[Federal Register Volume 77, Number 175 (Monday, September 10, 2012)]
[Proposed Rules]
[Pages 55645-55679]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-22092]
[[Page 55645]]
Vol. 77
Monday,
No. 175
September 10, 2012
Part IV
Department of Commerce
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National Oceanic and Atmospheric Administration
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50 CFR Part 217
Taking and Importing Marine Mammals; Taking Marine Mammals Incidental
to Construction and Operation of a Liquefied Natural Gas Deepwater Port
in the Gulf of Mexico; Proposed Rule
Federal Register / Vol. 77 , No. 175 / Monday, September 10, 2012 /
Proposed Rules
[[Page 55646]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 110801452-2387-03]
RIN 0648-BB00
Taking and Importing Marine Mammals; Taking Marine Mammals
Incidental to Construction and Operation of a Liquefied Natural Gas
Deepwater Port in the Gulf of Mexico
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
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SUMMARY: NMFS has received a request from Port Dolphin Energy LLC (Port
Dolphin) for authorization to take marine mammals incidental to port
construction and operations at its Port Dolphin Deepwater Port in the
Gulf of Mexico, over the course of five years; approximately June 2013
through May 2018. Pursuant to the Marine Mammal Protection Act (MMPA),
NMFS is proposing regulations to govern that take and requests
information, suggestions, and comments on these proposed regulations.
DATES: Comments and information must be received no later than October
25, 2012.
ADDRESSES: You may submit comments on this document, identified by FDMS
Docket Number 110801452-2387-03, by any of the following methods:
Electronic Submission: Submit all electronic public
comments via the Federal e-Rulemaking Portal www.regulations.gov. To
submit comments via the e-Rulemaking Portal, first click the Submit a
Comment icon, and then enter 110801452-2387-03 in the keyword search.
Locate the document you wish to comment on from the resulting list and
click on the Submit a Comment icon on the right of that line.
Hand delivery or mailing of comments via paper or disc
should be addressed to Michael Payne, Chief, Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service, 1315 East-West Highway, Silver Spring, MD 20910.
Comments regarding any aspect of the collection of information
requirement contained in this proposed rule should be sent to NMFS via
one of the means provided here and to the Office of Information and
Regulatory Affairs, NEOB-10202, Office of Management and Budget, Attn:
Desk Office, Washington, DC 20503, OIRA@omb.eop.gov.
Instructions: Comments must be submitted by one of the above
methods to ensure that the comments are received, documented, and
considered by NMFS. Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered. All comments received are a part of the public
record and will generally be posted for public viewing on
www.regulations.gov without change. All personal identifying
information (e.g., name, address) submitted voluntarily by the sender
will be publicly accessible. Do not submit confidential business
information, or otherwise sensitive or protected information. NMFS will
accept anonymous comments (enter N/A in the required fields if you wish
to remain anonymous). Attachments to electronic comments will be
accepted in Microsoft Word, Excel, or Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
A copy of Port Dolphin's application may be obtained by writing to
the address specified above (see ADDRESSES), calling the contact listed
above (see FOR FURTHER INFORMATION CONTACT), or visiting the Internet
at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. To help NMFS
process and review comments more efficiently, please use only one
method to submit comments.
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103
as ``* * * an impact resulting from the specified activity that cannot
be reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.''
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as: ``any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild [`Level A harassment']; or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering [`Level B harassment'].''
Summary of Request
On February 1, 2011, NMFS received a complete application from Port
Dolphin for the taking of marine mammals incidental to port
construction and operations at its Port Dolphin Deepwater Port (DWP)
facility in the Gulf of Mexico (GOM). During the period of these
proposed regulations (June 2013-May 2018), Port Dolphin proposes to
construct the DWP and related infrastructure--expected to occur over an
approximately 11-month period, beginning in June 2013--and to
subsequently begin operations. The proposed DWP, which is designed to
have an operational life expectancy of 25 years, would be an offshore
liquefied natural gas (LNG) facility, located in the GOM approximately
45 km (28 mi) off the western coast of Florida, and approximately 68 km
(42 mi) from Port Manatee, located in Manatee County, Florida, within
Tampa Bay (see Figure S-1 in Port Dolphin's application). The DWP would
be in waters of the U.S. Exclusive Economic Zone (EEZ) approximately 31
m (100 ft) in depth. The proposed DWP would consist principally of a
permanently moored buoy system, designed for offloading of natural gas,
leading to a single proposed new natural gas transmission pipeline that
would come ashore at Port Manatee and connect to existing
infrastructure.
Take of marine mammals would occur as a result of the introduction
of sound into the marine environment during construction of the DWP and
pipeline and during DWP operations, which would involve shuttle
regasification
[[Page 55647]]
vessel (SRV) maneuvering, docking, and debarkation, as well as
regasification activity. Because the specified activities have the
potential to take marine mammals present within the action area, Port
Dolphin requests authorization to incidentally take, by Level B
harassment only, small numbers of bottlenose dolphin (Tursiops
truncatus) and Atlantic spotted dolphin (Stenella frontalis).
Description of the Specified Activity
Port Dolphin proposes to own, construct, and operate a DWP in the
U.S. EEZ of the GOM Outer Continental Shelf (OCS) approximately 45 km
(28 mi) off the western coast of Florida to the southwest of Tampa Bay,
in a water depth of approximately 31 m (100 ft). On March 29, 2007,
Port Dolphin submitted an application to the U.S. Coast Guard (USCG)
and the U.S. Maritime Administration (MarAd) for all federal
authorizations required for a DWP license under the Deepwater Port Act
of 1974 (DWPA). Port Dolphin received that license in October 2009. The
Port would consist of a permanently moored unloading buoy system with
two submersible buoys separated by a distance of approximately 5 km (3
mi). The buoys would be designed to moor a specialized type of LNG
carrier vessel (i.e., SRVs) and would remain submerged when vessels are
not present. Regasified natural gas would be sent out through the
unloading buoy to a 36-in (0.9 m) pipeline that would connect onshore
at Port Manatee with the existing Gulfstream Natural Gas System and
Tampa Electric Company (TECO) Bayside pipeline. The DWP would only
serve SRVs. Construction of the DWP would be expected to take 11
months. Port Dolphin DWP would be designed, constructed, and operated
in accordance with applicable codes and standards and would have an
expected operating life of approximately 25 years. The locations of the
DWP and associated pipeline are shown in Figure S-1 in Port Dolphin's
application; Figure 1-1 of the same document depicts a conceptual site
plan for the DWP.
The installation of the DWP facilities would include the
construction and installation of offshore buoys, mooring lines, and
anchors. The two unloading buoys, also known as submerged turret
loading (STL) buoys, would each have eight mooring lines connected to
anchor points, likely consisting of piles driven into the seabed. When
not connected to a SRV, STL buoys would be submerged 60 to 70 ft (18 to
21 m) below the sea surface. The installation of the pipeline from the
DWP to shore would include burial of the pipeline, selective placement
of protective cover (either rock armoring or concrete mattresses) over
the pipeline at several locations along the pipeline route where full
burial is not possible, and the horizontal directional drilling (HDD)
of three segments of the pipeline.
SRVs are specialized LNG carriers designed to regasify the LNG
prior to off-loading for transport to shore. Each STL buoy would moor
one SRV on location throughout the unloading cycle. An SRV would
typically moor at the deepwater port for between 4 and 8 days,
depending on vessel size and send-out rate. Unloading of natural gas
(i.e., vaporization or regasification) would occur through a flexible
riser connected to the STL buoy and into the pipeline end manifold
(PLEM) for transportation to shore via the subsea pipeline. With two
separate STL buoys, Port Dolphin may schedule an overlap between
arriving and departing SRVs, thus allowing natural gas to be delivered
in a continuous flow.
Port Dolphin is planning for an initial natural gas throughput of
400 million standard cubic feet per day (MMscfd). Although the Port
would be capable of an average of 800 MMscfd with a peak capacity of
1,200 MMscfd, this level of throughput would not be achieved during the
span of this proposed rule. Based on a regasification cycle of
approximately 8 days and initial throughput of 400 MMscfd, maximum
vessel traffic during operations over the lifetime of the proposed 5-
year regulations is projected to consist of 46 SRV unloadings per year.
In the open ocean, SRVs typically travel at speeds of up to 19.5 kn
(36.1 km/hr). When approaching the vicinity of the DWP (i.e., during
approach to the DWP), the SRVs would typically slow to about half
speed. In close proximity to the STL buoys, the SRVs would slow to dead
slow and utilize thrusters to attain proper vessel orientation relative
to the DWP, taking into consideration ambient ocean currents, wind
conditions, and buoy position. The following subsections describe the
Region of Activity and the preceding facets of construction and
operation in greater detail.
Region of Activity
The GOM is a marine water body bounded by Cuba on the southeast;
Mexico on the south and southwest; and the U.S. Gulf Coast on the west,
north, and east. The GOM has a total area of 564,000 km\2\ (217,762
mi\2\). Shallow and intertidal areas (water depths of less than 20 m)
compose 38 percent of the total area, with continental shelf (22
percent), continental slope (20 percent), and abyssal plain (20
percent) composing the remainder of the basin. The project site is
located on the west Florida Shelf, a portion of the Inner Continental
Shelf, in an area of relatively low wave energy and tidal variation
(Gore, 1992).
The GOM is separated from the Caribbean Sea and Atlantic Ocean by
Cuba and other islands, and has relatively narrow connections to the
Caribbean and Atlantic through the Florida and Yucatan Straits. The GOM
is composed of three distinct water masses, including the North and
South Atlantic Surface Water (less than 100 m deep), Atlantic and
Caribbean Subtropical Water (up to 500 m deep), and Subantarctic
Intermediate Water.
Circulation within the GOM, and within the project area, is
dominated by the Loop Current, which enters the GOM flowing north
through the Yucatan Strait, flows south along the Florida coast in the
vicinity of the project area, and exits the GOM through the Florida
Straits. The velocity of the current in the project area ranges between
1.56 and 15.16 cm/s in summer, and 1.79 to 25.36 cm/s in winter (APL,
2006). The direction of flow in the project area is generally south to
southeast.
In shallow areas along the west Florida Shelf, additional
influences on water flow and circulation include wind stress,
freshwater inflow, and variations in buoyancy (Gore, 1992). Wind speeds
at the project site range from 2.26 to 7.61 m/s in summer, and 2.85 to
11.04 m/s in winter (APL, 2006). Tidal variation along Florida's west-
central continental shelf is moderate, with an average range of
approximately 2 ft (0.6 m) (Gore, 1992).
At the eastern edge of the Loop Current along the west Florida
Shelf, circulation patterns result in an upwelling of deep nutrient-
rich water. This upwelling supports a high level of biological
activity, producing large concentrations of plankton. Nutrient levels
(primarily nitrogen and phosphorus) are also affected by runoff from
agricultural and urbanized areas and from submarine groundwater
discharge, leading to red tide conditions. In the project area, red
tide occurs on an almost annual basis (Hu et al., 2006). Red tides are
caused by rapid growth of the species Karenia brevis, a toxic species
which produces brevetoxins (a type of neurotoxin) that can accumulate
in bivalves and cause mortality in marine organisms (Hu et al., 2006).
The rapid growth of these organisms can also create a hypoxic zone
(area with dissolved oxygen
[[Page 55648]]
concentrations below 2 mg/L), which can cause mortality among benthic
communities, fish, turtles, birds, and marine mammals (Hu et al.,
2006).
Extreme variations in water circulation patterns, tides, and wave
heights can occur along the west Florida coast during periodic tropical
storms and hurricanes. Warm water within the Loop Current can act as an
energy source in summer and fall months, fueling the development of
these storms. Features of these storms that can affect natural
circulation and topography include high winds, flooding, storm surges,
and beach erosion.
Tampa Bay is an estuary formed by the rise of sea level into a
former river valley. Tampa Bay consists of four subregions, including
lower Tampa Bay, middle Tampa Bay, Old Tampa Bay, and Hillsborough Bay.
The project area would only extend to Port Manatee, within Lower Tampa
Bay, near the outlet of the bay into the GOM. The bay covers an area of
1,030 km\2\ within Hillsborough, Manatee, and Pinellas counties.
Freshwater inflow to the bay occurs through four major river systems
(Alafia, Hillsborough, Little Manatee, and Manatee), as well as more
than a hundred minor creeks and rivers.
Water circulation within the bay is driven by freshwater inflow,
tides, and winds. The bay has an average depth of 3.5 to 4 m. There is
well-developed horizontal stratification in the bay, with fresh water
flowing along the surface out to sea, and denser saline water flowing
into the bay along the bottom.
The Tampa Bay area has a population of more than two million
people, and tributaries, habitat, runoff patterns, and water quality
are all affected by urbanization. Specific actions that have affected
the bay include removal of mangroves, dumping of sewage, artificial
filling, and modification of runoff from paved surfaces (Peene et al.,
1992).
Dates of Activity
Port Dolphin has requested regulations governing the incidental
take of marine mammals for the five-year period from June 2013 through
May 2018. Construction and installation of the port and pipeline would
last approximately 11 months, with subsequent operations (i.e., SRV
docking and regasification) occurring for the remainder of the
specified time period.
LNG and SRVs
The DWPA establishes a licensing system for ownership,
construction, and operation of deepwater ports in waters beyond the
territorial limits of the United States. Originally, the DWPA promoted
the construction and operation of deepwater ports as a safe and
effective means of importing oil into the United States and
transporting oil from the OCS, while minimizing tanker traffic and
associated risks close to shore. The Maritime Transportation Security
Act of 2002 amended the definition of ``deepwater port'' to include
facilities for the importation of natural gas.
LNG is natural gas that has been cooled to about -260 [deg]F (-162
[deg]C) for efficient shipment and storage as a liquid. LNG is more
compact than the gaseous equivalent, with a volumetric differential of
about 610 to 1. LNG can thus be transported long distances across
oceans using specially designed ships (e.g., SRVs), allowing efficient
access to stranded reserves of natural gas that cannot be transported
by conventional pipelines.
This proposed STL buoy system differs from other common LNG offload
technologies insofar as it does not involve any permanent storage or
regasification facility at the DWP, thus minimizing required
infrastructure at the DWP itself. Rather, STL buoys receive SRVs that
contain onboard LNG vaporization equipment. After mooring, LNG is
vaporized onboard the vessel and discharged via the unloading buoy and
a flexible riser into the subsea pipeline. Because the LNG is vaporized
with the SRV's onboard equipment, no permanent fixed or floating
storage or vaporization facilities are required. However, this means
that the offload process can take 5 to 8 days, as compared with a
standard offload of 18 hours or less. As a result of this trade-off,
continuous off-loading operations are essential to minimize
fluctuations in the throughput of natural gas. The SRVs proposed for
use would be equipped to transport, store, vaporize, and meter natural
gas. A closed-loop, glycol/water-brine heat transfer system would be
used to vaporize the LNG. Closed-loop systems burn vaporized LNG in
order to heat an intermediate fluid (e.g., glycol/water-brine), which
warms the LNG. The closed-loop system results in reduced environmental
impacts on water quality and marine resources; although these systems
do require seawater for use in cooling electrical generating equipment
(resulting in subsequent entrainment of fish eggs and plankton, as well
as discharge of water at elevated temperatures), such usage is
significantly reduced from that required in an open-loop system.
SRVs with approximate cargo capacities of either 145,000 m\3\ or
217,000 m\3\ (189,653-283,825 yd\3\) based on standard designs for
oceangoing LNG carriers would be used to supply LNG to the Port.
Approximate dimensions of each SRV would range from 280 m (919 ft) in
length and 43 m (141 ft) in breadth, with a design draft of 11.4 m
(37.4 ft) for the smaller vessels to 315.5 m (1,035 ft) in length and
50 m (164 ft) in breadth, with a design draft of 12 m (39 ft) for the
larger vessels. The maximum height above the waterline would be 41.1 m
(135 ft). The 145,000 m\3\ SRV would displace 80,000 t (88,185 ton) and
the 217,000 m\3\ SRV would displace 108,000 t (119,050 ton). The
vessels would be equipped with a trunk and mating cone to receive the
unloading buoy, lifting and connection devices, an LNG vaporization
system, and gas metering systems. All critical functions would be
manned 24 hours per day; other functions would be accomplished on a
regular, scheduled basis.
The SRVs would have two thrusters forward and could have one or two
thrusters aft. Thrusters allow precise control of positioning while
mooring with the STL buoy. The dynamic positioning system would be used
while retrieving the submerged unloading buoy handling line and moving
onto the buoy. The system normally would not be used while the SRV is
moored to the unloading buoy. SRVs would be equipped with an acoustic
position reporting system that would monitor the buoy's draft and
position before and during connection/disconnection; this would be
enabled by six transponders located on the buoy itself.
Seawater would be used to ballast the SRV, cool the dual-fuel
diesel engines supplying power for the regasification process, and
condense the steam produced by the boilers supplying heat to the
vaporization process. Ballasting the SRV is required to maintain proper
buoyancy as the LNG is vaporized and offloaded through the pipeline.
Water intake for ballasting the SRV would require an average intake of
360 m\3\ per hour (2.3 MGD) over the vaporization cycle. The cooling
water system would require an additional intake of approximately 1,520
m\3\ per hour (9.5 MGD) and would take in seawater through one of two
sea chests, each measuring 1.5 x 2.0 m (4.9 x 6.6 ft). Water velocity
through the lattice screens at the hull side shell would not exceed
0.15 m/s (0.49 ft/s) at the maximum flow rate of 1,520 m\3\ per hour.
Cooling water discharges would be made at points removed from the
intake sea chests to avoid recirculating warmed water through the
cooling system. All of the cooling water would be discharged
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at a temperature of approximately 10 [deg]C (18 [deg]F) above the
ambient water temperature. Although the seawater system would be
equipped with a chlorination system to prevent biofouling of heat
transfer surfaces and system components, the chlorination system would
not be used while the SRVs are approaching the Port or moored at the
buoys.
Port Construction
In-water construction of Port Dolphin is expected to begin in June
2013 and last a total of approximately 11 months. Construction would
include siting the STL buoys and associated equipment and laying the
marine pipeline. Construction is assumed to be continuous from
mobilization to demobilization with no work stoppages due to weather or
other issues. Please see Table 2-1 of Port Dolphin's application for a
graphical depiction of the complete timeline of proposed construction
activities. Port Dolphin anticipates that construction/installation
would be accomplished in the following sequence:
Install the Port Manatee HDD section, with installation
proceeding from onshore to the offshore location.
Install the anchor piles and the mooring lines using the
main installation vessel at the DWP.
Construction and installation of the HDD pipe sections for
the segments under the existing Gulfstream pipeline.
Install seabed pipe segments between the Port Manatee HDD
segment and the Gulfstream HDD segments.
Install the Skyway Bridge section of the pipe (requiring
dredging through the causeway).
Install the STL Buoys.
Install the two risers from the PLEMs.
Install the north and south PLEMs.
Perform pipelay and diving operations towards the Y-
connector.
Install the flowlines on the seafloor.
Complete tie-ins and bury or armor the pipeline, as
necessary.
Conduct testing of the pipeline upon completion of burial
operations.
These components of in-water construction are discussed in greater
detail in the following subsections.
DWP Construction/Installation--As described previously, the Port
would include two STL unloading buoy systems, separated by a distance
of approximately 5 km (3.1 mi) in a water depth of approximately 31 m
(100 ft). Each unloading buoy would have eight mooring lines,
consisting of wire rope and chain, connecting to eight driven-pile
anchor points on the sea floor, one 16-in (0.4-m) inside diameter
flexible pipe riser, and one electrohydraulic control umbilical from
the unloading buoy to the riser manifold. When not connected to a SRV,
STL buoys would be submerged 60 to 70 ft (18 to 21 m) below the sea
surface. A concrete or steel landing pad would be fixed to the sea
floor by means of a skirted mud mat to allow lowering of the STL buoy
to the ocean floor when it is not in use.
The mooring lines would be designed so that the SRV could remain
moored in non-hurricane 100-year storm conditions, and would vary in
length, from 1,800 to 4,000 ft (549 to 1,219 m) for the northern
unloading buoy and from 2,500 to 3,600 ft (762 to 1,097 m) for the
southern buoy. The mooring lines would consist of 132-mm (5.2-in) chain
and 120-mm (4.7-in) spiral-strand wire rope. The riser system for each
unloading buoy would consist of one 16-in interior diameter flexible
riser in a steep-wave configuration. Total length of the riser would be
approximately 82 m (269 ft). The riser would be directed between two of
the mooring lines, and would lie on the seafloor when not in use.
The two PLEMs near the unloading buoys would connect the flexible
risers to the flowlines and a Y-connection that would connect the two
flowlines to the new gas transmission pipeline. Each of the two PLEMs
would be approximately 75 m (246 ft) offset from the proposed unloading
buoy locations. The purpose of a PLEM is to provide an interface
between the pipeline system and the flexible riser, isolate the riser
between gas unloading operations, and attach a subsea pig launcher or
receiver as necessary. ``Pigs,'' or ``pipeline inspection gauges,''
travel remotely through a pipeline to conduct inspections of or clean
the pipeline and collect data about conditions in the pipeline. Each
PLEM would include a flange connection for attaching the flexible riser
or the subsea pig launcher/receiver and a full-bore subsea hydraulic
control valve and electrohydraulic umbilical termination assembly. Each
PLEM would have a mud mat foundation to provide a stable base for
bearing PLEM and riser weight and to resist sliding and overturning
forces. Please see Figure 1-1 in Port Dolphin's application for a
conceptual diagram of the DWP.
Offshore installation activities at the DWP would begin with
installation of the PLEMs at both STL buoy locations (north and south),
followed by placement of the buoy anchors, mooring lines, buoys, and
risers. Installation activities at both STL buoy locations would
require a cargo barge, supported by anchor-handling support vessels, a
supply boat, a crew transfer boat, and a tug. Buoy anchors would likely
be installed via impact pile driving.
Pipeline Installation--The pipeline would be laid on the seafloor
by a pipelaying barge and then buried, typically using a plowing
technique. Other techniques, such as dredging and HDD, are planned to
be used in certain areas depending on the final geotechnical survey,
engineering considerations, and equipment selection. At the western
(seaward) end, the pipeline would consist of two 36-in (0.9-m)
flowlines connected to the north and south PLEMs, which would connect
at a Y-connection approximately 3.2 km (2 mi) away (see Figure 1-1 in
Port Dolphin's application). From the Y-connection a 36-in (0.9-m) gas
transmission line would travel approximately 74 km (46 mi) to
interconnections with the Gulfstream and TECO pipeline systems. The
pipelines would have a nominal outer diameter of 36 in, with a coating
of fusion-bonded epoxy and a concrete weight coating thickness of 11.4
cm (4.5 in).
Pipeline trenching and burial requirements are governed by
Department of the Interior regulations at 30 CFR 250 Subpart J, which
requires pipelines and all related appurtenances to be protected by 3
ft (0.9 m) of cover for all portions in water depths less than 200 ft
(61 m). Portions of the pipeline that travel through hard-bottom areas
may not be able to be buried to the full 3 ft depth. In these areas,
flexible concrete mattresses or other cover would be used to cover the
pipeline. In places where the pipeline crosses shipping lanes, it would
be buried 10 ft (3 m) deep if the sea floor permits plowing. Burying
the pipeline and flowlines would protect them from potential damage
from anchors and trawls and avoid potential fouling, loss, or damage of
fishermen's trawls. The pipeline construction corridor would be 3,000
ft (914 m) wide in offshore areas. The permanent in-water right-of-way
for the pipeline would be 200 ft (61 m) wide.
Under the plowing method, the pipeline is lowered below seabed
level by shearing a V-shaped ditch underneath it. The plow is towed
along and underneath the pipeline by the burial barge. As the ditch is
cut, sediment is removed and passively pushed to the side by specially
shaped moldboards that are fitted to the main plowshare. The trench is
then backfilled with a subsequent pass of the plow. The estimated width
of the trench (including sediments initially pushed to each side) is 67
ft (20.4 m) (see Figure 1-2 in Port
[[Page 55650]]
Dolphin's application for a conceptual diagram of this process).
