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Home My WebLink About361Greatlsland_ShellfishSurvey_Compiled_20210330Shellfish Survey Sweetheart Creek West Yarmouth, Massachusetts 1 SHELLFISH SURVEY DESCRIPTION 1.0 INTRODUCTION On March 30, 2021, Hannah Raddatz and Paul Mancuso, Wetland Scientists of BSC Group (BSC) conducted a shellfish survey from the estimated spring hightide line into Land Under the Ocean of Sweetheart Creek in West Yarmouth, MA (the Site). The purpose of the survey was to evaluate shellfish habitat, shellfish species, and shellfish population density during a resource area evaluation of the shellfish habitat within the proposed project area of a minor modification to existing float and ramp within the Sweetheart Creek. This shellfish survey accompanies a Notice of Intent for 361 Great Island Road, West Yarmouth, MA. 2.0 SITE DESCRIPTION The portion of the Sweetheart Creek on which the project site is located roughly 775 feet from the Lewis Bay, which flows into this creek. The Sweetheart Creek is a tidal river that drains into Lewis Bay, beyond which lies Nantucket Sound. Abutting the property are several single-family homes, located along the shoreline, some with 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), FEMA Flood Zone AE (elevation 13) 3.0 SHELLFISH INVENTORY In order to evaluate existing shellfish habitat at the site, BSC conducted a shellfish survey from the estimated spring hightide line to below Mean Low Water (MLW). The weather during the survey was clear with temperatures in the mid 30’s. The survey commenced as the tide approached MLW and was completed as the tide began to rise above MLW toward Mean highwater (MHW). In order to sample for shellfish within the project area, 7 transects, located 10 feet apart, each with 6 plots, located 10 feet apart, (beginning from the edge of the 3-foot by 3- foot plot, resulting in a distance of roughly 13 feet), were conducted as follows: Transect 1 – Located 30 feet to the west of pier. Extending 65 feet seaward from estimated spring hightide line. Transect 2 – Located 20 feet to the west of pier. Extending 65 feet seaward from estimated spring hightide line. Transect 3 – Located 10 feet to the west of pier. Extending 65 feet seaward from estimated spring hightide line. Transect 4 – Located on the roughly center line of the existing pier. Extending 65 feet seaward from estimated spring hightide line. Transect 5 – Located 10 feet to the east of pier. Extending 65 feet seaward from estimated spring hightide line. Transect 6 – Located 20 feet to the east of pier. Extending 65 feet seaward from estimated spring hightide line. Shellfish Survey Sweetheart Creek West Yarmouth, Massachusetts 2 Transect 7 – Located 30 feet to the east of pier. Extending 65 feet seaward from estimated spring hightide line. Each transect, spaced 10 feet apart, with 6 plots each, spaced 10 feet apart starting at the edge of each 3-foot by 3-foot plot (resulting in an actual distance of 13 feet between plots), excavated to an area of approximately 3 feet by 3 feet by 1.5 feet deep. Typically, plots would extend at least 10 feet beyond the farthest float, ramp, or other structure associated with an existing or proposed pier/dock. However, beyond roughly 60 feet, the depths and sediment conditions along the sloping channel edge were too great for the safety of the shellfish surveyors. Plot 5 was taken landward of the existing piles and Plot 6 was taken seaward of the pilings, allowing for an assessment of the area where the existing piles will be relocated to. In all transects, Plots #1 - #3 were within salt marsh, therefore these areas were only visually inspected. Plots #4 - #6 were sampled between the intertidal beach and landward of the channel edge in water depths of roughly 1 foot to 3 feet. 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 361 Great Island Road. “T” stands for Transect and “P” stands for Plot, transects proceed from West to East. Shellfish Survey Sweetheart Creek West Yarmouth, Massachusetts 3 The table below identifies the shellfish discovered within the plots along the 7 Transects: Table 1 – Shellfish Inventory Plot – Description Shellfish Substrate and Other Observations Transect 1 – 30’ South of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None Peat under sand 52’ seaward None Sand 65’ seaward 1 Chowder Quahog, 1 Cherrystone Quahog Muck Transect 2 – 20’ South of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward 1 Chowder Quahog Sand 52’ seaward None Sand 65’ seaward 1 Littleneck, 1 Cherrystone Muck Transect 3 – 10’ South of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None Sand 52’ seaward 1 Littleneck Sand 65’ seaward 3 Chowder, Muck Transect 4 – Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None, close to Mussel Beds Sand 52’ seaward None Sand 65’ seaward 1 Chowder, 1 Littleneck Muck Transect 5 – 10’ North of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None Sand 52’ seaward 1 Chowder, 1 Littleneck Sand 65’ seaward 2 Chowder, 1 Cherrystone, 1 Littleneck Muck Transect 6 – 20’ North of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None Sand Shellfish Survey Sweetheart Creek West Yarmouth, Massachusetts 4 52’ seaward 1 Cherrystone Sand 65’ seaward 1 Chowder, 3 Cherrystone Muck Transect 7 – 30’ North of Centerline of Pier Spring High Tide Line None Salt Marsh 13’ seaward None Salt Marsh 26’ seaward Mussel Beds Salt Marsh 39’ seaward None Sand 52’ seaward None Sand 65’ seaward 1 Chowder Muck TOTAL NUMBER OF OBSERVATION PLOTS = 42 TOTAL NUMBER OF BAY SCALLOPS = 0 TOTAL NUMBER OF RIBBED MUSSELS = Mussel Beds in Salt Marsh TOTAL NUMBER OF OYSTERS = 0 TOTAL NUMBER OF QUAHOGS = 26 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) were noted in the Salt Marsh located adjacent to the Site, but no Ribbed Mussels were found within or adjacent to any sampling plots. Oyster and Softshell clams (Mya arenaria) shells were found within the intertidal area, but not living individuals were found in any plot. 4.0 TEMPORARY IMPACTS Proposed work related to the proposed minor modifications to the existing ramp and floats could have temporary minor impacts (turbidity) 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 only disturbance proposed is the relocation of two pilings.  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). It should be noted that shellfish were found under the existing pier/float system, documenting that the structure is not impacting shellfish.  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:  26 individual Quahogs (Mercenaria mercenaria) were found across all 42 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 extends to MHW. These areas contained dense populations of Ribbed Mussels, but no population of Ribbed Mussels were noted within excavated plots. Periwinkles (Littorina littorea) were noted in inundated/intertidal portions of the site. Photo 1: View of survey areas from the edge of the salt marsh. Looking northwest. Photo 2: View of survey areas from intertidal beach, excavated plots visible. Looking west. Site Photographs March 30, 2021 361 Great Island Road, West Yarmouth Shellfish Survey Page 1 Photo 3:View of Chowder and Cherrystone Quahogs found in one of the plots. Photo 3: View of Chowder Quahog found in one of the plots. Site Photographs March 30, 2021 361 Great Island Road, West Yarmouth Shellfish Survey Page 2