Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the Explosive Removal of Offshore Structures in the Gulf of Mexico, 49568-49576 [05-16843]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 70, Number 163 (Wednesday, August 24, 2005)]
[Notices]
[Pages 49568-49576]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-16843]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 030905A]


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to the Explosive Removal of Offshore Structures in the Gulf 
of Mexico

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of receipt of application for an incidental take 
authorization; request for comments and information.

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SUMMARY: NMFS has received a request from the Minerals Management 
Service (MMS), for authorization to harass small numbers of marine 
mammals incidental to explosive severance activities at offshore oil 
and gas structures in the Gulf of Mexico (GOM) outer continental shelf 
(OCS). As a result of this request, NMFS is considering whether to 
promulgate rulemaking, that if implemented, would govern the incidental 
taking of marine mammals under individual Letters of Authorization 
(LOAs) issued to participants in this industry to take marine mammals 
by Level A and Level B harassment. In order to promulgate regulations 
and issue LOAs thereunder, NMFS must determine that these takings will 
have a negligible impact on the affected species and stocks of marine 
mammals. NMFS invites comment on MMS' application, and suggestions on 
the content of the regulations.

DATES: Comments and information must be received no later than 
September 23, 2005.

ADDRESSES: Comments on the application should be addressed to Steve 
Leathery, Chief, Permits, Conservation and Education Division, Office 
of Protected Resources, National Marine Fisheries Service, 1315 East-
West Highway, Silver Spring, MD 20910-3225, or by telephoning the 
contact listed here. The mailbox address for providing email comments 
is PR1.030905A@noaa.gov. Comments sent via e-mail, including all 
attachments, must not exceed a 10-megabyte file size. A copy of the 
application containing a list of the references used in this document 
may be obtained by writing to this address or by telephoning the 
contact listed here and is also available at: https://www.nmfs.noaa.gov/
prot_res/PR2/Small_Take/smalltake_info.htm#applications.
    A copy of MMS' Programmatic Environmental Assessment (PEA) is 
available on-line at:https://www.gomr.mms.gov/homepg/regulate/environ/
nepa/2005-013.pdf

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, NMFS, 301-
713-2055, ext 128.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and 101(a)(5)(D) of the Marine Mammal 
Protection Act (16 U.S.C. 1361 et seq.)(MMPA) direct the Secretary of 
Commerce (Secretary) 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 
regulations are issued.
    An authorization may 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, and if the permissible methods of taking 
and requirements pertaining to the monitoring and reporting of such 
takings are set forth. NMFS has defined ``negligible impact'' in 50 CFR 
216.103 as ''...an impact resulting from the specified activity that 
cannot be reasonably expected to, and is not reasonably likely to, 
adversely affect the species or stock through effects on annual rates 
of recruitment or survival.'' Except for certain categories of 
activities not pertinent here, the MMPA defines ``harassment'' as: any 
act of pursuit, torment, or annoyance which
    (i) has the potential to injure a marine mammal or marine mammal 
stock in the wild [Level A harassment]; or (ii) has the potential to 
disturb a marine mammal or marine mammal stock in the wild by 
causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment].

Summary of Request

    On February 28, 2005, NMFS received an application from MMS (MMS, 
2005a) requesting, on behalf of the offshore oil and gas industry, 
authorization under section 101(a)(5)(A) of the Marine Mammal 
Protection Act (MMPA) to harass marine mammals incidental to explosive 
severance activities at offshore oil and gas structures in the GOM OCS.

Description of the Activity

    During exploration, development, and production operations for 
mineral extraction in the GOM OCS, the seafloor around activity areas 
becomes the repository of temporary and permanent equipment and 
structures. In compliance with OCS Lands Act (OCSLA) regulations and 
MMS guidelines, operators are required to remove or ``decommission'' 
seafloor obstructions from their leases within one year of lease 
termination or after a structure has been deemed obsolete or unusable. 
To accomplish these removals, a host of activities is required to (1) 
mobilize necessary equipment and service vessels, (2) prepare the 
decommissioning targets (e.g., piles, jackets, conductors, bracings, 
wells, pipelines, etc.), (3) sever the target from the seabed and/or 
sever it into manageable components, (4) salvage the severed 
portion(s), and (5) conduct final site-clearance verification work.
    There are two primary methodologies used in the GOM for cutting 
decommissioning targets; nonexplosive and explosive severance. 
Nonexplosive methods include abrasive cutters (sand and abrasive-water 
jets), mechanical cutters (e.g., carbide or rotary), diamond wire 
cutting devices, and cutting facilitated by commercial divers using 
arc/gas torches. Though relatively time-consuming and potentially 
harmful to human health and safety (primarily for diver severances), 
nonexplosive-severance activities have little or no impact on the 
marine environment and would not result in an incidental take of marine 
mammals (MMS, 2005b-Programmatic Environmental Assessment (PEA)). A 
description of non-explosive severing tools and methods can be found in 
MMS' application and the PEA (section 1.4.7.1)(see ADDRESSES).
    Explosive-severance activities use specialized charges to achieve 
target severance. Severance charges can be deployed on multiple targets 
and detonated nearly-simultaneously (i.e., staggered at an interval of 
900 msec) effecting rapid severances. Coupled with safe-handling 
practices, the

