[Federal Register Volume 80, Number 234 (Monday, December 7, 2015)]
[Notices]
[Pages 75978-75997]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-30745]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XE271
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Bravo Wharf Recapitalization
Project
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for
authorization to take marine mammals incidental to construction
activities as part of a wharf recapitalization project. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting public comment
on its proposal to issue an incidental harassment authorization (IHA)
to the Navy to incidentally take marine mammals, by Level B harassment
only, during the specified activity.
DATES: Comments and information must be received no later than January
6, 2016.
ADDRESSES: Comments on this proposal should be addressed to Jolie
Harrison, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service. Physical comments should
be sent to 1315 East-West Highway, Silver Spring, MD 20910 and
electronic comments should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted to the Internet at
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without
change. All personal identifying information (e.g., name, address)
voluntarily submitted by the commenter may be publicly accessible. Do
not submit confidential business information or otherwise sensitive or
protected information.
FOR FURTHER INFORMATION CONTACT: Laura McCue, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
An electronic copy of the Navy's application and supporting
documents, as well as a list of the references cited in this document,
may be obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing
these documents, please call the contact listed above.
National Environmental Policy Act
The Navy has prepared a draft Environmental Assessment (Wharf Bravo
Recapitalization at Naval Station Mayport, Jacksonville, FL) in
accordance with the National Environmental Policy Act (NEPA) and the
regulations published by the Council on Environmental Quality. It is
posted at the aforementioned site. NMFS will independently evaluate the
EA and determine whether or not to adopt it. We may prepare a separate
NEPA analysis and incorporate relevant portions of Navy's EA by
reference. Information in the Navy's application, EA, and this notice
collectively provide the environmental information related to proposed
issuance of this IHA for public review and comment. We will review all
comments submitted in response to this notice as we complete the NEPA
process, including a decision of whether to sign a Finding of No
Significant Impact (FONSI), prior to a final decision on the incidental
take authorization request.
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 by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified area, the incidental, but not intentional,
taking of small numbers of marine mammals, providing that certain
findings are made and the necessary prescriptions are established.
The incidental taking of small numbers of marine mammals may be
allowed only if NMFS (through authority delegated by the Secretary)
finds that the total taking by the specified activity during the
specified time period will (i) have a negligible impact on the species
or stock(s) and (ii) not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant). Further, the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such taking
must be set forth, either in specific regulations or in an
authorization.
The allowance of such incidental taking under section 101(a)(5)(A),
by harassment, serious injury, death, or a combination thereof,
requires that regulations be established. Subsequently, a Letter of
Authorization may be issued pursuant to the prescriptions established
in such regulations, providing that the level of taking will be
consistent with the findings made for the total taking allowable under
the specific regulations. Under section 101(a)(5)(D), NMFS may
authorize such incidental taking by harassment only, for periods of not
more than one year, pursuant to requirements and conditions contained
within an IHA. The establishment of prescriptions through either
specific regulations or an authorization requires notice and
opportunity for public comment.
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, section 3(18) of 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 July 21, 2015, we received a request from the Navy for
authorization of the taking, by Level B harassment only, of marine
mammals, incidental to pile driving in association with the
[[Page 75979]]
Bravo Wharf recapitalization project at Naval Station Mayport, Florida
(NSM). That request was modified on November 4 and November 10, and a
final version, which we deemed adequate and complete, was submitted on
November 17. In-water work associated with the project is expected to
be completed within the one-year timeframe of the proposed IHA (October
15, 2016 through September 30, 2017).
The use of both vibratory and impact pile driving is expected to
produce underwater sound at levels that have the potential to result in
behavioral harassment of marine mammals. One species of marine mammal
has the potential to be affected by the specified activities:
bottlenose dolphin (Tursiops truncatus truncatus). This species may
occur year-round in the action area.
Similar wharf construction and pile driving activities in Naval
Station Mayport have been authorized by NMFS in the past. The first
authorization was effective between September 1, 2014 through August
31, 2015, and the second authorization, which is currently ongoing, is
effective from September 8, 2015 through September 7, 2016.
Description of the Specified Activity
Overview
Bravo Wharf is a medium draft, general purpose berthing wharf that
was constructed in 1970 and lies at the western edge of the NSM turning
basin. Bravo Wharf is approximately 2,000 ft long, 125 ft wide, and has
a berthing depth of 50 ft mean lower low water. The wharf is one of two
primary deep draft berths at the basin and is capable of berthing ships
up to and including large amphibious ships; it is one of three primary
ordnance handling berths at the basin. The wharf is a diaphragm steel
sheet pile cell structure with a concrete apron, partial concrete
encasement of the piling and asphalt paved deck. The wharf is currently
in poor condition due to advanced deterioration of the steel sheeting
and lack of corrosion protection. This structural deterioration has
resulted in the institution of load restrictions within 60 ft of the
wharf face. The purpose of this project is to complete necessary
repairs to Bravo Wharf. Please refer to the Navy's application for a
schematic of the project plan.
Dates and Duration
The total project is expected to require a maximum of 130 days of
in-water pile driving. The project may require up to 24 months for
completion; in-water activities are limited to a maximum of 130 days,
separated into two phases. If in-water work will extend beyond the
effective dates of the IHA, a second IHA application will be submitted
by the Navy. There will be a maximum of 110 days for vibratory pile
driving (seventy three days in phase I and thirty seven days in phase
II), and a contingent 20 days of impact pile driving. The specified
activities are expected to occur between October 1, 2016 and September
30, 2017.
Specific Geographic Region
NSM is located in northeastern Florida, at the mouth of the St.
Johns River and adjacent to the Atlantic Ocean (see Figures 2-1 and 2-2
of the Navy's application). The St. Johns River is the longest river in
Florida, with the final 35 mi flowing through the city of Jacksonville.
This portion of the river is significant for commercial shipping and
military use. At the mouth of the river, near the action area, the
Atlantic Ocean is the dominant influence and typical salinities are
above 30 ppm. Outside the river mouth, in nearshore waters, moderate
oceanic currents tend to flow southward parallel to the coast. Sea
surface temperatures range from around 16 [deg]C in winter to 28 [deg]C
in summer.
The specific action area consists of the NSM turning basin, an area
of approximately 2,000 by 3,000 ft containing ship berthing facilities
at sixteen locations along wharves around the basin perimeter. The
basin was constructed during the early 1940s by dredging the eastern
part of Ribault Bay (at the mouth of the St. Johns River), with dredge
material from the basin used to fill parts of the bay and other low-
lying areas in order to elevate the land surface. The basin is
currently maintained through regular dredging at a depth of 50 ft, with
depths at the berths ranging from 30-50 ft. The turning basin,
connected to the St. Johns River by a 500-ft-wide entrance channel,
will largely contain sound produced by project activities, with the
exception of sound propagating east into nearshore Atlantic waters
through the entrance channel (see Figure 2-2 of the Navy's
application). Bravo Wharf is located in the western corner of the
Mayport turning basin.
Detailed Description of Activities
In order to rehabilitate Bravo Wharf, the Navy proposes to install
a new steel sheet pile bulkhead at Bravo Wharf. The project consists of
installing a total of approximately 880 single sheet piles (Phase I--
berths B-2 and B-3: 590; Phase II--berth B-1: 290). The wall will be
anchored at the top and fill consisting of clean gravel and flowable
concrete fill will be placed behind the wall. A concrete cap will be
formed along the top and outside face of the wall to tie the entire
structure together and provide a berthing surface for vessels. The new
bulkhead will be designed for a fifty-year service life.
All piles would be driven by vibratory hammer, although impact pile
driving may be used as a contingency in cases when vibratory driving is
not sufficient to reach the necessary depth. In the unlikely event that
impact driving is required, either impact or vibratory driving could
occur on a given day, but concurrent use of vibratory and impact
drivers would not occur. The Navy estimates that a total of 130 in-
water work days may be required to complete pile driving activity,
which includes twenty days for contingency impact driving, if
necessary.
Description of Marine Mammals in the Area of the Specified Activity
There are four marine mammal species which may inhabit or transit
through the waters nearby NSM at the mouth of the St. Johns River and
in nearby nearshore Atlantic waters. These include the bottlenose
dolphin, Atlantic spotted dolphin (Stenella frontalis), North Atlantic
right whale (Eubalaena glacialis), and humpback whale (Megaptera
novaeangliae). Multiple additional cetacean species occur in South
Atlantic waters but would not be expected to occur in shallow nearshore
waters of the action area. Table 1 lists the marine mammal species with
expected potential for occurrence in the vicinity of NSM during the
project timeframe and summarizes key information regarding stock status
and abundance. Taxonomically, we follow Committee on Taxonomy (2014).
Please see NMFS' Stock Assessment Reports (SAR), available at
www.nmfs.noaa.gov/pr/sars, for more detailed accounts of these stocks'
status and abundance. Please also refer to NMFS' Web site
(www.nmfs.noaa.gov/pr/species/mammals) for generalized species accounts
and to the Navy's Marine Resource Assessment for the Charleston/
Jacksonville Operating Area, which documents and describes the marine
resources that occur in Navy operating areas of the Southeast (DoN,
2008). The document is publicly available at www.navfac.navy.mil/products_and_services/ev/products_and_services/marine_resources/marine_resource_assessments.html (accessed November 2, 2015).
In the species accounts provided here, we offer a brief
introduction to the species and relevant stock as well as available
information regarding population trends and threats, and
[[Page 75980]]
describe any information regarding local occurrence. Multiple stocks of
bottlenose dolphins may be present in the action area, either
seasonally or year-round, and are described further below. We first
address the three other species that may occur in the action area.
Table 1--Marine Mammals Potentially Present in the Vicinity of NSM
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Stock abundance (CV,
Species Stock ESA/MMPA status; Nmin, most recent PBR \3\ Annual M/ Relative occurrence;
strategic (Y/N) \1\ abundance survey) \2\ SI \4\ season of occurrence
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae
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North Atlantic right whale......... Western North Atlantic E/D; Y 476 (0; 476; 2013).... 1 4.3 Rare inshore, regular
\5\. near/offshore; Nov-
Apr.
Humpback whale..................... Gulf of Maine......... E/D; Y 823 (0; 823; 2008).... 2.7 7.6 Rare; Fall-Spring.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae
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Atlantic spotted dolphin........... Western North Atlantic -; N 44,715 (0.43; 31,610; 316 0 Rare; year-round.
2011).
Common bottlenose dolphin.......... Western North Atlantic -; N 77,532 (0.4; 56,053; 561 43.9 Rare; year-round.
Offshore. 2011).
Western North Atlantic -/D; Y 9,173 (0.46; 6,326; 63 0-12 Possibly common; \8\
Coastal, Southern 2010-11). Jan-Mar.
Migratory.
Western North Atlantic -/D; Y 1,219 (0.67; 730; 2010- 7 0.4 Possibly common; \8\
Coastal, Northern 11). year-round.
Florida.
Jacksonville Estuarine -; Y 412 \7\ (0.06; unk; undet. 1.2 Possibly common; \8\
System \6\. 1994-97). year-round.
