July 6 , 2004
Heterosigma akashiwo bloom detected in Upper Newport Bay.

A potentially ichthyotoxic (i.e., toxic to fish) algal species, Heterosigma akashiwo was identified by Maryland Department of Natural Resources during routine water quality monitoring on June 30 in upper Newport Bay, Coastal Bays, at bloom densities for the species (38,000 cells per milliliter). The species is best known for its relationship with fish kills around the world, (Asia being one focal area due to effects this alga has generated on net pen aquaculture operations). Fish kills have occurred in regions of the world with abundances starting at roughly > 1,000 cells per milliliter of H. akashiwo. No fish kills were associated with the Coastal Bays location. Toxin testing was conducted on the water sample by Dr. Carm Tomas (University of North Carolina-Wilmington) for brevetoxin, (i.e., a toxin that is a concern to human health and is produced by related species among the group of algae that H. akashiwo belongs to, the Raphidophytes), and was negative. Dr. Tomas additionally conducted a fish bioassay assessing any toxic activity towards fish and this test was also negative.

The MD DNR will continue to monitor this bloom. For up to date information on all of Maryland's harmful algal blooms and water quality, please visit Eyes on the Bay