[[Page 49569]]

reduced ``exposure time'' and omission of diver cutting also makes 
explosive severance safer for offshore workers. However, since the 
underwater detonation of cutting charges generates damaging pressure 
waves and acoustic energy, explosive-severance activities have the 
potential to result in an incidental take of nearby marine mammals. For 
this reason, MMS has requested an incidental take authorization 
governing explosive-severance activities that could be conducted under 
OCSLA structure decommissionings. Decommissioning operations conducted 
under OCSLA authority can occur on any day of a given year. Operators 
often schedule most of their decommissionings from June to December 
(approximately 80 percent) to take advantage of the often calm seas and 
good weather and the time period when structure installations tend to 
decrease since both commissioning and decommissioning operations 
compete for the same management groups, equipment, vessels, and labor 
force (TSB and CES, LSU, 2004).
    Depending upon the target, a complete decommissioning operation may 
span several days or weeks; however, the explosive-severance activity 
or ``detonation event'' for most removal targets (even those with 
multiple severances) last for only several seconds because of charge 
staggering. For complex targets or in instances where the initial 
explosive-severance attempts are unsuccessful, more than one detonation 
event may be necessary per decommissioning operation. Even though hours 
or days may pass to allow for necessary mitigation measures and 
redeployment of new charges, each detonation event would similarly last 
only for a few seconds.
    During the past 10 years (1994-2003), there has been an average of 
156 platform decommissionings per year, with over 60 percent involving 
explosive-severance activities (see Table 4 in MMS (2005a)). In 
addition to historical activity averages, many of the older, nominally-
producing structures in the mature GOM oil fields are nearing 
decommissioning age; this will result in an increase in removal 
operations in future years. Despite advancements in nonexplosive-
severance methods and the additional requisite marine protected species 
mitigations, MMS expects explosive-severance activities to continue in 
at least 63 percent of all platform removals for the foreseeable 
future. (See Appendix A of MMS (2005b)) for additional forecasting 
information).
    In addition to platform removals, based upon a review of the 
historical trends, industry projections, and recent forecast modeling, 
MMS estimates that between 170 and 273 explosive well-severance 
activities would occur annually over the next 5 years (see Table 7 in 
MMS, 2005a).

Description of Habitat and Marine Mammals Affected by the Activity

    The proposed explosive severance activities could occur in all 
water depths of the offshore areas designated by MMS as the GOM Central 
and Western Planning Areas (CPA and WPA) and a portion of the Eastern 
Planning Area (EPA) offered under Lease Sale 181/189 (see Figure 2 or 3 
in MMS, 2005a). Water depths in the areas of the proposed action range 
from 4 to 3,400 m (13-11,155 ft), with the majority of existing 
facilities and wells found within the CPA, concentrated on the upper 
shelf waters (greater than 200 m (656 ft) water depth) off of 
Louisiana. A detailed description of the northern GOM area and its 
associated marine mammals can be found in the MMS application and PEA 
and in a number of documents referenced in the application. Detailed 
information on the marine mammals in the GOM can also be found in the 
NMFS status of stocks reports (Waring et al., 2004) which is available 
for downloading or reading at: https://www.nefsc.noaa.gov/nefsc/
publications/tm/tm182/
 A total of 21 cetacean species and one species of sirenian (West 
Indian manatee) are known to occur in the GOM. These species are the 
sperm whale, pygmy sperm whale, dwarf sperm whale, Cuvier's beaked 
whale, Sowerby's beaked whale (extralimital), Gervais' beaked whale, 
Blainville's beaked whale, rough-toothed dolphin, bottlenose dolphin, 
pantropical spotted dolphin, Atlantic spotted dolphin, spinner dolphin, 
Clymene dolphin, striped dolphin, Fraser's dolphin, Risso's dolphin, 
melon-headed whale, pygmy killer whale, false killer whale, killer 
whale, short-finned pilot whale, North Atlantic right whale 
(extralimital), humpback whale (rare), minke whale (rare), Bryde's 
whale, sei whale (rare), fin whale (rare), and the blue whale 
(extralimital).
    A description of the status, distribution, and seasonal 
distribution of the affected species and stocks of marine mammals that 
might be affected by explosive severance activities is provided in MMS' 
application.

