Arkansas Game and Fish Commission received reports Friday evening (May 11) of about 200 dead or dying white bass on Lake Maumelle with yellow sores on them. AGFC staff worked with staff from Central Arkansas Water (CAW) to clarify reports of dead fish and obtain samples of dead fish. After further investigation it was determined that the species affected were mostly White Bass and Gizzard Shad, however, some Largemouth Bass and Freshwater Drum mortalities were also observed. The AGFC Fish Pathologist obtained a sample of dead fish Friday night.
The sores on the fish were a fungus called Saprolegnia that is common in winter and appeared to be healing. However, the stress of recovering from the fungus along with spawning stress and rapidly changing conditions on the lake likely caused the fish mortalities. Runoff from heavy rains during the week caused a drop in dissolved oxygen levels, pH, and water temperatures Thursday evening and Friday morning. Water temperatures fell from a high of 75 degrees Fahrenheit to 65 degrees in 18 hours, and during that time dissolved oxygen levels fell about two milligrams per liter. Levels of pH also reportedly fell during the same time span. Therefore, it was determined that the cause of the kill was natural, and due to the fish being stressed from spawning and a natural fungus along with a rapid change in water temperature, dissolved oxygen, and pH.
The kill was relatively small considering the size of the lake and we do not expect any impacts on the total number of fish in the lake. We appreciate the help of CAW staff in determining the cause of the kill and will continue to work with CAW on fisheries management at Lake Maumelle.