A shellfish study was conducted over two days in December 2011 to determine if the environmental conditions at Fish Finder Marine in Brigantine, NJ support shellfish populations in relation to a proposed marina expansion. A total of 24 sites were sampled using GPS and grab samples. One juvenile hard clam and 19 adult hard clams were found, indicating some viable habitat areas but densities below the threshold for designation as shellfish habitat. Water quality parameters were also measured and fell within normal ranges for the area. The study concluded that the shellfish densities did not substantiate the area as viable hard clam habitat for the proposed expansion.

1. A Shellfish Study for the Proposed Expansion of Fish Finder Marine
3645 Atlantic Brigantine Boulevard, Brigantine, New Jersey
December 8th & 9th 2011
Survey Conducted For:
Fish Finder Marine
Joe & Kim Fumo, Owner(s)
3645 Atlantic Brigantine Boulevard
Brigantine, New Jersey 08203
Survey Conducted By:
Richard Stockton College of New Jersey’s
Coastal Research Center
30 Wilson Avenue
Port Republic, NJ. 08241
(609) 652-4245
December 8th & 9th, 2011

2. Fish Finder 1
A Shellfish Study for the Proposed Expansion of Fish Finder Marine
3645 Atlantic Brigantine Boulevard, Brigantine, Atlantic County, New Jersey
December 8th & 9th, 2011
Introduction
A shellfish study was performed on December 8th & 9th 2011 to determine if Fish Finder
Marine’s environmental conditions support a viable shellfish population. 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 of Fish Finder Marine involves extending the existing (western) fixed pier to
a distance 260 feet from the existing bulkhead. The pier would extend in the south to north
direction and would have 5 finger piers spaced 20 feet apart. The proposed marina is bordered
on both sides by existing dock structures. The bay floor slopes from a depth at the bulkhead of -
0.5 feet out to a depth of -17.7 feet NGVD 27. The target species are those which fall under the
NJAC’s Coastal Zone Management Rules under Shellfish habitat. They include: Hard Clam
(Mercenaria mercenaria), Soft Clam (Mya arenaria), Easter Oyster (Crassostrea virginica), Bay
Scallops (Argopecten irradians), and Blue Mussels (Mytilus edulis), all of which are shellfish of
commercial and biological significance.
Methods and Materials
The study area was selected by analyzing the area of the proposed marina expansion and evenly
distributing the entire study area into uniform sub-sections (chart 1). The range of water depths
was from -0.5 to -17.7 feet below the National Geodetic Vertical Datum of 1927 shown in
Catalano’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 totaling 24 points (chart 1). These
points within the grid served as the locations for both the juvenile and adult shellfish survey.
Using the Leica RTK GPS system 1200, the positions of all the data points for both the juvenile
shellfish study and the adult shellfish study were obtained.
To conduct the juvenile shellfish study the 24 data point locations stored on the GPS system
were used as waypoints to locate each sample site (chart 1, table 3). 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 shellfish. 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 2).
To conduct the adult shellfish study, the site locations stored on the GPS were again used to
navigate to the pre-established locations (chart 1, table 3). At twelve locations 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

