(WSVN) - Scientists want to know what is going on in the waters off the Florida Keys. That’s because fish there are behaving strangely and even dying. 7’s Heather Walker has tonight’s 7Investigates.

The videos are all over social media: Fish swimming in circles

Gregg Furstenwerth, diver: “I had no idea what it was. I mean, I saw the fish spinning and I was like, ‘What is it’ and, you know, at the time I thought it was hilarious.”

But diver Gregg Furstenwerth soon realized the fish was in trouble and other fish were also struggling.

Gregg Furstenwerth: “Then that was like, ‘What do you do?’ It’s alarming and sad and depressing. Just beyond anything I’ve ever seen in my life. And I’ve been in the water a lot.”

Gregg has been diving in the keys since 2021. For the past year, he’s seen all types of fish spinning and twirling.

Gregg Furstenwerth: “I see this every day. Every single day. I can go out and see the fish struggling and spinning and dying.”

The Florida Fish and Wildlife Commission says 27 species are now affected, primarily in the lower keys from Big Pine to Key West, including the critically endangered smalltooth sawfish. Many have grounded themselves. As of last week, 20 have died.

Gregg Furstenwerth: “It’s heartbreaking sitting there watching a live grouper for 2.5 hours die. I’ll tell you that. It’s not something that anybody wants to see.”

And no one knows why it’s happening.

FWC is working with Florida Gulf Coast University and others to find answers.

Mike Parsons, marine science professor, Florida Gulf Coast University: “The typical causes would be something like red tide or low oxygen in the water. That’s not the case here.”

Mike Parsons is a marine scientist at Florida Gulf Coast. He has been studying in the Keys for 15 years. This is the first time he’s ever seen something like this.

Mike Parsons: “One interesting thing about this is so many different fishes are being affected. So that led to our hypothesis that maybe it’s something in the water maybe dissolved in the water itself.”

When fish start spinning, it usually means there is some neurological impact on the fish.

Right now the professor says their best lead on a possible cause is a microscopic algae called gambierdiscus. It’s a naturally occurring toxin that is normally harmless. But recent tests show extremely high levels in the water.

Mike Parsons: “It does remain a mystery, but we are making some progress.”

Greg says they need to move quickly before things get worse.

Gregg Furstenwerth: “Nobody knows what this is. Nobody knows how to stop it.”

Greg and scientists hope whatever the problem is, they can find a solution to save the fish.

Heather Walker, 7News.


Please report abnormal fish behavior, fish disease, fish kills to FWC’s Fish Kill Hotline either through the web form (MyFWC.com/ReportFishKill) or by phone (800-636-0511).
Eating fish from these areas is not advised.
Swimming where there are dead fish is not recommended.


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