In areas that cannot be plowed (e.g., due to hard/live bottom) or
complete burial cannot be achieved, the pipeline would be covered with
an external cover (e.g., concrete mattresses or rock armoring).
Although plowing is the preferred methodology for pipeline burial,
other techniques such as dredging and HDD would be used where required.
Figure 1-3 of Port Dolphin's application uses color coding of the
proposed pipeline route to show where these various methodologies would
be used, based on bottom structure and other barriers. The total length
of the pipeline route is 74 km. Burial techniques to be used along the
pipeline route and their relative lengths are characterized as follows:
Plowing/trenching soft sediments: 39.6 km (24.6 mi; 53.2
percent of total pipeline length);
Plowing/external cover: 23.3 km (14.5 mi; 31.4 percent);
External cover (concrete mattress/rock armoring): 8.5 km
(5.3 mi; 11.7 percent);
Clamshell dredging/dragline burial: 0.3 km (0.2 mi; 0.5
percent); and
HDD: 2.4 km (1.5 mi; 3.2 percent).
HDD would be employed for installation of the pipeline at three
locations along the inshore portion of the route. The proposed HDD
locations include drilling from land to water at the Port Manatee shore
approach and from water-to-water at two crossings of the existing
Gulfstream pipeline. The eastern HDD crossing would be 898 m (2,947 ft)
in length, and the western HDD crossing would be 407 m (1,335 ft) in
length. Both crossings would be in a water depth of 6.4 m (21 ft). The
Port Dolphin pipeline would be drilled to a depth of approximately 6 m
(20 ft) below the existing Gulfstream Pipeline (Port Dolphin, 2007b).
HDD is a steerable method of installing pipelines underground along
a prescribed bore path, with minimal impact on the surrounding area.
The process starts with location of entry and exit points. The first
stage drills a pilot hole on the designed path, and the second stage
enlarges the hole by passing a larger cutting tool known as a reamer.
This would involve using progressively larger drill strings to
eventually produce a drill bore 48 in (1.22 m) in diameter. The third
stage places the product or casing pipe in the enlarged hole by way of
the drill steel and is pulled behind the reamer to allow centering of
the pipe in the newly reamed path. Simultaneously, bucket dredging
would be employed to produce an exit hole at the end of the bore. In-
water HDD may involve significant distance between the seabed and the
drilling rig, and so a casing pipe may be required during the initial
pilot hole drilling to provide some rigidity to the drill pipe as it is
pushed ahead by the rig. Structures known as ``goal posts'' provide
support for the casing pipe and are typically comprised of two driven
piles with cross members set at predetermined elevations.
Port Dolphin has identified the need to install goal posts as part
of the HDD drilling effort at the two water-to-water HDD locations. One
potential option is that the goal posts are designed to self-install;
however, another option is that drilling may be required. Further, at
the shore-to-water transition HDD, Port Dolphin would need to install
sheet piling to form a coffer dam, designed to contain the HDD exit pit
so as to not impact nearby aquatic vegetation. Sheet pile segments
would be installed by vibratory means.
Clam shell dredging would be required for passage under the Skyway
Bridge and would be performed from a fixed working platform. Although
dredging, followed by conventional lay and bury, is the most likely
scenario, HDD remains a possibility for this segment. In the area near
Manbirtee Key, a flotation ditch--dredging operations may require such
a ditch when the minimum water depth necessary to safely float
equipment is not present--would be dredged using conventional dredging
equipment (i.e., the same barge that would be used to pull-in the shore
approach HDD). The anticipated locations where the various methods of
pipeline installation would be used are shown in Figure 1-3 of Port
Dolphin's application.
There are eleven locations where tie-in operations would be
required to piece the pipeline sections together. This mechanical
operation is accomplished with specially designed connectors and a
manned diving rig. This common operation does not require welding. Tie-
ins would be required at each end of all HDD crossings, the Y-
connection, and the PLEMs.
Construction Vessels--A shallow-water lay barge, spud barge and
clamshell dredge, and a jack-up barge would be mobilized for offshore
pipe-laying activities. Jack-up barges are mobile work platforms that
are fitted with long support legs that can be raised or lowered; upon
arrival at the work location the legs would be lowered and the barge
itself raised above the water such that wave, tidal and current loading
acts only on the relatively slender legs and not on the barge hull. A
spud barge is a type of jack-up barge that typically offers increased
stability but does not raise the hull above the water. This equipment
would be used where conventional installation methods are anticipated.
An HDD spread, including four jack-up barges, three hopper barges
(designed to carry materials), and two tugs for barge towing, would be
used for the three planned HDD segments. Four diving support vessels
would also support tie-in and mattressing operations. Construction
equipment would make one round-trip to the project location, staying on
location for the duration of construction activity. Work crew vessels
and supply vessels would make on average two trips a day for the
duration of offshore construction. Work crew and supply vessels are
expected to make between 420 and 450 round-trips to the offshore
construction location from shore-based facilities for the duration of
the project.
Table 1 details the vessels that would be used during the DWP and
pipeline construction and installation activities. The projected
duration and duty load of each vessel are also provided. Duty load is a
primary consideration when characterizing project-related sound
sources.
Table 1--Vessels To Be Employed During Port Dolphin Construction and/or Facility Installation Operations
----------------------------------------------------------------------------------------------------------------
Engine specifications
Operation Auxiliary equipment/notes \1\ Operational usage \2\
----------------------------------------------------------------------------------------------------------------
Construction/Installation at DWP
----------------------------------------------------------------------------------------------------------------
Barge.............................. ........................... N/A................... 3.5 months at 100%.
Anchor-handling support vessels.... ROV winches, hydraulic 2 x 3,750-hp..........
pumps, thrusters, sonar,
survey equipment.
Supply boat........................ Bow thruster............... 671-hp................
[[Page 55651]]
Crew transfer boat................. ........................... 671-hp................
Tug................................ ........................... 800-hp................
Impact hammer...................... ........................... N/A................... As required.
----------------------------------------------------------------------------------------------------------------
Pipeline installation
----------------------------------------------------------------------------------------------------------------
Jack-up: Port Manatee HDD.......... Jack-up.................... 3,000-hp.............. 27 days at 50%.
Spud lay barge: Shallow lay Tug........................ 1,200-hp.............. 59.4 days at 75%.
operation; no propulsion; uses two
tugs.
Tug........................ 1,200-hp..............
East jack-ups...................... Jack-up.................... 3,000-hp.............. 27 days at 75%.
Jack-up.................... 3,000-hp..............
West jack-ups...................... Jack-up.................... 3,000-hp.............. 27 days at 75%.
Jack-up.................... 3,000-hp..............
Pipelay barge: Large lay barge Tug........................ 2,000-hp.............. 37 days at 85%.
operation; no propulsion; uses two
tugs.
Tug........................ 2,000-hp..............
Dragline barge..................... ........................... 600-hp................ 6 days at 100%.
Plow lay barge: Plow burial Tug........................ 2,000-hp.............. 113 days at 85%.
operation; no propulsion; uses two
tugs.
Tug........................ 2,000-hp..............
DSVs for mattress armoring......... Vessel..................... 1,000-hp.............. 108 days at 100%.
Vessel..................... 1,000-hp..............
DSVs for mattress armoring......... Vessel..................... 1,000-hp.............. 12 days at 15%.
........................... 1,000-hp..............
Vessel..................... 1,000-hp..............
........................... 1,000-hp..............
Pipeline gauge, fill, test, Vessel..................... 300-hp................ 13 days at 35%.
dewater, and drying.
........................... 300-hp................
Vessel..................... 300-hp................
........................... 300-hp................
Survey vessel...................... Vessel..................... 1,000-hp.............. 54 days at 50%.
Vessel..................... 1,000-hp..............
Spud lay barge: Shallow lay barge Tug........................ 1,200-hp.............. 6.6 days at 15%.
operation; no propulsion; uses two
tugs.
Tug........................ 1,200-hp..............
East jack-ups...................... Jack-up.................... 2,000-hp.............. 3 days at 15%.
Jack-up.................... 2,000-hp..............
West jack-ups...................... Jack-up.................... 2,000-hp.............. 3 days at 15%.
Jack-up.................... 2,000-hp..............
Pipelay barge: Large lay barge Tug........................ 2,000-hp.............. 4 days at 15%.
operation; no propulsion; uses two
tugs.
Tug........................ 2,000-hp..............
Dragline barge..................... Barge...................... 600-hp................ 1 day at 15%.
Plow lay barge: Plow burial Tug........................ 2,000-hp.............. 13 days at 15%.
operation; no propulsion; uses two
tugs.
Tug........................ 2,000-hp..............
DSVs for mattress armoring......... Vessel..................... 1,000-hp.............. 12 days at 15%.
........................... 1,000-hp..............
Vessel..................... 1,000-hp..............
........................... 1,000-hp..............
Pipeline gauge, fill, test, Vessel..................... 300-hp................ 1 day at 15%.
dewater, and drying.
........................... 300-hp................
Vessel..................... 300-hp................
........................... 300-hp................
Survey vessel...................... Vessel..................... 1,000-hp.............. 6 days at 15%.
----------------------------------------------------------------------------------------------------------------
HDD operations
----------------------------------------------------------------------------------------------------------------
Jack-up: Port Manatee HDD.......... Jack-up.................... 3,000-hp.............. 3 days at 15%.
Spud barge......................... Crane-mounted drill and N/A................... Maximum 4 days for
vibratory drill; ancillary vibratory drilling at
equipment includes welding each HDD location.
equipment, air compressor,
and generator.
Tug................................ ........................... 800-hp................ Maximum 4 days for
vibratory drilling at
each HDD location.
----------------------------------------------------------------------------------------------------------------
DSV = Diving spread vessels
\1\ All specifications are for diesel engines.
\2\ All figures assume 24 hrs/day; percentages refer to percent maximum duty load.
[[Page 55652]]
Port Operations
The proposed DWP operations would include SRV maneuvering/docking,
regasification of LNG cargo, and debarkation. The SRVs are expected to
approach the DWP from the south. In the open ocean, the SRVs typically
travel at speeds of up to 19.5 kn (36.1 km/hr), reducing to less than
14 kn (25.9 km/hr) while maintaining full maneuvering speed. However,
once approaching the vicinity of the DWP--within approximately 16 to 25
km (10-16 mi) of the DWP--the SRVs would begin approach by slowing to
about half speed, and then to slow ahead. Inside of 5 km (3.1 km) from
the DWP, the SRVs' main engines would be placed in dead slow ahead and
decreased upon approach to dead slow, with final positioning and
docking to occur using thrusters. Expected SRV transit, approach, and
maneuvering/docking characteristics are outlined in Table 2. Only the
maneuvering/docking activities and their associated sound sources
(i.e., thrusters) are considered in this document; transit and approach
maneuvers are considered part of routine vessel transit and are not
considered further.
Table 2--SRV Speeds and Thruster Use During Transit, Approach, and
Maneuvering/Docking Operations at the DWP
------------------------------------------------------------------------
Zone Speed limit Thrusters in use?
------------------------------------------------------------------------
>33 km from DWP................. Full service speed No
(19.5 kn).
25-33 km from DWP............... Full maneuvering No
speed (<14 kn).
16-25 km from DWP............... Half ahead (<10 No
kn).
5-16 km from DWP................ Slow ahead (<6 kn) No
Inside 5 km from DWP............ Dead slow ahead Bow and stern
(<4.5 kn, thrusters
decreasing to <3
kn).
Docking......................... Dead slow......... Two bow thrusters;
possibly one or
two stern
thrusters
------------------------------------------------------------------------
Based on a regasification cycle of approximately 8 days and
projected DWP throughput during the first several years of 400 MMscfd,
vessel traffic during operations is projected to consist of a maximum
of 46 SRV trips per year. During DWP operations, sound would be
generated by the maneuvering of SRVs upon approach to the Port,
regasification of LNG aboard the SRVs, and subsequent debarkation from
the Port.
Once an SRV is connected to a buoy, the vaporization of LNG and
send-out of natural gas can begin. Each SRV would be equipped with up
to five vaporization units, each with the capacity to vaporize 250
MMscfd. Under normal operation, two or more units would be in service
simultaneously, with at least one unit on standby mode.
Method of Incidental Taking
Incidental take is anticipated to result from elevated levels of
sound introduced into the marine environment by the construction and
operation of the DWP, as described in preceding sections. Specifically,
sound from pile driving, drilling, dredging, and vessel operations
during the construction and installation phase, and sound from SRV
maneuvering, docking, and regasification during operations would likely
result in the behavioral harassment of marine mammals present in the
vicinity. Table 3 shows these proposed activities by the time of year
they are anticipated to occur.
Table 3--Projected Construction, Installation, and Operations
Activities, by Season
------------------------------------------------------------------------
Activity Season
------------------------------------------------------------------------
Construction and installation
------------------------------------------------------------------------
Buoy installation......................... Summer 2013
Offshore impact hammering................. Summer 2013
Pipelaying offshore....................... Late Summer 2013 through
early Winter 2013-14
Pipelaying inshore........................ Late Summer 2013 through
early Winter 2013-14
Offshore pipeline burial.................. Fall 2013 through Winter
2013-14
Inshore pipeline burial................... Fall 2013 through Winter
2013-14
HDD....................................... Summer 2013
HDD vibratory driving..................... Summer 2013
------------------------------------------------------------------------
Operations
------------------------------------------------------------------------
SRV maneuvering/docking................... Year-round; maximum 46
visits per year
Regasification............................ Year-round; 8 days estimated
per visit
------------------------------------------------------------------------
During construction, underwater sound would be produced by
construction vessels (e.g., barges, tugboats, and supply/service
vessels) and machinery (e.g., pile driving and pipe laying equipment,
trenching equipment, and goal post installation equipment at the HDD
locations) operating either intermittently or continuously throughout
the area during the construction period. Vessel traffic associated with
construction would be a relatively continuous sound source during the
construction phase. Vessel sound would be created by propulsion
machinery, thrusters, generators, and hull vibrations and would vary
with vessel and engine size. Machinery sound from underwater
construction would be transmitted through water and would vary in
duration and intensity. Port construction (i.e., field construction and
installation operations) would require approximately 11 months.
While the main sound source during SRV transit and approach to the
DWP would originate from the SRV main engines (i.e., predominantly in
low frequencies), the primary sound source during maneuvering and
docking would be the SRV thrusters. An additional underwater sound
source would be the sound produced by the flow of gas through the
proposed pipeline, although very little sound would be expected to
result (JASCO, 2008); therefore, this source is not considered further.
Description of Sound Sources
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks of a sound wave; lower frequency sounds have
longer wavelengths than higher frequency sounds, which is why the lower
frequency sound associated with the proposed activities would attenuate
more rapidly in shallower water. Amplitude is the height of the sound
pressure wave or the ``loudness'' of a sound and is typically measured
using the decibel (dB) scale. A dB is the ratio
[[Page 55653]]
between a measured pressure (with sound) and a reference pressure
(sound at a constant pressure, established by scientific standards),
and is a logarithmic unit that accounts for large variations in
amplitude; therefore, relatively small changes in dB ratings correspond
to large changes in sound pressure. When referring to sound pressure
levels (SPLs; the sound force per unit area), sound is referenced in
the context of underwater sound pressure to 1 microPascal ([mu]Pa). One
pascal is the pressure resulting from a force of one newton exerted
over an area of one square meter. The source level (SL) represents the
sound level at a distance of 1 m from the source (referenced to 1
[mu]Pa). The received level is the sound level at the listener's
position.
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Rms is calculated by squaring all of the
sound amplitudes, averaging the squares, and then taking the square
root of the average (Urick, 1975). Rms accounts for both positive and
negative values; squaring the pressures makes all values positive so
that they may be accounted for in the summation of pressure levels
(Hastings and Popper, 2005). This measurement is often used in the
context of discussing behavioral effects, in part because behavioral
effects, which often result from auditory cues, may be better expressed
through averaged units than by peak pressures.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in all
directions away from the source (similar to ripples on the surface of a
pond), except in cases where the source is directional. The
compressions and decompressions associated with sound waves are
detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
The underwater acoustic environment consists of ambient sound,
defined as environmental background sound levels lacking a single
source or point (Richardson et al., 1995). The ambient underwater sound
level of a region is defined by the total acoustical energy being
generated by known and unknown sources, including sounds from both
natural and anthropogenic sources. These sources may include physical
(e.g., waves, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
Even in the absence of anthropogenic sound, the sea is typically a loud
environment. A number of sources of sound are likely to occur within
Tampa Bay and the adjoining shelf, including the following (Richardson
et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient sound for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf sound becomes
important near shore, with measurements collected at a distance of 8.5
km (5.3 mi) from shore showing an increase of 10 dB in the 100 to 700
Hz band during heavy surf conditions.
Precipitation sound: Sound from rain and hail impacting
the water surface can become an important component of total sound at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological sound: Marine mammals can contribute
significantly to ambient sound levels, as can some fish and shrimp. The
frequency band for biological contributions is from approximately 12 Hz
to over 100 kHz.
Anthropogenic sound: Sources of ambient sound related to
human activity include transportation (surface vessels and aircraft),
dredging and construction, oil and gas drilling and production, seismic
surveys, sonar, explosions, and ocean acoustic studies (Richardson et
al., 1995). Shipping sound typically dominates the total ambient sound
for frequencies between 20 and 300 Hz. In general, the frequencies of
anthropogenic sounds are below 1 kHz and, if higher frequency sound
levels are created, they would attenuate (decrease) rapidly (Richardson
et al., 1995). Typical SPLs for various types of ships are presented in
Table 4.
Table 4--Underwater SPLs for Representative Vessels
----------------------------------------------------------------------------------------------------------------
Vessel description Frequency (Hz) Source level (dB)
----------------------------------------------------------------------------------------------------------------
Outboard drive; 23 ft; 2 engines @ 80 hp...................... 630 156
Twin diesel; 112 ft........................................... 630 159
Small supply ships; 180-279 ft................................ 1,000 125-135 (at 50 m)
Freighter; 443 ft............................................. 41 172
----------------------------------------------------------------------------------------------------------------
Source: Richardson et al., 1995.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, the ambient sound levels at a given
frequency and location can vary by 10-20 dB from day to day (Richardson
et al., 1995).
Very few measurements of ambient sound from Tampa Bay and the
adjoining shelf are available. There are no specific data on ambient
underwater sound levels for the area of the proposed Port and pipeline
route. Shooter et al. (1982) analyzed approximately 12 hours of data
collected in deep (3,280 m) waters in the western GOM and reported
median ambient sound levels of 77-80 dB re: 1 [mu]Pa\2\/Hz. These
levels are likely to be somewhat lower than those occurring in the
vicinity of Tampa Bay, due in large part to the reduced contribution
from surf in deep water.
Known sound levels and frequency ranges associated with
anthropogenic sources similar to those that would be used for this
project are summarized in Table 5. Details of each of the sources are
described in the following text.
[[Page 55654]]
Table 5--Anticipated Source Levels for Construction/Installation and Operations at the Port Dolphin DWP
----------------------------------------------------------------------------------------------------------------
Maximum
broadband
Source Activity Location source level
(re: 1
[micro]Pa)
----------------------------------------------------------------------------------------------------------------
Barge................................. Anchor installation STL buoys (DWP)............ 177 dB
operations.
Tug................................... Anchor installation STL buoys (DWP)............ 205 dB
operations.
Impact hammer \1\..................... Pile driving............... STL buoys (DWP)............ 217 dB
Barge................................. Pipe laying................ Pipeline corridor, DWP to 174 dB
shore.
Tug................................... Transit.................... Offshore/Inshore........... 191 dB
Dredge................................ Dredging................... Likely inshore, offshore if 188 dB
necessary.
HDD................................... Drilling................... Two locations in Tampa Bay. 157 dB
Vibratory driving..................... Sheet pile installation.... Two locations in Tampa Bay. 186 dB
SRV................................... Maneuvering/docking, with DWP........................ 183 dB
thrusters.
SRV................................... Regasification............. DWP........................ 165 dB
----------------------------------------------------------------------------------------------------------------
Source: JASCO, 2008, 2010.
\1\ Source level for impact hammer estimated assuming pulse length of 100 ms.
The sounds produced by these activities fall into one of two sound
types: Pulsed and non-pulsed (defined in next paragraph). The
distinction between these two general sound types is important because
they have differing potential to cause physical effects, particularly
with regard to hearing (e.g., Ward, 1997 in Southall et al., 2007).
Please see Southall et al. (2007) for an in-depth discussion of these
concepts.
Pulsed sounds (e.g., explosions, gunshots, sonic booms, impact pile
driving) are brief, broadband, atonal transients (ANSI, 1986; Harris,
1998) and occur either as isolated events or repeated in some
succession. Pulsed sounds are all characterized by a relatively rapid
rise from ambient pressure to a maximal pressure value followed by a
decay period that may include a period of diminishing, oscillating
maximal and minimal pressures. Pulsed sounds generally have an
increased capacity to induce physical injury as compared with sounds
that lack these features.
Non-pulse (intermittent or continuous) sounds can be tonal,
broadband, or both. Some of these non-pulse sounds can be transient
signals of short duration but without the essential properties of
pulses (e.g., rapid rise time). Examples of non-pulse sounds include
those produced by vessels, aircraft, machinery operations such as
drilling or dredging, vibratory pile driving, and active sonar systems.
The duration of such sounds, as received at a distance, can be greatly
extended in a highly reverberant environment. Many of the sounds
produced by the project would be transient in nature (i.e., the source
moves), such as during vessel docking. Regasification sounds are
continuous (while the SRV is docked) and stationary. The positioning
(maneuvering and docking) of SRVs using thrusters is intermittent
(i.e., every 8 days) and of short duration (i.e., 10 to 30 minutes).
For this project, the only pulsive sounds are associated with pile
driving activities at the offshore Port location (i.e., associated with
anchor installation activities). Impact hammers (proposed for use in
driving buoy anchors) operate by repeatedly dropping a heavy piston
onto a pile to drive the pile into the substrate. Sound generated by
impact hammers is characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers, which would be used to install sheet pile and
possibly pilings for goal posts inshore, install piles by vibrating
them and allowing the weight of the hammer to push them into the
sediment. Vibratory hammers produce significantly less sound than
impact hammers. Peak SPLs may be 180 dB or greater but are generally 10
to 20 dB lower than SPLs generated during impact pile driving of the
same-sized pile (Caltrans, 2009). Rise time is slower, reducing the
probability and severity of injury (USFWS, 2009), and sound energy is
distributed over a greater amount of time (Nedwell and Edwards, 2002;
Carlson et al., 2001).
Sound Attenuation Devices
Sound levels can be greatly reduced during impact pile driving
using sound attenuation devices. There are several types of sound
attenuation devices including bubble curtains, cofferdams, and
isolation casings (also called temporary sound attenuation piles
[TNAP]), and cushion blocks. Port Dolphin considers the installation of
cofferdams to be infeasible for this project. The information available
suggests that bubble curtains, cushion blocks and caps, and TNAP design
offer comparable levels of sound attenuation for pile driving. Port
Dolphin proposes to implement one or more of these techniques during
the pile driving activities needed to install components of the STL
buoys and will make a final decision with regard to the technology to
be used prior to beginning work.
Bubble curtains create a column of air bubbles rising around a pile
from the substrate to the water surface. The air bubbles absorb and
scatter sound waves emanating from the pile, thereby reducing the sound
energy. Bubble curtains may be confined or unconfined. An unconfined
bubble curtain may consist of a ring seated on the substrate and
emitting air bubbles from the bottom. A confined bubble curtain
contains the air bubbles within a flexible or rigid sleeve made from
plastic, cloth, or pipe. Confined bubble curtains generally offer
higher attenuation levels than unconfined curtains because they may
physically block sound waves and they prevent air bubbles from
migrating away from the pile. For this reason, the confined bubble
curtain is commonly used in areas with high current velocity (Caltrans,
2009).
