Cocaine Found In Sharks Leaves Scientists 'Dumbfounded'

Scientists are blown away after finding significant traces of cocaine in a small sample of sharks from the waters off the coast of Rio de Janeiro.

In a study published online last week, researchers reported the presence of the unfiltered drug in the liver and muscle tissues of all 13 Brazilian sharpnose sharks they tested.

Rachel Ann Hauser-Davis, a co-author of the study and a biologist at the Oswaldo Cruz Foundation, said her team was “actually dumbfounded” by the discovery.

“We were excited in a bad way, but it’s a novel report,” she told The New York Times . “It’s the first time this data has ever been found for any top predator.”

Though past research has detected cocaine in an array of smaller ocean species, like mollusks and crustaceans, the amount seen in the sharks was 100 times higher than that found in previous studies of marine wildlife, suggesting chronic exposure to the substance.

(Sharpnose sharks are relatively small themselves. While some of their more fearsome relatives, like great whites, can weigh tons, one study of Brazilian sharpnoses found that they weighed up to 6 or 7 pounds.)

A researcher holds a young male Atlantic sharpnose shark, a close relative of Brazilian sharpnoses, near the Outer Banks of North Carolina.

According to Hauser-Davis, some think the cocaine could have made its way into the water via illegal drug labs near the coast or traffickers dumping the illicit substance into the ocean. But the biggest contributor is perhaps less lurid.

“We feel that the major source would be excretion through urine and feces from people using cocaine,” Hauser-Davis told the Times.

And while the discovery of cocaine in sharks is making headlines, researchers say the presence of the drug points to larger questions about all kinds of waste contaminating Earth’s waters.

“Cocaine gets people interested,” environmental engineer Tracy Fanara told the Times. “But we have antibiotics, antidepressants, pharmaceuticals, sunscreen, insecticides, fertilizers. All of these chemicals are entering our ecosystem.”