HomeMy WebLinkAboutSEPA Att E Habitat Mgmt Plan & No Net Loss Rpt 2020
146 N Canal St, Suite 111 • Seattle, WA 98103 • www.confenv.com
Smersh Farm Habitat Management Plan and
No Net Loss Report FINAL REPORT
Prepared for:
BDN, LLC
October 2019, Revised September 2020
May 07 2021
146 N Canal St, Suite 111 • Seattle, WA 98103 • www.confenv.com
Smersh Farm Habitat Management Plan and
No Net Loss Report FINAL REPORT
Prepared for:
BDN, LLC
Attn: Brad Nelson
Prepared by:
Grant Novak
Confluence Environmental Company
October 2019, Revised September 2020
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TABLE OF CONTENTS
1.0 INTRODUCTION .............................................................................................................................................. 1
2.0 PROJECT DESCRIPTION ............................................................................................................................... 1
2.1 Planting and Grow-Out .................................................................................................................................... 3
2.2 Maintenance .................................................................................................................................................... 4
2.2.1 Site Inspection ........................................................................................................................................ 4
2.2.2 Tube Removal......................................................................................................................................... 4
2.3 Harvesting ........................................................................................................................................................ 5
2.4 Habitat Management Plan ............................................................................................................................... 6
2.4.1 Maintenance, Repair, and Operation ...................................................................................................... 6
2.4.2 Species-Specific Activities ...................................................................................................................... 7
2.4.3 Farm Plan Record-Keeping Log ............................................................................................................. 8
3.0 EFFECTS ANALYSIS ...................................................................................................................................... 8
3.1 Noise................................................................................................................................................................ 9
3.1.1 Existing Conditions ................................................................................................................................. 9
3.1.1.1 Airborne Noise ........................................................................................................................................ 9
3.1.1.2 Underwater Noise ................................................................................................................................... 9
3.1.2 Effects of Noise ..................................................................................................................................... 10
3.1.2.1 Effects of Airborne Noise ...................................................................................................................... 10
3.1.2.2 Effects of Underwater Noise ................................................................................................................. 11
3.1.3 Summary of Noise Effects .................................................................................................................... 12
3.2 Water Quality ................................................................................................................................................. 13
3.2.1 Existing Conditions ............................................................................................................................... 13
3.2.2 Effects to Water Quality ........................................................................................................................ 13
3.2.3 Filtration Effects .................................................................................................................................... 13
3.2.4 Harvest Effects...................................................................................................................................... 15
3.2.5 Summary of Effects to Water Quality .................................................................................................... 16
3.3 Sediment Quality ........................................................................................................................................... 17
3.3.1 Existing Sediment Conditions ............................................................................................................... 17
3.3.2 Effects to Sediment Quality ................................................................................................................... 17
3.4 Sediment Transport and Bathymetry ............................................................................................................. 18
3.4.1 Existing Conditions ............................................................................................................................... 18
3.4.2 Effects to Sediment Transport and Bathymetry .................................................................................... 18
3.4.3 Addition of Gear .................................................................................................................................... 18
3.4.4 Harvest Activities .................................................................................................................................. 19
3.4.5 Summary of Effects to Sediment Tranport and Bathymetry .................................................................. 19
3.5 Migration, Access, and Refugia ..................................................................................................................... 19
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3.5.1 Existing Conditions ............................................................................................................................... 20
3.5.2 Effects to Migration, Access, and Refugia ............................................................................................ 20
3.6 Forage Fish .................................................................................................................................................... 21
3.6.1 Existing Conditions ............................................................................................................................... 21
3.6.2 Effects to Forage Fish ........................................................................................................................... 21
3.6.3 Spawning Habitat Overlap .................................................................................................................... 21
3.6.4 Sediment Mobilization ........................................................................................................................... 22
3.6.5 Summary of Effects to Forage Fish ...................................................................................................... 22
3.7 Benthic Infauna and Epifauna ........................................................................................................................ 22
3.7.1 Existing Conditions ............................................................................................................................... 22
3.7.2 Effects to Benthic Infauna and Epifauna ............................................................................................... 22
3.7.3 Culture Tube Placement Effects ........................................................................................................... 22
3.7.4 Harvest Effects...................................................................................................................................... 23
3.7.5 Summary of Effects to Benthic Infauna and Epifauna ........................................................................... 24
3.8 Waterfowl ....................................................................................................................................................... 24
3.8.1 Existing Conditions ............................................................................................................................... 24
3.8.2 Summary of Effects to Waterfowl .......................................................................................................... 24
3.9 Aquatic Vegetation ......................................................................................................................................... 26
3.9.1 Existing Conditions ............................................................................................................................... 26
3.9.2 Effects to Aquatic Vegetation ................................................................................................................ 27
3.10 Plastics and toxicity ....................................................................................................................................... 27
3.10.1 Existing Conditions ............................................................................................................................... 27
3.10.2 Summary of Effects from Plastics and Toxicity ..................................................................................... 27
3.11 Summary of Potential Effects......................................................................................................................... 28
4.0 REFERENCES ............................................................................................................................................... 31
TABLES
Table 1. Underwater Noise Thresholds by Functional Hearing Group ......................................................................... 11
Table 2. Clearance Rate Calculations for Pacific Oyster, Manila Clam, and Geoduck ................................................ 14
Table 3. Summary of Potential Effects from Geoduck Aquaculture ............................................................................. 29
FIGURES
Figure 1. Smersh Parcel and Vicinity ............................................................................................................................. 1
Figure 2. Proposed Geoduck Planting Area and Distances from High Water ................................................................ 2
Figure 3 Marine Birds Foraging in Shellfish Beds ........................................................................................................ 25
Figure 4 Scoters Foraging on Mussels Encrusting Geoduck Culture Tubes ................................................................ 26
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1.0 INTRODUCTION
BDN, Inc., (BDN) has leased parcel 721031007 (Smersh parcel) on Shine Road, in Squamish Harbor,
west of the Hood Canal Bridge and is proposing to operate a geoduck farm at the site (Figure 1). A
conditional use permit is required by Jefferson County and, as part of the permit application, a
habitat management plan and no net loss report are required (JCC 18.25.440).
The standard of “No Net Loss” of ecological functions was established by Washington State in the
Shoreline Management Act of 1971 and is implemented through a framework outlined in Jefferson
County’s Shoreline Master Program. This document presents an assessment of the proposed
aquaculture activities and demonstrates how geoduck aquaculture at the Smersh parcel will be
managed to achieve no net loss of ecological functions.
2.0 PROJECT DESCRIPTION
The project, if approved with current design, will consist of the following elements as described
below. Potential impacts described herein are based on this current design.
BDN proposes to plant up to 5.15 acres of geoducks at the site between +2 feet and approximately -2
feet relative to mean lower low water (MLLW) (Figure 2). The lower boundary of planting has been
Figure 1. Smersh Parcel and Vicinity
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determined based on the location of the eelgrass bed below approximately -2 feet MLLW
(Confluence 2016, Confluence 2018).
To protect geoduck seed from predators, PVC tubes 4” in diameter by 10” long would be placed
into the sandy substrate at low tide, while the tidelands are exposed, before any geoduck seed is
planted. Tubes would be placed at an approximate density of 1 tube per square foot with 3” to 5”
of the tube exposed above the substrate. A low pressure water hose may be used to loosen the
substrate sufficiently to properly insert the PVCtubes. Tubes will be labeled with contact
information for BDN. 12-25 workers will work to insert these tubes during each approximately 5-
hour shift. This will allow for approximately 6,000-10,000 tubes to be placed per day.
Geoduck seed will then be obtained from a certified hatchery and planted in the installed PVC
tubes when 4-5 mm in size. The juvenile geoducks will be placed in the installed PVC tubes by
divers during times when the tubes are submerged. No water jets will be used during placement
of the seed in the PVC tubes. The tubes will be clipped shut at the top by the divers, using plastic
clips, after the seed has been planted. Planting will begin in spring and continue through fall.
Planting activities will occur once per year, typically in June or July, over a period of 20-25 days.
No netting will be installed over the tubes, and no rebar or other materials will be used in
connection with the planting, maintenance or harvest activities. No fill materials or other
nursery/grow-out structures will be installed on the site.
Figure 2. Proposed Geoduck Planting Area and Distances from High Water
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2.1 Planting and Grow-Out
Locations for geoduck clam aquaculture do not typically require much, if any, site preparation prior
to planting because they are located in sandflats or mudflats that do not have large substrate
materials. Substrate composition in the proposed culture area is primarily sand.
There will be no removal of native materials from the site during site preparation. Excessive
amounts of macroalgae (i.e., Ulva) will be hand-raked away from the planting area but left on-site.
Successive tides will redistribute algae across the site. Non-native dwarf eelgrass (Zostera japonica),
which is very sparsely distributed throughout the proposed planting area (Confluence 2016,
Confluence 2018), will not be removed during planting. Native eelgrass (Zostera marina) will not be
disturbed and all geoduck planting will occur outside of the 16-foot buffer from eelgrass bed as
delineated by Confluence Environmental Company (Confluence) in July 2016 and reverified in
2017. Site preparation, if any, would occur at the same time as culture tube installation.
Geoduck seed are highly vulnerable to predation because of their small size and the shallow depth
at which they reside in the substrate when small. There will be no active predator removal from the
site. Predator control would be achieved through exclusion by planting geoduck seed into plastic
PVC culture tubes. Two years after planting, when the geoducks have reached a depth sufficient to
avoid predators, beach workers will remove the tubes by hand at low tide. Consistent with Corps
requirements, if any herring spawn is found on the PVC tubes, they will not be removed until the
eggs have hatched. The PVC tubes will be placed in large bags and removed for reuse or proper
upland disposal.