3. Fish Finder 2
until a 30’ transect distance was achieved. At all 24 locations a Wildco Ponar grab sample; with
an area of 0.75 sq. ft., was used to acquire samples. Replicate grabs were often necessary to
obtain a full sample size. 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 1 and 2).
Results
A total of 20 Hard Clams (Mercenaria mercenaria) were found in the study area. The size
frequency distribution of the clams found revealed that multiple year classes were present at the
site. This indicates that natural recruitment is taking place in the study area (table 1, chart 2).
Juvenile Shellfish
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. Twenty four sites were established and sampled
representing the area of the proposed marina expansion. One juvenile Hard Clam (Mercenaria
mercenaria) was found at location S4 resulting in a density 1.333 clams/sq. ft. at that location A
total of 18 sq. ft. was sampled producing an overall Hard Clam density of 0.055 clams/sq. ft.
across the total surface area. Only one juvenile Hard Clam was collected so the mean size was
1.2 cm with a range of 0 (table 1).
Adult Shellfish
As reported above the twelve sites were sampled using a 16” x 3” toothed bull rake and all 24
sites were sampled using a Wildco Ponar Grab Sample with an area of 0.75 sq.ft.. A total of 19
adult Hard Clams (Mercenaria mercenaria) were found in the entire area. Each raked site was
raked a distance of 30’. Clams were found in 11 of the 24 sites. Locations S5 (1.333 clams/sq.
ft.), S11 (4 clams/sq. ft.), and S23 (1.333 clams/sq. ft.), have densities which indicate viable
shellfish habitat. However, a total of 497.88 square feet was sampled with an overall density of
0.038 clams/sq. ft. across the entire area. The mean size of the clams collected was 6.37 cm with
an overall range of 4.6 from 4.3 to 8.9 cm (table 1).
Sedimentology
The sedimentology of the area consisted of fine sandy black mud, very fine sandy black mud,
fine muddy black/grey sand, fine muddy black sand, medium muddy black/grey sand, and black
mud (table 2).
Aquatic Vegetation
There were 2 major species of aquatic vegetation in the study area, Sea Lettuce (Ulva lactuca),
and Agardh’s Red Weed (Agardhiella tenera). At 8 locations Phragmites roots were found,
indicating that at one time a marsh existed here. The installation of the bulkhead likely resulted
in shoreline retreat as a result of scouring (table 2).
Other Shellfish
A total of, 3 Rock Crab (Cancer irroratus), 3 Mud Dog Whelk (Nassarius obsoletus), 2 juvenile
Blue Crab (Callinectes sapidus), and 1 adult Blue Crab (Callinectes sapidus), were found in the
process of locating shellfish (table 1).

4. Fish Finder 3
Conclusion
The study area at 3645 Atlantic Brigantine Boulevard, Brigantine, Atlantic County, NJ is the
location of the proposed expansion of Fish Finder Marine. The area was surveyed by utilizing
ArcGIS software, GPS equipment, grab sampling techniques, and a clam rake to help isolate
shellfish in accordance with the NJAC’s Coastal Zone Management Rules. It states that “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 shellfish study had
densities values (averaged across the total surface area) below the cited threshold. Hard Clam
(Mercenaria mercenaria) was the only relevant shellfish species found in the study area. There
were small areas which did support zones of viable habitat according to the cited density
threshold. Location S4 yielded 1.333 juvenile Hard Clams per square foot. Location S5 yielded
1.333 adult Hard Clams per square foot. Location S11 yielded 4 adult Hard Clams per square
foot. Location S23 yielded 1.333 Hard Clams per square foot. 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 (18.0 ft2) at 0.055 clams per square foot. The adults
recovered in the rake and ponar grab sample produced a value averaged across the total surface
area of 497.88 square feet yielded 0.038 clams per square foot. These numbers indicate that the
clam density within the area delineated for the installation of a marina expansion at Fish Finder
Marine does not substantiate a viable Hard Clam habitat.

5. Fish Finder 4
Water Quality Characteristics for Fish Finder Marine,
Brigantine, NJ.
Site of the Proposed Marina Expansion
Temperature, Salinity, Dissolved Oxygen, Depth, pH, Specific Conductivity, and
Turbidity Data for Shellfish Habitat
Introduction:
The Richard Stockton Coastal Research Center (CRC) completed a juvenile and adult hard clam
study for the proposed development of Fish Finder Marine, Brigantine, NJ in December 2011.
Twenty four sites were survey for juvenile and adult hard clams. In this study, one juvenile clams
was observed and 19 adult clams were obtained within 497.88 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 December 8th & 9th 2011 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 average temperature of 10.92 degrees Celsius 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 of 28.0 ppt 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 9.66 mg/L, and 105.80% respectively. The pH value of 7.91 is
within the normal range for all stages of Hard Clam development. None of the remaining water
quality parameters including depth, specific conductivity (44.32 mS/cm), and turbidity (9.30
NTU), would dictate that shellfish could not live in the waters of the proposed development of
Fish Finder Marine (see appendix at end).

