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Third Report of the Technical
Advisory Committee
on Harmful Algal Outbreaks in Maryland
March 17, 1998
INTRODUCTION
This is the third report of the Technical Advisory Committee (TAC)
established in July, 1997, by Natural Resources Secretary John R.
Griffin to advise the state agencies on their efforts to monitor the
occurrence and evaluate the causes of fish lesions and fish kills
initially observed in the Pocomoke River. The members of the TAC are
listed in Appendix 1. An Interim Report was submitted on August 14,
1997, and a Second Report on September 12, 1997. These reports were
attributed to the "Technical Advisory Committee on Pocomoke River Fish
Health". By September, 1997, evidence had accumulated to the point that
the Committee concluded that the toxic dinoflagellate Pfiesteria
piscicida or related organisms were the most probable cause of the
fish kills and lesions and these maladies were also observed in two
other tidal tributaries of Maryland's Eastern Shore. Additional
evidence, reviewed below, provides further support to this conclusion.
Reflecting these developments, the Committee herein is referred to as
the "Technical Advisory Committee on Harmful Algal Outbreaks in
Maryland", similar to the terminology used in Secretary Griffin's
original letter of appointment.
In both the Interim and Second Reports the TAC structured its assessment
around seven basic questions related to the incidence, trends, and
location of fish kills and lesions; their probable causes, including
whether Pfiesteria was a factor; and the environmental conditions
and human activities which may underlie these problems. In general, the
TAC took a very cautious position, concluding that: (1) Pfiesteria
or Pfiesteria-like organisms were the most probable, but not
certain, cause of observed fish kills and the lesions on the fish
involved in those kills; (2) multiple other factors could be involved in
causing the high incidence of lesions observed in 1997; and (3) the
introduction of nutrients was the most likely suspect among the human
activities which could have stimulated toxic Pfiesteria events,
but this could not be concluded with great certainty. The TAC counseled
that "our minds should remain open to other explanations of
environmental and biological causes."
A "Technical Workshop on Pfiesteria" was convened on February
18-19, 1998, in Linthicum, Maryland, by the interagency Maryland
Pfiesteria Study Team for the purpose of exchanging information
among interested parties and presenting its plans for the coming warm
season to the Technical Advisory Committee. During this workshop the TAC
revisited the interpretation of the 1997 results for Maryland, received
updates from leading Pfiesteria researchers, and evaluated the
1998 Work Plans to monitor and gain a better understanding of the causes
of toxic Pfiesteria outbreaks in Maryland. After the day and a
half workshop, the TAC met to develop its conclusions and offer
recommendations that would strengthen the 1998 Work Plans.
ASSESSMENT UPDATE
Since the TAC's Second Report in September, 1997, public concern about
the potential risks to human health of Pfiesteria
outbreaks-bolstered by clear evidence that the cognitive abilities of
some human subjects exposed to the affected waters last summer had been
impaired -prompted action to develop policies and programs to reduce
these risks. Governor Glendening appointed the Blue Ribbon Citizens
Pfiesteria Action Commission (Hughes, 1997). At the Commission's
request, a panel of scientific experts on nutrient effects and
dinoflagellate biology prepared a statement expressing the current
understanding on whether outbreaks of Pfiesteria may be reduced
by controlling pollution sources. The resulting "Cambridge Consensus"
(University of Maryland Center for Environmental Science, 1997) produced
a number of findings ending with the following statement: "In the long
term, decreases in nutrient loading will reduce eutrophication, thereby
improving water quality, and in this context will likely lower the risk
of toxic outbreaks of Pfiesteria-like dinoflagellates and harmful
algal blooms." In essence, this group of experts, after reviewing the
literature and field data collected in 1997, was less equivocal than the
TAC's Second Report concerning the relationship of nutrient enrichment
and Pfiesteria. A similar conclusion was reached by an expert
peer-review panel convened by the State of North Carolina (Water
Resources Research Institute, 1998).
Based on the presentations and discussions at the February Workshop the
uncertainties concerning two other issues have also narrowed.
First, there had been limited information and some confusion on the
identity of the dinoflagellates responsible for the toxic conditions.
Pfiesteria piscicida had been confirmed by taxonomic analysis using
scanning electron microscopy only from the Chicamacomico River and not
the other fish kill sites. Subsequently, its presence has been confirmed
at all kill sites (two sites in the Pocomoke River and one site in Kings
Creek). Burkholder and colleagues (1998) presented evidence to suggests
that the failure to confirm P. piscicida in other samples, including
those from which toxin-producing forms were cultured, was due to culture
methods. They also summarized results that demonstrated indications of
the presence of P. piscicida in samples from each of the Pocomoke River
fish kill locations. Finally, they presented methodologies for
distinguishing Pfiesteria and another Pfiesteria-like
dinoflagellate from other species with which they might be confused.
