Penny Lane Shellfish Study

A Shellfish Study for the Proposed Floating Personal
Water Craft Dock System and Fixed Access Dock at
Penny Lane Marina, Margate, NJ.

Survey Conducted For:

Penny Lane Marina
Roy Goldberg, Owner
9420 Amherst Avenue
Margate, New Jersey 08402

Survey Conducted By:

Richard Stockton College of New Jersey’s
Coastal Research Center
30 Wilson Avenue
Port Republic, NJ. 08241
(609) 652-4245
November 18th & 19th, 2010

Penny Lane 1

A Shellfish Study for the Proposed Floating Personal Water Craft
Dock System & Fixed Access Dock at Penny Lane Marina
9420 Amherst Avenue, Margate, Cape May County, New Jersey
November 18th & 19th, 2010

Introduction

The shellfish study was designed and implemented using the Shellfish Survey Guidelines
published by the New Jersey Department of Environmental Protection (NJDEP) as authorized by
Jeffrey C. Lockwood, 1991 National Marine Fisheries Service, Habitat and Protected Resources
Division. The proposed development of Penny Lane Marina includes two main floating docks
and 51 Jet Ski ports. The dock would extend 250 feet from the existing bulkhead along Amherst
Avenue (in the northwest to southeast direction), and is approximately 75 feet wide. The
proposed marina is bordered on both sides by existing dock structures. The bay floor slopes
from a depth at the bulkhead of -5.0 out to a depth of -30.0 feet NAVD 88. The target species is
the Hard Clam (Mercenaria mercenaria) a shellfish of commercial and biological significance.

Methods and Materials

The study area was selected by analyzing the area of the proposed marina and evenly distributing
the entire study area into uniform sub-sections (chart 1). The range of water depths was from -
5.0 to -30.0 feet below the North American Vertical Datum of 1988 shown in McLarnon’s
USACOE Permit Plan.

Using ESRI ArcGIS 9.3.1 a virtual grid was set up in the same approximate position of the
proposed dock system with corresponding known locations at each of the intersections of the
grid totaling 24 points (charts 1 and 2). These points within the grid served as the locations for
both the juvenile and adult clam survey. Twelve locations were used for the juvenile clam
survey and twelve for the adult clam survey. The distance between points in both the adult and
juvenile clam survey is 25 feet. Using the Leica RTK GPS system 1200, the positions of all the
data points for both the juvenile clam study and the adult clam raking study were obtained.

To conduct the juvenile clam study the 12 data point locations stored on the GPS system were
used as waypoints to locate each sample site (chart 1, table 5). At each location, a single anchor
was set to help stabilize the boat. A Wildco Ponar grab sample; with an area of 0.75 sq. ft., was
used to acquire the samples. Replicate grabs were often necessary to obtain a full sample size.
Once a full sample was obtained, the material was sifted through a 5mm sieve and inspected for
juvenile clams. This process was repeated at each individual location. Additional variables such
as sediment type, additional bivalve mollusks, as well as aquatic vegetation were also noted at
each site. At each location the abundance per square foot (ft2) and size distribution (mean and
range) were also reported (tables 1 and 3).

To conduct the adult clam rake study, site locations stored on the GPS were again used to
navigate to the pre-established locations (chart 1, table 6). At each location two anchors were
set, one at the bow and one at the stern. The anchor lines were let out equally and incrementally
in 10’ sections. Each 10’ section was raked using a 16” x 3” toothed bull rake at each location
until a 30’ transect distance was achieved. Additional variables such as sediment type, other
bivalve mollusks, as well as aquatic vegetation were also noted at each site. At each location, the
abundance per ft2 and size distribution (mean and range) was also reported (Tables 2 and 4).