An isolation casing is a hollow pipe that surrounds the pile,
isolating it from the in-water work area. The casing is dewatered
before pile driving. This device provides levels of sound attenuation
similar to that of bubble curtains (Caltrans, 2009). Sound levels can
be reduced by 8 to 14 dB. Cushion blocks consist of materials (e.g.,
wood, nylon) placed atop piles during impact pile driving activities to
reduce source levels. Typically sound reduction can range from 4 to a
maximum of 26 dB.
Both environmental conditions and the characteristics of the sound
attenuation device may influence the
[[Page 55655]]
effectiveness of the device. According to Caltrans (2009):
In general, confined bubble curtains attain better sound
attenuation levels in areas of high current than unconfined bubble
curtains. If an unconfined device is used, high current velocity may
sweep bubbles away from the pile, resulting in reduced levels of sound
attenuation.
Softer substrates may allow for a better seal for the
device, preventing leakage of air bubbles and escape of sound waves.
This increases the effectiveness of the device. Softer substrates also
provide additional attenuation of sound traveling through the
substrate.
Flat bottom topography provides a better seal, enhancing
effectiveness of the sound attenuation device, whereas sloped or
undulating terrain reduces or eliminates its effectiveness.
Air bubbles must be close to the pile; otherwise, sound
may propagate into the water, reducing the effectiveness of the device.
Harder substrates may transmit ground-borne sound and
propagate it into the water column.
The literature presents a wide array of observed attenuation
results for bubble curtains (see, e.g., WSF, 2009; WSDOT, 2008; USFWS,
2009; Caltrans, 2009). The variability in attenuation levels is due to
variation in design, as well as differences in site conditions and
difficulty in properly installing and operating in-water attenuation
devices. As a general rule, reductions of greater than 10 dB cannot be
reliably predicted (Caltrans, 2009).
Sound Thresholds
Since 1997, NMFS has used generic sound exposure thresholds to
determine when an activity in the ocean that produces sound might
result in impacts to a marine mammal such that a take by harassment or
injury might occur (NMFS, 2005b). To date, no studies have been
conducted that examine impacts to marine mammals from which empirical
sound thresholds have been established. Current NMFS practice regarding
exposure of marine mammals to high level sounds is that cetaceans
exposed to impulsive sounds of 180 dB rms or above are considered to
have been taken by Level A (i.e., injurious) harassment. Behavioral
harassment (Level B) is considered to have occurred when marine mammals
are exposed to sounds at or above 160 dB rms for impulse sounds (e.g.,
impact pile driving) and 120 dB rms for continuous sound (e.g., vessel
sound, vibratory pile driving) but below injurious thresholds.
Distance to Sound Thresholds
This section details sound source modeling produced under contract
by the applicant (JASCO, 2008, 2010) and describes the predicted
distances to relevant regulatory sound thresholds for the specified
activities. NMFS has determined that this information represents the
best information available for project sound sources and has used the
information to develop mitigation measures and to estimate potential
incidental take in this document. The modeling scenarios considered all
sound sources associated with the project and were developed to
thoroughly characterize the various construction/installation and
operation activities expected. The relevant information is summarized
in Table 6. The equipment list associated with each activity is based
on current construction plans for the Port (Ocean Specialists, 2007).
For each piece of equipment specified, proxy vessels were selected from
JASCO Research's database of underwater sound measurements. The sound
propagation model used several parameters, including expected water
column sound speeds, bathymetry (water depth and shape of the ocean
bottom), and bottom geoacoustic properties (which indicate how much
sound is reflected off of the ocean bottom), to estimate the radii of
sound impacts (JASCO, 2008). Modeling scenario locations are depicted
in Figure 1-4 of Port Dolphin's application. Please see Appendices C
and D in Port Dolphin's application for a detailed description of this
sound source modeling.
Table 6--Representative Scenarios Modeled During the Port Dolphin Sound Source Analysis and Radial Distance to
Thresholds
----------------------------------------------------------------------------------------------------------------
Approximate area
Activity Source Modeled location Distance to encompassed by
threshold 1,2 threshold \2\
----------------------------------------------------------------------------------------------------------------
Buoy installation............. Crane vessel, cargo North STL buoy; 180 dB: <0.2 km. 180 dB: <0.13 km
barge, support offshore DWP site. 120 dB: 3.9 km.. \2\
vessel. 120 dB: 48 km
\2\
Impact hammering.............. Impact hammer........ Y-connector; offshore 180 dB: 0.18 km. 180 dB: 0.10 km
DWP site. 160 dB: 4.5 km.. \2\
160 dB: 64 km
\2\
Pipelaying, offshore.......... Barge, two anchor 15-m isobath......... 180 dB: <0.2 km. 180 dB: <0.13 km
handling tugs, 120 dB: 7.5 km.. \2\
support tug. 120 dB: 177 km
\2\
Pipelaying, inshore........... Barge, two anchor Tampa Bay............ 180 dB: <0.2 km. 180 dB: <0.13 km
handling tugs, 120 dB: 6.0 km.. \2\
support tug. 120 dB: 113 km
\2\
Pipeline burial, offshore..... Plow system, two 15-m isobath......... 180 dB: <0.2 km. 180 dB: <0.13 km
anchor handling tugs. 120 dB: 8.4 km.. \2\
120 dB: 222 km
\2\
Pipeline burial, inshore...... Plow system, two Tampa Bay............ 180 dB: <0.2 km. 180 dB: <0.13 km
anchor handling tugs. 120 dB: 6.7 km.. \2\
120 dB: 141 km
\2\
HDD........................... Floating spud barge, Tampa Bay............ 180 dB: <0.01 km 180 dB: <0.00 km
crane mounted drill, 120 dB: 0.24 km. \2\
welding equipment, 120 dB: 0.2 km
air compressor, \2\
generator.
HDD vibratory driving......... Floating spud barge, Tampa Bay............ 180 dB: <0.01 km 180 dB: <0.00 km
vibrator, welding 120 dB: 12.6 km. \2\
equipment, air 120 dB: 499 km
compressor, \2\
generator.
Docking at buoy, dead slow, SRV.................. STL buoy; offshore 180 dB: <0.01 km 180 dB: <0.00 km
two bow thrusters and one DWP site. 120 dB: 3.6 km.. \2\
stern thruster. 120 dB: 41 km
\2\
Regasification................ SRV.................. STL buoy; offshore 180 dB: 0.00 km. 180 dB: <0.00 km
DWP site. 120 dB: 0.17 km. \2\
120 dB: 0.09 km
\2\
----------------------------------------------------------------------------------------------------------------
Source: JASCO, 2008, 2010.
\1\ All distances are unweighted, 95th percentile radial distances.
\2\ For distances not given precisely (e.g., <0.2 km) area of ensonification was modeled using a radial distance
of 200 m. Although the distance to threshold would be less than 200 m, it is not possible to specifically
calculate the distance because the scenarios involve multiple vessel components.
[[Page 55656]]
Note that in many cases the scenarios involve multiple pieces of
equipment. Although equipment spacing would vary during the course of
operations, a single layout must be assumed for modeling purposes. As
such, where multiple vessels were involved in the scenarios listed in
Table 6 the following layout was assumed:
The barge used for the main operation in each scenario
(e.g., crane vessel, pipe laying barge, pipe burial barge) was set in
the middle of the group of vessels.
For four or fewer tugs (anchor handling and/or support),
tugs were spaced at a range of 100 m (328 ft) from the center of the
barge. Note that the pipe laying/burial barge itself is 122 m long x 30
m wide (400 x 100 ft).
The radii to sound thresholds vary for the same activity depending
on water depth, because the transmission of lower-frequency sound waves
can be significantly reduced in shallower water. As a result, the radii
to the Level A and Level B harassment isopleths in Tampa Bay (i.e.,
shallower water) are shorter than those that would occur offshore. In
addition, much of the energy from the vessels associated with
pipelaying occurs at low frequencies and would propagate poorly in
shallower water.
Although sounds created by construction equipment and vessels would
be continuous during pipeline installation, activities would progress
slowly along the pipeline route as the pipeline is laid and buried and
the trench backfilled. Any one area would be subject to the maximum
sound levels for only 1 to 2 days at a time as the construction
activities pass that area. Sound modeling indicates that, overall,
operational sound associated with the proposed project is consistent
with other man-made underwater sound sources in the area (e.g.,
commercial shipping and dredging). Appendix E of Port Dolphin's
application presents Level B harassment sound field graphics for
construction activities.
Specific Activity Descriptions--As described previously, the
applicant provided detailed sound source modeling for all sound-
producing activities associated with the project. In the following
sections, each specific type of activity is described in terms of the
modeling scenario; the type, duration, and timing of sound produced by
the activity; and the radial distances to relevant sound thresholds.
All radial distances to thresholds presented in the following sections
are modeled, and may be different from the actual distances as
determined through site-specific acoustic monitoring conducted during
the specified activities.
Buoy Installation--Proxies were selected for the crane and support
vessels based on vessel specifications. While a cargo barge may be
present on-site for a portion of the operations, Port Dolphin assumed
that this barge would typically not be under power. Installation of the
buoys at the Port would produce continuous sound for a relatively short
period of time during summer, with the 120-dB isopleth located 3.9 km
(2.4 mi) from each STL buoy location.
Impact Pile Driving--During the construction period, impact
hammering would produce the loudest sound levels but would likely occur
only for short periods of time. The source depth for pile driving was
set to approximately half the local water depth. In actuality, sound
would radiate from all portions of the pilings; this midwater column
value is a precautionary estimate of the depth for an equivalent point
source, as losses due to bottom and surface interactions would be less
for a source at mid-depth than for one near the sea floor or surface.
Impact hammering operations would involve a pipe lay barge and tugs,
similar to pipe laying operations. However, because the potential
impact to marine mammals is different for impulsive and continuous
sources, impact hammering sound (an impulsive source) is considered
separately from vessel sound (non-pulsed sources). Note that the source
levels from impact hammering are much higher than those from the
vessels that are likely to be on-site. Impact hammering offshore would
encompass an area with a radius of approximately 180 m (591 ft) to the
Level A threshold; radii to the 160-dB isopleths for this impulsive
source would be at 4.5 km (2.8 mi).
Pipe Laying--Pipe laying activities would generate continuous,
transient, and variable sound levels during construction predominantly
during fall, with some activity during late summer and early winter.
Two sites were selected for pipe laying: one approximately midway along
the offshore portion of the pipeline and another along the inshore
portion. Equipment lists for the offshore and inshore sites are
identical: a pipe laying barge, two tugs involved in re-setting of
anchors, and a third tug in transit. Sound impacts from pipelaying
would produce a 6.0 or 7.5 km (3.7-4.7 mi) radius to the 120-dB
isopleth inshore and offshore, respectively.
Pipe Burial--Pipeline burial using the plow system would generate
continuous, transient, and variable sound levels during construction,
primarily during fall and winter. Pipeline burial would be used
infrequently during the construction period. Similarly to pipe laying,
pipe burial using a trenching plow system would consist of an anchored
barge accompanied by two anchor handling tugs. In addition, sound would
be generated by the plow used to bury the pipeline. Detailed source
level data were not available for plow operations. However, Aspen
Environmental Group (2005) reported a broadband source level of 185 dB.
Based on this information, similar source levels from dredge operations
(Greene, 1987) were used for the applicant's modeling purposes. Note
that the dredge source levels include the sound from the barge upon
which the dredge is operated; consequently, a separate barge is not
specified for plowing operations in Table 6. The modeling scenario used
the depth of the barge hull under the water as the sound source depth,
rather than the depth of the actual dredge work. This is because
observations from clamshell dredging show that the highest levels of
underwater sound are emitted from equipment on the barge (propagating
through the hull) rather than from the scraping sounds of the dredge
itself (Richardson et al., 1995). Pipeline burial using the plow system
produces sound attenuating to the 120-dB isopleth at 6.7 km (4.2 mi)
inshore and 8.4 km (5.2 mi) offshore.
HDD--HDD within Tampa Bay would produce continuous sound levels and
is expected to occur during summer. Installation of the goal posts
(described previously under ``Pipeline Installation'') at each HDD
location would produce a continuous sound for a relatively short period
of time and would only occur during summer. HDD would be employed for
installation of the pipeline at a number of locations along the inshore
portion of the route, including the Port Manatee shore approach and two
crossings of the existing Gulfstream pipeline. Drilling and vibratory
driving (for goal posts/sheet pile) would be conducted from a floating
spud barge approximately 41 m in length. Drilling would involve a
crane-mounted drill, suspended from a crawler crane on the barge. The
barge would also be equipped with welding equipment, an air compressor,
and a generator.
Source levels for drilling of the pilot holes are based on
measurements made by Greene (1987) during drilling operations in the
Beaufort Sea. As with drilling from a barge, these measurements include
contributions from both the drill assembly itself and from equipment on
the drill platform
[[Page 55657]]
(e.g., generators). Because the dominant sound source is equipment
located on the drilling vessel (Richardson et al., 1995) rather than
the drilling or scraping itself, a source level height of 2.2 m was
used, as it was for other barge-mounted activities modeled by JASCO.
Source levels for the vibratory driver were derived from
measurements made by JASCO. The vibratory driver was mounted on a
moored barge during the measurements, and so sound contributions from
equipment on the barge are included in the source level estimates. The
measured driver is larger than the vibratory driver planned for use at
Port Dolphin. However, very few measurements of underwater sound exist
for pile drivers of this size, and in most cases the available reports
do not describe the vibratory driver used. Additionally, scaling by
vibratory driver specifications (e.g., the eccentric moment) is made
difficult by the fact that pile driving source levels depend not only
on the equipment but also on the piling, substrate and environment. As
such, JASCO's un-scaled measurements of underwater sound are used here
as a conservative estimate of the sound likely to be generated during
installation of the goal posts/sheet pile. As for the impact pile
driving described previously, the source depth for pile driving was
conservatively set to half the local water depth, i.e., 3.5 m.
Modeling results (JASCO, 2010) indicate that the 120-dB isopleth
would extend 240 m (787 ft) from the drilling operation, while the 120-
dB isopleth for HDD vibratory driving would extend 12.6 km (7.8 mi)
from the source.
SRV Docking--Once the SRV completes its approach to Port Dolphin
and is within approximately 5.6 km (3.5 mi) of the Port, bow and stern
thrusters would be utilized. Thruster use would vary, operating for 10
to 30 minutes to allow for the proper positioning of the vessel and for
connection to the STL buoy. Docking or berthing would occur at
alternate STL buoys approximately every 8 days. Sound modeling,
assessing the periodic use of the thrusters (i.e., every 8 days)
producing an intermittent and moving sound, indicated that the 120-dB
isopleth would occur at 3.6 km (2.2 mi) from the SRV.
Operational procedures for the SRVs specify probable use of
thrusters during approach and docking. Speed is gradually reduced as
the SRV approaches the unloading buoys, until main propulsion is at
dead slow. Bow and stern thrusters are used during docking. Once
moored, ship's propulsion is not required for positioning. Based on
these operational procedures, the sample situation described in Table 6
was selected for modeling; i.e., docking at the northern buoy, using
both bow thrusters and one stern thruster.
Very little information is available on the underwater sound levels
produced by LNG carriers. However, some data and empirical formulas
have been developed for large tankers in general. At typical cruising
speeds, source levels from such vessels are dominated by propeller
cavitation (Sponagle, 1988; Seol et al., 2002). As described by LGL and
JASCO (2005), an empirical expression for the source spectrum level (1
Hz bandwidth) in the frequency range between 100 Hz and 10 kHz is
SL = 163 + 10 log BD\4\N\3\ f-2
where B is the number of blades, D is the propeller diameter in meters,
N is the number of propeller revolutions per second, and f is the
frequency in Hz. For frequencies less than 100 Hz, the source level is
assumed to be constant at the 100 Hz level. In the case of ducted
propellers (e.g., bow and stern thrusters), the constant is
approximately 7 dB larger. Specifications for the main propulsion
system are based on a typical carrier, and are similar to those
described by LGL and JASCO (2005). Bow and stern thrusters are expected
to be single-speed, controllable-pitch devices, with power ratings of
2,000 kW each for the bow thrusters and 1,200 kW each for the stern
thrusters. Based on these values, diameters and rates of revolution for
the thrusters were based on specifications for the most common models
currently available. The above model is not able to take into account
the reduction in source levels that would result from a change in pitch
at lower power outputs; hence, the modeled source levels are
conservative (i.e., represent maximum expected levels of underwater
sound).
Regasification--The SRV would regasify its LNG cargo while moored
at the STL buoy. Sound levels for regasification are low, and the
modeling predicts that the 120-dB isopleths would be only 170 m (558
ft) from the source.
The following additional sources of underwater sound are expected
to be present during construction of the DWP, but were not modeled:
Dredging: Dredging would be involved in a few stages of
construction, including HDD (discussed later) and pipelaying at the
Sunshine Bridge crossing (Ocean Specialists, 2007). This would involve
a clamshell or bucket-style dredge, operated from a barge while one or
more additional barges carry out other tasks nearby. Measurements taken
by JASCO during operation of a clamshell dredge indicated source levels
of approximately 150-155 dB, i.e., roughly 20 dB lower than the source
levels associated with the barge used during pipe laying operations. As
such, dredging may be considered an insignificant source of sound
compared with operation of the barges that would also be present.
Transponders: Once the port is operational, an additional
source of underwater sound in the vicinity of the unloading buoys would
be the acoustic transponders installed on the buoys. Information was
not available on the specific transponders intended for use at the DWP;
however, specifications from commercially available buoy positioning
transponders indicate operating frequencies of a few tens of kHz, and
source levels of approximately 190 dB. Given this estimated broadband
source level, we may estimate ranges to various threshold values
assuming simple spherical spreading, i.e., RL = SL -
20log10(r). Solving for r shows that received levels would
drop to 180 dB at a range of approximately 3 m, and to 160 dB at a
range of approximately 32 m; further, this sound source would be highly
intermittent, as the transponders would only transmit, briefly, when
interrogated by the SRV-based command unit. As such, only marine
mammals passing very near the unloading buoys during the brief period
of transmittance would potentially be affected, and effects from these
sources may be considered discountable.
Comments and Responses
On March 1, 2011, NMFS published a notice of receipt of an
application for a Letter of Authorization (LOA) in the Federal Register
(76 FR 11205) and requested comments and information from the public
for 30 days. NMFS did not receive any substantive comments. Description
of Marine Mammals in the Area of the Specified Activity
Twenty-nine marine mammals (28 cetaceans and the Florida manatee
[Trichechus manatus]) have documented occurrences in the GOM (Wursig et
al., 2000). The manatee is under the jurisdiction of the U.S. Fish and
Wildlife Service, and will not be discussed further in this document.
Of the cetaceans, seven are mysticetes (baleen whales) and 21 are
odontocetes (toothed whales, including dolphins). Table 7 contains a
summary of relevant information for each of these 28 species.
[[Page 55658]]
Table 7--Marine Mammals in the Gulf of Mexico
----------------------------------------------------------------------------------------------------------------
Typical habitat
Species Status \a\ Occurrence \b\ -----------------------------------------------
Coastal Shelf Slope/Deep
----------------------------------------------------------------------------------------------------------------
Order Cetacea
----------------------------------------------------------------------------------------------------------------
Suborder Mysticeti
----------------------------------------------------------------------------------------------------------------
Family Balaenidae:
North Atlantic right whale E 1 .............. X X
(Eubalaena glacialis)......
Family Balaenopteridae.
Blue whale (Balaenoptera E 1 .............. X X
musculus)..................
Bryde's whale (Balaenoptera .............. 3 .............. X X
edeni).....................
Fin whale (Balaenoptera E 2 .............. X X
physalus)..................
Humpback whale (Megaptera E 2 .............. X X
novaeangliae)..............
Minke whale (Balaenoptera .............. 2 .............. X X
acutorostrata).................
Sei whale (Balaenoptera E 2 .............. X X
borealis)......................
----------------------------------------------------------------------------------------------------------------
Suborder Odontoceti
----------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Dwarf sperm whale (Kogia .............. 3 .............. X X
sima)......................
Pygmy sperm whale (Kogia .............. 3 .............. X X
breviceps).................
Sperm whale (Physeter E 4 .............. X X
macrocephalus).............
----------------------------------------------------------------------------------------------------------------
Family Ziphiidae:
Blainville's beaked whale .............. 2 \c\ .............. X X
(Mesoplodon densirostris)..
Cuvier's beaked whale .............. 2 \c\ .............. X X
(Ziphius cavirostris)......
Gervais' beaked whale .............. 3 \c\ .............. X X
(Mesoplodon europaeus).....
Sowerby's beaked whale .............. 1 \c\ .............. X X
(Mesoplodon bidens)........
Family Delphinidae:
Atlantic spotted dolphin .............. 4 X X X
(Stenella frontalis).......
Bottlenose dolphin (Tursiops .............. 4 X X X
truncatus).................
Clymene dolphin (Stenella .............. 4 .............. X X
clymene)...................
False killer whale .............. 3 .............. X X
(Pseudorca crassidens).....
Fraser's dolphin .............. 4 .............. X X
(Lagenodelphis hosei)......
Killer whale (Orcinus orca). .............. 3 .............. .............. X
Melon-headed whale .............. 4 .............. .............. X
(Peponocephala electra)....
Pantropical spotted dolphin .............. 4 .............. X X
(Stenella attenuata).......
Pygmy killer whale (Feresa .............. 3 .............. X X
attenuata).................
Short-finned pilot whale .............. 4 .............. X X
(Globicephala
macrorhynchus).............
Risso's dolphin (Grampus .............. 4 .............. X X
griseus)...................
Rough-toothed dolphin (Steno .............. 4 .............. X X
bredanensis)...............
Spinner dolphin (Stenella .............. 4 .............. X X
longirostris)..............
Striped dolphin (Stenella .............. 4 .............. X X
coeruleoalba)..............
----------------------------------------------------------------------------------------------------------------
Source: W[uuml]rsig et al., 2000
\a\ Status: E = Listed as endangered under the Endangered Species Act.
\b\ Occurrence: 1 = extralimital; 2 = rare; 3 = uncommon; 4 = common.
\c\ Beaked whales in the GOM may be somewhat more common than survey data indicate, as beaked whales are
difficult to sight and identify to species. Most surveys have been conducted in sea states that are not
optimal for sighting beaked whales.
Of these 28 cetacean species, based on available survey data, only
the bottlenose dolphin and Atlantic spotted dolphin are likely to occur
regularly in the vicinity of the project area (i.e., coastal and shelf
waters of the eastern GOM) (Fulling et al., 2003). Because a small
portion of the sound produced by the activity is predicted to extend
into the mid-shelf depth stratum, three other species of cetacean--
pygmy and dwarf sperm whales and the rough-toothed dolphin--could be
affected. Other species of dolphins and an occasional whale are
sometimes observed in nearshore GOM waters and might infrequently
strand, but these are not considered normal occurrences for those
deepwater species that occur more regularly in waters around and
seaward of the continental shelf break (Mullin and Fulling, 2003a;
Mullin et al., 2004). As a result, the potential effects of the
specified activity are analyzed only for these five species. As the
species to be most affected by the specified activity, bottlenose and
spotted dolphin occurrences relative to the project area are discussed
in more detail in the following paragraphs.
