The Tribune

By EARYEL BOWLEG

Tribune Staff Reporter

ebowleg@tribunemedia.net

A STUDY detecting traces of cocaine, caffeine and common painkillers in sharks off Eleuthera is being criticised by a local shark tourism operator, who warns the findings risk overstating the condition of Bahamian waters.

The peer-reviewed research, published in Environmental Pollution, analysed blood samples from 85 sharks across five species and found four contaminants — caffeine, cocaine, acetaminophen and diclofenac — in 28 sharks from three species.

Travis Cove, an operations manager for Stuart Cove, said the conclusions could unfairly damage the reputation of waters widely regarded as pristine.

“From my perspective as a shark tourism operator, this study feels overstated in a way that could unfairly damage the perception of otherwise pristine waters. While the researchers used credible analytical methods, the actual findings are extremely limited—only a small fraction of the 85 sharks sampled showed detectable compounds, and cocaine in particular was found in just two individuals,” Mr Cove said.

“That’s not evidence of widespread contamination; it’s evidence of trace, isolated detections. The study also relied on blood serum, which only reflects very recent exposure, not long-term environmental conditions. In an area with any level of human activity, especially tourism and boating, detecting minute traces of common substances like caffeine isn’t surprising and doesn’t indicate a polluted ecosystem.”

He also raised concerns about the study’s methodology, noting the absence of standard laboratory blank controls, which he said could allow for minor contamination during analysis, particularly for substances like caffeine.

“Even the authors acknowledge that they cannot establish causation between these detections and any biological effects in the sharks,” he said. “From an industry standpoint, presenting these findings without proper context risks misleading the public into thinking the marine environment is broadly contaminated, when in reality the data only suggest limited, low-level exposure that is neither widespread nor proven to be harmful.”

The researchers linked the presence of contaminants to human activity, including tourism-related development, vacation homes and wastewater discharge, and identified caffeine as a key indicator of such impacts.

Bahamian environmental scientist Dr Ancilleno Davis said the study follows international standards and described it as “well implemented,” but noted limits in how broadly the findings can be applied.

“My key thoughts are this is a very interesting and well implemented study,” he said. “The Cape Eleuthera Institute has led The Bahamas on the shark biology and ecology work in The Bahamas for years.”

Dr Davis said the sample size and location limit the conclusions that can be drawn.

“A map of the area surveyed would be useful to allow future comparisons if the research is replicated in other areas of The Bahamas,” he said. “Eigthy-five sharks in my opinion does not represent The Bahamas. Eleuthera does not represent The Bahamas. The coastal areas of Eleuthera on the inside of The Bahamas may also differ from the Atlantic Coast.”

He added that testing blood serum captures only certain contaminants and may not reflect the full scope of environmental exposure.

“That's why they're using those tests for those types of drugs and caffeine and stuff that if a shark ingest them from the environment or if it's in the water and a high enough concentration, it will go through their gills, their stomachs, or maybe through the fish that they eat,” he said.

“Some fish might be eating the trash or waste from the boats or vessels, and then the sharks eat them. That would turn up inside the sharks. It's very interesting to me that the caffeine and the cocaine show up in the sharks. The cocaine in particular, because that doesn't have a very long residence time. So it may mean that those sharks recently ingested something that had cocaine in it, or some other organism that had already ingested the cocaine. That also indicates that it might be or that it might be so prevalent in the system that there's cocaine dropped in the water or people deliberately doing it to see what the sharks do.”

Dr Davis said further research should expand to other species such as conch, grouper and lobster and examine additional pollutants, including oil, to better assess the impact of human activity on marine ecosystems.