Usually, harvesting will begin between five and six years after planting; the exact timing of
harvesting will depend on a variety of environmental and economic factors. The total harvest
window is expected to be 1-2 years. The majority of harvesting will be conducted at high tides by
divers using surface-supplied air. A small amount of beach harvesting will be conducted during the
"cleanup" harvest phase at the end of the harvesting period when there are fewer geoducks
remaining on the beach. Both dive harvests and beach harvests use the same extraction equipment.
A diesel or gasoline engine located on the work skiff is used to power a water jet nozzle that
loosens the substrate around each geoduck. The engine will have a muffler to minimize noise
impacts. The water intake hose will include a 2.36 mm wire mesh screen covering the intake to
prevent fish entrainment in the low-pressure pump. The water jet nozzle is at the end of an
approximately 150' long, 1.5" delivery hose. The nozzle is approximately 27" long and may supply
up to 20-30 gallons of water per minute at 40 psi.
After geoducks are removed from the substrate as described above, they will be stored in crates
located on the work skiff prior to transport off-site. During both dive and beach harvesting, the
work skiff will not be anchored in any native eelgrass beds. Dive harvests will be conducted during
daylight hours. Divers work within a 150' radius of the work skiff at depths of 5' to 20' using surface
supplied air. The vessel engine will be turned off while divers are working for diver safety. When
beach harvesting, the skiff is regularly moved so that it always remains near the water's edge.
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Water hoses are then run from the skiff to the beach. Dive harvests will employ 1 diver and 2
support workers in the skiff. Dive harvesting will usually last for 3-to 6 hours each harvest day.
Beach harvests will employ 2 workers on the beach and 2 support workers on the skiff.
Harvesting activities at this location will occur only during daylight hours, over a period of about 5
hours per day, averaging 3-4 harvest days per week during the one to two year harvest period.
BDN will comply with Corps' conditions associated with herring, surf smelt, and sand lance
spawning.
Site inspections will be made weekly, or more frequently if needed due to adverse weather or
citizen complaints, to ensure that PVC tubes have not become dislodged by storm activity. Site
inspections will be generally conducted by 2-4 BDN employees walking the tidelands and
surrounding areas at low tide. Site maintenance will also include monitoring and relocation of
built-up drift macroalgae (e.g. Ulva). If low tide periods occur at night, these workers may use
individual LED headlamps for such inspection and maintenance work. If any maintenance work is
required, this will be performed by as many as four people but should typically require no more
than 1 hour for each such maintenance event. No vessel operations will take place at night.
2.2 Maintenance
2.2.1 Site Inspection
Regular site inspections will be made during low tides to ensure that PVC tubes have not become
dislodged and drifted onto the beach. All unnatural debris will be removed from the beach to
prevent it from entering the water. These regular inspections will continue until all tubes have been
removed from the beach. Inspections will typically be made with 2 to 4 workers and staged from
the 24-foot work skiff. Inspections will include monitoring for build-up of drift macroalgae. Ulva
can unexpectedly inundate a given farm, covering tubes entirely and choking out all sea-life below,
including juvenile geoduck clams. Drift algae is typically heaviest in late spring to mid-summer
months. If a given farm area becomes heavily infested with the drift algae, the algae can be picked
up and moved to the top of the farm area where it can be distributed on the upper beach portion
that is not used for farming.
2.2.2 Tube Removal
The tubes will be removed when the geoducks have reached a depth sufficient to avoid predators.
The depth to which the geoducks can burrow is typically substrate driven, and they tend to burrow
more quickly in sandy substrates versus those substrates containing a mixture of shell or gravel. In
sandier substrates, the geoducks may burrow to the desired protective depth of 18 to 24 inches in 18
months, whereas in substrates with more gravel, it may take as much as 24 months to accomplish
this. In either case, tube removal should be completed within 24 months of planting.
All gear installed on a particular beach must be removed during the lowest tides of the year. When
a particular beach is ready for gear removal, workers will come to the beach by boat and remove all
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PVC tubes by hand. Consistent with Corps requirements, prior to removal, PVC tubes will be
inspected for herring spawn. If any herring spawn is found, no tubes will be removed until eggs
have hatched. Workers will remove the PVC tubes by hand and place them in large bags that will
be stored on the work boat until all the gear is removed from the site for reuse or proper upland
disposal at an approved disposal site.
Tube removal will be done from winter to early summer to avoid Ulva buildup, as the weight of
accumulated Ulva can add thousands of pounds to aquaculture equipment. A crew of 10 workers
will be used to remove approximately 5,000 tubes per day.
2.3 Harvesting
Typically, harvesting will begin between five and six years after planting; the exact timing of
harvesting will depend on a variety of environmental and economic factors. The total harvest
window is expected to be 1-2 years. The majority of harvesting will be conducted at high tides by
divers using surface-supplied air. A small amount of beach harvesting will be conducted during the
"cleanup" harvest phase at the end of the harvesting period when there are fewer geoducks
remaining on the beach. Both dive harvests and beach harvests use the same extraction equipment.
A diesel or gasoline engine located on the work skiff is used to power a water jet nozzle that
loosens the substrate around each geoduck. The engine will have a muffler to minimize noise
impacts. The water intake would be fitted with screens that meet National Marine Fisheries Service
(NMFS) screening criteria to prevent fish entrainment in the low-pressure pump. The water jet
nozzle is at the end of an approximately 150' long, 1.5" delivery hose. The nozzle is approximately
27" long and may supply up to 20-30 gallons of water per minute at 40 psi.
Harvesting would be accomplished by 2- to 4-person teams. After geoducks are removed from the
substrate as described above, they will be stored in crates located on the work skiff prior to
transport off-site. During both dive and beach harvesting, the work skiff will not be anchored in
any native eelgrass beds. Dive harvests will be conducted during daylight hours. Divers work
within a 150' radius of the work skiff at depths of 5' to 20' using surface supplied air. The vessel
engine will be turned off while divers are working for diver safety. When beach harvesting, the
skiff is regularly moved so that it always remains near the water's edge. Water hoses are then run
from the skiff to the beach. Dive harvests will typically employ 1 diver and 2 support workers in
the skiff. Dive harvesting will usually last for 3-to 6 hours each harvest day. Beach harvests will
employ 2 workers on the beach and 2 support workers on the skiff.
Harvesting activities at this location will occur only during daylight hours, over a period of about 5
hours per day, averaging 3-4 harvest days per week during the one to two year harvest period.
BDN will comply with Corps' conditions associated with herring, surf smelt, and sand lance
spawning.
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2.4 Habitat Management Plan
Avoidance, conservation, and minimization measures that would be adopted at the proposed
geoduck farm are consistent with those outlined in relevant shellfish culture conservation measures
adopted by the U.S. Army Corps of Engineers (Corps) in their programmatic consultation with the
NMFS (2016a) and USFWS (2016) on Nationwide Permit 48 for shellfish farming in the State of
Washington. Avoidance of potential effects, where possible, is the priority. The avoidance,
conservation, and minimization measures at the proposed geoduck farm include the following and
are described in more detail in Sections 2.4.1, 2.4.2, and 2.4.3:
Maintenance, Repair, and Work
Species-Specific Activities
Farm Plan Record-Keeping Log
2.4.1 Maintenance, Repair, and Operation
1. Damage to aquatic vegetation and substrates from boats or barges will be avoided through
the following practices:
Boats and barges shall be moored and operated in deeper water and away from
aquatic vegetation to prevent potential impacts from propeller scour or anchors.
If boats need to come into the project area for personnel or gear access, then vessels
shall not ground in native eelgrass or attached kelp beds.
Groundings will be minimal and temporary and only occur in areas of blank sand
where a boat’s grounding will have no effect on fish and wildlife conservation areas
or intertidal habitat. Vessels would have approximately 20 square feet of ground
contact for up to 6 hours per day during approximately 10 low tide workdays per
year.
Measures shall be implemented to prevent anchors, chains, and ropes from dragging
on the bottom. No vessels will be anchored over native eelgrass beds.
Intertidal areas shall not be used to store materials such as tools, bags, marker stakes,
or PVC tubes. Materials that are not in use or immediately needed shall be removed
to an off-site storage area and the site kept clean of litter.
All excess or unsecured materials and trash shall be removed from the beach prior to
the next incoming tide.
Moving large substrate materials (e.g., logs, rocks) during aquaculture operations
shall be avoided to the extent feasible. Where the relocation of such features is
necessary, they shall be relocated no farther than another section of the nearby beach.
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There shall be no modification of substrate in an effort to improve conditions for
geoduck clam aquaculture.
2. Operators of vehicles or machinery will reduce contamination from vehicles and equipment
through the following practices:
Pump intakes (e.g., geoduck harvest) that use seawater shall be screened in
accordance with NMFS and Washington Department of Fish and Wildlife (WDFW)
criteria to protect fish life.
Unsuitable material (e.g., trash, debris, asphalt, or tires) shall not be discharged or
used as fill (e.g., create berms, or provide nurseries).
