Drugged fish: Drug cocktail contaminating ocean food chain | Fish – Advice Eating

NNicknamed “grey ghosts” for their shiny silver scales, remarkable camouflage and speed, bony fish can swim up to 40 mph. Protected by catch-and-release laws in the US, this species is revered by anglers around the world, many of whom visit Florida in search of the elusive fish.

But evidence points to a precipitous decline in bonefish numbers in South Florida. Researchers estimate that populations have declined by more than 50% in four decades.

dr Jennifer Rehage, a fish ecologist and associate professor at Florida International University (FIU), has spoken to many anglers about the disappearance of fish from Florida’s seagrass beds: “They said to me, ‘I’ve been fishing [bonefish] all my life and i can’t find her. I haven’t seen a Bonefish in five years and it’s driving me insane.

For the past three years, Rehage has been leading a study to find out why and has discovered something that might help explain it: pharmaceuticals.

A bony fish that swims in seagrass flats.
A bony fish in seagrass flats. Human drugs have been found to alter the behavior of fish as they accumulate in aquatic environments. Photo: FtLaudGirl/Getty/iStockphoto

Of the 93 teleosts she and her team sampled, all tested positive for at least one drug, including heart drugs, opioids, antifungals and antidepressants, according to the study published in February.

In 56% of the fish, the researchers detected pharmaceutical amounts at concentrations “above which we expect adverse effects,” according to the study. A bonefish harvested in Key West tested positive for 17 drugs — eight of them antidepressants that were up to 300 times the human therapeutic level. Pharmaceutical exposure in bonefish in South Florida was “widespread and of concern,” the study concluded.

The researchers also studied 125 animals that hunted bonefish, including shrimp, crabs and small fish. Each contained an average of 11 pharmaceutical contaminants, suggesting that contamination is not limited to bonefish.

While more is known about the potential impacts of pharmaceutical pollution in freshwater, the effects on the ocean have been far less studied. There is still not enough information to directly link teleost declines to drugs, but “the potential for drugs to be a problem [for fish in the sea] is impressive and worrying,” says Rehage.

In the US alone, nearly 5 billion medications are prescribed annually, and the average American has about 12 prescriptions a year. Pharmaceuticals get into water through a variety of routes, including manufacturing and stormwater runoff, but human and animal wastewater is a major culprit — particularly what people send down the toilet.

The specific health consequences of pharmaceutical contamination of marine life are not fully understood, but there is evidence of numerous adverse effects.

“[It] can have several consequences, mainly on the behavior of fish, but it can also affect their reproductive capacity and endocrine system,” says Elena Fabbri, professor at the Faculty of Biological, Geological and Environmental Sciences at the University of Bologna in Italy.

In 2013, scientists from Umeå University in Sweden – which collaborated with the FIU on the Bonefish study – found that wild bass were less anxious and more antisocial when exposed to anti-anxiety drugs that could interfere with feeding and breeding. A 2016 study from the same university found that salmon exposed to this drug swam faster and exhibited riskier behavior. Exposure of crayfish to antidepressants has been linked to altered behavior that increases their boldness and the time they spend foraging, potentially making them more vulnerable to predation.

There are three main ways that wastewater enters the ocean, says Rachel Silverstein, director of environmental organization Miami Waterkeeper: wastewater pollution, discharge of treated wastewater into the ocean, and defective septic tanks. All of these were big problems in Florida. In 2020, 212 million US gallons (800 million liters) of wastewater entered Fort Lauderdale’s waterways.

“Although most contaminants are screened out in wastewater treatment plants, it’s very difficult to remove some of these drugs from the water,” says Silverstein. Additionally, more than half of Miami-Dade County’s septic tanks aren’t filtering waste properly due to rising sea levels, posing a threat to the environment and public health, she says.

People walk past a sign on a beach warning of sewage pollution
A sign warns Miami Beach visitors of sewage pollution. In 2020, 800 million gallons of wastewater were spilled onto Fort Lauderdale’s waterways. Photo: Reuters/Alamy

Silverstein sees the FIU’s study as “further evidence that we need to make urgent changes to improve our infrastructure so that we can continue to live in this region and protect our economic and environmental interests.”

The problem is not limited to Florida. Experts say that the sewage infrastructure urgently needs to be improved worldwide to remove pharmaceuticals before they reach the ocean.

Implementing an additional step in wastewater management known as “ozonation” could help, Rehage says. The technique adds ozone to the water to remove contaminants often overlooked in traditional wastewater treatment, including pharmaceuticals and pesticides. But too few countries are converting plants to this step, she says, pointing to Switzerland, Sweden and Germany as the only countries “that are actually dealing with this pharmaceutical topic”.

Improved wastewater management is important, but the pharmaceutical industry itself also has a responsibility to address the problem by exploring more environmentally friendly alternatives, says Fabbri. “We can’t ban these substances because we need them, but we could favor or push the pharmaceutical industry to find more environmentally friendly alternatives.” This could include making medicines that break down more quickly in the environment.

There are policy moves to learn more about the impact of drugs on waterways. For example, in 2019 the EU adopted a “strategic plan” to address the risks of pharmaceutical pollution. However, many of these initiatives are more focused on impacts on freshwater environments.

As further research points to the effects of pharmaceuticals in the sea, Fabbri says: “We must continue to publish on this issue to inform regulators that these regulations are also needed in marine environments.”

For now, researchers say there’s still a long way to go in the US. “Controlling chemicals entering our environment has always been reactive,” says Aaron Adams, director of science and conservation at Bonefish & Tarpon Trust, the conservation organization that commissioned the FIU study.

“There are no legal limits for controlling pollution from pharmaceuticals during manufacture, use or disposal,” the report said.

Nick Castillo, a graduate student at FIU and co-author of the study, says standardized metrics are needed to assess the effects of drugs on exposed organisms. At present, he points out, these “antiquated” environmental regulations would tend to ignore drugs “because they are non-lethal”.

Studying the effects of drugs in waterways has historically focused heavily on freshwater, says Rehage: “This is one of the first studies to cover seacoastal environments and over a large area to show that drugs are ubiquitous.”

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