A shellfish study was conducted at All Seasons Marina in New Jersey to assess the impact of a proposed breakwater expansion on hard clam populations. Sampling of juvenile and adult clams found densities well below the threshold to constitute viable shellfish habitat. The report concluded that the clam density in the area of the proposed breakwater does not substantiate the area as viable hard clam habitat.

1. A Shellfish Study for the Proposed Timber Breakwater at All Seasons Marina
551 Roosevelt Boulevard, Marmora, Cape May County, New Jersey
March 9, 2010
Survey Conducted For:
All Seasons Marina
Brian Tersaga, Owner
551 Roosevelt Boulevard
Marmora, New Jersey 08223
Survey Conducted By:
Richard Stockton College of New Jersey’s
Coastal Research Center
30 Wilson Avenue
Port Republic, NJ. 08241
(609) 652-4245
March 9, 2010

2. All Seasons 1
A Shellfish Study for the Proposed Timber Breakwater at All Seasons Marina
551 Roosevelt Boulevard, Marmora, Cape May County, New Jersey
March 9, 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 expansion to the All Seasons Marina includes a timber breakwater
which would be positioned 464 feet from the existing bulkhead near the showroom building.
The breakwater would extend 600 feet in the northwest to southeast direction, thereby sheltering
the marina from northeast winds. The marina is fringed by salt marsh vegetation, and includes a
muddy intertidal flat, which slopes gently into a sub-tidal habitat, and out to a depth of -5.0 feet
Mean Low Water (MLW). The target species is the Hard Clam (Mercenaria mercenaria) a
shellfish of commercial significance.
Methods and Materials
The study area was selected by analyzing the area of the proposed breakwater and evenly
distributing the entire study area into uniform sub-sections (chart 1). The range of water depths
was from -1.0 to -5.0 feet below the Mean Low Water reference datum shown in the Ecker’s
USACOE Permit Plan.
Using ESRI ArcGIS 9.3.1 a virtual line was set up with corresponding known locations along a
700 foot line in the position where the proposed breakwater would be. There were a total of 16
equally spaced points established along the line which will serve as the locations for the clam
survey. Eight locations will be used for the juvenile clam survey and eight for the adult clam
survey. The distance between points in both the adult and juvenile clam survey is 87.5 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 8 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).

3. All Seasons 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. Eight sites were established and sampled representing
the area of the proposed breakwater. Zero juvenile Hard Clam (Mercenaria mercenaria) was
found in the study area. A total of 6 sq. ft. was sampled with an overall density of 0 clams/sq. ft.
One adult Hard Clam (Mercenaria mercenaria) was found at transect J3 and was 5.5cm. The
sedimentology of the area consisted of either black mud, or very fine sandy mud. 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 64 Mud Dog Whelks
(Nassarius obsoletus) were found in the process of locating juvenile Hard Clams.
Results – adult shellfish survey
As reported above the study area was sampled using a 16” x 3” toothed bull rake. A total of 4
Hard Clams (Mercenaria mercenaria) were found in the entire area which consisted of 8
individual sites approximately 87 feet from each other. Each site was raked a distance of 30’.
Clams were found in 3 of the 8 sites. A total of 319.92 square feet was raked with an overall
density of 0.012 clams/sq. ft. The mean size of the clams collected was 8.33cm with an overall
range from 7.5 to 8.9 cm. The sediments in the area consisted of either black mud, or very fine
sandy mud. There was only 1 major species of aquatic vegetation in all of the locations
surveyed, Sea Lettuce (Ulva lactuca).
Conclusion
The study area at All Seasons Marina, Marmora, Cape May County, NJ is the location of a
proposed breakwater installation. 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 (6.0 ft2) at 0 clams per square foot. The adults recovered in the clam rake that covered
319.92 square feet yielded 0.012 clams per square foot. These numbers indicate that the clam
density within the area delineated for the installation of a Breakwater at All Seasons Marina does
not substantiate a viable Hard Clam habitat.

