Fourth Report of the Technical Advisory Committee
on Harmful Algal Outbreaks in Maryland

15 April 1999


This is the fourth report of the Technical Advisory Committee (TAC) initially established in 1997 by the Secretary of Natural Resources, John R. Griffin, to advise the state agencies on their efforts to monitor the occurrence and evaluate the causes of fish lesions and kills in the Pocomoke River. In September 1997, the TAC concluded in its Second Report that toxic Pfiesteria piscicida or related organisms (herein simply referred to as Pfiesteria) were the primary cause of lesions and fish kills in the Pocomoke River. Similar events occurred, that same year, in both Kings Creek and Chicamicomico River. In the fall of 1997, the State developed a comprehensive monitoring plan to detect and diagnose potential outbreaks of toxic Pfiesteria in order to reduce the risk to human health and assess causative environmental conditions of several lower Eastern Shore rivers. That plan was reviewed by the TAC and was largely the subject of its Third Report. The State began to implement the plan in the Spring of 1998.

The "Second Annual Technical Workshop on Pfiesteria" was convened on 23-24 February 1999 in Linthicum, Maryland by the Lower Shore Pfiesteria Study Team for an exchange of information between interested parties. Several presentations were made by leading scientists in the environmental, biotechnology, and medical fields whose research is related to Pfiesteria. In addition, the Study Team presented its 1998 findings as well as its monitoring plans for 1999. After the day and a half workshop, the TAC met with the Study Team to discuss the 1999 monitoring plans and develop preliminary recommendations.

Assessment Update

In 1998, Maryland’s Rapid Response Team sampled three areas of the Potomac River, Chicamacomico River, and Shiles Creek, for potential toxic Pfiesteria blooms. Of these three systems Pfiesteria was found in very low concentrations in the Chicamacomico River and Shiles Creek with no apparent fish kills. Maryland experienced no river closures throughout 1998. Sediment samples were also collected at 50 sites in 12 tidal rivers in order to determine whether cysts may exist that could develop into toxic stages of Pfiesteria. Of the 30 samples incubated in the laboratory (as of 23 February 1999) in the presence of fish for longer periods than is usual in toxic bioassays, those from four rivers yielded toxin-producing effects: the Chicamacomico, Big Annemessex, and Pocomoke rivers of the Chesapeake Bay and St. Martin River of the coastal bay system. This does not mean that toxic Pfiesteria were actually found at these sites, but that organisms were present in the sediments that could, under the right conditions, metamorphose into toxin-producing life stages.

The development and use of new technologies to rapidly identify Pfiesteria and Pfiesteria toxins are progressing extremely well. Field testing of several of these technologies began in1998 and more is expected in 1999. One of the difficulties that continues to challenge the scientific community is the discovery of several new Pfiesteria-like species. The taxonomy of these new species have not been fully defined, it is not yet known if they produce the same toxins, require different genetic markers, or how their ecological requirements differ from Pfiesteria piscicida.

Many new Pfiesteria-related research programs began in Maryland during 1998 as a result of several different federal and state funding initiatives. Maryland researchers have been successful in receiving three different nationally competitive grants from the Federal interagency ECOHAB Program (Ecology and Oceanography of Harmful Algal Blooms). One grant supports a multi-state study, led by the University of Maryland Center for Environmental Science (UMCES) researchers, of the environmental conditions (nutrient composition and concentrations, nutritional ecology, and physical conditions) which lead to Pfiesteria growth and toxic outbreaks. The other two grants have been awarded to researchers at the University of Maryland School of Medicine and the University of Maryland Biotechnology Institute (UMBI) to develop genetic probes for rapid identification of Pfiesteria. The University of Maryland School of Medicine in conjunction with the Maryland Department of Health and Mental Hygiene received funding from the Centers for Disease Control to conduct a cohort study to determine and monitor the effects of "estuarine associated syndrome" in humans. The University of Maryland School of Medicine, Johns Hopkins University and UMBI also received funding from the National Institute of Environmental Health Sciences to conduct research on toxin production Pfiesteria and on the mechanisms by which these toxins affect human health. The State of Maryland through the Department of the Environment provided $800,000 in matching grants for equipment and facilities for these projects. In all, over $5 million has been provided by state and federal governments for research on Pfiesteria and the causes and consequences of toxic blooms, with the multi-year awards over the next five years totaling nearly $15 million.

Since its Third Report, the TAC convened two separate special meetings to address specific concerns on (1) the 1998 Watershed Monitoring Work Plan, and (2) the causes and consequences of menhaden lesions. The TAC felt that it did not have the expertise in its membership to properly review the Watershed Monitoring Work Plan. Therefore, on 22 April 1998 a meeting was convened between members of the Lower Shore Pfiesteria Study and regional experts in the fields of hydrology and landscape ecology. The meeting recommendations were summarized in a report submitted to the Department of Natural Resources entitled “Eastern Shore Studies Workshop.” The Lower Shore Pfiesteria Study Team considered these recommendations and strengthened their monitoring efforts considerably.

