Maryland's Pfiesteria Response

June 22, 1998 Update


Water Quality and Fish Health:
Surveys of fish health and water quality have been ongoing along 20 rivers and areas of the Chesapeake Bay, including six tributaries of special interest (Pocomoke, Manokin/Kings Creek, Chicamacomico, Nanticoke, Big Annemessex, and Eastern Shore Wicomico) and two coastal bays tributaries (St. Martin and Newport Bay) since February 1998. The health of the sampled fish populations generally appears normal, with less than 1 percent of the more than 90,000 fish collected exhibiting any kind of external abnormality. Not surprisingly, this year's wet and warm winter has resulted in lower salinities and higher water temperatures than typically seen at this time of year on many of the sampled rivers. Data on the nutrient concentrations in these rivers has not yet been received back from the laboratories and fully analyzed. Fish health surveys will continue weekly and water quality surveys will continue monthly on these rivers throughout the summer and fall.

State agencies have responded to two localized fish health problems that generated some concern. First, in mid-May, dead and lesioned catfish were reported in Back River. Fish health problems are not uncommon during the Spring and Summer on this heavily nutrient enriched tributary. Bacterial infection was suspected, but samples for Pfiesteria were collected as a precaution. The Pfiesteria samples were negative, and subsequent investigations confirmed a bacterial species (Flexibactor) as the cause of the problem. Second, intermittent reports of dead white perch have been received from both sides of the Potomac River in the vicinity of the Route 301 bridge since early May. Follow-up investigations have also found a higher than normal percentage of white perch with lesions from this area. The type of lesions observed did not suggest Pfiesteria as the cause, but samples were collected as a precaution. Again, results of the Pfiesteria analysis were negative. Preliminary results of an on-going investigation in collaboration with researchers at University of Maryland suggest a bacterial infection as the cause. More definitive results from this investigation are expected in the very near future.

Rapid Response teams are in place and ready to evaluate fish health problems as they are reported to the Fish Health Hotline (1-888-584-3110). To date, Rapid Response teams have investigated 16 fish health events, all of which were explained by factors other than Pfiesteria. Additionally, a field office has been established in Vienna, and is now operational.

Pocomoke Watershed Pollution Source Assessment: The watershed pollution source assessment is designed to identify all major contributors of pollutants to the Pocomoke River and to evaluate the effectiveness of on-going pollution control efforts. To date, State and federal agencies have worked together to measure base and storm flow water quality at several sites in the watershed, as well as sediment grain size and phosphorus concentrations both in the river mainstem and several tributaries. Samples collected during this effort are currently being analyzed by the laboratories. Information derived as part of this effort will be synthesized with the results of the on-going "paired watershed" study in the upper watershed, which seeks to evaluate the impact of various agricultural practices on water quality.

Chemical Contaminants: Analysis of chemical contaminants in the lower Pocomoke River following last summer's fish kills and lesion events revealed no significant levels of contaminants. More samples were collected twice this spring (May 9,11 and June 13,15) during storm runoff events after the period of peak agricultural pesticide application. It is expected to take a couple months for analysis to be completed on these samples.

Federal Coordination: Representatives of Maryland State agencies are working closely with federal partners (primarily EPA and NOAA) to ensure a coordinated regional response to the threat of Pfiesteria outbreaks. Levels of interaction are many, but include standardization of sampling and data management protocols, coordination of sample analysis and data interpretation with the two primary laboratories (Dr. JoAnn Burkholder at North Carolina State University and Dr. Karen Steidinger at Florida Department of Environmental Protection), and the development of an Internet "listserver" that allows rapid communication of breaking events among key State and federal representatives. In many cases, Maryland's strategy for responding to the threat of Pfiesteria is being used as a model for adoption by other states along the Atlantic coast.

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