Penny Lane 2

Results – juvenile shellfish survey

As reported above the study area was sampled for juvenile shellfish by utilizing a Wildco Ponar
Grab Sample with an area of 0.75 sq. ft. Twelve sites were established and sampled representing
the area of the proposed marina. Zero juvenile Hard Clam (Mercenaria mercenaria) were found
in the study area. A total of 9 sq. ft. was sampled with an overall density of 0 clams/sq. ft. The
sedimentology of the area consisted of very fine black sand with silt, black silt with sand, or fine
black sand with silt. There were only 2 major species of aquatic vegetation at all of the locations
surveyed, Sea Lettuce (Ulva lactuca) and Agardh’s Red Weed (Agardhiella tenera). A total of,
17 Long-Clawed Hermit Crabs (Pagurus longicarpus), 8 Mud Dog Whelks (Nassarius
obsoletus), 2 Juvenile Blue Crab (Callinectes sapidus), 2 Blue Mussels (Mytilus edulis), and 1
Blood Ark (Anadara ovalis), were found in the process of locating juvenile Hard Clams (tables 1
and 3).

Results – adult shellfish survey

As reported above the study area was sampled using a 16” x 3” toothed bull rake. A total of 3
Hard Clams (Mercenaria mercenaria) were found in the entire area which consisted of 12
individual sites approximately 25 feet from each other respectively. Each site was raked a
distance of 30’. Clams were found in 2 of the 12 sites. A total of 479.88 square feet was raked
with an overall density of 0.0062 clams/sq. ft. The mean size of the clams collected was 7.73cm
with an overall range from 5.6 to 10.0 cm. The sediments in the area consisted of very fine black
sand with silt, or black silt with sand. There was only 1 major species of aquatic vegetation at all
of the locations surveyed, Sea Lettuce (Ulva lactuca). One Common Spider Crab (Libinia
emarginata) was found in the process of locating adult Hard Clams (tables 2 and 4).

Conclusion

The study area at 9420 Amherst Avenue, Margate, Atlantic County, NJ is the location of the
proposed development of Penny Lane Marina. The area was surveyed by utilizing ArcGIS
software, GPS equipment, grab sampling techniques, and a clam rake to help isolate the Hard
Clam (Mercenaria mercenria). According to The NJAC’s Coastal Zone Management Rules “a
shellfish habitat area is defined as an area which… has a current shellfish density equal to or
greater than 0.20 shellfish per square foot”. Both the juvenile and the adult clam study had
densities below the cited threshold. The juvenile clams (those surveyed with the 5mm sieve
screen) produced a value averaged across the total surface area sampled by the ponar grab
samples (9.0 ft2) at 0 clams per square foot. The adults recovered in the clam rake that covered
479.88 square feet yielded 0.0062 clams per square foot. These numbers indicate that the clam
density within the area delineated for the installation of a personal water craft dock system and
fixed access dock at Penny Lane Marina does not substantiate a viable Hard Clam habitat.

Penny Lane 3

Water Quality Characteristics for Penny Lane,
Margate, NJ.
Site of the Proposed Marina Development

Temperature, Salinity, Dissolved Oxygen, Depth, pH, Specific Conductivity, and Turbidity Data for
(Mercenaria mercenaria), Hard Clam Populations

Introduction:

The Richard Stockton Coastal Research Center (CRC) completed a juvenile and adult hard clam
study for the proposed development of Penny Lane Marina, Margate, NJ in November 2010.
Twenty four sites were raked and grab samples were taken for juvenile and adult hard clams. In
this study, no juvenile clams were observed and just 3 adult clams were obtained within 480
square feet of space raked in the project area. A water quality assessment was also included in
the proposal based on the follow variables: temperature, salinity, dissolved oxygen, depth, pH,
specific conductivity, and turbidity for the water just above the sediment surface.

Water Quality at the Site:

The CRC complied the data on November 18th & 19th 2010 with a study of the water quality
parameters for the 24 sites subjected to clam raking or grab sampling using a YSI water quality
probe to obtain the results listed in table 7, below. The table lists the site location using the same
designations used in the clam study. The dissolved oxygen values are shown as both a percentage
of the maximum level in seawater and as milligrams per liter of water. The depth of
measurement at the mid-tidal elevation stage the work was done is also listed. The specific
conductivity is given as well although the salinity is the most common expression of the salt
content of the water.