Throughout 1998 several press reports came out regarding the fact that fish pathologists had consistently found a fungal infection in menhaden with lesions. This raised questions regarding the connection among Pfiesteria, fungus, and lesions. In the laboratory, previous research has shown that Pfiesteria toxins can erode the skin of fish. The TAC sponsored a dedicated meeting on 16 December 1998 to bring together fish pathologists, fisheries scientists, other researchers who have studied the relationship between fish and Pfiesteria, and members of the Lower Shore Pfiesteria Study Team. The participants wrote a consensus report “Causes and Significance of Menhaden Lesions” which included three major findings:

1) Fungal infections were not found on the smallest lesions and few fish collected from kills in which Pfiesteria was implicated have been examined for fungal infections. Consequently, Pfiesteria toxins cannot be ruled in or out as initiators of fresh lesions or deep ulcers.

2) The development of lesions is not required for Pfiesteria toxins to kill fish, consequently the uncertainty surrounding the causes of lesions does not call into question the linkages among fish kills, human health risks, and toxic Pfiesteria outbreaks.

3) This uncertainty does, however, mean that the prevalence of fish lesions alone should not be considered a reliable indicator of toxic Pfiesteria outbreaks.

Although much still remains to be understood, the accumulation of more refined information from the 1997 events, observations during the more modest 1998 phenomena, and recent results from North Carolina add to the weight of evidence that outbreaks of toxic Pfiesteria piscicida—and perhaps other related species—were involved in the fish kills and pathologies and the human health maladies that occurred in 1997. More research and monitoring is clearly required to resolve the environmental conditions which favor these Pfiesteria outbreaks, with nutrient over-enrichment still a likely suspect. Perhaps the most encouraging development over the past year has been the progress in resolving the genetic identity of Pfiesteria piscicida and related forms. These discoveries will ultimately lead to technologies capable of providing real-time, and maybe even advance, warning of health risks.

The 1999 Work Plans

The 1999 Work Plans were broken into three main topics: 1) Fish Health; 2) Water and Habitat Quality and Pfiesteria Surveillance; and 3) Watershed and Pollutant Assessments. The TAC was pleased with the 1998 monitoring program and commends the hard work of the Lower Shore Pfiesteria Study Team. Specific comments and recommendations are below to make the 1999 monitoring program even stronger.

1. Pfiesteria-Related Fish Health Investigations

Analysis of Fish with Lesions. The TAC strongly recommends that fish be collected during a presumed toxic Pfiesteria outbreak. Fish samples and/or slides should be sent to several different labs for analysis and comparisons of the pathology and microbiological fauna. If possible, blood should be archived for detection of Pfiesteria toxins if and when new technological tools can be applied.

Cage Experiments. These experiments were instrumental in determining that the fishing gear, fyke nets, did not appear to be the cause fish lesions in white perch. The TAC believes that adequate baseline data have been collected on white perch and that future experiments, if feasible and conducted, should use menhaden. However, there are substantial caging effects, including fin erosion and initiation of lesions that will, even in the best case, limit the usefulness of caging experiments to very short-term deployments to determine acute toxicity.

Distribution and Abundance of Menhaden. No recent menhaden distribution and abundance studies have been conducted in Maryland's portion of the Chesapeake Bay. Since menhaden are the primary fish species affected by toxic Pfiesteria blooms, it may be useful in determining areas that may be more susceptible than others. The TAC recommends the use of fishery independent methods to determine and possibly track menhaden distribution and abundance in Maryland waters (summer and fall) with tools such as underwater acoustic samplers or aerial spotters.

2. Water and Habitat Quality

Microplankton Composition. The TAC recommends that water samples be analyzed under an epiflourescent microscope to distinguish the heterotrophic and autotrophic components of the microplankton. While costly both in time and money, this technique would provide data useful for exploring relationships between components of the microplankton, including plankton succession and associations of Pfiesteria and its prey. Additionally, the TAC recommends that samples be archived so that identification of species (or the lowest taxonomic level possible) at a later date can be completed if it is deemed necessary and funding was available.

Algal Biomass Sampling. In vivo flourescence, as an indicator of algal biomass, is presently being measured monthly in Level II and III rivers (twice monthly in the Pocomoke and Chicamacomico Rivers). The TAC recommends that sample frequency be increased to every other week in Level II and III systems and conducted weekly in the Pocomoke and Chicamacomico Rivers. Additionally, these samples should be compared to algal pigment analysis (through the use of high performance liquid chromatography) for the lower Eastern Shore Rivers being sampled through Dr. Glibert's ECOHAB research program.

Presumptive Pfiesteria Counts. While the TAC recognizes the importance and utility of the various DNA probes being developed, it is still very important for continual presumptive Pfiesteria counts to be made. At this time, probes appear to be able to determine if Pfiesteria is present, but cannot yet estimate abundance or more importantly presence of the toxic stages. Presumptive counts give a relatively quick assessment whether Pfiesteria is present or its magnitude. Additionally, the TAC is encouraged that the reporter gene assay for detection of the presence of components was effective in field tests in North Carolina in 1998 and supports its application in potential Chesapeake Bay toxic outbreaks during 1999.

