Eastern Baltimore County fish kill, December 26.

The Maryland Department of the Environment (MDE) investigated a large fish kill in the upper Gunpowder and Bird rivers near Joppatowne, MD (Harford/Baltimore Counties) on December 19, 2016. A follow-up investigation was performed on December 26, 2016, followed by periodic field observations during the month of January 2017. 

The results of the investigation indicate Karlodinium veneficum, a toxin producing saltwater algae, pushed remarkably far into the freshwater end of the Chesapeake Bay estuary in 2016.  As a consequence, a localized population of freshwater fish was adversely affected by a toxic algae species that is more commonly observed in higher saline water.  These results indicate that the fish were subjected to a lethal combination of karlotoxin and salinity stress that interfered with their respiratory system (i.e. gill function).

Anyone with information on fish kills or with other concerns on environmental matters involving the Chesapeake Bay or its tributaries should call the Bay environmental hotline at 877-224-7229.​