All vessels operated within 150 feet of any stream, waterbody, or wetland shall be
inspected daily for fluid leaks before leaving the staging area. Repair any leaks
detected in the staging area before resuming operation.
3. At least once a month and directly following storm events, beaches in the project vicinity
shall be patrolled by crews who will retrieve aquaculture debris (e.g., PVC tubes) that
escape from the project area. Within the project vicinity, locations shall be identified where
debris tends to accumulate due to wave, current, or wind action, and after weather events
these locations shall be patrolled by crews who will remove and dispose of debris
appropriately.
4. The grower shall not use tidelands waterward from the line of mean higher high water
(MHHW) for the storage of aquaculture gear. All aquaculture gear shall be stored and
sorted at an upland facility and transported to the project area at the time of deployment.
5. The grower shall ensure that PVC culture tubes are secured in the substrate to prevent them
from escaping from the project area.
6. Employees shall be trained in meeting environmental objectives.
2.4.2 Species-Specific Activities
1. A Pacific herring spawn survey shall be conducted prior to undertaking the activities listed
below if any of these activities occur outside the Tidal Reference Area 13 in-water work
window, which is April 15 through January 14 (Washington Administrative Code [WAC]
220-110-271). Activities requiring a spawn survey include: (1) PVC culture tube placement,
(2) geoduck harvesting, and (4) culture tube removal. Vegetation, substrate, and aquaculture
equipment (e.g., P tubes) shall be inspected for Pacific herring spawn. If herring spawn is
present, these activities are prohibited in the areas where spawning has occurred until the
eggs have hatched and spawn is no longer present (typically 2 weeks). Records shall be
maintained, including the date and time of surveys; the area, materials, and equipment
surveyed; results from the survey; etc. The record of Pacific herring spawn surveys shall be
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made available to the Corps, NMFS, and U.S. Fish and Wildlife Service (USFWS), upon
request.
2. Shellfish culturing shall not be placed above the tidal elevation of +7 feet MLLW if the area
is documented as surf smelt spawning habitat by WDFW (note the project will be confined
below +2 feet MLLW).
3. Shellfish culturing shall not be placed above the tidal elevation of +5 feet MLLW if the area
is documented as Pacific sand lance spawning habitat by WDFW (note the project will be
confined below +2 ft MLLW).
2.4.3 Farm Plan Record-Keeping Log
Logs will be kept to record the timing, personnel, and findings of the following surveys and/or
cleanup activities.
1. Pacific herring spawn surveys: The grower shall maintain a record with the following
information and the record shall be made available upon request to the Corps, NMFS, and
USFWS: date of survey, location of area patrolled, surveyor name, and whether herring
spawn was observed in the project area.
2. Spills or cleanups conducted on the beach: The grower shall maintain a record with the
following information and the record shall be made available upon request to the Corps,
NMFS, and USFWS: date of patrol, location of areas patrolled, description of the type and
amount of retrieved debris, and other pertinent information.
3.0 EFFECTS ANALYSIS
The “no net loss” standard contained in WAC 173-26-186 requires that the impacts of shoreline use
and/or development (e.g., geoduck aquaculture) be identified and mitigated such that there are no
resulting adverse impacts to ecological functions or processes. The Washington State Department of
Ecology (Ecology) defines no net loss as meaning that no significant adverse impacts to preexisting
ecological function shall occur as a result of proposed shoreline development. Jefferson County
further defines no net loss as “the maintenance of the aggregate total of the county shoreline
ecological functions over time.” Ecological function is defined by the County as “the work
performed or role played by the physical, chemical, and biological processes that contribute to the
maintenance of the aquatic and terrestrial environments that constitute the shoreline’s natural
ecosystem” (JCC 18.25.100(5)(a)).
In the following analysis, habitat and species indicators serve as a proxy for ecological function. By
avoiding impacts to species and the habitats upon which they rely, impacts to ecological functions
will be avoided as well.
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The following specific factors are assessed in the following analysis of effects:
Noise
Water quality
Sediment quality
Sediment transport and bathymetry
Migration, access, and refugia
Forage fish
Benthic infauna and epifauna
Waterfowl
Aquatic vegetation
Plastics and toxicity
3.1 Noise
Changes in noise can result behavioral disturbance or, if loud enough, injury. The following section
describes existing noise conditions and expected effects of the proposed action.
3.1.1 Existing Conditions
Existing sources and levels of airborne as well as underwater noise are described in this section.
3.1.1.1 Airborne Noise
The uplands neighboring the proposed Smersh geoduck farm are rural residential, and they are
zoned as shoreline residential under the current Shoreline Master Plan for Jefferson County. There
are numerous single-family residential houses in the Shine neighborhood which is bordered on the
north side by the heavily trafficked Sstate Route (SR) 104. Between 6,000 and 22,000 vehicles pass
the Shine neighborhood each day on SR 104 (15,000 average annual daily trips) traveling at 60 miles
per hour (WSDOT 2017). Existing noise in the area includes that which is typically found
associated with water-dependent activities (e.g., boat use), residential uses (e.g., vehicle use, lawn
mowers, beach walking), and vehicular traffic. Using the standard that 10 percent of the average
annual daily traffic represents hourly average traffic (WSDOT 2018) leads to 1,500 vehicles per hour
passing near the Shine neighborhood on SR 104. At 60 mph the sound from vehicle traffic is
approximately 75 dBA at 50 feet (WSDOT 2018). This sound level attenuates to approximately 45
dBA at 800 feet which is approximately the halfway point between the Smersh parcel and SR 104.
The estimated noise level based on population density is approximately 40 to 45 dBA (FTA 2006).
3.1.1.2 Underwater Noise
Measurements of ambient underwater noise were recorded at the Hood Canal Bridge in 2004.
Median background peak sound pressure was between 118.2 and 137.5 dBPEAK re 1 μPa and median
root mean squared (RMS) levels were 115 and 135 dBRMS re 1 μPa (Battelle 2005).
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3.1.2 Effects of Noise
Noise-generating elements of the proposed project are consistent with existing use of the
surroundings (small boat use and walking on the beach). Both airborne and underwater noise
would be generated from the proposed project when boats are used to access the project site and
during the operation of pumps for harvest on a 5- to 7-year cycle. The potential to affect fish and
wildlife in relation to noise is described below.
3.1.2.1 Effects of Airborne Noise
The proposed project does not include the use of heavy equipment. Access to the site would occur
about once a month, and more frequently during limited periods for activities such as planting or
harvesting. Access would be via the upland parcels or via boat. The outboard motors typically used
on boats used for aquaculture typically create a noise level of about 60 dBA at 50 feet (Berger et al.
2010). However, once at the site, the engine would be turned off until employees are ready to leave.
Small diesel- or gas-powered water pumps with hoses would be used to harvest the geoducks for
several days every 5 to 7 years. While noise levels of the water pumps have not been directly
measured, they are considerably quieter than the outboards, referenced above, that produce a
sound level of 60 dBA at 50 feet. Based on an ambient noise level of approximately 40 dBA to 45
dBA, terrestrial noise associated with the proposed project is expected to attenuate to ambient
conditions 199 to 285 feet from the pumps. The landward margin of the geoduck planting area is
approximately 160 feet from the ordinary high water line, leading to the conclusion that nearby
residents will be exposed to only slight increases in noise if they approach within close proximity to
the shoreline near the project site.
Noise associated with aquaculture operations during planting, maintenance, and harvesting
activities could, if loud enough, result in temporary displacement of birds and/or masking of
communication among foraging birds. Strachan et al. (1995 as cited in USFWS 2009) observed that
marbled murrelets around heavy boat traffic do not appear to be adversely affected by the ambient
noise of urban areas. Other waterbirds have shown behavioral changes in response to noise, but not
to the extent that would cause population-level effects as long as distances of approximately 164
feet to 328 feet are maintained from nesting habitats (Carney and Sydeman 1999, Borgmann 2010).
Because bald eagles are a state sensitive species in Washington, and protected under the federal
Bald and Golden Eagle Protection Act, there is an emphasis on ensuring that shoreline activities, in
general, do not disturb eagles. WDFW studied the response of nesting bald eagles for a 2-year
period (1993-1994) in relation to recreational pedestrian activity and wildstock geoduck harvest
activities within eight territories in Puget Sound (Watson et al. 1995). Eagles flushed in response to
4 percent of 890 potential disturbances, and only 1 of 34 responses was a result of geoduck harvest
activities. Effects to eagle foraging from geoduck harvest activity was considered statistically
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insignificant at the frequency tested 1, and eagles tended to forage evenly throughout the day with
or without a harvest vessel present. Similar effects are anticipated due to the proposed project.
The threshold for masking marbled murrelet communication is an in-air noise level of 29 dB
sensation level (SL) or 29 dB above ambient noise level (Teachout 2013). This threshold was
informed by two critical hearing demands: (1) communication between conspecifics (at-sea or in
terrestrial habitat), and (2) detection of the presence of corvid predators in terrestrial habitat. It is
unlikely that the noise generated by the proposed geoduck aquaculture operation would result in
masking marbled murrelet communication because the use of water pumps during a wet harvest
(the loudest noise source proposed for the project) is expected to increase noise levels by 15 dBA to
20 dBA above ambient noise levels (assuming 60 dBA produced by the water pump and 40 to 45
dBA ambient noise).
