Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Confined Blasting Operations in the East Channel by the U.S. Army Corps of Engineers During the Tampa Harbor Big Bend Channel Expansion Project in Tampa Harbor, Tampa, Florida, 11968-11989 [2018-05504]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 53 (Monday, March 19, 2018)]
[Notices]
[Pages 11968-11989]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-05504]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF800


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Confined Blasting Operations in the 
East Channel by the U.S. Army Corps of Engineers During the Tampa 
Harbor Big Bend Channel Expansion Project in Tampa Harbor, Tampa, 
Florida

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. Army Corps of 
Engineers, Jacksonville District, (USACE) for authorization to take 
marine mammals incidental to confined blasting in the East Channel of 
the Big Bend Channel in Tampa Harbor, Tampa, Florida. Pursuant to the 
Marine Mammal Protection Act (MMPA), NMFS is

[[Page 11969]]

requesting comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS will consider public comments prior to 
making any final decision on the issuance of the requested MMPA 
authorizations and agency responses will be summarized in the final 
notice of our decision.

DATES: Comments and information must be received no later than April 
18, 2018.

ADDRESSES: Comments 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 online at 
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities 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: Dale Youngkin, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, 
please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (as delegated to NMFS) to allow, upon 
request, the incidental, but not intentional, taking of small numbers 
of marine mammals by U.S. citizens who engage in a specified activity 
(other than commercial fishing) within a specified geographical region 
if certain findings are made and either regulations are issued or, if 
the taking is limited to harassment, a notice of a proposed 
authorization is provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as an 
impact resulting from the specified activity that cannot be reasonably 
expected to, and is not reasonably likely to, adversely affect the 
species or stock through effects on annual rates of recruitment or 
survival.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill or attempt to harass, hunt, capture, or kill any marine 
mammal. 16 U.S.C. 1362(13).
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild (Level A harassment); or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (Level B harassment). 16 U.S.C. 1362(18)(A).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    Accordingly, NMFS plans to adopt the USACE's Supplemental 
Environmental Assessment (EA) (August, 2017), provided our independent 
evaluation of the document finds that it includes adequate information 
analyzing the effects on the human environment of issuing the IHA. The 
USACE's Supplemental EA and Finding of No Significant Impact (FONSI) is 
available at https://www.saj.usace.army.mil/About/DivisionsOffices/Planning/EnvironmentalBranch/EnvironmentalDocuments.aspx#Hillsborough, 
and is also available for review on our website at https://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On August 8, 2017, NMFS received a request from USACE for an IHA to 
take marine mammals incidental to confined blasting within the East 
Channel of the Tampa Harbor Big Bend Channel Expansion Project in 
Tampa, Florida. USACE's request is for take of a small number of the 
Tampa Bay stock of bottlenose dolphins (Tursiops truncatus) by Level B 
harassment only. Neither USACE nor NMFS expect mortality to result from 
this activity and, therefore, an IHA is appropriate.
    NMFS previously issued an IHA to USACE for similar work in the 
Miami Harbor (77 FR 49278, August 15, 2012). However, ultimately, USACE 
did not perform any confined blasting under that IHA. Prior to that, 
NMFS issued an IHA to the USACE for similar work in the Miami Harbor 
Phase II Project in 2005 (70 FR 21174, April 25, 2005) and 2003 (68 FR 
32016, May 29, 2003).

Description of Proposed Activity

Overview

    The proposed Tampa Harbor Big Bend Channel Expansion Project is 
located within Hillsborough Bay (part of Tampa Bay), Hillsborough 
County, Florida. The five major features of the entire project include 
the following (refer to Figure 2 of the application), but only confined 
underwater blasting associated with Feature 5 is covered in USACE's IHA 
application.
     Feature 1 of the project will deepen the project depths of 
the existing Entrance Channel, Turning Basin, East Channel and Inner 
Channel from 10.36 meters (m) (34 feet (ft)) to 14 m (46 ft).
     Feature 2 of the project will widen the north side of the 
Entrance Channel by 15.2 m (50 ft), from 61 m (200 ft) to 76.2 m (250 
ft) and deepen it from 10.36 m (34 feet) to 14 m (46 feet).
     Feature 3 of the project will widen the Turning Basin 
approximately 57.9 m(190 ft) to the southwest to provide a 365.8 m 
(1,200 ft) turning radius and deepen it from 10.36 m (34 ft) to 14 m 
(46 ft).
     Feature 4 of the project will add a widener at the 
southeast corner of the intersection of the Turning Basin and East 
Channel and deepen it from 10.36 m (34 ft) to 14 m (46 ft).

[[Page 11970]]

     Feature 5 of the project will deepen local service 
facilities (non- federal berthing areas) located north, south, and east 
of the East Channel and at the south end of the Inner Channel from 
10.36 m (34 ft) to 14 m (46 ft).
    The USACE IHA application is for work associated with Feature 5 of 
the project, and would involve possible use of confined underwater 
blasting (placement of an explosive charge into pre-drilled holes 
approximately 1.5-3 m deep and capping the hole with inert materials 
such as crushed rock in order to break up rock substrate along the 
bottom) to deepen the project's East Channel. To deepen the Big Bend 
Channel portion of the Tampa Harbor Federal Navigation Project from 
10.36 m (34 ft) to 14 m (46 ft), confined underwater blasting may be 
necessary to pretreat rock areas within the East Channel, where 
dredging or other rock removal methods are unsuccessful due to the 
hardness and massiveness of the rock. Sound and pressure associated 
with this underwater blasting has the potential to incidentally take 
marine mammals. The existing East Channel is a man-made channel with a 
history of maintenance dredging and is approximately 1,450 m (4,757 ft) 
long and 185 m (607 ft) wide at its widest location. Confined 
underwater blasting is not proposed within the Entrance Channel, 
Turning Basin, or Inner Channel, or any project area other than the 
East Channel.

Dates and Duration

    Once a contractor has been selected, a specific blasting plan will 
be prepared that will specify the charge weights and blasting patterns 
to be used. However, in accordance with the USACE's Endangered Species 
Act Section 7 consultation with the U.S. Fish and Wildlife Service 
(USFWS), confined underwater blasting operations or rock pre-treatment 
will only be conducted during the months of April through October 
(tentatively scheduled April 1, 2019 through September 30, 2019) in 
order to avoid take of the West Indian Manatee (Trichecus manatus). The 
exact duration of blasting will be dependent upon a number of factors 
including hardness of rock, how close the drill holes are placed in 
relation to each other, and the type of dredging equipment that will be 
used to remove the pretreated rock. However, certain restrictions shall 
be imposed on all blasting operations.
    In addition to the blasting window being limited to occur from 
April through October, the contractor shall not exceed a total of 42 
blast events. A blast event may include the detonation of a blast 
pattern with up to 40 individual charges. If multiple blast events are 
performed in one day, then the blast events shall be separated by an 
estimated minimum six hours. When blasting operations are conducted, 
they will take place 24-hours a day, typically six days a week. The 
contractor may drill the blast pattern at night and then blast after at 
least two hours after sunrise (one hour plus one hour of monitoring). 
After detonation of the first pattern, a second pattern may be drilled 
and detonated under the following circumstances: (1) It is not less 
than one hour before sunset, and (2) at least six hours have passed 
since the previous detonation. Blasting activities normally will not 
take place on Sundays due to local ordinances.

Specific Geographic Region

    The proposed confined underwater blasting activities would be 
performed only within the East Channel of the Tampa Harbor Big Bend 
Channel Expansion Project located within Hillsborough Bay (part of 
Tampa Bay), Hillsborough County, Florida (refer to Figures 1 and 2 of 
the application). Coordinates for the approximate center of the East 
Channel are 27[deg]48'25.93'' N and 82[deg]24'24.21'' W.

Detailed Description of Specific Activity

    The East Channel of Tampa Harbor Big Bend Channel will be deepened 
by pre-treating the limestone foundation along the bottom of the 
Channel utilizing confined blasting (the shots will be ``confined'' 
within the rock), and after blasting the material will be removed by 
dredge. As described above, explosive charges will be placed within 
holes drilled into the limestone. Blast holes will be small in 
diameter, typically 5-10 centimeters (cm) (2-4 inches (in)), and 1.5-3 
m (5-10 ft) deep. Drilling activities will take place for a short 
duration, with no more than three holes being drilled at the same time. 
Due to the equipment used and the short duration of the drilling 
activity, drilling is not anticipated to have the potential to result 
in take of marine mammals.
    Typically, each blast pattern is set up in a square or rectangular 
area divided into rows and columns, although some blast patterns may 
consist of a single line (for use near bulkheads, for example). The 
proposed project will use a maximum of 40 charges per pattern. In 
confined blasting, each charge is placed in a pre-drilled hole and the 
hole is then capped with an inert material (known as ``stemming the 
hole''). Studies have shown that stemmed blasts have up to a 60-90 
percent decrease in the strength of the pressure released compared to 
open water blasts of the same charge weight (Nedwell and 
Thandavamoorthy, 1992; Hempen et al., 2005; Hempen et al., 2007). 
However, unlike open water blasts, very little peer-reviewed research 
exists on the effects on marine animals near a stemmed blast.
    A delay is defined as a distinct pause of predetermined time 
between detonation or initiation impulses to permit the firing of 
explosive charges separately. Delay blasting is the practice of 
initiating individual explosive decks, boreholes, or rows of boreholes 
at predetermined time intervals using delay detonators, as compared to 
instantaneous blasting where all holes are fired essentially 
simultaneously. To estimate the maximum poundage of explosives that may 
be utilized for this project, the USACE has reviewed previous blasting 
projects that were conducted in San Juan Harbor, Puerto Rico in 2000 
and Miami Harbor, Florida in 2005. The San Juan Harbor project's 
heaviest confined blast was 170.1 kilograms (kg) (375 lbs) per delay 
and in Miami Harbor it was 60.8 kg (134 lbs) per delay. However, based 
on discussions with the USACE geotechnical engineers, the blasting 
energy required to break up rock in the East Channel of the Tampa 
Harbor Big Bend project will be reduced in effort to minimize impacts 
to the environment and obtain some fracturing of the rock to aid 
removal. Therefore, the maximum weight of delays will not exceed 18.1 
kg (40 lbs) for this project. Therefore, the proposed project will use 
a maximum charge weight of 725.7 kg (1,600 lbs) as a conservatively 
high estimate for the total amount of explosives that may be used in 
the largest blasting pattern (40 charges of 18.1 kg (40 lbs) each).
    The following industry standards and USACE Safety and Health 
Regulations will be implemented:
     The weight of explosives to be used in each blast event 
will be limited to the lowest kg (not to exceed 18.1 kg (40 lbs)/delay) 
of explosives that can adequately break the rock.
     Drill patterns shall be restricted to a minimum of 2.4 m 
(8 ft) separation from a loaded hole.
     Hours of blasting are restricted to two hours after 
sunrise until one hour before sunset to allow for adequate observation 
of the project area for protected species. Blasting hours will also be 
restricted to periods of good weather (no blasting will commence in 
rain, fog, or otherwise poor weather conditions, and can only commence 
when the entire Level B harassment zone is visible to observers).

