Thousands of dead fish, along with decomposing algae, are causing a stench to emanate from the Inner Harbor and the waters off Canton, and a state official said yesterday that it might take at least a week to clear.
The stink - and the dead fish - are the result of an algae bloom, or a "brown tide." State environmental officials have been investigating the fish kill since Sunday.
The nutrient-rich harbor had a recent large bloom of microscopic algae that turned the water rust brown, said Charles Poukish, environmental program manager for Maryland Department of the Environment. When water exceeded 70 degrees last weekend, the algae died. As the algae decomposed, it depleted the oxygen on the surface of the water, causing at least 7,000 fish to die, Poukish said.
"The bottom line is, there is no dissolved oxygen in the water column," Poukish said.
Most of the dead fish were Atlantic menhaden, although pumpkinseed sunfish, Atlantic croaker, American eel and white perch also died.
"It's a pretty strong stench," Poukish said.
The city Department of Public Works has been on the water for the past few days, using boats and nets to pick up the fish carcasses. The dead fish, which are collecting in the water near Canton, are being buried in a landfill.
"This is very odd. I work in this area, and I've never seen these fish dead," said Michael Byrd, a city maintenance worker. "Even before I saw the fish, I said, 'What's that smell?' It's unbearable."
Ken Harper, who has lived in Fells Point since 1992, was taking a walk along Thames Street yesterday when he noticed the smell. "Those dead fish and the fish odor are not normal," he said.
Maureen O'Connor saw the floating carcasses during her morning run Monday along the Canton waterfront.
"I've been away for a week. And I went running and I said, 'What is that smell?' And I saw all the little silver fish. I was shocked," she said. "I was so happy to be back in Baltimore and go on my little run, and I see all these dead fish. It's horrible."
The MDE has collected fish and water samples, though Poukish said he is pretty sure the algae bloom caused the fish kill.
Poukish said the last time the Inner Harbor had a fish kill of this scale was five or six years ago.
The water will return to normal through tidal flushing and wind, which helps reoxygenate the water. But with an overabundance of nitrogen and phosphorous in water, conditions are ripe for another algae bloom, Poukish said.
See related video at baltimoresun.com/fishkill