Considering the distances from nesting sites from the proposed project area, negative effects
associated with increased human presence are not anticipated at this site. Even if some short-term
avoidance behavior is observed, there is nothing to indicate that this reaction would impact the
overall foraging ability of birds present in the project area. Therefore, it is unlikely that such
temporary displacement from foraging activities in the limited project area would result in reduced
foraging success, nesting success, or fitness of overwintering birds. This concurs with the
conclusions reached by USFWS (2016), that determined exposures and effects of aquaculture-
related noise to marbled murrelets are insignificant.
3.1.2.2 Effects of Underwater Noise
Underwater noise would also be generated from the motors on boats used to transport gear and
personnel to the project area and the small engines used for the water pumps during a geoduck
harvest. Underwater noise thresholds for fish, cetaceans, pinnipeds, and marbled murrelets are
presented in Table 1.
Table 1 Underwater Noise Thresholds by Functional Hearing Group
Functional Hearing Group Underwater Noise Thresholds
Behavioral Disruption Threshold Injury Threshold
Fish > 2 grams
Fish < 2 grams
Fish all sizes
150 dB RMS
187 dB Cumulative SEL
183 dB Cumulative SEL
Peak 206 dB
Marbled Murrelet 150 dB RMS* 208 dB SEL (barotrauma)
202 dB SEL (injury)
Low-Frequency (LF)
Cetaceans 120 dB RMS** LE,LF,24h:199 dB Cumulative SEL
(non-impulsive sound source)
Mid-Frequency (MF)
Cetaceans 120 dB RMS** LE,MF,24h: 198 dB Cumulative SEL
(non-impulsive sound source)
High-Frequency (HF)
Cetaceans 120 dB RMS** LE,HF,24h: 173 dB Cumulative SEL
(non-impulsive sound source)
1 Frequency of geoduck harvest activities tested by Watson et al. (1995) included two weekday bouts when harvest boats were
present, followed by two weekend control days when boats were absent, for a total of 296 observational bouts and 1,896 hours.
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Functional Hearing Group Underwater Noise Thresholds
Behavioral Disruption Threshold Injury Threshold
Phocid Pinnipeds (PW)
(Underwater) 120 dB RMS** LE,PW,24h: 201 dB Cumulative SEL
(non-impulsive sound source)
Otariid Pinnipeds (OW)
(Underwater) 120 dB RMS** LE,OW,24h: 219 dB Cumulative SEL
(non-impulsive sound source)
1 dB re 1 μPa2 -sec = sound exposure level (SEL)
RMS = root-mean-square; this is the square root of the mean square of a single pile driving impulse pressure event
*USFWS considers this to be a guideline, not a threshold
** NMFS’s interim sound threshold for behavioral effects
Source: NMFS 2016b, Teachout 2013
To estimate underwater noise that might result from geoduck aquaculture, we reviewed Table 3.73
of Wyatt (2008) to find a close approximation of the underwater noise generated from boats that
would be used for the proposed project. In order to estimate the worst-case scenario for underwater
noise, the parameters used for this analysis were the 21-ft Boston Whaler vessel with a 250
horsepower Johnson 2-cycle outboard motor operating at full speed and producing sound
measured at 147.2 dB RMS re 1μPa at 1 meter. Following Equation 1, underwater sound of this level
attenuates to the disturbance sound level for marine mammals 213 feet from the boat. Sound levels
produced by the boat do not reach injury levels for any marine mammal group. Nor do sound
levels reach disturbance or injury levels for murrelets and fish.
Equation 1 R1 (in meters) = R2 (in meters)*10((V-120)/15)
R1 = 1m*10(147.2 dB-120 dB)/15)
R1 = 65 m (213 ft)
Where:
R1 = range in meters of the sound pressure level; R2 = distance from the sources of the initial
measurement; V = transmission loss; and dB = decibels
3.1.3 Summary of Noise Effects
According to NMFS’s 2009 assessment of potential impacts to endangered species due to geoduck
aquaculture activities, “A very low level of vessel operations will be associated with the
aquaculture activities (small and larger work boats and barges). Vessels would remain relatively
immobile until work is complete, with minimal sound and insignificant potential for disturbance.”
There is no evidence that increases in either airborne or underwater noise from the use of boat
motors or water pumps associated with the rearing and harvest of geoducks would result in
negative effects to fish and wildlife species. Noise resulting from aquaculture operations
throughout Washington State was reviewed with respect to potential effects to Endangered Species
Act (ESA-listed fish, marine mammals, and marbled murrelets (NMFS 2009, USFWS 2009, NMFS
2011). These reviews found that noise levels did not exceed disturbance thresholds that would
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affect foraging, migration, reproduction, or fitness for any of the ESA-listed species in Puget Sound.
The proposed shellfish aquaculture operation in Squamish Harbor would not significantly alter
noise above existing background conditions. Therefore, harvest operations are not anticipated to
increase underwater noise to a level that will result in a loss of ecological functions
3.2 Water Quality
This section describes existing water quality conditions and the expected effects of the proposed
project.
3.2.1 Existing Conditions
Water quality effects are a function of water circulation (or flushing rate and transportation) and
inputs into the system. Due to its proximity to the entrance to Hood Canal, Squamish Harbor
flushes quickly compared to southern Hood Canal. No waters near the project area are listed on the
Federal Clean Water Act Section 303(d) list (Ecology 2018), indicating that upland sources of
pollution are low and circulation maintains good water quality parameters.
3.2.2 Effects to Water Quality
Potential effects to water quality and fish and wildlife species or their habitat are different for the
various phases of potential aquaculture activities. The following discussion is broken down into (1)
filtration effects and (2) harvest effects.
3.2.3 Filtration Effects
Per Thom et al. (2008), Pacific Northwest estuaries are light limited, which reduces the depth at
which eelgrass and other light-dependent species (e.g., macroalgae/kelp) can be successful.
Shellfish aquaculture can result in a beneficial reduction in turbidity due to removal of
phytoplankton and particulate organic matter through filtration (Peterson and Heck 2001, Newell
and Koch 2004, Cranford et al. 2011). By consuming phytoplankton and particulate organic matter,
shellfish decrease turbidity, thereby increasing the amount of light reaching the sediment surface
that is available for photosynthesis (Dame et al. 1984, Koch and Beer 1996, Newell 2004, Newell and
Koch 2004). Improvements to water clarity and light penetration can improve habitat conditions
that promote the growth of submerged aquatic vegetation (SAV) and other aquatic vegetation.
A large body of literature indicates that shellfish aquaculture, or the presence of a dense bivalve
community, may provide some control of human nutrient loading to water bodies (Newell 2004,
Shumway et al. 2003, Newell et al. 2005, Burkholder and Shumway 2011, Kellogg et al. 2013, Banas
and Cheng 2015, Bricker et al. 2015). Bivalves remove more nutrients from the water column than
they input as biodeposits, which can have a net benefit to water quality. As bivalves filter organic
matter from the water column, they assimilate nitrogen and phosphorus into their shells and tissue.
When shellfish are harvested, the sequestered nutrients are permanently removed from the system.
According to Newell (2004), this process of bioextraction is one of the only methods available that
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removes nutrients after they have entered an aquatic system, which can then make that system
more resilient to nutrient loading and, ultimately, decreases in dissolved oxygen. High nutrient
loading, and resulting decreases in dissolved oxygen, are a known problem in Hood Canal.
Similarly, bivalve filter-feeding also serves an important role in improving water quality conditions
through benthic-pelagic coupling, which is when biodeposits become incorporated into surficial
sediments, and microbially mediated processes facilitate nitrification-denitrification coupling to
permanently remove sediment-associated nitrogen as nitrogen gas.
The amount of benefit to water quality is dependent on species-specific filtration rates. A recent
effort to calculate filtering capacity within south Puget Sound (Ferriss 2015) compiled clearance
rates for Pacific oyster, Manila clam, and geoduck (Table 2). According to Banas and Cheng (2015),
a modeling study that used the data compiled by Ferriss (2015), the potential for local control by
shellfish was shown to be possible in areas with reduced circulation such as Henderson, Eld,
Totten, Hammersley, and upper Case inlets, and Oakland Bay. While Banas and Cheng’s study
focused on southern Puget Sound, Hood Canal exhibits similar circulation patterns and clearance
rates when compared to southern Puget sound. Therefore, shellfish filtration could have a positive
influence on local water quality parameters, even if small compared to the inputs into the system
from residential development, municipal wastewater, agriculture, or other non-point sources.
Table 2 Clearance Rate Calculations for Pacific Oyster, Manila Clam, and Geoduck
Species Indiv. Wwet (g) L hr-1 indiv-1 L hr-1 Wwet-1 Source
Pacific oyster 11.52 3 0.260 Kobayashi et al. 1997, Ruesink et al. 2006
Manila clam 18.19 1 0.060 Ruesink et al. 2006, Solidoro et al. 2003
Geoduck 980 3 0.003 Davis 2010
Source: Ferriss 2015, Banas and Cheng 2015
An example of the potential benefits offered by shellfish filtration and nutrient sequestration is
provided by Kellogg et al. (2013), who partially quantified the removal of nutrients from the water
column at a subtidal oyster reef restoration site compared to an adjacent control site in the
Choptank River within Chesapeake Bay, Maryland. The authors indicated that denitrification rates
at the oyster reef in August were “among the highest ever recorded for an aquatic system.” In
addition, a significant portion (47% and 48%) of the available nitrogen and phosphorus were
sequestered in the shells of live oysters and mussels. An ancillary benefit of the shellfish reef
structure, which is also true for shellfish aquaculture, was that the structure and faunal composition
provided ample microhabitats for communities of nitrifying microbes. One of the conclusions by
Kellogg et al. (2013) was that oyster reef restoration could be considered a “safety net” to reduce
additional downstream impacts to water quality. Because geoduck aquaculture provides many of
the same benefits, with the added benefit of the total removal of anthropogenically derived
nutrients at harvest, commercial shellfish aquaculture can be considered a net benefit to water
quality ecosystem functions.