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\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see
footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance
estimates are actual counts of animals and there is no associated CV. The most recent abundance survey that is reflected in the abundance estimate is
presented; there may be more recent surveys that have not yet been incorporated into the estimate.
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value. All
values presented here are from the draft 2015 SARs (www.nmfs.noaa.gov/pr/sars/draft.htm).
\5\ Abundance estimates (and resulting PBR values) for these stocks are new values presented in the draft 2015 SARs. This information was made available
for public comment and is currently under review and therefore may be revised prior to finalizing the 2015 SARs. However, we consider this information
to be the best available for use in this document.
\6\ Abundance estimates for these stocks are greater than eight years old and are therefore not considered current. PBR is considered undetermined for
these stocks, as there is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates
and PBR values, as these represent the best available information for use in this document.
\7\ This abundance estimate is considered an overestimate because it includes non- and seasonally-resident animals.
\8\ Bottlenose dolphins in general are common in the project area, but it is not possible to readily identify them to stock. Therefore, these three
stocks are listed as possibly common as we have no information about which stock commonly only occurs.
Northern Right whales occur in sub-polar to temperate waters in all
major ocean basins in the world with a clear migratory pattern,
occurring in high latitudes in summer (feeding) and lower latitudes in
winter (breeding). North Atlantic right whales exhibit extensive
migratory patterns, traveling along the eastern seaboard from calving
grounds off Georgia and northern Florida to northern feeding areas off
of the northeast U.S. and Canada in March/April and returning in
November/December. Migrations are typically within 30 nmi of the
coastline and in waters less than 50 m deep. Although this migratory
pattern is well known, winter distribution for most of the population--
the non-calving portion--is poorly known, as many whales are not
observed on the calving grounds. It is unknown where these animals
spend the winter, although they may occur further offshore or may
remain on foraging grounds during winter (Morano et al., 2012). During
the winter calving period, right whales occur regularly in offshore
waters of northeastern Florida. Critical habitat for right whales in
the southeast (as identified under the ESA) is designated to protect
calving grounds, and encompasses waters from the coast out to 15 nmi
offshore from Mayport. More rarely, right whales have been observed
entering the mouth of the St. Johns River for brief periods of time
(Schweitzer and Zoodsma, 2011). Right whales are not present in the
region outside of the winter calving season.
Humpback whales are a cosmopolitan species that migrate seasonally
between warm-water (tropical or sub-tropical) breeding and calving
areas in winter months and cool-water (temperate to sub-Arctic/
Antarctic) feeding areas in summer months (Gendron and Urban, 1993).
They tend to occupy shallow, coastal waters, although migrations are
[[Page 75981]]
undertaken through deep, pelagic waters. In the North Atlantic,
humpback whales are known to aggregate in six summer feeding areas
representing relatively discrete subpopulations (Clapham and Mayo,
1987), which share common wintering grounds in the Caribbean (and to a
lesser extent off of West Africa) (Winn et al., 1975; Mattila et al.,
1994; Palsb[oslash]ll et al., 1997; Smith et al., 1999; Stevick et al.,
2003; Cerchio et al., 2010). These populations or aggregations range
from the Gulf of Maine in the west to Norway in the east, and the
migratory range includes the east coast of the U.S. and Canada. The
only managed stock in U.S. waters is the Gulf of Maine feeding
aggregation, although other stocks occur in Canadian waters (e.g., Gulf
of St. Lawrence feeding aggregation), and it is possible that whales
from other stocks could occur in U.S. waters. Significant numbers of
whales do remain in mid- to high-latitude waters during the winter
months (Clapham et al., 1993; Swingle et al., 1993), and there have
been a number of humpback sightings in coastal waters of the
southeastern U.S. during the winter (Wiley et al., 1995; Laerm et al.,
1997; Waring et al., 2014). According to Waring et al. (2014), it is
unclear whether the increased numbers of sightings represent a
distributional change, or are simply due to an increase in sighting
effort and/or whale abundance. These factors aside, the humpback whale
remains relatively rare in U.S. coastal waters south of the mid-
Atlantic region, and is considered rare to extralimital in the action
area. Any occurrences in the region would be expected in fall, winter,
and spring during migration, as whales are unlikely to occur so far
south during the summer feeding season.
Neither the humpback whale nor the right whale would occur within
the turning basin, and only the right whale has been observed to occur
as far inshore as the mouth of the St. Johns River. Therefore, the
potential for interaction with these species is unlikely. When
considering frequency of occurrence, size of ensonified area (less than
one square kilometer during both vibratory (approximately 0.61 km\2\)
and impact driving (0.51 km\2\)), and duration (seventy three days in
phase I, and thirty seven days in phase II), we consider the
possibility for harassment of humpback and right whales to be
discountable. Therefore, the humpback whale and right whale are
excluded from further analysis and are not discussed further in this
document.
Atlantic spotted dolphins are distributed in tropical and warm
temperate waters of the western North Atlantic predominantly over the
continental shelf and upper slope, from southern New England through
the Gulf of Mexico (Leatherwood et al., 1976). Spotted dolphins in the
Atlantic Ocean and Gulf of Mexico are managed as separate stocks. The
Atlantic spotted dolphin occurs in two forms which may be distinct sub-
species (Perrin et al., 1987; Rice, 1998); a larger, more heavily
spotted form inhabits the continental shelf inside or near the 200-m
isobath and is the only form that would be expected to occur in the
action area. Although typically observed in deeper waters, spotted
dolphins of the western North Atlantic stock do occur regularly in
nearshore waters south of the Chesapeake Bay (Mullin and Fulling,
2003). Specific data regarding seasonal occurrence in the region of
activity is lacking, but higher numbers of individuals have been
reported to occur in nearshore waters of the Gulf of Mexico from
November to May, suggesting seasonal migration patterns (Griffin and
Griffin, 2003).
From recent observation reports from the Navy from previous
construction activity at Naval Station Mayport, no spotted dolphins
were observed. Similarly, dolphin research studies that have been
conducted in the area also reported zero observed spotted dolphins in
the project area (Gibson, pers. comm.). We consider the likelihood of
Atlantic spotted dolphins being impacted by the construction activities
to be discountable based on this information, combined with the zero
estimated exposures (density: 0.005240/km\2\). Therefore, spotted
dolphins are also excluded from further analysis and are not discussed
further in this document.
The following summarizes the population status and abundance of the
remaining species.
Bottlenose Dolphin
Bottlenose dolphins are found worldwide in tropical to temperate
waters and can be found in all depths from estuarine inshore to deep
offshore waters. Temperature appears to limit the range of the species,
either directly, or indirectly, for example, through distribution of
prey. Off North American coasts, common bottlenose dolphins are found
where surface water temperatures range from about 10 [deg]C to 32
[deg]C. In many regions, including the southeastern U.S., separate
coastal and offshore populations are known. There is significant
genetic, morphological, and hematological differentiation evident
between the two ecotypes (e.g., Walker, 1981; Duffield et al., 1983;
Duffield, 1987; Hoelzel et al., 1998), which correspond to shallow,
warm water and deep, cold water. Both ecotypes have been shown to
inhabit the western North Atlantic (Hersh and Duffield, 1990; Mead and
Potter, 1995), where the deep-water ecotype tends to be larger and
darker. In addition, several lines of evidence, including photo-
identification and genetic studies, support a distinction between
dolphins inhabiting coastal waters near the shore and those present in
the inshore waters of bays, sounds and estuaries. This complex
differentiation of bottlenose dolphin populations is observed
throughout the Atlantic and Gulf of Mexico coasts where bottlenose
dolphins are found, although estuarine populations have not been fully
defined.
In the Mayport area, four stocks of bottlenose dolphins are
currently managed, none of which are protected under the ESA. Of the
four stocks--offshore, southern migratory coastal, northern Florida
coastal, and Jacksonville estuarine system--only the latter three are
likely to occur in the action area. Bottlenose dolphins typically occur
in groups of 2-15 individuals (Shane et al., 1986; Kerr et al., 2005).
Although significantly larger groups have also been reported, smaller
groups are typical of shallow, confined waters. In addition, such
waters typically support some degree of regional site fidelity and
limited movement patterns (Shane et al., 1986; Wells et al., 1987).
Observations made during marine mammal surveys conducted during 2012-
2013 in the Mayport turning basin show bottlenose dolphins typically
occurring individually or in pairs, or less frequently in larger
groups. The maximum observed group size during these surveys is six,
while the mode is one. Navy observations indicate that bottlenose
dolphins rarely linger in a particular area in the turning basin, but
rather appear to move purposefully through the basin and then leave,
which likely reflects a lack of biological importance for these
dolphins in the basin. Based on currently available information, it is
not possible to determine the stock to which the dolphins occurring in
the action area may belong. These stocks are described in greater
detail below.
Western North Atlantic Offshore--This stock, consisting of the
deep-water ecotype or offshore form of bottlenose dolphin in the
western North Atlantic, is distributed primarily along the outer
continental shelf and continental slope, but has been documented to
occur relatively close to shore (Waring et al., 2014). The separation
between offshore and coastal morphotypes varies
[[Page 75982]]
depending on location and season, with the ranges overlapping to some
degree south of Cape Hatteras. Based on genetic analysis, Torres et al.
(2003) found a distributional break at 34 km from shore, with the
offshore form found exclusively seaward of 34 km and in waters deeper
than 34 m. Within 7.5 km of shore, all animals were of the coastal
morphotype. More recently, coastwide, systematic biopsy collection
surveys were conducted during the summer and winter to evaluate the
degree of spatial overlap between the two morphotypes. South of Cape
Hatteras, spatial overlap was found although the probability of a
sampled group being from the offshore morphotype increased with
increasing depth, and the closest distance for offshore animals was 7.3
km from shore, in water depths of 13 m just south of Cape Lookout
(Garrison et al., 2003). The maximum radial distance for the largest
ZOI is approximately 1.2 km (Table 3); therefore, it is unlikely that
any individuals of the offshore morphotype would be affected by project
activities. In terms of water depth, the affected area is generally in
the range of the shallower depth reported for offshore dolphins by
Garrison et al. (2003), but is far shallower than the depths reported
by Torres et al. (2003). South of Cape Lookout, the zone of spatial
overlap between offshore and coastal ecotypes is generally considered
to occur in water depths between 20-100 m (Waring et al., 2014), which
is generally deeper than waters in the action area. This stock is thus
excluded from further analysis.
Western North Atlantic Coastal, Southern Migratory--The coastal
morphotype of bottlenose dolphin is continuously distributed from the
Gulf of Mexico to the Atlantic and north approximately to Long Island
(Waring et al., 2014). On the Atlantic coast, Scott et al. (1988)
hypothesized a single coastal stock, citing stranding patterns during a
high mortality event in 1987-88 and observed density patterns. More
recent studies demonstrate that there is instead a complex mosaic of
stocks (Zolman, 2002; McLellan et al., 2002; Rosel et al., 2009). The
coastal morphotype was managed by NMFS as a single stock until 2009,
when it was split into five separate stocks, including northern and
southern migratory stocks. The original, single stock of coastal
dolphins recognized from 1995-2001 was listed as depleted under the
MMPA as a result of a 1987-88 mortality event. That designation was
retained when the single stock was split into multiple coastal stocks.