[[Page 11971]]

     Selection of explosive products and their practical 
application method must address vibration and overpressure control for 
protection of existing structures and marine wildlife.
     Loaded blast holes will be individually delayed such that 
larger blasts are broken into smaller blasts with a time break between 
them that will be determined by the contractor. Loaded blast holes will 
be individually delayed to reduce the maximum kilograms/pounds per 
blast event (which will reduce the radius at which marine mammals may 
be injured or killed).
     The blast design will consider matching the energy in the 
``work effort'' of the borehole to the rock mass or target for 
minimizing excess energy vented into the water column or hydraulic 
shock.
     Delay timing adjustments between delay detonations to 
stagger the blast pressures and prevent cumulative addition of 
pressures in the water will be determined by the contractor, and will 
be in compliance with USACE regulations.
    Prior to implementing a blasting program, a test blast program will 
be completed. The test blast program will have all the same protection 
measures in place for protected species as blasting for construction 
purposes. The purpose of the text blast program is to demonstrate and/
or confirm the following:
     Drill boat capabilities and production rates;
     Ideal drill pattern for typical boreholes;
     Acceptable rock breakage for excavation;
     Tolerable vibration level emitted;
     Directional vibration;
     Calibration of the environment; and
     Sound parameters of the blasting by variables of the test 
blasting and production blasting.
    The test blast program will begin with a single row of individually 
delayed holes and progress up to the maximum production blast intended 
for use. The test blast program will take place in the project area and 
will count toward the pre-treatment of material, so it will be included 
in the 42-total-blast-events limit. Each test blast is designed to 
establish the limits of vibration and overpressure, with acceptable 
rock breakage for excavation. The final test blast event simulates the 
maximum explosive detonation as to size, overlying water depth, charge 
configuration, charge separation, initiation methods, and loading 
conditions anticipated for the typical production blast. The results of 
the test blast program will be the basis for developing a completely 
engineered procedure for the construction blasting plan. Specifically, 
the test blast program will be used to determine the following:
     Distance between individual charges (minimum 2.4 m (8 ft) 
requirement);
     Kilograms/pounds per delay (not to exceed 18.1 kg (40 lbs) 
per delay);
     Peak particle velocities (threshold limit value (TLV));
     Frequencies (TLV);
     Peak vector sum; and
     Overpressure.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see ``Proposed 
Mitigation'' and ``Proposed Monitoring and Reporting.'')

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the USACE IHA application summarize available 
information regarding status and trends, distribution and habitat 
preferences, and behavior and life history, of the potentially affected 
species. Additional information regarding population trends and threats 
may be found in NMFS's Stock Assessment Reports (SAR; 
www.nmfs.noaa.gov/pr/sars/) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS's website (www.nmfs.noaa.gov/pr/species/mammals/).
    Table 1 lists all species with known or potential for occurrence in 
the project area and offshore of the west central Florida coastline, 
and summarizes information related to the population or stock, 
including regulatory status under the MMPA and ESA and potential 
biological removal (PBR), where known. For taxonomy, we follow 
Committee on Taxonomy (2016). PBR is 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 (as described in NMFS's 
SARs). While no mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species and 
other threats.

                                          Table 1--Marine Mammals With Potentiac Occurrence in the Project Area
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                                                        Occurrence in      Stock population
            Species                    Habitat           project area        estimate \1\       ESA  status \2\     MMPA status \3\           PBR
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Humpback whale (Megaptera        Pelagic, nearshore  Rare...............  823--Gulf of Maine  NL                  NC                  13
 novaengliae).                    waters and banks.                        Stock.
Minke whale (Balaenoptera        Coastal, offshore.  Rare...............  2,591--Canadian     NL                  NC                  14
 acutorostrata).                                                           East Coast Stock.
Bryde's whale (Balaenoptera      Pelagic and         Rare...............  33--Northern Gulf   NL                  S                   0.03
 brydei).                         coastal.                                 of Mexico Stock.
Sei whale (Balaenoptera          Primarily           Rare...............  357--Nova Scotia    EN                  S                   0.5
 borealis).                       offshore, pelagic.                       Stock.
Fin whale (Balaenoptera          Slope, mostly       Rare...............  1,618--Western      EN                  S                   2.5
 physalus).                       pelagic.                                 North Atlantic
                                                                           Stock.
Blue whale (Balaenoptera         Pelagic and         Rare...............  440--Western North  EN                  S                   0.9
 musculus).                       coastal.                                 Atlantic Stock.
Sperm whale (Physeter            Pelagic, deep seas  Rare...............  763--Northern Gulf  EN                  S                   1.1
 macrcephalus).                                                            of Mexico Stock.
Dwarf sperm whale (Kogia sima).  Offshore, pelagic.  Rare...............  186--Northern Gulf  NL                  NC                  0.9
                                                                           of Mexico Stock.
Gervais' beaked whale            Pelagic, slope and  Rare...............  149--Northern Gulf  NL                  NC                  0.8
 (Mesoplodon europaeus).          canyons.                                 of Mexico Stock.

[[Page 11972]]

 
Sowerby's beaked whale           Pelagic, slope and  Rare...............  7,092--Western      NL                  NC                  0.8
 (Mesoplodon bidens).             canyons.                                 North Atlantic
                                                                           Stock.
Blainville's beaked whale        Pelagic, slope and  Rare...............  149--Northern Gulf  NL                  NC                  0.8
 (Mesoplodon densirostris).       canyons.                                 of Mexico Stock.
Cuvier's beaked whale (Ziphius   Pelagic, slope and  Rare...............  74--Northern Gulf   NL                  NC                  0.4
 cavirostris).                    canyons.                                 of Mexico Stock.
Killer whale (Orcinus orca)....  Widely distributed  Rare...............  28--Northern Gulf   NL                  NC                  0.1
                                                                           of Mexico Stock.
Short-finned pilot whale         Inshore and         Rare...............  2,415--Northern     NL                  NC                  15
 (Globicephala macrorhynchus).    offshore.                                Gulf of Mexico
                                                                           Stock.
False killer whale (Pseudorca    Pelagic...........  Rare...............  NA--Northern Gulf   NL                  NC                  Unknown
 crassidens).                                                              of Mexico Stock.
Melon-headed whale               Pelagic...........  Rare...............  2,335--Northern     NL                  NC                  13
 (Peponocephala electra).                                                  Gulf of Mexico
                                                                           Stock.
Pygmy killer whale (Feresa       Pelagic...........  Rare...............  152--Northern Gulf  NL                  NC                  0.8
 attenuata).                                                               of Mexico Stock.
Risso's dolphin (Grampus         Pelagic, shelf....  Rare...............  2,442--Northern     NL                  NC                  16
 griseus).                                                                 Gulf of Mexico
                                                                           Stock.
Common bottlenose dolphin        Offshore, inshore,  Common.............  564--Tampa Bay      NL                  S                   Unknown
 (Tursiops truncatus).            coastal, and                             Stock \4\.
                                  estuaries.
Rough-toothed dolphin (Steno     Pelagic...........  Rare...............  624--Northern Gulf  NL                  NC                  3
 bredanensis).                                                             of Mexico Stock.
Fraser's dolphin (Lagenodelphis  Shelf and slope...  Rare...............  NA--Northern Gulf   NL                  NC                  Unknown
 hosei).                                                                   of Mexico Stock.
Striped dolphin (Stenella        Coastal, shelf and  Rare...............  1,849--Northern     NL                  NC                  10
 coeruleoalba).                   slope.                                   Gulf of Mexico
                                                                           Stock.
Pantropical spotted dolphin      Coastal, shelf and  Uncommon...........  50,880--Northern    NL                  NC                  407
 (Stenella attenuata).            slope.                                   Gulf of Mexico
                                                                           Stock.
Atlantic spotted dolphin         Coastal to pelagic  Uncommon...........  NA--Northern Gulf   NL                  NC                  Unknown
 (Stenella frontalis).                                                     of Mexico Stock.
Spinner dolphin (Stenella        Mostly pelagic....  Uncommon...........  11,441--Northern    NL                  NC                  62
 longirostris).                                                            Gulf of Mexico
                                                                           Stock.
Clymene dolphin (Stenella        Coastal, shelf and  Uncommon...........  129--Northern Gulf  NL                  NC                  0.6
 clymene).                        slope.                                   of Mexico Stock.
West Indian manatee (Florida     Coastal, rivers,    Uncommon...........  6,620--Florida      T                   D                   ..................
 manatee) (Trichechus manatus     and estuaries.                           Stock \5\.
 latirostris).
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\1\ NMFS Marine Mammal Stock Assessment Reports (Hayes et al., 2016) unless indicated otherwise.
\2\ U.S. Endangered Species Act: EN = endangered; T = threatened; NL = not listed.
\3\ U.S. Marine Mammal Protection Act: D = depleted; S = strategic; NC = not classified.
\4\ Wells et al., 1995.
\5\ Florida Fish and Wildlife Conservation Commission Survey Data (USFWS jurisdiction).

    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All values presented in Table 1 are the most recent 
available at the time of publication and are available in the 2016 
Atlantic SAR (Hayes et al., 2016) with the exception of common 
bottlenose dolphin and the Florida manatee. The Florida manatee is not 
a species under NMFS jurisdiction, so is not included in the SAR. The 
abundance estimate from Wells et al. (1995) was used for bottlenose 
dolphins since abundance information is not provided for the Tampa Bay 
stock in the 2016 SAR.
    For Tampa Bay, Urian et al. (2009) described five discrete 
communities of common bottlenose dolphins (including the adjacent 
Sarasota Bay community) that differed in their social interactions and 
ranging patterns. Structure was found despite a lack of physiological 
barriers to movement within this large, open embayment. The authors 
further suggested that fine-scale structure may be a common element 
among bottlenose dolphins in the southeastern United States and 
recommended that management should account for fine-scale structure 
that exists within current stock designations. NMFS is in process of 
writing individual SARs for each of the 31 bay, sound, and estuary 
(BSE) stocks of common bottlenose dolphins. Until this effort is 
complete, Wells et al. (1995) provides the best available information 
regarding the abundance of the Tampa Bay stock of common bottlenose 
dolphins.
    All species under NMFS' jurisdiction that could potentially occur 
in the

