State Investigating Widespread Fish Kill in Maryland Waters

Hundreds of dead fish are dead and floating from Fells Point in Baltimore harbor into the Chesapeake Bay, and state officials aren’t sure why. 

Among the casualties are Atlantic menhaden and shad. Investigators told the Baltimore Sun up to 1,000 fish could be dead, but some experts suspect more have died off.

"There are fish spread for miles across the river — from the Key Bridge to the Inner Harbor," John Tapscott, an educator for the Annapolis-based bay foundation, told the Sun. He saw the fish while aboard the Snow Goose, which the group uses to take kids on educational cruises from Baltimore harbor.

Warmer weather typically causes a fish kill in local waters each year, but this year’s is unique because it's earlier than usual. While pollution and disease are quick killers, most die-offs are due to a lack of oxygen in the water. That’s typically caused by algae blooms, which suck up oxygen and suffocate fish. Fertilizer, animal waste and sewage can help algae grow.

While the state didn’t find a link between this fish kill and low oxygen levels or algae blooms during its preliminary investigation, heavy rains that brought storm runoff could have provided fodder for an algae bloom, William C. Dennison, a vice president of the University of Maryland Center for Environmental Science, told the Sun.

The warmer temperatures and sunshine that followed would’ve made for the “perfect recipe” for a fish kill, Dennison said.