Overview
- State and federal monitors recorded unprecedented surface readings on July 4, with a Maryland Department of the Environment biologist noting 94°F and USGS sensors peaking at 98.4°F at the Little Falls site.
- Officials documented a fish kill spanning about 14 miles between White's Ferry and Violette's Lock with most carcasses identified as golden redhorse suckers.
- Scientists say the primary mechanism was reduced dissolved oxygen in the warm water, which reduces oxygen available to fish and increases physiological stress.
- The Maryland Department of the Environment reported no evidence of a chemical spill or pollution causing the mortality while laboratory testing and field surveys continue.
- The event coincided with consecutive record air temperatures across the region, including a 103°F Washington, D.C. reading, and comes as officials track related heat-linked health impacts such as at least 29 preliminary deaths reported in New Jersey.