[[Page 11973]]

proposed survey areas are included in Table 1. However, the temporal 
and/or spatial occurrence of all species except for common bottlenose 
dolphins is such that take is not expected to occur, and they are not 
discussed further beyond the explanation provided here. The confined 
blasting portion of the project is located within the East Channel of 
the Big Bend Channel in Tampa Harbor. Although marine mammal species 
other than common bottlenose dolphins may transit through the area 
offshore of Tampa Harbor, they are not anticipated to occur within the 
proposed project area.
    In addition to the species under NMFS jurisdiction that may be 
found in waters off the west central Florida coast, the Florida manatee 
(managed by USFWS) may also occur in the proposed project area. The 
USACE has coordinated with the USFWS for avoidance of take for this 
species. Therefore, the Florida manatee is not considered further in 
this document.
    The status of the common bottlenose dolphin stock in the project 
area relative to optimum sustainable population is unknown. This 
species is not listed as threatened or endangered under the Endangered 
Species Act (ESA). However, the occurrence of 13 Unusual Mortality 
Events (UME) among this species in the northern Gulf of Mexico coast 
since 1990 (Litz, et al., 2014) is cause for concern and the effects of 
the UMEs on stock abundance have not yet been determined for the Gulf 
of Mexico stocks, including the Tampa Bay stock (in part due to the 
fact that it has not been possible to assign mortalities to specific 
stocks because there is a lack of information on stock identification). 
NMFS considers each of the Gulf of Mexico stocks (including the Tampa 
Bay stock) to be strategic because most of the stock sizes are 
currently unknown, but likely small and relatively few mortalities and 
serious injuries may exceed PBR.
    Past studies have documented year-round residency of individual 
bottlenose dolphins in estuarine waters (Irvine et al., 1981; Shane, 
1977; and Gruber, 1981). As a result, the expectation of year-round 
resident populations was extended to BSE waters across the northern 
Gulf of Mexico. Since these early studies, long-term residency has been 
reported from nearly every site where photographic identification or 
tagging studies have been conducted in the Gulf of Mexico, including 
documentation of long-term residency in Tampa Bay (Wells, 1986; Wells 
et al., 1996; Urian et al., 2009).
    In many cases, residents occur primarily in BSE waters with limited 
movements through passes to the Gulf of Mexico (Shane, 1977 and 1990; 
Gruber, 1981; Irvine et al., 1981; Maze and Wursig, 1999; Lynn and 
Wursig, 2002; Fazioli et al., 2006). However, in some areas, year-round 
residents may co-occur with nonresident dolphins and mixing of inshore 
residents and non-residents has been documented in several places (Maze 
and Wursig, 1999; Quintana-Rizzo and Wells, 2001; and Shane, 2004). 
Non-residents exhibit a variety of movement patterns, ranging from 
apparent nomadism to apparent seasonal or non-seasonal migrations. 
Passes, especially the mouths of the larger estuaries, serve as mixing 
areas. For example, dolphins from several different areas were 
documented at the mouth of Tampa Bay (Wells, 1986).
    Seasonal movements of dolphins into and out of some of the bays, 
sounds, and estuaries have also been documented, and fall/winter 
increases in abundance have been noted for Tampa Bay (Scott et al., 
1989). In another example, Balmer et al. (2008) suggested that during 
summer and winter, St. Josephs Bay hosts dolphins that spend most of 
their time within this region, and these may represent a resident 
community, while in spring and fall, St. Joseph Bay is visited by 
dolphins that range outside of this area.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, 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 directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 dB 
threshold from the normalized composite audiograms, with the exception 
for lower limits for low-frequency cetaceans where the lower bound was 
deemed to be biologically implausible and the lower bound from Southall 
et al. (2007) retained. The hearing groups and the associated 
frequencies are indicated below (note that these frequency ranges 
correspond to the range for the composite group, with the entire range 
not necessarily reflecting the capabilities of every species within 
that group):
     Low-frequency cetaceans (mysticetes): Generalized hearing 
is estimated to occur between approximately 7 Hz and 35 kHz, with best 
hearing estimated to be from 100 Hz to 8 kHz;
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz, with best hearing from 10 to 
less than 100 kHz;
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): Generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz;
     Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz, 
with best hearing between 1-50 kHz; and
     Pinnipeds in water; Otariidae (eared seals): Generalized 
hearing is estimated to occur between 60 Hz and 39 kHz, with best 
hearing between 2-48 kHz.
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2016) for a review of available information. 
Common bottlenose dolphins have the reasonable potential to occur with 
the proposed survey activities, and are classified as mid-frequency 
cetaceans (i.e., all delphinid and ziphiid species and the sperm 
whale). As discussed previously, none of the other species under NMFS' 
jurisdiction listed in Table 1 are anticipated to occur in the proposed 
project location.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The ``Estimated Take by Incidental Harassment'' section 
later in this document includes a quantitative analysis of the number 
of individuals that are expected to be taken by this activity. The 
``Negligible Impact

[[Page 11974]]

Analysis and Determination'' section considers 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 these activities on the reproductive success or 
survivorship of individuals and how those impacts on individuals are 
likely to impact marine mammal species or stocks.

Description of Sound Sources and Sound Types Associated With the 
Proposed Activities

    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. 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 we reference all underwater sound levels in this 
document to a pressure of 1 [micro]Pa and all airborne sound levels in 
this document are referenced to a pressure of 20 [micro]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 one can account for the values 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; and
     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 sounds produced by the proposed confined blasting activities 
are considered impulsive, which is one of two general sound types, the 
other being non-pulsed. 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 Southall et al. (2007) for an in-
depth discussion of these concepts.
    Impulsive 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) and occur either as 
isolated events or repeated in some succession. These sounds have 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

[[Page 11975]]

injury as compared with sounds that lack these features.

Acoustic Impacts

    Please refer to the information given previously (Description of 
Sound Sources) regarding sound, characteristics of sound types, and 
metrics used in this document. Anthropogenic sounds cover a broad range 
of frequencies and sound levels and can have a range of highly variable 
impacts on marine life, from none or minor to potentially severe 
responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: Temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et 
al., 2009). The degree of effect is intrinsically related to the signal 
characteristics, received level, distance from the source, and duration 
of the sound exposure. In general, sudden, high level sounds can cause 
hearing loss, as can longer exposures to lower level sounds. Temporary 
or permanent loss of hearing will occur almost exclusively for noise 
within an animal's hearing range. We first describe specific 
manifestations of acoustic effects before providing discussion specific 
to the confined blasting activities.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the animal, but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., certain non-auditory 
physical or physiological effects and mortality) only briefly as we do 
not expect that there is a reasonable likelihood that USACE's confined 
blasting activities may result in such effects (see below for further 
discussion). Marine mammals exposed to high-intensity sound, or to 
lower-intensity sound for prolonged periods, can experience hearing 
threshold shift (TS), which is the loss of hearing sensitivity 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 fully recoverable, or temporary 
(TTS), in which case the animal's hearing threshold would recover over 
time (Southall et al., 2007). Repeated sound exposure that leads to TTS 
could cause PTS. In severe cases of PTS, there can be total or partial 
deafness, while in most cases the animal has an impaired ability to 
hear sounds in specific frequency ranges (Kryter, 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several decibels above that which induces mild TTS: A 40-dB 
threshold shift approximates PTS onset (e.g., Kryter et al., 1966; 
Miller, 1974), whereas a 6-dB threshold shift approximates TTS onset 
(e.g., Southall et al., 2007). Based on data from terrestrial mammals, 
a precautionary assumption is that the PTS thresholds for impulse 
sounds (such as bombs) are at least 6 dB higher than the TTS threshold 
on a peak-pressure basis and PTS cumulative sound exposure level 
thresholds are 15 to 20 dB higher than TTS cumulative sound exposure 
level thresholds (Southall et al., 2007). Given the higher level of 
sound or longer exposure duration necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS could occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity 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 data published at the time 
of this writing concern TTS elicited by exposure to multiple pulses of 
sound.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to 
serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time where ambient noise is lower and there 
are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise (Phocoena phocoena), and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal (Mirounga angustirostris), harbor seal (Phoca vitulina), and 
California sea lion (Zalophus californianus)) exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (e.g., Finneran et al., 2002; Nachtigall et al., 
2004; Kastak et al., 2005; Lucke et al., 2009; Popov et al., 2011). 
Additionally, the existing marine mammal TTS data come from a limited 
number of individuals within these species. For summaries of data on 
TTS in marine mammals or for further discussion of TTS onset 
thresholds, please see Southall et al. (2007) and Finneran and Jenkins 
(2012).
    Behavioral disturbance may include a variety of effects, including 
subtle changes in behavior (e.g., minor or brief avoidance of an area 
or changes in vocalizations), more conspicuous changes in similar 
behavioral activities, and more sustained and/or potentially

[[Page 11976]]

severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses to sound are highly variable and 
context-specific and any reactions depend on numerous intrinsic and 
extrinsic factors (e.g., species, state of maturity, experience, 
current activity, reproductive state, auditory sensitivity, time of 
day), as well as the interplay between factors (e.g., Richardson et 
al., 1995; Wartzok et al., 2003; Southall et al., 2007; Weilgart, 2007; 
Archer et al., 2010). Behavioral reactions can vary not only among 
individuals but also within an individual, depending on previous 
experience with a sound source, context, and numerous other factors 
(Ellison et al., 2012), and can vary depending on characteristics 
associated with the sound source (e.g., whether it is moving or 
stationary, number of sources, distance from the source). Please see 
Appendices B-C of Southall et al. (2007) for a review of studies 
involving marine mammal behavioral responses to sound.
    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. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009).
    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. As noted, behavioral state may 
affect the type of response. 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 have shown 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 
airguns or acoustic harassment devices) have been varied but often 
consist of avoidance behavior or other behavioral changes suggesting 
discomfort (Morton and Symonds, 2002; see also Richardson et al., 1995; 
Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a, b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007b). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).

[[Page 11977]]

    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    An animal's perception of a threat may be sufficient to trigger 
stress responses consisting of some combination of behavioral 
responses, autonomic nervous system responses, neuroendocrine 
responses, or immune responses (e.g., Seyle, 1950; Moberg, 2000). In 
many cases, an animal's first and sometimes most economical (in terms 
of energetic costs) response is behavioral avoidance of the potential 
stressor. Autonomic nervous system responses to stress typically 
involve changes in heart rate, blood pressure, and gastrointestinal 
activity. These responses have a relatively short duration and may or 
may not have a significant long-term effect on an animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, ``distress'' occurs when an animal does 
not have sufficient energy reserves to satisfy the energetic costs of a 
stress response. In that case, energy resources must be diverted from 
other functions. This state of distress will last until the animal 
replenishes its energetic reserves sufficient to restore normal 
function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).
    Sound can disrupt behavior through masking, or interfering with, an 
animal's ability to detect, recognize, or discriminate between acoustic 
signals of interest (e.g., those used for intraspecific communication 
and social interactions, prey detection, predator avoidance, 
navigation) (Richardson et al., 1995). Masking occurs when the receipt 
of a sound is interfered with by another coincident sound at similar 
frequencies and at similar or higher intensity, and may occur whether 
the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., shipping, sonar, seismic 
exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (signal-to-noise ratio, 
temporal variability, direction), in relation to each other and to an 
animal's hearing abilities (sensitivity, frequency range, critical 
ratios, frequency discrimination, directional discrimination, age or 
TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. 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.

