Takes of Marine Mammals During Specified Activities; Blasting Operations by the U.S. Army Corps of Engineers During the Port of Miami Construction Project in Miami, FL, 71517-71535 [2011-29886]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 223 (Friday, November 18, 2011)]
[Notices]
[Pages 71517-71535]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-29886]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA628


Takes of Marine Mammals During Specified Activities; Blasting 
Operations by the U.S. Army Corps of Engineers During the Port of Miami 
Construction Project in Miami, FL

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 an application from the U.S. Army Corps of 
Engineers (ACOE) for an Incidental Harassment Authorization (IHA) to 
take small numbers of marine mammals, by harassment, incidental to 
blasting operations in the Port of Miami in Miami, Florida. NMFS has 
reviewed the application, including all supporting documents, and 
determined that it is adequate and complete. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to ACOE to incidentally harass, by Level B 
harassment only, marine mammals during the specified activity.

DATES: Comments and information must be received no later than December 
19, 2011.

ADDRESSES: Comments on the application should be addressed to P. 
Michael Payne, Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910. The mailbox address for providing 
email comments is ITP.Goldstein@noaa.gov. NMFS is not responsible for 
email comments sent to addresses other than the one provided here. 
Comments sent via email, including all attachments, must not exceed a 
10-megabyte file size.
    All comments received are a part of the public record and will 
generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications without change. All Personal Identifying 
Information (for example, name, address, etc.) voluntarily submitted by 
the commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the contact listed here (see FOR FURTHER INFORMATION 
CONTACT) or visiting the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    This project was previously evaluated by the ACOE under an 
Environmental Impact Statement (EIS) and a Record of Decision (ROD) for 
the proposed project was signed on May 22, 2006, which is also 
available at the same Internet address. Documents cited in this notice 
may be viewed, by appointment, during regular business hours, at the 
aforementioned address.

FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Jolie Harrison, 
Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1361(a)(5)(D)) directs 
the Secretary of Commerce (Secretary) to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals of a species or population stock, by United States citizens who 
engage in a specified activity (other than commercial fishing) within a 
specified geographical region if certain findings are made and, if the 
taking is limited to harassment, a notice of a proposed authorization 
is provided to the public for review.
    Authorization for the incidental taking of small numbers of marine 
mammals shall be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s), and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and requirements pertaining to the mitigation, monitoring and 
reporting of such takings. 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.''

[[Page 71518]]

    Section 101(a)(5)(D) of the MMPA establishes a 45-day time limit 
for NMFS's review of an application followed by a 30-day public notice 
and comment period on any proposed authorizations for the incidental 
harassment of small number of marine mammals. Within 45 days of the 
close of the public comment period, NMFS must either issue or deny the 
authorization.
    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).

Summary of Request

    On May 17, 2011, NMFS received a letter from the ACOE, requesting 
an IHA. The requested IHA would authorize the take, by Level B 
(behavioral) harassment, of small numbers of Atlantic bottlenose 
dolphins (Tursiops truncatus) incidental to blasting operations in the 
Miami Harbor, Port of Miami, in Miami-Dade County, Florida. The IHA 
application was considered adequate and complete on September 9, 2011. 
The ACOE proposes to conduct four components as part of the project in 
Miami Harbor. These components are:
    (1) The widening of Cut 1 and deepening of Cut 1 and Cut 2;
    (2) Adding a turn widener and deepening at the southern 
intersection of Cut 3 within Fisherman's Channel;
    (3) Widening and deepening the Fisher Island Turning Basin; and
    (4) Expanding the Federal Channel and Port of Miami berthing areas 
in Fisherman's Channel and the Lummus Island Turning Basin.
    The construction will likely be completed using a combination of 
mechanical dredge (i.e., a clamshell or backhoe), cutterhead dredge, 
and rock pre-treatment by confined blasting. The dredging will remove 
approximately 5,000,000 cubic yards (3,822,774.3 cubic meters [m\3\]) 
of material from the harbor. Material removed from the dredging will be 
placed in Miami Harbor Ocean Dredged Material Disposal Site, or used to 
construct seagrass and reef mitigation projects.
    The blasting is proposed to take place beginning during the summer 
of 2012 (June, 2012), and is expected to take up to 24 months in Miami, 
Florida. Additional information on the construction project is 
contained in the application, which is available upon request (see 
ADDRESSES).

Description of the Proposed Specified Activities

    The ACOE proposes to deepen and widen the Federal channels at Miami 
Harbor, Port of Miami, in Miami-Dade County, Florida. The recommended 
plan (Alternative 2 of the Environmental Impact Statement [EIS]) 
includes four components:
    (1) Widen the seaward portion of Cut 1 from 500 to 800 feet (ft) 
(152.4 to 243.8 meters [m]) and deepen Cut 1 and Cut 2 from a project 
depth of -44 to -52 ft (13.4 to 15.9 m);
    (2) Add a turn widener at the southern intersection of Cut 3 within 
Fisherman's Channel and deepen to a project depth of -50 ft (-15.2 m);
    (3) Increase the Fisher Island Turning Basin from 1,200 to 1,500 ft 
(365.8 to 457.2 m), truncate the northeast section of the turning basin 
to minimize seagrass impacts, and deepen from -42 ft (-12.8 m) to a 
project depth of -50 ft; and
    (4) The Federal Channel and Port of Miami berthing areas in 
Fisherman's Channel and in the eastern end of the Lummus Island Turning 
Basin (LITB) will be expanded by 60 ft (18.3 m) to the south for a 
total of a 160 ft (48.8 m) wide berthing area and will be deepened from 
-42 ft to a project depth of -50 ft. The Federal Channel will be 
widened 40 ft (12.2 m) to the south, for a 100 ft (30.5 m) total width 
increase in Fisherman's Channel. Component 5 will deepen Fisherman's 
Channel and the LITB from -42 ft to a project depth of -50 ft. See 
Figure 1 of ACOE's IHA application for a map of the proposed project's 
components.
    Disposal of the estimated five million cubic yards of dredged 
material would occur at up to three disposal sites (seagrass mitigation 
area, offshore artificial reef mitigation areas, and the Miami Offshore 
Dredged Material Disposal Site). This project was previously evaluated 
under an Environmental Impact Statement (EIS) titled ``Miami Harbor 
Miami-Dade County, Florida Navigation Study, Final General Reevaluation 
Report and Environmental Impact Statement,'' prepared under the 
National Environmental Policy Act, and a Record of Decision for the 
proposed project was signed on May 22, 2006. The original proposed 
project included six components, two of which (four and six) have been 
removed. The EIS provides a detailed explanation of project location as 
well as all aspects of project implementation. It is also available 
online for public review at: https://www.saj.usace.army.mil/Divisions/Planning/Branches/Environmental/DOCS/OnLine/Dade/MiamiHarbor/NAV_STUDY_VOL-1_MIAMI.pdf.
    To achieve the deepening of the Miami Harbor from the existing 
depth of -45 ft (-13.7 m) to project depth of -52 ft, pretreatment of 
some of the rock areas may be required using confined underwater 
blasting, where standard construction methods are unsuccessful due to 
the hardness of the rock. The ACOE has used two criteria to determine 
which areas are most likely to need blasting for the Miami Harbor 
expansion: (1) Areas documented by core borings to contain hard and/or 
massive rock; and (2) areas previously blasted in the harbor during the 
2005 blasting and dredging project.
    The duration of the blasting is dependent upon a number of factors 
including hardness of rock, how close the drill holes are placed, and 
the type of dredging equipment that will be used to remove the 
pretreated rock. Without this information, an exact estimate of how 
many ``blast days'' will be required for the project cannot be 
determined. The harbor deepening project at Miami Harbor in 2005 to 
2006 estimated between 200 to 250 days of blasting with one shot per 
day (a blast day) to pre-treat the rock associated with that project; 
however, the contractor completed the project in 38 days with 40 
blasts. The upcoming expansion at Miami Harbor scheduled to begin in 
summer/fall of 2012 currently estimates a maximum of 600 blast days for 
the entire project footprint. While blasting events will occur only 
during the day, other operations associated with the proposed action 
will take place 24 hours a day, typically six days a week. The 
contractor may drill the blast array at night and then blast after at 
least two hours after sunrise (1 hour, plus one hour of monitoring). 
After detonation of the first explosive array, a second array may be 
drilled and detonated before the one-hour before sunset prohibition is 
triggered. Blasting activities normally will not take place on Sundays 
due to local ordinances.
    At this time, the ACOE has not selected a contractor and thus, does 
not have a contractor-developed blasting plan from the contractor 
specifically identifying the number of holes that will be drilled, the 
amount of explosives that will be used for each hole, the number of 
blasts per day (usually no more than two per a day) or the number of 
days the construction is anticipated to take to complete. The ACOE is 
required to have