6. Fish Finder 5

7. Fish Finder 6
Chart 2: Length Frequency for Hard Clams Collected During Site
Inspection at Fish Finder Marine, Brigantine, NJ. December 8th & 9th
8
7
6
5
Frequency 4
3
2
1
0
0-25 25-38 38 51 51-63 63-76 76-102
Data Bin Ranges (mm)

8. Fish Finder 7
Table 1: Sample Sites Used to Determine the Density of Adult and Juvenile Hard Clams
Transect Juvenile Clams (live) Adult Clams (live) Clams Per Site Other Shellfish Observations Transect Length Grab Sample Area Juvenile Hard Clam Density Adult Hard Clam Density Mean Range
S1 - 1 Hard Clam: 8.4 cm 1 - Rocks 30' 0.75' - 0.024 8.4 0
1 Adult Hard Clam
S2 - 1 Hard Clam: 5.5 cm 1 - 30' 0.75' - 0.024 5.5 0
Shell
2 Hard Clam: 7.2 cm, 7.4 2 Adult Hard Clam
S3 - 2 - 30' 0.75' - 0.05 7.3 0.2
cm Shells, Rocks
S4 1 Hard Clam: 1.2 cm - 1 - - - 0.75' 1.333 - 1.2 0
Razor Clam Shell,
S5 - 1 Hard Clam: 4.8 cm 1 - - 0.75' - 1.333 4.8 0
Gravel in substrate
1 Blue Crab
Blue Mussel Shells,
S6 - - 0 (Callinectes sapidus ): - 0.75' - - - -
Hard Clam Shells
4.2 cm
1 Adult Hard Clam
S7 - 1 Hard Clam: 7.1 cm 1 - Shell, 1 Adult Razor 30' 0.75' - 0.024 7.1 0
Clam Shell
2 Rock Crabs (Cancer Rocks, Hard Clam
3 Hard Clam: 4.6 cm, 4.3
S8 - 3 irroratus ): 3.7 cm, 4.1 shells, Tube worm 30' 0.75' - 0.073 4.6 0.8
cm, 5.1 cm
cm casings, Oyster shells
5 Hard Clam: 5.7 cm, 6.3
5.7 - cm, 8.3 cm, 8.0 cm, 5.7 5 - - 30' 0.75' - 0.123 6.8 2.6
cm
1 Mud Dog Whelk Blue Mussel Shells,
S10 - - 0 - 0.75' - - - -
(Nassarius obsoletus) Jingle Clam Shells
3 Hard Clam: 7.4 cm, 4.4 1 Rock Crab (Cancer
S11 - 3 Tube worm casings - 0.75' - 4 5.86 3
cm, 5.8 cm irroratus): 3.5 cm
1 Juvenile Blue Crab
(Callinectes sapidus): 2.6 Significant amount of
S12 - - 0 - 0.75' - - - -
cm, 2 Mud Dog Whelk Tube worm casings,
(Nassarius obsoletus)
S13 - - 0 - - 30' 0.75' - - - -
Tube worm, Juvenile
S14 - - 0 - 30' 0.75' - - - -
Hard Clam Shells
Blue mussel Shells,
S15 - 1 Hard Clam: 6.2 cm 1 - tube worm casings, 30' 0.75' - 0.024 6.2 0
rocks
1 Tube Worm, Tube
S16 - - 0 - Worm Casings, Snail - 0.75' - - - -
shells
24 Tube Worms,
S17 - - 0 - Crushed Blue Mussel - 0.75' - - - -
Shells
Crushed Blue Mussel
S18 - - 0 - Shells, Snail Shells, - 0.75' - - - -
Tube Worm Casings
S19 - - 0 - - 30' 0.75' - - - -
S20 - - 0 - - 30' 0.75' - - - -
S21 - - 0 - 36 Blue mussel shells 30' 0.75' - - - -
24 juvenile clam
1 Blue Crab (Callinectes shells, Hard Clam
S22 - - 0 - 0.75' - - - -
sapidus): 2.9 cm Shells, Blue Mussel
Shells
Crushed Blue Mussel
S23 - 1 Hard Clam: 8.9 cm 1 - Shells, 12 Juvenile - 0.75' - 1.333 8.9 0
Hard Clam Shells
Clam Shells, Crushed
S24 - - 0 - Blue Mussel Shells, 1 - 0.75' - - - -
Tape Worm
Adult Shellfish Study: 497.88 sq. ft. sampled, 19 adult Hard Clams = 0.038 clams/sq. ft.; Juvenile Shellfish Study: 18 sq. ft. sampled, 1 Juvenile Hard Clams = 0.055 clams/ sq. ft.

