&EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 2O460
EPA/600/SR-98/147
December 1999
www.epa.gov
MAIA Project Summary
Condition of the Mid-Atlantic
Estuaries
The Condition of the Mid-Atlantic Estuaries Report, publication no. EPA 600-R-98-147, was published in November
1998 and received wide distribution. This Project Summary is an overview of the important points presented in that
report. To obtain the full report, call the MAIA Team at 410-305-2749. An electronic version of the report is available
through the World Wide Web at http://www.epa.gov/emap/html/cond_mae.htm.
The Mid-Atlantic Integrated Assessment
(MAIA) is an interagency, multi disciplinary research,
monitoring and assessment program to develop high-
quality scientific information on the region's natural
resources: current condition, stressors, trends, and
vulnerabilities. MAIA results and information must
satisfy a broad group of stakeholders' needs, convey
important information relevant to their assessment
questions and issues, and be understandable and useful
in making management decisions.
OVERVIEW
Estuaries are transitional zones where salt water from
the sea mixes with fresh water flowing off the land
(Figure 1). They provide habitat for many birds,
mammals, fish and other aquatic life. Therefore^
estuaries are important assets that humans use in a
wide variety of ways. The report focuses on the
^current condition of the Mid-Atlantic estuaries from the
jptly~ to mid-1990s, and how and why the estuaries
have changed over the years. The Mid-Atlantic
Sis OFF/ Chesapeake Bay
estuaries included in the report are: the Delaware
Estuary, Chesapeake Bay and Delmarva coastal bays.
Figure 1. Schematic diagram
of physical, chemical, and
biological processes interacting
in estuaries.
Fresh-saltwater transition
(maximum turbidity zone)
Point sources
sewage treatment
plants (N+T)
fr, Nonpoint sources
farm & urban runoff,
groundwater(S+N+T)
•;.^<«3«^.
Source: Redrawn from USEPA, 1987
Sediment (S)
Nutrients(N)
Toxic pollutants (T)
See the full report for all
reference sources.
Sedimentabsorption
& transport
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Condition of the Mid-Atlantic Estuaries was
prepared by scientists from EPA's Office of Research
and Development, Narragansett, Rhode Island, in
collaboration with individuals from EPA Regions II and
III and numerous other EPA offices; the states of
Maryland, Virginia, and Delaware; the National
Oceanic and Atmospheric Administration; the U.S.
Geological Survey; and the U.S. Fish and Wildlife
Service. It represents the synthesis of information
published in a variety of independent scientific
publications or contained in established scientific
databases. Numerous research studies have been
prepared by Federal and state programs and by
academic researchers for individual states or
estuaries; however, a comprehensive report including
water quality, sediment contamination, habitat change,
and the condition of living resources had never been
done on a regional scale. Data from across Federal and
state programs have been used and comparisons across
systems within the Region have been made. The report
not only identifies specific geographic problem areas, but
estimates the percentage of estuarine area that is in
good condition, is in moderate condition, or is degraded
based on various estuarine indicators.
ENVIRONMENTAL
The Mid-Atlantic Region has experienced some of the
most rapid population growth, industrial growth, and
intensive agriculture in the country. From 1950 to
1990, the population has grown from 13 to 21 million.
By 2020 an estimated 25 million people will be living in
the estuarine watershed of the Mid-Atlantic Region.
(Figure 2). This growing population will require land
for homes, transportation, shops, jobs, and recreation.
Urban land currently comprises 5% of the region's
watershed and generally is close to the estuarine
shoreline. As watersheds become more developed, the
amount of impervious surface area increases, the
amount of pollutants carried in the storm- water
increases, and the amount of wastewater and solid
waste requiring disposal increases. Additionally,
increased population puts increased pressure on the
living resources.
Estuaries in the Mid- Atlantic Region are being
adversely affected by human activities. Therefore,
they need active management if environmental quality
is to be sustained. The states, in conjunction with
EPA through the Chesapeake Bay Program and the
National Estuary Programs, have instituted successful
environmental management programs to address these
environmental challenges.