3. Watershed and Pollutant Assessments

Contaminant Assessment. In the fall of 1997, USGS scientists collected water and sediment samples to analyze for metal concentrations. They reported unusually high concentrations of arsenic, selenium, strontium, and lithium in some water samples from the Pocomoke River. Before these results were received by the State, sampling was conducted by scientists from UMCES during spring 1998. Several differences between the sampling methods, analysis, and metals tested have made these two data sets difficult to compare. In early February 1999, both groups from USGS and UMCES sampled together and they will analyze the samples separately to conduct an inter-lab comparison. In addition samples will be sent to a private laboratory for a third analysis. When these comparisons are completed it will be important for the results to be presented in a watershed and geochemical context and interpreted from a risk-assessment perspective. For example, other USGS scientists reported high concentrations of suspended iron oxide precipitates when anoxic and dissolved iron-rich groundwater reaches surface ditches during low-flow periods in the Pocomoke; these precipitates could provide a mechanism for scavenging certain metals, thus elevating their apparent concentrations in a water sample. Following the analysis, the TAC plans to convene a dedicated workshop on metals and other contaminants (herbicides and pesticides) in relation to Pfiesteria outbreaks. It is expected that this workshop will refine future monitoring of metals and other contaminants (for example, the spatial coverage of stations) and key research questions (for example, related to fluxes from sediment, interactions with fungicides, bioavailability, and effects on trophic interactions).

Watershed Loading Assessment. A model will be used to assess nutrient loads entering the Pocomoke from the suite of sources (point, non point, and atmospheric) and consider land use and implementation of management practices. The model will be derived from the Chesapeake Bay Program model and Maryland's Total Maximum Daily Load Program. The TAC recommends the that the model used for the Pocomoke consider: extensive ditching in the area, groundwater lag time, and the lag time associated with newly installed best management practices.

Emerging Issues

Research and monitoring concerning Pfiesteria has greatly expanded, powerful new methods are rapidly being developed, and knowledge is building. The TAC recommends that Maryland’s monitoring and assessment program keeps an eye on this changing environment and, to the degree possible, anticipates developments ahead. In particular, we suggest the following be considered:

1) to the maximum extent possible, samples which could yield Pfiesteria or its toxins should be archived pending the development of techniques that allow detection and quantification;

2) every opportunity should be taken to coordinate monitoring and research programs to take advantage of this rare opportunity to link observational and experimental science contemporaneously;

3) assist research related to the detection and quantification of toxins or toxin-producing life forms.


Hedrick, J.D., L.B. Ras, F.J. Margraf, J.M. Jacobs, R.M. Harrell, B. Coakley, B. Kibler, C. Driscoll, S. J. Jordan, A. Baya, and J. Evans. 1999. Fish Health Aspects of Pfiesteria Investigations in Maryland. Princess Anne, Maryland.

Hughes, H.R. (Chair). 1997. Blue Ribbon Citizens Pfiesteria Action Commission, Final Report. Office of the Governor, Annapolis, Maryland.

Maryland Department of Natural Resources. 1999a. Comprehensive Fish Health (Lesion) Sampling - 1998. Annapolis, Maryland.

Maryland Department of Natural Resources. 1999b. Assessment of Water Quality, Habitat and Biological Conditions to Fish Health and Pfiesteria-like Organisms in Maryland. Summary 1998. Annapolis, Maryland.

Maryland Department of Natural Resources. 1999c. Water Quality, Habitat, Pfiesteria and Associated Biological Communities: 1999 Workplan. Annapolis, Maryland.

Maryland Departments of Environment, Natural Resources, and Agriculture, United States Geological Survey, Natural Resources Conservation Service, and the Wicomico, Worcester and Somerset Soil Conservation Districts. 1999a. Watershed Pollution Source Assessment 1998 Progress Report. Baltimore, Maryland.

Maryland Departments of Environment, Natural Resources, and Agriculture, United States Geological Survey, Natural Resources Conservation Service, and the Wicomico, Worcester and Somerset Soil Conservation Districts. 1999b. Watershed Pollution Source Assessment Workplan 1999. Baltimore, Maryland.

Technical Advisory Committee. 1998a. Third Report of the Technical Advisory Committee on Harmful Algal Outbreaks in Maryland. Maryland Department of Natural Resources, Annapolis.

Technical Advisory Committee. 1998b. Eastern Shore Studies Workshop. Maryland Department of Natural Resources, Annapolis.

Technical Advisory Committee. 1999. Causes and Significance of Menhaden Lesions. Maryland Department of Natural Resources, Annapolis.

University of Maryland Center for Environmental Science. 1997. The Cambridge Consensus: Forum on Land-Based Pollution and Toxic Dinoflagellates in Chesapeake Bay. Cambridge, Maryland.

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