Secondly, there have remained questions about whether Pfiesteria
is responsible for the lesions or whether they were caused by other
factors, particularly infective diseases. Because the lesions on freshly
killed fish were extensively invaded by bacteria and fungi, it has been
suggested that these lesions were originated by other agents before the
exposure of the fish to Pfiesteria-toxins. While this may be the
case, it is well known that under experimental conditions Pfiesteria-toxins
can produce similar lesions and it is quite possible that these lesions
were initiated by earlier, sublethal exposure to Pfiesteria
toxins.
THE 1998 WORK PLANS
The 1998 Work Plans were broken into four distinct areas: (1)
Pfiesteria-Related Fish Health Investigations, (2) Fish Health,
Habitat Quality and Pfiesteria Surveillance, (3) Pocomoke Event
Sampling for Toxic Substances, and (4) Watershed Pollution Source
Assessment. TAC comments and recommendations on each follow below:
1. Pfiesteria-Related Fish Health Investigations
It was generally felt that the fish health investigations described in
this section are not necessarily directed to understanding the onset of
lesions caused by Pfiesteria, but are developed to get an
indication of fish health throughout the Chesapeake region. While these
studies may be necessary for a multitude of reasons, the TAC only
focused on the Pfiesteria-related investigations.
Experimental studies. The TAC had problems evaluating the experimental
studies because no hypotheses were explicitly stated to justify the
experimental design and extensive laboratory analyzes. It seemed that
the experiments were still being conceived as a determination of whether
Pfiesteria causes lesions, when this is well known from
laboratory experiments and field observations in North Carolina. Rather,
these experimental studies could prove very useful in determining
whether an elevated incidence of lesions provides, as assumed in the
current operational protocol, an effective warning for toxic
Pfiesteria outbreaks. Experiments should be designed to test
specific hypotheses regarding the degree to which lesions constitute an
adequate indicator of toxic Pfiesteria conditions. While the TAC
recognizes the difficulty in conducting in situ menhaden experiments,
the lack of attention to the species, which appears to stimulate toxic
Pfiesteria outbreaks and be most affected by them, calls into
question the purpose of the experiments altogether. Experiments should
concentrate ideally on menhaden, but alternately on white perch as a
surrogate, and should be conducted in areas that have had toxic
Pfiesteria outbreaks or areas where fish with lesions are found.
Laboratory analyzes of fish health parameters. Some members of the TAC
wanted more details regarding the laboratory analyzes, particularly the
stress response evaluations. Caging and handling effects on stress
indicators should be thoroughly tested before any broader application of
these methods.
2. Fish Health, Habitat Quality and Pfiesteria Surveillance
The Work Plan for this broad topic includes a diverse array of field
observations on water quality, fish, and Pfiesteria that are
based on a four-tier sampling strategy accommodating rapid response
(Level I) and comprehensive assessments within previously closed
tributaries (Level II), other tributaries potentially at risk (Level
III), and in other areas covered by on-going monitoring programs (Level
IV). This framework is a reasonable approach that provides focus and
sets priorities while at the same time allows flexibility. However,
coordination between the fish health and habitat quality components
should be strengthened.
Fish community monitoring. The TAC recommends that fish community
monitoring at least at some Level IV stations include sampling gear that
can specifically sample menhaden from May through October. The TAC
recognizes that much of the Level IV sampling is occurring for other
specific reasons but that incorporating menhaden would add value to the
ongoing efforts. The TAC also encourages the DNR to coordinate menhaden
and other fish sampling efforts with other states in the mid-Atlantic
region.
Habitat quality monitoring. The TAC is concerned that all Level III
river systems are along the lower Eastern Shore and do not include
tributaries in the upper Eastern or Western Shores of the Chesapeake
Bay. Pfiesteria is known to occur in some of these areas (e.g.
Choptank and Patuxent rivers). The TAC understands that additional Level
III river systems may be chosen depending on funding availability and
recommends that any additional Level III systems be chosen considering
the following conditions: areas with relatively fine sediments, shallow
bathymetry, weak currents, and high nutrient levels and where fish tend
to congregate.
The TAC highly recommends that some species of dissolved organic
nitrogen (DON), particularly urea, be directly measured in light of
preliminary research that suggests a relationship with harmful algal
species. Total DON cannot be directly measured, without measuring all of
its constituents, therefore the difference method of calculating DON (TN
- DIN = DON) should be continued at all Level I - III stations.