[[Page 71519]]

all authorizations and permits completed (including the possession of 
an IHA) prior to the request for proposal and advertising the contract, 
per the Competition in Contracting Act, and the Federal Acquisition 
Regulations. While the ACOE does not have contract bids at this time, 
it is possible to make reasonable estimates of the bounds based on 
previous similar projects that have been conducted by the ACOE here and 
at other locations. NMFS concurs with the use of the worse case 
scenarios in order to estimate blasting activities and associated 
potential impacts.
    Blast holes are small in diameter and only 5 to 10 ft (1.5 to 3.1 
m) deep, drilling activities take place for a short time duration, with 
no more than three holes being drilled at the same time (based on the 
current drill-rigs available in the industry that range from one to 
three drills). During the 2005 blasting event, dolphins were seen near 
the drill barge during drilling events and the ACOE did not observe 
avoidance behavior. No measurements associated with noise from drilling 
small blast holes have been recorded. The ACOE does not expect 
incidental harassment from drilling operations and is not requesting 
take associated with this activity.
    Although the ACOE does not have a specific contractor-provided 
blasting plan, the ACOE developed plans and specifications for the 
project that direct the contractor to do certain things in certain ways 
and are basing these plans and specifications on the previous deepening 
project in Miami Harbor (construction was conducted in 2005 to 2006).
    The previous ACOE project in Miami Harbor required a maximum weight 
of explosives used in each delay of 376 pounds (lb) (170.6 kilograms 
[kg]) and the contractors blasted once or twice daily from June 25 to 
August 25, 2005, for a total of 40 individual blasts in 38 days of 
blasting. The 2005 project blasting was limited to Fisherman's Channel 
and the Dodge-Lummus Island Turning Basin (see Figure 2 of ACOE's IHA 
application, which shows the blasting footprint for the 2005 project), 
whereas the project described in the ACOE's application includes 
Fisherman's Channel, Dodge-Lummus Island Turning Basin, Fisher Island 
Turning Basin, and Inner and Outer Entrance Channel. This larger area 
will result in more blasting for this project than was completed in 
2005, as it includes areas not previously blasted in 2005.
    A copy of the Federal Register notice of issuance for the IHA from 
2003 (68 FR 32016, May 29, 2003), the IHA renewal from 2005 (70 FR 
21174, April 25, 2005), and the final biological monitoring report from 
the ACOE's Miami Harbor Phase II project (completed in 2006) is 
attached to the ACOE's application and available on NMFS's Web site at: 
https://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha. For the new 
construction at Miami Harbor, the ACOE expects the proposed project may 
take multiple years, and the ACOE will seek subsequent renewals of this 
IHA after issuance, with sufficient time to prevent any delay to the 
project.
    For the proposed deepening at Miami Harbor, the ACOE has consulted 
with blasting industry experts and believe, that based on the rock 
hardness and composition at Miami Harbor, a maximum charge weight per 
delay of 450 lbs (204.1 kg) should be expected. The minimum charge 
weight will be 10 lbs (4.5 kg).
    The focus of the proposed blasting work at the Miami Harbor is to 
pre-treat the massive limestone formation that makes up the base of 
Miami Harbor prior to removal by a dredge utilizing confined blasting, 
meaning the explosive shots would be ``confined'' in the rock. 
Typically, each blast array is set up in a square or rectangle area 
divided into rows and columns (see Figures 3, 4, and 5 in the ACOE's 
IHA application). An average blast array is 10 holes long by 4 holes 
wide with holes being spaced 40 ft (12.2 m) apart covering an area of 
4,000 ft\2\ (371.6 m\2\). Blast arrays near bulkheads can be long-
linear feature of one-hole wide by 8 or 10 holes long (see Figure 4 of 
the IHA application).
    In confined blasting, each charge is placed in a hole drilled in 
the rock approximately 5 to 10 ft (1.5 to 3.0 m) deep; depending on how 
much rock/concrete needs to be broken and the intended project depth. 
The hole is then capped with an inert material, such as crushed rock. 
This process is referred to as ``stemming the hole'' (see Figure 6 and 
7 of ACOE's IHA application; each bag as shown contains approximate 
volume of material used per discharge). The ACOE used this technique 
previously at the Miami Harbor Phase II project in 2005. NMFS issued an 
IHA for that operation on May 22, 2003 (68 FR 32016, May 29, 2003) and 
renewed the IHA on April 19, 2005 (70 FR 21174, April 25, 2005).
    For the Port of Miami expansion project (Miami Harbor Phase II) 
that used blasting as a pre-treatment technique, the stemming material 
was angular crushed rock. (Stemming is the process of filling each 
borehole with crushed rock after the explosive charge has been placed. 
After the blasting charge has been set, then the chain of explosives 
within the rock is detonated. Stemming reduces the strength of the 
outward pressure wave produced by blasts.) The optimum size of stemming 
material is material that has an average diameter of approximately 0.05 
times the diameter of the blast-hole. The selected material must be 
angular to perform properly (Konya, 2003). For the ACOE's proposed 
project, specifications will be prepared by the geotechnical branch of 
the Jacksonville District.
    In the Miami Harbor Phase II project, the following requirements 
were in the specifications regarding stemming material:

1.22.9.20 Stemming

    All blast holes shall be stemmed. The Blaster or Blasting 
Specialist shall determine the thickness of stemming using blasting 
industry conventional stemming calculations. The minimum stemming 
shall be 2 ft (0.6 m) thick. Stemming shall be placed in the blast 
hole in a zone encompassed by competent rock. Measures shall be 
taken to prevent bridging of explosive materials and stemming within 
the hole. Stemming shall be clean, angular to sub-angular, hard 
stone chips without fines having an approximate diameter of \1/2\ 
inch (in; 1.3 centimeters [cm]) to \3/8\ in (1 cm). A barrier shall 
be placed between the stemming and explosive product, if necessary, 
to prevent the stemming from setting into the explosive product. 
Anything contradicting the effectiveness of stemming shall not 
extend through the stemming (see Figure 6 of ACOE's IHA application 
for a typical drill hole configuration with stemming).

    The specifications for any construction utilizing the blasting for 
the deepening of Miami Harbor would have similar stemming requirements 
as those that were used for the Miami Harbor Phase II project in 2005 
to 2006. The length of stemming material would vary based on the length 
of the hole drilled, however minimum lengths would be included in the 
project specific specifications. Studies have shown that stemmed blasts 
have up to a 60 to 90 percent decrease in the strength of the pressure 
wave 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 (unconfined) blasts (see Figure 8 of 
ACOE's IHA application), very little peer-reviewed research exists on 
the effects that confined blasting can have on marine animals near the 
blast (Keevin et al., 1999). The visual evidence from a typical 
confined blast is shown in Figure 9 of ACOE's IHA application.
    In confined blasting, the detonation is conveyed from the drill 
barge to the

[[Page 71520]]

primer and the charge itself by Primacord and Detaline. These are used 
to safety fire the blast from a distance to ensure human safety from 
the blast. The Primacord and Detaline used on this project have a 
specific grain weight, and they burn like a fuse. They are not 
electronic. The time delay from activation to detonation of the charge 
is less than one second.
    As part of the development of the protected species monitoring and 
mitigation protocols, which will be incorporated into the plans and 
specification for the proposed project, ACOE will continue to 
coordinate with the resource agencies and non-governmental 
organizations (NGOs) to address concerns and potential impacts 
associated with the use of blasting as a construction technique.
    To estimate the maximum poundage of explosives that may be utilized 
for this proposed project, the ACOE has reviewed two previous blasting 
projects, one at San Juan Harbor, Puerto Rico in 2000, and one at Miami 
Harbor, Florida in 2005. The San Juan Harbor project's heaviest blast 
event using explosives was 375 lbs (170.1 kg) per delay and in Miami it 
was 376 lbs (170.6 kg) per delay. Based on discussion with the ACOE's 
geotechnical engineers, it is expected that the maximum weight of 
delays for Miami Harbor will be larger since the rock is much harder 
than what is seen at the Port of Miami.
    Based upon industry standards and ACOE Safety & Health Regulations, 
the blasting program may consist of the following:
     The weight of explosives to be used in each blast will be 
limited to the lowest poundage of explosives that can adequately break 
the rock.
     Drill patterns are restricted to a minimum of 8 ft (2.4 m) 
separation from a loaded hole.
     Hours of blasting are restricted from two hours after 
sunrise to one hour before sunset to allow for adequate observation of 
the proposed project area for marine mammals.
     Selection of explosive products and their practical 
application method must address vibration and air blast (overpressure) 
control for protection of existing structures and marine wildlife.
     Loaded blast holes will be individually delayed to reduce 
the maximum lbs per delay at point detonation, which in turn will 
reduce the mortality radius.
     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 with a minimum of 8 milliseconds 
(ms) between delay detonations to stagger the blast pressures and 
prevent cumulative addition of pressures in the water.

Test Blast Program

    Prior to implementing a construction blasting program, a test blast 
program will be completed. The test blast program will have all the 
same protective monitoring and mitigation measures in place for 
protected species as blasting operations for construction purposes. The 
purpose of the test 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; and
     Calibration of the environment.
    The test blast program begins with a single range of individually 
delayed holes and progresses up to the maximum production blast 
intended for use. The test blast program will take place in the 
proposed project area and will count toward the pre-treatment of 
material, since the blasts of the test blast program will be cracking 
rock. Each test blast is designed to establish limits of vibration and 
air blast overpressure, with acceptable rock breakage for excavation. 
The final test 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 formatted in a 
regression analysis with other pertinent information and conclusions 
reached. This will be the basis for developing a completely engineered 
procedure for the construction blasting plan.
    During the test blast program, the following data will be used to 
develop a regression analysis:
     Distance;
     Pounds per delay;
     Peak particles velocities (Threshold Limit Value [TVL]);
     Frequencies (TVL);
     Peak vector sum; and
     Air blast, overpressure.
    Additional details regarding the proposed blasting and dredging 
project can be found in the ACOE's IHA application and EIS. The EIS can 
also be found online at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.

Description of the Proposed Dates, Duration, and Specified Geographic 
Region

    At this time the ACOE has not yet a specific date for the 
initiation of construction activities within the Port of Miami. 
However, the ACOE requests that the IHA to be issued by NMFS by 
November 30, 2011, to allow for the advertisement of the contract for 
construction in January, 2012; award the contract and provide the 
notice to proceed to the selected in May, 2012 to the selected 
contractor, resulting in construction work beginning after June, 2012. 
The proposed construction activities are expected to take up to 24 
months and at this time, it is possible that blasting could take place 
at any time during construction. The ACOE also notes that multiple IHAs 
(up to three) will be needed and requested for this project due to the 
project duration.
    The proposed blasting activities will be limited to waters 
shallower than 60 ft (18.3 m), and located entirely on the continental 
shelf and will not take place seaward of the outer reef. The specified 
geographic area of the construction will be within the boundaries of 
the Port of Miami, in Miami, Florida (see Figure 11 of the ACOE's IHA 
application). The Port of Miami is an island facility consisting of 518 
upland acres and is located in the northern portion of Biscayne Bay in 
South Florida. The City of Miami is located on the west side of the 
Biscayne Bay; the City of Miami Beach is located on an island on the 
northeast side of Biscayne Bay, opposite of Miami. Both cities are 
located in Miami-Dade County, Florida, and are connected by several 
causeways crossing the bay. The Port of Miami is the southernmost major 
port on the Atlantic Coast. The Port of Miami's landside facilities are 
located on Dodge-Lummus Island, which has a GPS location 25[deg] 
46'05'' North 80[deg] 09'40'' West. See Figure 11 of the ACOE's IHA 
application for more information on the location of the proposed 
project area in the Port of Miami.

