How Dolphins' Fish Diet May Help Detect Potential Threats To Floridians' Health

Jul 28, 2014

Credit FAU's Harbor Branch Oceanographic Institute via twitter

A study linking Floridians’ seafood consumption, dolphins, and increased levels of mercury is leading researchers to say dolphins may be the key to identifying public health risks in humans.

On average, Floridians consume more seafood than the general U.S. population. And, human exposure to mercury tends to come from the consumption of fish and shellfish. Too much could become a health hazard.

So, when researchers at Florida Atlantic University’s Harbor Branch Oceanographic Institute found high levels of mercury in Atlantic bottlenose dolphins living in the Indian River Lagoon, they decided to look into the matter.

Adam Schaefer—an epidemiologist for the Florida Atlantic University’s Harbor Branch Oceanographic Institute—is one of the lead scientists on the study linking fish consumption and elevated mercury levels in humans.
Credit Sascha Cordner / WFSU-FM

“And, that raises some serious questions about the potential risk of exposure in humans who utilize the lagoon who fish and consume seafood from the area,” said Adam Schaefer, an epidemiologist for FAU’s Harbor Branch.

Schaefer is also one of the lead scientists on the project. In addition to surveying dolphins living in the Indian River Lagoon, his team studied hair samples from more than 130 Florida residents who live in the area.

They found those who eat locally-caught seafood three times a week or more are more likely to have a mercury concentration that was higher than the recommended daily dose set by the federal Environmental Protection Agency.

“It’s a really conservative number. And, it’s probably not, to be honest, necessarily up to the threshold of acute clinical disease,” added Schaefer. “But, in the U.S., what we’re more concerned about, when it comes to mercury exposure is actually pregnant females, and the developing fetus in young children because primarily, the effects of exposure to mercury are neuro-developmental. So, you see things like delays in fine motor skills, development, and speech.”

Schaefer says it’s one of the first studies to show the association between a sentinel species, like the dolphins, and humans to give warning signs about potential threats to human health.

Meanwhile, according to the Florida Department of Environmental Protection’s website, there are some fish safe for unlimited consumption, while others should be limited to a single serving per week.

For more news updates, follow Sascha Cordner on Twitter: @SaschaCordner.