Fish kill in Baltimore's Herring Run Park

City officials said Thursday they are investigating a fish kill in a Northeast Baltimore creek that flows through Herring Run Park, where users of the park and streamside trail expressed dismay.

"This is ridiculous," said Donald Cooper, who stopped while riding his bike to peer at the dead fish littering the stream bottom beneath the Harford Road overpass.

Cooper, 52, who lives nearby, said a couple days before, he'd brought his nephew to the park to see the fish, which he said then were "swimming all over the place...Now they're all dead."

David Flores, the Baltimore Harbor Waterkeeper, said a woman reported the fish kill to him late Thursday morning. When he got there around noon, Flores said he found "hundreds and hundreds" of minnow-sized fish and even some large foot-long suckers belly up.

"American eels are struggling to breathe, or basically beaching themselves on stream banks to get out of the water," he said when he contacted The Baltimore Sun.

Flores said he tracked dead and distressed fish up Tiffany Run, a tributary of Herring Run, until he came to a point where the stream is buried, emerging from a large outfall by Lake Montebello.

Though it wasn't immediately clear what killed the fish, Flores said it likely was an illicit discharge into a storm drain or into a stream. Sewage leaks and other discharges, either accidental or intentional, are a chronic problem rendering the city's waters unfit for people and in some cases even fish.

Herring Run empties into Back River, which along with the Patapsco River are the Chesapeake Bay's most degraded tributaries, according to the latest report from the University of Maryland.  Herring Run's 30-square-mile watershed drains densely developed Northeast Baltimore and portions of Baltimore County, as far north as Towson.  The stream and its tributaries have long been impaired for fecal bacteria, nutrients and sediment.

Flores said the woman who reported the kill to him said she smelled chlorine; while he detected an acrid odor himself, Flores said he could not identify it. Chlorine is used to make drinking water safe for humans to consume, but it is highly toxic to fish.

The city's Montebello water treatment plant is near there, but Flores said he understands Tiffany Run is fed by a large underground network of storm sewers there that drain land as far west as York Road.

Jeffrey Raymond, spokesman for the city Department of Public Works, said the cause of the kill is under investigation.  But he said investigators found low levels of chlorine and ammonia in stream water samples taken Thursday afternoon. The spokesman said that would suggest the fish likely weren't killed by a discharge of chlorinated city water or of raw sewage, another chronic problem in city streams.

UPDATE: Raymond said city investigators found dissolved oxygen levels normal  and no algae noticeable in the area of the fish kill. Large algae blooms often are linked to fish kills, as the aquatic plants consume oxygen in the water when they die and decay, thus suffocating the fish.