[[Page 11978]]

    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark, 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore, 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. 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, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Non-auditory physiological effects or injuries that theoretically 
might occur in marine mammals exposed to high level underwater sound, 
or as a secondary effect of extreme behavioral reactions (e.g., change 
in dive profile as a result of an avoidance reaction) caused by 
exposure to sound include neurological effects, bubble formation, 
resonance effects, and other types of organ or tissue damage (Cox et 
al., 2006; Southall et al., 2007; Zimmer and Tyack, 2007). USACE's 
activities involve the use of explosives that are associated with these 
types of effects; however, severe injury to marine mammals is not 
anticipated from these activities due to the mitigation measures in 
place to avoid these types of impacts.
    When a marine mammal swims or floats onto shore and is incapable of 
returning to sea, the event is termed a ``stranding'' (16 U.S.C. 
1421h(3)). Marine mammals are known to strand for a variety of reasons, 
such as infectious agents, biotoxicosis, starvation, fishery 
interaction, ship strike, unusual oceanographic or weather events, 
sound exposure, or combinations of these stressors sustained 
concurrently or in series (e.g., Geraci et al., 1999). However, the 
cause or causes of most strandings is unknown (e.g., Best, 1982). 
Combinations of dissimilar stressors may combine to kill an animal or 
dramatically reduce its fitness, even though one exposure without the 
other would not be expected to produce the same outcome (e.g., Sih et 
al., 2004). For further description of stranding events see, e.g., 
Southall et al., 2006; Jepson et al., 2013; Wright et al., 2013.
    The USACE's proposed confined blasting activities have the 
potential to take marine mammals by exposing them to impulsive noise 
and pressure waves generated by detonations of explosives. Exposure to 
energy, pressure, or direct strike has the potential to result in non-
lethal injury (Level A harassment), disturbance (Level B harassment), 
serious injury, and/or mortality. Explosive detonations send a shock 
wave and sound energy through the water and can release gaseous by-
products, create an oscillating bubble, or cause a plume of water to 
shoot up from the water surface (though this energy is reduced by as 
much as 60-90 percent by confining the blast as discussed above). The 
shock wave and accompanying noise are of most concern to marine 
animals. Depending on the intensity of the shock wave and size, 
location, and depth of the animal, an animal can be injured, killed, 
suffer non-lethal physical effects, experience hearing related effects 
with or without behavioral responses, or exhibit temporary behavioral 
responses or tolerance from hearing the blast sound. Generally, 
exposures to higher levels of impulse and pressure levels would result 
in greater impacts to an individual animal.
    The effects of underwater detonations on marine mammals are 
dependent on several factors, including the size, type, and depth of 
the animal; the depth, intensity, and duration of the sound; the depth 
of the water column; the substrate of the habitat; the standoff 
distance between activities and the animal; and the sound propagation 
properties of the environment. Thus, we expect impacts to marine 
mammals from the confined blasting activities to result primarily from 
acoustic pathways. As such, the degree of the effect relates to the 
received level and duration of the sound exposure, as influenced by the 
distance between the animal and the source. The further away from the 
source, the less intense the exposure should be.
    The potential effects of underwater detonations from the proposed 
confined blasting activities may include 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., 2004; Nowacek et al., 2007; Southall et 
al., 2007). However, the effects of noise on marine mammals are highly 
variable, often depending on species and contextual factors (based on 
Richardson et al., 1995).
    In the absence of mitigation, impacts to marine species as a result 
of the USACE confined blasting could 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.

Disturbance Reactions

    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Numerous studies have shown that underwater sounds are often readily 
detectable by marine mammals in the water at distances of many 
kilometers. However, other studies have shown that marine mammals at 
distances more than a few kilometers away often show no apparent 
response to activities of various types (Miller et al., 2005). This is 
often true even in cases when the sounds must be readily audible to the 
animals based on measured received levels and the hearing sensitivity 
of that mammal group. Although various baleen whales, toothed whales, 
and (less frequently) pinnipeds have been shown to react behaviorally 
to underwater sound from impulsive sources, at other times, mammals of 
all three types have shown no overt reactions (e.g., Malme et al., 
1986; Richardson et al., 1995; Madsen and Mohl, 2000; Croll et al., 
2001; Jacobs and Terhune, 2002; Madsen et al., 2002; MacLean and Koski, 
2005; Miller et al., 2005; Bain and Williams, 2006).

[[Page 11979]]

    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) 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., 2004; Wartzok et al., 2003; 
Nowacek et al., 2007).
    Because the few available studies show wide variation in response 
to underwater sound, it is difficult to quantify exactly how sound from 
the USACE confined blasting activities would affect marine mammals. It 
is likely that the onset of confined detonations 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: 
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); or avoidance of 
areas where sound sources are located (Richardson et al., 1995).
    The biological significance of any of these behavioral disturbances 
is difficult to predict, especially if the detected disturbances appear 
minor. However generally, one could expect the consequences of 
behavioral modification 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 interferes with by another 
coincident sound at similar frequencies and at similar or higher levels 
(Clark et al., 2009). While it may occur temporarily, we do not expect 
auditory masking to result in detrimental impacts to an individual's or 
population's survival, fitness, or reproductive success. As no blasting 
would commence if dolphins (or any other protected species) are located 
within the East Channel (see discussion of Mitigation, below), dolphin 
movement would not be restricted within the proposed project area, 
allowing for movement out of the area to avoid masking impacts and the 
sound resulting from the detonations is short in duration. Also, 
masking is typically of greater concern for those marine mammals that 
utilize low frequency communications, such as baleen whales and, as 
such, is not likely to occur for marine mammals in the proposed project 
area.

Anticipated Effects on Habitat

    Confined detonations would result in temporary changes to the water 
environment. Explosions could send a shock wave and blast noise through 
the water, release gaseous by-products, create an oscillating bubble, 
and cause a plume of water to shoot up from the water surface. However, 
these effects would be temporary and not expected to last more than a 
few seconds. In addition, as discussed above, due to the fact that the 
blasts will be confined, the energy would be reduced by 60 to 90 
percent compared to open water blasting, so these effects would be 
lessened significantly. USACE does not expect any long-term impacts 
with regard to hazardous constituents to occur, as the explosives 
utilized are water-soluble and non-toxic. In the event that a charge is 
unable to be fired and must be left in the drillhole, it is designed to 
break down as it is made of ammonium nitrate in a fluid gel format. Any 
material left in the drill hole after blasting would be recovered 
through the dredging process. USACE considered water quality impacts 
within its EA and determined the primary anticipated change in water 
quality at the expansion and maintenance dredging areas would be a 
temporary increase in turbidity.
    According to the State of Florida's Class III water quality 
standards, turbidity levels during dredging are not to exceed 29 
nephelometric turbidity units (NTUs) above background levels at the 
edge of normally a 150-meter mixing zone. Turbidity will be monitored 
according to State protocols and work would cease if at any time the 
turbidity exceeded this standard.
    The bottom of the East Channel consists of previously dredged rock 
and unconsolidated sediment, as the proposed project area is a 
historically a manmade channel that has been deepened and maintenance 
dredged. With exception of the proposed deepening, the physical nature 
of the habitat is not expected to significantly change and should 
continue to be utilized by dolphins in a similar manner as currently 
utilized (assumed to be socializing, feeding, resting, etc., though the 
Channel is not an area of known biological importance for any of these 
uses). With regard to prey species (mainly fish), a very small number 
of fish are expected to be impacted by the proposed project. Based on 
the results of the 2005 blasting project at Miami Harbor, the blasting 
consisted of 40 blast events over a 38-day time period. Of these 40 
blast events, 23 (57.5 percent) were monitored by the State and had 
injured and dead fish collected after the ``all clear'' was given 
following blasting (note that this is normally at least 2-3 minutes 
after the shot, and seagulls and frigate birds quickly learned to 
approach the blast site and forage on some of the stunned, injured, and 
dead fish floating at the surface). Volunteers collected carcasses of 
floating fish (also noting that not all fish float after a blast but 
due to safety concerns, there was no method to collect non-floating 
carcasses). A summary of the data showed that 24 different genera were 
collected during the Miami Harbor blasting events and the total number 
of fish collected was 288, or an average of 12.5 fish per blast 
(ranging from 3 to 38). Factors that affect fish mortality include, but 
are not limited to fish size, body shape (fusiform, etc.), proximity of 
the blast to a vertical structure (smaller charge weights resulted in 
high fish kills when close to a bulkhead).
    To reduce the potential for fish to be injured or killed, the USACE 
has previously utilized a small, unconfined explosive charge (usually 
0.45 kg (1 lb)) to be detonated approximately 30 seconds before the 
main blast to drive fish away from the blasting zone. It is assumed 
that noise or pressure generated by the small charge would drive fish 
from the immediate area, thereby reducing impacts from the larger and 
potentially more damaging blast. There is limited data available on the 
effectiveness of fish-scare charges at actually reducing the magnitude 
of fish

[[Page 11980]]

kills, and the effectiveness may be based on the fish's life history. 
However, based on the monetary value of fish, including high value 
commercial or recreational species like snook and tarpon that can be 
found in west central Florida inlets like Tampa Bay, the low cost 
associated with the repelling charge use would be offset even if only a 
few fish were moved from the kill zone (Keevin et al., 1997).
    To calculate the potential loss of prey species from the proposed 
project area as a result of the confined blasting, a 12.5 per-blast 
kill estimate (based on the Miami Harbor blast study discussed above) 
was used. It is estimated that approximately 525 fish would be killed 
by the proposed confined blasting within the East Channel (12.5 fish/
blast multiplied by 42 detonations). Therefore, prey availability would 
not be significantly impacted due to the proposed project.
    While we anticipate that the specified activity may result in 
marine mammals avoiding certain areas due to temporary ensonification, 
this impact to habitat and prey resources would be temporary and 
reversible. The main impact associated with the proposed activity would 
be temporarily elevated noise levels and the associated direct effects 
on marine mammals, previously discussed in this notice. Marine mammals 
are anticipated to temporarily vacate the area of live detonations. 
However, these events are usually of short duration, and we anticipate 
that animals will return to the activity area during periods of non-
activity. Thus, based on the preceding discussion, we do not anticipate 
that the proposed activity would have any habitat-related effects that 
could cause significant or long-term consequences for individual marine 
mammals or their populations.
    No takes of marine mammals are anticipated, nor are any being 
proposed for authorization, related to the dredging activities within 
the Big Bend Channel (including within the East Channel, where the 
proposed confined blasting will occur). Various types of dredging 
equipment are anticipated to be utilized in the course of this 
construction dredging project and may include Mechanical (Clamshell 
and/or Backhoe) and Hydraulic (Hopper and/or Cutter-Suction). Dredging 
and direct pumping of material to the placement site is expected, and 
there will likely be a need for a pipeline to cross the channel at 
certain locations in order to pump material into the upland placement 
area. Any such crossing would require that the top of the pipeline 
remain below -12.5 m (41 ft) mean lower low water (MLLW), which is the 
lowest height of the average tide recorded for a given location. 
Placement of the pipeline below -12.5 m MLLW would allow dolphins to 
transit through this portion of the project area unimpeded and is not 
anticipated to cause take.
    In general, potential impacts to marine mammals from explosive 
detonations could include mortality, serious injury, as well as Level A 
harassment (non-lethal injury/permanent threshold shift (PTS)) and 
Level B harassment (temporary threshold shift (TTS)/behavioral 
harassment). In the absence of mitigation, marine mammals could be 
killed or injured as a result of an explosive detonation due to the 
response of air cavities in the body, such as the lungs and bubbles in 
the intestines. A second potential possible cause of mortality (in the 
absence of mitigation) is the onset of extensive lung hemorrhage. 
Extensive lung hemorrhage is considered debilitating and potentially 
fatal. Suffocation caused by lung hemorrhage is likely to be the major 
cause of marine mammal death from underwater shock waves. The estimated 
range for the onset of extensive lung hemorrhage to marine mammals 
varies depending upon the animal's weight, with the smallest mammals 
having the greatest potential hazard range.
    Table 2 provides criteria and thresholds related to auditory 
impacts as well as non-auditory impacts based on NMFS Acoustic 
Technical Guidance for Assessing the Effects of Anthropogenic Sound on 
Marine Mammal Hearing (NMFS 2016), and Finneran and Jenkins (2012). 
Acoustic thresholds related to TTS and PTS onset are also provided in 
Table 2 based on NMFS 2016 Acoustic Technical Guidance. For impulse 
sources (such as explosives), NMFS 2016 includes thresholds expressed 
as weighted, cumulative sound exposure levels (SELcum) and unweighted 
peak sound pressure levels (PK). Because of limited data on behavioral 
reactions of marine mammals to multiple detonations, behavioral 
thresholds are derived directly from TTS onset thresholds (i.e., 
behavioral thresholds are five dB lower than TTS onset thresholds).