Description of Marine Mammals in the Area of the Proposed Specified 
Activity

    Several cetacean species and a single species of sirenian are known 
to or could occur in the Miami Harbor action area and off the Southeast 
Atlantic coastline (see Table 1 below). Species listed as endangered 
under the U.S. Endangered Species Act (ESA), includes the humpback 
(Megaptera novaeangliae), sei (Balaenoptera borealis), fin 
(Balaenoptera physalus), blue (Balaenoptera musculus), North Atlantic 
right (Eubalaena glacialis), and

[[Page 71521]]

sperm (Physeter macrocephalus) whale, and West Indian (Florida) manatee 
(Trichechus manatus latirostris). The marine mammals that occur in the 
Atlantic Ocean off the U.S. southeast coast belong to three taxonomic 
groups: mysticetes (baleen whales), odontocetes (toothed whales), and 
sirenians (the manatee). The West Indian manatee in Florida and U.S. 
waters is managed under the jurisdiction of the U.S. Fish and Wildlife 
Service (USFWS) and therefore is not considered further in this 
analysis.
    Table 1 below outlines the marine mammal species and their habitat 
in the region of the proposed project area.

    Table 1--The Habitat and Conservation Status of Marine Mammals Inhabiting the Proposed Study Area in the
                                   Atlantic Ocean off the U.S. Southeast Coast
----------------------------------------------------------------------------------------------------------------
               Species                         Habitat                  ESA \1\                  MMPA \2\
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Atlantic right whale         Coastal and shelf......  EN.....................  D.
     (Eubalaena glacialis).
    Humpback whale (Megaptera          Pelagic, nearshore       EN.....................  D.
     novaeangliae).                     waters, and banks.
    Bryde's whale (Balaenoptera        Pelagic and coastal....  NL.....................  NC.
     brydei).
    Minke whale (Balaenoptera          Shelf, coastal, and      NL.....................  NC.
     acutorostrata).                    pelagic.
    Blue whale (Balaenoptera           Pelagic and coastal....  EN.....................  D.
     musculus).
    Sei whale (Balaenoptera borealis)  Primarily offshore,      EN.....................  D.
                                        pelagic.
    Fin whale (Balaenoptera physalus)  Slope, mostly pelagic..  EN.....................  D.
Odontocetes:
    Sperm whale (Physeter              Pelagic, deep seas.....  EN.....................  D.
     macrocephalus).
    Cuvier's beaked whale (Ziphius     Pelagic................  NL.....................  NC.
     cavirostris).
    Gervais' beaked whale (Mesoplodon  Pelagic................  NL.....................  NC.
     europaeus).
    True's beaked whale (Mesoplodon    Pelagic................  NL.....................  NC.
     mirus).
    Blainville's beaked whale          Pelagic................  NL.....................  NC.
     (Mesoplodon densirostris).
    Dwarf sperm whale (Kogia sima)...  Offshore, pelagic......  NL.....................  NC.
    Pygmy sperm whale (Kogia           Offshore, pelagic......  NL.....................  NC.
     breviceps).
    Killer whale (Orcinus orca)......  Widely distributed.....  NL.....................  NC.
                                                                EN (Southern Resident).  D (Southern Resident,
                                                                                          AT1 Transient).
    Short-finned pilot whale           Inshore and offshore...  NL.....................  NC.
     (Globicephala macrorhynchus).
    False killer whale (Pseudorca      Pelagic................  NL.....................  NC.
     crassidens).
    Mellon-headed whale                Pelagic................  NL.....................  NC.
     (Peponocephala electra).
    Pygmy killer whale (Feresa         Pelagic................  NL.....................  NC.
     attenuata).
    Risso's dolphin (Grampus griseus)  Pelagic, shelf.........  NL.....................  NC.
    Bottlenose dolphin (Tursiops       Offshore, Inshore,       NL.....................  NC.
     truncatus).                        coastal, and estuaries.                          S (Biscayne Bay and
                                                                                          Central Florida
                                                                                          Coastal stocks).
                                                                                         D (Western North
                                                                                          Atlantic Coastal).
    Rough-toothed dolphins (Steno      Pelagic................  NL.....................  NC.
     bredanensis).
    Fraser's dolphin (Lagenodelphis    Pelagic................  NL.....................  NC.
     hosei).
    Striped dolphin (Stenella          Pelagic................  NL.....................  NC.
     coeruleoalba).
    Pantropical spotted dolphin        Pelagic................  NL.....................  NC.
     (Stenella attenuata).                                                               D (Northeastern
                                                                                          Offshore).
    Atlantic spotted dolphin           Coastal to pelagic.....  NL.....................  NC.
     (Stenella frontalis).
    Spinner dolphin (Stenella          Mostly pelagic.........  NL.....................  NC.
     longirostris).                                                                      D (Eastern).
    Clymene dolphin (Stenella          Pelagic................  NL.....................  NC.
     clymene).
Sirenians:

[[Page 71522]]

 
    West Indian (Florida) manatee      Coastal, rivers, and     EN.....................  D.
     (Trichechus manatus latirostris).  estuaries.
----------------------------------------------------------------------------------------------------------------
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, NC = Not classified.

    The one species of marine mammal under NMFS jurisdiction known to 
commonly occur in close proximity to the proposed blasting area of the 
Port of Miami is the Atlantic bottlenose dolphin, specifically the 
stocks living near the Port of Miami within Biscayne Bay (the Biscayne 
Bay stock) or transiting the outer entrance channel (Western North 
Atlantic Central Florida Coastal stock).

