Endangered sawfish ‘whirling and spinning’ to death in Florida, baffling experts

Endangered fish are dying in droves by throwing themselves — “whirling and spinning” — onto the beaches of South Florida, leaving experts mystified.

Dozens of smalltooth sawfish have been found dead in the Lower Florida Keys, prompting baffled scientists to launch an “emergency response” to solve the erratic behavior.

The National Oceanic and Atmospheric Administration said Wednesday that the investigation efforts are unprecedented.

“If the opportunity presents itself, this would be the first attempt ever to rescue and rehabilitate smalltooth sawfish from the wild,” Adam Brame, NOAA Fisheries’ sawfish recovery coordinator, said in a statement.

“It’s important to note that active rescue and rehabilitation are not always effective in saving stranded animals. However, it can still give us critical information to learn about the nature of the distress.”

The smalltooth sawfish — named for their elongated, flat snout that contains a row of teeth on each side — are mainly found in southwestern Florida and the Keys island chain as their habitats shrink and have been listed as an endangered species since 2003.

The rare fish seemingly began killing themselves in January, when state wildlife officials began documenting the “unusual mortality event.”

As of Wednesday, at least 109 sawfish have been affected, 28 of whom have been killed. Hundreds of other fish across other species have been affected.

“We suspect that total mortalities are greater, since sawfish are negatively buoyant and thus unlikely to float after death,” said Brame.

“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.”

Among the erratic behavior, the sawfish have been documented “spinning and whirling,” according to the Florida Fish and Wildlife Conservation Commission.

The cause of the bizarre behavior remains a mystery.

According to state officials, the sawfish necropsies have shown no signs of pathogen or bacterial infections, nor problems with low water oxygen levels or contaminants such as chemicals, or toxic red tide.

It’s also not clear if the deaths and odd behaviors are related to a lengthy summer heat wave in Florida waters experts say was driven by climate change. The superheated waters caused other marine damage, such as coral bleaching and the deaths of other ocean species.

Marine experts are rushing to find the cause of the mortality event, and are working to rescue and rehabilitate the sawfish already affected at quarantined facilities.

All rescued fish will be returned to the wild after rehabilitation.

Officials are asking the public to report any erratic behavior they witness.