The cetacean fauna of the northern and eastern GOM continental
shelf, including the project area, typically consists of the bottlenose
dolphin and the Atlantic spotted dolphin (Davis and Fargion, 1996;
Jefferson and Schiro, 1997; Davis et al., 1998; Davis et al., 2000;
W[uuml]rsig et al., 2000). At the shelf edge and within the deeper
waters of the continental slope, the cetacean community typically
includes nineteen species, including the Bryde's whale, sperm whale,
pygmy and dwarf sperm whales, three species of beaked whales, and
twelve species of oceanic dolphins. Oceanographic and bathymetric
features (e.g., eddies, water temperature, salinity) are important
factors in determining the distribution of marine mammals, in large
part because the presence of prey is frequently influenced by such
features (Katona and Whitehead, 1988; Biggs et al., 2000; Wormuth et
al., 2000; Davis et al., 2002). The presence of specific hydrographic
and/or bathymetric features and discontinuities (e.g., abrupt
[[Page 55659]]
temperature differentials, current edges, upwelling areas, sea mounts,
banks, shoals, the continental shelf edge) may also affect marine
mammal distribution (USDON, 2003).
The following discussions of the population status of GOM marine
mammals use categories adapted from W[uuml]rsig et al. (2000):
Common: A species that is abundant and widespread
throughout the region in which it occurs;
Uncommon: A species that does not occur in large numbers
and may or may not be widely distributed throughout the region in which
it occurs;
Rare: A species present in such small numbers throughout
the region that it is seldom seen; and
Extralimital: A species known on the basis of few records
that are probably the result of unusual movements of few individuals
into the region.
Data historically acquired during aerial and shipboard surveys
conducted within the eastern GOM were analyzed by marine mammal
researchers and summarized in USDON (2003). To increase the utility of
the species sightings data, marine mammal occurrence and distribution
data were partitioned into both seasonal and water depth categories.
This partitioning is supported by distribution patterns (e.g.,
sightings over the continental shelf, sightings beyond the continental
shelf) observed during large[hyphen]scale surveys (e.g., Cetacean and
Turtle Assessment Program [CETAP] surveys; CETAP, 1982; Hain et al.,
1985; Winn et al., 1987). Seasonal categories included in USDON (2003)
and employed in this analysis were:
Winter: December 21 through March 20;
Spring: March 21 through June 20;
Summer: June 21 through September 20; and
Fall: September 21 through December 20.
Water depth categories, or depth strata, included in USDON (2003)
and employed in this analysis were as follows:
Nearshore: 0 to 120 ft (0 to 36.6 m);
Mid[hyphen]shelf: 120 to 300 ft (36.6 to 91.4 m);
Shelf[hyphen]edge: 300 to 6,600 ft (91.4 to 2,000 m); and
Slope: > 6,600 ft (> 2,000 m).
The U.S. Department of the Navy (USDON, 2003) reviewed available
marine mammal survey data for the eastern GOM and summarized species
presence and distribution on a seasonal basis. Relevant findings
pertinent to marine mammals include the following:
Spring is the season with the highest number of cetacean
occurrence records, although high numbers of cetacean occurrence
records were also noted for summer;
Fall and winter are the two seasons with the lowest number
of occurrence records and total number of cetaceans;
Higher numbers in spring and summer are possibly due to
the higher survey effort usually expended during those months (when
sighting conditions are optimal); and
There are fewer sighting records in fall than in the other
seasons, likely attributable to suboptimal survey conditions (i.e.,
reduction in sightability).
Mysticetes
The Bryde's whale is the most frequently sighted mysticete in the
Gulf, though considered uncommon. Strandings and sightings data suggest
that this species may be present throughout the year, generally in the
northeastern Gulf near the 100-m (328-ft) isobath between the
Mississippi River delta and southern Florida (Davis et al., 2000;
W[uuml]rsig et al., 2000). The remaining six mysticete whales (blue,
fin, humpback, minke, sei, and North Atlantic right whales) are
considered rare or extralimital in the GOM (Jefferson, 1996; Jefferson
and Schiro, 1997). Mysticete whales, including the Bryde's whale, could
occur within the project area although such occurrence would be
extremely unlikely.
Odontocetes
Bottlenose dolphins and spotted dolphins are known to occur
regularly in the project area and are the species to be most affected
by the project. In addition, there is some possibility that pygmy and
dwarf sperm whales and rough-toothed dolphins could occur in deeper
waters ensonified by some offshore project activities. Most of the
odontocetes known to occur within the Gulf (Table 7) are considered
common. Exceptions include the beaked whales, with most being rare or
extralimital, and the dwarf and pygmy sperm whales, which are
considered uncommon. The frequency of occurrence of beaked whales and
dwarf and pygmy sperm whales are most likely underestimated because
these cryptic species are submerged much of the time and avoid aircraft
and ships (W[uuml]rsig et al., 1998). Consequently, these species may
be somewhat more common than is indicated by survey data but are still
likely to be relatively uncommon. The sperm whale is considered common
in the Gulf (Jefferson, 1996; Jefferson and Schiro, 1997; Davis et al.,
2000; Waring et al., 2006). Sightings data suggest a Gulf[hyphen]wide
distribution on the continental slope. Congregations of sperm whales
are common along the continental shelf edge in the vicinity of the
Mississippi River delta in water depths of 500 to 2,000 m (1,640-6,562
ft). As a result of these consistent sightings, it is believed that
there is a resident population of sperm whales in the Gulf consisting
of adult females, calves, and immature individuals (Brandon and
Fargion, 1993; Mullin et al., 1994; Sparks et al., 1993; Jefferson and
Schiro, 1997). Though most odontocetes (including delphinids) are
considered common in the GOM, they prefer waters of the continental
shelf edge (approximately 200 m [656 ft]) or deeper waters of the
continental slope. Therefore, it is unlikely that these species would
occur within the project area (i.e., Tampa Bay and nearshore waters).
Due to the rarity of the majority of odontocete species, as well as the
mysticetes discussed previously, in the proposed project area and the
remote chance they would be affected by Port Dolphin's proposed port
operations, these species are not considered further in this analysis.
The most commonly sighted cetaceans on the GOM continental shelf
(in terms of numbers of individual sightings) during systematic surveys
conducted in the mid to late 1990s (i.e., GulfCet II) were bottlenose
dolphins and Atlantic spotted dolphins. Brief discussions of these
commonly sighted marine mammal species are provided in the following
subsections.
Bottlenose dolphins--The bottlenose dolphin is a common inhabitant
of both the continental shelf and slope in the GOM, generally in waters
less than 20 m (66 ft) (Griffin and Griffin, 2003). The species is also
distributed throughout the bays, sounds, and estuaries of the GOM
(Mullin et al., 1990). Bottlenose dolphins are opportunistic feeders,
taking a wide variety of fish, cephalopods, and shrimp (Wells and
Scott, 1999) and using a wide variety of feeding strategies (Shane,
1990). In the GOM, bottlenose dolphins often feed in association with
shrimp trawlers (Fertl and Leatherwood, 1997). In addition to the use
of active echolocation to find food, bottlenose dolphins likely detect
and orient to fish prey by listening for the sounds prey produce--so-
called `passive listening' (Barros and Myrberg, 1987; Gannon et al.,
2005). Nearshore bottlenose dolphins prey predominately on coastal fish
and cephalopods, while offshore individuals prey on pelagic cephalopods
and a large variety of epi- and mesopelagic fish species (Van Waerebeek
et al., 1990; Mead and Potter, 1995).
[[Page 55660]]
NMFS recognizes several stocks of bottlenose dolphins in the GOM,
including a northern oceanic stock; a continental shelf and slope
stock; western, northern, and eastern coastal stocks; and a group of 32
bay, sound, and estuarine stocks (Blaylock et al., 1995; Waring et al.,
2006). Bottlenose dolphins likely occur within both offshore and
nearshore waters of the project area. Bottlenose dolphins present in
the project area would likely be represented by individuals from the
eastern coastal stock and the relevant bay, sound, and estuarine
stocks.
Bottlenose dolphins along the U.S. coastline are believed to be
organized into local populations, or stocks, each occupying a small
region of coast with some migration to and from inshore and offshore
waters (Schmidly, 1981). The seaward boundary for coastal stocks, the
20-m (66-ft) isobath, generally corresponds to survey strata (Scott,
1990; Blaylock and Hoggard, 1994; Fulling et al., 2003) and represents
a management boundary rather than an ecological boundary. Both
``coastal/nearshore'' and ``offshore'' ecotypes of bottlenose dolphins
(Hersh and Duffield, 1990) occur in the GOM (LeDuc and Curry, 1998),
and both could potentially occur in coastal waters. The best abundance
estimate available for the northern GOM eastern coastal stock of
bottlenose dolphins is 7,702, with a minimum population estimate of
6,551. The status of the eastern coastal stock relative to optimum
sustainable population (OSP) level is not known and population trends
cannot be determined due to insufficient data. The eastern coastal
stock is not considered a strategic stock under the MMPA because the
stock's average annual human-related mortality and serious injury does
not exceed potential biological removal (PBR) (Waring et al., 2010).
Bottlenose dolphins are distributed throughout the bays, sounds and
estuaries of the GOM (Mullin, 1988). The identification of
biologically-meaningful ``stocks'' of bottlenose dolphins in these
waters is complicated by the high degree of behavioral variability
exhibited by this species (Shane et al., 1986; Wells and Scott, 1999;
Wells, 2003), and by the lack of requisite information for much of the
region. However, distinct stocks are provisionally identified in each
of 32 areas of contiguous, enclosed or semi-enclosed bodies of water
adjacent to the northern GOM. Bay, sound, and estuarine dolphins found
in the project area would likely be from Tampa Bay or Sarasota Bay.
These ``communities'' include resident dolphins that regularly
share large portions of their ranges, exhibit similar distinct genetic
profiles, and interact with each other to a much greater extent than
with dolphins in adjacent waters. While these communities do not
constitute closed demographic populations, the geographic nature of
these areas and long-term, multi-generational stability of residency
patterns suggest that they may exist as discrete, functioning units of
their ecosystems. Members of these stocks emphasize use of the bay,
sound, or estuary waters, with limited movements through passes to the
GOM (Shane, 1977, 1990; Gruber, 1981; Irvine et al., 1981; Maze and
W[uuml]rsig, 1999; Lynn and W[uuml]rsig, 2002; Fazioli et al., 2006).
These habitat use patterns are reflected in the ecology of the dolphins
in some areas; for example, residents of Sarasota Bay, Florida, lack
squid in their diet, unlike non-resident dolphins found stranded on
nearby Gulf beaches (Barros and Wells, 1998).
Genetic exchange occurs between resident communities; hence the
application of the demographically and behaviorally-based term
``community'' rather than ``population'' (Wells, 1986a; Sellas et al.,
2005). A variety of potential exchange mechanisms occur in the Gulf.
Small numbers of inshore dolphins traveling between regions have been
reported, with patterns ranging from traveling through adjacent
communities (Wells, 1986b; Wells et al., 1996a,b) to movements over
distances of several hundred kilometers in Texas waters (Gruber, 1981;
Lynn and W[uuml]rsig, 2002). In many areas, year-round residents co-
occur with non-resident dolphins, providing potential opportunities for
genetic exchange. Non-residents exhibit a variety of patterns, ranging
from apparent nomadism recorded as transience to apparent seasonal or
non-seasonal migrations. Passes, especially the mouths of the larger
estuaries, serve as mixing areas. For example, several communities mix
at the mouth of Tampa Bay (Wells, 1986a). Seasonal movements of
dolphins into and out of some of the bays, sounds and estuaries provide
additional opportunities for genetic exchange with residents, and
complicate the identification of stocks in coastal and inshore waters.
In larger bay systems (e.g., Tampa Bay), seasonal changes in
abundance suggest possible migrations, and fall/winter increases in
abundance have been noted for Tampa Bay (Scott et al., 1989). A number
of geographically and socially distinct subgroupings of dolphins in
some regions, including Tampa Bay, have been identified, but the
importance of these distinctions to stock designations remains
undetermined. For Tampa Bay, Urian et al. (2009) recently described
fine-scale population structuring into five discrete communities
(including the adjacent Sarasota Bay community) that differed in their
social interactions and ranging patterns. Structure was found despite a
lack of physiographic barriers to movement within this large, open
embayment.
In the vicinity of the action area, there are distinct geographic
subdivisions with year-round resident animals from Tampa Bay, Sarasota
Bay, and Charlotte Harbor as well as a seasonal coastal stock
(discussed previously; 1 to 12 km [0.6-7.5 mi] offshore) with mixing on
a limited basis (Wells et al., 1996; Wells and Scott, 2002; Sellas et
al., 2005). The Sarasota community's range extends from southern Tampa
Bay southward through Sarasota Bay, and into the GOM about 1 km
offshore. Waring et al. (2010) identified the animals in Tampa Bay as
having a best estimate of abundance of 559 individuals (based on 1994
data) and those in Sarasota Bay as having a best abundance estimate of
160 individuals (based on 2007 data). The status of the stock relative
to OSP is unknown. Because most of the stock sizes are currently
unknown, but likely small, and relatively few mortalities or serious
injuries would exceed PBR, NMFS considers that each of these stocks is
a strategic stock under the MMPA (Waring et al., 2010).
Atlantic spotted dolphins--Atlantic spotted dolphins are widely
distributed in warm temperate and tropical waters of the Atlantic
Ocean, including the GOM (Waring et al., 2006). In the northern Gulf,
these animals occur mainly on the continental shelf (Jefferson and
Schiro, 1997). During GulfCet II aerial and shipboard surveys in the
northern GOM, Atlantic spotted dolphins were seen at water depths
ranging from 22 to 222 m (72-728 ft) (Mullin and Hoggard, 2000). On the
shelf, they were second in abundance to bottlenose dolphins. Atlantic
spotted dolphins can be expected to occur on the continental shelf
during all seasons. However, they may be more common during spring
(Jefferson and Schiro, 1997; Mullin and Hoggard, 2000). It is expected
that Atlantic spotted dolphins could occur within offshore waters of
the project area.
Atlantic spotted dolphins in the northern GOM are abundant in
continental shelf waters from between 10 and 200 m (33 to 656 ft) to
slope waters < 500 m (1,640 ft) (Fulling et al. 2003; Mullin and
Fulling, 2003a). Griffin and Griffin (2003) reported that
[[Page 55661]]
on the west Florida Shelf they are more common in waters from 20 to 180
m (66 to 591 ft), while Mullin et al. (2004) found that Atlantic
spotted dolphins were sighted in waters with a bottom depth typically <
300 m (984 ft). Griffin and Griffin (2004) reported higher abundances
of spotted dolphins on the west Florida Shelf between the months of
November and May than during the rest of the year.
Atlantic spotted dolphins in the GOM have been seen feeding
cooperatively on clupeid fishes (e.g., herring, sardine) and are known
to feed in association with shrimp trawlers (Fertl and W[uuml]rsig,
1995; Fertl and Leatherwood, 1997, respectively). In the Bahamas, this
species has been observed to chase and catch flying fish (MacLeod et
al., 2004). The only information on dive depth for this species is
based on a satellite-tagged individual from the GOM (Davis et al.,
1996). This individual made short, shallow dives (more than 76 percent
of the time to depths < 10 m) over the continental shelf, although some
dives were as deep as 40 to 60 m (Davis et al., 1996).
The GOM population is considered a separate stock for management
purposes. The most recent abundance estimate for Atlantic spotted
dolphin in the GOM, based on pooled survey data from 2000 and 2001, was
37,611 (Waring et al., 2009). These animals were found entirely in OCS
waters; the abundance estimate for oceanic waters, from surveys
conducted in 2003-04, was zero. There is insufficient information for
this stock to determine PBR or its status relative to OSP. Despite an
undetermined PBR and unknown population size, the GOM stock is not
considered a strategic stock under the MMPA because previous estimates
of population size have been large compared to the number of cases of
documented human-related mortality and serious injury.
In addition to bottlenose and spotted dolphins, three other species
that frequent the mid-shelf stratum could be exposed to sound from
certain project activities and the potential for incidental harassment
of these species has been evaluated (see ESTIMATED INCIDENTAL
HARASSMENT). Dwarf and pygmy sperm whales and rough-toothed dolphins
may be expected to occur in the mid-shelf stratum on a seasonal basis.
The area of actual construction and operations for Port Dolphin is
entirely contained within the nearshore depth stratum (0 to 37 m; depth
strata were listed earlier). Maximum depth at the DWP is approximately
31 m, while the pipeline route transits increasingly shallower waters
until entering Tampa Bay and subsequently making landfall. However,
while the actual construction activities will be entirely contained
within the nearshore stratum, the sound field produced by certain
construction activity, and thus the area of effect, extends into the
mid-shelf depth stratum (37 to 91 m). Most sound would be contained
within the nearshore stratum. The one exception is for the offshore
pipelaying activity, which would occur only from late summer 2013
through early winter 2013-14. The Level B sound field for this activity
would be 99.9 percent contained within the nearshore stratum, with 0.1
percent potentially entering the mid-shelf stratum.
Background on Marine Mammal Hearing
Different kinds of marine life are sensitive to different
frequencies of sound. Based on available behavioral data, audiograms
derived using auditory evoked potential techniques, anatomical
modeling, and other data, Southall et al. (2007) designated functional
hearing groups for marine mammals and estimated the lower and upper
frequencies of functional hearing of the groups. The functional groups
and the associated frequencies are indicated below (though animals are
less sensitive to sounds at the outer edge of their functional range
and most sensitive to sounds of frequencies within a smaller range
somewhere in the middle of their functional hearing range):
Low-frequency cetaceans (mysticetes): Functional hearing
is estimated to occur between approximately 7 Hz and 22 kHz;
Mid-frequency cetaceans (dolphins, larger toothed whales,
beaked and bottlenose whales): Functional hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (true porpoises, river dolphins,
Kogia sp.): Functional hearing is estimated to occur between
approximately 200 Hz and 180 kHz; and
Pinnipeds in water: Functional hearing is estimated to
occur between approximately 75 Hz and 75 kHz, with the greatest
sensitivity between approximately 700 Hz and 20 kHz.
As mentioned previously in this document, two species of cetacean,
bottlenose and Atlantic spotted dolphins, are likely to occur in the
project area. These two species are both classified as mid-frequency
cetaceans (Southall et al., 2007).
Potential Effects of the Specified Activity on Marine Mammals
Potential effects of Port Dolphin's proposed port construction and
subsequent operations are likely to be acoustic in nature. In-water
construction activities (e.g., pile driving, pipeline installation) and
LNG port operations introduce sound into the marine environment and
have the potential to have adverse impacts on marine mammals. The
potential effects of sound from the proposed activities associated with
the Port might include one or more of the following: Tolerance, masking
of natural sounds, behavioral disturbance, non-auditory physical
effects, and temporary or permanent hearing impairment (Richardson et
al., 1995). However, for reasons discussed later in this document, Port
Dolphin's activities would not likely cause any cases of non-auditory
physical effects or temporary or permanent hearing impairment. As
outlined in previous NMFS documents, the effects of sound on marine
mammals are highly variable and can be categorized as follows (based on
Richardson et al., 1995):
The sound may be too weak to be heard at the location of
the animal (i.e., lower than the prevailing ambient sound level, the
hearing threshold of the animal at relevant frequencies, or both);
The sound may be audible but not strong enough to elicit
any overt behavioral response;
The sound may elicit reactions of varying degrees and
variable relevance to the well-being of the marine mammal. Reactions
can range from temporary alert responses to active avoidance reactions
such as vacating an area until the stimulus ceases, but potentially for
longer periods of time;
Upon repeated exposure, a marine mammal may exhibit
diminishing responsiveness (habituation), or disturbance effects may
persist; the latter is most likely with sounds that are highly variable
in characteristics and unpredictable in occurrence, and associated with
situations that a marine mammal perceives as a threat;
Any anthropogenic sound that is strong enough to be heard
has the potential to result in masking, or reduce the ability of a
marine mammal to hear biological sounds at similar frequencies,
including calls from conspecifics and underwater environmental sounds
such as surf sound;
If mammals remain in an area for feeding, breeding, or
some other biologically important purpose even though there is chronic
exposure to sound, the possibility exists for sound-induced
physiological stress; this might
[[Page 55662]]
in turn have negative effects on the well-being or reproduction of the
animals involved; and
Very strong sounds have the potential to cause a temporary
or permanent reduction in hearing sensitivity, also referred to as
threshold shift. In terrestrial mammals, and presumably marine mammals,
received sound levels must far exceed the animal's hearing threshold
for there to be any temporary threshold shift (TTS). For transient
sounds, the sound level necessary to cause TTS is inversely related to
the duration of the sound. Received sound levels must be even higher
for there to be risk of permanent hearing impairment (PTS). In
addition, intense acoustic or explosive events may cause trauma to
tissues associated with organs vital for hearing, sound production,
respiration, and other functions. This trauma may include minor to
severe hemorrhage.
Tolerance
Numerous studies have shown that underwater sounds from industrial
activities are often readily detectable by marine mammals in the water
at distances of many kilometers. However, other studies have shown that
marine mammals at distances more than a few kilometers away often show
no apparent response to industrial activities of various types (Miller
et al. 2005). This is often true even in cases when the sounds must be
readily audible to the animals based on measured received levels and
the hearing sensitivity of that mammal group. Although various baleen
whales, toothed whales, and (less frequently) pinnipeds have been shown
to react behaviorally to underwater sound from sources such as airgun
pulses or vessels under some conditions, at other times, mammals of all
three types have shown no overt reactions (e.g., Malme et al., 1986;
Richardson et al., 1995; Madsen and Mohl, 2000; Croll et al., 2001;
Jacobs and Terhune, 2002; Madsen et al., 2002; Miller et al., 2005). In
general, small odontocetes seem to be more tolerant of exposure to some
types of underwater sound than are baleen whales.
Masking
Masking is the obscuring of sounds of interest to an animal by
other sounds, typically at similar frequencies. Marine mammals are
highly dependent on sound, and their ability to recognize sound signals
amid other sound is important in communication and detection of both
predators and prey. Background ambient sound may interfere with or mask
the ability of an animal to detect a sound signal even when that signal
is above its absolute hearing threshold. Even in the absence of
anthropogenic sound, the marine environment is often loud. Natural
ambient sound includes contributions from wind, waves, precipitation,
other animals, and thermal sound, at frequencies above 30 kHz,
resulting from molecular agitation (Richardson et al., 1995).
In general, masking effects are expected to be less severe when
sounds are transient than when they are continuous. The majority of
sound produced during the construction of Port Dolphin would be
transient. Masking is typically of greater concern for those marine
mammals that utilize low-frequency communications, such as baleen
whales and, as such, is not likely to occur for the mid-frequency
cetaceans in the project area.
Disturbance
Behavioral disturbance is one of the primary potential impacts of
anthropogenic sound on marine mammals. Disturbance can result in a
variety of effects, such as subtle or dramatic changes in behavior or
displacement but may be highly dependent upon the context in which the
potentially disturbing stimulus occurs. For example, an animal that is
feeding may be less prone to disturbance from a given stimulus than one
that is not. For many species and situations, there is no detailed
information about reactions to sound. While there are no specific
studies of the reactions of marine mammals to sounds produced by the
construction or operation of a LNG facility, information from studies
of marine mammal reactions to other types of continuous and transient
anthropogenic sound (e.g., drillships) are described here as a proxy.
Behavioral reactions of marine mammals to sound are difficult to
predict because they are dependent on numerous factors, including
species, maturity, experience, activity, reproductive state, time of
day, and weather. If a marine mammal does react to an underwater sound
by changing its behavior or moving a small distance, the impacts of
that change may not be important to the individual, the stock, or the
species as a whole. However, if a sound source displaces marine mammals
from an important feeding or breeding area for a prolonged period,
impacts on the animals could be important.
Based on the literature reviewed in Richardson et al. (1995), most
small and medium-sized toothed whales exposed to prolonged or repeated
underwater sounds are unlikely to be displaced unless the overall
received level is at least 140 dB, although the limited available data
indicate that the sperm whale is sometimes, though not always, more
responsive to underwater sounds than other toothed whales. Baleen
whales, with better hearing sensitivities at lower sound frequencies,
have been shown in several studies to react to continuous sounds at
received sound levels of approximately 120 dB. Toothed whales appear to
exhibit a greater variety of reactions to anthropogenic underwater
sound than do baleen whales. Toothed whale reactions can vary from
attraction (e.g., bow riding) to strong avoidance, while baleen whale
reactions range from neutral (little or no change in behavior) to
strong avoidance. Potential disturbance reactions of odontocetes are
discussed in somewhat more detail.