9. Fish Finder 8
Table 2: Aquatic Vegetation & Sediment Type
Site # Species & viability of aquatic vegetation Sediment
Agardh's Red Weed (Agardhiella tenera), and Minimal amounts of Sea
S1 Fine Muddy Sand, Black/Grey
Lettuce (Ulva lactua)
Minimal amounts of Sea Lettuce (Ulva lactua ), and Agardh's Red
S2 Fine Muddy Sand, Black
Weed (Agardhiella tenera )
Agardh's Red Weed (Agardhiella tenera) , and Sea Lettuce (Ulva
S3 Medium Muddy Sand, Black/Grey
lactua)
S4 Phragmities Roots Fine Sandy Mud, Black
S5 Phragmities Roots Fine Sandy Mud, Black
S6 Phragmities Roots Fine Sandy Mud, Black
S7 Ahardh's Red Weed (Agardhiella tenera) , and Phragmities Roots Medium Muddy Sand, Black/Grey
S8 Phragmities Roots Very Fine Sandy Mud, Black
S9 Sea Lettuce (Ulva lactua) , and Phragmities Roots Very Fine Sandy Mud, Black
S10 Phragmities Roots Very Fine Sandy Mud, Black
S11 Sea Lettuce (Ulva lactua) Very Fine Sandy Mud, Black
S12 no vegitation found Very Fine Sandy Mud, Black
S13 no vegitation found Mud, Black
Sea Lettuce (Ulva lactua), and Minimal amounts of Agardh's Red Weed
S14 Very Fine Sand Mud, Black
(Agardhiella tenera)
S15 Sea Lettuce (Ulva lactua) Very Fine Sand Mud, Black
S16 no vegitation found Very Fine Sandy Mud, Black
S17 no vegitation found Very Fine Sandy Mud, Black
S18 Phragmities Roots Very Fine Sandy Mud, Black
S19 Minimal amounts of Sea Lettuce (Ulva lactua ) Very Fine Sand Mud, Black
S20 no vegitation found Very Fine Sand Mud, Black
S21 no vegitation found Mud, Black
S22 no vegitation found Very Fine Sandy Mud, Black
S23 no vegitation found Very Fine Sandy Mud, Black
S24 no vegitation found Fine Sandy Mud, Black

10. Fish Finder 9
Table 3: Fish Finder Marine Shellfish Study
December 8th & 9th Survey Points
Transect Easting Northing
S1 522756.72 204668.65
S2 522731.79 204667.87
S3 522706.71 204667.10
S4 522756.20 204683.68
S5 522731.22 204682.92
S6 522706.17 204682.07
S7 522755.80 204698.64
S8 522730.74 204697.95
S9 522705.79 204697.06
S10 522755.25 204713.77
S11 522730.26 204712.78
S12 522705.27 204712.09
S13 522754.72 204728.62
S14 522729.79 204727.72
S15 522704.86 204727.05
S16 522754.30 204743.53
S17 522729.30 204742.92
S18 522704.30 204742.04
S19 522753.88 204758.60
S20 522728.83 204757.86
S21 522703.78 204757.03
S22 522753.36 204773.60
S23 522728.38 204772.81
S24 522703.36 204772.10