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of whether the number of takes is ``small'' and the 
negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. 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).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns and/or TTS for individual marine 
mammals resulting from exposure to noise from underwater confined 
blasting in the East Channel of the Big Bend Channel, Tampa Harbor. 
Based on the nature of the activity and the anticipated effectiveness 
of the mitigation measures (i.e., no blasting if marine mammals (or any 
protected species) are within the East Channel, which encompasses the 
entirety of the Level A take zone, as discussed in detail below in 
Proposed Mitigation section), Level A harassment is neither anticipated 
nor proposed to be authorized.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Described in the most basic way, we estimate take by considering: 
(1) Thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment or tissue damage; (2) the area 
or volume of water that will be ensonified above these levels in a day; 
(3) the density or occurrence of marine mammals within these ensonified 
areas; and, (4) and the number of days of activities. Below, we 
describe these components in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment). Thresholds have also 
been developed to identify the pressure levels above which animals may 
incur different types of tissue damage from exposure to pressure waves 
from explosive detonation.

[[Page 11981]]

    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and peer reviewers to inform the final product, and are 
provided in the table below. The references, analysis, and methodology 
used in the development of the thresholds are described in NMFS 2016 
Technical Guidance, which may be accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                Table 2--NMFS' Current Thresholds and Criteria for Impact Analysis From the Use of Explosives for Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
        Hearing group               Species          Behavioral           TTS              PTS         GI tract injury    Lung injury       Mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans......  Most delphinids,  165 dB...........  170 dB SELcum;   185 dB SELcum;   237 dB..........  39.1 M1/3        91.4 M1/3
                                medium and                           224 dB PK.       230 dB PK.                         (1+[DRm/         (1+[DRm/
                                large toothed                                                                            10.081])1/2 Pa-  10.081])1/2 Pa-
                                whales.                                                                                  sec.             sec.
                                                                                                                        Where: M = mass  Where: M = mass
                                                                                                                         of the animals   of the animals
                                                                                                                         in kg.           in kg.
                                                                                                                        DRm = depth of   DRm = depth of
                                                                                                                         the receiver     the receiver
                                                                                                                         (animal) in      (animal) in
                                                                                                                         meters.          meters.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Explosive sources--Based on the best available science, NMFS uses 
the acoustic and pressure thresholds indicated in Table 2 above to 
predict the onset of behavioral harassment, TTS, PTS, tissue damage, 
and mortality.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    Radii for Level A and Level B harassment were calculated using 
algorithms specifically developed for confined underwater blasting 
operations by the NMFS (see Attachment B of the application, which 
provides more detail and spreadsheet results). The algorithms compute 
the cumulative sound exposure impact zone due to a pattern of charges. 
The code calculates the total explosive energy from all charges through 
a summation of the individual energy emanating from each charge as a 
function of temporal and spatial separation of charges. Acoustical 
transmission loss is assumed to occur through cylindrical spreading. 
The SEL of the first detonation and each subsequent detonation is 
summed and transmission loss of acoustic energy due to cylindrical 
spreading is subtracted from the total SEL. Ultimately, the distance 
where the received level falls to a set SEL is calculated by spherical 
spreading of the total SEL (refer to section 6 and Attachment B of the 
IHA application for more information on how this was modeled). However, 
the proposed blasting would occur within the East Channel, which is 
open to the Hillsborough Bay on the west side of the channel, but 
confined by land on the north, east, and south sides of the channel. 
NMFS and USACE agree that acoustic energy emanating from the East 
Channel and into Hillsborough Bay would rapidly decrease as the energy 
spreads to the north and south outside of the East Channel in the Bay. 
Under these conditions, sound energy beyond a 45 degree angle, or a 45 
degree cone shape outside of the channel mouth would attenuate, and 
would not result in Level B take.
    Level A and B take zones (km\2\) were calculated using the 
calculated blasting radii. Some blasting radii are contained within the 
water column or between the East Channel's north and south shorelines. 
These areas therefore are circular in shape. However, larger blasting 
radii extend beyond the channel's shorelines. In these cases, the areas 
form an irregular polygon shape that are bounded by the channel's 
shoreline to the north, east, and south and are cone-shaped outside of 
the East Channel opening to Tampa/Hillsborough Bay. The areas of these 
irregular polygon shapes were determined with computer software (Google 
Earth Pro). This area was then multiplied by the density calculated for 
common bottlenose dolphins in the project area, as this is the only 
marine mammal species potentially occurring in the East Channel 
(density information provided below). Figure 10 of the application 
illustrates the take areas calculated for the largest blast pattern 
consisting of 18.1 kg (40 lbs)/delay and 40 individual charges, which 
was used to calculate estimated take for the confined blasting 
activities.
    We note here that, even in absence of mitigation measures to avoid 
Level A take, due to the small Level A harassment zone and density of 
bottlenose dolphins in the proposed project area, Level A take is not 
anticipated (the maximum calculated take by Level A harassment is 0.02 
dolphin). In addition to this, mitigation measures (discussed below) 
will further ensure that no takes by Level A harassment will occur.

Marine Mammal Occurrence/Density Calculation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    As stated above, common bottlenose dolphins are the only species of 
marine mammal anticipated to occur in the proposed project area. Using 
photo-identification methods, Urian et al. (2009) identified 858 
individual dolphins during their 6-year study in the Tampa Bay. 
However, as stated above, data from Wells et al. (1995) was used for 
the abundance estimate of the Tampa Bay Stock of common bottlenose 
dolphins, as Urian et al. (2009) was not an abundance estimate, but a 
population structure study. The Wells et al. (1995) mark-resight method 
provided the most conservative, or highest average, abundance of 564 
common bottlenose dolphins within the 852-km\2\ study area. In order to 
calculate take, the USACE made an assumption that the dolphins would be 
evenly distributed throughout Tampa Bay. The number of dolphins per 
square kilometer within this area is calculated as 0.66 (564 dolphins / 
852 km\2\ = 0.66 dolphins/km\2\).

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    The USACE proposes a maximum charge weight of 725.7 kg (1,600 lbs) 
as a conservatively high estimate for the total amount of explosives 
that may be used in the largest blasting pattern. This is based on the 
fact that the maximum charge weight per delay would not exceed 18.1 kg 
(40 lbs)/delay for this project and the maximum number of charges per 
pattern would not exceed 40. Please refer to Table 3 of the application 
for the level of take associated with this charge weight as well as 
other charge weights. Figure 10

[[Page 11982]]

of the application provides visual representation of take areas plotted 
on an aerial photograph for 18.1 kg/delay.
    A maximum of 42 blast events would occur over the one year period 
of this IHA. Using the Tampa Bay Stock abundance estimate (n = 564), 
the density of common bottlenose dolphins occurring within the 
footprint of the project (0.66 dolphins/km\2\), as well as the maximum 
charge weight of 18.1 kg (40 lbs)/delay, the USACE is requesting Level 
B take for behavioral harassment and/or TTS for up to 5.8 common 
bottlenose dolphins per blast (refer to Table 3 of the application). 
Therefore, using the maximum amount of explosives per blast event and 
the maximum number of blast events, an estimated 244 Level B takes 
would occur over the one-year period of this IHA (5.8 dolphin/blast x 
42 detonations = 243.6 exposures). However, the number of dolphins 
subjected to TTS and/or behavioral harassment is expected to be 
significantly lower for two reasons. First, the USACE will implement a 
test blast program to determine the smallest amount of explosives 
needed to fracture the rock and allow mechanical removal. This test 
blast program would begin with a single row pattern of charges, and 
would vary the number and charges/pattern as well as the charge weight/
delay to determine the minimum needed and these test blasts would count 
toward the maximum of 42 total blast events. The maximum 1,600 lb 
blasting pattern of 18.1 kg (40 lb)/delay and 40 individual charges was 
used to calculate take due to the uncertainty regarding the minimum 
needed charge/delay and individual charges as well as uncertainty 
regarding the number of test blasts. Therefore, there would not 
actually be 42 blast events with the full pattern of 40 delays at full 
charge weight/delay (1,600 lb), as was assumed in the take calculation, 
and the take estimate is a conservative estimate. Second, we expect at 
least some of the exposures to be repeat exposures of the same 
individuals, as discussed further in the Small Numbers section below.

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 (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned) the likelihood of effective implementation (probability 
implemented as planned) and;
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    As discussed previously, the USACE will confine the blasts within 
the East Channel by boring holes into the existing rock, placing 
explosive charges within the holes, and stemming the holes in order to 
greatly reduce the energy released into the water column from the 
blasts (estimated to reduce the amount of energy by 60-90 percent 
versus open water blasting). In addition to utilizing the confined 
blasting, the following conditions will be incorporated into the 
project specifications to reduce the risk of impacts to marine mammals:
     Confined blasting will be restricted to the East Channel 
only;
     Blasting will be restricted to the months of April through 
October (this is to avoid impacts to Florida manatee, but may also 
serve to avoid impacts if there are seasonal increases in Tampa Bay/
proposed project area during the fall/winter as reported by Scott et 
al. (1989), and discussed above);
     The blasting plan shall be provided for NMFS review at 
least 30 days prior to work, and the blasting plan must include 
detailed information about the protected species watch program as well 
as details about proposed blasting events (to be submitted to NMFS 
headquarters Protected Species Division as well as the NMFS Southeast 
Regional Office, the State Fish and Wildlife Commission (FWC) Office, 
and USFWS);
    [cir] The blasting plan shall include:
    [ssquf] A list of the observers, their qualifications, and 
positions for the watch, including a map depicting the proposed 
locations for boat or land-based observers. Qualified observers must 
have prior on-the-job experience observing for protected marine species 
(such as dolphins, manatees, marine turtles, etc.) during previous in-
water blasting events where the blasting activities were similar in 
nature to this project;
    [ssquf] The amount of explosive charge proposed, the explosive 
charge's equivalency in TNT, how it will be executed (depth of 
drilling, stemming information, etc.), a drawing depicting the 
placement of the charges, size of the safety radius and how it will be 
marked (also depicted on a map), tide tables for the blasting event(s), 
and estimates of times and days for blasting events (with an 
understanding this is an estimate, and may change due to weather, 
equipment, etc.). Certain blasting restrictions will be imposed 
including the following: (1) Individual charge weights shall not exceed 
18.1 kg (40 lbs)/delay, and (2) the contractor shall not exceed a total 
of 42 blast events during the blast window.
     In addition to review of the blasting plan, NMFS's 
Southeast Region Office and State FWC shall be notified at the 
beginning (24 hours prior) and after (24 hours after) any blasting;
     For each explosive charge placed, three zones will be 
calculated, denoted on monitoring reports and provided to protected 
species observers before each blast for incorporation in the watch plan 
for each planned detonation. All of the zones will be noted by buoys 
for each of the blasts. These zones are:
    [cir] Level A Take Zone: The Level A Take Zone is equal to the 
radius of the PTS Injury Zone. As shown in the application in Table 3, 
as well as Figure 10, all other forms of injurious take (i.e. gastro-
intestinal injury, lung injury) and mortality have smaller radii than 
the PTS Injury Zone. Detonation shall not occur if a protected species 
is known to be (or based on previous sightings, may be) within the 
Level A Take Zone;
    [cir] Exclusion Zone: A zone which is the Level A Take Zone + 152.4 
m (500 ft). Detonation will not occur if a

