Lower Eastern Shore (Eastern Bay to Choptank River) experienced widespread algal blooms; area fish kills investigated. |
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Algal blooms of the possibly-toxic dinoflagellate Karlodinium micrum were investigated by Maryland Department of the Environment (Table 1) and identified on the Miles River tributaries (Leeds Creek: June 14th –18th, Oak Creek: June 26th) and a tidal pond in the watershed near Oak Creek (June 15th). The Miles River empties into Eastern Bay where citizens also reported discolored waters from algal blooms on June 27th. Reports from Horn Point Laboratory researchers also indicated significant patches of algal blooms on the Choptank River on June 26th. Several fish kills were investigated in Leeds Creek, Oak Creek and a tidal pond off the mainstem of the Miles River often associated with low dissolved oxygen (D.O.) conditions and algal blooms or post-bloom conditions. However, cell densities of K. micrum were frequently at concentrations that have been associated with toxin related fish kills in other investigations published by Center for Marine Biotechnology (COMB) researchers and co-authors Dr. Alan Place and Jon Deeds (10,000 to 30,000 cells per milliliter and above). Water samples are being tested by COMB for karlotoxin concentrations, a toxin shown to have fish killing ability (i.e. ichthyotoxicity). Investigations by Maryland Department of the Environment, Horn Point Laboratory and Maryland DNR’s Matapeake Field Office on July 7th located thousands of dead fish over a wide area of the lower Choptank River including many adult menhaden, and a few stripers, croaker and horseshoe crabs. Fish were decaying, drifting over the river and appeared days old suggesting an environmental event that occurred before Monday with an undefined epicenter. Algal samples collected from the Tred Avon River, Trippe Creek and Peachblossom Creek, as well as the Choptank River showed low concentrations of possible harmful algal species Prorocentrum minimum or K. micrum. One live menhaden was found swimming in circles near the surface and was collected for detailed lab analyses.
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Maryland Department of Natural Resources, 580 Taylor Avenue, Annapolis, MD 21401
(877) 620-8DNR