Therefore, all coastal stocks of bottlenose dolphins are listed as
depleted under the MMPA, and are also considered strategic stocks.
According to the Scott et al. (1988) hypothesis, a single stock was
thought to migrate seasonally between New Jersey (summer) and central
Florida (winter). Instead, it was more recently determined that a mix
of resident and migratory stocks exists, with the migratory movements
and spatial distribution of the southern migratory stock the most
poorly understood of these. Stable isotope analysis and telemetry
studies provide evidence for seasonal movements of dolphins between
North Carolina and northern Florida (Knoff, 2004; Waring et al., 2014),
and genetic analyses and tagging studies support differentiation of
northern and southern migratory stocks (Rosel et al., 2009; Waring et
al., 2014). Although there is significant uncertainty regarding the
southern migratory stock's spatial movements, telemetry data indicates
that the stock occupies waters of southern North Carolina (south of
Cape Lookout) during the fall (October-December). In winter months
(January-March), the stock moves as far south as northern Florida where
it overlaps spatially with the northern Florida coastal and
Jacksonville estuarine system stocks. In spring (April-June), the stock
returns north to waters of North Carolina, and is presumed to remain
north of Cape Lookout during the summer months. Therefore, the
potential exists for harassment of southern migratory dolphins, most
likely during the winter only.
Bottlenose dolphins are ubiquitous in coastal waters from the mid-
Atlantic through the Gulf of Mexico, and therefore interact with
multiple coastal fisheries, including gillnet, trawl, and trap/pot
fisheries. Stock-specific total fishery-related mortality and serious
injury cannot be directly estimated because of the spatial overlap
among stocks of bottlenose dolphins, as well as because of unobserved
fisheries. The primary known source of fishery mortality for the
southern migratory stock is the mid-Atlantic gillnet fishery (Waring et
al., 2014). Between 2004 and 2008, 588 bottlenose dolphins stranded
along the Atlantic coast between Florida and Maryland that could
potentially be assigned to the southern migratory stock, although the
assignment of animals to a particular stock is impossible in some
seasons and regions due to spatial overlap amongst stocks (Waring et
al., 2014). Many of these animals exhibited some evidence of human
interaction, such as line/net marks, gunshot wounds, or vessel strike.
In addition, nearshore and estuarine habitats occupied by the coastal
morphotype are adjacent to areas of high human population and some are
highly industrialized. It should also be noted that stranding data
underestimate the extent of fishery-related mortality and serious
injury because not all of the marine mammals that die or are seriously
injured in fishery interactions are discovered, reported or
investigated, nor will all of those that are found necessarily show
signs of entanglement or other fishery interaction. The level of
technical expertise among stranding network personnel varies widely as
does the ability to recognize signs of fishery interactions. Finally,
multiple resident populations of bottlenose dolphins have been shown to
have high concentrations of organic pollutants (e.g., Kuehl et al.,
1991) and, despite little study of contaminant loads in migrating
coastal dolphins, exposure to environmental pollutants and subsequent
effects on population health is an area of concern and active research.
Western North Atlantic Coastal, Northern Florida--Please see above
for description of the differences between coastal and offshore
ecotypes and the delineation of coastal dolphins into management
stocks. The northern Florida coastal stock is one of five stocks of
coastal dolphins and one of three known resident stocks (other resident
stocks include South Carolina/Georgia and central Florida dolphins).
The spatial extent of these stocks, their potential seasonal movements,
and their relationships with estuarine stocks are poorly understood.
During summer months, when the migratory stocks are known to be in
North Carolina waters and further north, bottlenose dolphins are still
seen in coastal waters of South Carolina, Georgia and Florida,
indicating the presence of additional stocks of coastal animals.
Speakman et al. (2006) documented dolphins in coastal waters off
Charleston, South Carolina, that are not known resident members of the
estuarine stock, and genetic analyses indicate significant differences
between coastal dolphins from northern Florida, Georgia and central
South Carolina (NMFS, 2001; Rosel et al., 2009). The northern Florida
stock is thought to be present from approximately the Georgia-Florida
border south to 29.4[deg] N. (Waring et al., 2014).
The northern Florida coastal stock ventures into the St. Johns
River in large numbers, but rarely moves past Naval Station Mayport.
The mouth of the St. Johns River may serve as a foraging area for this
stock and the Jacksonville estuarine stock (Gibson, pers. comm).
[[Page 75983]]
The northern Florida coastal stock is susceptible to interactions
with similar fisheries as those described above for the southern
migratory stock, including gillnet, trawl, and trap/pot fisheries. From
2004-08, 78 stranded dolphins were recovered in northern Florida
waters, although it was not possible to determine whether there was
evidence of human interaction for the majority of these (Waring et al.,
2014). The same concerns discussed above regarding underestimation of
mortality hold for this stock and, as for southern migratory dolphins,
pollutant loading is a concern.
Jacksonville Estuarine System--Please see above for description of
the differences between coastal and offshore ecotypes and the
delineation of coastal dolphins into management stocks primarily
inhabiting nearshore waters. The coastal morphotype of bottlenose
dolphin is also resident to certain inshore estuarine waters (Caldwell,
2001; Gubbins, 2002; Zolman, 2002; Gubbins et al., 2003). Multiple
lines of evidence support demographic separation between coastal
dolphins found in nearshore waters and those in estuarine waters, as
well as between dolphins residing within estuaries along the Atlantic
and Gulf coasts (e.g., Wells et al., 1987; Scott et al., 1990; Wells et
al., 1996; Cortese, 2000; Zolman, 2002; Speakman, et al. 2006; Stolen
et al., 2007; Balmer et al., 2008; Mazzoil et al., 2008). In
particular, a study conducted near Jacksonville demonstrated
significant genetic differences between coastal and estuarine dolphins
(Caldwell, 2001; Rosel et al., 2009). Despite evidence for genetic
differentiation between estuarine and nearshore populations, the degree
of spatial overlap between these populations remains unclear. Photo-
identification studies within estuaries demonstrate seasonal
immigration and emigration and the presence of transient animals (e.g.,
Speakman et al., 2006). In addition, the degree of movement of resident
estuarine animals into coastal waters on seasonal or shorter time
scales is poorly understood (Waring et al., 2014).
The Jacksonville estuarine system (JES) stock has been defined as
separate primarily by the results of photo-identification and genetic
studies. The stock range is considered to be bounded in the north by
the Georgia-Florida border at Cumberland Sound, extending south to
approximately Jacksonville Beach, Florida. This encompasses an area
defined during a photo-identification study of bottlenose dolphin
residency patterns in the area (Caldwell, 2001), and the borders are
subject to change upon further study of dolphin residency patterns in
estuarine waters of southern Georgia and northern/central Florida. The
habitat is comprised of several large brackish rivers, including the
St. Johns River, as well as tidal marshes and shallow riverine systems.
Three behaviorally different communities were identified during
Caldwell's (2001) study: The estuarine waters north (Northern) and
south (Southern) of the St. Johns River and the coastal area, all of
which differed in density, habitat fidelity and social affiliation
patterns. The coastal dolphins are believed to be members of a coastal
stock, however (Waring et al., 2014). Although Northern and Southern
members of the JES stock show strong site fidelity, members of both
groups have been observed outside their preferred areas. Dolphins
residing within estuaries south of Jacksonville Beach down to the
northern boundary of the Indian River Lagoon Estuarine System (IRLES)
stock are currently not included in any stock, as there are
insufficient data to determine whether animals in this area exhibit
affiliation to the JES stock, the IRLES stock, or are simply transient
animals associated with coastal stocks. Further research is needed to
establish affinities of dolphins in the area between the ranges, as
currently understood, of the JES and IRLES stocks.
The JES stock is susceptible to similar fisheries interactions as
those described above for coastal stocks, although only trap/pot
fisheries are likely to occur in estuarine waters frequented by the
stock. Only one dolphin carcass bearing evidence of fisheries
interaction was recovered during 2003-07 in the JES area, and an
additional sixteen stranded dolphins were recovered during this time,
but no determinations regarding human interactions could be made for
the majority (Waring et al., 2014). Nineteen bottlenose dolphins died
in the St. Johns River (SJR), Florida between May 24 and November 7,
2010, all of which came from the JES stock. The cause of these deaths
was undetermined. The same concerns discussed above regarding
underestimation of mortality hold for this stock and, as for stocks
discussed above, pollutant loading is a concern. Although no
contaminant analyses have yet been conducted in this area, the JES
stock inhabits areas with significant drainage from industrial and
urban sources, and as such is exposed to contaminants in runoff from
these. In other estuarine areas where such analyses have been
conducted, exposure to anthropogenic contaminants has been found to
likely have an effect (Hansen et al. 2004; Schwacke et al., 2004; Reif
et al., 2008).
The original, single stock of coastal dolphins recognized from
1995-2001 was listed as depleted under the MMPA as a result of a 1987-
88 mortality event. That designation was retained when the single stock
was split into multiple coastal stocks. However, Scott et al. (1988)
suggested that dolphins residing in the bays, sounds and estuaries
adjacent to these coastal waters were not affected by the mortality
event and these animals were explicitly excluded from the depleted
listing (Waring et al., 2014). Gubbins et al. (2003), using data from
Caldwell (2001), estimated the stock size to be 412 (CV = 0.06).
However, NMFS considers abundance unknown because this estimate likely
includes an unknown number of non-resident and seasonally-resident
dolphins. It nevertheless represents the best available information
regarding stock size. Because the stock size is likely small, and
relatively few mortalities and serious injuries would exceed PBR, the
stock is considered to be a strategic stock (Waring et al., 2014).
An unusual mortality event (UME) occurred between 2013 and 2015
spanning the Atlantic coast, which impacted all stocks of bottlenose
dolphins in the area. Over 1,800 dolphins stranded in this time period.
The preliminary conclusion of the cause of this UME was morbillivirus.
The bottlenose dolphin stocks in this area (SJR and coastal areas) may
be considered vulnerable to impacts from future activities due to this
recent event.
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity (e.g., sound produced by pile
driving) may impact marine mammals and their habitat. The Estimated
Take by Incidental Harassment section later in this document will
include a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
section will include an analysis of how this specific activity will
impact marine mammals and will consider the content of this section,
the Estimated Take by Incidental Harassment section and the Proposed
Mitigation section to draw conclusions regarding the likely impacts of
this activity on the reproductive success or survivorship of
individuals and from that on the affected marine mammal populations or
stocks. In the following discussion, we provide general background
information on
[[Page 75984]]
sound and marine mammal hearing before considering potential effects to
marine mammals from sound produced by vibratory and impact pile
driving.
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 and attenuate
(decrease) 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 between a
measured pressure (with sound) and a reference pressure (sound at a
constant pressure, established by scientific standards). It 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. Note that all underwater sound levels in this document are
referenced to a pressure of 1 [micro]Pa and all airborne sound levels
in this document are referenced to a pressure of 20 [mu]Pa.
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, 1983). 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.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown 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). A number of
sources contribute to ambient sound, 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 noise 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 noise becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total noise at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient noise levels, as can some fish and shrimp. The frequency band
for biological contributions is from approximately 12 Hz to over 100
kHz.
