Dozens of species of fish, including endangered sawfishhave been spinning and swirling in the waters off the Florida Keys for months, but so far there appears to be no threat to humans, the director of a marine laboratory and aquarium said Monday.
“No abnormal water quality parameters have been identified by environmental health agencies that regularly monitor the waters,” Michael Crosby, president and CEO of Mote Marine Laboratory, told CBS News. “It appears to be some sort of agent in the water that only negatively impacts fish species.”
Mote Marine Laboratory is one of several groups partnering with the National Oceanic and Atmospheric Administration to contribute to the agency’s emergency response to the phenomenon.
Crosby said his group took tissue samples from live, but distressed, sawfish in hopes they could help scientists determine the cause of the spinning.
While officials widely use the terms spinning and whirling to refer to the abnormal behavior, each affected fish behaved slightly differently, Crosby said.
Fishing in the area remains open, the Florida Fish and Wildlife Conservation Commission advises against harvesting distressed or dead animals. It also states that it is not recommended to swim where there are dead fish.
What is causing the turnover and deaths?
Authorities don’t yet know what’s causing the strange behavior, but Crosby said it could be a toxin or a parasite.
“It almost seems like it’s a neurological response to some sort of agent,” he said. “I’m not yet at all sure what it is, (the) scientific community has not yet identified irrefutable proof.”
There are no signs of a transmissible pathogen and samples tested negative for bacterial infection, the Fish and Wildlife Conservation Commission said. Scientists also do not believe that dissolved oxygen, salinity, pH or temperature are the cause of these strange behaviors and deaths. Water samples also tested negative for Red Tide toxins.
Several aquariums and laboratories partnered with NOAA will house and rehabilitate sawfish, including the Mote Marine Laboratory.
The rescued sawfish will be under observation in quarantine facilities, according to NOAA. The goal is to release them into the wild once rehabilitated.
What types of fish are affected?
At least 109 sawfish were affected and 28 deaths were recorded, according to NOAA.
“We suspect total mortality is higher because sawfish have negative buoyancy and are therefore unlikely to float after death,” said Adam Brame, NOAA Fisheries sawfish recovery coordinator. “Given the limited population size of smalltooth sawfish, the mortality of at least two dozen sawfish could impact the recovery of this species.”
The sawfish, which can be found in shallow coastal waters, is a type of endangered stingray – a type of boneless fish, according to NOAA. Instead, sawfish skeletons are made of cartilage.
Sawfish can grow up to 16 feet long and weigh several hundred pounds. The affected sawfish measured between 7 and 14 feet in length, according to NOAA.
Florida officials say other types of rays and fish with bones are also affected by this strange rotation. Some of the species affected are: stingray, bonnethead shark, goliath grouper, gray snapper, gray triggerfish, lemon shark, nurse shark and scaled sardine.
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