NATIONAL
ESTUARY
PROGRAM
EFFECTS OF ARTIFICIAL SHORELINES
Natural shorelines, including marshes and beaches, are critical for maintaining the ecological health of estuaries by stabilizing the shoreline, reducing
erosion, and providing critical habitat for commercially and ecologically important aquatic species. Over the past 30 years, Barnegat Bay has lost a greater
percentage of natural shoreline to coastal development than have other estuaries in the mid-Atlantic region. Specifically, 36% of the natural shoreline in
Barnegat Bay has been bulkheaded—replaced by watershed retaining barriers—representing a significant loss of natural habitat, particularly marshes and
estuarine beaches.
Bulkheads extend out from the original shoreline, altering the flow of water and the deposition of sediments, especially fine sand and silt. This often leads to decreased water clarity
and quality. Bulkheads also eliminate shallow aquatic habitats that are especially important as refuge areas for small organisms and the juveniles of large organisms. As a result,
the areas in front of bulkheads typically have a reduced abundance and diversity of organisms that live on the bottom and in the water column. In the United States, most research
on the effects of bulkheads has been done along the West Coast. There is little information on how bulkheads affect aquatic habitats or organisms in New Jersey estuaries.
THE NATIONAL ESTUARY PROGRAM IN ACTION
Barnegat Bay National Estuary Program
In the summer of 2006, with
funds from the Barnegat Bay Na-
tional Estuary Program, research
was conducted by Rider Univer-
sity to compare the sediment
characteristics, depth profiles,
species diversity, and abundance
offish and decapods (e.g., crabs
and shrimp) in front of bulkheads
and two types of natural shore-
lines (marsh and beach) in the
Little Egg Harbor portion of
Barnegat Bay.
In the summer of 2007, the
study was expanded throughout
Barnegat Bay. Sampling site se-
lection took into account the ex-
tent of coastal development sur-
rounding the sampling sites, and
photographs from the 1920s and
1950s were used to account for
"bulkhead history" - the type of
natural shoreline the current
bulkheads replaced. As a result,
an equal number of bulkheads
that replaced marshes and
beaches were sampled in each
section of the Bay.
Some important physical char-
acteristics of the habitats in front
of bulkheads were very different
from natural shoreline habitats.
Sediment composition differed
among the shoreline types: bulk-
heads contained more of the
largest-sized sediment than ei-
ther beaches or marshes, and
bulkhead shorelines contained
EFFECTIVE
EFFICIENT
ADAPTIVE
COLLABORATIVE
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far less of the smallest-sized
sediment than did marshes.
These changes in sediment
characteristics are consistent
with more turbulent water flow
in front of bulkheads as com-
pared to the natural shorelines.
They influence the abundance
and diversity of bottom-dwelling
organisms by discouraging or-
ganisms that bury in fine sedi-
ments or that prey on buried or-
ganisms from occupying habitats
in front of bulkheads. Faunal
communities along bulkheads
differed from those of natural
shorelines. In each section of the
estuary sampled, the total num-
ber of organisms such as fish,
crabs, and shrimp at the bulk-
heads was lower than at either
type of natural shoreline. On
several occasions, nothing was
caught in front of bulkheads.
Species diversity was also con-
sistently lower in front of bulk-
heads. The composition of the
individuals captured in front of
bulkheads suggests that bulk-
heads are poor refuge areas for
small prey species and the juve-
niles of larger predators. Several
small prey species that were
never caught in front of bulk-
heads, including blueback her-
ring, killifishes, menhaden, na-
ked goby, striped mullet, and
sheepshead minnow, were cap-
tured at the natural shorelines.
Habitats in front of bulkheads
are significantly deeper than
those of natural shorelines, and
are characterized by larger indi-
viduals of both prey and preda-
tor species. Individuals of five
prey species (alewife, anchovy,
silverside, grass shrimp, and
sand shrimp) were captured at
all shoreline types. Individuals of
three of those species were sig-
nificantly larger in front of bulk-
heads than at either natural
shoreline. Individuals of nine
predator species (black drum,
bluefish, northern kingfish,
northern pufferfish, silver perch,
summer flounder, tautog, weak-
fish, and winter flounder) were
captured at all shoreline types
and, on average, individuals of
four of those species were sig-
nificantly larger in front of bulk-
heads than at either natural
shoreline.
These findings suggest that
bulkhead habitats are not as bio-
logically rich as natural shoreline
habitats and may function differ-
ently. In addition, if current sea-
level-rise scenarios for the mid-
Atlantic are accurate, bulkheads
may accentuate the negative ef-
fects of sea-level rise on nursery
habitats in Barnegat Bay.
Visit www.bbnep.org to learn
more about this and other BBNEP
efforts.
EPA's National Estuary Program
(NEP) is a unique and successful
coastal watershed-based program
established in 1987 under the
Clean Water Act Amendments.
The NEP involves the public and
collaborates with partners to pro-
tect, restore, and maintain the wa-
ter quality and ecological integrity
of 28 estuaries of national signifi-
cance located in 18 coastal states
and Puerto Rico.
For more information about the
NEP go to www.epa.gov/owow/
estuaries.
The NEP: Implementing the Clean Water Act in ways that are Effective, Efficient, Adaptive, and Collaborative.
EPA-842F09001
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