Anthropogenic: Sources of ambient noise 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. Shipping noise
typically dominates the total ambient noise 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
attenuate rapidly (Richardson et al., 1995). Sound from identifiable
anthropogenic sources other than the activity of interest (e.g., a
passing vessel) is sometimes termed background sound, as opposed to
ambient sound.
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, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
The underwater acoustic environment in the Mayport turning basin is
likely to be dominated by noise from day-to-day port and vessel
activities. The basin is sheltered from most wave noise, but is a high-
use area for naval ships, tugboats, and security vessels. When
underway, these sources can create noise between 20 Hz and 16 kHz
(Lesage et al., 1999), with broadband noise levels up to 180 dB. While
there are no current measurements of ambient noise levels in the
turning basin, it is likely that levels within the basin periodically
exceed the 120 dB threshold and, therefore, that the high levels of
anthropogenic activity in the basin create an environment far different
from quieter habitats where behavioral reactions to sounds around the
120 dB threshold have been observed (e.g., Malme et al., 1984, 1988).
In-water construction activities associated with the project would
include impact pile driving and vibratory pile driving. The sounds
produced by these activities fall into one of two general sound types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two 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
[[Page 75985]]
Southall et al., (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) 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 rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Impact hammers 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 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 (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals,
and exposure to sound can have deleterious effects. To appropriately
assess these potential effects, it is necessary to understand the
frequency ranges marine mammals are able to hear. Current data indicate
that not all marine mammal species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008). To reflect this, Southall et al. (2007) recommended
that marine mammals be divided into functional hearing groups based on
measured or estimated hearing ranges on the basis of available
behavioral data, audiograms derived using auditory evoked potential
techniques, anatomical modeling, and other data. The lower and/or upper
frequencies for some of these functional hearing groups have been
modified from those designated by Southall et al. (2007). The
functional groups and the associated frequencies are indicated below
(note that these frequency ranges do not necessarily correspond to the
range of best hearing, which varies by species):
Low-frequency cetaceans (mysticetes): Functional hearing
is estimated to occur between approximately 7 Hz and 25 kHz (extended
from 22 kHz; Watkins, 1986; Au et al., 2006; Lucifredi and Stein, 2007;
Ketten and Mountain, 2009; Tubelli et al., 2012);
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Functional hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; now considered to
include two members of the genus Lagenorhynchus on the basis of recent
echolocation data and genetic data [May-Collado and Agnarsson, 2006;
Kyhn et al. 2009, 2010; Tougaard et al. 2010]): 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 to 100 kHz for Phocidae (true seals)
and between 100 Hz and 40 kHz for Otariidae (eared seals), with the
greatest sensitivity between approximately 700 Hz and 20 kHz. The
pinniped functional hearing group was modified from Southall et al.
(2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013).
One cetacean species is expected to potentially be affected by the
specified activity. Bottlenose dolphins are classified as mid-frequency
cetaceans.
Acoustic Effects, Underwater
Potential Effects of Pile Driving Sound--The effects of sounds from
pile driving might result in one or more of the following: Temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, and masking (Richardson et al., 1995;
Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007). The
effects of pile driving on marine mammals are dependent on several
factors, including the size, type, and depth of the animal; the depth,
intensity, and duration of the pile driving sound; the depth of the
water column; the substrate of the habitat; the standoff distance
between the pile and the animal; and the sound propagation properties
of the environment. Impacts to marine mammals from pile driving
activities are expected to result primarily from acoustic pathways. As
such, the degree of effect is intrinsically related to the received
level and duration of the sound exposure, which are in turn influenced
by the distance between the animal and the source. The further away
from the source, the less intense the exposure should be. The substrate
and depth of the habitat affect the sound propagation properties of the
environment. Shallow environments are typically more structurally
complex, which leads to rapid sound attenuation. In addition,
substrates that are soft (e.g., sand) would absorb or attenuate the
sound more readily than hard substrates (e.g., rock) which may reflect
the acoustic wave. Soft porous substrates would also likely require
less time to drive the pile, and possibly less forceful equipment,
which would ultimately decrease the intensity of the acoustic source.
In the absence of mitigation, impacts to marine species would be
expected to result from physiological and behavioral responses to both
the type and strength of the acoustic signature (Viada et al., 2008).
The type and severity of behavioral impacts are more difficult to
define due to limited studies addressing the behavioral effects of
impulsive sounds on marine mammals. Potential effects from impulsive
sound sources can range in severity from effects such as behavioral
disturbance or tactile perception to physical discomfort, slight injury
of the internal organs and the auditory system, or mortality (Yelverton
et al., 1973).
Hearing Impairment and Other Physical Effects--Marine mammals
exposed to high intensity sound repeatedly or for prolonged periods can
experience hearing threshold shift (TS), which is the loss of hearing
sensitivity
[[Page 75986]]
at certain frequency ranges (Kastak et al., 1999; Schlundt et al.,
2000; Finneran et al., 2002, 2005). TS can be permanent (PTS), in which
case the loss of hearing sensitivity is not recoverable, or temporary
(TTS), in which case the animal's hearing threshold would recover over
time (Southall et al., 2007). Marine mammals depend on acoustic cues
for vital biological functions, (e.g., orientation, communication,
finding prey, avoiding predators); thus, TTS may result in reduced
fitness in survival and reproduction. However, this depends on the
frequency and duration of TTS, as well as the biological context in
which it occurs. TTS of limited duration, occurring in a frequency
range that does not coincide with that used for recognition of
important acoustic cues, would have little to no effect on an animal's
fitness. Repeated sound exposure that leads to TTS could cause PTS. PTS
constitutes injury (direct auditory tissue effects), but TTS does not
(Southall et al., 2007). The following subsections discuss in somewhat
more detail the possibilities of TTS, PTS, and non-auditory physical
effects.
Temporary Threshold Shift--TTS 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. In terrestrial mammals, TTS can
last from minutes or hours to days (in cases of strong TTS). 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. 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. Available data on TTS in marine mammals are summarized in
Southall et al. (2007).
Given the available data, the received level of a single pulse
(with no frequency weighting) might need to be approximately 186 dB re
1 [mu]Pa\2\-s (i.e., 186 dB sound exposure level [SEL] or approximately
221-226 dB p-p [peak]) in order to produce brief, mild TTS. Exposure to
several strong pulses that each have received levels near 190 dB rms
(175-180 dB SEL) might result in cumulative exposure of approximately
186 dB SEL and thus slight TTS in a small odontocete, assuming the TTS
threshold is (to a first approximation) a function of the total
received pulse energy.
The above TTS information for odontocetes is derived from studies
on the bottlenose dolphin and beluga whale (Delphinapterus leucas).
There is no published TTS information for other species of cetaceans.
However, preliminary evidence from a harbor porpoise exposed to pulsed
sound suggests that its TTS threshold may have been lower (Lucke et
al., 2009). As summarized above, data that are now available imply that
TTS is unlikely to occur unless odontocetes are exposed to pile driving
pulses stronger than 180 dB re 1 [mu]Pa rms.
Permanent Threshold Shift--When PTS occurs, there is physical
damage to the sound receptors in the ear. In severe cases, there can be
total or partial deafness, while in other cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985). There is no specific evidence that exposure to pulses of sound
can cause PTS in any marine mammal. However, given the possibility that
mammals close to a sound source might incur TTS, there has been further
speculation about the possibility that some individuals might incur
PTS. Single or occasional occurrences of mild TTS are not indicative of
permanent auditory damage, but repeated or (in some cases) single
exposures to a level well above that causing TTS onset might elicit
PTS.
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 if the animal were
exposed to strong sound pulses with rapid rise time. Based on data from
terrestrial mammals, a precautionary assumption is that the PTS
threshold for impulse sounds (such as pile driving pulses as received
close to the source) is at least 6 dB higher than the TTS threshold on
a peak-pressure basis and probably greater than 6 dB (Southall et al.,
2007). On an SEL basis, Southall et al. (2007) estimated that received
levels would need to exceed the TTS threshold by at least 15 dB for
there to be risk of PTS. Thus, for cetaceans, Southall et al. (2007)
estimate that the PTS threshold might be an M-weighted SEL (for the
sequence of received pulses) of approximately 198 dB re 1 [mu]Pa\2\-s
(15 dB higher than the TTS threshold for an impulse). Given the higher
level of sound necessary to cause PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Measured source levels from impact pile driving can be as high as
214 dB rms. Although no marine mammals have been shown to experience
TTS or PTS as a result of being exposed to pile driving activities,
captive bottlenose dolphins and beluga whales exhibited changes in
behavior when exposed to strong pulsed sounds (Finneran et al., 2000,
2002, 2005). The animals tolerated high received levels of sound before
exhibiting aversive behaviors. Experiments on a beluga whale showed
that exposure to a single watergun impulse at a received level of 207
kPa (30 psi) p-p, which is equivalent to 228 dB p-p, resulted in a 7
and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, respectively.
Thresholds returned to within 2 dB of the pre-exposure level within
four minutes of the exposure (Finneran et al., 2002). Although the
source level of pile driving from one hammer strike is expected to be
much lower than the single watergun impulse cited here, animals being
exposed for a prolonged period to repeated hammer strikes could receive
more sound exposure in terms of SEL than from the single watergun
impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the aforementioned
experiment (Finneran et al., 2002). However, in order for marine
mammals to experience TTS or PTS, the animals have to be close enough
to be exposed to high intensity sound levels for a prolonged period of
time. Based on the best scientific information available, these SPLs
are far below the thresholds that could cause TTS or the onset of PTS.
Non-auditory Physiological Effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to strong underwater sound include stress, neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies
examining such effects are limited. In general, little is known about
the potential for pile driving to cause auditory impairment or other
physical effects in marine mammals. Available data suggest that such
effects, if they occur at all, would presumably be limited to short
distances from the sound source and to activities that extend over a
prolonged period. The available data do not allow identification of a
specific exposure level above which non-auditory effects can be
expected (Southall et al., 2007) or any meaningful quantitative
predictions of the numbers (if any) of marine mammals that might be
affected in those ways. Marine mammals that show behavioral avoidance
of pile driving, including some odontocetes and some pinnipeds, are
especially unlikely to incur auditory impairment or non-auditory
physical effects.
[[Page 75987]]
Disturbance Reactions
Disturbance includes a variety of effects, including subtle changes
in behavior, more conspicuous changes in activities, and displacement.
Behavioral responses to sound are highly variable and context-specific
and reactions, if any, depend on species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day, and many other factors (Richardson et al., 1995; Wartzok
et al., 2003; Southall et al., 2007).
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. Behavioral state may affect the type of response as well. For
example, animals that are resting may show greater behavioral change in
response to disturbing sound levels than animals that are highly
motivated to remain in an area for feeding (Richardson et al., 1995;
NRC, 2003; Wartzok et al., 2003).
Controlled experiments with captive marine mammals showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources
(typically seismic guns or acoustic harassment devices, but also
including pile driving) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; Thorson and Reyff, 2006; see also Gordon et al., 2003;
Wartzok et al., 2003; Nowacek et al., 2007). Responses to continuous
sound, such as vibratory pile installation, have not been documented as
well as responses to pulsed sounds.