Potential Impacts to Marine Mammals

    Underwater explosions are the strongest manmade point sources of 
sound in the sea (Richardson et al., 1995). The underwater pressure 
signature of a detonating explosion is composed of an initial shock 
wave, followed by a succession of oscillating bubble pulses (if the 
explosion is deep enough not to vent through the surface) (Richardson 
et al., 1995). The shock wave is a compression wave that expands 
radially out from the detonation point of an explosion. Although the 
wave is initially supersonic, it is quickly reduced to a normal 
acoustic wave. The broadband source levels of charges weighing 0.5-20 
kg (1.1-44 lb) are in the range of 267-280 dB re 1 microPa (at a 
nominal 1-m distance), with dominant frequencies below 50 Hz 
(Richardson et al., 1995; CSA, 2004). The following sections discuss 
the potential impacts of underwater explosions on marine mammals, 
including mortality, injury, hearing effects, and behavioral effects.

Mortality or Injury

    It has been demonstrated that nearby underwater blasts can injure 
or kill marine mammals (Richardson et al., 1995). Injuries from high-
velocity underwater explosions result from two factors: (1) The very 
rapid rise time of the shock wave; and (2) the negative pressure wave 
generated by the collapsing bubble, which is followed by a series of 
decreasing positive and negative pressure pulses (CSA, 2004). The 
extent of injury largely depends on the intensity of the shock wave and 
the size and depth of the animal (Yelverton et al., 1973; Craig, 2001).
    The greatest damage occurs at boundaries between tissues of 
different densities because different velocities are imparted that can 
lead to their physical disruption; effects are generally greatest at 
the gas-liquid interface (Landsberg, 2000; CSA, 2004). Gas-containing 
organs, especially the lungs and gastrointestinal tract, are the most 
susceptible to this type of damage. Lung injuries (including 
lacerations and the rupture of the alveoli and blood vessels) can lead 
to hemorrhage, air embolisms, and breathing difficulties. The lungs and 
other gas-containing organs (nasal sacs, larynx, pharynx, and trachea) 
may also be damaged by compression/expansion caused by oscillations of 
the blast gas bubble (Reidenberg and Laitman, 2003). Intestinal walls 
can bruise or rupture, which may lead to hemorrhage and the release of 
gut contents. Less severe injuries include contusions, slight 
hemorrhaging, and petechia (Yelverton et al., 1973; CSA, 2004). Ears 
are the organs most sensitive to pressure and, therefore, to injury 
(Ketten, 2000; CSA, 2004). Severe

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damage to the ears can include rupture of the tympanic membrane, 
fracture of the ossicles, cochlear damage, hemorrhage, and 
cerebrospinal fluid leakage into the middle ear. By themselves, 
tympanic membrane rupture and blood in the middle ear can result in 
partial, permanent hearing loss. Permanent hearing loss can also occur 
when the hair cells are damaged by loud noises (ranging from single, 
very loud events to chronic exposure).

Hearing Effects

    Mammalian hearing functions over a wide range of sound intensities, 
or loudness. The sensation of loudness increases approximately as the 
logarithm of sound intensity (Richardson and Malme, 1993). Sound 
intensity is usually expressed in decibels (dB), units for expressing 
the relative intensity of sounds on a logarithmic scale. Because sound 
pressure is easier to measure than intensity and intensity is 
proportional to the square of sound pressure, sound pressure level is 
usually reported in units of decibels relative to a standard reference 
pressure.

