The following summarizes on-going investigations during the past several weeks into harmful algal blooms (Chattonella). To date, there is no evidence of active toxicity from either of these organisms.

Marshall Creek (Coastal Bays): Routine monitoring on September 25 revealed high densities of Chattonella cf. verruculosa in Marshall Creek. This is a potentially toxic species which can result in fish kills and potentially harm humans at high toxin levels. The species does not always produce toxin and, if it does, must typically be present at densities above 10,000 cells / ml to begin to see impacts on fish health. Follow-up monitoring on October 2 revealed approximately 2,500 cells / ml. Healthy fish were observed at the sampling site. Water was sent to University of North Carolina at Wilmington for toxin analysis. Results are pending. Maryland DNR will next sample Marshall Creek on Tuesday, October 8.