[Federal Register Volume 83, Number 87 (Friday, May 4, 2018)]
[Notices]
[Pages 19701-19710]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-09499]


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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; issuance of Incidental Harassment Authorization (IHA).

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA), as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the U.S. Army Corps of Engineers, Jacksonville District, (USACE) for 
authorization to take one species of marine mammal incidental to 
confined blasting in the East Channel of the Big Bend Channel in Tampa 
Harbor, Tampa, Florida.

DATES: The IHA will be valid from April 1, 2019 through March 31, 2020.

FOR FURTHER INFORMATION CONTACT: Dale Youngkin, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the IHA 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:

[[Page 19702]]

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 adopted the USACE's Supplemental Environmental 
Assessment (EA) (August, 2017). After independent evaluation of the 
document and review of comments submitted in response to the proposed 
IHA notice, NMFS has concluded that the USACE's EA includes adequate 
information analyzing the effects on the human environment of issuing 
the IHA and issued our ow Finding of No Significant Impact (FONSI). 
NMFS' FONSI is available for review on our website at http://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.

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

    A detailed description of the planned USACE project is provided in 
the Federal Register notice for the proposed IHA (83 FR 11968; March 
19, 2018). Since that time, no changes have been made to the planned 
activities. Therefore, we provide only a summary here. Please refer to 
the Federal Register Notice for the full description of the specified 
activity.
    USACE plans to conduct confined underwater blasting within the East 
Channel as part of the Tampa Harbor Big Bend Channel Expansion Project 
in Tampa, FL. The purpose of the confined underwater blasting is to 
break up rock in the existing East Channel to allow for dredging 
necessary to widen and deepen the existing channel.
    Due to coordination with the U.S. Fish and Wildlife Service (USFWS) 
to avoid potential impacts to manatees, the USACE will be restricted to 
the months of April-October for blasting activities. In addition to the 
seasonal restriction for blasting activities, the USACE has proposed 
restricting the number of blasting events to a maximum of 42 events, 
and the maximum weight of each charge will be 18 kg (40 lbs)/charge, 
for a total of 725 kg (1,600 lbs) per each blasting event.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see ``Proposed 
Mitigation'' and ``Proposed Monitoring and Reporting'').

Comments and Responses

    A notice of NMFS's proposal to issue an IHA to the USACE was 
published in the Federal Register on March 19, 2018 (83 FR 11968). That 
notice described the USACE's activity, the marine mammal species that 
may be affected by the activity, and the anticipated effects on marine 
mammals. During the 30-day public comment period, NMFS received one 
comment letter from the Marine Mammal Commission (Commission). The 
Commission concurred with NMFS' preliminary findings and recommended 
that NMFS issue the IHA, subject to the inclusion of the proposed 
mitigation, monitoring, and reporting measures as provided in the 
notice of the proposed IHA.
    Comment 1: The Commission recommended that NMFS enumerate the 
number of bottlenose dolphins that could be taken during the planned 
activities by applying standard rounding rules before summing the 
numbers of estimated takes across days of activities.
    Response: Calculating predicted take is not an exact science and 
there are arguments for taking different mathematical approaches in 
different situations, and for making qualitative adjustments in other 
situations. NMFS is currently engaged in developing a protocol to guide 
more consistent take calculation given certain circumstances. We 
believe, however, that the methodology for this action remains 
appropriate and the the low likelihood of take in combination with 
implementation of monitoring and mitigation measures will avoid any 
take of marine mammals by Level A harassment.
    Comment 2: The Commission recommended several items for NMFS to 
ensure are incorporated into either the final hydroacoustic monitoring 
plan or the IHA itself. In addition, the Commission stated these items 
would likely need to be stipulated by the USACE in its hydroacoustic 
monitoring contract.
    Response: NMFS coordinated with the USACE in regard to the 
hydroacoustic monitoring plan. As stated in the MMC comment, USACE has 
indicated that they would need to have a contractor on board prior to 
development of the hydroacoustic monitoring plan. USACE agreed to 
develop the hydroacoustic monitoring

[[Page 19703]]

plan in coordination with NMFS, and agreed to provide NMFS with a draft 
plan for review at least 30 days prior to beginning the blasting 
activities. However, the information provided by the MMC was shared 
with USACE and NMFS will require this information to be included in 
hydroacoustic monitoring plan prior to approval of the plan and has 
incorporated this information into the IHA itself.

Description of Marine Mammals in the Area of Specified Activities

    A detailed description of the species likely to be affected by the 
USACE confined blasting project, including brief introductions to the 
species and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, are provided in USACE's application and the Federal 
Register notice for the proposed IHA (83 FR 11968; March 19, 2018). We 
are not aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
the Federal Register notice for these descriptions. Table 1 lists all 
marine mammal species with potential occurrence in the project area; 
however, only bottlenose dolphin (Tursiops truncatus) have the 
potential to be affected by the USACE proposed activities, so other 
species are not discussed further in this document. Please also refer 
to additional species information available in the NMFS Atlantic Ocean 
Stock Assessment Reports (SARs) s at http://nmfs.noaa.gov/pr/sars/region.htm.

