About two weeks after hundreds of fish on Lake Apopka died, floating to the surface of the lake and concerning area residents and fishing enthusiasts, a reason for the fish kill event remains unclear, according to the Florida Fish and Wildlife Conservation Commission.
Testing remains ongoing. No evidence points to either an algal bloom or low dissolved oxygen levels in the water as the fish kill’s likely cause, per FWC, which also reports it received 31 fish kill reports for Lake Apopka between January 31 and February 11.
Cold temperatures can also trigger fish kills, especially if water temperatures drop suddenly or last for an extended period of time, according to FWC. Other common fish kill causes include disease, herbicides, and spills of sewage or petroleum.
Orange County resident Andy Braddock calls Lake Apopka, Florida’s fourth-largest lake, his “happy place.” Braddock says he spends lots of time fishing on the lake, and captured video of the fish kill event there after recently discovering the dead fish while out boating.
Like most lakes in Central Florida, Lake Apopka is polluted enough for state and federal agencies to consider it “impaired.” Restoration efforts over the years have led to some improvements, but Lake Apopka is still impaired by pollution from nutrients, like nitrogen and phosphorus, as well as pesticides, according to the Florida Department of Environmental Protection.
Some Floridians, including fishing enthusiasts who frequent Lake Apopka, are concerned the state’s herbicide strategy for aquatic plant management may be too aggressive. Herbicides are used to control the spread of invasive aquatic plants, like hydrilla, but some worry the chemicals in those herbicides may do more harm than good, particularly to fish and other wildlife.
RELATED: As pollution plagues Florida lakes, state spends millions to manage invasive plants
FWC is not currently applying any herbicide to Lake Apopka, according to agency data, but did apply herbicide to treat hydrilla there in 2023.
Some fish that washed up onto Lake Apopka’s south shore at the Oakland Nature Preserve are still decomposing, according to Nicole O’Brien, the preserve’s managing director. But no more dead fish appear to be floating up to the surface.
“It seems like the active event is over,” O’Brien said.
FDEP continues to analyze water samples FWC collected during the fish kill, and the St. Johns River Water Management District also collected water samples, per an FWC spokesperson. Staff with FWC also collected dead fish for analysis, but those necropsies so far haven’t yielded conclusive results.