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3.2.4 Harvest Effects
During harvest, suspended sediment and turbidity can be increased for a short period near the
harvest activity. Harvest events are limited in space (about 0.1 acre per day), duration (4 to 6 hours
per day), and occurs infrequently (once every 5 to 7 years) compared to the entire culture cycle. The
intensity and duration of turbid conditions are related to the concentration of suspended sediment,
suspended sediment grain size, water temperature, currents, and tidal flow conditions at the site
(NMFS 2009). Golder (2016) modeled sediment movement and suspension of sediment (primarily
sand) disturbed during a geoduck harvest in Case Inlet. Sediment particles were shown to settle
back to the bed rapidly and only a minor fraction was transported a distance of about 300 feet. This
result is consistent with total suspended solids (TSS) collected by Short and Walton (1992) during a
geoduck harvest in the Nisqually Reach, where it was noted that most sediment was deposited
within 3 feet of the harvest hole, and only “small quantities of material” were transported beyond
150 feet from the harvest zone. TSS measured by Short and Walton (1992) at the harvesting location
ranged from 4 to 21 mg/L. While a visible harvest plume persisted for approximately 30 minutes
after harvest and extended approximately 330 feet down current, almost all TSS measurements
within 131 feet of the harvest were shown to be within 1 mg/L of background TSS.
New research from Fisheries and Oceans Canada, Pacific Biological Station in British Columbia,
Canada, has shown similar or lower effects from wet geoduck harvest events. A 2-year research
program in both intertidal and subtidal habitats reported that the measurable sediment plume
generated during a geoduck harvest event was generally limited to within approximately 16 feet of
the harvest plot, and TSS levels were similar to those reported during typical storm conditions (Liu
et al. 2015). In addition, a harvest event did not result in significant changes to sediment grain size
down-current.
Cornwell et al. (in review) evaluated the nutrients released from a typical commercial geoduck
harvest using low-pressure water hoses. The study found that: (1) the amount of nutrients released
into the water column during harvesting is low, (2) the moderate concentrations of nitrogen and
phosphorus found in sediments and released during harvest make a relatively small contribution to
overall nutrient discharges into Puget Sound, and (3) localized effects are likely to be negligible.
A typical geoduck harvest event is limited in space (about 0.1 acre for 1 day), duration (4 to 6
hours), and occurs infrequently with respect to the entire culture cycle (i.e., 5- to 7-year grow-out
period prior to harvest). In comparison, a typical storm event in Puget Sound occurs once per
month and transports material over thousands of kilometers. Therefore, both the timing and
intensity of activities are well below the natural disturbance regime of a typical Puget Sound habitat
and harvest is not anticipated to result in loss of ecological functions.
Exposure to high levels of suspended sediment can cause behavioral stress in fish (e.g., gill flaring),
sublethal effects (e.g., gill damage, increased susceptibility to disease), or reduced survival and
growth. Newcombe and MacDonald (1991) suggested that a good indicator of suspended sediment
effects is the product of sediment concentration and duration of exposure. Fisher et al. (2008)
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evaluated whether the TSS generated during a harvest event could result in significant effects to
fish using the suspended sediment risk assessment model developed by Newcombe and Jensen
(1996). The results indicate that fish are likely to exhibit avoidance responses to the localized TSS
levels generated during a harvest event. Because there is no confinement of the harvest area (i.e.,
the site is located along an open shoreline) there is no mechanism to entrap fish and expose them to
increased suspended sediments for a significant amount of time.
Published literature that addresses suspended sediment effects to juvenile and larval estuarine
fishes also report limited effects at the concentrations generated during a geoduck harvest event.
Juvenile Chinook salmon have been observed to increase their rates of foraging in relation to
increased turbidity (18-150 nephelometric turbidity units [NTUs]), which was attributed to the
increase in cover provided by turbid waters (Gregory and Northcote 1993, Gregory 1994). The
maximum concentration of turbidity that juvenile Chinook salmon experienced before reduced
foraging was observed was 150 NTUs for individuals that were 2 to 3 inches in fork length
(Gregory 1994). Studies have also reported increased feeding incidence and intensity for larval
Pacific herring at TSS concentrations ranging from 500 mg/L to 1,000 mg/L (Boehlert and Morgan
1985). Boehlert and Morgan (1985) attributed the enhanced feeding to improved “visual contrast of
prey items on the small perceptive scale used by the larvae.” Finally, Griffin et al. (2012) noted that
TSS levels of 400 mg/L did not result in adverse effects for Pacific herring larvae for exposure times
of 16 hours. All of the TSS and turbidity levels noted in these examples are either within or
significantly higher than levels measured during a geoduck harvest, indicating that a harvest
would be unlikely to raise TSS to a level or duration that would have negative effects on salmon
and forage fishes. Also, environmental effects of geoduck harvests have been shown to be similar
to, or less than, the effects of periodic natural storms. Therefore, harvest activities are unlikely to
have a negative effect on fish.
3.2.5 Summary of Effects to Water Quality
Bivalves can improve water quality and mitigate anthropogenic sources of nitrogen in coastal
systems through filtration of nitrogen by absorbing phytoplankton in the water column (Newell
2004, Lindahl et al. 2005, Zhou et al. 2006). Conversely, a harvest event can potentially impact water
quality. Although a harvest event may increase suspended sediment for short periods of time (one
to two tidal cycles), it is typically confined to a small area (from 3 feet to 150 feet from the harvest
area) and occurs infrequently (every 5 to 7 years).
Fish would be expected to either avoid the sediment plume generated during a geoduck harvest or
use the plume as a foraging opportunity. Suspended sediment and turbidity levels measured
during geoduck harvest events were within or lower than the range in which juvenile Chinook
salmon and Pacific herring larvae were observed to successfully forage (Boehlert and Morgan 1985,
Gregory 1994). Overall, effects from suspended sediments are considered insignificant and habitat
may potentially be improved in local areas if shellfish improve water quality conditions. No net
loss of ecological function is anticipated due to water quality impacts from geoduck aquaculture.
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3.3 Sediment Quality
This section describes existing sediment quality conditions and the expected effects of the proposed
action.
3.3.1 Existing Sediment Conditions
No sediment quality studies have been completed for the specific project site but the lack of historic
industrial development in Hood Canal indicates that sediment is unlikely to contain deleterious
substances regulated by the state. Substrate at the Smersh site consists mainly of well-sorted, clean
sand.
3.3.2 Effects to Sediment Quality
Bivalve filter feeding serves an important role through benthic-pelagic coupling, which is the
consumption of nutrients (via filtration of phytoplankton) and creation of biodeposits (feces and
pseudofeces). Nitrogen and phosphorus that are not digested are excreted as soluble ammonia and
biodeposits in the form of feces. When these biodeposits become incorporated into aerobic, surficial
sediments, microbially mediated processes facilitate nitrification-denitrification coupling to
permanently remove sediment-associated nitrogen as nitrogen gas (Newell 2004, Kellogg et al.
2013).
The biodeposits created through bivalve filter feeding contribute to organic materials in the
sediment surface, as described above.
A study conducted for the Washington Sea Grant Geoduck Aquaculture Research Program
assessed the influence of geoduck aquaculture on sediment nutrient regeneration (Cornwell et al. in
review). During the culture period of the study, porewater nutrient concentrations of nitrogen and
soluble reactive phosphorus were higher at culture sites than at reference sites. The release of
nitrogen and phosphorus species during harvest resulted in a minor increase in nutrient
concentration of water surrounding the geoduck harvest, suggesting that the liquefication of
sediments does not release a large percentage of the accumulated nutrients in the porewater. The
authors concluded that when extrapolated to all Puget Sound cultivated geoduck harvest on a daily
basis, the harvest release of nutrients represents an inconsequential fraction of anthropogenic
inputs into Puget Sound, leading to the conclusion that geoduck harvest is unlikely to reduce
ecological function due to sediment or water quality effects.
Grounding of vessels may occur occasionally and temporarily during harvest of geoducks. Vessels
would have approximately 20 square feet of ground contact for up to 6 hours per day during
approximately 10 low tide workdays per year. Because the proposed farming area is composed of
well-sorted, clean sand, no effect is anticipated to fish or wildlife habitat. Sand does not support
attachment of flora and fauna that would provide feeding or refuge opportunities for local fish and
wildlife. Additionally, because sand within the proposed planting area is loosely consolidated, any
visible scars or footprints from the grounded vessel would be washed away within one tidal cycle
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of the grounding. Impacts from grounding would be similar to what might be expected from an
individual walking the beach at low tide. An occasional crab or fish may become entrapped
beneath the grounded vessel but no long term negative impacts would occur to fish and wildlife
populations nor the habitats upon which they rely for breeding, rearing, migration, or growth to
maturity.