Temporary Threshold Shift

    The mildest form of hearing damage, temporary threshold shift 
(TTS), is defined as the temporary elevation of the minimum hearing 
sensitivity threshold at particular frequency(s) (Kryter, 1985; CSA, 
2004). TTS may last from minutes to days. Although few data exist on 
the effects of underwater sound on marine mammal hearing, in 
terrestrial mammals, and presumably in marine mammals, received levels 
must exceed an animal's hearing threshold (i.e., maximum sensitivity) 
for TTS to occur (Richardson et al., 1995; Kastak et al., 1999; Wartzok 
and Ketten, 1999).
    Most studies involving marine mammals have measured exposure to 
noise in terms of sound pressure level (SPL), measured in dBrms 
or dBpeak pressure re 1 microPa. Exposure to underwater 
sound can also be expressed in terms of energy, also called sound 
exposure level (SEL), or acoustic energy (measured in dB re 1 
microPa\2\-s), which considers both intensity and duration of the 
sound. There appears to be a linear relationship between energy and the 
level of TTS, with duration and frequency seemingly unimportant (CSA, 
2004). If TTS is defined as a measurable threshold shift of 6 dB or 
more (Finneran et al., 2000, 2002), the onset of TTS (for white whales 
and bottlenose dolphins) was associated with an energy level of about 
184 dB re 1 microPa\2\-s (CSA, 2004). However, the data are very 
limited, and Finneran (2003) has noted that they should be interpreted 
with caution (CSA, 2004).

Permanent Threshold Shift (PTS)

    PTS is a permanent decrease in the functional sensitivity of an 
animal's hearing system at some or all frequencies (CSA, 2004). The 
principal factors involved in determining whether PTS will occur 
include sound impulse duration, peak amplitude, and rise time. The 
criteria are location and species-specific (Ketten, 1995) and are also 
influenced by the health of the receiver's ear.
    At least in terrestrial animals, it has been demonstrated that the 
received level from a single exposure must be far above the TTS 
threshold for there to be a risk of PTS (Kryter, 1985, Richardson et 
al., 1995; CSA, 2004). Sound signals with sharp rise times (e.g., from 
explosions) produce PTS at lower intensities than do other types of 
sound (Gisiner, 1998; CSA, 2004).
    For explosives, Ketten (1995) estimated that greater than 50-
percent PTS would occur at peak pressures of 237-248 dB re 1 microPa 
and that TTS would occur at 211-220 dB re 1 microPa. The ``safe'' peak 
pressure level to avoid physical injury recommended by Ketten (1995) is 
100 psi (237 dB re 1 microPa, or about 212 dB re 1 microPa\2\-s). PTS 
is assumed to occur at received levels 30 dB above TTS-inducing levels. 
Studies have shown that injuries at this level involve the loss of 
sensory hair cells (Ahroon et al., 1996; CSA, 2004).

Behavioral Effects

    Based on the information presented in Richardson et al. (1995), the 
possible behavioral effects of noise from underwater explosions on 
marine mammals may be categorized as follows:
    (1)The noise may be too weak to be heard at the location of the 
animal (i.e., below the local ambient noise level, below the hearing 
threshold of the animal at the relevant frequencies, or both);
    (2)The noise may be audible, but not loud enough to elicit an overt 
behavioral reaction;
    (3)The noise may elicit behavioral reactions, which may vary from 
subtle effects on respiration or other behaviors (detectable only 
statistically) to active avoidance behavior;
    (4)With repeated exposure, habituation (diminishing responsiveness) 
to the noise may occur. Continued disturbance effects are most likely 
with sounds that are highly variable in their characteristics, 
unpredictable in occurrence, and associated with situations perceived 
by the animal as threatening;
    (5) Any anthropogenic noise that is strong enough to be heard has 
the potential to reduce (mask) the ability of a marine mammal to hear 
natural sounds at similar frequencies, including calls from 
conspecifics, and underwater environmental sounds such as surf noise.
    (6) If mammals remain in an area because it is important for 
feeding, breeding or some other biologically important purpose even 
though there is chronic exposure to noise, it is possible that there 
could be noise-induced physiological stress; this might in turn have 
negative effects on the well-being or reproduction of the animals 
involved; and
    (7) Very strong sounds have the potential to cause temporary or 
permanent reduction in hearing sensitivity. In terrestrial mammals, and 
presumably marine mammals, received sound levels must far exceed the 
animal's hearing threshold for there to be any temporary threshold 
shift (TTS) in its hearing ability. For transient sounds, the sound 
level necessary to cause TTS is inversely related to the duration of 
the sound. Received sound levels must be even higher for there to be 
risk of permanent hearing impairment. In addition, intense acoustic or 
explosive events may cause trauma to tissues associated with organs 
vital for hearing, sound production, respiration and other functions. 
This trauma may include minor to severe hemorrhage.
    Behavioral reactions of marine mammals to sounds such as those 
produced by underwater explosives are difficult to predict. Whether and 
how an animal reacts to a given sound depends on factors such as the 
species, hearing acuity, state of maturity, experience, current 
activity, reproductive state, time of day, and weather. If a marine 
mammal reacts to a sound by changing its behavior or moving a short 
distance, the impacts may not be significant to the individual, stock, 
or species as a whole. However, if a sound displaces marine mammals 
from an important feeding or breeding area for a prolonged period, 
impacts could be significant (CSA, 2004).
    Richardson et al. (1995) summarized available information on the 
reported behavioral reactions of marine mammals to underwater 
explosions. Observations following the use of seal bombs as scare 
charges indicate that pinnipeds rapidly habituate to and, in general, 
appear quite tolerant of noise pulses from explosives. Klima et al. 
(1988) reported that small charges were not consistently effective in 
moving bottlenose dolphins away from blast sites in the GOM. Since

