the subject of research in the future. |