With both types of pile driving, it is likely that the onset of
pile driving could result in temporary, short term changes in an
animal's typical behavior and/or avoidance of the affected area. These
behavioral changes may include (Richardson et al., 1995): Changing
durations of surfacing and dives, number of blows per surfacing, or
moving direction and/or speed; reduced/increased vocal activities;
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping); avoidance of
areas where sound sources are located; and/or flight responses (e.g.,
pinnipeds flushing into water from haul-outs or rookeries). Pinnipeds
may increase their haul-out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, or reproduction. Significant
behavioral modifications that could potentially lead to effects on
growth, survival, or reproduction include:
Drastic changes in diving/surfacing patterns (such as
those thought to cause beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al., 2007).
Auditory Masking
Natural and artificial sounds can disrupt behavior by masking, or
interfering with, a marine mammal's ability to hear other sounds.
Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher levels. Chronic exposure to excessive, though not high-
intensity, sound could cause masking at particular frequencies for
marine mammals, which utilize sound for vital biological functions.
Masking can interfere with detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, under certain circumstances,
marine mammals whose acoustical sensors or environment are being
severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. If the coincident
(masking) sound were man-made, it could be potentially harassing if it
disrupted hearing-related behavior. It is important to distinguish TTS
and PTS, which persist after the sound exposure, from masking, which
occurs during the sound exposure. Because masking (without resulting in
TS) is not associated with abnormal physiological function, it is not
considered a physiological effect, but rather a potential behavioral
effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. Because sound
generated from in-water pile driving is mostly concentrated at low
frequency ranges, it may have less effect on high frequency
echolocation sounds made by porpoises. However, lower frequency man-
made sounds are more likely to affect detection of communication calls
and other potentially important natural sounds such as surf and prey
sound. It may also affect communication signals when they occur near
the sound band and thus reduce the communication space of animals
(e.g., Clark et al., 2009) and cause increased stress levels (e.g.,
Foote et al., 2004; Holt et al., 2009).
Masking has the potential to impact species at the population or
community levels as well as at individual levels. Masking affects both
senders and receivers of the signals and can potentially have long-term
chronic effects on marine mammal species and populations. Recent
research suggests that low frequency ambient sound levels have
increased by as much as 20 dB (more than three times in terms of SPL)
in the world's ocean from pre-industrial periods, and that most of
these increases are from distant shipping (Hildebrand, 2009). All
anthropogenic sound sources, such as those from vessel traffic, pile
driving, and dredging activities, contribute to the elevated ambient
sound levels, thus intensifying masking.
The most intense underwater sounds in the proposed action are those
produced by impact pile driving. Given that the energy distribution of
pile driving covers a broad frequency spectrum, sound from these
sources would likely be within the audible range of marine mammals
present in the project area. Impact pile driving activity is relatively
short-term, with rapid pulses occurring for approximately fifteen
minutes per pile. The probability for impact pile driving resulting
from this proposed action masking acoustic signals important to the
behavior and survival of marine mammal species is likely to be
negligible. Vibratory pile driving is also relatively short-term, with
rapid oscillations occurring for approximately one and a half hours per
pile. It is possible that vibratory pile driving resulting from this
proposed action may mask acoustic signals important to the behavior and
survival of marine mammal species, but the
[[Page 75988]]
short-term duration and limited affected area would result in
insignificant impacts from masking. Any masking event that could
possibly rise to Level B harassment under the MMPA would occur
concurrently within the zones of behavioral harassment already
estimated for vibratory and impact pile driving, and which have already
been taken into account in the exposure analysis.
Anticipated Effects on Habitat
The proposed activities at NSM would not result in permanent
impacts to habitats used directly by marine mammals, but may have
potential short-term impacts to food sources such as forage fish and
may affect acoustic habitat (see masking discussion above). There are
no known foraging hotspots or other ocean bottom structure of
significant biological importance to marine mammals present in the
marine waters of the project area; however the surrounding areas may be
foraging habitat for the dolphins. Therefore, the main impact issue
associated with the proposed activity would be temporarily elevated
sound levels and the associated direct effects on marine mammals, as
discussed previously in this document. The most likely impact to marine
mammal habitat occurs from pile driving effects on likely marine mammal
prey (i.e., fish) within NSM and minor impacts to the immediate
substrate during installation and removal of piles during the wharf
construction project.
Pile Driving Effects on Potential Prey (Fish)
Construction activities may produce both pulsed (i.e., impact pile
driving) and continuous (i.e., vibratory pile driving) sounds. Fish
react to sounds which are especially strong and/or intermittent low-
frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution. Hastings and
Popper (2005) identified several studies that suggest fish may relocate
to avoid certain areas of sound energy. Additional studies have
documented effects of pile driving (or other types of sounds) on fish,
although several are based on studies in support of large, multiyear
bridge construction projects (e.g., Scholik and Yan, 2001, 2002; Popper
and Hastings, 2009). Sound pulses at received levels of 160 dB re 1
[mu]Pa may cause subtle changes in fish behavior. SPLs of 180 dB may
cause noticeable changes in behavior (Pearson et al., 1992; Skalski et
al., 1992). SPLs of sufficient strength have been known to cause injury
to fish and fish mortality. The most likely impact to fish from pile
driving activities at the project area would be temporary behavioral
avoidance of the area. The duration of fish avoidance of this area
after pile driving stops is unknown, but a rapid return to normal
recruitment, distribution and behavior is anticipated. In general,
impacts to marine mammal prey species are expected to be minor and
temporary due to the short timeframe for the project.
Pile Driving Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in nearshore and estuarine waters in
the region. Avoidance by potential prey (i.e., fish) of the immediate
area due to the temporary loss of this foraging habitat is also
possible. The duration of fish avoidance of this area after pile
driving stops is unknown, but a rapid return to normal recruitment,
distribution and behavior is anticipated. Any behavioral avoidance by
fish of the disturbed area would still leave significantly large areas
of fish and marine mammal foraging habitat in the nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Therefore, pile driving is not likely
to have a permanent, adverse effect on marine mammal foraging habitat
at the project area. The Mayport turning basin itself is a man-made
basin with significant levels of industrial activity and regular
dredging, and is unlikely to harbor significant amounts of forage fish.
Thus, any impacts to marine mammal habitat are not expected to cause
significant or long-term consequences for individual marine mammals or
their populations.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its 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.
Measurements from similar pile driving events were coupled with
practical spreading loss to estimate zones of influence (ZOI; see
Estimated Take by Incidental Harassment); these values were used to
develop mitigation measures for pile driving activities at NSM. The
ZOIs effectively represent the mitigation zone that would be
established around each pile to prevent Level A harassment to marine
mammals, while providing estimates of the areas within which Level B
harassment might occur. In addition to the specific measures described
later in this section, the Navy would conduct briefings between
construction supervisors and crews, marine mammal monitoring team, and
Navy staff prior to the start of all pile driving activity, and when
new personnel join the work, in order to explain responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures.
Monitoring and Shutdown for Pile Driving
The following measures would apply to the Navy's mitigation through
shutdown and disturbance zones:
Shutdown Zone--For all pile driving activities, the Navy will
establish a shutdown zone intended to contain the area in which SPLs
equal or exceed the 190 dB rms acoustic injury criteria. The purpose of
a shutdown zone is to define an area within which shutdown of activity
would occur upon sighting of a marine mammal (or in anticipation of an
animal entering the defined area), thus preventing injury of marine
mammals (as described previously under Potential Effects of the
Specified Activity on Marine Mammals, serious injury or death are
unlikely outcomes even in the absence of mitigation measures). Modeled
radial distances for shutdown zones are shown in Table 3. However, a
minimum shutdown zone of 15 m (which is larger than the maximum
predicted injury zone) will be established during all pile driving
activities, regardless of the estimated zone. Vibratory pile driving
activities are not predicted to produce sound exceeding the 190-dB
Level A harassment threshold, but these precautionary measures are
intended to prevent the already unlikely possibility of physical
interaction with construction equipment and to further reduce any
possibility of acoustic injury. For impact driving of steel piles, if
necessary, the radial distance of the shutdown would be established at
40 m.
Disturbance Zone--Disturbance zones are the areas in which SPLs
equal or exceed 160 and 120 dB rms (for impulse and continuous sound,
respectively). Disturbance zones provide utility for monitoring
conducted for mitigation purposes (i.e., shutdown zone monitoring) by
establishing monitoring
[[Page 75989]]
protocols for areas adjacent to the shutdown zones. Monitoring of
disturbance zones enables observers to be aware of and communicate the
presence of marine mammals in the project area but outside the shutdown
zone and thus prepare for potential shutdowns of activity. However, the
primary purpose of disturbance zone monitoring is for documenting
incidents of Level B harassment; disturbance zone monitoring is
discussed in greater detail later (see Proposed Monitoring and
Reporting). Nominal radial distances for disturbance zones are shown in
Table 3. Given the size of the disturbance zone for vibratory pile
driving, it is impossible to guarantee that all animals would be
observed or to make comprehensive observations of fine-scale behavioral
reactions to sound, and only a portion of the zone (e.g., what may be
reasonably observed by visual observers stationed within the turning
basin) would be observed.
In order to document observed incidents of harassment, monitors
record all marine mammal observations, regardless of location. The
observer's location, as well as the location of the pile being driven,
is known from a GPS. The location of the animal is estimated as a
distance from the observer, which is then compared to the location from
the pile. It may then be estimated whether the animal was exposed to
sound levels constituting incidental harassment on the basis of
predicted distances to relevant thresholds in post-processing of
observational and acoustic data, and a precise accounting of observed
incidences of harassment created. This information may then be used to
extrapolate observed takes to reach an approximate understanding of
actual total takes.
Monitoring Protocols--Monitoring would be conducted before, during,
and after pile driving activities. In addition, observers shall record
all incidents of marine mammal occurrence, regardless of distance from
activity, and shall document any behavioral reactions in concert with
distance from piles being driven. Observations made outside the
shutdown zone will not result in shutdown; that pile segment would be
completed without cessation, unless the animal approaches or enters the
shutdown zone, at which point all pile driving activities would be
halted. Monitoring will take place from fifteen minutes prior to
initiation through thirty minutes post-completion of pile driving
activities. Pile driving activities include the time to install or
remove a single pile or series of piles, as long as the time elapsed
between uses of the pile driving equipment is no more than thirty
minutes. Please see the Monitoring Plan (www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), developed by the Navy in agreement with
NMFS, for full details of the monitoring protocols.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Qualified observers
are typically trained biologists, with the following minimum
qualifications:
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;
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 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; and
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.
(2) Prior to the start of pile driving activity, the shutdown zone
will be monitored for fifteen minutes to ensure that it is clear of
marine mammals. Pile driving will only commence once observers have
declared the shutdown zone clear of marine mammals; animals will be
allowed to remain in the shutdown zone (i.e., must leave of their own
volition) and their behavior will be monitored and documented. The
shutdown zone may only be declared clear, and pile driving started,
when the entire shutdown zone is visible (i.e., when not obscured by
dark, rain, fog, etc.). In addition, if such conditions should arise
during impact pile driving that is already underway, the activity would
be halted.