3.4 Sediment Transport and Bathymetry
This section describes existing sediment transport and bathymetry conditions and the expected
effects of the proposed action.
3.4.1 Existing Conditions
Sediment along the north shore of Squamish Harbor is primarily sandy in the lower elevations with
gravel and cobble on the upper intertidal beach. The beach slopes gradually and has a relatively
high exposure to waves, winds, and currents during storm events. East of the project area there is a
high bluff composed of various layers of glacial sediment. The bluff is characterized by massive
erosion that threatens several structures on the top of the bluffs (ESA Adolphson et al. 2008). The
shoreline is classified as unstable recent landslide (Ecology 1978). Net shore-drift is to the west as
indicated by sediment accumulations on the east side of obstacles and the westward prograding
spit at the mouth of Shine Creek ESA Adolphson et al. 2008). In the nearshore, eelgrass beds are
patchy in the intertidal zone and continuous below MLLW. Shoreline armoring is prevalent along
the north shore of Squamish Harbor, with about 26 percent of this reach armored (Jefferson County
2008). A boat ramp extends onto the beach next to the project parcel, with a parking lot located on
fill. The effect of the armoring and boat ramp are unclear, but are likely having at least a minor
effect on sediment erosion and input.
3.4.2 Effects to Sediment Transport and Bathymetry
No dredging or placement of fill is proposed as part of the project. The two types of potential
disturbances associated with shellfish aquaculture that could affect sediment transport and
bathymetry include: (1) addition of gear that slows the transport of sediments, and (2) pulse
disturbances due to effects of harvest activities (Dumbauld et al. 2009). These potential disturbances
are described below.
3.4.3 Addition of Gear
PVC culture tubes used in geoduck clam aquaculture can slow currents near the substrate, resulting
in accumulation of sediment under and around the PVC tubes. Golder (2011) estimated the
potential accumulation of sediment within the tubes from an existing geoduck aquaculture
operation in south Puget Sound. Based on a visual inspection, an average height of 2.5 ±0.5 inches
of sediment accumulation was reported within the 4 inches of tube that was exposed above the
sediment bed. This equates to a volume of approximately 31.4±6.3 cubic inches per tube. Golder
(2011) then calculated net accumulation over a 1-acre area to be approximately 29.3 cubic yards (cy)
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of sediment. This minor amount of net accumulation is expected to rapidly redistribute through
wave and current action after 1 or 2 tidal cycles (or a few days with typical wave conditions)
following the removal of PVC culture tubes.
3.4.4 Harvest Activities
During a geoduck harvest, the overlying sediments are loosened around the clam by adding water
through a 0.5-inch- to 0.6-inch-diameter hose. Although this activity results in minor, localized
changes in elevation and sediment grain size, both quickly return to baseline conditions post-
harvest. At Samish Bay, Horwith (2009) reported that minor post-harvest elevation drop was not
evident within 1 month of a harvest. Post-harvest resettling of sediments occurs as water content
decreases, leading to an increase in shear strength and resistance to erosion. In laboratory
experiments with fine-grained marine sediment, resistance to resuspension was shown to double
approximately every 12 hours (Southard et al. 1971 as cited in Short and Walton 1992). Therefore,
the sediment redeposited during a harvest event will tend to regain its original shear strength
within 1 or 2 days after harvest.
Grounding of vessels may occur occasionally and temporarily during harvest of geoducks. Because
the proposed farming area is composed of well-sorted, clean sand, no effect is anticipated to fish or
wildlife habitat. Sand does not support attachment of flora and fauna that would provide feeding
or refuge opportunities for local fish and wildlife. Additionally, because sand within the proposed
planting area is loosely consolidated, any visible scars or footprints from the grounded vessel
would be washed away within one tidal cycle of the grounding. Impacts from grounding would be
similar to what might be expected from an individual walking the beach at low tide. An occasional
crab or fish may become entrapped beneath the grounded vessel but no long term negative impacts
would occur to fish and wildlife populations nor the habitats upon which they rely for breeding,
rearing, migration, or growth to maturity.
3.4.5 Summary of Effects to Sediment Tranport and Bathymetry
In summary, geoduck harvest or the presence of PVC culture tubes does not lead to significant
negative effects to sediment transport or bathymetry. Minor changes in elevation may persist for up
to 1 month, but these effects are considered to be short-term with no lasting changes to the
surrounding sediment structure. The changes associated with geoduck aquaculture operations are
insignificant compared to the dynamic nature of sediment distribution potential (e.g., storms,
littoral drift, etc.) along the shoreline associated with the project area. No loss of ecological function
is anticipated due to changes in sediment transport or bathymetry.
3.5 Migration, Access, and Refugia
This section describes existing migration, access, predation, and refugia conditions and the
expected effects of the proposed project.
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3.5.1 Existing Conditions
Shine Creek, approximately 1.5 miles to the west supports chum and coho salmon and cutthroat
and steelhead trout spawning. The Shine Creek estuary is likely rearing habitat for natal and non-
natal juvenile pink, chum, coho, and Chinook salmon (ESA Adolphson et al. 2008). A small stream
enters Squamish Harbor near the project site (>150 feet to the north) and is presumed cutthroat
trout habitat (Correa 2003). This small stream does not support salmon because access to upstream
habitat is hindered by (1) the very small size of the stream, and (2) the steep gradient where the
stream flows through shoreline armoring (i.e., boulder riprap). Sand lance spawning has been
documented along the beach to the west of the project and herring are known to spawn in the
eelgrass beds offshore (Penttila 2000, Long et al. 2003).
The project site is a sandy, gravelly beach with no man-made structures. Juvenile salmonids and
other fish may use the intertidal area, when inundated, for migration, access, and refugia.
3.5.2 Effects to Migration, Access, and Refugia
PVC culture tubes are the only material planned for use in aquatic areas for this project. PVC tubes
extend only 3 to5 inches above the substrate surface No other equipment is planned for use in the
project and no excavation or alteration of the beach is planned. Culture tubes will not block
migration or access to habitat in the project area.
The planting area is over 150 feet from the mouth of the nearby stream. All species of Puget Sound
salmon are well documented utilizing estuarine and nearshore habitat in their migrations from
their natal freshwater watersheds to the ocean and back (Duffy et al. 2010). Salmon are known to
feed in habitat similar to that found in the project area, ingesting amphipods, copepods, larval fish,
and terrestrial insects (Fresh et al. 2006). Depending on the tidal cycle, fish can easily swim over, or
around culture tubes if necessary. Many researchers have reported that aquaculture gear is similar
(or superior) to adjacent eelgrass habitat in terms of the diversity and abundance of benthic fauna
and fish (Meyer and Townsend 2000, DeAlteris et al. 2004, Pinnix et al. 2005, Powers et al. 2007).
Sand lance spawn in sandy substrate in the upper intertidal zone between MHHW and +5 feet
(MLLW) (Pentilla 2007). Because project planting, grow-out, and harvest will not extend above +2
feet elevation, access to sand lance spawning habitat will not be reduced.
As long as the gear is properly maintained, PVC geoduck culture tubes in the intertidal area are not
expected to affect migration, access, or refugia pathways for fish that utilize shallow water. The
presence of aquaculture gear may even serve as additional foraging habitat or cover from
predators. Because occasional vessel grounding in the highly dynamic sandy shoreline
environment will be of short duration and occur only occasionally during a 2-year harvest period,
no impacts to areas of fish and wildlife migration, access, and refugia are anticipated. No loss of
ecological function is expected to occur due to effects to migration, access, and refugia.
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3.6 Forage Fish
This section describes existing forage fish conditions and the expected effects of the proposed
project.
3.6.1 Existing Conditions
Sand lance spawning has been documented along the beach to the west of the project and herring
are known to spawn in the eelgrass beds offshore (Penttila 2000; Long et al. 2003). Sand lance
spawn in sandy substrate in the upper intertidal zone between MHHW and +5 feet (MLLW)
(Pentilla 2007) and typically select substrate with a diameter between 0.2 and 0.4 millimeters. In the
project area, the substrate found in the elevation range sand lance typically spawn is primarily
gravel, which is sub-optimal for sand lance spawning. A dense eelgrass bed is found in the subtidal
zone at least 16 feet from the proposed planting area.
3.6.2 Effects to Forage Fish
There are two potential effects to forage fish from the proposed geoduck aquaculture operation,
including: (1) spawning habitat could be overlapped, and (2) forage fish spawning areas could
receive suspended sediments during a harvest event. The potential for these effects to be significant
to forage fish or their habitat in the project area are discussed below.
3.6.3 Spawning Habitat Overlap
The proposed culture activities are not located at shoreline elevations where sand lance spawn.
Culture will be confined to the intertidal and subtidal zone below +3 MLLW, while the forage fish
spawn elevation begins at +5 MLLW. Therefore, the proposed project is not expected to impact
spawning habitat of these forage fish species. When the site is accessed by boat, boats would not be
beached above +5 ft MLLW. Boats will be moored or grounded in areas waterward of +5 ft MLLW.
Foot traffic for routine maintenance and beach surveys for debris will use consistent paths and will
not occur where potential forage fish spawning habitat may exist.