1950
1990
2020
Figure 2. Human population estimates for the Mid-Atlantic estuarine watershed.
Source.- Cull'iton
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Oyster harvest in the Chesapeake Bay
Photo by: Chesapeake Bay Program
polychlorinated biphenyl (PCB) concentrations.
Chlordane levels that exceed the U.S. Food and Drug
Administration action level have also been reported.
The Delmarva coastal bays are the least
degraded systems in the Mid-Atlantic Region,
but are threatened by encroaching urbanization.
These bays are moderately enriched by nutrients,
particularly in Delaware, largely from agricultural
sources. Eutrophication is increasingly noticeable in
the dead-end canals along shorelines in the
Delmarva coastal bays. SAV has historically been
absent from the Delaware coastal bays due to high
94%
natural turbidity. The composition of shore zone fish
species in the Delaware coastal bays indicates
impacted environmental conditions. In contrast, the
fish species in Maryland's coastal bays suggest
a healthy habitat; researchers have, however,
observed evidence of early stages of degradation
in northern areas.
Oyster harvests have declined from a high of
133 million pounds in 1880 to today's annual catch
of about one million pounds. Disease, specifically
Dermo and MSX, appears to be one of the major
causes of the recent drastic decline in the oyster
populations in the Chesapeake Bay and the
Delaware Estuary, with over-harvesting and
pollution also playing major roles in Chesapeake
Bay. Although no immediate solution to the problem
is known, researchers currently are working on the
concept of introducing disease-resistant strains of
oysters to the Mid-Atlantic.
The most important shellfish industry in the
Mid-Atlantic Region is now the blue crab.
However, the significantly increased fishing
pressure on this already heavily exploited resource
is beginning to take its toll. To avoid a serious
impact, both Maryland and Virginia have placed
restrictions on crabbing in Chesapeake Bay waters.
Each state monitors its estuarine waters for coliform
bacteria and closes areas that reach critical levels to
shellfishing (Figure 5), Coliform contamination
may come from sewage treatment plants, leaking
; : "•;•"••••'-, septic systems, marinas,
industry, wildlife, boating,
and runoff. Improve-
ments in wastewater
treatment have reduced
D Restricted
• Not Limited \
the acreage closed to
shellfishing from 18% in
1985 to 10% in 1995. :
Figure 5.
Shellfish closures in
Mid-Atlantic estuaries
expressed as a percent
of acreage classified as
productive grounds.
Source: NOAA, 1997
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Summary of Fish Trends Data
The striped bass fishery in Chesapeake Bay
and the Delaware Estuary is considered to be
recovering.
American shad populations are improving
region-wide.
The white perch population is stable but low in
Chesapeake Bay.
Summer flounder populations are stable or
perhaps declining in the Delaware Estuary.
Summer flounder populations are improving in
the Maryland coastal bays.
Drum species populations are variable in the
Delaware Estuary.
Shore-zone species composition suggest
degraded conditions in the Delaware coastal bays.
Shore-zone species compositions suggest
generally healthy conditions with slight
indications of degradation in the northern
coastal bays of Maryland.
In the states surrounding the estuaries of the
Mid-Atlantic, numerous species of plants and animals
are listed as threatened or endangered and virtually
every county has at least one listed species. It is
encouraging that the threatened and endangered
species directly associated with the estuaries are
improving. : " : ;"
Fish exhibiting sores caused by Pfiesteria.
Photo by: Maryland Department of Natural Resources
During the summer of 1997, a number of fish kills
occurred in several small tributaries of Chesapeake
Bay and the coastal bays. It was determined that
these kills were caused by the toxic dinoflagellate
Pfiesteria. Pfiesteria is not a disease, but an
organism that is part plant and part animal, and
occurs naturally from the Gulf of Mexico to the
Delaware Estuary. A large number of research
projects are currently underway to better understand
this organism.
