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Hydrilla and AVM-affected watersheds in the U.S. southeast

First introduced to the United States as an aquarium plant, hydrilla might now be considered the kudzu of the lakes across the Southeast. Its aggressive stems can grow up to an inch a day and extend 20 to 30 feet into dark waters where many native plants can't grow. 

But aside from its invasive effects in our waters, hydrilla are also host to a cyanobacteria, Aetokthonos hydrillicola, that has been linked to a disease in waterfowl. The disease, avian vacuolar myelinopathy (AVM), is a fatal neurological disease most often found in eagles and coot, but has also been found in a variety of other birds.

Warnell professor Susan Wilde was the first to make this connection, determining that the underside ot hydrilla leaves host A. hydrillicola, a cyanobacteria that produces a toxin passed to waterfowl from fish, who feed off the affected hydrilla. This toxin causes AVM.

First reported in 1994, AVM has caused the death of more than 100 bald eagles and thousands of American coots at dozens of sites from Texas to North Carolina. Warnell graduate student and research assistant Wesley Gerrin created this map to identify the watersheds where hydrilla exists, as well as places where A. hydrillicola has been verified, and to which degree.

You may also use this Google map to zoom in on particular watersheds.


map of AVM-affected bodies of water

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