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  • Writer's pictureDave LeGear

Pharmaceutical Contaminants Discovered in Florida Redfish

Blood sampling Charlotte Harbor

(Blood sampling Charlotte Harbor Andy Distrubell (pc-JoEllen Wilson)

Our friends at BTT (Bonefish & Tarpon Trust) sent Flats Nation the following recent findings to help bring some more exposure to them...

Pharmaceutical Contaminants Discovered in Florida Redfish

Miami, FL – A year-long study by Florida International University (FIU) and Bonefish & Tarpon Trust (BTT) has discovered pharmaceutical contaminants in the blood and other tissues of redfish in Florida waters. This research follows a similar study of bonefish in the Florida Keys, which revealed high levels of pharmaceutical contamination. This new study shows that these waterborne contaminants are a concern statewide.

“The results underscore the urgent need to modernize Florida’s wastewater treatment systems,” said BTT President and CEO Jim McDuffie. “Human-based contaminants like these pose a significant threat to Florida’s recreational fishery, which has an annual economic impact of $13.9 billion and directly supports more than 120,000 jobs.”

Scientists or volunteer guides and anglers sampled redfish in nine of Florida’s most important estuaries: Pensacola, Apalachicola, Cedar Key, Tampa Bay, Charlotte Harbor, Florida Bay, Northern Indian River Lagoon (IRL), St. Augustine, and Jacksonville.

Sampled fish Tampa Bay

(Sampled fish Tampa Bay Andy Distrubell - Capt. Dustin Pack (pc-Dustin Pack)

Similar to the results of the previous bonefish study, pharmaceuticals were found in all of the estuaries sampled, with an average number of 2.1 drugs per fish and a maximum of five. Only seven out of the 113 sampled fish had zero drugs in their system. On average, 25.7 percent of the fish exceeded a level of pharmaceuticals considered safe, which equates to one-third of the therapeutic levels in humans.

“These studies of bonefish and redfish are the first to document the concerning presence of pharmaceuticals in species that are important to Florida's recreational fisheries,” said Dr. Jennifer Rehage, FIU professor and the study’s lead researcher. "Given the impacts of many of these pharmaceuticals on other fish species and the types of pharmaceuticals found, we are concerned about the role pharmaceuticals play in the health of our fisheries. We will continue this work to get more answers to these concerning questions.”

Sampled fish Anna Maria Island

(Sampled fish Anna Maria Island Andy Distrubell (pc-David White)

Cardiovascular medications, opioid pain relievers, and psychoactive medications were most commonly detected (from highest to lowest detections). The antiarrhythmic medication flecainide and the opioid pain reliever tramadol were detected in over 50 percent of the redfish. The antipsychotic medication flupentixol was detected above safe levels in one in five of the redfish samples. These are very concerning levels of exposure for redfish.

Approximately five billion prescriptions are filled each year in the US, yet there are no environmental regulations for the production nor disposal of pharmaceuticals worldwide. Pharmaceutical contaminants originate most often from human wastewater and are not sufficiently removed by conventional water treatment. They remain active at low doses, can be released constantly, and exposure can affect all aspects of fish behavior, with negative consequences for their reproduction and survival. Pharmaceutical contaminants have been shown to affect all aspects of the life of fish, including their feeding, activity, sociability, and migratory behavior.

“Florida is a leader in addressing water quality issues and wastewater infrastructure, including converting septic systems to sewage treatment,” said Kellie Ralston, BTT’s Vice President for Conservation and Public Policy. “The results of this study indicate that there are additional opportunities for improvement by retrofitting existing wastewater treatment plants with innovative technologies, like ozone treatment, to remove pharmaceuticals and requiring such technology on new wastewater facilities.”

Click Here to view a summary of Redfish Pharmaceutical Contaminants Study’s findings.

About Bonefish & Tarpon Trust

Bonefish & Tarpon Trust's mission is to conserve bonefish, tarpon, and permit—the species, their habitats, and the larger fisheries they comprise. BTT pursues this mission across the southeastern US, the Gulf of Mexico, and the Caribbean Sea through science-based conservation, education, and advocacy. Learn more at

About Florida International University

Florida International University is a Top 50 public university that drives real talent and innovation in Miami and globally. Very high research (R1) activity and high social mobility come together at FIU to uplift and accelerate learner success in a global city by focusing on the areas of environment, health, innovation, and justice. Today, FIU has two campuses and multiple centers. FIU serves a diverse student body of more than 58,000 and 270,000 Panther alumni. U.S. News and World Report places dozens of FIU programs among the best in the nation, including international business at No. 2. Washington Monthly Magazine ranks FIU among the top 20 public universities contributing to the public good.

We want to thank our friends at BTT (Nick and Dr. Ross) for working with Flats Nation to help bring more exposure to their findings so we can all use this Data and Knowledge to help improve and logically manage our Flats and Nearshore ecosystems! We are looking forward to more Projects and Podcasts with them in the future...

We have come a long way since I was a young man, and "Rivers caught on Fire!" This while many seem to forget the actual economic value that our Recreational Fishing brings in Florida (alone) and all part of our growing series and Tag Line here on Flats Nation that we started, "No Fish / No Florida!" and to read more about that most important aspect when it comes to securing the attention it deserves by our elected leaders, click Here 😊

In the meantime,

We invite you to take in a few Flats Nation Podcast Episodes to help "Scratch that Fishing Itch" when working or traveling and you just cannot hitch up the Skiff and go, on these links:

Our main podcast page works great for your mobile device since it will stream on your phone/tablet. It can be found by clicking Here.

Our new Flats Nation YouTube Channel can be found by clicking Here and sharing them with family and friends if you find them Entertaining and Educational! We have some great guests in the works and planning stages on a wide range of topics and product coverage soon.

Also, you can check out some new Flats Nation Merch and Swag to enjoy. 😎

Tight Lines, and God Bless!

Dave and the Team

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