HomeMy WebLinkAbout21-004 Acheson Shellfish Report and PhotosShellfish Survey
170 Pleasant Street
South Yarmouth, Massachusetts
SHELLFISH SURVEY DESCRIPTION
1.0 INTRODUCTION
On April 5, 2021, Hannah Raddatz and Lindsey Carle, Wetland Scientists of BSC Group
(BSC) conducted a shellfish survey from MHW into Land Under the Ocean of Bass River in
South Yarmouth, MA (the Site). The purpose of the survey was to evaluate shellfish habitat,
shellfish species, and shellfish population density within the area of a proposed pier, ramp,
and floats within Bass River. This shellfish survey accompanies a Notice of Intent application
for 170 Pleasant Street, South Yarmouth, MA (the Site).
2.0 SITE DESCRIPTION
The portion of the Bass River on which the project site is located roughly .7 miles from the mouth
of the Bass River which flows into Nantucket Sound. Abutting the property are several single-
family homes, located along the shoreline, several with existing piers, ramps and floats. The
following resource areas are located onsite:
• Land Under the Ocean
• Land Containing Shellfish
• Salt Marsh
• Coastal Bank
• Land Subject to Coastal Storm Flowage (LSCSF)
• Riverfront Area (Bass River)
3.0 SHELLFISH INVENTORY
In order to evaluate existing shellfish habitat at the site, BSC conducted a shellfish survey from
the Mean Highwater (MHW) to below Mean Low Water (MLW). The weather during the survey
was overcast with temperatures in the mid 50's. The survey commenced as the tide approached
MLW and was completed as the tide began to rise above MLW toward MHW. In order to sample
for shellfish within the project area, 5 transects, located 8 feet apart (plus the distance between 4-
foot wide excavated plots, resulting in a 12 distance between transects), each with 7 plots,
located 10 feet apart (beginning from the edge of the 446ot by 446ot plot, resulting in a
distance of roughly 14 feet between plots), were conducted as follows:
Transect 1 —Located 12 (including the distance between 4-foot wide excavated plots, resulting in
a 12-foot distance between transects) feet to the north of proposed pier. Extending
approximately 84 feet seaward from MHW.
Transect 2 —Located roughly along the centerline of the proposed pier. Extending approximately
84 feet seaward fi•om MHW.
Transect 3 —Located 12 feet to the south of proposed pier. Extending approximately 84 feet
seaward from MHW.
Transect 4 —Located 24 feet to the south of proposed pier. Extending approximately 84 feet
seaward from MHW.
Transect 5 —Located 36 feet to the south of proposed pier. Extending approximately 84 feet
seaward from MHW.
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Shellfish Survey
170 Pleasant Street
South Yarmouth, Massachusetts
Typically, plots would extend at least 30 feet beyond the farthest float, ramp, or other structure
associated with an existing or proposed pier/dock. However, beyond roughly 85 feet, the depths
and sediment conditions (being mucky) were too great for the safety of the shellfish surveyors.
In all transects, Plots #1 and #2 were within salt marsh or areas of beach underlain with peat and
sparse salt marsh grasses, therefore these areas were only visually inspected. Plots #3 - #7 were
sampled between the intertidal beach and Land Under Ocean within the Bass River. Each plot
was excavated to sample for shellfish using either a standard Clam Rake, Quahog Rake, or visual
inspection (used only in areas of salt marsh or mussel beds). Each shellfish discovered in the plot
was counted then replaced back into the plot from which it came from.
Figure 1: Showing approximate location of Transects and Plots for this shellfish survey at 170
Pleasant Street. "T" stands for Transect and "P" stands for Plot, transects proceed from North to
South and Plots proceed from MHW into the Bass River. Note the lines depicted are not to scale
but for representation.