4. All Seasons 3

5. All Seasons 4
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 0 24 Mud Dog Whelk (Nassarius obsoletus ) Mussel & Oyster Shells 0 clams/sq. ft. n/a n/a
J2 0 12 Mud Dog Whelk (Nassarius obsoletus) Mussel & Oyster Shells 0 clams/sq. ft. n/a n/a
J3 0 4 Mud Dog Whelk (Nassarius obsoletus) One Adult Hard Clam 5.5cm 0 clams/sq. ft. n/a n/a
J4 0 2 Mud Dog Whelk (Nassarius obsoletus) Mussel, Oyster, and Slipper Shells 0 clams/sq. ft. n/a n/a
J5 0 5 Mud Dog Whelk (Nassarius obsoletus) - 0 clams/sq. ft. n/a n/a
J6 0 5 Mud Dog Whelk (Nassarius obsoletus) - 0 clams/sq. ft. n/a n/a
J7 0 7 Mud Dog Whelk (Nassarius obsoletus) - 0 clams/sq. ft. n/a n/a
J8 0 5 Mud Dog Whelk (Nassarius obsoletus) - 0 clams/sq. ft. n/a n/a
6 sq. ft. sampled, 0 Juvenile Hard Clam = 0 clams/sq. ft.

6. All Seasons 5
Table 2: Rake Samples of 8, 30-foot Traverses within Breakwater Expansion Site
Transect Adult Clams (live) (cm) Clams Per Site Other Shellfish (live) Observations Transect Length Hard Clam Density Mean (cm) Range (cm)
A1 8.2, 9.6 2 0 Clam shells 30' 0.05 8.9 1.4
A2 8.6 1 0 Clam , Oyster, & Blood Ark Shells 30' 0.025 8.6 n/a
A3 0 0 0 - 30' 0 n/a n/a
A4 0 0 0 Mussel Shells 30' 0 n/a n/a
A5 0 0 0 - 30' 0 n/a n/a
A6 7.5 1 0 Oyster Shells 30' 0.025 n/a n/a
A7 0 0 0 Scallop & Clam Shells 30' 0 n/a n/a
A8 0 0 0 Blood Ark Shells 30' 0 n/a n/a
319.92 sq. ft. sampled, 4 adult Hard Clams = 0.012 clams/sq. ft.

7. All Seasons 6
Table 3: Aquatic Vegetation & Sediment Type / Grab Sample
Site # Species & viability of aquatic vegetation Sediment
J1 Minimal amounts of Sea Lettuce (Ulva lactuca) Very Fine Sandy Mud
J2 No vegetation found Black Mud
J3 No vegetation found Black Mud
J4 No vegetation found Black Mud
J5 No vegetation found Black Mud
J6 No vegetation found Black Mud
J7 Minimal amounts of Agardh's Red Weed (Agardhiella tenera) Black Mud
J8 Minimal amounts of Agardh's Red Weed (Agardhiella tenera) Very Fine Sandy Mud
Table 4: Aquatic Vegetation & Sediment Type / Rake Sample
Site # Species & viability of aquatic vegetation Sediment
A1 No vegetation found Very Fine Sandy Mud
A2 Minimal amounts of Sea Lettuce (Ulva lactua) Black Mud
A3 Minimal amounts of Sea Lettuce (Ulva lactua) Black Mud
A4 No vegetation found Black Mud
A5 No vegetation found Black Mud
A6 No vegetation found Black Mud
A7 Minimal amounts of Sea Lettuce (Ulva lactua) Black Mud
A8 No vegetation found Very Fine Sandy Mud

8. All Seasons 7
Table 5: All Seasons Marina Shellfish Study Table 6: All Seasons Marina Shellfish Study
3/9/2010 Juvenile Clam Survey Points 3/9/2010 Adult Clam Survey Points
Transect Easting Northing Transect Easting Northing
J1 455819.93 154156.64 A1 455784.87 154187.44
J2 455890.04 154095.03 A2 455854.98 154125.84
J3 455960.15 154033.43 A3 455925.09 154064.23
J4 456030.26 153971.82 A4 455995.21 154002.62
J5 456100.38 153910.21 A5 456065.32 153941.02
J6 456170.49 153848.61 A6 456135.43 153879.41
J7 456240.60 153787.00 A7 456205.55 153817.81
J8 456310.71 153725.40 A8 456275.66 153756.20

9. All Seasons 8
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. M. Ecker, PE., “All Seasons Marina USACOE Permit Plan”, (2010).