Atlantic Bottlenose Dolphin

    Atlantic bottlenose dolphins are distributed worldwide in tropical 
and temperate waters, and in U.S. waters occur in multiple complex 
stocks along the U.S. Atlantic coast. The coastal morphotype of 
bottlenose dolphins is continuously distributed along the Atlantic 
coast south of Long Island, New York, to the Florida peninsula, 
including inshore waters of the bays, sounds, and estuaries. Except for 
animals residing within the Southern North Carolina and Northern North 
Carolina Estuarine Systems (e.g., Waring et al., 2009), estuarine 
dolphins along the U.S. east coast have not been previously included in 
stock assessment reports. Several lines of evidence support a 
distinction between dolphins inhabiting coastal waters near the shore 
and those present in the inshore waters of the bays, sounds, and 
estuaries. Photo-identification (photo-ID) and genetic studies support 
the existence of resident estuarine animals in several inshore areas of 
the southeastern United States (Caldwell, 2001; Gubbins, 2002; Zolman, 
2002; Mazzoil et al., 2005; Litz, 2007), and similar patterns have been 
observed in bays and estuaries along the Gulf of Mexico coast (Well et 
al., 1987; Balmer et al., 2008). Recent genetic analyses using both 
mitochondrial DNA and nuclear microsatellite markers found significant 
differentiation between animals biopsied along the coast and those 
biopsied within the estuarine systems at the same latitude (NMFS, 
unpublished data). Similar results have been found off the west coast 
of Florida (Sellas et al., 2005).

Biscayne Bay Stock

    Biscayne Bay is a shallow estuarine system located along the 
southeast coast of Florida in Miami-Dade County. The Bay is generally 
shallow (depths greater than 5 m [16.4 ft]) and includes a diverse 
range of benthic communities including seagrass beds, soft coral and 
sponge communities, and mud flats. The northern portion of Biscayne Bay 
is surrounded by the cities of Miami and Miami Beach and is therefore 
heavily influenced by industrial and municipal pollution sources. The 
water flow in this portion of Biscayne Bay is very restricted due to 
the construction of dredged islands (Bialczak et al., 2001). In 
contrast, the central and southern portions of Biscayne Bay are less 
influenced by development and are better flushed. Water exchange with 
the Atlantic Ocean occurs through a broad area of grass flats and tidal 
channels termed the Safety Valve. Biscayne Bay extends south through 
Card Sound and Barnes Sound, and connects through smaller inlets to 
Florida Bay.
    The Biscayne Bay stock of bottlenose dolphins is bounded by 
Haulover Inlet to the north and Card Sound Bridge to the south. This 
range corresponds to the extent of confirmed home ranges of bottlenose 
dolphins observed residing in Biscayne Bay by a long-term photo-ID 
study conducted by the Southeast Fisheries Science Center (Litz, 2007; 
SEFSC unpublished data). It is likely that the range of Biscayne Bay 
dolphins extends past these boundaries; however, there have been few 
surveys outside of this range. These boundaries are subject to change 
upon further study of dolphin home ranges within the Biscayne Bay 
estuarine system and comparison to an extant photo-ID catalog from 
Florida Bay to the south.
    Dolphins residing within estuaries north of this stock along the 
southeastern coast of Florida are currently not included in a stock 
assessment report. There are insufficient data to determine whether 
animals in this region exhibit affiliation to the Biscayne Bay stock, 
the estuarine stock further to the north in the Indian River Lagoon 
Estuarine System (IRLES), or are simply transient animals associated 
with coastal stocks. There is relatively limited estuarine habitat 
along this coastline; however, the Intracoastal Waterway extends north 
along the coast to the IRLES. It should be noted that during 2003 to 
2007, there were three stranded bottlenose dolphins in this region in 
enclosed waters. One of these had signs of human interaction from a 
boat strike and another was identified as an offshore morphotype of 
bottlenose dolphin.
    Bottlenose dolphins have been documented in Biscayne Bay since the 
1950's (Moore, 1953). Live capture fisheries for bottlenose dolphins 
are known to have occurred throughout the southeastern U.S. and within 
Biscayne Bay during the 1950's and 1960's; however, it is unknown how 
many individuals may have been removed from the population during this 
period (Odell, 1979; Wells and Scott, 1999).
    The Biscayne Bay bottlenose dolphin stock has been the subject of 
an ongoing photo-ID study conducted by the NMFS SEFSC since 1990. From 
1990 to 1991, preliminary information was collected focusing on the 
central portion of Biscayne Bay. The survey was re-initiated in 1994, 
and it was expanded to include the northern portion of Biscayne Bay and 
south to the Card Sound Bridge in 1995 (SEFSC unpublished data; Litz, 
2007). Through 2007, the photo-ID catalog included 229 unique 
individuals. Approximately 80% of these individuals may be long-term 
residents with multiple sightings over the 17 years of the study 
(SEFSC, unpublished data). Analyses of the sighting histories and 
associations of individuals from the Biscayne Bay segregated along a 
north/south gradient (Litz, 2007).
    Remote biopsy samples of Biscayne Bay animals were collected 
between 2002 and 2004 for analyses of population genetic structure and 
persistent organic pollutant concentrations in blubber. Genetic 
structure was investigated using both mitochondrial DNA and nuclear 
(microsatellite) markers, and the data from Biscayne Bay were compared 
to data from Florida Bay dolphins to the south (Litz, 2007). Within 
Biscayne Bay, dolphins sighted primarily in the northern half of 
Biscayne Bay were significantly differentiated from those sighted 
primarily in the southern half at the microsatellite loci but not at 
the

[[Page 71523]]

mitochondrial locus. There was not sufficient genetic information 
between these groups to indicate true population subdivision (Litz, 
2007). However, genetic differentiation was found between the Biscayne 
Bay and Florida Bay dolphins in both markers (Litz, 2007). The observed 
genetic differences between resident animals in Biscayne Bay and those 
in an adjacent estuary combined with the high levels of sight fidelity 
observed, demonstrate that the resident Biscayne Bay bottlenose 
dolphins are a demographically distinct population stock.
    The total number of bottlenose dolphins in the Biscayne Bay stock 
is unknown. During small boat surveys between 2003 and 2007, 157 unique 
individuals were identified using standard methods, however, this 
catalog size does not represent a valid estimate of population size 
because the residency patterns of dolphins in Biscayne Bay is not fully 
understood. Litz (2007) determined that 69 animals in Biscayne Bay have 
a northern home range. Based on Waring et al. (2010), the maximum 
population of animals that may be in the proposed project area is equal 
to the total number of uniquely identified animals for the entire 
photo-ID study of Biscayne Bay--229 individuals. Present data are 
insufficient to calculate a minimum population estimate, and to 
determine the population trends, for the Biscayne Bay stock of 
bottlenose dolphins. The total human-caused mortality and serious 
injury for this stock is unknown and there is insufficient information 
available to determine whether the total fishery-related mortality and 
serious injury for this stock is insignificant and approaching zero 
mortality and serious injury rate. Documented human-caused mortalities 
in recreational fishing gear entanglement and ingestion of gear 
reinforce concern for this stock. Because the stock size is currently 
unknown, but likely small and relatively few mortalities and serious 
injuries would exceed potential biological removal, NMFS considers this 
stock to be a strategic stock.