                                          Table 1--Marine Mammals With Potential Occurrence in the Project Area
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                                                           Occurrence in  project     Stock population      ESA  status     MMPA status
             Species                      Habitat                   area                estimate \1\            \2\             \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 East  NL              NC                          14
 acutorostrata).                                                                     Coast Stock.
Bryde's whale (Balaenoptera        Pelagic and coastal.  Rare.....................  33--Northern Gulf of  NL              S                         0.03
 brydei).                                                                            Mexico Stock.
Sei whale (Balaenoptera borealis)  Primarily offshore,   Rare.....................  357--Nova Scotia      EN              S                          0.5
                                    pelagic.                                         Stock.
Fin whale (Balaenoptera physalus)  Slope, mostly         Rare.....................  1,618--Western North  EN              S                          2.5
                                    pelagic.                                         Atlantic Stock.
Blue whale (Balaenoptera           Pelagic and coastal.  Rare.....................  440--Western North    EN              S                          0.9
 musculus).                                                                          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 (Mesoplodon  Pelagic, slope and    Rare.....................  149--Northern Gulf    NL              NC                         0.8
 europaeus).                        canyons.                                         of Mexico Stock.
Sowerby's beaked whale             Pelagic, slope and    Rare.....................  7,092--Western North  NL              NC                         0.8
 (Mesoplodon bidens).               canyons.                                         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 of  NL              NC                         0.4
 cavirostris).                      canyons.                                         Mexico Stock.
Killer whale (Orcinus orca)......  Widely distributed..  Rare.....................  28--Northern Gulf of  NL              NC                         0.1
                                                                                     Mexico Stock.
Short-finned pilot whale           Inshore and offshore  Rare.....................  2,415--Northern Gulf  NL              NC                          15
 (Globicephala macrorhynchus).                                                       of Mexico Stock.
False killer whale (Pseudorca      Pelagic.............  Rare.....................  NA--Northern Gulf of  NL              NC                     Unknown
 crassidens).                                                                        Mexico Stock.
Melon-headed whale (Peponocephala  Pelagic.............  Rare.....................  2,335--Northern Gulf  NL              NC                          13
 electra).                                                                           of Mexico Stock.
Pygmy killer whale (Feresa         Pelagic.............  Rare.....................  152--Northern Gulf    NL              NC                         0.8
 attenuata).                                                                         of Mexico Stock.
Risso's dolphin (Grampus griseus)  Pelagic, shelf......  Rare.....................  2,442--Northern Gulf  NL              NC                          16
                                                                                     of Mexico Stock.
Common bottlenose dolphin          Offshore, inshore,    Common...................  564--Tampa Bay Stock  NL              S                      Unknown
 (Tursiops truncatus).              coastal, and                                     \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 of  NL              NC                     Unknown
 hosei).                                                                             Mexico Stock.
Striped dolphin (Stenella          Coastal, shelf and    Rare.....................  1,849--Northern Gulf  NL              NC                          10
 coeruleoalba).                     slope.                                           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 of  NL              NC                     Unknown
 (Stenella frontalis).                                                               Mexico Stock.
Spinner dolphin (Stenella          Mostly pelagic......  Uncommon.................  11,441--Northern      NL              NC                          62
 longirostris).                                                                      Gulf of Mexico
                                                                                     Stock.

[[Page 19704]]

 
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, and  Uncommon.................  6,620--Florida Stock  T               D               ..............
 manatee) (Trichechus manatus       estuaries.                                       \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).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The Federal Register notice for the proposed IHA (83 FR 11968; 
March 19, 2018) included a discussion of the effects of disturbance on 
marine mammals and their habitat; therefore, that information is 
summarized here. Please refer to the proposed IHA Federal Register 
notice for more detailed information.
    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.
    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). Implementation of mitigation and monitoring 
efforts will avoid mortality, serious injury, and Level A harassment 
(PTS). Therefore, only Level B harassment (TTS and behavioral 
harassment) are anticipated due to the USACE confined underwater 
blasting activities.
    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. 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, 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.