Conclusions:

The temperature is normal for the time of year within the bay environment of Atlantic County.
The salinity is also within normal ranges for mid-tide conditions behind the barrier island,
however, the average value failed to fall within the optimal range for the Hard Clam of 26.5 to
27.5 ppt. The dissolved oxygen levels are excellent with average values of 8.74 mg/L, and
95.6% respectively. The pH value of 7.94 is within the normal range for all stages of Hard Clam
development. None of the remaining water quality parameters including depth, specific
conductivity, and turbidity, would dictate that Mercenaria mercenaria could not live in the
waters of the proposed development of Penny Lane Marina (see appendix at end).

Penny Lane 6

Table 1: Grab Samples Used to Determine the Density of Juvenile Hard Clams

Transect Juvenile Clams (live) (mm) Other Shellfish Observations Hard Clam Density Mean Range
J1 - - Adult Hard Clam Shell, 2 Juvenile Blue Claw Crabs - - -

4 Mud Dog Whelk (Nassarius obsoletus ), 2
Long-Clawed Hermit Crabs (Pagurus 1 Shrimp, Adult Hard Clam Shells, 1 Juvenile Hard
J2 - - - -
longicarpus ), 2 Juvenile Blue Crab (Callinectes Clam Shell
sapidus) , 1 Blook Ark (Anadara ovalis )

J3 - 3 Mud Dog Whelk (Nassarius obsoletus) 1 Shrimp - - -
J4 - 1 Mud Dog Whelk (Nassarius obsoletus) Mussel Shells - - -
J5 - - - - - -
J6 - - - - - -
J7 - - Mussel Shells - - -
J9 - - Mussel Shells

3 Long-Clawed Hermit Crabs (Pagurus
J10 - - - - -
longicarpus )

J11 - - - - -
longicarpus )
J12 - Mussel Shells - - -

J13 - longicarpus ), 2 Adult Blue Mussels (Mytilus - - - -
edulis)

J14 - Mussel Shells - - -
longicarpus )


Penny Lane 7

Table 2: Rake Samples of 12, 30-foot Traverses within development Site

Transect Adult Clams (live) (cm) Clams Per Site Other Shellfish Observations Transect Length Hard Clam Density Mean (cm) Range (cm)
A1 0 2 Adult Hard Clam shells 30' 0 - -
A2 0 30' 0 - -
A3 0 1 Adult Hard Clam Shell 30' 0 - -
A4 0 30' 0 - -
A5 0 30' 0 - -
A6 7.6, 10.0 2 2 Adult Hard Clam shells 30' 0.05 8.8 2.4
A7 5.6 1 30' 0.025 - -
A8 0 30' 0 - -
A9 0 30' 0 - -
1 Adult Common Spider Crab
A10 0 Mussel Shells 30' 0 - -
(Libinia emarginata )
A11 0 30' 0 - -
A12 0 36 Mussel Shells 30' 0 - -
479.88 sq. ft. sampled, 3 adult Hard Clams = 0.0062 clams/sq. ft.

Penny Lane 8

Table 3: Aquatic Vegetation & Sediment Type / Grab Sample

Site # Species & viability of aquatic vegetation Sediment
J1 no vegitation found Very Fine Sand with Silt, Black
J2 Minimal amounts of Sea Lettuce (Ulva lactua ) Very Fine Sand with Silt, Black
J5 Minimal amounts of Sea Lettuce (Ulva lactua ) Silt with Sand, Black
J8 no vegitation found Fine Sand with Silt, Black
J10 Minimal amounts of Sea Lettuce (Ulva lactua ) Very Fine Sand with Silt, Black
J12 no vegitation found Silt with Sand, Black

Penny Lane 9

Table 4: Aquatic Vegetation & Sediment Type / Rake Sample

Site # Species & viability of aquatic vegetation Sediment
A1 Minimal amounts of Sea Lettuce (Ulva lactua ) Very Fine Sand with Silt, Black
A2 Minimal amounts of Sea Lettuce (Ulva lactua) Very Fine Sand with Silt, Black
A3 no vegitation found Very Fine Sand with Silt, Black
Minimal amounts of Sea Lettuce (Ulva lactua ), and Agardh's Red
A5 Very Fine Sand with Silt, Black
Weed (Agardhiella tenera )
A6 no vegitation found Silt with Sand, Black

