An extreme heat wave pushed temperatures in the Potomac River to record highs this past Fourth of July, causing a large-scale fish kill spanning approximately 14 miles, officials reported. The river north of Little Falls, Maryland, registered a water temperature of 94 degrees Fahrenheit on July 4, according to a biologist with the Maryland Department of the Environment. Data from the U.S. Geological Survey (USGS) indicated that water temperatures peaked even higher, reaching 98.4 degrees Fahrenheit.
These readings represent the warmest temperatures ever recorded at this site since record-keeping began in 1988, according to the FOX Forecast Center. The fish kill extended between Whites Ferry and Violette’s Lock in Montgomery County, Maryland.
Officials identified golden redhorse suckers as the most abundant species among the deceased fish. Scientists attributed the significant number of deaths to the extreme water temperatures creating stressful conditions for the fish. Warmer water holds less dissolved oxygen, which is essential for aquatic life. A Maryland Department of the Environment spokesperson stated that there was no evidence of a chemical spill or pollution in the affected area.
This event occurred amidst a severe heat wave across the East Coast. Nearby Washington, D.C., experienced three consecutive days of record-high temperatures, including a new Independence Day record of 103 degrees Fahrenheit. In New Jersey, health officials preliminarily linked at least 29 deaths across several counties to the extreme heat.