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Fourth Report of the Technical
Advisory Committee
on Harmful Algal Outbreaks in Maryland
15 April 1999
Introduction
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.
References
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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