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dolphins may be attracted to the fish killed by such a charge, rather 
than repelled, scare charges are not used in the GOM platform removal 
program (G. Gitschlag, personal communication, in Richardson et al., 
1995).
    There are few data on the reactions of baleen whales to underwater 
explosions. Gray whales were apparently unaffected by 9- to 36-kg (20- 
to 97-lb) charges used for seismic exploration (Fitch and Young, 1948). 
However, Gilmore (1978) felt that similar underwater blasts within a 
few kilometers of the gray whale migration corridor did ``sometimes'' 
interrupt migration.
    Humpback whales have generally not been observed to exhibit 
behavioral reactions (including vocal ones) to explosions, even when 
close enough to suffer injury (hearing or other) (Payne and McVay, 
1971; Ketten et al., 1993; Lien et al., 1993; Ketten, 1995; Todd et 
al., 1996). In Newfoundland, humpbacks displayed no overt reactions 
within about 2 km of 200- to 2,000-kg explosions. Whether habituation 
and/or hearing damage occurred was unknown, but at least two whales 
were injured (and probably killed) (Ketten et al., 1993). Other 
humpback whales in Newfoundland, foraging in an area of explosive 
activity, showed little behavioral reaction to the detonations in terms 
of decreased residency, overall movements, or general behavior, 
although orientation ability appeared to be affected (Todd et al., 
1996). Todd et al. (1996) suggested caution in interpretation of the 
lack of visible reactions as indication that whales are not affected or 
harmed by an intense acoustic stimulus; both long- and short-term 
behavior as well as anatomical evidence should be examined. The 
researchers interpreted increased entrapment rate of humpback whales in 
nets as the whales being influenced by the long-term effects of 
exposure to deleterious levels of sound.
    As mentioned previously, Finneranet al. (2000) exposed captive 
bottlenose dolphins and belugas to single, simulated sounds of distant 
explosions. The broad-band received levels were 155-206 dB; pulse 
durations were 5.4-13 ms. This was equivalent to a maximum spectral 
density of 102-142 dB re 1 microPa\2\/Hz at a 6.1 Hz bandwidth. 
Although pulse durations differed, the source levels required to induce 
these reactions were similar to those found by Ridgway et al. (1997) 
and Schlundt et al. (2000).

Estimates of Take by Harassment During Explosive Severance Activities 
in the GOM

