Experts suggest that the cocaine may be entering the waters through illegal drug labs or the excrement of drug users. Although it is also possible that packs of cocaine lost or dumped by traffickers at sea could contribute, researchers consider this to be less likely.

Sara Novais, a marine eco-toxicologist at the Marine and Environmental Sciences Centre of the Polytechnic University of Leiria, emphasized the significance of the findings, calling them “very important and potentially worrying." All the female sharks in the study were pregnant, but the effects of cocaine exposure on the foetuses remain unknown.

Further research is needed to determine if cocaine is altering the behavior of these sharks. Previous studies have indicated that drugs can have similar effects on animals as they do on humans, raising concerns about the impact of cocaine on marine life.

Last year, chemical compounds such as benzoylecgonine, a byproduct of cocaine metabolism, were found in seawater samples off the south coast of England.