Florida Fish Are Mysteriously Dying After ‘Spinning and Whirling,’ and Scientists Can’t Explain It

The abnormal behavior has raised special concerns about the endangered smalltooth sawfish, an odd-looking ray with chainsaw-like teeth, as 28 of them have died

Large fish on a table with people standing above
Wildlife biologists are trying to figure out what's killing smalltooth sawfish and other species in Florida. Florida Fish and Wildlife Conservation Commission

Something strange is happening to fish off the coast of Florida.

At least 40 different species have been spotted “spinning and whirling” in the water near the Lower Florida Keys, and some of the fish have died, according to a statement from the National Oceanic and Atmospheric Administration (NOAA). So far, scientists can’t explain what’s causing this abnormal trend.

The affected creatures range “all the way from the very small bait-type fish, like pinfish, all the way up to things like groupers and even some stingrays,” says Dean Grubbs, a marine biologist at Florida State University, to NBC News’ Marissa Parra, Maria Piñero and Lora Kolodny.

Though the bizarre behavior is concerning across the board, wildlife biologists are particularly worried about how it has impacted the smalltooth sawfish (Pristis pectinata), an endangered species with a long, flat nose and sharp, chainsaw-like teeth.

More than 28 dead smalltooth sawfish had been recorded as of March 24, per NOAA. But the true death toll is likely even higher, because the bodies of these fish, which can grow up to 16 feet long, typically sink.

A total of 109 smalltooth sawfish have been observed spinning, including the 28 that ultimately died.

Craig Schertzer spotted a sawfish that had washed up in the tide between Big Pine Key and Marathon in early March. It was still alive, but it appeared to be struggling to get back to open water, according to videos Schertzer posted on social media.

“It was in such distress and there was nothing anybody could do,” Schertzer tells FOX 13 News’ Kimberly Kuizon.

Why are fish spinning to death in Florida?

It’s not clear how many smalltooth sawfish still exist in the wild in the United States, but “it is believed that the population is currently only a small fraction of its historic size,” according to a NOAA fact sheet. The creatures used to live in coastal waters between Texas and North Carolina but are now primarily found near Florida.

“Given the limited population size of smalltooth sawfish, the mortality of at least two dozen sawfish could have an impact on the recovery of this species,” says Adam Brame, the sawfish recovery coordinator for NOAA Fisheries, in the statement.

NOAA, in partnership with the Florida Fish and Wildlife Conservation Commission and local aquariums, now plans to launch its first-ever emergency response effort to try to save Florida’s smalltooth sawfish.

Ripley’s Aquariums, the Mote Marine Laboratory and Aquarium and Dynasty Marine Associates Inc. have offered to temporarily house wild sawfish in quarantine facilities until the cause of the mysterious behavior can be identified.

The logistics of the emergency response will be complex, because biologists have never attempted to rescue smalltooth sawfish before. They’re not sure how they will transport them, whether that’s towing them in a vessel or putting them into a sling, reports the Tampa Bay Times’ Max Chesnes.

“People do these rescues for sea turtles, dolphins and manatees all the time,” says Tonya Wiley, founder of Havenworth Coastal Conservation, a research group participating in the recovery effort, to the Tampa Bay Times. “But it’s never been done for a 14-foot sawfish before. We’re blazing a trail here.”

Already, wildlife officials have ruled out several potential triggers for the curious behavior, including bacterial infections, algal toxins, chemicals and communicable diseases. Staff with the Florida Fish and Wildlife Conservation Commission have also determined that temperature, salinity, pH and dissolved oxygen were not responsible for the deaths.

They’re continuing to analyze water samples and perform necropsies on dead fish in hopes of identifying the source of the issue. So far, the Florida Fish and Wildlife Conservation Commission has sent 12 smalltooth sawfish and individuals of other species to the University of South Alabama for further study.

“It almost seems as if it is a neurological response to some kind of agent,” says Michael Crosby, president and chief executive officer of Mote Marine Laboratory and Aquarium, to CBS News’ Aliza Chasan. “Not at all sure what it is yet, [the] scientific community has not identified a smoking gun as of yet.”

So far, whatever is causing the fish to behave oddly does not seem to be affecting humans.

Members of the public are encouraged to record videos and take pictures of any fish they see behaving strangely, then upload them to citizen science platforms like iNaturalist.

The Florida Fish and Wildlife Conservation Commission also asks people to report any and all smalltooth sawfish sightings—whether behaving normally or abnormally—via phone or email: [email protected] and 1-844-472-9347. Any sightings of dead fish or fish behaving abnormally can be reported to the commission’s Fish Kill Hotline at 800-636-0511.

“Public reports are an essential resource for our investigation into this event,” according to the commission.

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