    The MMS has requested NMFS to issue authorizations, under section 
101(a)(5)(A) of the MMPA, to cover any potential take by Level A or 
Level B harassment for the 21 species of marine mammals listed 
previously in this document, incidental to the oil and gas industry 
conducting explosive-severance operations regulated by the MMS. 
Explosive severance operations have the potential to take marine 
mammals by contact with shock wave and acoustic energy released from 
underwater detonations and the resultant injury, hearing damage, and 
behavioral effects as defined by NMFS. For this activity, MMS has 
adopted, without modification, NMFS' take thresholds and criteria for 
explosives used in the incidental take authorization for shock trials 
for the U.S. Navy's Winston Churchill (USDON, 2001). While these 
criteria remain a subject for discussion (see 69 FR 21816, April 22, 
2004), the Churchill criteria (12 pounds/in\2\ (psi) peak-pressure and 
182 dB (re 1 microPa\2\-sec)) remain conservative because Finneran et 
al. (2003) did not find masked TTS in the single bottlenose dolphin 
tested at the highest exposure conditions: peak pressure of 207 kPa (30 
psi), 228 dB re 1 microPa pk-pk pressure, and 188 dB re 1 microPa\2\-s 
total energy flux.
    The criteria for nonlethal, injurious impacts (Level A harassment) 
are currently defined as the incidence of 50-percent tympanic-membrane 
(TM) rupture and the onset of slight lung hemorrhage for a 12.2-kg (27 
lb) dolphin calf. Level A harassment take is assumed to occur:
    1. At an energy flux density value of 1.17 in-lb/in\2\ (which is 
about 205 dB re 1 microPa\2\-s); and
    2. If the peak pressure exceeds 100 psi for an explosive source; 
i.e., the ``safe'' peak pressure level to avoid physical injury 
recommended by Ketten (1995).
    The horizontal distance from the explosive to each threshold is 
determined and the maximum distance at which either is exceeded is 
considered to be the distance at which Level A harassment would occur 
(USDON, 2001).
    NMFS recognizes two levels of noninjurious acoustical impacts 
(Level B harassment). One criterion for Level B harassment is defined 
by the onset of TTS. Two thresholds are applied. TTS is assumed to be 
induced:
    1. At received energies greater than 182 dB re 1 microPa\2\-s 
within any 1/3-octave band; and
    2. If, for an explosive source, the peak pressure at the animal 
exceeds 12 psi.
    As with Level A harassment, the horizontal distance to each 
threshold is determined and the maximum distance at which either is 
exceeded is considered the distance at which Level B harassment (TTS) 
would occur (USDON, 1998 and 2001; CSA, 2004).
    Sub-TTS behavioral effects may also be considered to constitute a 
take by Level B harassment if a marine mammal reacts to an activity in 
a manner that would disrupt some behavioral pattern in a biologically 
significant way. NMFS does not believe that single, minor reactions 
(such as startle or ``heads-up'' alert displays, short-term changes in 
breathing rates, or modified single dive sequences) that have no 
biological context qualify as takes (66 FR 22450, May 4, 2001). This 
would include minor or momentary strictly behavioral responses to 
single events such as underwater explosions. Since explosive severance 
activities result in single, almost instantaneous detonations, with no 
repetitive detonations, NMFS does not believe that marine mammals would 
be subject to behavioral harassment other than behavioral modifications 
incurred as a result of TTS.
    In order to obtain potential incidental-take numbers for explosive 
severance activities, fundamental modeling components require: (1) 
predictive modeling of detonation pressure/energy propagation, (2) 
propagation model verification and utilization, (3) predictive modeling 
of marine mammal take estimates, and (4) take-estimate calculation. 
These calculations are explained in detail in MMS' application and PEA.
    Based on MMS calculations for all explosive severance scenarios, 
Level A harassment takes would be limited to less than one bottlenose 
dolphin and between three and five bottlenose dolphins, one Atlantic 
spotted, and one pantropical spotted dolphins over the five-year period 
of the proposed regulations.
    Based on MMS calculations for all explosive severance scenarios, 
Level B harassment takes would be limited 148-227 bottlenose dolphins, 
35-65 Atlantic spotted dolphins, 33-77 pantropical spotted dolphins, 
11-27 Clymene dolphins, 8-12 rough-toothed dolphins, 6-14 striped 
dolphins, 6-15 melon-headed whales, 4-10 pilot whales, 2-5 spinner 
dolphins, 1-3 Risso's dolphins, and 1-2 sperm whales. It should be 
noted that these estimates are made without consideration of the 
implementation of mitigation measures to protect marine mammals, so 
actual harassment numbers would likely be

[[Page 49572]]

lower. Post-activity monitoring conducted by NMFS observers since about 
1989 has not resulted in any sightings of distressed marine mammals.

Mitigation and Monitoring

    Based upon the analysis found in the Structure-Removal PEA, MMS 
believes that implementation of the mitigation measures listed in this 
section will prevent any significant impacts from occurring.