In their comprehensive literature review, Southall et al. (2007)
reported that combined field and laboratory data for mid-frequency
cetaceans exposed to non-pulse sounds did not lead to clear conclusions
about behavioral responses that may be expected from given received
levels of sound. In some settings, individuals in the field showed
significant behavioral responses to exposures from 90 to 120 dB, while
others failed to exhibit such responses for exposure to received levels
from 120 to 150 dB. Species differences, as well as uncontrolled
contextual variables other than exposure, are the likely reasons for
this variability. Captive subjects were often directly reinforced with
food for tolerating exposure to high levels of sound, which likely
explains the disparity seen in results from field and laboratory
settings--where exposures typically exceeded 170 dB before inducing
behavioral responses.
Dolphins and other toothed whales may show considerable tolerance
of floating and bottom-founded drill rigs and their support vessels,
though reactions are variable. Kapel (1979) reported that pilot whales
congregated within visual range of drillships and their support vessels
off of Greenland. Beluga whales (Delphinapterus leucas) have been
observed swimming within 100-150 m (328-492 ft) of an artificial island
while drilling was underway and within 1 mi (1.6 km) of a drillship
engaged in active drilling (Fraker and Fraker, 1979, 1981). However,
other belugas, when exposed to playbacks of drilling sounds, showed
avoidance reactions, including altering course, increased swimming
speed, and reversed direction of travel (Stewart et al., 1982;
Richardson et al., 1995). Reactions of beluga whales to semi-
submersible drillship sound were less
[[Page 55663]]
pronounced than were their reactions to motorboats with outboard
engines (Thomas et al., 1990). There may be a significant contextual
element to these reactions.
Morton and Symonds (2002) used census data on killer whales in
British Columbia to evaluate avoidance of non-pulse acoustic harassment
devices (AHDs). Avoidance ranges around the AHDs were about 2.5 mi (4
km). Also, there was a dramatic reduction in the number of days
resident killer whales were sighted during AHD-active periods compared
to pre- and post-exposure periods and a nearby control site.
Some species of small toothed whales avoid vessels when they are
approached to within 0.5-1.5 km (0.31-0.93 mi), with occasional reports
of avoidance at greater distances (Richardson et al., 1995). Some
toothed whale species, especially beaked whales and belugas, appear to
be more responsive than others. However, dolphins may tolerate vessels
of all sizes, often approaching and riding the bow and stern waves
(Shane et al., 1986). At other times, dolphin species that are known to
be attracted to vessels will avoid them. Such avoidance is often linked
to previous vessel-based harassment of the animals (Richardson et al.,
1995). Coastal bottlenose dolphins that are the object of dolphin-
watching activities have been observed to swim erratically (Acevedo,
1991), remain submerged for longer periods of time (Janik and Thompson,
1996; Nowacek et al., 2001), display less cohesiveness among group
members (Cope et al., 1999), whistle more frequently (Scarpaci et al.,
2000), and rest less often (Constantine et al., 2004) when vessels were
nearby. Pantropical spotted dolphins and spinner dolphins in the
Eastern Tropical Pacific, where they have been targeted by commercial
fishing vessels because of their association with tuna, display
avoidance of survey vessels of up to 11.1 km (6.9 mi; Au and Perryman,
1982; Hewitt, 1985), whereas spinner dolphins in the GOM were observed
bow riding the survey vessel in all fourteen sightings during one
survey (W[uuml]rsig et al., 1998). As evidenced by these observations,
the level of response of odontocetes to vessels is thought to be partly
a learned behavior, e.g., a function of habituation or a response to
some previous negative interaction.
Hearing Impairment and Other Physiological Effects
Temporary or permanent hearing impairment is a possibility when
marine mammals are exposed to very strong sounds. Non-auditory
physiological effects might also occur in marine mammals exposed to
strong underwater sound. Possible types of non-auditory physiological
effects or injuries that may occur in mammals close to a strong sound
source include stress, neurological effects, bubble formation, and
other types of organ or tissue damage. Some marine mammal species
(e.g., beaked whales) may be especially susceptible to injury and/or
stranding when exposed to strong pulsed sounds, particularly at higher
frequencies. Non-auditory physiological effects are not anticipated to
occur as a result of the proposed activities, which largely do not
include strong pulsed sounds. The following subsections discuss in more
detail the possibilities of TTS and PTS.
TTS--TTS, reversible hearing loss caused by fatigue of hair cells
and supporting structures in the inner ear, is the mildest form of
hearing impairment that can occur during exposure to a strong sound
(Kryter, 1985). While experiencing TTS, the hearing threshold rises,
and a sound must be stronger in order to be heard. TTS can last from
minutes or hours to (in cases of strong TTS) days. For sound exposures
at or somewhat above the TTS threshold, hearing sensitivity in both
terrestrial and marine mammals recovers rapidly after exposure to the
sound ends.
NMFS considers TTS to be a form of Level B harassment rather than
injury, as it consists of fatigue to auditory structures rather than
damage to them. The NMFS-established 180-dB injury criterion is
considered to be the received level above which, in the view of a panel
of bioacoustics specialists convened by NMFS before TTS measurements
for marine mammals became available, one could not be certain that
there would be no injurious effects, auditory or otherwise, to
cetaceans. Few data on sound levels and durations necessary to elicit
mild TTS have been obtained for marine mammals, and none of the
published data concern TTS elicited by exposure to multiple pulses of
sound.
Human non-impulsive sound exposure guidelines are based on
exposures of equal energy (the same sound exposure level [SEL]; SEL is
reported here in dB re: 1 [mu]Pa\2\-s for in-water sound) producing
equal amounts of hearing impairment regardless of how the sound energy
is distributed in time (NIOSH, 1998). Until recently, previous marine
mammal TTS studies have also generally supported this equal energy
relationship (Southall et al., 2007). Three newer studies, two by
Mooney et al. (2009a,b) on a single bottlenose dolphin either exposed
to playbacks of U.S. Navy mid-frequency active sonar or octave-band
sound (4-8 kHz) and one by Kastak et al. (2007) on a single California
sea lion exposed to airborne octave-band sound (centered at 2.5 kHz),
concluded that for all sound exposure situations, the equal energy
relationship may not be the best indicator to predict TTS onset levels.
Generally, with sound exposures of equal energy, quieter sound
exposures (lower SPL) with longer duration were found to induce TTS
onset more than those of louder (higher SPL) and shorter duration.
Given the available data, the received level of a single seismic pulse
(with no frequency weighting) might need to be approximately 186 dB SEL
in order to produce brief, mild TTS.
Data on TTS from continuous sound (such as that produced by Port
Dolphin's proposed activities) are limited, so the available data from
seismic activities are used as a proxy. Exposure to several strong
seismic pulses that each have received levels near 175-180 dB SEL might
result in slight TTS in a small odontocete, assuming the TTS threshold
is (to a first approximation) a function of the total received pulse
energy. Given that the SPL is approximately 10-15 dB higher than the
SEL value for the same pulse, an odontocete would need to be exposed to
a SPL of 190 dB in order to incur TTS.
TTS was measured in a single, captive bottlenose dolphin after
exposure to a continuous tone with maximum SPLs at frequencies ranging
from 4 to 11 kHz that were gradually increased in intensity to 179 dB
and in duration to 55 minutes (Nachtigall et al., 2003). No threshold
shifts were measured at SPLs of 165 or 171 dB. However, at 179 dB, TTSs
greater than 10 dB were measured during different trials with exposures
ranging from 47 to 54 minutes. Hearing sensitivity apparently recovered
within 45 minutes after sound exposure.
Although underwater sound levels produced by the Port Dolphin
project may exceed levels produced in studies that have induced TTS in
odontocetes, there is a general lack of controlled, quantifiable field
studies related to this phenomenon, and existing studies have had
varied results (Southall et al., 2007). Therefore, it is difficult to
extrapolate from these data to site-specific conditions for the Port
Dolphin project. For example, because most of the studies have been
conducted in laboratories, rather than in field settings, the data are
not conclusive as to whether elevated levels of sound will cause
odontocetes to avoid the project area, thereby reducing the likelihood
of TTS, or whether sound will attract them, increasing the likelihood
of TTS. In any case, there are no universally
[[Page 55664]]
accepted standards for the amount of exposure time likely to induce
TTS. While it may be inferred that TTS could theoretically result from
the proposed activities, it is impossible to exactly quantify the
magnitude of exposure, the duration of the effect, or the number of
individuals likely to be affected. Exposure is likely to be brief
because the majority of proposed activities would be transient. It is
expected that elevated sound would have only a negligible probability
of causing TTS in individual odontocetes because (1) of the relatively
low SPLs produced by most project activities; (2) the transient nature
of most sounds produced by the activities; (3) the short duration of
certain activities that are expected to produce higher SPLs (i.e.,
offshore pile driving); and (4) the location of the project in,
primarily, offshore open waters where marine mammals may easily avoid
areas of ensonification.
PTS--When PTS occurs, there is physical damage to the sound
receptors in the ear. In some cases, there can be total or partial
deafness, whereas in other cases the animal has an impaired ability to
hear sounds in specific frequency ranges.
There is no specific evidence that exposure to underwater
industrial sounds can cause PTS in any marine mammal (see Southall et
al., 2007). However, given the possibility that marine mammals might
incur TTS, there has been further speculation about the possibility
that some individuals occurring very close to industrial activities
might incur PTS. Richardson et al. (1995) hypothesized that PTS caused
by prolonged exposure to continuous anthropogenic sound is unlikely to
occur in marine mammals, at least for sounds with source levels up to
approximately 200 dB. Single or occasional occurrences of mild TTS are
not indicative of permanent auditory damage in terrestrial mammals.
Relationships between TTS and PTS thresholds have not been studied in
marine mammals but are assumed to be similar to those in humans and
other terrestrial mammals. PTS might occur at a received sound level at
least several decibels above that inducing mild TTS.
Southall et al. (2007) propose that sound levels inducing 40 dB of
TTS may result in onset of PTS in marine mammals. The authors present
this threshold with precaution, as there are no specific studies to
support it. Because direct studies on marine mammals are lacking, the
authors base these recommendations on studies performed on other
mammals. Additionally, the authors assume that multiple pulses of
underwater sound result in the onset of PTS in mid-frequency cetaceans
when levels reach 230 dB peak or 198 dB SEL; non-pulsed (continuous)
sound would require levels of 230 dB peak or 215 dB SEL (Southall et
al., 2007). Sound levels this high are not expected to occur as a
result of the proposed activities.
The potential effects to marine mammals described in this section
of the document do not take into consideration the proposed monitoring
and mitigation measures described later in this document (see the
PROPOSED MITIGATION and PROPOSED MONITORING AND REPORTING sections).
Because of the characteristics of sound produced by most construction
activities (i.e., they are typically low intensity, non-pulsed, and
transient), it is highly unlikely that marine mammals would receive
sounds strong enough (and over a sufficient duration) to cause PTS (or
even TTS). When taking the mitigation measures proposed for inclusion
in the regulations into consideration (e.g., shutdown zones to prevent
Level A harassment), it is highly unlikely that any type of hearing
impairment would occur as a result of the proposed activities.
Anticipated Effects on Habitat
The proposed activities could have some impacts on marine mammal
habitat, primarily by producing temporary disturbances through elevated
levels of underwater sound, and to a lesser extent, temporarily reduced
water quality and temporary and permanent physical habitat alteration.
These impacts would not be expected to have tangible direct effects to
marine mammals, but could result in minor effects to fish or other
elements of the marine mammal prey base. Elevated levels of sound may
be considered to affect the habitat of marine mammals through impacts
to acoustic space (described in previous sections) or via impacts to
prey species. The direct loss of habitat available during construction
due to sound impacts is expected to be minimal.
Seafloor Disturbance
Installation of port components and pipelines would cause short-
and long-term disruption of benthic habitat in the immediate vicinity
of the construction areas; permanent alteration of benthic habitat
would result from buoy anchor sweep during port operations. Destruction
of bottom habitat, along with resident benthic organisms within the
area, is an unavoidable component of pipeline installation. This
affects not only the benthic communities, but also the fish assemblages
that rely on those communities for food and/or shelter; these fish may
in turn be preyed upon by marine mammals. Immediately upon cessation of
disturbance, the substrate would be available for recruitment of
benthic organisms and reestablishment of the community.
The areas affected by seafloor disturbance are essentially
negligible in comparison with the habitat available to marine mammals
in the surrounding area. The pipeline route was selected to avoid
marine protected areas and areas of submerged aquatic vegetation to the
extent possible. During and shortly after installation of the buoy
array components and the pipeline, marine mammal prey species are
expected to avoid feeding in the immediate vicinity of the project
area, thus reducing the utility of habitat in the area. Displaced
organisms would likely return to the area shortly after construction
activities cease.
Turbidity
Turbidity refers to any insoluble particulate matter suspended in
the water column that impedes light passage by scattering and absorbing
light energy. Decreased light penetration reduces the depth of the
photic zone, in turn reducing the depth at which primary productivity
could occur. Impacts to marine mammals would be indirect, resulting
from impacts to prey species. Water turbidity appears to have little or
no direct impact on bottlenose dolphins, which are regularly seen in
turbid waters. Turbidity may adversely affect prey species by direct
mortality or reduction of growth rates, modifying migration patterns,
reducing available food abundance or habitat (in part by reducing
primary production), or burial of benthic shellfish.
However, these potential impacts would be spatially limited and
short-term in nature, as the suspended sediment would redeposit soon
after the buoy system array and pipeline components were installed.
Seawater Intake and Discharge
During the construction phase, seawater would be used for
hydrostatic testing of the offshore pipeline and flowlines. Hydrostatic
testing is a one-time temporary event that would require filling the
pipeline twice; a total of approximately 24 million gallons would be
used. Hydrostatic integrity testing could nevertheless indirectly
impact marine mammals, because plankton and fish larvae and eggs could
be entrained and subsequently killed by the seawater intake system.
This could have either primary or secondary indirect impacts
[[Page 55665]]
on marine mammals through impacts to prey species.
During regasification, seawater would be taken into an SRV through
one of two sea chests covered with a lattice screen. Similar to uptake
described for hydrostatic testing, marine mammals may be indirectly
impacted through the entrainment of plankton and fish eggs and larvae.
Cooling water would be discharged at 10 [deg]C (18[emsp14][deg]F) above
ambient seawater temperature, and would affect a relatively small area.
The discharge would produce detectable temperature increases over a
maximum radius of 106 m (348 ft). The cooling water discharge is not
expected to reach the seafloor, and would thus not impact benthic
communities. The cooling water plume would affect a relatively small
area. Considering the short-term nature of impacts and the overall
amount of plankton and fish eggs and larvae in the area, these impacts
may be considered negligible.
Sound Disturbance
Elevated levels of sound produced by port construction and
operation could potentially directly impact marine mammals by reducing
the attractiveness of a given area for foraging, i.e., marine mammals
may be less likely to forage in a given area in the presence of
elevated levels of sound. In addition, sound may indirectly impact
marine mammals through effects to fish or other prey species. However,
sound produced by project activities is unlikely to be of sufficient
intensity or duration to result in significant pathological,
physiological, or behavioral effects to fish.
All of the potential adverse impacts to marine mammal habitat would
likely be indirect, and would result from impacts on the food web
(i.e., adverse impacts directly to marine mammal prey species or to
species lower in the food chain) from the proposed activities. The
impact to marine mammals of temporary and permanent habitat changes
from the proposed activities is expected to be minimal. Any potential
impacts would likely be negligible relative to the amount of habitat
available on the west Florida Shelf or in adjacent nearshore waters.
These effects are summarized here:
Seafloor disturbance and turbidity: Marine mammals could
be indirectly impacted if benthic prey species were displaced or
destroyed. Affected species would be expected to recover after
construction ceased, and would represent only a small portion of food
available to marine mammals in the area. Indirect adverse impacts of
limited spatial extent could occur as a result of short- and long-term
turbidity increases caused by construction and operations.
Seawater intake and discharge: This activity, primarily
occurring during regasification, would result in the entrainment and
destruction of plankton and larvae and discharge of heated seawater.
The resulting adverse impact to the prey base would be negligible.
Sound disturbance: Elevated levels of sound during
construction would cause temporary modification of habitat and could
harm prey species, potentially reducing utility of habitat for marine
mammal foraging. Elevated levels of sound during operation of the DWP
would result in essentially permanent habitat modification to a limited
area in the immediate vicinity of each STL buoy.
In conclusion, NMFS has preliminarily determined that Port
Dolphin's proposed activities are not expected to have any habitat-
related effects that could cause significant or long-term consequences
for individual marine mammals or on the food sources that they utilize.
Proposed Mitigation
In order to issue an incidental take authorization under section
101(a)(5)(A) of the MMPA, NMFS must, where applicable, set forth the
permissible methods of taking pursuant to such activity, and other
means of effecting the least practicable adverse impact on such species
or stock and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of such species or stock for taking for certain
subsistence uses (where relevant). NMFS and Port Dolphin worked to
devise a number of mitigation measures designed to minimize impacts to
marine mammals to the level of least practicable adverse impact,
described in the following and in Port Dolphin's Marine Protected
Species Management Plan; please see Appendix B of Port Dolphin's
application to review that plan in detail.
In addition to the measures described later, Port Dolphin would
employ the following standard mitigation measures:
All work would be performed according to the requirements
and conditions of the regulatory permits issued by federal, state, and
local governments.
Briefings would be conducted between the Port Dolphin
project construction supervisors and the crew, protected species
observer(s) (PSO), and acoustical monitoring team (when present) prior
to the start of all discrete construction activities, and when new
personnel join the work, to explain responsibilities, communication
procedures, marine mammal monitoring protocol, and operational
procedures.
Port Dolphin would comply with all applicable equipment
sound standards and ensure that all construction equipment has sound
control devices no less effective than those provided on the original
equipment. In addition, vessel crew and contractors would be required
to minimize sound to the extent possible. Equipment and/or procedures
used may include the use of enclosures and mufflers on equipment,
minimizing the use of thrusters, and turning off engines and equipment
when not in use.
Additional mitigation measures, which are discussed in greater
detail below, include the following:
Visual monitoring program (marine mammal watch);
Vessel strike avoidance measures;
Line and cable entanglement avoidance measures; and
Marine debris and waste management protocols.
Monitoring and Shutdown
The modeling results for acoustic zones of influence (ZOIs;
described in following sections) were used to develop mitigation
measures for the proposed activities. Those zones would initially be
set at the distances derived through modeling (or be larger than those
distances), but may be adjusted as necessary on the basis of acoustic
monitoring conducted by Port Dolphin in order to verify source levels
and local acoustic propagation characteristics (see Proposed Monitoring
and Reporting, later in this document). The ZOIs effectively represent
the mitigation zone that would be established around each activity to
prevent Level A harassment and to monitor authorized Level B harassment
of marine mammals.
For each of the described proposed activities, a shutdown zone (to
include areas where SPLs equal or exceed 180 dB rms) and a disturbance
zone (defined as where SPLs equal or exceed 120 dB or 160 dB rms for
non-pulsed or pulsed sound sources, respectively) would be established.
Shutdown zones include all areas where the underwater SPLs are
anticipated to equal or exceed the Level A (injury) harassment criteria
for marine mammals and are used in concert with mitigation monitoring
in order to prevent the occurrence of Level A harassment. Disturbance
zones typically include all areas where the underwater SPLs are
anticipated to equal or exceed the Level B (behavioral) harassment
criteria. These are intended as zones in which occurrence of marine
mammals would be noted and recorded as
[[Page 55666]]
incidental take while also alerting PSOs to potential close approach to
the shutdown zone. In actual practice, the disturbance zones are often
so large as to make comprehensive monitoring and fine-scale behavioral
observation impracticable. The initial shutdown and disturbance zones
would be established based on the worst-case underwater sound modeled
as described, although shutdown zones may be larger than the actual
modeled distances. Please see the discussion of ``Distance to Sound
Thresholds'' under ``Description of Sound Sources,'' previously in this
document.
Conservative shutdown zones would be employed in most instances.
Impact pile driving (described later) and non-stationary activities
would employ zones larger than what is predicted for the Level A
harassment threshold. Radial distances to shutdown zones for HDD
activities were predicted to be less than 10 m. For all activities, and
regardless of modeled shutdown zone (applicable to HDD activities), all
equipment would be shut down if any marine mammal enters a
precautionary 100 yd (91 m) zone in order to avoid potential risk of
vessel strike or direct interaction with equipment. However, these
shutdown requirements would not be required for cases in which
delphinids voluntarily make such close approaches to vessels (e.g., for
bow riding). In addition, for scenarios in which the modeled sound
source is a spread of vessels employed for a given construction task,
the shutdown/disturbance zone would be measured from the central vessel
in the spread, or the vessel that is the primary sound producer if it
is not the central vessel. In most cases, the disturbance zone is of
sufficient size to make comprehensive monitoring impracticable,
although PSOs would be aware of the size and location of the modeled
zone and would record any observations made within the zone as takes.
Radial distances to Level B thresholds range up to 12.6 km; please
refer to Table 6 for those distances.
Monitoring Protocols
The established zones would be monitored by qualified PSOs for
mitigation purposes, as described here. Port Dolphin's marine mammal
monitoring plan (see Appendix B of Port Dolphin's application) would be
implemented, requiring collection of sighting data for each marine
mammal observed during the proposed construction activities described
in this document.
At least two PSOs would conduct monitoring of shutdown and
disturbance zones (as described previously) for all concurrent
specified construction activities during daylight hours (civil dawn to
civil dusk). PSOs would have no other duties for the duration of the
watch. Shutdown and disturbance zones would be monitored from an
appropriate vantage point that affords the PSOs an optimal view of the
sea surface while not interfering with operation of the vessel or
in[hyphen]water activities. Full observation of the shutdown zone would
occur for the duration of the activity.
Monitoring would occur before, during, and after specified
construction activity, beginning 30 minutes prior to initiation and
concluding 30 minutes after the activity ends. If marine mammals are
present within the shutdown zone prior to initiation, the start would
be delayed until the animals leave the shutdown zone of their own
volition, or until 30 minutes elapse without resighting the animal(s).
PSOs will be on watch at all times during daylight hours when
in[hyphen]water operations are being conducted, unless conditions
(e.g., fog, rain, darkness) make observations impossible. If conditions
deteriorate during daylight hours such that the sea surface
observations are halted, visual observations must resume as soon as
conditions permit. While activities will be permitted during low-
visibility conditions, they (1) must have been initiated following
proper clearance of the ZOI under acceptable observation conditions;
and (2) must be restarted, if halted for any reason, using the
appropriate ZOI clearance procedures.
If a marine mammal is observed approaching or entering the shutdown
zone, the PSO will call for the immediate shutdown of in[hyphen]water
operations. The equipment operator must comply with the shutdown order
unless human safety is at risk. Any disagreement must be resolved after
the shutdown takes place. Construction operations would be discontinued
until the animal has moved outside of the shutdown zone. The animal
would be determined to have moved outside the shutdown zone through
visual confirmation by a qualified PSO or after 15 minutes have elapsed
since the last sighting of the animal within the shutdown zone. The
following additional measures would apply to visual monitoring:
Monitoring would be conducted using binoculars and the
unaided eye. The limits of the designated ZOI will be determined using
binocular reticle or other equipment (e.g., electronic rangefinder,
range stick). A GPS unit or range finder would be used for determining
the observation location and distance to marine mammals and sound
sources.
Each PSO would have a dedicated two-way radio for contact
with the other PSO or field operations manager.