[[Page 11983]]

protected species is known to be (or based on previous sightings, may 
be) within the Exclusion Zone;
    [cir] Level B Take Zone: The Level B Take Zone extends from the 
Exclusion Zone to the Behavior Zone radius. Detonation shall occur if a 
protected species is within the Level B Take Zone. Any protected 
species within this zone shall be monitored continuously and, if they 
are within the Level B Take Zone during detonation, then they shall be 
recorded on monitoring forms. Note that the Level B Take Zone should 
begin immediately beyond the end of the Level A Take Zone. However, the 
USACE proposes to implement an Exclusion Zone. Also, the area 
immediately beyond the Level B Take Zone shall also be monitored for 
protected species.
     No blasting shall occur within East Channel if dolphins or 
any other protected species are present within the East Channel (Note: 
The Level A harassment zone is entirely within the East Channel, which 
is why no Level A harassment is proposed for authorization);
     Protected species observers (PSOs) shall begin the watch 
program at least one hour prior to the scheduled start of the blasting 
activities, and will continue for at least one half hour after blast 
activities have completed;
     The watch program shall consist of a minimum of six PSOs 
with a designated lead observer. Each observer shall be equipped with a 
two-way radio that shall be dedicated exclusively to the watch. Extra 
radios shall be available in case of failures. All of the observers 
shall be in close communication with the blasting subcontractor in 
order to halt the blast event if the need arises. If all observers do 
not have working radios and cannot contact the primary observer and the 
blasting subcontractor during the pre-blast watch, the blast shall be 
postponed until all observers are in radio contact. Observers will also 
be equipped with polarized sunglasses, binoculars, a red flag for 
backup visual communication, and a sighting log with a map to record 
sightings;
     All blasting events will be weather dependent. Climatic 
conditions must be suitable for adequate viewing conditions. Blasting 
will not commence in rain, fog or otherwise poor weather conditions, 
and can only commence when the entire Level A Take Zone, Exclusion 
Zone, and Level B Take Zone are visible to observers;
     The PSO program will also consist of a continuous aerial 
survey conducted as approved by the Federal Aviation Administration 
(FAA). The blasting event shall be halted if an animal is spotted 
approaching or within the Exclusion Zone. An ``all-clear'' signal must 
be obtained from the aerial observer before detonation can occur. Note 
that all observers must give the ``all-clear'' signal before blasting 
can commence. The blasting event shall be halted immediately upon 
request of any of the observers. If animals are sighted, the blast 
event shall not take place until the animal moves out of the Exclusion 
Zone on its own volition. Animals shall not be herded away or harassed 
into leaving. Specifically, the animals must not be intentionally 
approached by project watercraft. Blasting may only commence when 30 
minutes have passed without an animal being sighted within or 
approaching the Exclusion Zone or Level A Take Zone;
     If multiple blast events take place in one day, blast 
events shall be separated by a minimum of six hours;
     After each blast, the observers and contractors shall meet 
and evaluate any problems encountered during blasting events and 
logistical solutions shall be presented to the Contracting Officer. 
Corrections to the watch shall be made prior to the next blasting 
event. If any one of the aforementioned conditions (bullet points 
directly above) is not met prior to or during the blasting, the 
contractor as advised by the watch observers shall have the authority 
to terminate the blasting event, until resolution can be reached with 
the Contracting Officer. The USACE will contact FWC, USFWS and NMFS;
     If an injured or dead protected species is sighted after 
the blast event, the watch observers shall contact the USACE and the 
USACE will contact the resource agencies at the following phone 
numbers:
    [cir] FWC through the Manatee Hotline: 1-888-404-FWCC and 850-922-
4300;
    [cir] USFWS Jacksonville: 904-731-3336;
    [cir] NMFS Southeast Region: 772-570-5312, and Emergency Stranding 
Hotline--1-877-433-8299.
     The observers shall maintain contact with the injured or 
dead protected species to the greatest extent practical until 
authorities arrive. Blasting shall be postponed until consultations are 
completed and determinations can be made of the cause of injury or 
mortality. If blasting injuries are documented, all demolition 
activities shall cease. The USACE will then submit a revised plan to 
FWC, NMFS and USFWS for review.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means effecting the least practicable impact on the 
affected 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 
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. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (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 marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.
    With some exceptions, the USACE will rely upon the same monitoring 
protocol developed for the Port of

[[Page 11984]]

Miami project in 2005 (Barkaszi, 2005) and published in Jordan et al., 
2007. A summary of that protocol is summarized here.
    A watch plan will be formulated based on the required monitoring 
radii and optimal observation locations. The watch plan will consist of 
at least six observers including at least one (1) aerial observer, two 
(2) boat-based observers, and two (2) observers stationed on the drill 
barge (Figures 12, 13, 14, & 15). The 6th observer will be placed in 
the most optimal observation location (boat, barge or aircraft) on a 
day-by-day basis depending on the location of the blast and the 
placement of dredging equipment. There shall also be one lead observer. 
This process will insure complete coverage of the three zones as well 
as any critical areas. The watch will begin at least 1 hour prior to 
each blast and continue for one half-hour after each blast (Jordan et 
al 2007).
    Boat-based observers will be placed on vessels with viewing 
platforms. The boat observers will cover the Level B Take Zone where 
waters are deep enough to safely operate the vessel. The aerial 
observer will fly in a helicopter with doors removed at an average 
height of 500 ft. The helicopter will drop lower if they need to 
identify something in the water. This will provide maximum visibility 
of all zones as well as exceptional maneuverability and the needed 
flexibility for continual surveillance without fuel stops or down time, 
and the ability to deliver post-blast assistance. The area being 
monitored is a high traffic area, surrounded by an urban environment 
where animals are potentially exposed to multiple overflights daily, 
and prior experience has shown that this activity is not anticipated to 
result in take of marine mammals in the area.
    As previously stated, blasting cannot commence until the entire 
Level A Take Zone, Exclusion Zone, and Level B Take Zone are visible to 
monitors, and would not commence in rain, fog, or other adverse weather 
conditions. The visibility below the surface of the water is naturally 
poor, so animals are not anticipated to be seen below the surface. 
However, animals surfacing in these turbid conditions are still 
routinely spotted from the air and from the boats, thus the overall 
observer program is not compromised, only the degree to which animals 
are tracked below the surface. Observers must confirm that all 
protected species are out of the Exclusion Zone and the Level A Take 
Zone for 30 minutes before blasting can commence.
    All observers will be equipped with marine-band VHF radios, maps of 
the blast zone, polarized sunglasses, and appropriate data sheets. 
Communications among observers and with the blaster is critical to the 
success of the watch plan. The aerial observer will be in contact with 
vessel and drill-barge based observers as well as the drill barge crew 
with regular 15-minute radio checks throughout the watch period. 
Constant tracking of animals spotted by any observer will be possible 
due to the amount and type of observer coverage and the communications 
plan. Watch hours will be restricted to between two hours after sunrise 
and one hour before sunset. The watch will begin at least one hour 
prior to the scheduled blast and is continuous throughout the blast. 
Watch continues for at least 30 minutes post blast at which time any 
animals that were seen prior to the blast are visually re-located 
whenever possible and all observers in boats and in the aircraft 
assisted in cleaning up any blast debris.
    If any protected species are spotted during the watch, the observer 
will notify the lead observer, aerial observer, and/or the other 
observers via radio. The animal will be located by the aerial observer 
to determine its range and bearing from the blast pattern. Initial 
locations and all subsequent observations will be plotted on maps. 
Animals within or approaching the Exclusion Zone will be tracked by the 
aerial and boat based observers until they exit the Exclusion Zone. As 
stated earlier, animals that exit the Exclusion Zone and enter the 
Level B Take Zone will also be monitored. The animal's heading shall be 
monitored continuously until it is confirmed beyond the Level B Take 
Zone. Anytime animals are spotted near the Exclusion Zone, the drill 
barge and lead observer will be alerted as to the animal's proximity 
and some indication of any potential delays it might cause.
    If an animal is spotted inside the Exclusion Zone and not re-
observed, no blasting will be authorized until at least 30 minutes has 
elapsed since the last sighting of that animal. The watch will continue 
its countdown up until the T-minus five (5) minute point. At this time, 
the aerial observer will confirm that all animals are outside the 
Exclusion Zone and that all holds have expired prior to clearing the 
drill barge for the T-minus five (5) minute notice. A fish-scare charge 
will be fired at T-minus five (5) minutes and T-minus one (1) minute to 
minimize effects of the blast on fish that may be in the area of the 
blast pattern by scaring them from the blast area.
    An actual postponement in blasting will only occur when a protected 
species is located within or is approaching the Exclusion Zone at the 
point where the blast countdown reaches the T-minus five (5) minutes. 
At that time, if an animal is in or near the Exclusion Zone, the 
countdown will be put on hold until the Exclusion Zone is completely 
clear of protected species and all 30-minute sighting holds have 
expired.
    Within 30 days after completion of all blasting events, the primary 
PSO shall submit a report to the USACE, who will provide it to FWC, 
NMFS and USFWS providing a description of the event, number and 
location of animals seen and what actions were taken when animals were 
seen. Any problems associated with the event and suggestions for 
improvements shall also be documented in the report.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact 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 (50 CFR 216.103). 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 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 harassment, NMFS considers 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 effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    For reasons stated previously in this document, the specified 
activities associated with the USACE's confined blasting activities in 
the East Channel of Big Bend Channel, Tampa Harbor are not likely to 
cause PTS, or other non-