Charge Criteria

    The charge criteria discussed here (e.g., charge size, detonation 
staggering, and explosive material) are applicable for all of the 
explosive-severance scenarios conducted under the proposed action.
Charge Size
    The options available under the multiple explosive-severance 
scenarios allow for the development of any size charge between 0 and 
500 lb (226.8 kg). Most often determined in the early planning stages, 
the final/actual charge weight establishes the specific mitigation 
scenario that must be adhered to as a permit condition. However, 
increasing charge size results in increasing levels of mitigation/
monitoring. Using explosives greater than 500 lb (226.8 kg) are not 
proposed to be authorized for taking marine mammals under the MMPA. Use 
of explosives greater than 500 lb (226.8 kg) would require additional 
National Environmental Policy Act (NEPA) analyses, Endangered Species 
Act (ESA) consultations and MMPA authorization prior to usage. As a 
result, no marine mammal takings will be authorized for charge weights 
greater than 500 lbs (226.8 kg).
Detonation Staggering
    Multiple-charge detonations will be staggered at an interval of 0.9 
sec (900 msec) between blasts to prevent an additive pressure event. 
For decommissioning purposes, a ``multiple-charge detonation'' refers 
to any configuration where more than one charge is required in a single 
detonation ``event.''
Explosive Material
    There are many important properties (i.e., velocity, brisance, 
specific-energy, etc.) related to the explosive material(s) used in 
developing severance charges. Material needs vary widely depending upon 
target characteristics, marine conditions, and charge placement. Since 
specific material and personnel safety requirements must be established 
and followed, MMS believes that all decisions on explosive composition, 
configuration, and usage should be made by the qualified (i.e., 
licensed and permitted) explosive contractors in accordance with the 
applicable explosive-related laws and regulations.

Specific Mitigation/Monitoring Requirements

    Explosive-severance activities, as described in the MMS application 
and PEA, have been grouped into five blasting categories (very small, 
small, standard, large, and specialty). Since the level of detonation 
pressure and energy is primarily related to the amount of the 
explosives used, these categories were developed cooperatively by MMS, 
NMFS and industry based upon the specific range of charge weights 
needed to conduct current and future GOM OCS decommissionings. 
Depending on the design of the target and other variable marine 
conditions, the severance charges developed under each of these 
categories could be designed for use in either a below-mudline (BML) or 
above mudline (AML) configuration. These factors, combined with an 
activity location within either the shelf (less than 200 m (656 ft)) or 
slope (greater than 200 m (656 ft)) species-delineation zone, result in 
20 separate severance scenarios, as shown in Table 1.

BILLING CODE 3510-22-S

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    The charge criteria listed previously will be standard for all 
decommissionings employing explosive-severance activities. However, 
depending upon the severance scenario, there are six different types of 
marine mammal/sea turtle monitoring surveys that could be conducted 
before and after all detonation events. The specific monitoring 
requirements, survey times, and impact zone radii for all explosive-
severance scenarios are summarized in Table 2.

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    Use of Table 2 is illustrated using the Standard Blasting Category 
for shelf and slope waters as an example:

Shelf Waters (<200 m): Scenarios C1 and C3

    An operator proposing shelf-based, explosive-severance activities 
conducted under the standard blasting category will be limited to 80-lb 
charge sizes (BML or AML) and will be required to conduct all requisite 
monitoring during daylight hours out to the associated impact-zone 
radii listed here:
    C1-631 m (2,069 ft)
    C3-829 m (2,721 ft)

Required Observers

    Generally, two NMFS observers are required to perform marine 
mammal/sea turtle detection surveys for standard-blasting under shelf 
scenarios C1 and C3. If necessary, the site coordinator will determine 
if additional observers are required to compensate for the complexity 
of severance activities and or structure configuration. In addition to 
meeting all reporting requirements, the NMFS observers will:
    (1) Brief affected crew and severance contractors on the monitoring 
requirements and notify topsides personnel to immediately report any 
sighted marine mammal/sea turtles to the observer or company 
representative;
    (2) Establish an active line of communication (i.e., 2-way radio, 
visual signals, etc.) with company and blasting personnel; and
    (3) Devote the entire, uninterrupted survey time to marine mammal/
sea turtle monitoring.

Pre-Detonation Monitoring

    Before severance charge detonation, the NMFS observers will conduct 
a 90-min surface monitoring survey of the impact zone. The monitoring 
will be conducted from the highest vantage point available from either 
the decommissioning target or proximal surface vessels. Once the 
surface monitoring is complete (i.e., the impact zone cleared of marine 
mammal/sea turtles), one of the NMFS observers will transfer to a 
helicopter to conduct a 30-min (Scenario C1) or 45-min (Scenario C3) 
aerial monitoring survey. As per approved guidelines, the helicopter 
will transverse the impact zone at low speed/altitude in a specified 
grid pattern. If during the aerial survey a marine mammal/sea turtle 
is:
    (1) Not sighted, proceed with the detonation;
    (2) Sighted outbound and continuously tracked clearing the impact 
zone, proceed with the detonation after the monitoring time is complete 
to ensure no reentry;
    (3) Sighted outbound and the marine mammal/sea turtle track is lost 
(e.g., the animal dives below the surface),
     Halt the detonation,
     Wait 30 min, and
     Reconduct the 30 min (C1) or 45 min (C3) aerial monitoring 
survey; or
    (4) Sighted inbound,
     Halt the detonation,
     Wait 30 minutes, and
     Reconduct the 30-min (C1) or 45-min (C3) aerial monitoring 
survey.

