FWC determines fungus caused St. Johns fish kill
Tuesday, November 09, 2010
Media contact: Carli Segelson, 727-896-8626
Biologists with the Florida Fish and Wildlife
Conservation Commission's (FWC) Fish and Wildlife Research
Institute have determined the cause of a recent fish kill in the
St. Johns River. Testing confirmed that a fungus led to the fish
die-off that occurred in the river in mid-October.
The FWC received reports of dead fish and fish with
ulcers beginning Oct. 20. Reports came from an area of the river
just south of Interstate 95 near Jacksonville and as far south as
Green Cove Springs. The FWC responded by analyzing dead fish and
water samples from the area.
FWC biologists suspected that a fungus called
"Aphanomyces invadans" caused an infection, which produced
ulcer-like lesions and the eventual death of shad, mullet and
menhaden in the St. Johns River. The National Oceanic and
Atmospheric Administration confirmed the FWC's findings when it
conducted specialized testing on diseased-fish samples provided by
This fungus, which is a type of water mold, occurs
naturally in estuaries and freshwater systems in Florida -
generally in water bodies with lower salinity levels. Scientists
have confirmed that it causes an ulcer-forming disease in estuarine
and freshwater fish worldwide. This is not the first time that fish
with these types of ulcers have been observed in the St. Johns
River. Reports of similar incidents date back to the late 1970s.
However, biologists have no evidence that there is a connection
between this fish kill and the large-scale fish kill that occurred
in the river earlier this summer.
FWC scientists track the location and extent of
fish kills in natural water bodies. This enables them to monitor
the development of serious problems in an ecosystem that might
require investigation or restoration measures.
As a reminder, according to the Florida Department
of Health, harvesting distressed or dead animals for consumption is
not advised under any circumstances. More information is available
Residents can report fish kills in natural water
bodies to the FWC through MyFWC.com/Contact, or call the FWC Fish
Kill Hotline at 800-636-0511.