Western North Atlantic Central Florida Coastal Stock

    On the Atlantic coast, Scott et al. (1988) hypothesized a single 
coastal migratory stock ranging seasonally from as far north as Long 
Island, to as far south as central Florida, citing stranding patterns 
during a high mortality event in 1987 to 1988 and observed density 
patterns. More recent studies demonstrate that the single coastal 
migratory stock hypothesis is incorrect, and there is instead a complex 
mosaic of stocks (McLellan et al., 2003; Rosel et al., 2009).
    The coastal morphotype is morphologically and genetically distinct 
from the larger, more robust morphotype primarily occupying habitats 
further offshore (Hoelzel et al., 1998; Mead and Potter, 1995; Rosel et 
al., 2009). Aerial surveys conducted between 1978 and 1982 (CETAP, 
1982) north of Cape Hatteras, North Carolina, identified two 
concentrations of bottlenose dolphins, one inshore of the 82 ft (25 m) 
isobath and the other offshore of the 164 ft (50 m) isobath. The lowest 
density of bottlenose dolphins was observed over the continental shelf, 
with higher densities along the coast and near the continental shelf 
edge. It was suggested, therefore, that north of Cape Hatteras, North 
Carolina, the coastal morphotype is restricted to waters less than 82 
ft deep (Kenney, 1990). Similar patterns were observed during summer 
months in more recent aerial surveys (Garrison and Yeung, 2001; 
Garrison et al., 2003). However, south of Cape Hatteras during both 
winter and summer months, there was no clear longitudinal discontinuity 
in bottlenose dolphin sightings (Garrison and Yeung 2001; Garrison et 
al., 2003). To address the question of distribution of coastal and 
offshore morphotypes in waters south of Cape Hatteras, tissue samples 
were collected from large vessel surveys during the summers of 1998 and 
1999, from systematic biopsy sampling efforts in nearshore waters from 
New Jersey to central Florida conducted in the summers of 2001 and 
2002, and from winter biopsy collection effort in 2002 and 2003 in 
nearshore continental shelf waters of North Carolina and Georgia. 
Additional biopsy samples were collected in deeper continental shelf 
waters south of Cape Hatteras during the winter of 2002. Genetic 
analyses using mitochondrial DNA sequences of these biopsies identified 
individual animals to the coastal or offshore morphotype. Using the 
genetic results from all surveys combined, a logistic regression was 
used to model the probability that a particular bottlenose dolphin 
group was of the coastal morphotype as a function of environmental 
variables including depth, sea surface temperature, and distance from 
shore. These models were used to partition the bottlenose dolphin 
groups observed during aerial surveys between the two morphotypes 
(Garrison et al., 2003).
    The genetic results and spatial patterns observed in aerial surveys 
indicate both regional and seasonal differences in the longitudinal 
distribution of the two morphotypes in coastal Atlantic waters. 
Generally, from biopsy samples collected, the coastal morphotype is 
found in nearshore waters, the offshore morphotype in deeper waters and 
a spatial overlap between the two morphotypes in intermediate waters. 
More information on the seasonal differences and genetic studies off of 
the Carolina's, Georgia, and Florida, differentiating morphotypes of 
bottlenose dolphins can be found online in the NMFS stock assessment 
reports.
    In summary, the primary habitat of the coastal morphotype of 
bottlenose dolphin extends from Florida to New Jersey during summer 
months and in waters less than 65.6 ft (20 m) deep, including estuarine 
and inshore waters.
    In addition to inhabiting coastal nearshore waters, the coastal 
morphotype of bottlenose dolphin also inhabits inshore estuarine waters 
along the U.S. east coast and Gulf of Mexico (Wells et al., 1987; Wells 
et al., 1996; Scott et al., 1990; Weller, 1998; Zolman, 2002; Speakman 
et al., 2006; Stolen et al., 2007; Balmer et al., 2008; Mazzoil et al., 
2008). There are multiple lines of evidence supporting demographic 
separation between bottlenose dolphins residing within estuaries along 
the Atlantic coast. In Biscayne Bay, Florida, there is a similar 
community of bottlenose dolphins with evidence of year-round residents 
that are genetically distinct from animals residing in a nearby estuary 
in Florida Bay (Litz, 2007). A few published studies demonstrate that 
there are significant genetic distinctions and differences between 
animals in nearshore coastal waters and estuarine waters (Caldwell, 
2001; Rosel et al., 2009). Despite evidence for genetic differentiation 
between estuarine and nearshore populations, the degree of spatial 
overlap between these populations remains unclear. Photo-ID studies 
within estuaries demonstrate seasonal immigration and emigration and 
the presence of transient animals (e.g., Speakman et al., 2006). In 
addition, the degree of movement of resident estuarine animals into 
coastal waters on seasonal or shorter time scales is poorly understood. 
However, for the purposes of this analysis, bottlenose dolphins 
inhabiting primarily estuarine habitats are considered distinct from 
those inhabiting coastal habitats. Initially, a single stock of coastal 
morphotype bottlenose dolphins was thought to migrate seasonally 
between New Jersey (summer months) and central Florida based on 
seasonal patterns in strandings during a large scale mortality event 
occurring during 1987 to 1988 (Scott et al., 1988). However, re-
analysis of

[[Page 71524]]

