Study Detects Cocaine, Caffeine and Other Substances in Sharks off The Bahamas

A study published on ScienceDirect has identified contaminants of emerging concern in sharks from The Bahamas. Researchers tested 82 sharks across five species: lemon, Atlantic nurse, blacktip, Caribbean reef and tiger sharks. Of these, 23 sharks tested positive for four substances: acetaminophen, diclofenac, cocaine and caffeine.

The contaminants are recognized in marine environments, particularly in areas with high tourism activity. The study notes that while cocaine has been detected in sharks previously, this research provides new findings on other substances. In 2024, more than 10 sharks off the coast of Brazil tested positive for cocaine.

“This was 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, an environment commonly described as pristine.”

The analysis revealed physiological differences in affected sharks. Those with the contaminants showed altered levels of triglycerides, urea and lactate compared to sharks without them. These changes suggest potential impacts on shark health, though further research is needed to determine long-term effects.

Contaminants of emerging concern, such as pharmaceuticals and illicit drugs, enter oceans through wastewater discharge, runoff and tourism-related activities. The Bahamas, a major tourism destination, relies on its marine ecosystems for economic and ecological value. Sharks play a key role in these ecosystems as apex predators, helping maintain balance in coral reefs and fisheries.

This study highlights growing concerns about pollution in coastal waters. Affected populations include local marine species, tourism operators and communities dependent on healthy oceans. International monitoring efforts, such as those by environmental agencies, may increase in response to such findings.