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A water sample collected from Duvall Creek (South River in Chesapeake Bay) on August 1st contained 220,745 cells/ml of the Raphidophyte, Heterosigma akashiwo. The sample was collected by Drew Koslow, South River Riverkeeper, and the algal species were identified by Maryland Department of Natural Resources staff. A toxicity bioassay was conducted on the sample by the laboratory of Dr. Carm Tomas, University of North Carolina Wilmington, Center for Marine Science. Algal toxin activity was found in the sample but the level of bloom toxicity lacked the ability to kill fish (i.e., no ichthyotoxicity detected). No living resource impacts were observed at the bloom site. Heterosigma akashiwo was also present in bloom densities (6,095-18,000 cells/ml) in Marylands Coastal Bays during mid-June (see HAB News from June 23, 2005: "Heterosigma akashiwo bloom detected in Ayer's Creek, Coastal Bays." and July 26, 2005: Raphidophyte (golden brown algae) blooms detected in Marylands Coastal Bays.). No fish kills or toxic activity were associated with the Coastal Bays bloom locations. There are no documented effects to humans from such H. akashiwo blooms. No fish or human health effects have been associated with blooms of this species in Maryland waters to date. However, toxic activity has been identified from Heterosigma bloom samples and therefore particular attention is given to tracking blooms of the species in connection with the health of living resources in such bloom regions. Maryland DNR conducts a long-term water quality monitoring program that will continue to monitor for algal bloom conditions in the Chesapeake and Coastal Bays. For up to date information on all of Maryland's harmful algal blooms and water quality monitoring results, please visit Eyes on the Bay at www.eyesonthebay.net |