The TAC recommends that algal community sampling and analysis be done
for some stations throughout the sampling season. Relatively rapid
techniques such as in situ flourometry (for chlorophyl a
concentrations), high-powered liquid chromotography (to identify and
quantify pigment groups), and epiflourescent microscopy (for general
identification) should be applied on a regular basis for all Level I -
III stations. Direct counts could be completed on a subset of samples.
Alan Lewitus, a TAC member, is willing to provide further details
regarding specific methodology.
The TAC recommends that samples to determine the presence and abundance
of Pfiesteria-like dinoflagellates should be taken and analyzed
in all Level I -III river systems. This would include these Level III
systems where fish kills potentially related to Pfiesteria have
not yet been observed. Furthermore, the TAC feels that Maryland and its
neighboring states should develop identification capabilities within the
Chesapeake Bay region.
In addition to the sampling described in the Work Plan, the TAC
recommends that some latitudinal sampling (i.e. shore to shore) take
place around some stations and sediment DOM (pore water) measurements be
taken at selected stations, if funds and staff time are available.
3. Pocomoke Event Sampling for Toxic Substances
The TAC concurs with the Work Plan that the spring sampling needs to be
completed. However, further sampling may only warranted after the data
are analyzed from an ecorisk perspective, including a literature search
of the effects of the toxicants on a variety of species (from algae to
fish) with a consideration of sub-lethal effects. If this analysis does
not find any reason for concern then toxic sampling should only be
conducted to address specific hypothesis-driven questions. The TAC is
concerned about the continued support of the many partners enlisted to
complete the toxic analysis and hopes that the partnerships will stay
intact to complete the spring analysis.
4. Watershed Pollution Source Assessment
While the TAC does not have the expertise to review this section
adequately, it appeared to some members as fragmentary and not well
coupled with the event sampling and comprehensive assessments of tidal
waters. Therefore, the Chair has offered to convene a group of state,
federal and academic scientific experts to consider methods to conduct
watershed assessments in a much larger context, including better
integration of existing efforts and refinement of models that relate the
results of small watershed modeling to estuarine loadings. The
Departments of Environment, Natural Resources, and Agriculture and the
U.S. Geological Survey, as well as several academic experts, have agreed
to participate. This forum should take place during March or April,
1998. If scheduling conflicts occur, the TAC will seek advice regarding
this section from a smaller group of experts who will solely consider
this section of the Work Plan.
5. Coordination
In its review of the 1997 Work Plan, the TAC, while recognizing the
necessary haste in its preparation, criticized the lack of coordination
among the components of the monitoring and assessment plan.
Specifically, we noted the need for a more clearly stated strategy with
specific questions or hypotheses, priorities and sequences. We also
recommended the requirement for a larger regional framework beyond the
Pocomoke River and a strong leadership and management structure. The TAC
is pleased to observe considerable improvements in the 1998 Work Plans,
including the development of the four-level assessment strategy that
provides both a framework for coordination of sampling but also for
broader regional assessment. We are also pleased to learn that the 1998
Work Plans were produced through the active efforts of the interagency
Maryland Pfiesteria Study Team. However, we also note that in
complex and challenging efforts such as this there is always room for
significant improvement in coordinated design, execution, and
interpretation.
OTHER ISSUES
As the objectives and focus of Maryland's monitoring and assessment have
evolved based on information collected and questions answered, the TAC
finds itself with inadequate expertise in several important technical
fields. The TAC was formed principally of individuals with expertise in
fish health and algal ecology. As assessments have focused increasingly
on nonpoint source inputs of nutrients and the effects of those
nutrients in the estuarine ecosystem, new members should be added to the
TAC to bolster its expertise in those areas. In addition, TAC expertise
is needed in fish population ecology to assist in assessment of the
consequences of the effects of diminished fish health and Pfiesteria-related
mortalities on the resource stocks.
A number of large research proposals have been submitted to federal
sponsors by Maryland investigators related to Pfiesteria. These
include multi-investigator proposals to the interagency Ecology and
Oceanography of Harmful Algal Bloom (ECOHAB) program to identify toxins
and their effects and understand the connections between nutrient
enrichment and Pfiesteria-like dinoflagellates and a proposal to
the National Institute for Environmental Health for a major center to
study human health-related effects. Assuming at least partial success of
these research proposals, Maryland should be presented with unusual
opportunities afforded by the coincidence of extensive monitoring and
research activities. Effective coordination and integration of these
efforts will allow experimental testing of hypotheses formulated from
the observations and, conversely, will provide an extensive background
context seldom afforded for research. Such effective coordination is not
only an opportunity but an obligation. The TAC urges the state agency
managers and university researchers and administrators to work closely
toward this end.