In some cases, aquaculture gear can provide a new substrate for herring spawn attachment in an
otherwise unstructured environment. Growers will be trained by a WDFW-certified biologist to
recognize herring spawn. If herring spawn is observed within the geoduck farm, then those areas
will be avoided until the eggs have hatched. Vessels will not be grounded in areas where herring
spawn is observed. This conservation measure has been adopted by the Corps as part of the ESA
consultation process with the Services on the Programmatic Consultation for Shellfish Activities in
Washington State Inland Marine Waters (NMFS 2016a, USFWS 2016).
Therefore, the proposed project will not result in a loss of ecological function due to the project
overlapping forage fish spawning habitat.
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3.6.4 Sediment Mobilization
If forage fish do spawn near the project area, there is a low potential for adversely impacting
spawning beds with sediment mobilized during harvest. Fines make up a small percentage of the
farm substrate, and sands (because they are denser) drop out of the sediment plume within a few
meters (Short and Walton 1992, Golder 2011). Therefore, there will be no loss of ecological function
due to effects to forage fish spawning habitat resulting from sediment mobilization.
3.6.5 Summary of Effects to Forage Fish
Because the project does not overlap sand lance spawning habitat, and because farming activity will
halt if herring spawn are observed within the project area, no loss of ecological function is
anticipated due to negative effects to forage fish spawning. Additionally, because sediments
mobilized during geoduck harvest settle out of the water column within a few feet of harvest
activity, no net loss of ecological function is anticipated due to mobilized sediment.
3.7 Benthic Infauna and Epifauna
This section describes existing benthic infauna and epifauna conditions and the expected effects of
the proposed action.
3.7.1 Existing Conditions
Observations of epifauna in the proposed project area were consistent with Puget Sound sandflat
habitats (Dethier 1990, Dethier and Schoch 2005). Species observed at the project site include
various amphipods, various isopods, various polychaete worms, sand sole, English sole, various
sculpins, various shrimp, Dungeness crab, red rock crab, and various hermit crabs,
3.7.2 Effects to Benthic Infauna and Epifauna
Geoduck aquaculture may affect the benthic faunal community, including community changes
during: (1) culture tube placement and use in 1st two years of grow out, and (3) harvesting. The
effects of each action, the relative recovery period, and potential effects to benthic fauna are
discussed below.
3.7.3 Culture Tube Placement Effects
Placement of PVC culture tubes is not expected to significantly affect benthic epifauna. Once the
tubes are placed, they are rapidly encrusted with epibiota that create a reef-type structure and a
biogenic source for associated food organisms of juvenile salmonids (Cheney 2009, VanBlaricom et
al. 2013). Specific studies evaluating the use of geoduck farms by salmonids and other fish are
ongoing. However, based on shellfish aquaculture studies in similar sandflat habitats, the effects
from culture tubes are likely beneficial to salmonids and other fishes because of the additional food
resources available (Cheney 2009, NMFS 2011, NMFS 2016b, USFWS 2016). In fact, NMFS (2016b)
concluded that increased densities of benthic infauna at intertidal geoduck clam aquaculture sites
may persist even after removing protective tubes. For example, at one aquaculture site in southern
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Puget Sound, ENVIRON 2008 (as cited in NMFS 2016b) found the average number of infaunal
benthic organisms per sediment core from an unprotected seeded area was greater than the density
of infaunal benthic organisms found in a reference area located outside of the aquaculture site.
Thuesen and Brown (2011, as cited in NMFS 2016b) observed an increase in biodiversity of benthic
fauna in an intertidal geoduck farm using PVC tubes, and species richness was significantly higher
compared to a control site and compared to a geoduck farm without tubes. Data from the Pacific
Shellfish Institute (Cheney 2009) documented up to a 30 percent increase of harpacticoid copepods
(e.g., typical salmonid prey items) on PVC tubes at an existing geoduck aquaculture plot in Spencer
Cove on Harstine Island.
3.7.4 Harvest Effects
Shellfish harvest disrupts the sediment and results in the loss of some benthic fauna (Hall and
Harding 1997, Ferns et al. 2000), although that does not mean that the loss is a significant impact to
that resource. The recovery rate of infauna varies in response to the timing and magnitude of the
disturbance as well as the location of the site to populations of organisms and the mobility of
organisms affected (Dernie et al. 2003). Intertidal habitats are exposed to a wide range of natural
disturbance regimes that are dominated by physical processes such as tides, storm-generated
waves, inter-annual variation in climate, and nearshore sediment transport. It is generally assumed
that benthos found in more dynamic sand and gravel habitats will recover more quickly following
physical disturbance than those found in less energetic muddy habitats based on the adaptive
strategies of the respective assemblages found in these environments (Kaiser et al. 1998, Ferns et al.
2000). Microcosm studies appear to support this hypothesis (Dernie et al. 2003). In general, benthic
infauna recovered very quickly (weeks to months) in terms of both diversity and abundance from
small-scale disturbances, especially within clean sand communities.
Price (2011) and VanBlaricom et al. (2015) reported that potential effects to benthic invertebrates
from a geoduck harvest event are within the natural disturbance regime. This work compared the
benthic community within harvested and non-harvested plots and found that effects to benthic
infauna during geoduck harvest are similar to effects resulting from wind and wave energy due to
natural storms. Detectable disturbances quickly become indistinguishable from control plots
(VanBlaricom et al. 2015). Recovery of the benthic infauna is relatively rapid after a geoduck
harvest event because infauna are still preserved in roughly the same location, leading to rapid
recolonization (Price 2011). In addition, because a harvest cycle occurs every 5 to 7 years, there
would unlikely be compounded effects due to repeated harvesting of the same area (Liu et al. 2015).
The main conclusion from VanBlaricom et al. (2015) was that communities in Puget Sound are well
adapted to accommodate various types of disturbance. Because the frequency of disturbance from
geoduck harvest occurs at a much lower rate than storm events, infaunal and epifaunal populations
are unlikely to experience long-term negative effects. Based on this evaluation, it was determined
that there were no long-term measurable effects to resident populations of invertebrates from
geoduck harvest, and the intensity of potential effects was equivalent to natural disturbances.
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3.7.5 Summary of Effects to Benthic Infauna and Epifauna
Overall, the research indicates that the benthic infaunal and epifaunal community is not affected or
returns to baseline, or near baseline conditions, once the gear is removed or harvest is complete
(VanBlaricom et al. 2013, Price 2011, McDonald et al. 2015, Liu 2015, VanBlaricom et al. 2015). Small
benthic invertebrates produce more than one generation per year and thus have rapid
recolonization rates. Intertidal species have adapted to habitat changes. Chronic low-intensity or
sporadic medium-intensity intertidal substrate disturbances are within the range of “behavioral or
ecological adaptability” (Jamieson et al. 2001). Therefore, no net loss in ecological function is
anticipated due to impacts to benthic infauna and epifauna.
3.8 Waterfowl
3.8.1 Existing Conditions
Embayments of North Puget Sound provide important breeding and rearing habitat for waterfowl
and shorebirds. A variety of diving and dabbling ducks are likely to use the shorelines near the
proposed project for foraging, breeding, and loafing. The clean, well-sorted sand at the proposed
project site does not currently provide good foraging habitat for diving and dabbling ducks. The
sandy beach may provide foraging opportunities for shorebirds during low tides.
3.8.2 Summary of Effects to Waterfowl
Studies of waterfowl use in aquaculture farms have shown either positive impacts (e.g. increasing
avian species richness and abundance due to increased foraging opportunities) or benign impacts
(eliciting no significant difference in use from natural beds). Through their foraging habits,
migrating marine shorebirds can significantly alter the community structure of wild bivalve
populations in soft-bottom intertidal areas (Lewis et al. 2007). At shellfish aquaculture sites, some
species of marine birds feed directly on the shellfish products themselves (Dankers and Zuidema
1995), while others feed on the macrofauna and flora that colonize shellfish aquaculture gear
(Hilgerloh et al. 2001). Shellfish growers have documented numerous bird species foraging on their
shellfish beds, including scoters, dunlins, killdeer, godwits, sand pipers, eagles, great blue herons,
and gulls. Figure 3 presents a few of the species mentioned using shellfish beds for foraging habitat.
Due to the relatively recent history of geoduck aquaculture, and the fact that intertidal geoduck
beds are exposed for a short portion (approximately 6%) of the culture cycle, there are limited
examples that illustrate how birds interact with geoduck aquaculture gear. However, there is both
anecdotal evidence and some photography to show potential interactions. One of the best examples
is the mutually beneficial relationship between shellfish aquaculture practices and scoters. In some
areas, geoduck nursery tubes, oyster crops, and culture gear will get coated with sets of mussels.
The young mussels attract scoters that provide a service to growers by grazing the fouling mussels
off the crops and gear. At the Foss farm in Case Inlet, crews removed nets and when they returned
the following night to clean out the mussels, they were gone. They removed more nets and
deployed a GoPro® camera to discover scoters were cleaning off what ended up being thousands of
pounds of mussels (Figure 4).
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Figure 3 Marine Birds Foraging in Shellfish Beds
Note: least sand pipers on oyster bags (top left), dunlins in oyster bed (top right), and godwits (bottom) around and on oyster bags.
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Figure 4 Scoters Foraging on Mussels Encrusting Geoduck Culture Tubes
Note: photograph taken using a Go-Pro camera on the Foss farm in Case Inlet.
Source: Dewey, pers. comm., 2015
Shorebirds may be temporarily displaced from the farm during site inspections or harvesting but
there are numerous undisturbed shorelines in the near vicinity that provide foraging and loafing
opportunities during such short duration and temporary activities.