Minimal amounts of Sea Lettuce (Ulva lactua ), and Agardh's Red
A7 Very Fine Sand with Silt, Black
Weed (Agardhiella tenera )

A8 no vegitation found Silt with Sand, Black
A9 Minimal amounts of Sea Lettuce (Ulva lactua ) Silt with Sand, Black
A11 Minimal amounts of Arardh's Red Weed (Agardhiella tenera ) Very Fine Sand with Silt, Black

Penny Lane 10

Table 5: Penny Lane Shellfish Study Table 6: Penny Lane Shellfish Study
11/18/2010 Juvenile Clam Survey Points 11/19/2010 Adult Clam Survey Points

Transect Easting Northing Transect Easting Northing
J1 486801.20 179114.28 A1 486777.12 179065.83
J2 486780.99 179100.91 A2 486797.34 179081.28
J3 486761.67 179087.53 A3 486817.55 179093.77
J4 486771.48 179156.50 A4 486746.80 179107.15
J5 486750.07 179142.82 A5 486767.61 179120.82
J6 486730.15 179127.66 A6 486787.23 179136.28
J7 486739.67 179197.23 A7 486715.59 179147.28
J8 486719.75 179184.44 A8 486735.50 179162.74
J9 486699.83 179169.88 A9 486756.31 179177.31
J10 486708.45 179239.44 A10 486684.37 179189.50
J11 486687.94 179225.77 A11 486705.78 179204.36
J12 486669.51 179211.20 A12 486725.69 179219.82

Penny Lane 11

Table: 7 Penny Lane Marina Shellfish Study Water Quality Data

Temperature Salinity Dissolved Oxygen Dissolved Oxygen Depth Specific Conductivity Turbidity
Site (Celsius) (ppt) (as a %) (mg/L) (feet) pH (mS/cm) (NTU)
A1 11.27 28.96 95.6 8.84 0.100 7.91 44.91 6.00
A2 11.25 28.94 91.0 8.23 0.589 7.89 44.91 5.10
A3 11.22 28.94 95.6 8.57 0.791 7.76 44.87 5.30
A4 10.70 29.80 97.0 8.99 1.560 7.98 46.11 4.90
A5 10.71 29.76 96.7 8.97 1.833 7.98 46.07 8.60
A6 10.66 29.67 101.3 9.15 1.869 7.98 45.94 5.40
A7 10.65 29.57 99.2 8.98 2.090 7.98 45.80 5.00
A8 10.62 29..59 97.2 8.95 1.916 7.98 45.85 5.30
A9 10.63 29.57 96.4 8.83 3.492 7.97 45.83 5.80
A10 10.60 29.49 98.3 9.09 4.492 7.99 45.71 6.20
A11 10.60 29.49 95.8 8.89 6.234 7.98 45.71 6.10
A12 10.61 29.49 98.6 9.10 4.828 7.99 45.71 6.20
J1 11.11 29.23 93.5 8.46 0.492 7.92 45.30 6.20
J2 11.21 29.03 93.1 8.58 0.124 7.92 45.03 5.30
J3 11.11 29.01 94.1 8.66 0.324 7.90 45.00 6.10
J4 11.31 29.09 97.3 8.66 6.903 7.94 45.10 5.20
J5 11.34 28.91 96.1 8.55 4.353 7.95 44.81 5.30
J6 11.36 28.43 95.8 8.90 2.151 7.95 44.20 5.90
J7 11.27 29.13 95.3 8.44 7.581 7.94 45.15 6.40
J8 11.19 29.11 95.2 8.76 7.877 7.94 45.13 7.00
J9 11.14 29.14 95.8 8.63 5.503 7.95 45.18 7.60
J10 11.11 29.33 90.7 8.38 11.469 7.95 45.44 6.60
J11 11.11 29.17 91.6 8.40 11.270 7.95 45.23 9.60
J12 11.13 29.24 94.6 8.70 6.465 7.95 45.32 5.90

Avg. 11.00 29.24 95.66 8.74 3.93 7.94 45.35 6.13

Penny Lane 12

References

1. J. C. Lockwood, “Shellfish Survey Guidelines”, National Marine Fisheries Service,
Habitat and Protected Resources Division, Highlands, N.J., 1991.