Whenever a marine mammal species is observed, the PSO will note and
monitor the position (including relative bearing and estimated distance
to the animal) until the animal dives or moves out of visual range of
the PSO. The PSO will continue to observe for additional animals that
may surface in the area. Often, there are numerous animals that may
surface at varying time intervals. Records will be maintained of all
marine mammal species sightings in the area, including date and time,
weather conditions, species identification, approximate distance from
the activity, direction and heading in relation to the activity, and
behavioral correlation to the activity. For animals observed in the
shutdown zone, additional information regarding actions taken, such as
duration of the shutdown, behavior of the animal, and time spent in the
shutdown zone will be recorded. During pile driving activities, data
regarding the type of pile driven (e.g., material construction and pile
dimensions), type and power of the hammer used, number of cold starts,
strikes per minute, and duration of the pile driving activities will be
recorded.
Monitoring would be conducted by qualified PSOs. In order to be
considered qualified, PSOs must meet the following criteria:
Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target.
Advanced education in biological science, wildlife
management, mammalogy, or related fields (bachelor's degree or higher
is required).
Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience).
Experience or training in the field identification of
marine mammals, including the identification of behaviors.
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations.
Writing skills sufficient to prepare a report of
observations, including, but not limited to, the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and
[[Page 55667]]
times when in-water construction activities were suspended to avoid
potential incidental injury from construction sound of marine mammals
observed within a defined shutdown zone; and marine mammal behavior.
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Pile Driving
Mitigation measures specific to pile driving would include use of
(1) a sound attenuation device and (2) ramp-up procedures. In addition,
the power of impact hammers will be reduced to minimum energy levels
required to drive a pile, thus reducing the amount of sound produced in
the marine environment. As for other construction activities, vibratory
pile driving may continue into nighttime hours/low-visibility
conditions only if ramp-up protocols have been conducted under
acceptable observation conditions. Impact pile driving may occur only
during daylight hours of good visibility. In the event of a shutdown
during low-visibility conditions, the pile driving cannot resume until
visual monitoring activities are resumed under acceptable observation
conditions. The minimum shutdown zone for impact pile driving would be
established conservatively at 250 m.
One or more sound attenuation device will be utilized during all
impact pile driving activities needed to install components of the STL
buoys at the deepwater port. The sound attenuation device(s) will be
selected and designed by the marine construction and design
contractor(s), but would likely be either a bubble curtain or a
temporary sound attenuation pile (TNAP), potentially used in
conjunction with cushion block. Please see the discussion of ``Sound
Attenuation Devices'' under ``Description of Sound Sources,''
previously in this document.
The objective of a ramp-up is to alert any animals close to the
activity and allow them time to move away, which would expose fewer
animals to loud sounds. This procedure also ensures that any marine
mammals missed during shutdown zone monitoring would move away from the
activity and not be injured. The following ramp-up procedures would be
used for in-water pile installation:
To allow any marine mammals that may be in the immediate
area to leave before pile driving reaches full energy, a ramp-up
technique would be used at the beginning of each day's in-water pile
driving activities or if pile driving has ceased for more than 1 hour.
If a vibratory driver is used, contractors would be
required to initiate sound from vibratory hammers for 15 seconds at
reduced energy followed by a 1-minute waiting period. The procedure
would be repeated two additional times before full energy may be
achieved.
If a non-diesel impact hammer is used, contractors would
be required to provide an initial set of strikes from the impact hammer
at reduced energy, followed by a 1-minute waiting period, then two
subsequent sets.
If a diesel impact hammer is used, contractors would be
required to turn on the sound attenuation device (e.g., bubble curtain
or other approved sound attenuation device) for 15 seconds prior to
initiating pile driving to flush marine mammals from the area.
Vessel Strike Avoidance
Several construction and support vessels will be used during
offshore construction activities. Certain vessel activities, including
transits, may not be subject to the visual monitoring and shutdown
protocols described previously in this section. Consequently, there is
the possibility for vessel strike of protected species to occur within
the project area. Port Dolphin would inform all personnel associated
with the project of the potential presence of protected species. All
vessel crew members and contractors would participate in training for
protected species presence and emergency procedures in the unlikely
event a protected species is struck by a vessel. Construction and
support vessels will follow the NMFS Vessel Strike Avoidance Measures
and Reporting for Mariners. Standard measures would be implemented to
reduce the risk associated with vessel strikes.
The following vessel strike mitigation measures for cetaceans for
active construction/installation vessel operations would be implemented
during project activities:
Vessel operators and crews must maintain a vigilant watch
for marine mammals and slow down or stop their vessels, to the extent
possible as dictated by safety concerns, to avoid striking sighted
protected species.
Construction or support vessels, while underway, would
remain 100 yd (91 m) from all marine mammals to the extent possible.
If a marine mammal is within 15 m of a construction or
support vessel underway, all operations will cease until it is > 100 yd
from the vessel. If the marine mammal is observed within 100 yd of an
active construction or support vessel underway, the vessel would cease
power to the propellers as long as sea conditions permit for safety.
After the marine mammal leaves the area the vessel would proceed with
caution, following the guidelines below:
[ssquf] Resume vessel at slow speeds while avoiding abrupt changes
in direction,
[ssquf] Stay on parallel course with the marine mammal, following
behind or next to at an equal or lesser speed,
[ssquf] Do not cross the path of the animal,
[ssquf] Do not attempt to steer or direct the marine mammal away,
[ssquf] If a marine mammal exhibits evasive or defensive behavior,
stop the vessel until the marine mammal has left the immediate area,
and
[ssquf] Do not allow the vessel to come between a mother and her
calf.
Cetaceans can surface in unpredictable locations or
approach slowly moving vessels. When an animal is sighted in the
vessel's path or in close proximity to a moving vessel, the Master
would reduce speed and shift the engine to neutral and would not engage
the engines until the animals are clear of the area.
If a sighted marine mammal is believed to be a North
Atlantic right whale, federal regulation requires a minimum distance of
500 yd (457 m) from the animal be maintained (50 CFR 224.103 (c)).
Practical speeds would be maintained to the extent
possible. Guidelines for speeds include the following:
[ssquf] Reduce vessel speed to 10 kn or less when mother/calf
pairs, pods, or large assemblages of cetaceans are observed near an
underway vessel, when safety permits. A single cetacean at the surface
can indicate the presence of submerged animals in the vicinity of the
vessel; therefore, prudent precautionary measures should always be
exercised.
[ssquf] No wake/idle speeds where the draft of the vessel provides
less than a 4-ft (1.2-m) clearance from the bottom. All vessels would
follow deep-water routes whenever possible.
[ssquf] All construction vessels transiting to and from the port
from shore would not exceed 14 kn during regular operations.
[ssquf] Avoid sudden changes in speed and direction.
[ssquf] Speeds approaching and departing the buoys would be reduced
to 10 kn maximum.
[ssquf] Speeds during installation would be well under 14 kn;
vessels may be stationary during certain phases of installation.
If a collision seems likely, emergency collision
procedures would be followed.
[[Page 55668]]
Members of the vessel crew would be encouraged to undergo
NMFS training prior to activity, including instruction in reporting
procedures, collision emergency procedures, and marine mammal presence
detection (surfacing near wake).
During construction of the facility, an Environmental
Coordinator would be on site and responsible for communicating with
NMFS and other relevant agencies, as appropriate.
During construction/installation, transiting vessels would
have lookouts required to scan for surfacing marine mammals and report
sightings to the Master, who would notify the Environmental
Coordinator.
Offshore vessel activities not required to implement
visual monitoring protocols described previously in this document would
be temporarily terminated if marine mammals were observed in the area
and there is the potential for harm of an individual. The Environmental
Coordinator would be called in to determine the appropriate course of
action.
Best Management Practices
Port Dolphin, in conjunction with NMFS and other regulatory
agencies, has proposed a number of BMPs that will reduce project
environmental impacts. Although these measures are not designed
specifically to reduce project impacts on marine mammals to the level
of least practicable adverse impact, they do have the effect of either
directly or indirectly reducing the potential for adverse effects to
marine mammals. These BMPs are briefly described here. See Port
Dolphin's application or Environmental Impact Statement for more
details about these measures.
Lighting--BMPs would be implemented to minimize the attraction of
marine mammals to the project area and prevent potential impacts to
protected species from nighttime lighting. Lighting would be down-
shielded to prevent unnecessary upward illumination while illuminating
the vessel decks only. To the extent possible, they would not
illuminate surrounding waters. Lighting used during all activities
would be regulated according to USCG requirements, without using
excessive wattage or quality of lights. Once an activity is completed,
all lights used only for that activity would be extinguished.
Entanglement--BMPs would be implemented to prevent entanglement in
any lines or cables or siltation barriers used in any construction
area. For example, lines, cables, and in-water barriers would not be
made of any materials in which a protected species can become entangled
(e.g., monofilament), would be properly secured, and would be regularly
monitored to avoid protected species entrapment.
Marine Debris--BMPs would be implemented to prevent potential
impacts to protected species from debris discarded within any
construction area, including mandatory marine debris training
consistent with Bureau of Ocean Energy Management, Regulation, and
Enforcement (BOEMRE) NTL 2007-G03 Marine Trash and Debris Awareness and
Elimination (http://www.gomr.boemre.gov/homepg/regulate/regs/ntls/2007NTLs/07-g03.pdf).
Turbidity--Measures related to turbidity are designed to reduce
project impacts to water quality in the marine environment. These
include requirements to reduce sediment resuspension from pipeline
trenching and burial through the use of certain technology.
Benthic Habitat
Anchor locations would be optimized to minimize impacts on
benthic habitat; avoidance zones would be identified of critical
habitat areas for placement of installation barge anchors. An anchoring
plan would be developed that would provide procedures for anchor
deployment to minimize impacts on hard- and live-bottom habitat.
Required vessels would be selected to minimize the number
and type of anchors, where possible, while still providing vessels
adequate to perform the work.
Midline buoys would be utilized to the extent practicable
on anchor chains to reduce the amount of anchor chain sweep.
A Mitigation Plan to compensate for unavoidable impacts on
hard bottom would be developed.
Pelagic Habitat--As described previously in this document, SRV
seawater intake/discharge and other vessel discharge protocols would be
designed to minimize impacts to water column habitat by reducing
seawater intake requirements, creating limits for seawater intake
velocity and discharge temperature, and reducing other vessel
discharges.
Conclusions
NMFS has carefully evaluated the applicant's proposed mitigation
measures and considered a range of other measures in the context of
ensuring that NMFS prescribes the means of effecting the least
practicable adverse impact on the affected marine mammal species and
stocks and their habitat. Our evaluation of potential measures included
consideration of the following factors in relation to one another:
The manner in which, and the degree to which, the
successful implementation of the measure is expected to minimize
adverse impacts to marine mammals;
The proven or likely efficacy of the specific measure to
minimize adverse impacts as planned; and
The practicability of the measure for applicant
implementation.
Based on our evaluation of the applicant's proposed measures and
the measures added by NMFS, NMFS has preliminarily determined that the
mitigation measures proposed by both NMFS and Port Dolphin provide the
means of effecting the least practicable adverse impact on marine
mammal species or stocks and their habitat, paying particular attention
to rookeries, mating grounds, and areas of similar significance.
The proposed rule comment period will afford the public an
opportunity to submit recommendations, views, and/or concerns regarding
this action and the proposed mitigation measures. While NMFS has
determined preliminarily that the proposed mitigation measures
presented in this document would effect the least practicable adverse
impact on the affected species or stocks and their habitat, NMFS will
consider all public comments to help inform the final decision.
Consequently, the proposed mitigation measures may be refined,
modified, removed, or added to prior to the issuance of the final rule
based on public comments received, and where appropriate, further
analysis of any additional mitigation measures.
Proposed Monitoring and Reporting
In order to issue an incidental take authorization (ITA) for an
activity, section 101(a)(5)(A) of the MMPA states that NMFS must, where
applicable, set forth ``requirements pertaining to the monitoring and
reporting of such taking.'' The MMPA implementing regulations at 50 CFR
216.104(a)(13) indicate that requests for ITAs must include the
suggested means of accomplishing the necessary monitoring and reporting
that would result in increased knowledge of the species and of the
level of taking or impacts on populations of marine mammals that are
expected to be present in the proposed action area.
Port Dolphin proposed a protected species monitoring plan in their
application (see Appendix B of Port
[[Page 55669]]
Dolphin's application). The plan may be modified or supplemented based
on comments or new information received from the public during the
public comment period. All monitoring methods identified herein have
been developed through coordination between NMFS and Port Dolphin. The
methods are based on the parties' professional judgment supported by
their collective knowledge of marine mammal behavior, site conditions,
and proposed project activities. Any modifications to this protocol
would be coordinated with NMFS. A summary of the plan, as well as the
proposed reporting requirements, is contained here.
The intent of the monitoring plan is to:
Comply with the requirements of the MMPA Letter of
Authorization as well as the ESA section 7 consultation;
Avoid injury to marine mammals through visual monitoring
of identified shutdown zones; and
To the extent possible, record the number, species, and
behavior of marine mammals in disturbance zones for the proposed
activities.
As described previously, monitoring for marine mammals would be
conducted in specific zones established to avoid or minimize effects of
elevated levels of sound created by the specified activities. Initial
shutdown and disturbance zones would be based on the applicant's
modeled values. Shutdown zones for non-stationary activities would
conform to NMFS Vessel Strike Avoidance Measures and Reporting for
Mariners (i.e., 100 yd)--a distance much larger than actual areas
ensonified to 180 dB rms or greater. However, shutdown requirements
would not be triggered upon voluntary approach by small marine mammals
(i.e., delphinids). The actual zone monitored for disturbance would be
based upon logistical considerations, as described previously in this
document, as the full disturbance zones would be so large as to make
monitoring impracticable. Zones may be modified on the basis of actual
recorded SPLs from acoustic monitoring.
Port Dolphin proposed a visual monitoring program in its
application. In cooperation with NMFS, Port Dolphin has supplemented
that plan with an acoustic monitoring program that would be conducted
primarily to verify the sound source levels and local acoustic
propagation characteristics that were assumed in the acoustic modeling.
Acoustic Monitoring
Port Dolphin would implement an acoustic monitoring program during
construction and operation of the deepwater port and appurtenant marine
facilities. Please see Port Dolphin's Sound Level Verification Plan
(see Supplemental Information) for more detail. The objectives of this
program are to: (1) Empirically measure the sound source levels
associated with project activities and verify estimated source levels
used in modelling, and (2) empirically determine ranges to relevant
threshold levels, verifying the accuracy of the acoustic propagation
model that was used to predict the size of sound fields generated by
construction and operation of the port. Ambient sound levels would also
be measured when no project activities are occurring.
Source level measurements would be made using a combination of
bottom deployed autonomous multi-channel acoustic recorders (AMARs) and
cabled acoustic data acquisition and monitoring systems (ADAMs), and
would require that accurate measurements of distance from source to the
monitoring hydrophones be made. Range measurements are required for
scaling the measured levels to a standard reference range (typically
one meter from the source). Range measurements would be performed using
a combination of GPS, radar and laser range finders. Both systems would
obtain measurements at 1.5 m (5 ft) above the sea floor, with the depth
of the hydrophones determined using collocated pressure-sensitive depth
gauges. The hydrophone depth measurement is accurate to within 1 m.
Received sound levels would be measured at pre-determined distances (as
specified here) and would be used to determine site-specific
propagation characteristics and verify ranges to the relevant sound
exposure thresholds.
The recording system would have a frequency response of 3 dB from 10 Hz to 64,000 Hz over the anticipated measurement
range of 100 dB to 220 dB (linear peak re: 1 [mu]Pa). Hydrophones with
differing sensitivities may be required at different locations
depending upon the acoustic environment and source to be measured.
Analysis of the recorded data would determine the amplitude, time
history, and frequency of sounds associated with construction activity.
Acoustic data to be reported include:
Mean squared pressure (integral of the squared pressure
for duration of impulse, divided by the impulse duration; dB re: 1
[mu]Pa\2\/s, rms) for pulsed sounds;
SPL (dB re: 1 [mu]Pa, rms) for non-pulsed sounds;
The maximum averaging time and representative range of
SPLs;
Representative range of frequency spectra; 1/3rd octave
band center frequency SPLs dB re:1 [mu]Pa measured over the frequency
range of 10 Hz to 64,000 Hz; and
Peak SPL (dB re: 1 [mu]Pa; the largest absolute value of
the instantaneous sound pressure over the minimum frequency range of 10
Hz to 64,000 Hz). The maximum and representative range of peak SPLs
would be recorded for each activity.
The activities to be monitored are:
Pipelaying activities;
Pipeline burial using the plow system and dredging;
Pile driving at the buoy locations;
Installation of the STL buoys;
HDD within Tampa Bay;
Vibratory driving (if conducted); and
SRV maneuvering and docking.
Verification of sound source levels emitted by each of the various
activities is required. Although most types of construction activity
would be conducted at more than one location and on more than one
occasion during the construction period, it is only necessary to
determine their sound source level once because local acoustic
propagation characteristics should have little effect on the source
level calculation. Some construction activities are of long duration
and may vary in source level during the operation. For these longer-
duration activities (i.e., pipelaying and burial, HDD), a sound level
monitoring program of 7 days of continuous recording at a sample rate
of 128 kHz would be implemented to capture and consider potential
variability when determining the source level associated with these
activities. During the 7-day program, logs of the various activities
would be collected, permitting a correlation between the activities
occurring and the sound levels recorded. For all construction
activities, sound level monitoring stations would consist of bottom
deployed autonomous recorders at ranges of 500, 1,000 and 1,500 m,
perpendicular to the construction spread's direction of travel when
applicable. In addition a cabled recording system would be deployed
from the appropriate vessel in order to capture close range data
suitable for determining a source level estimate. The distances and
directions of any of these sound monitoring locations from the activity
may be changed if, in the opinion of either Port Dolphin or the marine
construction contractors, activities at the planned monitoring
locations could pose health and safety risks or impede vessels or
construction. If the locations must be changed, the
[[Page 55670]]
monitoring would occur at the safest location that is closest to the
proposed location that would not interfere with vessels or
construction. Specific details of monitoring locations for each
activity type are discussed in the next paragraph.
For dredging, Port Dolphin is planning to monitor the operation at
either the exit or entry pit dredges of the western Gulfstream HDD. The
proposed HDD locations are drilling from land to water at the Port
Manatee shore approach and from water-to-water at two crossings of the
Gulfstream pipeline. Port Dolphin is planning to monitor the HDD
operations at the entry pit of the western Gulfstream HDD. For the
pipeline laying, plowing and backfilling the pipeline trench, Port
Dolphin plans to conduct the sound level verification in the Sarasota
Bay Estuarine System. During these activities, the construction spread
would be moving relative to the acoustic monitoring stations. This
would provide a more detailed record of data on received sounds levels
as a function of range and direction from the construction spread.
The commissioning of a new SRV type (i.e., different cargo
containment capacity) at the port may involve the unloading of more
than one shipment of LNG through the port. The sound level verification
program is planned to be implemented only once for each new SRV type
during the approach, unloading, and departure during the first
commissioning shipment. Once the SRV completes its approach to Port
Dolphin and is within approximately 5.6 km of the Port, bow and stern
thrusters would be utilized. Thruster use would vary, operating for 10
to 30 minutes to allow for the proper positioning of the vessel and
allow for connection to the STL buoy. Docking or berthing is expected
to occur at alternate STL buoys approximately every 8 days. The
monitoring program would consist of a similar combination of autonomous
and cabled acoustic recorders as outlined here.
For SRV maneuvering (i.e., approach, docking, unloading, undocking
and departure) operations, Port Dolphin would establish four sound
level measuring stations. As part of the DWPL issued by the MarAd, a
safety zone, an area to be avoided (ATBA), and a no-anchoring zone have
been established around the deepwater port. The boundary of the safety
zone has been set at a distance of 850 m (2,790 ft) from both the
northern and southern STL buoys. The boundaries of both the ATBA and
no-anchoring zone have been set at 1,500 m (4,925 ft) from both the
northern and southern STL buoy.
For the SRV maneuvering to docking/undocking at and departure from
the two STL buoys, the sound level verification measurements would be
taken at the boundary of the ATBA. Three bottom-deployed autonomous
recording stations would therefore be set at a distance of 1,500 m from
the STL buoys. This would ensure that sufficient data is collected
regardless of the SRV's specific approach to the STL buoy. In addition,
a fourth autonomous system would be deployed on a platform directly
below the STL buoy. The recording system used here would have a
frequency response of 1 dB from 10 Hz to 20,000 Hz over the
anticipated measurement range of 100 dB to 220 dB (linear peak re: 1
[mu]Pa) due to the lower frequencies expected.
Visual Monitoring
Visual monitoring of relevant zones would be conducted as described
previously (see `Proposed Mitigation'). Shutdown or delay of activities
would occur as appropriate. The monitoring biologists would document
all marine mammals observed in the monitoring area. Data collection
would include a count of all marine mammals observed by species, sex,
age class, their location within the zone, and their reaction (if any)
to construction activities, including direction of movement, and type
of construction that is occurring, time that activity begins and ends,
any acoustic or visual disturbance, and time of the observation.
Environmental conditions such as wind speed, wind direction,
visibility, and temperature would also be recorded. No monitoring would
be conducted during inclement weather that creates potentially
hazardous conditions, as determined by the PSO(s). No monitoring would
be conducted when visibility is significantly limited, such as during
heavy rain or fog. During these times of inclement weather, in-water
work that may produce sound levels in excess of 180 dB rms may
continue, but may not be started. Impact pile driving shall not occur
when visibility is significantly limited.
All monitoring personnel must have appropriate qualifications as
identified previously. These qualifications include education and
experience identifying marine mammals and the ability to understand and
document marine mammal behavior. All monitoring personnel would meet at
least once for a training session provided by Port Dolphin, and Port
Dolphin would be responsible for verifying to NMFS that PSOs meet the
minimal qualifications described previously. Topics would include, at
minimum, implementation of the monitoring protocol, identification of
marine mammals, and reporting requirements. All monitoring personnel
would be provided a copy of the LOA. Monitoring personnel must read and
understand the contents of the LOA as they relate to coordination,
communication, and identifying and reporting incidental harassment of
marine mammals. All sightings must be recorded on approved marine
mammal field sighting logs.
Proposed Reporting
Reports of data collected during monitoring would be submitted to
NMFS weekly. In addition, a final report summarizing all marine mammal
monitoring and construction activities would be submitted to NMFS
annually. The report would include:
All data described previously under monitoring, including
observation dates, times, and conditions; and
Correlations of observed behavior with activity type and
received levels of sound, to the extent possible.
Port Dolphin would also submit a report(s), as necessary,
concerning the results of all acoustic monitoring. The final report for
acoustic monitoring of construction activities would be provided at the
completion of all marine construction activities. Reporting for
acoustic monitoring of operational activities would be provided at the
completion of the commissioning period for each new SRV servicing the
port. Port Dolphin would to submit these reports to NMFS within 60
working days of the completion of each monitoring event.
Acoustic monitoring reports would include:
A detailed description of the monitoring protocol;
A description of the sound monitoring equipment;
Documentation of calibration activities;
The depth of water at the hydrophone locations and the
depth of the hydrophones;
The background SPL reported as the 50 percent cumulative
density function;
A summary of the data recorded during monitoring; and
Analysis of the recorded data and conclusions.
Analysis of the data should include the frequency spectrum, ranges
and means including the standard deviation/error for the peak and rms
SPLs, and an estimation of the distance at which rms values reach the
relevant marine mammal thresholds and background sound levels.
Vibratory driving results
[[Page 55671]]
would include the maximum and overall average rms calculated from 30-s
rms values during driving of the pile. In addition, for pile driving,
the report would include:
Size and type of any piles driven, correlated with SPLs;
A detailed description of any sound attenuation device
used, including design specifications;
The impact hammer energy rating used to drive the piles,
make and model of the hammer(s), and description of the vibratory
hammer;
The physical characteristics of the bottom substrate into
which the piles were driven; and
The total number of strikes to drive each pile.