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Shellfish Survey
I70 Pleasant Street
South Yarmouth, Massachusetts
The table below identifies the shellfish discovered within the plots along the 5 Transect00
Table 1—Shellfish Inventory
Plot — Description
Shellfish
Substrate and Other
Observations
Transect 1-12' North of Proposed
Pier
MHW
Ribbed Mussel Beds, Sparse
Oysters
Salt Marsh
14'
seaward
of MHW
None
Sand
Underlain with
Peat
28'
seaward
of MHW
None
Silty Sand
42'
seaward
of MHW
None
Silty Sand
56'
seaward
of MHW
None
Silty Sand
70'
seaward
of MEW
1 Littleneck Quahog, 1
Chowder Quahog
Silty Sand
84'
seaward
of MEW
1 Cherrystone Quahog
Silty Sand
Transect 2 — Centerline of Proposed
Pier
MHW
Ribbed Mussel Beds, Sparse
Oysters
Salt Marsh
14'
seaward
of MHW
None
Sand
Underlain with
Peat
28'
seaward
of MHW
None
Silty Sand
42'
seaward
of MHW
None
Silty Sand
56'
seaward
of MEW
None
Silty Sand
70'
seaward
of MHW
1 Cherrystone Quahog, 1
Chowder Quahog
Silty Sand
84'
seaward
of MHW
1 Chowder Quahog
Silty Sand
Transect 3 —12' South of Proposed
Pier
MHW
Ribbed Mussel Beds, Sparse
Oysters
t
Salt Marsh
14'
seaward
of MHW
None
Sand
Underlain with
Peat
28'
seaward
of MHW
I Cherrystone Quahog, 1
Chowder Quahog
Silty Sand
42'
seaward
of MHW
None
Silty Sand
56'
seaward
of MHW
None
Silly Sand
70'
seaward
of MHW
1 Littleneck Quahog, 1
Cherrystone Quahog
Silty Sand
84'
seaward
of MHW
None
Silty Sand
Transect 4 — 24' South of Proposed
Pier
MHW
Ribbed Mussel Beds, Sparse
Oysters
Salt Marsh
14'
seaward
of MHW
None
Sand
Underlain with
Peat
28'
seaward
of MHW
3 Chowder Quahog, 1
Cherrystone Quahog, 1
Littleneck Quahog
Silty Sand
42'
seaward
of MHW
1 Scallop, 1 Littleneck
Quahog, 2 Chowder Quahog
Silty Sand
56'
seaward
of MHW
None
Silty Sand
70'
seaward
of MHW
1 Cherrystone Quahog, 1
Silty Sand
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Shellfish Survey
I70 Pleasant Street
South Yarmouth, Massachusetts
Chowder Quahog
84'
seaward
of MEW
None
Silty
Sand
Transeet 5 — 36' South of Proposed Pier
MHW
Ribbed Mussel Beds, Sparse
Oysters
Salt
Marsh
14'
seaward
of MEW
None
Sand Underlain with Peat
28'
seaward
of MEW
None
Silty
Sand
42'
seaward
of MHW
None
Silty
Sand
56'
seaward
of MHW
None
Silty
Sand
70'
seaward
of MHW
None
Silty
Sand
84'
seaward
of MEW
None
Si!
Sand
TOTAL NUMBER OF OBSERVATION PLOTS = 35
TOTAL NUMBER OF BAY SCALLOPS =1
RIBBED MUSSELS = Mussel Beds noted in Salt Marsh
TOTAL NUMBER OF OYSTERS = Sparse Oysters in Salt Marsh
TOTAL NUMBER OF QUAHOGS = 20
TOTAL NUMBER OF SOFT SHELL CLAMS = 0
TOTAL NUMBER OF RAZOR CLAMS= 0
It should also be noted that dozens of periwinkles (Littorina littorea) were documented within the
intertidal sampling areas. Clumps of Ribbed Mussels (Geukensia demissa) and sparse Oysters
were noted in the Salt Marsh located on Site. Oyster, Ribbed Mussel, and Softshell clams (Mya
arenaria) shells (deceased individuals) were found within the intertidal area.
4.0 TEMPORARY IMPACTS
Proposed work related to the proposed pier, ramp and floats could have minor impacts on the
intertidal area and Land Under the Ocean, but overall would have very limited impacts on
shellfish due to the low population density and through the observance of appropriate seasonal
timing.
■ The proposed work could occur during the fall/winter/early spring months when shellfish life
cycle activity is reduced. During the winter•, shellfish live at increased depths in the tidal
bottom with reduced metabolism. Therefore, only minimal impacts to shellfish habitat are
expected (pilings).
■ Pile driving work should occur from a barge at mid to high tide to prevent the barge from
running aground.
■ If necessary, existing shellfish could be dug and relocated from the site. However, based on
this shellfish survey this should not be necessary since a small population of shellfish were
located near the work area.
5.0 SUMMARY
BSC's shellfish survey identified the following:
■ 20 individual Quahogs (Mercenar•ia mercenaria) and one Scallop were found across all
35 plots. In addition, no spat or seeds were noted across the surveyed area.
■ The salt marsh located along the entire seaward edge of the Site and beyond MEW.
These areas contained dense populations of Ribbed Mussels and sparse populations of
Oysters. Periwinkles (Littorina littorea) were noted in inundated/intertidal portions of the
site.
rhoto 1: View of survey areas and property to the north (with existing pier) from the edge
of the salt marsh. Looking northeast.
Photo 2: View of survey area and property to the south (with existing pier) from the edge
of salt marsh. Looking southeast.
Site Photographs
April 5, 2021
1 / Pleasant Street, South Yarmouth
Shellfish Survey
Page 1
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r uvw �: v icw of �,nowaer ana Lnerrystone (luahogs found in one of the plots.
rnoto 4: view of (:ommon Cockle found in one of the plots.
Site Photographs
April 5, 2021
170 Pleasant Street, South Yarmouth
Shellfish Survey
Page 2
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