(3) If a marine mammal approaches or enters the shutdown zone
during the course of pile driving operations, activity will be halted
and delayed until either the animal has voluntarily left and been
visually confirmed beyond the shutdown zone or fifteen minutes have
passed without re-detection of the animal. Monitoring will be conducted
throughout the time required to drive a pile.
Soft Start
The use of a soft start procedure is believed to provide additional
protection to marine mammals by warning or providing a chance to leave
the area prior to the hammer operating at full capacity, and typically
involves a requirement to initiate sound from the hammer at reduced
energy followed by a waiting period. This procedure is repeated two
additional times. It is difficult to specify the reduction in energy
for any given hammer because of variation across drivers and, for
impact hammers, the actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes.'' For impact driving, we require an initial set of
three strikes from the impact hammer at reduced energy, followed by a
thirty-second waiting period, then two subsequent three strike sets.
Soft start will be required at the beginning of each day's impact pile
driving work and at any time following a cessation of impact pile
driving of thirty minutes or longer.
We have carefully evaluated the Navy's proposed mitigation measures
and considered their effectiveness in past implementation to
preliminarily determine whether they are likely to effect the least
practicable 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: (1)
The manner in which, and the degree to which, the successful
implementation of the measure is expected to minimize adverse impacts
to marine mammals, (2) the proven or likely efficacy of the specific
measure to minimize adverse impacts as planned; and (3) the
practicability of the measure for applicant implementation.
Any mitigation measure(s) we prescribe should be able to
accomplish, have a reasonable likelihood of
[[Page 75990]]
accomplishing (based on current science), or contribute to the
accomplishment of one or more of the general goals listed below:
(1) Avoidance or minimization of injury or death of marine mammals
wherever possible (goals 2, 3, and 4 may contribute to this goal).
(2) A reduction in the number (total number or number at
biologically important time or location) of individual marine mammals
exposed to stimuli expected to result in incidental take (this goal may
contribute to 1, above, or to reducing takes by behavioral harassment
only).
(3) A reduction in the number (total number or number at
biologically important time or location) of times any individual marine
mammal would be exposed to stimuli expected to result in incidental
take (this goal may contribute to 1, above, or to reducing takes by
behavioral harassment only).
(4) A reduction in the intensity of exposure to stimuli expected to
result in incidental take (this goal may contribute to 1, above, or to
reducing the severity of behavioral harassment only).
(5) Avoidance or minimization of adverse effects to marine mammal
habitat, paying particular attention to the prey base, blockage or
limitation of passage to or from biologically important areas,
permanent destruction of habitat, or temporary disturbance of habitat
during a biologically important time.
(6) For monitoring directly related to mitigation, an increase in
the probability of detecting marine mammals, thus allowing for more
effective implementation of the mitigation.
Based on our evaluation of the Navy's proposed measures, as well as
any other potential measures that may be relevant to the specified
activity, we have preliminarily determined that the proposed mitigation
measures provide the means of effecting the least practicable impact on
marine mammal species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must 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
incidental take authorizations must include the suggested means of
accomplishing the necessary monitoring and reporting that will 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.
Any monitoring requirement we prescribe should improve our
understanding of one or more of the following:
Occurrence of marine mammal species in action area (e.g.,
presence, abundance, distribution, density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
Affected species (e.g., life history, dive patterns); (3) Co-occurrence
of marine mammal species with the action; or (4) Biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual responses to acute stressors, or impacts of
chronic exposures (behavioral or physiological).
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of an individual; or (2) Population,
species, or stock.
Effects on marine mammal habitat and resultant impacts to
marine mammals.
Mitigation and monitoring effectiveness.
The Navy's proposed monitoring and reporting is also described in
their Marine Mammal Monitoring Plan, on the Internet at
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.
Visual Marine Mammal Observations
The Navy will collect sighting data and behavioral responses to
construction for marine mammal species observed in the region of
activity during the period of activity. All observers (MMOs) will be
trained in marine mammal identification and behaviors and are required
to have no other construction-related tasks while conducting
monitoring. The Navy will monitor the shutdown zone and disturbance
zone before, during, and after pile driving, with observers located at
the best practicable vantage points. Based on our requirements, the
Navy would implement the following procedures for pile driving:
MMOs would be located at the best vantage point(s) in
order to properly see the entire shutdown zone and as much of the
disturbance zone as possible.
During all observation periods, observers will use
binoculars and the naked eye to search continuously for marine mammals.
If the shutdown zones are obscured by fog or poor lighting
conditions, pile driving at that location will not be initiated until
that zone is visible. Should such conditions arise while impact driving
is underway, the activity would be halted.
The shutdown and disturbance zones around the pile will be
monitored for the presence of marine mammals before, during, and after
any pile driving or removal activity.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. The monitoring biologists
will use their best professional judgment throughout implementation and
seek improvements to these methods when deemed appropriate. Any
modifications to protocol will be coordinated between NMFS and the
Navy.
Data Collection
We require that observers use approved data forms. Among other
pieces of information, the Navy will record detailed information about
any implementation of shutdowns, including the distance of animals to
the pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, the Navy will attempt to
distinguish between the number of individual animals taken and the
number of incidences of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel, and if possible,
the correlation to SPLs;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Description of implementation of mitigation measures
(e.g., shutdown or delay);
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report would be submitted to NMFS within 90 days of the
completion
[[Page 75991]]
of marine mammal monitoring, or sixty days prior to the requested date
of issuance of any future IHA for projects at the same location,
whichever comes first. The report will include marine mammal
observations pre-activity, during-activity, and post-activity during
pile driving days, and will also provide descriptions of any behavioral
responses to construction activities by marine mammals and a complete
description of all mitigation shutdowns and the results of those
actions and an extrapolated total take estimate based on the number of
marine mammals observed during the course of construction. A final
report must be submitted within thirty days following resolution of
comments on the draft report.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here,
section 3(18) of 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].''
All anticipated takes would be by Level B harassment resulting from
vibratory and impact pile driving and involving temporary changes in
behavior. The proposed mitigation and monitoring measures are expected
to minimize the possibility of injurious or lethal takes such that take
by Level A harassment, serious injury, or mortality is considered
discountable. However, it is unlikely that injurious or lethal takes
would occur even in the absence of the planned mitigation and
monitoring measures.
If a marine mammal responds to a stimulus by changing its behavior
(e.g., through relatively minor changes in locomotion direction/speed
or vocalization behavior), the response may or may not constitute
taking at the individual level, and is unlikely to affect 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 animals or on the stock or species could potentially
be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007). Given
the many uncertainties in predicting the quantity and types of impacts
of sound on marine mammals, it is common practice to estimate how many
animals are likely to be present within a particular distance of a
given activity, or exposed to a particular level of sound. In practice,
depending on the amount of information available to characterize daily
and seasonal movement and distribution of affected marine mammals, it
can be difficult to distinguish between the number of individuals
harassed and the instances of harassment and, when duration of the
activity is considered, it can result in a take estimate that
overestimates the number of individuals harassed. In particular, for
stationary activities, it is more likely that some smaller number of
individuals may accrue a number of incidences of harassment per
individual than for each incidence to accrue to a new individual,
especially if those individuals display some degree of residency or
site fidelity and the impetus to use the site (e.g., because of
foraging opportunities) is stronger than the deterrence presented by
the harassing activity.
The turning basin is not considered important habitat for marine
mammals, as it is a man-made, semi-enclosed basin with frequent
industrial activity and regular maintenance dredging. The surrounding
waters may be an important foraging habitat for the dolphins; however
the small area of ensonification does not extend outside of the turning
basin and into this foraging habitat (see Figure 6-1 in the Navy's
application). Therefore, behavioral disturbances that could result from
anthropogenic sound associated with these activities are expected to
affect only a relatively small number of individual marine mammals that
may venture near the turning basin, although those effects could be
recurring over the life of the project if the same individuals remain
in the project vicinity. The Navy has requested authorization for the
incidental taking of small numbers of bottlenose dolphins in the
Mayport turning basin that may result from pile driving during
construction activities associated with the project described
previously in this document.
In order to estimate the potential incidents of take that may occur
incidental to the specified activity, we must first estimate the extent
of the sound field that may be produced by the activity and then
consider in combination with information about marine mammal density or
abundance in the project area. We first provide information on
applicable sound thresholds for determining effects to marine mammals
before describing the information used in estimating the sound fields,
the available marine mammal density or abundance information, and the
method of estimating potential incidents of take.
Sound Thresholds
We use generic sound exposure thresholds to determine when an
activity that produces sound might result in impacts to a marine mammal
such that a take by harassment might occur. To date, no studies have
been conducted that explicitly examine impacts to marine mammals from
pile driving sounds or from which empirical sound thresholds have been
established. These thresholds (Table 2) are used to estimate when
harassment may occur (i.e., when an animal is exposed to levels equal
to or exceeding the relevant criterion) in specific contexts; however,
useful contextual information that may inform our assessment of effects
is typically lacking and we consider these thresholds as step
functions. NMFS is working to revise these acoustic guidelines; for
more information on that process, please visit www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
Table 2--Current Acoustic Exposure Criteria
------------------------------------------------------------------------
Criterion Definition Threshold
------------------------------------------------------------------------
Level A harassment Injury (PTS--any 180 dB (cetaceans)/
(underwater). level above that 190 dB (pinnipeds)
which is known (rms).
to cause TTS).
Level B harassment Behavioral 160 dB (impulsive
(underwater). disruption. source)/120 dB
(continuous source)
(rms).
Level B harassment (airborne). Behavioral 90 dB (harbor seals)/
disruption. 100 dB (other
pinnipeds)
(unweighted).
------------------------------------------------------------------------
[[Page 75992]]
Distance to Sound Thresholds
Underwater Sound Propagation Formula--Pile driving generates
underwater noise that can potentially result in disturbance to marine
mammals in the project area. Transmission loss (TL) is the decrease in
acoustic intensity as an acoustic pressure wave propagates out from a
source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and
bottom composition and topography. The general formula for underwater
TL is:
TL = B * log10(R1/R2),
Where:
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of fifteen is often used under conditions,
such as at the NSM turning basin, where water increases with depth as
the receiver moves away from the shoreline, resulting in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions. Practical spreading loss (4.5 dB
reduction in sound level for each doubling of distance) is assumed
here.
Underwater Sound--The intensity of pile driving sounds is greatly
influenced by factors such as the type of piles, hammers, and the
physical environment in which the activity takes place. A number of
studies, primarily on the west coast, have measured sound produced
during underwater pile driving projects. However, these data are
largely for impact driving of steel pipe piles and concrete piles as
well as vibratory driving of steel pipe piles. Vibratory driving of
steel sheet piles was monitored during the first year of construction
at the nearby Wharf C-2 at Naval Station Mayport during 2015.
Measurements were conducted from a small boat in the turning basin and
from the construction barge itself. Details are available in DoN
(2015). Source levels averaged 151 dB re 1 [mu]Pa rms (DoN, 2015). No
impact driving was measured at this location; therefore, proxy levels
for impact driving have been calculated from other available source
levels.
