The New York State Department of Environmental Conservation (DEC) today announced a common parasite and a bacteria contributed to a large fish die-off in Seneca Lake last week. DEC Fisheries staff collected samples of Alewife, a forage fish, after being notified on June 20, about the lake-wide die-off.

Samples were analyzed for DEC by Cornell University College of Veterinary Medicine and determined to be caused by Chilodonella and Aeromonas hydrophila. Chilodonella is a common parasite found in most waters. Aeromonas hydrophila is a bacteria that causes a disease in fish called Motile Aeromonas Septicemia. Neither the parasite nor bacteria have human health impacts.

A similar die-off of alewives attributed to Chilodonella occurred in Seneca Lake in 2017. No appreciable impact to the Alewife population was noted in the most recent incident. DEC is continuing to monitor the fishery.

DEC encourages anyone that encounters a fish kill in DEC Region 8 to contact Regional Fisheries staff at (585) 226-5343 or fwfish8@dec.ny.gov. Obtaining samples shortly after a fish die-off can better the chances of determining the cause.