[[Page 11985]]

auditory injury, gastro-intestinal injury, lung injury, serious injury, 
or death to affected marine mammals. As a result, no take by injury, 
serious injury, or death is anticipated or authorized, and the 
potential for temporary or permanent hearing impairment is very low and 
would be minimized through the incorporation of the required monitoring 
and mitigation measures.
    Approximately 244 instances of take to some smaller number of 
Atlantic bottlenose dolphins from the Tampa Bay Stock are anticipated 
to occur in the form of short-term, minor, hearing impairment (TTS) and 
associated behavioral disruption due to the instantaneous duration of 
the confined blasting activities. While some other species of marine 
mammals may occur in the Tampa Harbor, only common bottlenose dolphins 
are anticipated to be potentially impacted by the USACE's confined 
blasting activities.
    For bottlenose dolphins within the proposed action area, there are 
no known designated or important feeding and/or reproductive areas in 
the proposed project area, which consists of a man-made channel with a 
history of maintenance dredging. Many animals perform vital functions, 
such as feeding, resting, traveling, and socializing, on a diel cycle 
(i.e., 24-hour cycle). Behavioral reactions to noise exposure (such as 
disruption of critical life functions, displacement, or avoidance of 
important habitat) are more likely to be significant if they last more 
than one diel cycle or recur on subsequent days (Southall et al., 
2007). Consequently, a behavioral response lasting less than one day 
and not recurring on subsequent days is not considered particularly 
severe unless it could directly affect reproduction or survival 
(Southall et al., 2007). The USACE's proposed confined blasting action 
at the Tampa Harbor, Big Bend Channel's East Channel includes up to two 
planned blasting events per day over multiple days; however, they are 
very short in duration and in a relatively small area surrounding the 
blast holes (compared to the range of the animals) located solely with 
the East Channel, and are only expected to potentially result in 
momentary exposures and reactions by marine mammals in the proposed 
action area, which would not be expected to accumulate in a manner that 
would impact reproduction or survival.
    Atlantic common bottlenose dolphins are the only species of marine 
mammals under NMFS jurisdiction that are likely to occur in the 
proposed action area. They are not listed as threatened or endangered 
under the ESA; however the BSE stocks are considered strategic under 
the MMPA. To reduce impacts on these stocks (and other protected 
species in the proposed action area), the USACE must delay operations 
if animals enter designated zones, and will not conduct blasting if any 
dolphins (or other protected species) are located within the East 
Channel. Due to the nature, degree, and context of the Level B 
harassment anticipated and described in this notice (see ``Potential 
Effects on Marine Mammals and Their Habitat'' section above), the 
activity is not expected to impact rates of recruitment or survival for 
any affected species or stock, particularly given NMFS's and USACE's 
plan to implement mitigation, monitoring, and reporting measures to 
minimize impacts to marine mammals. Also, the confined blasting 
activities are very short in duration and there are no known important 
areas in the USACE's proposed action area. Additionally, the proposed 
confined blasting activities would not adversely impact marine mammal 
habitat.
    As mentioned previously, NMFS estimates that one species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the IHA. The population estimates for the 
marine mammal species that may be taken by Level B harassment is 
estimated to be 564 individuals. To protect these marine mammals in the 
proposed action area, USACE would be required to cease or delay 
confined blasting activities if any marine mammals enters designated 
exclusion zone.
    NMFS has preliminarily determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that the impact of 
conducting the confined blasting activities in the East Channel of the 
Big Bend Channel in the Tampa Harbor may result, at worst, in a 
temporary modification in behavior and/or low-level physiological 
effects (Level B harassment) of common bottlenose dolphins.
    While behavioral modifications, including temporarily vacating the 
area immediately after confined blasting operations, may be made by 
these species to avoid the resultant underwater acoustic disturbance, 
alternate areas are available within this area and the confined 
blasting activities will be instantaneous and sporadic in duration. Due 
to the nature, degree, and context of Level B harassment anticipated, 
the proposed activity is not expected to impact rates of annual 
recruitment or survival of any affected species or stock, particularly 
given the NMFS and applicant's proposal to implement mitigation and 
monitoring measures that would minimize impacts to marine mammals. 
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, NMFS preliminarily finds that the total marine 
mammal take from USACE's proposed confined blasting operations would 
have a negligible impact on the affected marine mammal species or 
stocks.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     No injury is anticipated or authorized;
     Take is limited to Level B harassment, and would be 
expected to be mainly temporary and short-term behavioral disturbance 
and potential for a small number of TTS takes;
     The USACE's proposed confined blasting activities within 
the East Channel includes up to two planned blasting events per day 
over multiple days (up to a maximum of 42 blast events total), but 
these would be very short in duration and in a small area relative to 
the range of the animals; and
     While temporary short-term avoidance of the area may occur 
due to blasting activities, the proposed project area does not 
represent an area of known biological importance such that temporary 
avoidance would constitute an impact to the foraging, socialization, 
and resting activities 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 proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
the affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the

[[Page 11986]]

number of individuals taken to the most appropriate estimation of 
abundance of the relevant species or stock in our determination of 
whether an authorization is limited to small numbers of marine mammals. 
Additionally, other qualitative factors may be considered in the 
analysis, such as the temporal or spatial scale of the activities.
    As noted above, the number of instances of take proposed for 
authorization equates to approximately 43 percent of the estimated 
stock abundance if each instance represents a different individual 
marine mammal. However, as noted above, NMFS anticipates that the 
calculated number of exposures represents some repeated exposures of 
some individuals; in other words, the number of exposures is likely an 
overestimate of individuals. Urian et al. (2009) studied fine-scale 
population structure of bottlenose dolphins in Tampa Bay, and concluded 
that there are five discrete communities (that are not defined as 
separate stocks) of bottlenose dolphins in Tampa Bay. They found 
significant differences in location and association patterns among 
these communities and note that all five communities differed 
significantly in latitude, longitude, or both. Based on the range 
patterns of these discrete communities, only one of these communities, 
Community 5, is expected to occur in the USACE proposed project area. 
The other four communities range farther south of the proposed project 
location. In addition, Community 5 appeared to be the smallest 
community of the five identified communities. Therefore, we conclude 
that the takes associated with the USACE proposed confined blasting 
actually represents no more than 20 percent of the total Tampa Bay 
stock of bottlenose dolphins.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
preliminarily 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)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally, in this case with the NMFS Southeast Region 
(SERO) Protected Resources Division Office, whenever we propose to 
authorize take for endangered or threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to USACE for conducting confined blasting activities 
within the East Channel of the Big Bend Channel, located in the Tampa 
Harbor, Hillsborough Bay (part of Tampa Bay). The proposed IHA will be 
valid from April 1, 201 through March 31, 2020, but blasting activities 
shall only occur April 1 through October 31 annually, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. This section contains a draft of the IHA itself. The 
wording contained in this section is proposed for inclusion in the IHA 
(if issued):
    U.S. Army Corps of Engineers, Jacksonville District, P.O. Box 4970, 
Jacksonville, Florida (FL) 32232, is hereby authorized under section 
101(a)(5)(D) of the Marine Mammal Protection Act (MMPA) (16 U.S.C. 
1371(a)(5)(D)), to harass small numbers of marine mammals incidental to 
blasting operations in the East Channel of the Big Bend Channel as part 
of the Tampa Harbor Big Bend Channel Expansion Project in Hillsborough 
Bay (part of Tampa Bay) in Hillsborough County, Florida:
    1. This Authorization is valid from April 1, 2019, through March 
31, 2020, but blasting may occur only between April 1 and October 31, 
annually unless the U.S. Fish and Wildlife Service (USFWS) grants an 
extension of the blasting period.
    2. This Authorization is valid only for the U.S. Army Corps of 
Engineers (USACE) activities associated with the blasting within the 
East Channel of the Big Bend Channel in the Tampa Harbor in 
Hillsborough County, Florida.
    3. Species Authorized and Level of Takes
    (a) The incidental taking of marine mammals, by Level B harassment 
only, is limited to the following species in the waters of Hillsborough 
Bay (part of Tampa Bay) and the Atlantic Ocean:
    (i) Odontocetes--244 takes from the Tampa Bay Stock of Atlantic 
bottlenose dolphin (Tursiops truncatus).
    (ii) If any marine mammal species under NMFS jurisdiction other 
than bottlenose dolphin are encountered during blasting operations and 
are likely to be exposed to sound thresholds equal to or greater than 
Level B harassment, then the Holder of this Authorization must delay or 
suspend blasting operations to avoid take.
    (b) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in Condition 3(a) above or the 
taking of any kind of any other species of marine mammal is prohibited 
and may result in the modification, suspension or revocation of this 
Authorization.
    4. The methods authorized for taking by Level B harassment are 
limited to explosives with a maximum charge weight per delay of 40 lb 
(18.1 kg).
    5. The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported immediately to the Office of 
Protected Resources, National Marine Fisheries Service (NMFS), at 301-
427-8401.
    6. Mitigation and Monitoring Requirements
    The Holder of this Authorization is required to implement the 
following mitigation and monitoring requirements when conducting the 
specified activities to achieve the least practicable impact on 
affected marine mammal species or stocks:
    (a) The USACE must ensure that the Florida Fish and Wildlife 
Conservation Commission (FWC), the U.S. Fish and Wildlife Service 
(USFWS), and NMFS (Headquarters Protected Resources Division and SERO 
Protected Resources) are provided the contractor's approved blasting 
plan for review prior to any blasting activities. This blasting 
proposal must include information concerning a watch program and 
details of the blasting events. This information must be submitted at 
least 30 days prior to the proposed date of the blast(s) to the 
following addresses:
    (i) FWC-ISM, 620 South Meridian Street, Mail Stop 6A, Tallahassee, 
FL 32399-1600 or [email protected] and Dr. Allen Foley 
[email protected].

[[Page 11987]]