11. Fish Finder 10
Table 4: Fish Finder Marine Shellfish Study Water Quality Data
Specific
Temperature Salinity Dissolved Oxygen Dissolved Oxygen Depth Conductivity
Site (Celsius) (ppt) (as a %) (mg/L) (feet) pH (mS/cm) Turbidity (NTU)
S1 10.89 27.41 111.1 10.07 0.638 7.90 44.21 9.30
S2 11.34 27.55 112.6 10.17 1.490 7.90 44.51 8.90
S3 11.23 27.64 121.5 10.80 1.150 7.86 44.48 8.76
S4 11.24 27.54 102.9 9.45 0.951 7.93 44.05 9.60
S5 11.40 27.55 102.8 9.40 1.468 7.92 44.49 9.55
S6 11.36 27.53 101.0 9.17 1.167 7.93 44.12 9.90
S7 10.80 28.81 103.8 9.32 2.760 7.94 44.74 8.60
S8 10.89 28.77 111.0 10.14 2.993 7.92 44.66 9.20
S9 10.79 28.74 114.6 10.40 3.842 7.75 44.62 9.00
S10 10.83 28.57 116.0 10.20 3.813 7.93 44.45 9.80
S11 10.77 28.43 97.5 9.08 3.150 7.93 44.31 8.80
S12 10.69 28.71 109.8 9.95 4.569 7.88 44.60 10.10
S13 10.81 28.46 107.3 9.74 2.701 7.95 44.25 8.20
S14 10.76 28.49 104.7 9.51 5.844 7.95 44.33 9.20
S15 10.64 28.42 105.1 9.63 3.841 7.94 44.27 8.50
S16 10.61 28.28 102.6 9.45 6.261 7.93 44.00 9.10
S17 10.56 28.17 102.3 9.42 6.449 7.95 43.89 9.70
S18 10.54 28.1 101.5 9.4 2.874 7.94 43.76 10.50
S19 11.08 27.41 90.7 8.90 7.801 7.92 44.18 9.10
S20 11.07 27.45 102.8 9.41 6.070 7.92 44.78 8.80
S21 11.19 27.45 106.4 9.56 2.680 7.92 44.09 9.30
S22 10.84 27.49 99.9 9.25 14.800 7.91 44.65 10.10
S23 10.93 27.48 109.7 9.97 15.230 7.90 44.23 9.80
S24 10.85 27.52 101.7 9.39 8.760 7.91 44.10 9.50
Avg 10.92 28.00 105.80 9.66 4.64 7.91 44.32 9.30

12. Fish Finder 11
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. J. Catalano. PE., “Fish Finder Marine USACOE Permit Application Plan”, (2011).

13. Fish Finder 12
APPENDIX OF LITERATURE FOUND DISCUSSING HARD
CLAM HABITAT PARAMETERS
The References Below Cover Specific Parameters for Mercenaria mercenaria clams
Hill, K. (2004). Smithsonian Marine Station at Fort Pierce. Retrieved January
13, 2012, from http://www.sms.si.edu/irlspec/mercen_mercen.htm
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.”
Mann, R., Harding, J. M., Southworth, M. J., Wesson, J. A. (2005). Northern
Quahog (hard clam) Mercenaria mercenaria abundance and habitat use
in Chesepeake Bay. Journal of Shellfisheries Research, 24(2), 509-516.
“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.”
Mulholland, R. (1984). Habitat Suitability Index Models: Hard Clam. Florida
Cooperative Fish and Wildlife Research Unit. FWS/OBS-82/10.77
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

14. Fish Finder 13
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
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

15. Fish Finder 14
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”. ”