During all phases of construction activities and operation,
sightings of any injured or dead marine mammals will be reported
immediately (except as described later in this section) to the NMFS
Southeast Region Marine Mammal Stranding Network, regardless of whether
the injury or death is caused by project activities. In addition, if a
marine mammal is struck by a project vessel (e.g., SRV, support
vessel), or in the unanticipated event that project activity clearly
resulted in the injury, serious injury, or death (e.g., gear
interaction, and/or entanglement) of a marine mammal, USCG and NMFS
must be notified immediately, and a full report must be provided to
NMFS, Southeast Regional Office, and NMFS, Office of Protected
Resources. The report must include the following information: (1) The
time, date, and location (latitude/longitude) of the incident; (2) the
name and type of vessel involved, if applicable; (3) the vessel's speed
during and leading up to the incident, if applicable; (4) a description
of the incident; (5) water depth; (6) environmental conditions (e.g.,
wind speed and direction, sea state, cloud cover, visibility); (7) the
species identification or description of the animal(s) involved; (8)
the fate of the animal(s); and (9) photographs or video footage of the
animal (if equipment is available). Following such an incident,
activities must cease until NMFS is able to review the circumstances of
the incident. NMFS would work with Port Dolphin to determine what is
necessary to minimize the likelihood of further prohibited take and
ensure MMPA compliance. Port Dolphin may not resume activity until
notified to do so by NMFS. If a prohibited take should occur, the NMFS
Office of Law Enforcement and the Florida Fish and Wildlife
Conservation Commission law enforcement would be notified.
In the event that an injured or dead marine mammal is discovered,
and the lead PSO determines that the cause of the injury or death is
unknown and the death is relatively recent (i.e., in less than a
moderate state of decomposition as described in the next paragraph),
Port Dolphin will immediately report the incident to NMFS, Office of
Protected Resources. The report must include the same information
identified in the preceding paragraph. However, activity may continue
while NMFS reviews the circumstances of the incident, and NMFS will
work with Port Dolphin to determine whether modifications to the
activities are appropriate. If the lead PSO determines that the
discovered animal is not associated with or related to project
activities (e.g., previously wounded animal, carcass with moderate to
advanced decomposition, scavenger damage), Port Dolphin would report
the incident to NMFS, Office of Protected Resources, within 24 hours of
the discovery. Port Dolphin should provide photographs or video footage
(if available) or other documentation of the sighting. Activities may
continue while NMFS reviews the circumstances of the incident.
An annual report on marine mammal monitoring and mitigation would
be submitted to NMFS, Office of Protected Resources, and NMFS,
Southeast Regional Office, each year. The weekly and annual reports
would include data collected for each distinct marine mammal species
observed in the project area. Description of marine mammal behavior,
overall numbers of individuals observed, frequency of observation, and
any behavioral changes and the context of the changes relative to
activities would also be included in the annual reports. Additional
information that would be recorded during activities and contained in
the reports include: date and time of marine mammal detections, weather
conditions, species identification, approximate distance from the
source, and activity at the construction site when a marine mammal is
sighted.
In addition to annual reports, Port Dolphin would submit a draft
comprehensive final report to NMFS, Office of Protected Resources, and
NMFS, Southeast Regional Office, 180 days prior to the expiration of
the regulations. This comprehensive technical report would provide full
documentation of methods, results, and interpretation of all monitoring
during the first 4.5 years of the regulations. A revised final
comprehensive technical report, including all monitoring results during
the entire period of the regulations would be due 90 days after the end
of the period of effectiveness of the regulations.
Adaptive Management
The final regulations governing the take of marine mammals
incidental to the specified activities at Port Dolphin would contain an
adaptive management component. In accordance with 50 CFR 216.105(c),
regulations for the proposed activity must be based on the best
available information. As new information is developed, through
monitoring, reporting, or research, the regulations may be modified, in
whole or in part, after notice and opportunity for public review. The
use of adaptive management would allow NMFS to consider new information
from different sources to determine if mitigation or monitoring
measures should be modified (including additions or deletions) if new
data suggest that such modifications are appropriate for subsequent
LOAs.
The following are some of the possible sources of applicable data:
Results from Port Dolphin's monitoring from the previous
year;
Results from general marine mammal and acoustics research;
or
Any information which reveals that marine mammals may have
been taken in a manner, extent or number not authorized by these
regulations or subsequent LOAs.
If, during the effective dates of the regulations, new information
is presented from monitoring, reporting, or research, these regulations
may be modified, in whole, or in part after notice and opportunity of
public review, as allowed for in 50 CFR 216.105(c). In addition, LOAs
would be withdrawn or suspended if, after notice and opportunity for
public comment, the Assistant Administrator finds, among other things,
that the regulations are not being substantially complied with or that
the taking allowed is having more than a negligible impact on the
species or stock, as allowed for in 50 CFR 216.106(e). That is, should
substantial changes in marine mammal populations in the project area
occur or monitoring and reporting show that Port Dolphin actions are
having more than a negligible impact on marine mammals, then NMFS
reserves the right to modify the regulations and/or withdraw or suspend
LOAs after public review.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as: ``any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine
[[Page 55672]]
mammal or marine mammal stock in the wild [Level A harassment]; or (ii)
has the potential to disturb a marine mammal or marine mammal stock in
the wild by causing disruption of behavioral patterns, including, but
not limited to, migration, breathing, nursing, breeding, feeding, or
sheltering [Level B harassment].'' Take by Level B harassment only is
anticipated as a result of Port Dolphin's proposed activities. Take of
marine mammals is anticipated to occur as a result of elevated levels
of sound from the previously described activities associated with
construction and installation of the port and from port operations. No
take by injury, serious injury, or death is anticipated.
As described previously in the ``Distance to Sound Thresholds''
section of this document, JASCO Research modeled a series of scenarios
that thoroughly characterize the various construction/installation and
operation activities expected. JASCO used proxy sound sources selected
from a database of underwater sound measurements. The selected proxy
sound sources were input to a sound propagation model with multiple
parameters, including expected water column sound speeds, bathymetry,
and bottom geoacoustic properties, to estimate the radii of sound
impacts (JASCO, 2008, 2010). Note that for some scenarios, 180-dB
threshold values only occur in the immediate vicinity of individual
pieces of equipment that combine to form a construction ``spread,'' or
modeled scenario, with little or no overlap of the sound fields from
neighboring vessels. These scenarios are for transient activities--for
example, pipelaying and burial activities require a spread of vessels
and equipment (e.g., barges, tugs) rather than a single point source of
sound. These modeled scenarios combine the sound output from multiple
vessels/pieces of equipment. The overall radius depends primarily on
the spacing between the vessels, and a single scenario-specific radius
for the 180-dB threshold cannot sensibly be defined. All activity types
considered here would produce sound source levels attenuating to less
than 180 dB within 200 m; thus, 200 m is used as a conservative
estimator for 180-dB area calculations in most cases.
JASCO's modeling reports the radial distance from each modeled
source to received levels in 10 dB increments (i.e., from 120 dB
through 180 dB), and this information is used here to report the
intensity of sound source levels relative to this 200 m radius in
subsequent sections. Please see Appendices C and D in Port Dolphin's
application for a detailed description of this sound source modeling
and Appendix E for a graphical depiction of the sound fields from
various activities. Results of the modeled underwater analysis for Port
Dolphin construction and operation are summarized as follows:
Buoy installation: Installation of the buoys at the Port
would produce continuous, transient (non-pulsed) sound for a relatively
short period of time during summer, with 120-dB isopleths located 3.9
km from each STL buoy location and corresponding ensonification of
approximately 48 km\2\. At 200 m distance, sound produced by buoy
installation would attenuate to less than 150 dB.
Pipelaying: Pipelaying activities would generate
continuous (non-pulsed) sound, and would be transient as the pipelaying
operation moved along the pipeline route. Construction is expected to
occur during summer and fall. Depending on location, the 120[hyphen]dB
isopleth for pipelaying activities would extend either 6.0 (offshore)
or 7.5 km (inshore) from the source, encompassing approximately 113 or
178 km\2\, respectively. At 200 m distance, sound produced by
pipelaying would attenuate to less than 160 dB.
Pipeline burial: Pipeline burial using the plow system
would generate continuous, transient sound during construction similar
to pipelaying and is expected to occur during fall and winter. Pipeline
burial would only be used in those locations with suitable substrate
conditions. Distances to the 120[hyphen]dB isopleth would be 6.7
(offshore) or 8.4 km (inshore) from the source and would encompass
approximately 141 or 222 km\2\. At 200 m distance, sound produced by
pipeline burial would attenuate to less than 160 dB.
Pile driving: Offshore installation of anchors via impact
pile driving is slated to occur during summer. This impulsive sound
source would produce a 160-dB isopleth at 4.5 km from each STL buoy
location, encompassing approximately 64 km\2\. The 180-dB isopleths
would extend to 180 m from the source, encompassing approximately 0.1
km\2\.
HDD: Horizontal directional drilling within Tampa Bay
would produce continuous, non-pulsed sound and is expected to occur
during summer. The 120-dB isopleth would extend 240 m from the drilling
operation, encompassing approximately 0.2 km\2\. Calculations based on
the area of ensonification for HDD indicate that no marine mammals
would be harassed as a result of this activity. Source levels for this
activity are expected to be below the 180-dB threshold; therefore,
consideration of Level A harassment is not relevant.
HDD vibratory driving: Installation of the goal posts at
each HDD location would produce continuous, non-pulsed sound for a
relatively short period of time, exclusively during summer. The 120-dB
isopleth for HDD vibratory driving would extend 12.6 km from the
source, encompassing approximately 499 km\2\. The 180-dB isopleths
would be less than 10 m from the source.
SRV maneuvering: Once an SRV completes its approach to
Port Dolphin and is within approximately 5.6 km of the port, bow and
stern thrusters would be utilized. Thruster use would vary, operating
for 10 to 30 minutes to allow for the proper positioning of the vessel
and connection to the STL buoy. Docking or berthing would occur at
alternate STL buoys approximately every 8 days. The periodic use of the
thrusters would produce continuous, non-pulsed sound that would be
transient as the vessel moves, with the 120-dB isopleth occurring at
3.6 km from the SRV, encompassing approximately 41 km\2\. The 180-dB
isopleths would be less than 10 m from the source.
Regasification: SRVs would regasify LNG cargo while docked
at a STL buoy, producing continuous, non-pulsed sound. Sound levels for
regasification are low, with the 120-dB isopleth at 170 m from the
source, encompassing approximately 0.09 km\2\. Calculations based on
this area of ensonification indicate that no marine mammals would be
harassed as a result of this activity. Source levels for this activity
are below the 180-dB threshold.
Density of marine mammals in the project area was derived from a
U.S. Navy review of available marine mammal survey data for the eastern
Gulf of Mexico which summarized species presence and distribution on a
seasonal basis (USDON, 2003). As described previously, marine mammal
densities are determined on the basis of both seasonality and depth
stratum. While the area of actual construction and operations for Port
Dolphin is entirely contained within the nearshore depth stratum (0 to
37 m), the sound field from certain construction activity, and thus the
area of effect, extends into the mid-shelf depth stratum (37 to 91 m).
This has implications for the species of marine mammals that may
potentially be affected by the activity. Almost all sound produced by
construction activities would occur within the nearshore stratum. The
only activity with a sound field extending to the mid-shelf depth
stratum is offshore pipelaying, which would occur only
[[Page 55673]]
during construction, from approximately late summer 2013 through early
winter 2013-14. The Level B sound field for this activity would be 99.9
percent contained within the nearshore stratum, with 0.1 percent
projected to enter the mid-shelf stratum. Densities for marine mammals
that may be affected by the proposed activities are presented in Table
8.
Table 8--Density Estimates for Marine Mammals in the Nearshore and Mid-Shelf Depth Strata, Eastern GOM
----------------------------------------------------------------------------------------------------------------
Density (Individuals/100 km\2\ (39 mi\2\))
Species ---------------------------------------------------------------
Winter Spring Summer Fall
----------------------------------------------------------------------------------------------------------------
Nearshore depth stratum:
Atlantic spotted dolphin.................... 2.243 10.752 2.524 10.752
Bottlenose dolphin.......................... 10.913 21.986 8.241 26.744
Mid-shelf depth stratum:
Atlantic spotted dolphin.................... 11.630 21.699 17.354 22.916
Bottlenose dolphin.......................... 7.410 2.588 11.707 10.856
Dwarf/pygmy sperm whale..................... 0.000 0.011 0.011 0.000
Rough-toothed dolphin....................... 0.000 0.000 0.000 0.400
----------------------------------------------------------------------------------------------------------------
Source: USDON, 2003.
Incidental take estimates are calculated based on: (1) The number
of marine mammals that occur within each respective depth stratum,
using species- and season-specific density estimates; (2) the
percentage of sound field within each depth stratum, by source (this is
relevant for offshore pipelaying only); (3) the areal extent of Level A
and Level B sound fields, by sound source; and (4) the time or distance
component of the activity. Areas of ensonification, by appropriate
threshold, are presented in Table 6. With regard to the fourth
component (time/distance), there are two types of construction
activities: stationary and transient. Stationary activities would occur
near specific sites (e.g., locations for buoy installation), while
transient activities would occur while traveling along a pre-determined
trackline (i.e., the pipeline route). Incidental take associated with
stationary activities is determined by considering the estimated number
of days of effect. Buoy installation, impact pile driving, and
vibratory pile driving activities are expected to take 6, 32, and 8
days, respectively. The pre-determined pipeline route along which the
pipelaying and burial activities would occur is approximately 72 km
long (37 km offshore, 35 km inshore). For these transient activities,
the overall area of effect (i.e., distance x width of ensonified area)
is used in calculating estimated incidental take.
For stationary activities, season-specific estimated take was
determined by first multiplying the modeled ZOI (i.e., the area
ensonified using the appropriate thresholds) and the appropriate
species-specific seasonal densities within each depth stratum (USDON,
2003). These results were then rounded to the nearest whole number and
multiplied by the estimated number of days of effect to provide an
estimate of take.
For transient activities, season-specific estimated take was
determined by multiplying the overall area of effect for offshore and
inshore portions, respectively, by the appropriate density and, because
some of these activities are expected to occur during multiple seasons,
by the proportion of trackline expected to be completed during a given
season. For offshore pipelaying, approximately 43 percent of effort is
expected to occur during summer and 57 percent occur during fall. The
inshore portion would occur entirely during fall. For offshore pipe
burial, approximately 12 percent of effort is expected to occur during
fall and 88 percent occurring during winter. The inshore portion would
occur entirely during winter.
For offshore pipelaying, the estimated take within each depth
stratum was then integrated into the seasonal, species-specific
calculations. Calculations indicate that, on the basis of the densities
shown in Table 8 and the 0.1 percent of the sound field for pipelaying
that would occur in the mid-shelf depth stratum, no incidental take of
dwarf/pygmy sperm whales (i.e., Kogia spp.) or rough-toothed dolphins
would occur. Similarly, take of spotted and bottlenose dolphins would
occur only in the nearshore depth stratum (i.e., the 0.1 percent of
effect occurring in the mid-shelf depth stratum would not add to the
total take). Dwarf/pygmy sperm whales and rough-toothed dolphins are
not covered by this proposed rule because incidental take is not
anticipated, and no incidental take is proposed to be authorized. The
results of take estimation calculations for bottlenose dolphins and
spotted dolphins for construction activities are shown in Table 9.
Table 9--Estimated Incidental Take, Construction Activities
----------------------------------------------------------------------------------------------------------------
Species
-------------------------------
Activity Season Atlantic
spotted Bottlenose
dolphin dolphin
----------------------------------------------------------------------------------------------------------------
Buoy installation............................ Summer........................... 6 24
Impact pile driving.......................... Summer........................... 64 160
Pipelaying--Offshore......................... Summer........................... 6 20
Fall............................. 34 85
Pipelaying--Inshore.......................... Fall............................. 45 112
Pipeline burial--Offshore.................... Fall............................. 8 20
Winter........................... 12 60
Pipeline burial--Inshore..................... Winter........................... 11 51
[[Page 55674]]
Vibratory pile driving....................... Summer........................... 104 328
-------------------------------
Total, by species........................ ................................. 290 860
----------------------------------------------------------------------------------------------------------------
When the Port reaches operational status, an estimated 46 SRV
visits would occur per year. Visits would be equally distributed across
seasons, with 12 visits expected during winter and summer seasons and
11 visits per season during spring and fall. Each visit includes
arrival and departure of the SRV, so 46 visits would result in 92
episodes that may result in incidental take. The results of take
estimation calculations for operational activities, for a given year,
are shown in Table 10.
Table 10--Estimated Yearly Incidental Take, Port Operations
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin Bottlenose dolphin
---------------------------------------------------------------
Activity Season Trips Single visit Single visit
\1\ Seasonal \1\ Seasonal
--------------------------------------------------------------------------------------------------------------------------------------------------------
SRV maneuvering.......................... Summer....................... 12 2 24 7 84
Fall......................... 11 9 99 22 242
Winter....................... 12 2 24 9 108
Spring....................... 11 9 99 18 198
-------------------------------------------------------------------------------
Totals \2\........................... ............................. 46 .............. 246 .............. 632
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Single-visit take calculated by multiplying appropriate density and appropriate area, then doubling the result to account for arrival and departure
of the SRV in a single trip.
\2\ Total represents the single visit take multiplied by the total number of trips.
Assuming that this proposed rulemaking would be in effect during 1
year of construction and 4 years of operations, the total estimated
taking, by Level B harassment only, would be 1,274 Atlantic spotted
dolphins and 3,388 bottlenose dolphins.
Negligible Impact and Small Numbers Analysis and Preliminary
Determination
NMFS has defined ``negligible impact'' in 50 CFR 216 as ``* * * an
impact resulting from the specified activity that cannot be reasonably
expected to, and is not reasonably likely to, adversely affect the
species or stock through effects on annual rates of recruitment or
survival.'' In making a negligible impact determination, NMFS considers
a variety of factors, including but not limited to: (1) The number of
anticipated mortalities; (2) the number and nature of anticipated
injuries; (3) the number, nature, intensity, and duration of Level B
harassment; and (4) the context in which the takes occur.
Incidental take, in the form of Level B harassment only, is likely
to occur primarily as a result of marine mammal exposure to elevated
levels of sound resulting from the specified activities. No take by
injury, serious injury, or death is anticipated or proposed for
authorization. The expected impacts from this activity would be Level B
harassment in the form of behavioral disturbance resulting in, for
example, changed direction or speed, or temporary avoidance of an area.
Anticipated behavioral disturbance is likely to be of low intensity due
to the sound source characteristics--the majority of activities
considered here would produce low source levels of non-pulsed sound
that would be either intermittent or transient--and relatively short in
duration associated with the specified activities. For the same
reasons, no individual marine mammals are expected to incur any hearing
impairment, whether temporary or permanent in nature. That is, non-
pulsed sound does not produce the rapid rise times that are more likely
to produce hearing impairment in marine mammals, and the low intensity
of the sources would result in Level A isopleths within a short
distance. Several activities would produce source levels below those
considered capable of causing hearing impairment, even in close
proximity to marine mammals. The shutdown zone monitoring proposed as
mitigation, and the small size of the zones in which injury may occur,
further reduces the potential for any injury of marine mammals, making
the possibility of hearing impairment extremely unlikely and therefore
discountable.
For the greater portion of the life of this proposed rule (i.e., 4
years remaining after the first year of construction), only port
operations would occur. Each episode of SRV arrival/departure
(requiring thruster use for a period of several hours) would be
separated by approximately 8 days of regasification, an activity not
expected to result in incidental take. The likely effects of behavioral
disturbance from port operations are minor, as many animals perform
vital functions, such as feeding, resting, traveling, and socializing,
on a diel (24-hour) cycle. Behavioral reactions to sound exposure (such
as disruption of critical life functions, displacement, or avoidance of
important habitat) are more likely to be significant if they last more
than one diel cycle or recur on subsequent days (Southall et al.,
2007). Operational activities would occur on a single day (i.e.,
arrival or departure of a SRV), would not recur for a period of 8 days,
and, as for the majority of construction activities, would produce only
low levels of non-pulsed sound. NMFS' current criterion for Level B
harassment from non-pulsed, underwater sound levels (the vast majority
of sound produced by the proposed activities) is 120 dB rms. However,
not all marine mammals react to sounds at this low level, and many will
not show strong reactions (and in some cases any
[[Page 55675]]
reaction) until sounds are much stronger.
Neither the bottlenose dolphin nor spotted dolphin is listed under
the ESA. However, NMFS considers the bay, sound, and estuarine stock of
bottlenose dolphins (of which the Tampa Bay/Sarasota Bay populations
are a component) to be strategic under the MMPA. NMFS is in the process
of writing individual stock assessment reports for each of the 32 bay,
sound and estuary stocks of bottlenose dolphins, but none has been
completed for the Tampa Bay/Sarasota Bay populations. There is
insufficient data to determine population trends or status of the
relevant stocks relative to optimum sustainable population. Population
estimates for these species were provided earlier in this document (see
the ``Description of Marine Mammals in the Area of the Specified
Activity'' section).
The maximum estimated take per year of Atlantic spotted dolphins
(290) would be small relative to the stock size (37,611; 0.1 percent);
this would decline for subsequent years of operations. As a result,
only small numbers of Atlantic spotted dolphins would be taken. For
bottlenose dolphins, the maximum estimated total take per year for all
bottlenose dolphins (860) is small relative to the coastal stock size
(7,702; 11 percent); this would decline for subsequent years of
operations. As a result, only small numbers of bottlenose dolphins from
the coastal stock could be taken. However, it is difficult to partition
potential takings between the coastal stock (7,702) and the smaller
bay, sound, and estuarine stock (719) because the possibility for
mixing of the stocks precludes any quantitative understanding of how
the total estimated taking might be apportioned between stocks.
Although it is not possible to predict that portion of overall
incidental take that might accrue to bay dolphin populations, NMFS
believes that the potential effects of the proposed activities
represent a negligible impact for bay dolphins. Only a subset of the
specified activities has the potential to affect bay dolphins. Buoy
installation and impact pile driving, as well as the entire offshore
portion of pipelaying and burial, would occur offshore and would not
have the potential to affect the bay dolphin populations. Vibratory
pile driving would occur entirely within Tampa Bay, as would a portion
of inshore pipelaying and burial, and could impact the bay populations.
Vibratory pile driving would occur for only 8 days (at two piles per
day), meaning that any harassment experienced by bay dolphins from this
activity would be of very short duration. In addition, Tampa Bay is
significantly industrialized and urbanized and is heavily used by
recreational boaters. Bottlenose dolphins occurring in Tampa Bay are
somewhat acclimated to disturbance and would not be expected to
experience significant disruption to behavioral patterns on the basis
of short-term and low intensity disturbance, such as is proposed for
this project. The proposed activities would not take place in areas
known to be of special significance for feeding or breeding.
In summary, NMFS believes that potential impacts to bay dolphins
represent a negligible impact for the following reasons: (1) Only a
subset of project activities have the potential to affect bay dolphins;
(2) any takes would be of low intensity (resulting from exposure to low
levels of non-pulsed sound over a limited duration) and likely would
not result in significant alteration of dolphin behavior in the heavily
urbanized/industrialized area where the activity would occur; (3) any
takes are likely to represent repeated takes of individuals using the
area where the activity is occurring, rather than each take being of a
new individual; and (4) an unknown, but possibly large, number of
coastal stock dolphins may be mixing in inshore waters at any given
time, and it is not possible to accurately determine how many of the
takes may occur to individuals of the coastal stock versus individuals
of the bay stock. Finally, following the initial year of construction,
all operations would occur offshore, and there would be no potential
for incidental take of bay dolphins.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the mitigation and monitoring
measures, NMFS preliminarily finds that construction and operation of
Port Dolphin would result in the incidental take of small numbers of
marine mammals, by Level B harassment only, and that the total taking
from Port Dolphin's proposed activities would have a negligible impact
on the affected species or stocks.
