BALTIMORE (AP) - A mahogany tide is turning the Chesapeake Bay a reddish brown in places, lowering oxygen levels and killing fish.

Jay Apperson, a spokesman for the Maryland Department of the Environment, says state officials began monitoring early this year because of the warm winter and heavy rains last year that washed pollution into the bay. Apperson says algae blooms have been tracked since March, and have been particularly noticeable recently in the Patapsco River basin near Baltimore and the western side of the Bay Bridge near Annapolis.

Apperson says about 6,000 fish have also been found dead this week in Marley Creek near Glen Burnie. Testing found very low oxygen levels believed to have been caused by an algae bloom.