    (ii) NMFS Office of Protected Resources, 1315 East West Highway, 
Silver Spring, MD 20910.
    (iii) NMFS Southeast Regional Office (SERO), Protected Species 
Management Branch, 263 13th Avenue South, St. Petersburg, FL 33701, and
    (iv) USFWS, 1339 20th Street, Vero Beach, FL 32960-3559.
    (b) The contractor's blasting plan shall include at least the 
following information:
    (i) A list of Protected Species Observers (PSOs), their 
qualifications, and positions for the watch, including a map depicting 
the proposed locations for boat or land-based PSOs. NMFS-qualified PSOs 
must have prior on-the-job experience observing for marine mammals and 
other protected species during previous in-water blasting events where 
the blasting activities were similar in nature to the blasting project 
in the Tampa Harbor.
    (ii) The amount of explosive charge proposed, the explosive 
charge's equivalency in TNT, how it will be executed (depth of 
drilling, stemming, in-water, etc.), a drawing depicting the placement 
of the charges, size of the exclusion zone, and how it will be marked 
(also depicted on a map), tide tables for the blasting event(s), and 
estimates of times and days for blasting events (with an understanding 
this is an estimate, and may change due to weather, equipment, etc.).
    (c) The USACE shall notify SERO (Ms. Laura Engleby, Marine Mammal 
Branch Chief, [email protected]) and FWC (Dr. 
Allen Foley, [email protected]) at the initiation and completion of 
all in-water blasting.
    (d) A test blast program shall be completed prior to implementing a 
construction blasting program. The test blast program shall have all 
the same monitoring and mitigation measures in place for marine mammals 
and other protected species (see below).
    (e) The weight of explosives to be used in each blast shall be 
limited to the lowest poundage of explosives that can adequately break 
the rock.
    (f) The explosives shall be confined in a hole with drill patterns 
(i.e., holes in the pattern) that are restricted to a minimum of 8 ft 
(2.4 m) separation from a loaded hole.
    (g) The hours of blasting shall be restricted from two hours after 
sunrise to one hour before sunset to ensure adequate observation of 
marine mammals in the project area.
    (h) Select explosive products and their practical application 
method to address vibration and air blast (overpressure) control for 
protection of existing structures and marine wildlife.
    (i) Loaded blast holes shall be individually delayed to reduce the 
maximum lbs per delay at point detonation (in order to spread the 
explosive's total pressure over time), which in turn will reduce the 
mortality radius. Delay timing adjustments with a minimum of eight 
milliseconds (ms) between delay detonations to stagger the blast 
pressures and prevent cumulative addition of pressures in the water.
    (j) The USACE shall require the contractor to cap the hole 
containing explosives with rock in order to spread the explosive's 
outward potential of the blast and total overpressure over time, 
thereby reducing the chance of injuring a marine mammal or other 
protected species.
    (k) The blast design shall match, to the extent possible, the 
energy needed in the ``work effort'' of the borehole to the rock mass 
to minimize excess energy vented into the water column or hydraulic 
shock.
    (l) Due to USFWS requirements, blasting operations shall not occur 
during the period from November 1 through March 31 (due to the 
increased likelihood of manatees (Trichechus manatus latirostris) being 
present within the project area).
    (m) Calculate, establish, and monitor a Level A Take Zone (equal to 
the PTS injury zone), Exclusion (i.e., the Level A Take Zone plus 500 
ft [152.4 m], and a Level B Take Zone (extending from the Exclusion 
Zone to the Level B Take Zone radius). All of the zones shall be noted 
by buoys for each of the blasts.
    (n) The watch program shall begin at least one hour prior to the 
scheduled start of blasting to identify the possible presence of marine 
mammals and is continuous throughout the blast. The watch program shall 
continue for at least 30 minutes after detonations are complete.
    (o) The watch program shall consist of a minimum of six NMFS-
qualified PSOs (at least one aerial-based PSO, two boat-based PSOs, two 
drill barge-based PSOs, and one PSO placed in the most optimal 
observation location on a day-by-day basis depending on the location of 
the blast and the placement of dredging equipment). NMFS-qualified PSOs 
must be approved in advance by NMFS's Office of Protected Resources, to 
record the effects of the blasting and dredging activities and the 
resulting noise on marine mammals. Each PSO shall be equipped with a 
two-way marine-band VHF radio that shall be dedicated exclusively to 
the watch. Extra radios shall be available in case of failures. All of 
the PSOs shall be in close communication with the blasting sub-
contractor in order to half the blast event if the need arises. If all 
PSOs do not have working radios and cannot contact the primary PSO and 
the blasting sub-contractor during the pre-blast watch, the blast shall 
be postponed until all PSOs are in radio contact. PSOs shall be 
equipped with polarized sunglasses, binoculars, a red flag for back-up 
visual communication, and appropriate data sheets (i.e., a sighting log 
with a map) to record sightings and other pertinent data. All blasting 
events are weather dependent and conditions must be suitable for 
optimal viewing conditions to be determined by the PSOs.
    (p) The watch program shall include a continuous aerial survey to 
be conducted by aircraft, as approved by the Federal Aviation 
Administration. The aerial-based PSO is in contact with vessel and 
drill barge-based PSOs and the drill barge with regular 15-minute radio 
checks through the watch period. The aerial PSO shall fly in a turbine 
engine helicopter with the doors removed to provide maximum visibility 
of the zones.
    (q) Boat-based PSOs shall be placed on one of two vessels, both of 
which have attached platforms that place the PSOs eyes at least 10 ft 
(3 m) above the water surface enabling optimal visibility of the water 
from the vessels. The boat-based PSOs cover the Exclusion Zone and 
Level B Take Zone where waters are deep enough to safely operate.
    (r) If any marine mammals are spotted during the watch, the PSO 
shall notify the aerial-based PSO and/or other PSOs via radio. The 
animal(s) shall be located by the aerial-based PSO to determine its 
range and bearing from the blast pattern. Initial locations and all 
subsequent re-acquisitions shall be plotted on maps. Animals within or 
approaching the Exclusion Zone are tracked by the aerial and boat-based 
PSOs until they have exited the Exclusion Zone, the drill barge shall 
be alerted as to the animal's proximity and some indication of any 
potential delays it might cause.
    (s) If any animal(s) is sighted inside the Exclusion Zone or Level 
A Take Zone and not re-acquired, no blasting is authorized until at 
least 30 minutes has elapsed since the last sighting of that animal(s). 
The PSOs on watch shall continue the countdown up until the T-minus 
five minutes point. At this time, the aerial-based PSO confirms that 
all animals are outside the Exclusion Zone and Level A Take Zone and 
that all holds have expired prior to clearing the drill barge for the 
T-minus five minutes notice.
    (t) The blasting event shall be halted immediately upon request of 
any of the PSOs. An ``all clear'' signal must be

[[Page 11988]]

obtained from the aerial PSO before the detonation can occur.
    (u) If animals are sighted, the blast event shall not take place 
until the animal moves out of the Exclusion Zone under its own 
volition. Animals shall not be herded away or harassed into leaving. 
Specifically, the animals must not be intentionally approached by 
project watercraft. Blasting may only commence when 30 minutes has 
passed without an animal being sighted within, or approaching, the 
Exclusion Zone or Level A Take Zone.
    (v) After the blast, any animal(s) seen prior to the blast are 
visually relocated whenever possible.
    (w) The PSOs and contractors shall evaluate any problems 
encountered during blasting events and logistical solutions shall be 
presented to the Contracting Officer. Corrections to the watch shall be 
made prior to the next blasting event. If any one of the aforementioned 
conditions is not met prior to or during the blasting, the watch PSOs 
shall have the authority to terminate the blasting event. If any one of 
the aforementioned conditions is not met prior to or during the 
blasting, the watch PSOs shall have the authority to terminate the 
blasting event, until resolution can be reached with the Contracting 
Officer.
    (x) A fish-scare charge shall be fired at T-minus five minutes and 
T-minus one minute to minimize effects of the blast on fish that may be 
in the same area of the blast pattern by scaring them from the blast 
area.
    (y) The Contractor shall use hydrophones to record the SEL and SPL 
associated with up to 42 confined blasting events. The Contractor shall 
also record the associated work (including borehole drilling and fish 
scare charges) as separate recordings. The Contractor shall provide 
nearby hydrophone records of drilling operation of 30 minutes over 
three early contract periods at least 18 hours apart. The Contractor 
shall provide hydrophone or transducer records within the contract area 
of three 10-minute quiet periods (not necessarily continuous) over 
three early contract periods at least 18 hours apart or prior to the 
contractor's full mobilization to the site, and 10 close-approaches of 
varied vessel sizes. Information to be provided as both an Excel file 
and recording for each hydrophone (.wav file) shall include:
     GPS location of the hydrophone aboard the vessel. The 
hydrophone shall be located outside of the range that would cause 
clipping (overloading of the hydrophone, causing the absolute peaks to 
be lost).
     Water depth to the sediment/rock bottom. The hydrophone 
shall be placed at the shallower of 3 m (9.84 ft, or 9 ft, 10 inches) 
depth or the mid-water column depth.
     Information provided by the Blasting Contractor regarding 
the blast pattern or drilling. The minimum data shall include, as 
appropriate for blast shots or drilling; the date, time and blast 
number of the shot; the average water depth of the shot pattern or the 
average depth to sediment/rock at the nearest five shot holes closest 
to the hydrophone location; GPS location of the closest shot hole in 
the blast pattern to the hydrophone; the maximum charge weight per 
delay of the shot pattern in pounds of explosives; and the largest 
charge weight per delay of the closest delay sequence to the 
hydrophone.
    7. Reporting Requirements
    The Holder of this Authorization is required to:
    (a) Submit a draft report on all activities and monitoring results 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, within 90 days after completion of the 
demolition and removal activities. This report must contain and 
summarize the following information:
    (i) Dates, times, locations, weather, sea conditions during all 
blasting activities and marine mammal sightings;
    (ii) Species, number, location, distance, and behavior of any 
marine mammals, as well as associated blasting activities, observed 
before, during, and after blasting activities.
    (iii) An estimate of the number (by species) of marine mammals that 
may have been taken by Level B harassment during the blasting 
activities with a discussion of the nature of the probably consequences 
of that exposure on the individuals that have been exposed. Describe 
any behavioral responses or modifications of behaviors that may be 
attributed to the blasting activities.
    (iv) A description of the implementation and effectiveness of the 
monitoring and mitigation measures of the Incidental Harassment 
Authorization as well as any additional conservation recommendations.
    (b) Submit a final report to the Chief, Permits and Conservation 
Division, Office of Protected Resources, NMFS, within 30 days after 
receiving comments from NMFS on the draft report. If NMFS decides that 
the draft report needs no comments, the draft report shall be 
considered to be the final report.
    (c) 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, serious injury or mortality, USACE shall immediately 
cease the specified activities and immediately report the incident to 
the Chief of the Permits and Conservation, Office of Protected 
Resources and the NMFS Southeast Region Marine Mammal Stranding 
Network. The report must include the following information:
    (i) Time, date, and location (latitude/longitude) of the incident; 
description of the incident; status of all noise-generating source use 
in the 24 hours preceding the incident; water depth; environmental 
conditions (e.g., wind speed and direction, Beaufort sea state, cloud 
cover, and visibility); description of all marine mammal observations 
in the 24 hours preceding the incident; species identification or 
description of the animal(s) involved; fate of the animal(s); and 
photographs or video footage of the animal(s) (if equipment is 
available).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with USACE to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. USACE may not resume their 
activities until notified by NMFS via letter or email, or telephone.
    In the event that USACE discovers an injured or dead marine mammal, 
and the lead PSO determines that the cause of the injury or death is 
unknown and the death is relatively recent (i.e., in less than a 
moderate state of decomposition as described in the next paragraph), 
USACE shall immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources and the NMFS 
Southeast Region Marine Mammal Stranding Network. The report must 
include the same information identified in the paragraph above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS will work with USACE to determine whether modifications 
in the activities are appropriate.
    In the event that USACE discovers an injured or dead marine mammal, 
and the lead PSO determines that the injury or death is not associated 
with or related to the activities authorized in the IHA (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), USACE shall report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources and the NMFS Southeast Region Marine Mammal Stranding Network 
within 24 hours of discovery. USACE shall provide photographs or video 
footage (if

[[Page 11989]]

available) or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network.
    8. To the greatest extent feasible, USACE is encouraged to 
coordinate its monitoring studies on the distribution and abundance of 
marine mammals in the project area with the NMFS's Southeast Fisheries 
Science Center, USFWS, and any other state or Federal agency conducting 
research on marine mammals. Also, report to NMFS and USFWS any chance 
observations of marked or tag-bearing marine mammals or carcasses, as 
well as any rare or unusual species of marine mammals.
    9. A copy of this Authorization must be in the possession of all 
contractors and PSOs operating under the authority of this Incidental 
Harassment Authorization.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
confined blasting activities within the East Channel of the Big Bend 
Channel, Tampa Harbor. Please include with your comments any supporting 
data or literature citations to help inform our final decision on the 
request for MMPA authorization.

    Dated: March 14, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-05504 Filed 3-16-18; 8:45 am]
 BILLING CODE 3510-22-P