3.9 Aquatic Vegetation
This section describes existing submerged aquatic vegetation (SAV) conditions and the expected
effects of the proposed action.
3.9.1 Existing Conditions
A dense bed of eelgrass extends from approximately -3 ft MLLW, waterward of the project area to
an unknown depth. A narrow band of sparse, patchy eelgrass is adjacent to the dense native
eelgrass bed between approximately -2 and -3 feet MLLW. No native eelgrass was identified
landward of the upper edge of the patchy eelgrass bed. Several very sparse patches of non-native
dwarf eelgrass (Zostera japonica) were observed distributed throughout the project area.
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Macroalgae beds are not found in or near the project area. Typical of sand- and silt-dominated
habitats in Puget Sound, ulvoids were present at a very low density (<2% surface coverage)
throughout the mid- and low-intertidal zone (approximately +2 to -2 feet MLLW) attached to hard
objects such as derelict clam shells.
3.9.2 Effects to Aquatic Vegetation
Macroalgae density is anticipated to increase in the project area due to geoduck farming as the PVC
culture tubes provide solid substrate required by macroalgae for attachment and growth.
Because the project will be located outside of a 16-foot protective buffer from native eelgrass, no
negative effects are anticipated to occur to eelgrass due to the proposed project. No net loss in
ecological function will occur due to impacts to aquatic vegetation.
3.10 Plastics and toxicity
3.10.1 Existing Conditions
Plastics are commonly used in the marine environment. A few examples of marine plastics are
buoys, floats, nets, fishing line, and boat components. Increased generation of both macroplastics
and microplastics have been identified as potential as concerns for aquaculture equipment.
Macroplastics are defined as any solid material greater than 5 millimeters (mm) or 0.2 inches in
diameter, while microplastics are materials less than 5 mm that are primarily composed of synthetic
polymers (Baker et al. 2011, Davis and Murphy 2015).
Microplastics may enter the marine environment from primary sources (e.g., pellets in facial scrubs
entering marine waters through water treatment plant effluent), or from the disintegration of larger
plastic materials. Microplastics were sampled from the upper 1.6 ft of the Puget Sound water
column by the Center for Urban Waters and the University of Washington (Baker et al. 2011). The
study reported that microplastics are ubiquitous in all coastal waters. Within Puget Sound,
microplastic concentrations were found to be highly variable in space and time, did not appear to
be correlated to specific source locations, and were similar to levels in the open North Atlantic and
Eastern Pacific. Comparatively, Davis and Murphy (2015) collected material directly from beaches
rather than from the water column. This study reported that the majority of microplastics observed
were located in north and central Puget Sound, typically in close proximity to marinas and urban
centers. Styrofoam was by far the majority (75% of the count) of anthropogenic microdebris found
in these areas, followed by plastic fragments (9%) and glass (12%). There appears to be a strong
positive correlation between the areas of high microplastic abundance and population density.
3.10.2 Summary of Effects from Plastics and Toxicity
Concerns have been raised at Shoreline Hearings Board hearings regarding the potential for
aquaculture activities to release micro- or macro-plastic debris or to leach metals into the
environment (Baker 2012). No PVC is planned for use in this project so leaching of metals or other
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toxic chemicals from PVC will not occur. PVC culture tubes planned for this project are made of
high-strength, long-wearing High Density Poly-Ethylene (HDPE) that, once lodged into the
sediments, are very difficult to dislodge.
The potential to create microplastics was thoroughly reviewed by Dr. Joel Baker in 2012. Dr. Baker
found that PVC tubes, which are much less abrasion resistant than HDPE, are unlikely to degrade
based on the low ultraviolet exposure (i.e. tubes are under water most of the time), low wave
energy, and debris management plans (Baker 2012). To confirm that microplastics were not created
within a tube field, bulk sediment samples were taken from existing geoduck tube fields and tested
in an EPA-approved lab. Dr. Schenk (2011) reported that there was no evidence of microplastics in
the sediment samples. Further confirmation that microplastics are not created due to geoduck
aquaculture was based on a review of stomach samples from fish collected in geoduck tube fields.
Dr. VanBlaricom (2013) testified that, out of 235 fish collected from geoduck aquculture farm, there
was no evidence of microplastics in their stomachs. While there are no known data specific to the
potential to generate microplastics from the use of HDPE materials, there is no evidence that
microplastics are a significant issue driving net loss of fish or wildlife habitat in Puget Sound (Davis
and Murphy 2015). According to Schoof (pers. comm., 2015), the life cycle of HDPE used for
aquaculture is much longer than manufacture’s specifications (e.g., decades vs. 2 years). Therefore,
due to HDPE’s strength and integrity, it is unlikely that use of HDPE materials would significantly
contribute to the generation of microplastics.
In a review of potential impacts of microplastics in the marine environment, Andrady (2011)
commented that microplastics were most likely generated on beaches, which would have extended
exposure to light and weathering if not collected. The author mentioned that beach cleanups are an
effective mitigation strategy to avoid or limit the creation of microplastics. He concluded his
comments on beach cleanup by stating, “Beach cleanup therefore can have an ecological benefit far
beyond the aesthetic improvements of the beaches, and by reducing microplastics, contributes
towards the health of the marine food web.” The conditions of farm approval include maintenance
of the project area, which would include cleaning up unnatural debris.
In summary, with proper farm management, it is unlikely that geoduck aquaculture farming would
result in the creation of macro- or microplastic debris. There is no evidence that existing farms in
Puget Sound are creating plastics debris or resulting in metals leaching into the sediment from the
use of PVC tubes or HDPE materials. Therefore, with proper farm management, no net loss of
ecological function is anticipated from plastics or toxicity.
3.11 Summary of Potential Effects
Although shellfish aquaculture can result in short-term, localized changes, overall there is a
potential net gain, or at worst, insignificant effect, as demonstrated above. Table 3 is a summary of
potential direct effects for each parameter discussed above.
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Table 3 Summary of Potential Effects from Geoduck Aquaculture
Parameter Potential Effect Duration Level of Effect
Noise
Airborne Noise: minor increase
above background when boats or
pump motors are in use
Underwater Noise: minor
increase above background
when boats motors are in use
Airborne Noise: during
transit (boat motor) and
during harvest (pump)
Underwater Noise:
during transit
Airborne Noise: insignificant
Underwater Noise:
insignificant
Water Quality
Filtration: increased water clarity
locally by reducing plankton
blooms and nutrients
Harvest: increased suspended
sediments and nutrients
Fish Behavior: avoidance or
increased foraging
Filtration: during grow-
out
Harvest: during harvest
and for about 1-2 tidal
cycles
Fish Behavior: during
harvest
Filtration: beneficial (albeit
small)
Harvest: insignificant
Fish Behavior: insignificant to
beneficial
Sediment Quality
Sediment quality: increased
density of geoducks can result in
increased organic content, .
Sediment quality: when
mush tubes are in place
(maximum of 2 years)
Sediment quality:
insignificant
Sediment
Transport and
Bathymetry
Tubes: minor accretion of
sediments within the tube area
Harvesting: changes to elevation
and grain size
Tubes: 2 years of grow-
out cycle; baseline
conditions within 1-2 tidal
cycles
Harvesting: 1-4 months
Tubes:
insignificant
Harvesting: insignificant
Migration,
Access, and
Refugia
Tubes: the vertical relief (4-5
inches) is different than sandflat
habitat
Tubes: when tubes are
present
(2 years)
Tubes:
insignificant
Forage Fish
Spawning: potential overlap with
forage fish spawning habitat;
largely avoided with spatial
separation and conservation
measures
Sediment mobilization: sediment
migrates to spawning beds;
unlikely with wave energy
Larvae ingestion: forage fish
larvae ingested by geoduck filter
feeding; unlikely based on size
Spawning: planting,
maintenance, and
harvest
Sediment mobilization:
harvest
Larvae ingestion: grow-
out (5-7 years)
Spawning: insignificant
Sediment mobilization:
insignificant
Larvae ingestion:
insignificant
Benthic Infauna
and Epifauna
Benthic fauna: potential increase
of prey, but also short-term
change of community structure
Benthic fauna: baseline
conditions within several
months; 6 months post-
harvest
Benthic fauna: insignificant
Waterfowl
Beneficial effect due to increased
forage on culture tubes
Potential displacement of
foraging or loafing birds.
1-2 years of 5-7 year
cycle.
Beneficial Foraging:
Potentially significant
beneficial effect.
Displacement: Insignificant
since sandy habitat of farm is
not prime foraging habitat for
waterfowl. Also, PVC tubes
will not preclude use of
farmed area by waterfowl
and/or shorebirds.
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Parameter Potential Effect Duration Level of Effect
Aquatic
Vegetation
Eelgrass and Attached Kelp:
none present in project area
Macroalgae: drift macroalgae
would be disturbed, but not taken
out of the system
Eelgrass and attached
kelp: not applicable
Macroalgae: planting,
maintenance, and
harvest activities
Eelgrass and attached kelp:
not applicable
Macroalgae: insignificant
Plastics and
Toxicity
Macroplastic debris
Microplastic debris
Toxic leachates
1-2 years of 5-7 year
cycle.
Macroplastic debris:
Insignificant with farm
management plan
Microplastic debris:
Insignificant with use of
HDPE
Toxic leachates: Insignificant
with use of HDPE
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