2. N.J.A.C., “Coastal Zone Management Rules”, 7:7E-3.2, 19-22, (2009).

3. R. D. McLarnon, PE., “Penny Lane Associates USACOE Permit Application Plan”,
(2010).

Penny Lane 13

APPENDIX OF LITERATURE FOUND DISCUSSING HARD CLAM HABITAT
PARAMETERS
The References Below Cover Specific Parameters for Mercenaria mercenaria clams

1. ER-L and ER-M sediment quality guideline values are from Long et al. (1995) and Long
and Morgan (1990). TEL and PEL sediment quality guidelines are from MacDonald (1994) and
MacDonald et al. (1996). Unacceptable DO: any observation with DO < 0.3 mg/l, or 20% or
more time-series observations < 2 mg/l, or all time-series observations < 5 mg/l.

2. Northern quahog Mercenaria mercenaria abundance and habitat use in
Chesapeake Bay

Journal of Shellfisheries Research, August, 2005 by Roger
Mann, Juliana M. Harding, Melissa J. Southworth, James A.
Wesson
Clam densities decreased significantly across the four types of substrate with the highest
densities observed in shell substrate followed by sand, mud and anoxic muds in order of
decreasing occupation (Kruskal Wallis, H = 1,414.27, DF = 3, P < 0.01; Fig. 3). Less than 1% of
all clams collected were from anoxic mud substrates whereas shell, sand, and mud substrates
contained 11%, 68% and 21% of clams, respectively. Although shell and sand substrates
contained the highest observed densities of hard clams, these substrate types were only present in
38% of patent tong samples collected from potential clam habitats.

3.

Abundance:
In the IRL as in other areas within its range, Mercenaria mercenaria is most abundant in shell-
containing soft bottoms. They are also found (in decreasing order of abundance) on sand flats,
sand/mud flats and on muddy bottoms (Wells 1957; Pratt 1953). A study by Peterson et al.,
(1984) also showed that densities of 0 - 2 year old hard clams in eelgrass (Zostera marina) beds
of North Carolina was more than 5 times the average density of clams in nearby sand flats (9 per
square meter in eelgrass, vs. 1.6 per square meter in nearby sand flats. Further, hard clams from
Zostera beds appeared to be somewhat larger, on average, than those from sand flats.
Hydrodynamic baffling by seagrasses may be at least partially responsible for the observed result
(Peterson et al., 1984). Reduction in currents near the benthos enhances the deposition of fine
sediments and suspended materials between blades of seagrass, especially near patch edges.
Hydrodynamic baffling therefore provides a rich food source for juvenile clams.

Penny Lane 14

4. FWS/OBS-82/10,77
AUGUST 1984
HABITAT SUITABILITY INDEX MODELS: HARD CLAM
Rosemarie Mulholland
Florida Cooperative Fish and Wildlife Research Unit
U.S. Fish and Wildlife Service
School of Forest Resources and Conservation
117 Newins-Ziegler
University of Florida, Gainesville, FL 32611

SPECIFIC HABITAT REQUIREMENTS:
Embryo, Larva, Juvenile

pH. Calabrese (1972) observed that the successful recruitment of mercenaria requires that
the pH of estuarine waters not fall below 7.0; he found no significant decrease in the number of
clam embryos developing normally within the pH range of 7.0-8.75, but that number was greatly
reduced at pH 9.0. Survival of clam larvae was normal at pH 6.25-8.75, but the range for normal
growth was 6.75-8.50. Although clam larvae can survive at pH 6.25, a pH of 7.0 is required for
normal development of the embryo. Levels of pH below 7.0 limit recruitment of the species
(Calabrese 1972).

