Fish kill investigation underway in Massey Branch, Marshall Creek, Coastal Bays
Maryland Department of the Environment (MDE) investigated a fish health event that was observed at 6 AM on August 17th by a landowner along Massey Branch of Marshall Creek, (Worcester County, Coastal Bays). A fish kill of menhaden was found later that morning and water samples collected at the site have shown presence of two algal species that are sometimes toxic, Pfiesteria piscicida and Chattonella verruculosa, confirmed by genetic probe work at Dr. Oldachs laboratory (University of Maryland Biotechnology Institute). Concentrations for Chattonella species that may have included C. verruculosa and the apparently non-toxic C. subsalsa ranging between 11,448 cells/ml to 70,000 cells/ml based on Maryland Department of Natural Resources (DNR) and Academy of Natural Sciences Estuarine Research Center results. Dissolved oxygen levels were below state standard guidelines (i.e., 5 mg O2/L at all times) downstream of the kill site (4.9 mg/L) and above standards upstream (5.9 mg O2/L). The epicenter of the kill area was supersaturated with oxygen at 10.9 mg O2/L. All measurements were recorded during late morning hours. On Tuesday (August 20th) and Wednesday (August 21st) the site was revisited and concentrations to 9,045 cells/milliliter of the apparently non-toxic alga Chattonella subsalsa were found in Marshall Creek and nearby Newport Creek by DNR. No additional fish kills have been observed in Marshall Creek and DNR is continuing to monitor water quality in the region.