Skip to Main Content
July 30, 2003
Bush River Blue-green algal bloom continues.

On Monday, July 28th, Maryland DNR returned to survey the Bush River where a blue-green algal remains active. The bloom, consisting mostly of Microcystis has discolored the water and has produced localized concentration areas but overall appears less intense than the continuing algal bloom on the Sassafras River (see HAB News from July 29, 2003: "Sassafras River Algal Bloom Conditions Intensify and Expand.").

A blue-green algal bloom was identified by Maryland Department of the Environment (MDE) personnel on July 23rd on the Bush River, an upper western shore tributary to the Chesapeake Bay. In an area where the algae were concentrated close to the shoreline from the winds and currents, algal concentrations of Microcystis were estimated at 1.6 million cells/ml. On July 28th, the bloom region was found to be patchy throughout the river and concentrations in one sample collected in the main channel contained 600 cells/ml. A sample was also collected for toxin analysis that will take approximately two to three weeks before we receive test results.

A photo of a Microcysitis bloom on the Bush River.

Although there have been no reported cases of human illness, people should take common precautions to reduce the risk of illness or discomfort related to blue-green algal blooms:

  • The public should not swim in areas where blue-green algae bloom is evident. Do not drink water from any area with appearance of a blue-green algae bloom.

    •
  • If contact is made with problem water, simply wash off with fresh water. In some cases, skin irritations may occur after prolonged contact. If irritations persist, see a physician or local health care provider.

    •
  • Keep pets and livestock away from bloom areas. Blue-green algal blooms may contain toxins that could be harmful or fatal to pets and livestock.

Blue-green algae naturally occur in tidal freshwater portions of the Chesapeake Bay and its tributaries. However, algal blooms may periodically use up oxygen, causing fish to suffocate and die. Affected waters may also appear as if a blue-green to yellow-green paint is floating on the surface of the water. Major blue-green algae blooms were last reported in the upper Bay region in 2000.

A Press Release regarding conditions on the Sassafras River was published by Maryland Department of the Environment July 22nd and may be referenced for further information on blue-green algal blooms in the upper Chesapeake Bay. A fact sheet on Microcystis and the 2000 bloom can be found on the Department of Natural Resources' website. Maryland Departments of Natural Resources and Environment will continue to monitor the situation and publish updates to the website as necessary. To report a fish kill or fish health related event, please call the Fish Health Hotline at (888) 584-3110, 24 hours a day.