Dissolved oxygen. Morrison (1971) found that growth of shelled veligers of M. mercenaria was
normal when dissolved oxygen concentration was 4.2 mg/l or greater. Growth essentially ceased
at concentrations of 2.4 mg/l and less. Larvae survived extended exposures (14 days) to 1 mg/l
dissolved oxygen but grew little. Prolonged exposure to levels of less than 4.0 mg/l lengthened
the clam's planktonic stage and decreased its probability of survival. Embryos developed
normally at oxygen levels as low as 0.5 mg/l; however, 100% mortality occurred at 0.2 mg/l.
Fluctuations in dissolved oxygen do not affect adult hard clams as much as do fluctuations in
temperature and salinity (Stanley and DeWitt 1983). The burrowing ability of M. mercenaria was
neither severely nor permanently impaired by exposure to reduced oxygen levels (less than
1mgl1 seawater) for up to 3 weeks (Savage 1976). Pratt and Campbell (1956) found no
correlation between growth rates and various concentrations of dissolved oxygen. All life stages
tolerate nearly anoxic conditions for long periods, though they may cease growing (Stanley and
DeWitt 1983).

Salinity. Salinity appears to be most critical for M. mercenaria during the egg and larval stages
(Stanley and DeWitt 1983). At Long Island Sound, New York, eggs developed into straight-
hinged veligers only within the relatively narrow salinity range of 20.0 to 32.5 parts per thousand
(ppt ), The optimum for development of clam eggs was about 26.5 to 27.5 ppt (Davis 1958).
Growth of larvae, once they attained the straight-hinged stage, was comparatively good at
salinities as low as 20 ppt (Davis 1958), but Chanley (1958) found that growth of juvenile M.
mercenaria was retarded at salinities of 22.5 ppt or lower. Castagna and Chanley (1973) found
that metamorphosis of M. mercenaria from veliger to seed clam (byssal plantigrade stage) was
inhibited below 17.5 to 20 ppt.

Temperature. Davis and Ca1abrese (1964) noted that 1aboratory-rea red straight-hinged

Penny Lane 15

veligers of M. mercenaria were capable of ingestion, but not digestion, at 10°C (50°F),- and
consequently did not grow. Growth was positively related to temperature at 18.0° to 30.0°C (64°
to 86°F). Growth of straighthinged veligers of M. mercenaria was little affected by temperature
differences within the range of 20° to 30°C (68° to 86°F). Although the optimum temperature for
growth of M. mercenaria larvae was not well defined, growth was optimum at the following
temperature/salinity combinations: 30°C (86°F)/22.5 ppt and higher, 27.5°C (81.5°F)/17.5 and
20.0 ppt, and 25°C (77°F)/15.0 ppt.

Substrate. The nature of the bottom substrate seems to be the main factor responsible for
settling of larvae and for the qualitative composition of bottom communities (Thorson 1955).
Keck et ale (1974) reported from laboratory studies that significantly higher (P ~ 0.05) numbers
of M. mercenaria larvae set in sand than in mud; they suggested that the addition of organic
material to the sediment may be responsible for reduced setting because of increased bacteria
levels, reduced dissolved oxygen, and increased production of hydrogen sulfide. Carriker (1959)
recommended that the substrate be firm and free of excessive organic mud for larval clam
culture; muddy bottoms can be surfaced with shells, sand, or gravel. Adult Clams were most
abundant in predominantly fine sediments, but in these sediments their abundance was generally
a function of the coarseness of the minor constituents. Clams do not grow well in silty substrates.
Pratt and Campbell (1956) found an inverse relationship between growth of M. mercenaria and
the fineness of the sediment (expressed as percentage of silt and clay). The inferior growth was
attributed to frequent gi1l clearing, which expended energy and interfered with feeding. Johnson
(1977) also reported slower growth of M. mercenaria in finer sediment due to increased
expulsion of pseudofeces.

Suspended solids. Davis (1960) noted that both the larvae and egg stage are affected by
suspended solids. “Eggs did not develop correctly at silt concentrations of 3.0 or 4.0 g/L, and
straight-hinged veligers was normal at silt concentrations of 0.75g/L, retarded at 1.0 to 2.0g/L,
and negligible at 3.0 and 4.0g/L.”

Penny Lane Shellfish Study

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