I
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MAJOR FiNdi
The Chesapeake Bay is the estuary most deficient
in oxygen in the region. (Figure 3). Impacts to the
Bay are associated with nutrient over-enrichment
and the lack of dissolved oxygen. Excessive
nutrients during the 1970s and 1980s contributed to
prolonged algae blooms, which decreased dissolved
oxygen and clarity of the water. This resulted in
massive losses of submerged aquatic vegetation
(SAV), which is critical habitat for animal life in
the Bay - spawning fish, crabs, etc. Nutrient levels
are now declining in response to improved wastewa-
ter management practices, implementation of best
management practices on agricultural lands
(nitrogen), and bans on certain types of detergents
(phosphorus). The reduction in nutrients has
resulted in partial recovery of the SAV beds. There
has been more success in controlling point sources
than controlling non-point sources of nutrients.
The Delaware Estuary is impacted by the lack of
water clarity (Figure 4) and toxic contaminants
associated with urbanization and industrialization.
It has some of the largest concentrations of nutrients
measured anywhere in the world, although harmful
phytoplankton blooms and other effects traditionally
associated with nutrients are held in check by other
factors, including low water clarity. The Delaware
Estuary also has some of the highest levels of
chemical contaminants in fish and shellfish in the
nation. Portions of the estuary have bans or
advisories on consumption of fin-fish due to elevated
Water Clarity
Good
Fair
Poor
Figure 4. Summer water column clarity in
Mid-Atlantic estuarine waters as observed in 1990-
93. Water clarity categories are poor (red), fair
(yellow), and good (green), which are defined in
the Technical Appendix of the full report.
Sources: Strobel et al., 1995; Paul et al., 1997
Graph Sources: Strobel eta/., 1995; Paul et al., 1997
Map Sources: Chaillou etal., 1996; CBP, 1997; USEPA, 1995; Magnien elal.
*. - -
Figure3. Distribution of summer-
time dissolved oxygen within one
meter of bottom sediments across
estuarine waters in the Mid-Atlantic
Region. Categories are defined in the
Technical Appendix of the full
report. Data were derived from
daylight observations and do not
necessarily reflect night time depres-
sions that may occur in some areas.
Map depicts spatial distribution
derived from multiple sources of
information. Bar graph shows percent
areas derived from EPA EMAP
1990-93 data.
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Summary of ecological conditions across the Mid-Atlantic estuaries. Colors represent the best estimate of
condition based upon information presented in the report—green for good condition, yellow for a moderate problem, ,
and red for a problem. A lack of color indicates that inadequate information was available. Where multiple colors are
shown, our best estimate is that condition ranges between the two categories. Problem areas are determined by
individual indicator values. The table does not imply that problem areas are always man-induced.
Mid-Atlantic
Reaion
Chesapeake Bay I Delaware Estuary
Coastal Bays
DE MD VA
Mainstem Tributaries
Water quality: nutrients
Water quality;
phytoptenkton
Watar quairty: dissolved
oxygon
Sediment contamination
Habitat; coastal wetlands
Habitat: submerged'
aquatic vegetation
uvtng resources:
benthos
Living resources:
sheiifish harvest (oyster)
Living resources:
shellfish harvest (crab)
Living resources:
shellfish closures
Living resources: fish
stock
Living resources:
contaminants hi fish/
shellfish
Living resources;
disease (fish)
Living resources:
disease (shellfish)
Living resources:
waterfowl
Living resources:
threatened/endangered
species
cxEPA
John F.Paul
U.S. Environmental Protection Agency
NHEERL, Atlantic Ecology Division
Narragansett, RI 02882
, paul.john@epa.gov
M. Patricia Bradley
U.S. Environmental Protection Agency
Environmental Science Center
Ft. Meade, MD 20755-5350
bradley.patricia@epa.gov
«"«-"l-"«» '"'""Tom'TDeMoss "' '' '
U.S. Environmental Protection Agency
Environmental Science Center
Ft. Meade, MD 20755-5350
! tcimfS)etia."'
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