stranding data (McLellan et al., 2003) and extensive analysis of 
genetic (Rosel et al., 2009), photo-ID (Zolman, 2002) and satellite 
telemetry (NMFS, unpublished data) data demonstrate a complex mosaic of 
coastal bottlenose dolphin stocks. Integrated analysis of these 
multiple lines of evidence suggests that there are five coastal stocks 
of bottlenose dolphins: The Northern Migratory and Southern Migratory 
stocks, a South Carolina/Georgia Coastal stock, a Northern Florida 
Coastal stock, and a Central Florida Coastal stock.
    The spatial extent of these stocks, their potential seasonal 
movements, and their relationships with estuarine stocks are poorly 
understood. More information on the migratory movements and genetic 
analyses of bottlenose dolphins can be found online in the NMFS stock 
assessment reports.
    The NMFS stock assessment report addresses the Central Florida 
Coastal stock, which is present in coastal Atlantic waters from 
29.4[deg] North south to the western end of Vaca Key (approximately 
24.69[deg] North to 81.11[deg] West) where the stock boundary for the 
Florida Keys stock begins (see Figure 1 of the NMFS Stock Assessment 
Report). There has been little study of bottlenose dolphin stock 
structure in coastal waters of southern Florida; therefore the southern 
boundary of the Central Florida stock is uncertain. There is no obvious 
boundary defining the offshore extent of this stock. The combined 
genetic and logistic regression analysis (Garrison et al., 2003) 
indicated that in waters less than 32.8 ft (10 m) depth, 70% of the 
bottlenose dolphins were of the coastal morphotype. Between 32.8 ft and 
65.6 ft depth, the percentage of animals of the coastal morphotype 
dropped precipitously, and at depths greater than 131.2 ft (40 m) 
nearly all (greater than 90%) animals were of the offshore morphotype. 
These spatial patterns may not apply in the Central Florida Coastal 
stock, as there is a significant change in the bathymetric slope and a 
close approach of the Gulf Stream to the shoreline south of Cape 
Canaveral.
    Aerial surveys to estimate the abundance of coastal bottlenose 
dolphins in the Atlantic were conducted during winter (January to 
February) and summer (July to August) of 2002. Abundance estimates for 
bottlenose dolphins in each stock were calculated using line-transect 
methods and distance analysis (Buckland et al., 2001). More information 
on the survey tracklines, design, effort, animals sighted, and methods 
for calculating estimated abundance can be found online in the NMFS 
stock assessment reports.
    The estimated best and minimum population for the Central Florida 
Coastal Stock is 6,318 and 5,094 animals, respectively. There are 
insufficient data to determine the population trends for this stock. 
From 1995 to 2001, NMFS recognized only a single migratory stock of 
coastal bottlenose dolphins in the western North Atlantic, and the 
entire stock was listed as depleted. This stock structure was revised 
in 2002 to recognize both multiple stocks and seasonal management units 
and again in 2008 and 2010 to recognize resident estuarine stocks and 
migratory and resident coastal stocks. The total U.S. fishery-related 
mortality and serious injury for the Central Florida Coastal stock 
likely is less than 10% of the calculated PBR, and thus can be 
considered to be insignificant and approaching zero mortality and 
serious injury rate. However, there are commercial fisheries 
overlapping with this stock that have no observer coverage. This stock 
retains the depleted designation as a result of its origins from the 
originally delineated depleted coastal migratory stock. The species is 
not listed as threatened or endangered under the ESA, but this is a 
strategic stock due to the depleted listing under the MMPA.
    Further information on the biology and local distribution of these 
species and others in the region can be found in ACOE's IHA 
application, which is available upon request (see ADDRESSES), and the 
NMFS Marine Mammal Stock Assessment Reports, which are available online 
at: https://www.nmfs.noaa.gov/pr/species/.

Potential Effects on Marine Mammals

    In general, potential impacts to marine mammals from explosive 
detonations could include mortality, serious injury, as well as Level A 
harassment (injury) and Level B harassment. In the absence of 
monitoring and mitigation, marine mammals may 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. Effects 
are likely to be most severe in near surface waters where the reflected 
shock wave creates a region of negative pressure called ``cavitation.''
    A second potential possible cause of mortality 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.
    NMFS's criteria for determining non-lethal injury (Level A 
harassment) from explosives are the peak pressure that will result in: 
(1) The onset of slight lung hemorrhage, or (2) a 50 percent 
probability level for a rupture of the tympanic membrane (TM). These 
are injuries from which animals would be expected to recover on their 
own.
    NMFS has established dual criteria for what constitutes Level B 
harassment: (1) An energy based temporary threshold shift (TTS) 
received sound levels 182 dB re 1 [mu]Pa\2\-s cumulative energy flux in 
any \1/3\ octave band above 100 Hz for odontocetes (derived from 
experiments with bottlenose dolphins (Ridgway et al., 1997; Schlundt et 
al., 2000); and (2) 12 psi peak pressure cited by Ketten (1995) as 
associated with a safe outer limit for minimal, recoverable auditory 
trauma (i.e., TTS). The Level B harassment zone, therefore, is the 
distance from the mortality, serious injury, injury (Level A 
harassment) zone to the radius where neither of these criterion is 
exceeded.

[[Page 71525]]



     Table 2--NMFS's Threshold Criteria and Metrics Utilized for Impact Analyses From the Use of Explosives
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
            Mortality                       Level A Harassment            Level B Harassment  Level B Harassment
                                            (Non-lethal injury)             (Non-injurious;     (Non-injurious
                                                                                TTS and         behavioral, Sub-
                                                                               associated             TTS)
                                                                               behavioral
                                                                            disruption [dual
                                                                               criteria])
----------------------------------------------------------------------------------------------------------------
31 psi-msec (onset of severe      205 dB re 1         13 psi-msec         182 dB re 1         177 dB re 1
 lung injury [mass of dolphin      [mu]Pa\2\[middot]   positive pressure   [mu]Pa\2\[middot]   [mu]Pa\2\[middot]
 calf]).                           s EFD (50 percent   (onset of slight    s EFD*; 23 psi      s EFD* (for
                                   of animals would    lung injury).       peak pressure (<    multiple
                                   experience TM                           2,000 lb) 12 psi    detonations only)
                                   rupture).                               peak pressure (<=
                                                                           2,000 lb).
----------------------------------------------------------------------------------------------------------------
* Note: In greatest \1/3\-octave band above 10 Hz or 100 Hz.