Impact on Availability of Affected Species or Stock for Taking for
Subsistence Uses
There are no relevant subsistence uses of marine mammals implicated
by this action.
Endangered Species Act (ESA)
On August 4, 2009, NMFS concluded consultation with MarAd and USCG
under section 7 of the ESA on the proposed construction and operation
of the Port Dolphin LNG facility. The result of that consultation was
NMFS' concurrence with Port Dolphin's determination that the proposed
activities may affect, but are not likely to adversely affect, listed
species under NMFS' jurisdiction. NMFS does not propose to authorize
incidental take of any ESA-listed marine mammal species. No listed
species will be impacted by the specified activities.
National Environmental Policy Act (NEPA)
The USCG and the MarAd initiated the public scoping process in July
2007, with the publication of a Notice of Intent (NOI) to prepare an
Environmental Impact Statement (EIS) in the Federal Register. The NOI
included information on public meetings and informational open houses;
requested public comments on the scope of the EIS; and provided
information on how the public could submit comments. A Notice of
Availability for the Draft EIS was published in the Federal Register in
April 2008. Subsequently, a final EIS was published in July 2009. MarAd
issued a Record of Decision (ROD) approving, with conditions, the Port
Dolphin Energy Deepwater Port License application on October 26, 2009.
Because NMFS was a cooperating agency in the development of the
Port Dolphin EIS, NMFS will adopt the EIS and, if appropriate, issue
its own ROD for issuance of authorizations pursuant to section
101(a)(5)(A) of the MMPA for the activities proposed by Port Dolphin.
Information Solicited
NMFS requests interested persons to submit comments, information,
and suggestions concerning the request and the content of the proposed
regulations to authorize the taking (see ADDRESSES).
Classification
The Office of Management and Budget (OMB) has determined that this
proposed rule is not significant for purposes of Executive Order 12866.
Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA),
the Chief Counsel for Regulation of the Department of Commerce has
certified to the Chief Counsel for Advocacy of the Small Business
Administration that this proposed rule, if adopted, would not have a
significant economic impact on a substantial number of small entities.
Port Dolphin Energy LLC is the only
[[Page 55676]]
entity that would be subject to the requirements in these proposed
regulations. Port Dolphin is ultimately owned by the Norway-based
shipping company H[ouml]egh LNG AS, which is itself held by Leif
H[ouml]egh & Co, a global shipping company. Therefore, it is not a
small governmental jurisdiction, small organization, or small business,
as defined by the RFA. Because of this certification, a regulatory
flexibility analysis is not required, and none has been prepared.
Notwithstanding any other provision of law, no person is required
to respond to nor shall a person be subject to a penalty for failure to
comply with a collection of information subject to the requirements of
the Paperwork Reduction Act (PRA) unless that collection of information
displays a currently valid OMB control number. This proposed rule
contains collection-of-information requirements subject to the
provisions of the PRA. These requirements have been approved by OMB
under control number 0648-0151 and include applications for
regulations, subsequent LOAs, and reports. Send comments regarding any
aspect of this data collection, including suggestions for reducing the
burden, to NMFS and the OMB Desk Officer (see ADDRESSES).
List of Subjects in 50 CFR Part 217
Exports, Fish, Imports, Indians, Labeling, Marine mammals,
Penalties, Reporting and recordkeeping requirements, Seafood,
Transportation.
Dated: September 4, 2012.
Alan D. Risenhoover,
Director, Office of Sustainable Fisheries, performing the functions and
duties of the Deputy Assistant Administrator for Regulatory Programs,
National Marine Fisheries Service.
For reasons set forth in the preamble, 50 CFR part 217 is proposed
to be amended as follows:
PART 217--REGULATIONS GOVERNING THE TAKE OF MARINE MAMMALS
INCIDENTAL TO SPECIFIED ACTIVITIES
1. The authority citation for part 217 continues to read as
follows:
Authority: 16 U.S.C. 1361 et seq.
2. Subpart P is added to part 217 to read as follows:
Subpart P--Taking Marine Mammals Incidental to Construction and
Operation of a Liquefied Natural Gas Deepwater Port in the Gulf of
Mexico
Sec.
217.151 Specified activity and specified geographical region.
217.152 Effective dates.
217.153 Permissible methods of taking.
217.154 Prohibitions.
217.155 Mitigation.
217.156 Requirements for monitoring and reporting.
217.157 Letters of Authorization.
217.158 Renewals and Modifications of Letters of Authorization.
Subpart P--Taking Marine Mammals Incidental to Construction and
Operation of a Liquefied Natural Gas Deepwater Port in the Gulf of
Mexico
Sec. 217.151 Specified activity and specified geographical region.
(a) Regulations in this subpart apply only to Port Dolphin Energy
LLC (Port Dolphin) and those persons it authorizes to conduct
activities on its behalf for the taking of marine mammals that occurs
in the area outlined in paragraph (b) of this section and that occur
incidental to construction and operation of the Port Dolphin Deepwater
Port (Port).
(b) The taking of marine mammals by Port Dolphin may be authorized
in a Letter of Authorization (LOA) only if it occurs in the vicinity of
the Port Dolphin Deepwater Port in the eastern Gulf of Mexico or along
the associated pipeline route.
Sec. 217.152 Effective dates.
[Reserved]
Sec. 217.153 Permissible methods of taking.
(a) Under LOAs issued pursuant to Sec. 216.106 and Sec. 217.157
of this chapter, the Holder of the LOA (hereinafter ``Port Dolphin'')
may incidentally, but not intentionally, take marine mammals within the
area described in Sec. 217.151(b) of this chapter, provided the
activity is in compliance with all terms, conditions, and requirements
of the regulations in this subpart and the appropriate LOA.
(b) The incidental take of marine mammals under the activities
identified in Sec. 217.151(a) of this chapter is limited to the
following species and is limited to Level B Harassment:
(1) Bottlenose dolphin (Tursiops truncatus)--3,388 (860 the first
year and an average of 632 annually thereafter)
(2) Atlantic spotted dolphin (Stenella frontalis)--1,274 (290 the
first year and an average of 246 annually thereafter)
Sec. 217.154 Prohibitions.
Notwithstanding takings contemplated in Sec. 217.151 of this
chapter and authorized by a LOA issued under Sec. 216.106 and Sec.
217.157 of this chapter, no person in connection with the activities
described in Sec. 217.151 of this chapter may:
(a) Take any marine mammal not specified in Sec. 217.153(b) of
this chapter;
(b) Take any marine mammal specified in Sec. 217.153(b) of this
chapter other than by incidental, unintentional Level B Harassment;
(c) Take a marine mammal specified in Sec. 217.153(b) of this
chapter if such taking results in more than a negligible impact on the
species or stocks of such marine mammal; or
(d) Violate, or fail to comply with, the terms, conditions, and
requirements of this subpart or a LOA issued under Sec. 216.106 and
Sec. 217.157 of this chapter.
Sec. 217.155 Mitigation.
(a) When conducting the activities identified in Sec. 217.151(a)
of this chapter, the mitigation measures contained in any LOA issued
under Sec. 216.106 and Sec. 217.157 of this chapter must be
implemented. These mitigation measures include but are not limited to:
(1) General Conditions:
(i) Briefings shall be conducted between the Port Dolphin project
construction supervisors and the crew, protected species observer(s)
(PSO), and acoustic monitoring team prior to the start of all
construction activity, and when new personnel join the work, to explain
responsibilities, communication procedures, protected species
monitoring protocol, and operational procedures.
(ii) Port Dolphin shall comply with all applicable equipment sound
standards and ensure that all construction equipment has sound control
devices no less effective than those provided on the original
equipment. Vessel crew and contractors shall minimize the production of
underwater sound to the extent possible. Equipment and/or procedures
used may include the use of enclosures and mufflers on equipment,
minimizing the use of thrusters, and turning off engines and equipment
when not in use.
(iii) All vessels associated with Port Dolphin construction and
operations shall comply with NMFS Vessel Strike Avoidance Measures and
Reporting for Mariners and applicable regulations. All vessels
associated with Port Dolphin construction and operations shall remain
500 yd (457 m) away from North Atlantic right whales (Eubalaena
glacialis) and 100 yd (91 m) away from all other marine mammals, except
in cases where small marine mammals (i.e., delphinids) voluntarily
approach within 100 yd or unless constrained by human safety concerns
or navigational constraints.
(2) Shutdown and Monitoring:
(i) Shutdown zone: For all activities, shutdown zones shall be
established. These zones shall include all areas where underwater sound
pressure levels
[[Page 55677]]
(SPLs) are anticipated to equal or exceed 180 dB re: 1 [mu]Pa rms, as
determined by modeled scenarios approved by NMFS for each specific
activity. The actual size of these zones shall be empirically
determined and reported by Port Dolphin. For all non-stationary
activities (e.g., pipeline burial, shuttle regasification vessel (SRV)
maneuvering), Port Dolphin shall maintain a minimum 100 yd (91 m)
distance from marine mammals, with the exception that voluntary
approach (e.g., bow riding) within the 100 yd zone by delphinids shall
not trigger shutdown requirements.
(ii) Disturbance zone: For all activities, disturbance zones shall
be established. For impact pile driving, these zones shall include all
areas where underwater SPLs are anticipated to equal or exceed 160 dB
re: 1 [mu]Pa rms. For all other activities these zones shall include
all areas where underwater SPLs are anticipated to equal or exceed 120
dB re: 1 [mu]Pa rms. These zones shall be established on the basis of
modeled scenarios approved by NMFS for each specific activity. The
actual size of disturbance zones shall be empirically determined and
reported by Port Dolphin, and on-site PSOs shall be aware of the size
of these zones. However, because of the large size of these zones,
monitoring of the zone is required only to maximum line-of-sight
distance from established monitoring locations.
(iii) Monitoring of shutdown and disturbance zones shall occur for
all activities. The following measures shall apply:
(A) Shutdown and disturbance zones shall be monitored from the
appropriate vessel or work platform, or other suitable vantage point.
Port Dolphin shall at all times employ, at minimum, two PSOs in
association with each concurrent specified construction activity.
(B) The shutdown zone shall be monitored for the presence of marine
mammals before, during, and after construction activity. For all
activities, the shutdown zone shall be monitored for 30 minutes prior
to initiating the start of activity and for 30 minutes following the
completion of activity. If marine mammals are present within the
shutdown zone prior to initiating activity, the start shall be delayed
until the animals leave the shutdown zone of their own volition or
until 15 minutes has elapsed without observing the animal. If a marine
mammal is observed within or approaching the shutdown zone, activity
shall be halted as soon as it is safe to do so, until the animal is
observed exiting the shutdown zone or 15 minutes has elapsed. If a
marine mammal is observed within the disturbance zone, a take shall be
recorded and behaviors documented.
(C) PSOs shall be on watch at all times during daylight hours when
in[hyphen]water operations are being conducted, unless conditions
(e.g., fog, rain, darkness) make observations impossible. If conditions
deteriorate during daylight hours such that the sea surface
observations are halted, visual observations must resume as soon as
conditions permit. While activities will be permitted to continue
during low-visibility conditions, they (1) must have been initiated
following proper clearance of the shutdown zone under acceptable
observation conditions; and (2) must be restarted, if halted for any
reason, using the appropriate shutdown zone clearance procedures as
described in Sec. 217.155(a)(2)(iii)(B) of this chapter.
(3) Pile driving:
(i) A minimum shutdown zone of 250 m radius shall be established
around all impact pile driving activity.
(ii) Contractors shall reduce the power of impact hammers to
minimum energy levels required to drive a pile.
(iii) Port Dolphin shall use a sound attenuation measure for impact
driving of pilings. Prior to beginning construction, Port Dolphin must
provide information to NMFS about the device to be used, including
technical specifications. NMFS must approve use of the device before
construction may begin. If a bubble curtain or similar measure is used,
it shall distribute small air bubbles around 100 percent of the piling
perimeter for the full depth of the water column. Any other attenuation
measure (e.g., temporary sound attenuation pile) must provide 100
percent coverage in the water column for the full depth of the pile.
Prior to any impact pile driving, a performance test of the sound
attenuation device must be conducted in accordance with a NMFS-approved
acoustic monitoring plan. If a bubble curtain or similar measure is
utilized, the performance test shall confirm the calculated pressures
and flow rates at each manifold ring.
(iv) Ramp-up:
(A) A ramp-up technique shall be used at the beginning of each
day's in-water pile driving activities and if pile driving resumes
after it has ceased for more than 1 hour.
(B) If a vibratory driver is used, contractors shall be required to
initiate sound from vibratory hammers for 15 seconds at reduced energy
followed by a 1-minute waiting period. The procedure shall be repeated
two additional times before full energy may be achieved.
(C) If a non-diesel impact hammer is used, contractors shall be
required to provide an initial set of strikes from the impact hammer at
reduced energy, followed by a 1-minute waiting period, then two
subsequent sets.
(D) If a diesel impact hammer is used, contractors shall be
required to turn on the sound attenuation device for 15 seconds prior
to initiating pile driving.
(v) No impact pile driving shall occur when visibility in the
shutdown zone is significantly limited, such as during heavy rain or
fog.
(4) Additional mitigation measures:
(i) Use of lights during construction activities shall be limited
to areas where work is actually occurring, and all other lights must be
extinguished. Lights must be shielded such that they illuminate the
deck and do not intentionally illuminate surrounding waters, to the
extent possible.
(ii) Additional mitigation measures as contained in a LOA issued
under Sec. 216.106 and Sec. 217.157 of this chapter.
(b) [Reserved]
Sec. 217.156 Requirements for monitoring and reporting.
(a) Visual monitoring program:
(1) Port Dolphin shall employ, at minimum, two qualified PSOs
during specified construction-related activities at each site where
such activities are occurring. All PSOs must be selected in conformance
with NMFS' minimum qualifications, as described in the preamble to this
rule, and must receive training sponsored by Port Dolphin, with topics
to include, at minimum, implementation of the monitoring protocol,
identification of marine mammals, and reporting requirements. The PSOs
shall be responsible for visually locating marine mammals in the
shutdown and disturbance zones and, to the extent possible, identifying
the species. PSOs shall record, at minimum, the following information:
(i) A count of all marine mammals observed by species, sex, and age
class, when possible.
(ii) Their location within the shutdown or disturbance zone, and
their reaction (if any) to construction activities, including direction
of movement.
(iii) Activity that is occurring at the time of observation,
including time that activity begins and ends, any acoustic or visual
disturbance, and time of the observation.
(iv) Environmental conditions, including wind speed, wind
direction, visibility, and temperature.
(2) Port Dolphin shall sponsor a training course to designated crew
members assigned to vessels associated
[[Page 55678]]
with construction activities or support of operations who will have
responsibilities for watching for marine mammals. This course shall
cover topics including, but not limited to, descriptions of the marine
mammals found in the area, mitigation and monitoring requirements
contained in a LOA, sighting log requirements, provisions of NMFS
Vessel Strike Avoidance Measures and Reporting for Mariners, and
procedures for reporting injured or dead marine mammals.
(3) Monitoring shall be conducted using appropriate binoculars,
such as 8x50 marine binoculars. When possible, digital video or still
cameras shall also be used to document the behavior and response of
marine mammals to construction activities or other disturbances.
(4) Each PSO shall have two-way communication capability for
contact with other PSOs or work crews. PSOs shall implement shut-down
or delay procedures when applicable by calling for the shut-down to the
equipment/vessel operator.
(5) A GPS unit and/or appropriate range finding device shall be
used for determining the observation location and distance to marine
mammals, vessels, and construction equipment.
(6) During arrival and departure of SRVs and regasification,
qualified PSOs may not be required. During SRV arrival and departure,
while thrusters are engaged for maneuvering, an additional lookout
shall be designated to exclusively and continuously monitor for marine
mammals. All sightings of marine mammals by the designated lookout,
individuals posted to navigational lookout duties, or any other crew
member while the SRV is maneuvering or in transit to or from the Port
shall be immediately reported to the watch officer who shall then alert
the Master. The SRV must report to Port Dolphin any observations of
marine mammals while maneuvering with thrusters.
(b) Acoustic monitoring program:
(1) Port Dolphin must provide NMFS with an acoustic monitoring plan
describing the planned measurement of underwater sound pressure levels
from designated construction and operation activities as well as the
characterization of site-specific sound propagation. NMFS must approve
this plan before activities may begin, and acoustic monitoring must be
conducted in accordance with the plan.
(2) Port Dolphin shall provide NMFS with empirically measured
source level data for designated sources of sound associated with Port
construction and operation activities and shall verify distances to
relevant sound thresholds. Measurements shall be carefully coordinated
with sound-producing activities.
(3) [Reserved]
(c) Reporting--Port Dolphin must implement the following reporting
requirements:
(1) A report of data collected during monitoring shall be submitted
to NMFS following conclusion of construction activities. Subsequent
reports concerning Port operations shall be submitted annually. The
reports shall include:
(i) All data required to be collected during monitoring, as
described under 217.156(a) of this chapter, including observation
dates, times, and conditions;
(ii) Correlations of observed behavior with activity type and
received levels of sound, to the extent possible; and
(iii) Estimations of total incidental take of marine mammals,
extrapolated from observed incidental take.
(2) Port Dolphin shall also submit a report(s) concerning the
results of all acoustic monitoring. Acoustic monitoring reports shall
include information as described in a NMFS-approved acoustic monitoring
plan.
(3) Reporting injured or dead marine mammals:
(i) In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by a LOA (if
issued), such as an injury (Level A harassment), serious injury, or
mortality, Port Dolphin shall immediately cease the specified
activities and report the incident to the Chief of the Permits and
Conservation Division, Office of Protected Resources, NMFS, and the
Southeast Regional Stranding Coordinator, NMFS. The report must include
the following information:
(A) Time and date of the incident;
(B) Description of the incident;
(C) Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
(D) Description of all marine mammal observations in the 24 hours
preceding the incident;
(E) Species identification or description of the animal(s)
involved;
(F) Fate of the animal(s); and
(G) Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with Port Dolphin
to determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. Port Dolphin may
not resume their activities until notified by NMFS.
(ii) In the event that Port Dolphin discovers an injured or dead
marine mammal, and the lead PSO determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), Port Dolphin shall immediately
report the incident to the Chief of the Permits and Conservation
Division, Office of Protected Resources, NMFS, and the Southeast
Regional Stranding Coordinator, NMFS. The report must include the same
information identified in 217.156(b)(3)(i) of this chapter. Activities
may continue while NMFS reviews the circumstances of the incident. NMFS
will work with Port Dolphin to determine whether additional mitigation
measures or modifications to the activities are appropriate.
(iii) In the event that Port Dolphin discovers an injured or dead
marine mammal, and the lead PSO determines that the injury or death is
not associated with or related to the activities authorized in the LOA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), Port Dolphin shall report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources, NMFS, and the Southeast Regional Stranding
Coordinator, NMFS, within 24 hours of the discovery. Port Dolphin shall
provide photographs or video footage or other documentation of the
stranded animal sighting to NMFS.
(4) Annual Reports.
(i) A report summarizing all marine mammal monitoring and
construction activities shall be submitted to NMFS, Office of Protected
Resources, and NMFS, Southeast Regional Office (specific contact
information to be provided in LOA) following the conclusion of
construction activities. Thereafter, Port Dolphin shall submit annual
reports summarizing marine mammal monitoring and operations activities.
(ii) The annual reports shall include data collected for each
distinct marine mammal species observed in the project area.
Description of marine mammal behavior, overall numbers of individuals
observed, frequency of observation, and any behavioral changes and the
context of the changes relative to activities shall also be included in
the reports. Additional information that shall be recorded during
activities and contained in the reports include: Date and time of
marine mammal detections, weather conditions, species
[[Page 55679]]
identification, approximate distance from the source, and activity at
the construction site when a marine mammal is sighted.
(5) Five-year Comprehensive Report.
(i) Port Dolphin shall submit a draft comprehensive final report to
NMFS, Office of Protected Resources, and NMFS, Southeast Regional
Office (specific contact information to be provided in LOA) 180 days
prior to the expiration of the regulations. This comprehensive
technical report shall provide full documentation of methods, results,
and interpretation of all monitoring during the first 4.5 years of the
activities conducted under the regulations in this Subpart.
(ii) Port Dolphin shall submit a revised final comprehensive
technical report, including all monitoring results during the entire
period of the LOAs, 90 days after the end of the period of
effectiveness of the regulations to NMFS, Office of Protected
Resources, and NMFS, Southeast Regional Office (specific contact
information to be provided in LOA).
Sec. 217.157 Letters of Authorization.
(a) To incidentally take marine mammals pursuant to these
regulations, Port Dolphin must apply for and obtain a LOA.
(b) A LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the expiration date of these regulations.
(c) If an LOA expires prior to the expiration date of these
regulations, Port Dolphin must apply for and obtain a renewal of the
LOA.
(d) In the event of projected changes to the activity or to
mitigation and monitoring measures required by an LOA, Port Dolphin
must apply for and obtain a modification of the LOA as described in
Sec. 217.158 of this chapter.
(e) The LOA shall set forth:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, its habitat, and on the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
(f) Issuance of the LOA shall be based on a determination that the
level of taking will be consistent with the findings made for the total
taking allowable under these regulations.
(g) Notice of issuance or denial of a LOA shall be published in the
Federal Register within 30 days of a determination.
Sec. 217.158 Renewals and modifications of Letters of Authorization.
(a) A LOA issued under Sec. 216.106 and Sec. 217.157 of this
chapter for the activity identified in Sec. 217.151(a) of this chapter
shall be renewed or modified upon request by the applicant, provided
that: (1) The proposed specified activity and mitigation, monitoring,
and reporting measures, as well as the anticipated impacts, are the
same as those described and analyzed for these regulations (excluding
changes made pursuant to the adaptive management provision in Sec.
217.158(c)(1) of this chapter), and (2) NMFS determines that the
mitigation, monitoring, and reporting measures required by the previous
LOA under these regulations were implemented.
(b) For LOA modification or renewal requests by the applicant that
include changes to the activity or the mitigation, monitoring, or
reporting (excluding changes made pursuant to the adaptive management
provision in Sec. 217.158(c)(1) of this chapter) that do not change
the findings made for the regulations or result in no more than a minor
change in the total estimated number of takes (or distribution by
species or years), NMFS may publish a notice of proposed LOA in the
Federal Register, including the associated analysis of the change, and
solicit public comment before issuing the LOA.
(c) A LOA issued under Sec. 216.106 and Sec. 217.157 of this
chapter for the activity identified in Sec. 217.151(a) of this chapter
may be modified by NMFS under the following circumstances:
(1) Adaptive Management--NMFS may modify (including augment) the
existing mitigation, monitoring, or reporting measures (after
consulting with Port Dolphin regarding the practicability of the
modifications) if doing so creates a reasonable likelihood of more
effectively accomplishing the goals of the mitigation and monitoring
set forth in the preamble for these regulations.
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in an LOA:
(A) Results from Port Dolphin's monitoring from the previous
year(s).
(B) Results from other marine mammal and/or sound research or
studies.
(C) Any information that reveals marine mammals may have been taken
in a manner, extent or number not authorized by these regulations or
subsequent LOAs.
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
will publish a notice of proposed LOA in the Federal Register and
solicit public comment.
(2) Emergencies--If NMFS determines that an emergency exists that
poses a significant risk to the well-being of the species or stocks of
marine mammals specified in Sec. 217.153(b) of this chapter, an LOA
may be modified without prior notice or opportunity for public comment.
Notice would be published in the Federal Register within 30 days of the
action.
[FR Doc. 2012-22092 Filed 9-7-12; 8:45 am]
BILLING CODE 3510-22-P