Endangered sawfish, rescued in the Florida Keys, dies during rehabilitation

A promising development in an ongoing fish kill in the Florida Keys took an unfortunate turn this week when a sick endangered smalltooth sawfish died after having been rescued from the island chain’s waters and taken to Sarasota for rehabilitation.

Scientists at Mote Marine Laboratory had to euthanize the shark-looking ray on Thursday because its health condition continued to deteriorate, it was announced Friday.

“It was always our cautious hope to be able to utilize the best available science for the rehabilitation and release of the sawfish,” Dr. Michael P. Crosby, president & CEO of Mote Marine Laboratory & Aquarium, said in a statement.

“Although heartbreaking, this outcome was not surprising. Mote’s several decades of active rescue and rehabilitation efforts have taught us that these efforts aren’t always successful in fully rehabilitating compromised stranded animals.”

The sawfish was rescued from the shallow waters off Cudjoe Key in the Lower Keys on April 5 after members of the public reported that it was swimming in circles, which is a behavior sick sawfish have been exhibiting in the Keys since the beginning of the year.

Since Jan. 29, the Florida Fish and Wildlife Conservation Commission says 45 sawfish have been found dead in the Keys. That creates a serious situation for the species since the Keys are one of the few places you can still find them in the wild. Their habitat once ranged from Texas to North Carolina, but sawfish populations have greatly decreased, and they were placed on the Endangered Species List in 2003.

Alarmingly, the spinning behavior seen in smalltooth sawfish in the Keys has also been reported in several other species that scientists believe is linked to a fish kill first reported in November.

Biologists from Mote, academia, National Oceanic and Atmospheric Administration, FWC and nonprofits like the Bonefish and Tarpon Trust have been working continuously to get to the bottom of what is causing the phenomenon, which is mostly confined to the Lower Keys from Big Pine Key to Key West.

The FWC has received more than 460 reports to its hotline dedicated to the Keys fish kill.

So far, red tide toxins have been ruled out based on water samples taken from the impacted area.

And necropsy data taken from dead fish samples so far have not turned up any communicable pathogens and the fish were negative for bacterial infections, according to the FWC.

Dissolved oxygen levels, salinity, acidity and temperature are also not suspected to be the causes of the fish kills or spinning, according to the FWC.

State scientists have also conducted water tests for a variety of chemicals, “which were either not detected or were below normal limits,” the FWC said on its site dedicated to the fish kill.

For the erratic, spinning behavior, scientists have speculated it may be related to a toxin called gambierdiscus, which causes a food-borne illness called ciguatera in people who eat infected fish. It’s common in the Keys because it grows as a micro algae on the coral reef. Basically, smaller fish eat the algae, and the toxin gets passed up the food chain right up to people who eat larger predator fish.

In the meantime, the FWC will conduct a necropsy to try to determine what sickened the sawfish in Mote’s care.

“Samples will be collected and sent to various labs for further analysis,” Mote said in a statement. “Necropsies do not always determine a cause of death, and it could take weeks to months to get a full picture of the animal’s condition.”

To report a sick sawfish, call (844) 4-SAWFISH (844-472-9347) or email sawfish@myfwc.com.

Report abnormal fish behavior and fish kills to the Florida Fish and Wildlife Conservation Commission’s Fish Kill Hotline at (800) 636-0511 or MyFWC.com/ReportFishKill.