    The primary potential impact to the Atlantic bottlenose dolphins 
occurring in the Port of Miami action area from the proposed 
detonations is Level B harassment incidental to noise generated by 
explosives. In the absence of any monitoring or mitigation measures, 
there is a very small chance that a marine mammal could be injured, 
seriously injured, or killed when exposed to the energy generated from 
an explosive force on the sea floor. However, the ACOE and NMFS 
believes that the proposed monitoring and mitigation measures will 
preclude this possibility in the case of this particular proposed 
activity.
    Non-lethal injurious impacts (Level A harassment) are defined in 
this proposed IHA as TM rupture and the onset of slight lung injury. 
The threshold for Level A harassment corresponds to a 50 percent rate 
of TM rupture, which can be stated in terms of an energy flux density 
(EFD) value of 205 dB re 1 [mu]Pa\2\s. TM rupture is well-correlated 
with permanent hearing impairment (Ketten, 1998) indicates a 30 percent 
incidence of permanent threshold shift (PTS) at the same threshold. The 
farthest distance from the source at which an animal is exposed to the 
EFD level for the Level A harassment threshold is unknown at this time.
    Level B (non-injurious) harassment includes temporary (auditory) 
threshold shift (TTS), a slight, recoverable loss of hearing 
sensitivity. One criterion used for TTS is 182 dB re 1 [mu]Pa[sup2] s 
maximum EFD level in any \1/3\-octave band above 100 Hz for toothed 
whales (e.g., dolphins). A second criterion, 23 psi, has been 
established by NMFS to provide a more conservative range of TTS when 
the explosive or animals approaches the sea surface, in which case 
explosive energy is reduced, but the peak pressure is not. For the 
proposed project in Miami Harbor, the distance from the blast array at 
which the 23 psi threshold could be met for various charge detonation 
weights can be, and has been calculated.
    Level B harassment may also include behavioral modifications 
resulting from repeated noise exposures (below TTS) to the same animals 
(usually resident) over a relatively short period of times. Threshold 
criteria for this particular type of harassment are currently still 
being considered. One recommendation is a level of 6 dB below TTS (see 
69 FR 21816, April 22, 2004), which would be 177 dB re 1 [mu]Pa\2\s. 
The Level B harassment (behavioral) threshold criteria would not apply 
to the ACOE's proposed activity because there will only two blasting 
events a day, and the multiple (staggered) detonations are within a few 
microseconds of each other and do not last more than a few seconds in 
total duration per a blasting event.
    For an open-water, unconfined blast, the pressure edge of the 
danger zone is expected to be 23 psi. For a fully confined blast, the 
pressure at the edge of the danger zone is expected to be 6 psi. 
Utilizing the pressure data collected the Miami Harbor Phase II project 
in 2005, for a maximum charge weight of 450 lbs in a fully confined 
blast, the pressure is expected to be 22 psi approximately 700 ft 
(213.4 m) from the blast, which is below the threshold for Level B 
harassment (i.e., 23 psi criteria for explosives less than 2,000 lb). 
However to ensure the protection of marine mammals, and in case of an 
incident where a detonation is not fully confined, the ACOE assumes 
that any animal within the boundaries of a designated ``danger zone'' 
would be taken by Level B harassment.
    The ACOE is planning to implement a series of monitoring and 
mitigation measures to protect marine mammals from the potential 
impacts of the proposed blasting activities. The ACOE has designated a 
``danger zone'' as the area within which the potential for Level B 
harassment occurs, and the ``exclusion zone'' as the area within which 
if an animal crosses and enters that zone then the blast will be 
delayed until the animal leaves the zone of its own volition. The 
exclusion zone is larger than the area where the ACOE has determined 
that Level B harassment will occur, so if the monitoring and mitigation 
measures implemented are successful as expected, and no detonation 
occurs when an animals is inside of the exclusion zone, no take by 
Level B harassment is likely to occur. However, to be conservative, the 
ACOE has calculated the potential exists for Level B harassment and is 
pursuing an IHA from NMFS. More information on how the danger and 
exclusion zones are determined is included in the ``Proposed 
Mitigation'' section of this document (see below).
    It has been noted on one previous occasion at the ACOE's Miami 
Harbor Phase II project in 2005 that a bottlenose dolphin outside the 
exclusion zone, in the deeper water channel, exhibited a startle 
response immediately following a blast. Details of that event from the 
monitoring report are included below:

    Any animals near the exclusion zone were watched carefully 
during the blast for any changes in behavior or noticeable reaction 
to the blast. The only observation that showed signs of a possible 
reaction to the blast was on July 27, when two dolphins were in the 
channel west of the blast. The dolphins were stationary at 
approximately 2,400 ft (731.5 m) from the blast array, feeding and 
generally cavorting. Due to the proximity of the dolphins, the drill 
barge was contacted prior to the blast to confirm that the exclusion 
zone calculation was 1,600 ft (487.7 m) for the lower weight of 
explosives used that day. The topography of the bottom in that area 
is very shallow (approximately 3.3 ft [1 m]) to the south, then an 
exceptionally steep drop off into the channel at 40 plus ft ending 
at the bulkhead wall to the north. Westward, the channel continues 
and has a more gradual upward slope. At the time of the blast, one 
of the dolphins was at the surface in the shallows, while the other 
dolphin was underwater within the channel. The dolphin that was 
underwater showed a strong reaction to the blast. The animal jumped 
fully out of the water in a `breaching' fashion; behavior that had 
not been exhibited prior to the blast. The animal was observed 
jumping out of the water immediately before the observers heard the 
blast suggesting that the animal reacted to the blast and not some 
other stimulus. It is probable that, because this animal was located 
in the channel, the sound and pressure of the blast traveled either 
farther or was more focused through

[[Page 71526]]

the channeling and the reflection from the bulkhead, thus causing 
the animal to react even though it was well outside the safety 
radius. These two dolphins were tracked for the entire 30 min post 
blast period and no obvious signs of distress or behavior changes 
were observed. Other animals observed near the safety radius during 
the blast were all to the south of the blasting array, well up on 
the seagrass beds or in the pipe channel that runs through the 
seagrass beds. None of these animals showed any reaction to the 
blast.

    Individual dolphins from other stocks and within the Biscayne Bay 
and Western North Atlantic Central Florida Coastal stocks potentially 
move both inshore and offshore of Biscayne Bay due to the openness of 
this bay system and closeness of the outer continental shelf. These 
movements are not fully understood and the possibility exists that 
these other stocks may be affected in the same manner as the Biscayne 
Bay and Western North Atlantic Central Florida Coastal stocks.
    Based on the data from the Miami Harbor project in 2005 and the 
implementation of the proposed monitoring and mitigation measures, the 
ACOE and NMFS expects limited potential effects of the proposed 
construction and blasting activities on marine mammals in the Port of 
Miami action area.

Potential Effects on Marine Mammal Habitat

    The ACOE and NMFS are unable to determine if resident bottlenose 
dolphins in the proposed action area utilize the inner and outer 
channels, walls, and substrate of the Port of Miami as habitat for 
feeding, resting, mating, or other biologically significant functions. 
The bottom of the channel has been previously blasted, and the rock and 
sand dredged. The walls of the channels are composed of vertical rock. 
The ACOE acknowledges that while the port may not be suitable foraging 
habitat for bottlenose dolphins in Biscayne Bay, it is likely that 
dolphins may use the area to traverse to and from North Biscayne Bay or 
offshore via the main channel (i.e., Government Cut).
    The ACOE and NMFS are unable to determine how the temporary 
modification of the action area by the proposed construction and 
blasting activities will potentially impact the two stocks of 
bottlenose dolphins expected to be present in the Port of Miami. If 
animals are using the Port of Miami to travel from south to north 
Biscayne Bay or vice-versa and/or exiting the bay via the main shipping 
channel, the proposed construction and blasting activities may delay or 
detour their movements.
    Blasting within the boundaries of the