In order to determine reasonable SPLs and their associated effects
on marine mammals that are likely to result from impact pile driving at
NSM, we considered existing measurements from similar physical
environments (sandy sediments and water depths greater than 15 ft) for
impact and vibratory driving of 24-in steel pipe piles and for steel
sheet piles. These studies, largely conducted by the Washington State
Department of Transportation and the California Department of
Transportation, show typical values around 160 dB for vibratory driving
of 24-in pipe piles and sheet piles, and around 185-195 dB for impact
driving of similar pipe piles (all measured at 10 m; e.g., Laughlin,
2005a, 2005b; Illingworth and Rodkin, 2010, 2012, 2013; CalTrans,
2012). For impact driving of sheet piles a proxy source value of 189 dB
(CalTrans, 2012) was selected for use in acoustic modeling based on
similarity to the physical environment at NSM and because of the
measurement location in mid-water column. All calculated distances to
and the total area encompassed by the marine mammal sound thresholds
are provided in Table 3.
Table 3--Distances to Relevant Underwater Sound Thresholds and Areas of Ensonification
----------------------------------------------------------------------------------------------------------------
Distance Area (sq
Pile type Method Threshold (m) \1\ km\2\)
----------------------------------------------------------------------------------------------------------------
Steel sheet piles.................. Vibratory............ Level A harassment (180 0 0
dB). 1,166 0.614439
Level B harassment (120
dB).
Impact............... Level A harassment (180 40 0.002
dB). 858 0.51
Level B harassment (160
dB).
----------------------------------------------------------------------------------------------------------------
\1\ Areas presented take into account attenuation and/or shadowing by land. Calculated distances to relevant
thresholds cannot be reached in most directions form source piles. Please see Figures 6-1 and 6-2 in the
Navy's application.
The Mayport turning basin does not represent open water, or free
field, conditions. Therefore, sounds would attenuate as per the
confines of the basin, and may only reach the full estimated distances
to the harassment thresholds via the narrow, east-facing entrance
channel. Distances shown in Table 3 are estimated for free-field
conditions, but areas are calculated per the actual conditions of the
action area. See Figures 6-1 and 6-2 of the Navy's application for a
depiction of areas in which each underwater sound threshold is
predicted to occur at the project area due to pile driving.
Marine Mammal Densities
For all species, the best scientific information available was
considered for use in the marine mammal take assessment calculations.
Density for bottlenose dolphins is derived from site-specific surveys
conducted by the Navy (see Appendix C of the Navy's application for
more information); it is not currently possible to identify observed
individuals to stock. This survey effort consists of 24 half-day
observation periods covering mornings and afternoons during four
seasons (December 10-13, 2012, March 4-7, 2013, June 3-6, 2013, and
September 9-12, 2013). During each observation period, two observers (a
primary observer at an elevated observation point and a secondary
observer at ground level) monitored for the presence of marine mammals
in the turning basin (0.712 km\2\) and an additional grid east of the
basin entrance. Observers tracked marine mammal movements and behavior
within the observation area, with observations recorded for five-minute
intervals every half-hour. Morning sessions typically ran from 7:00-
11:30 and afternoon sessions from 1:00 to 5:30.
Most observations of bottlenose dolphins were of individuals or
pairs, although larger groups were
[[Page 75993]]
occasionally observed (median number of dolphins observed ranged from
1-3.5 across seasons). Densities were calculated using observational
data from the primary observer supplemented with data from the
secondary observer for grids not visible by the primary observer.
Season-specific density was then adjusted by applying a correction
factor for observer error (i.e., perception bias). The seasonal
densities range from 1.98603 (winter) to 4.15366 (summer) dolphins/
km\2\. We conservatively use the largest density value to assess take,
as the Navy does not have specific information about when in-water work
may occur during the proposed period of validity.
Description of Take Calculation
The following assumptions are made when estimating potential
incidents of take:
All marine mammal individuals potentially available are
assumed to be present within the relevant area, and thus incidentally
taken;
An individual can only be taken once during a 24-h period;
and,
There will be 110 total days of vibratory driving (seventy
three days in phase I and thirty seven days in phase II) and twenty
days of impact pile driving.
Exposures to sound levels at or above the relevant
thresholds equate to take, as defined by the MMPA.
The estimation of marine mammal takes typically uses the following
calculation:
Exposure estimate = (n * ZOI) * days of total activity
Where:
n = density estimate used for each species/season
ZOI = sound threshold ZOI area; the area encompassed by all
locations where the SPLs equal or exceed the threshold being
evaluated
n * ZOI produces an estimate of the abundance of animals that could
be present in the area for exposure, and is rounded to the nearest
whole number before multiplying by days of total activity.
The ZOI impact area is estimated using the relevant distances in
Table 3, taking into consideration the possible affected area with
attenuation due to the constraints of the basin. Because the basin
restricts sound from propagating outward, with the exception of the
east-facing entrance channel, the radial distances to thresholds are
not generally reached.
There are a number of reasons why estimates of potential incidents
of take may be conservative, assuming that available density or
abundance estimates and estimated ZOI areas are accurate. We assume, in
the absence of information supporting a more refined conclusion, that
the output of the calculation represents the number of individuals that
may be taken by the specified activity. In fact, in the context of
stationary activities such as pile driving and in areas where resident
animals may be present, this number more realistically represents the
number of incidents of take that may accrue to a smaller number of
individuals. While pile driving can occur any day throughout the in-
water work window, and the analysis is conducted on a per day basis,
only a fraction of that time (typically a matter of hours on any given
day) is actually spent pile driving. The potential effectiveness of
mitigation measures in reducing the number of takes is typically not
quantified in the take estimation process. For these reasons, these
take estimates may be conservative.
The quantitative exercise described above indicates that no
incidents of Level A harassment would be expected, independent of the
implementation of required mitigation measures. See Table 4 for total
estimated incidents of take.
Table 4--Calculations for Incidental Take Estimation
----------------------------------------------------------------------------------------------------------------
n (animals/ Proposed authorized
Species km\2\) Activity n * ZOI \1\ takes \2\
----------------------------------------------------------------------------------------------------------------
Phase I (73 days)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin \3\........... 4.15366 Vibratory driving... 3 219
----------------------------------------------------------------------------------------------------------------
Phase II (37 days)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin \3\........... 4.15366 Vibratory driving... 3 111
----------------------------------------------------------------------------------------------------------------
Contingency impact driving (20 days)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin \3\........... 4.15366 Impact driving...... 1 40
----------------------
Total exposures.............. ................ .................... .............. 370
----------------------------------------------------------------------------------------------------------------
\1\ See Table 3 for relevant ZOIs. The product of this calculation is rounded to the nearest whole number.
\2\ The product of n * ZOI is multiplied by the total number of activity-specific days to estimate the number of
takes.
\3\ It is impossible to estimate from available information which stock these takes may accrue to.
Analyses and Preliminary Determinations
Negligible Impact Analysis
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.'' A negligible impact finding is based on the
lack of likely adverse effects on annual rates of recruitment or
survival (i.e., population-level effects). An estimate of the number of
Level B harassment takes alone is not enough information on which to
base an impact determination. In addition to considering estimates of
the number of marine mammals that might be ``taken'' through behavioral
harassment, we consider other factors, such as the likely nature of any
responses (e.g., intensity, duration), the context of any responses
(e.g., critical reproductive time or location, migration), as well as
the number and nature of estimated Level A harassment takes, the number
of estimated mortalities, and effects on habitat.
Pile driving activities associated with the wharf construction
project, as outlined previously, have the potential to disturb or
displace marine mammals. Specifically, the specified activities may
result in take, in the form of Level B harassment (behavioral
disturbance) only, from underwater sounds generated
[[Page 75994]]
from pile driving. Potential takes could occur if individuals of these
species are present in the ensonified zone when pile driving is
happening.
No injury, serious injury, or mortality is anticipated given the
nature of the activities and measures designed to minimize the
possibility of injury to marine mammals. The potential for these
outcomes is minimized through the construction method and the
implementation of the planned mitigation measures. Specifically,
vibratory hammers will be the primary method of installation (impact
driving is included only as a contingency and is not expected to be
required), and this activity does not have the potential to cause
injury to marine mammals due to the relatively low source levels
produced (less than 180 dB) and the lack of potentially injurious
source characteristics. Impact pile driving produces short, sharp
pulses with higher peak levels and much sharper rise time to reach
those peaks. If impact driving is necessary, implementation of soft
start and shutdown zones significantly reduces any possibility of
injury. Given sufficient ``notice'' through use of soft start (for
impact driving), marine mammals are expected to move away from a sound
source that is annoying prior to it becoming potentially injurious.
Environmental conditions in the confined and protected Mayport turning
basin mean that marine mammal detection ability by trained observers is
high, enabling a high rate of success in implementation of shutdowns to
avoid injury.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff,
2006; HDR, Inc., 2012). Most likely, individuals will simply move away
from the sound source and be temporarily displaced from the areas of
pile driving, although even this reaction has been observed primarily
only in association with impact pile driving. The pile driving
activities analyzed here are similar to, or less impactful than,
numerous other construction activities conducted in San Francisco Bay
and in the Puget Sound region, which have taken place with no reported
injuries or mortality to marine mammals, and no known long-term adverse
consequences from behavioral harassment. These activities are also
nearly identical to the pile driving activities that took place at
Wharf C-2 at NSM, which also reported zero injuries or mortality to
marine mammals and no known long-term adverse consequences from
behavioral harassment. Repeated exposures of individuals to levels of
sound that may cause Level B harassment are unlikely to result in
hearing impairment or to significantly disrupt foraging behavior. Thus,
even repeated Level B harassment of some small subset of the overall
stock is unlikely to result in any significant realized decrease in
viability for the affected individuals, and thus would not result in
any adverse impact to the stock as a whole. Level B harassment will be
reduced to the level of least practicable impact through use of
mitigation measures described herein and, if sound produced by project
activities is sufficiently disturbing, animals are likely to simply
avoid the turning basin while the activity is occurring.
In summary, this negligible impact analysis is founded on the
following factors: (1) The possibility of injury, serious injury, or
mortality may reasonably be considered discountable; (2) the
anticipated incidents of Level B harassment consist of, at worst,
temporary modifications in behavior; (3) the absence of any significant
habitat within the project area, including known areas or features of
special significance for foraging or reproduction; (4) the presumed
efficacy of the proposed mitigation measures in reducing the effects of
the specified activity to the level of least practicable impact. In
addition, these stocks are not listed under the ESA, although coastal
bottlenose dolphins are designated as depleted under the MMPA. In
combination, we believe that these factors, as well as the available
body of evidence from other similar activities, demonstrate that the
potential effects of the specified activity will have only short-term
effects on individuals. The specified activity is not expected to
impact rates of recruitment or survival and will therefore not result
in population-level impacts.
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 proposed monitoring and
mitigation measures, we preliminarily find that the total marine mammal
take from the Navy's wharf construction activities will have a
negligible impact on the affected marine mammal species or stocks.