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.
    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: http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

[[Page 19705]]



                            Table 2--NMFS' Current Thresholds and Criteria for Impact Analysis From the Use of Explosives for
                                                                 Mid-Frequency Cetaceans
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                                                                                                   GI
         Hearing group                 Species         Behavioral        TTS           PTS        tract         Lung injury              Mortality
                                                                                                 injury
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans........  Most delphinids,    165 dB SELcum  170 dB        185 dB          237 dB  39.1 M1/3 (1 + [DRm/    91.4 M1/3 (1 + [DRm/
                                  medium and large                   SELcum; 224   SELcum; 230             10.081])1 / 2 Pa-sec    10.081])1 / 2 Pa-sec
                                  toothed whales.                    dB PK.        dB PK.                  Where: M = mass of      Where: M = mass of
                                                                                                           the animals in kg DRm   the animals in kg DRm
                                                                                                           = depth of the          = depth of the
                                                                                                           receiver (animal) in    receiver (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. The Level A (PTS) harassment zone was calculated to be 0.14 
square kilometers based on an isopleth of 378 m; the Level B TTS 
harassment zone was calculated to be 2.85 square kilometers based on an 
isopleth of 2,125 m; and the Level B behavioral harassment zone was 
calculated to be 6 square kilometers based on an isopleth of 3,780 m.
    We note here that Level A take is not anticipated due to the small 
Level A harassment zone and density of bottlenose dolphins in the 
proposed project area resulting in a low likelihood of Level A take for 
any one blasting event combined with mitigation measures to avoid Level 
A take.

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 state 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 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,

[[Page 19706]]

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.

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.
    [ssquf] Hydroacoustic monitoring will be performed for each blast 
event, up to the maximum of 42 blast events. A hydroacoustic monitoring 
plan will be developed in coordination with NMFS HQ Permits and 
Conservation Division, and will be submitted to NMFS for review at 
least 30 days prior to commencement of the blasting activities. As part 
of this hydroacoustic monitoring, the contractor shall:
    [cir] Describe hydroacoustic measurement methods. The sampling rate 
of the recording devices (i.e., hydrophone and/or pressure transducer) 
shall be specified to ensure the necessary frequencies (10 Hz-40 kHz) 
and pressure signals (at least 1 MHz) are recorded and the appropriate 
filter (band pass) is used. The type of hydrophone proposed for use 
shall also be described and shall be appropriate for collecting 
measurements of underwater detonations as well as ambient measurements 
in the far field (i.e., low vs high sensitivity). The plan shall 
specify that recording devices shall be placed in the near field (at 10 
m) and sufficiently in the far field (and away from shipping lanes) to 
collect the relevant data.
    [cir] Describe analytical methods. The plan shall specify that 
pressure signals must be analyzed using appropriate signal processing 
methods and applicable equations. The various impulse metrics will be 
calculated using time series data. Cumulative sound exposure levels 
(SELcum) will be calculated using a linear summation of 
acoustic intensity. Weighted cumulative sound exposure thresholds will 
be used to estimate the various ranges.

[[Page 19707]]

    The hydroacoustic monitoring plan shall stipulate that the 
contractor will:
    [cir] Record the SEL and SPL associated with each blasting event;
    [cir] Record the associated work (including borehole drilling and 
fish scare charges) as separate recordings;
    [cir] Provide nearby hydrophone records of drilling operations of 
30 minutes over three early contract periods at least 18 hours apart.
    [cir] Provide hydrophone or transducer records within the contract 
area of three continuous 10-minute quiet periods (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. This information will be provided as both an Excel file and 
recording for each hydrophone (.wav file) shall include: GPS location 
of the hydrophone (to be located outside of the range that would cause 
clipping); Water depth to the sediment/rock bottom (to be placed at the 
shallower of 9.84 ft (3 m) depth of the mid-water column depth); and 
Information regarding the blast pattern or drilling.
    [cir] Provide a report that includes the appropriate metrics (i.e., 
impulse in Pa-sec or psi-msec; peak sound levels; and SELcum 
for the entire blast event); appropriate statistics (i.e., median, 
mean, minimum, and maximum); and relevant information (i.e., number of 
delays per blast event, total net explosive weight of each blast event, 
sediment characteristics/types, hydrophone depths and distances to the 
closest and farthest delay, water depth, power specral data).
     In addition to review of the blasting plan, NMFS's 
Southeast Region Office and local stranding network 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 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 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 determined that the proposed

[[Page 19708]]

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.

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 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 60 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.

[[Page 19709]]

    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-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 as well as the 
Proposed IHA notice (see ``Potential Effects on Marine Mammals and 
Their Habitat'' section above and in 83 FR 11968, March 19, 2018)), 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 are be required to cease or delay confined 
blasting activities if any marine mammals enters designated exclusion 
zone.
    NMFS has 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

[[Page 19710]]

expected to impact rates of annual recruitment or survival of any 
affected species or stock, particularly given the NMFS and applicant's 
plan 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 
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 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 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 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 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.

Authorization

    NMFS has issued an IHA to the USACE to take one species of marine 
mammal incidental to confined blasting in the East Channel of the Big 
Bend Channel in Tampa Harbor, Tampa, Florida provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated.

    Dated: May 1, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-09499 Filed 5-3-18; 8:45 am]
 BILLING CODE 3510-22-P