Maryland's Pfiesteria Monitoring Activities
July 24, 1998 Update
Over the last three weeks, more than 48,300 fish were examined. Less than 1 percent had any sort of anomaly. The sampled fish were from trawls and seines from directed scientific activity and from samples from commercial and recreational fishermen. No Pfiesteria-like symptoms were observed.
An unusually large sample of 27,770 menhaden was collected in a 100-foot beach seine sample in the Wicomico. Only 10 of these fish exhibited any sort of skin anomaly and these may very well have been damage from the net collection. Juvenile menhaden are becoming a common component of the catch in all areas as they begin to move into the creeks and rivers.
Reports of striped bass with anomalies ranging from red spots to sores have been increasing. Regional scientists have recently met to discuss this issue, and DNR is leading an investigation into possible causes. Scientists agree that the anomalies are not Pfiesteria. Check out the separate fact sheet on striped bass.
Rapid Response Teams
The Pfiesteria team responded to the Pocomoke river in the area of Williams Point in late June after a person was reported to have become mildly sick after being on the river. Fish, Pfiesteria and water quality samples were taken at three sites near Williams Point. Trawl, electroshock and cast net samples on June 16, 23 and 24 found no indication of problems. In addition, University of Maryland has started baseline studies on cage effects of white perch held in the Pocomoke. In white perch experiments June 24 through June 29, they found no fish disease problems that could related to Pfiesteria.
Water for Pfiesteria analysis was collected from three sites in the lower Pocomoke River on June 25. Analysis by North Carolina State University found no Pfiesteria-like cells in two of the samples and very low levels of possible Pfiesteria-like cells in the third sample. Densities of the possible Pfiesteria-like cells in the one sample are approximately 1/5 of that necessary to result in lesions in fish. They were no fish health problems observed in association with the water collections. Based on the low densities of cells in the sample and the lack of fish health problems, no further analysis of the organisms in the water samples is planned. DNR continues to monitor for any changes to fish health and water quality in the Pocomoke.
Water and Habitat Quality
Systems affected by Pfiesteria last year:
Expanded Pfiesteria monitoring activities:
Water samples are taken to measure common water quality parameters, such as salinity and dissolved oxygen. Specialized samples are also periodically taken to measure nutrients (such as nitrogen and phosphorus) and the amount and type of algae in the water.
Additional Pocomoke River monitoring
Zooplankton (very small animals that feed on algae) will also be collected from a targeted location on the river. Information on zooplankton community composition will be used to provide background information about these populations, and to supplement the information we are gathering on the algal populations in Shelltown area.
Habitat Quality Update
Nutrient and algal comparisons are not possible for the St. Martin and Trappe Creek because long-term historic data does not exist for coastal bay tributaries.
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