REFERENCES
Brukholder, J.M., H.B. Glasgow, and E.K. Hannon. 1998. The Toxic
Pfiesteria Complex vs. Mistaken Identities in the Albemarle-Pamlico
and the Chesapeake. Summary Position Paper, February 1998.
Jordan, S.J., and E.B. May. 1998. Histological and Microbiological
Findings Studied on Fish Taken from the Pocomoke River and Adjacent
Tributaries. Maryland Department of Natural Resources, Oxford, Maryland.
Hedrick, J.D., and F.J. Margraf. 1998. Distribution, Progression, and
Species Specific Incidence of Fish Skin Abnormalities in the Pocomoke
River System. Maryland Cooperative Fish and Wildlife Research Unit,
University of Maryland Eastern Shore, 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 the Environment. 1998a. Pocomoke Watershed
Pollution Assessment: Background and Summary of Results to Date.
Baltimore, Maryland.
Maryland Department of the Environment. 1998b. Summary of Results of
Monitoring for Chemical Contamination in the Lower Pocomoke River.
Baltimore, Maryland.
Maryland Department of Natural Resources. 1998a. Histological
Investigations--Pfiesteria--1996/1997. Oxford, Maryland.
Maryland Department of Natural Resources. 1998b. Water Quality and
Pfiesteria Studies of 1997. Annapolis, Maryland.
Maryland Departments of Natural Resources, Environment, and
Agriculture. 1998. 1998 Work Plans.
Technical Advisory Committee. 1997a. Interim Report of the Technical
Advisory Committee on Pocomoke River Fish Health. Maryland Department of
Natural Resources, Annapolis.
Technical Advisory Committee. 1997b. Second Report of the Technical
Advisory Committee on Pocomoke River Fish Health. Maryland Department of
Natural Resources, Annapolis.
Water Resources Research Institute of The University of North
Carolina. 1998. The Raleigh Report 1998: Pfiesteria Research
Needs and Management Actions. Report No. SRS-19. Raleigh, NC.
University of Maryland Center for Environmental Science. 1997. The
Cambridge Consensus: Forum on Land-Based Pollution and Toxic
Dinoflagellates in Chesapeake Bay. Cambridge, Maryland.
Appendix 1
Technical Advisory Committee on Harmful Algal Outbreaks in Maryland
Dr. Donald F. Boesch*, Chair University of Maryland Center for
Environmental Science
Dr. Robert Anderson* (immunology) Chesapeake Biological Laboratory
University of Maryland Center for Environmental Science
Dr. JoAnn Burkholder* (algal ecology) North Carolina State University
Dr. Eugene Burreson (diseases of marine organisms)
Dr. Larry Haas, alternate* (phytoplankton ecology, water quality)
Virginia Institute of Marine Science
Dr. Mary Haasch* (fish toxicology) Chesapeake Biological Laboratory
University of Maryland Center for Environmental Science
Dr. Sherwood Hall* (monitoring harmful algal blooms) U.S. Food and
Drug Administration
Dr. Reginal Harrell (fish culture and physiology) Horn Point
Laboratory University of Maryland Center for Environmental Science
Dr. Michael Hirshfield* (environmental conservation) Chesapeake Bay
Foundation
Dr. Andrew Kane* (aquatic pathology and toxicology) Aquatic
Pathobiology Center University of Maryland School of Medicine
Mr. Richard Lacouture* (phytoplankton monitoring) Environmental
Research Center Academy of Natural Sciences
Dr. Alan Lewitus* (algal culture and ecology) Belle Baruch Institute
University of South Carolina
Dr. Harold Marshall* (phytoplankton monitoring) Old Dominion
University
Dr. Kevin Sellner* (algal bloom ecology) Coastal Ocean Program
National Oceanic and Atmospheric Administration
Dr. Karen Steidinger (ecology and management of harmful algal blooms)
Marine Research Institute Florida Department of Environmental Protection
Dr. Diane Stoecker* (heterotrophic microplankton) Horn Point
Laboratory University of Maryland Center for Environmental Science
Dr. Daniel Terlizzi (aquaculture) Maryland Cooperative Extension
Service University of Maryland, College Park
Dr. Patricia Tester (dynamics of algal blooms) Beaufort Laboratory
National Oceanic and Atmospheric Administration
*Attended the February 18-19, 1998 workshop. |