Small Numbers Analysis
As described previously, of the 370 incidents of behavioral
harassment predicted to occur for bottlenose dolphin, we have no
information allowing us to parse those predicted incidents amongst the
three stocks of bottlenose dolphin that may occur in the project area.
Therefore, we assessed the total number of predicted incidents of take
against the best abundance estimate for each stock, as though the total
would occur for the stock in question. For one of the bottlenose
dolphin stocks, the total predicted number of incidents of take
authorized would be considered small--approximately four percent for
the southern migratory stock- even if each estimated taking occurred to
a new individual. This is an extremely unlikely scenario as, for
bottlenose dolphins in estuarine and nearshore waters, there is likely
to be some overlap in individuals present day-to-day.
The total number of authorized takes proposed for bottlenose
dolphins, if assumed to accrue solely to new individuals of the JES or
northern Florida coastal stocks, is higher relative to the total stock
abundance, which is currently considered unknown for the JES stock and
is 1,219 for the northern Florida coastal stock. However, these numbers
represent the estimated incidents of take, not the number of
individuals taken. That is, it is highly likely that a relatively small
subset of these bottlenose dolphins would be harassed by project
activities.
JES bottlenose dolphins range from Cumberland Sound at the Georgia-
Florida border south to approximately Palm Coast, Florida, an area
spanning over 120 linear km of coastline and including habitat
consisting of complex inshore and estuarine waterways. JES dolphins,
divided by Caldwell (2001) into Northern and Southern groups, show
strong site fidelity and, although members of both groups have been
observed outside their preferred areas, it is likely that the majority
of JES dolphins would not occur within waters ensonified by project
activities.
In the western North Atlantic, the Northern Florida Coastal Stock
is present in coastal Atlantic waters from the Georgia/Florida border
south to 29.4[deg] N. (Waring et al., 2014), a span of more than 90
miles. There is no obvious boundary defining the offshore extent of
this stock. They occur in waters less than 20 m deep; however, they may
also occur in lower densities over the continental shelf (waters
between 20 m and 100 m depth) and overlap spatially with the offshore
morphotype (Waring et al., 2014).
In summary, JES dolphins are known to form two groups and exhibit
strong site fidelity (i.e., individuals do not
[[Page 75995]]
generally range throughout the recognized overall JES stock range); and
neither stock is expected to occur at all in a significant portion of
the larger ZOI, which is almost entirely confined within NSM. Given
that the specified activity will be stationary within an enclosed basin
not recognized as an area of any special significance that would serve
to attract or aggregate dolphins, we therefore believe that the
estimated numbers of takes, were they to occur, likely represent
repeated exposures of a much smaller number of bottlenose dolphins and
that these estimated incidents of take represent small numbers of
bottlenose 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, we preliminarily find that small numbers of marine mammals
will be taken relative to the populations of the affected species or
stocks.
Impact on Availability of Affected Species for Taking for Subsistence
Uses
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, we have determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
No marine mammal species listed under the ESA are expected to be
affected by these activities. Therefore, we have determined that
section 7 consultation under the ESA is not required.
National Environmental Policy Act (NEPA)
The Navy has prepared a Draft Environmental Assessment (EA;
Environmental Assessment for the Wharf Bravo Recapitalization at Naval
Station Mayport, Jacksonville, FL) in accordance with NEPA and the
regulations published by the Council on Environmental Quality. We have
posted it on the NMFS Web site (see SUPPLEMENTARY INFORMATION)
concurrently with the publication of this proposed IHA. NMFS will
independently evaluate the EA and determine whether or not to adopt it.
We may prepare a separate NEPA analysis and incorporate relevant
portions of the Navy's EA by reference. Information in the Navy's
application, EA, and this notice collectively provide the environmental
information related to proposed issuance of the IHA for public review
and comment. We will review all comments submitted in response to this
notice as we complete the NEPA process, including a decision of whether
to sign a Finding of No Significant Impact (FONSI), prior to a final
decision on the IHA request. The 2015 NEPA documents are available for
review at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.
Proposed Authorization
As a result of these preliminary determinations, we propose to
authorize the take of marine mammals incidental to the Navy's Bravo
wharf recapitalization project, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
Specific language from the proposed IHA is provided next.
This section contains a draft of the IHA. The wording contained in
this section is proposed for inclusion in the IHA (if issued).
1. This Incidental Harassment Authorization (IHA) is valid for one
year from the date of issuance.
2. This IHA is valid only for pile driving activities associated
with the Bravo Wharf Recapitalization Project at Naval Station Mayport,
Florida.
3. General Conditions
(a) A copy of this IHA must be in the possession of the Navy, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species authorized for taking is the bottlenose dolphin
(Tursiops truncatus).
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b). See Table 1 for numbers of take
authorized.
Table 1--Authorized Take Numbers
----------------------------------------------------------------------------------------------------------------
Authorized take
----------------------------------------------------
Species Contingency
Phase I Phase II impact driving
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin......................................... 219 111 40
----------------------------------------------------------------------------------------------------------------
(d) The taking by injury (Level A harassment), serious injury, or
death of the species listed in condition 3(b) of the Authorization or
any taking of any other species of marine mammal is prohibited and may
result in the modification, suspension, or revocation of this IHA.
(e) The Navy shall conduct briefings between construction
supervisors and crews, marine mammal monitoring team, and Navy staff
prior to the start of all pile driving activity, and when new personnel
join the work, in order to explain responsibilities, communication
procedures, marine mammal monitoring protocol, and operational
procedures.
4. Mitigation Measures
The holder of this Authorization is required to implement the
following mitigation measures:
(a) For all pile driving, the Navy shall implement a minimum
shutdown zone of 15 m radius around the pile. If a marine mammal comes
within or approaches the shutdown zone, such operations shall cease.
For impact driving of steel piles, the minimum shutdown zone shall be
of 40 m radius.
(b) The Navy shall establish monitoring locations as described
below. Please also refer to the Marine Mammal Monitoring Plan (see
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm).
i. For all pile driving activities, a minimum of two observers
shall be deployed, with one positioned to achieve optimal monitoring of
the shutdown zone and the second positioned to achieve optimal
monitoring of surrounding waters of the turning basin, the entrance to
that basin, and portions of the Atlantic Ocean. If practicable, the
second observer should be deployed to an elevated position, preferably
opposite Bravo Wharf and with clear sight lines to the wharf and out
the entrance channel.
ii. These observers shall record all observations of marine
mammals, regardless of distance from the pile being driven, as well as
behavior and potential behavioral reactions of the animals.
Observations within the turning basin shall be distinguished from those
in the entrance channel and nearshore waters of the Atlantic Ocean.
[[Page 75996]]
iii. All observers shall be equipped for communication of marine
mammal observations amongst themselves and to other relevant personnel
(e.g., those necessary to effect activity delay or shutdown).
(c) Monitoring shall take place from fifteen minutes prior to
initiation of pile driving activity through thirty minutes post-
completion of pile driving activity. Pre-activity monitoring shall be
conducted for fifteen minutes to ensure that the shutdown zone is clear
of marine mammals, and pile driving may commence when observers have
declared the shutdown zone clear of marine mammals. In the event of a
delay or shutdown of activity resulting from marine mammals in the
shutdown zone, animals shall be allowed to remain in the shutdown zone
(i.e., must leave of their own volition) and their behavior shall be
monitored and documented. Monitoring shall occur throughout the time
required to drive a pile. The shutdown zone must be determined to be
clear during periods of good visibility (i.e., the entire shutdown zone
and surrounding waters must be visible to the naked eye).
(d) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted. If pile
driving is halted or delayed due to the presence of a marine mammal,
the activity may not commence or resume until either the animal has
voluntarily left and been visually confirmed beyond the shutdown zone
or fifteen minutes have passed without re-detection of the animal.
(e) Monitoring shall be conducted by qualified observers, as
described in the Monitoring Plan. Trained observers shall be placed
from the best vantage point(s) practicable to monitor for marine
mammals and implement shutdown or delay procedures when applicable
through communication with the equipment operator. Observer training
must be provided prior to project start and in accordance with the
monitoring plan, and shall include instruction on species
identification (sufficient to distinguish the species listed in 3(b)),
description and categorization of observed behaviors and interpretation
of behaviors that may be construed as being reactions to the specified
activity, proper completion of data forms, and other basic components
of biological monitoring, including tracking of observed animals or
groups of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
(f) The Navy shall use soft start techniques recommended by NMFS
for impact pile driving. Soft start requires contractors to provide an
initial set of strikes at reduced energy, followed by a thirty-second
waiting period, then two subsequent reduced energy strike sets. Soft
start shall be implemented at the start of each day's impact pile
driving and at any time following cessation of impact pile driving for
a period of thirty minutes or longer.
(g) Pile driving shall only be conducted during daylight hours.
5. Monitoring
The holder of this Authorization is required to conduct marine
mammal monitoring during pile driving activity. Marine mammal
monitoring and reporting shall be conducted in accordance with the
Monitoring Plan.
(a) The Navy shall collect sighting data and behavioral responses
to pile driving for marine mammal species observed in the region of
activity during the period of activity. All observers shall be trained
in marine mammal identification and behaviors, and shall have no other
construction-related tasks while conducting monitoring.
(b) For all marine mammal monitoring, the information shall be
recorded as described in the Monitoring Plan.
6. Reporting
The holder of this Authorization is required to:
(a) Submit a draft report on all monitoring conducted under the IHA
within ninety days of the completion of marine mammal monitoring, or
sixty days prior to the issuance of any subsequent IHA for projects at
NSM, whichever comes first. A final report shall be prepared and
submitted within thirty days following resolution of comments on the
draft report from NMFS. This report must contain the informational
elements described in the Monitoring Plan, at minimum (see
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), and shall
also include:
i. Detailed information about any implementation of shutdowns,
including the distance of animals to the pile and description of
specific actions that ensued and resulting behavior of the animal, if
any.
ii. Description of attempts to distinguish between the number of
individual animals taken and the number of incidents of take, such as
ability to track groups or individuals.
iii. An estimated total take estimate extrapolated from the number
of marine mammals observed during the course of construction
activities, if necessary.
(b) 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 this IHA,
such as an injury (Level A harassment), serious injury, or mortality,
Navy shall immediately cease the specified activities and report the
incident to the 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 Navy to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. Navy may not resume
their activities until notified by NMFS.
ii. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer 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), Navy shall immediately report
the incident to the Office of Protected Resources, NMFS, and the
Southeast Regional Stranding Coordinator, NMFS.
The report must include the same information identified in 6(b)(i)
of this IHA. Activities may continue while NMFS reviews the
circumstances of the incident. NMFS will work with Navy to determine
whether additional mitigation measures or modifications to the
activities are appropriate.
iii. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, scavenger damage), Navy shall report the incident to the
Office of Protected Resources, NMFS, and the Southeast Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. Navy
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS.
[[Page 75997]]
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
NMFS determines the authorized taking is having more than a negligible
impact on the species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analyses, the draft authorization, and
any other aspect of this Notice of Proposed IHAs for Navy's wharf
construction activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on Navy's request for an MMPA authorization.
Dated: December 2, 2015.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2015-30745 Filed 12-4-15; 8:45 am]
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