Post-Detonation Monitoring

    After severance charge detonation, the NMFS observer will conduct a 
30-min aerial monitoring survey of the impact zone to look for impacted 
marine mammal/sea turtles. If a marine mammal/sea turtle is found 
shocked, seriously injured, or dead, the operations will cease, 
attempts will be made, under the direction of the NMFS observer, to 
collect/resuscitate the animal, and the Southeast Region, NMFS will be 
contacted for additional instruction. If no marine mammal/sea turtles 
are observed to be impacted by the detonation, the NMFS observer will 
record all of the necessary information as required in MMS's permit 
approval letter and guidelines for the preparation of a trip report.
    If unforeseen conditions or events occur during a standard-blasting 
operation that may necessitate additional monitoring, the NMFS observer 
will contact the NMFS Platform Removal Observer Program (PROP) 
Coordinator in Galveston, TX and/or MMS for additional guidance. A 
flowchart of the monitoring process and associated survey times for 
standard severance-scenarios C1 and C3 is provided in Figure 6 in MMS, 
2005a.

Slope Waters (>200 m): Scenarios C2 and C4

    An operator proposing slope-based, explosive-severance activities 
conduced under the standard blasting category will be limited to 80-lb 
charge sizes (BML or AML) and conduct all requisite monitoring during 
daylight hours out to the associated impact-zone radii listed below:
    C2-631 m (2,069 ft)
    C4-829 m (2,721 ft)

Required Observers

    Slope water scenarios propose to require a minimum of three NMFS 
observers for the coordinated surface, aerial, and acoustic monitoring 
surveys, therefore, at least two ``teams'' of observers will be 
required. The PROP Coordinator will determine each ``team'' size 
depending upon the complexity of severance activities and or structure 
configuration. In addition to meeting all reporting requirements, the 
NMFS observers would perform the same functions as the observers in the 
Shelf Water Scenarios C1 and C3.

Pre-Detonation Monitoring

    Before severance charge detonation, NMFS observers will begin a 90-
min surface monitoring survey and a 120-min (Scenario C2) or 150-min 
(Scenario C4) passive-acoustic monitoring survey of the impact zone. 
The surface monitoring will be conducted in the same manner as the C1 
and C3 scenarios. Once the surface monitoring is complete (i.e., the 
impact zone cleared of marine mammal/sea turtles), the acoustic survey 
will continue while one of the NMFS observers transfers to a helicopter 
to conduct a 30-min (Scenario C2) or 60-min (Scenario C4) aerial 
monitoring survey. As per approved guidelines, the helicopter will 
transverse the impact zone at low speed/altitude in a specified grid 
pattern.
    The proposed requirements on marine mammal and sea turtle sighting 
for the C1 and C3 scenarios would apply here except that the wait times 
and aeries survey times differ (see Table 2).

Post-Detonation Monitoring

    Scenarios C2 and C4 both would require the same post-detonation 
monitoring explained for the C1 and C3 scenarios. , or
    Scenario C4 also requires a post-post-detonation aerial monitoring 
survey to be conducted within 2-7 days after detonation activities 
conclude. Conducted by helicopter or fixed-wing aircraft, observations 
are to start at the removal site and proceed leeward and outward of 
wind and current movement. Any injured or killed marine mammal/sea 
turtle must be recorded, and if possible, tracked after notifying NMFS. 
If no marine mammal/sea turtles are observed to be impacted during 
either aerial survey, the NMFS observers will record all of the 
necessary information as detailed in MMS's permit approval letter and 
guidelines for the preparation of a trip report.
    If unforeseen conditions or events occur during a standard-blasting 
operation that may necessitate additional monitoring, the NMFS observer 
will contact the coordinator and/or MMS for additional guidance. A 
flowchart of the monitoring process and associated survey times for 
standard severance- scenarios C2 and C4 is

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provided in Figure 7 in the MMS application (MMS, 2005a).

Reporting Requirements

    All explosive-severance activities in the GOM would be mandated to 
abide by the reporting requirements listed in this section. The 
information collected will be used by MMS and NMFS to continually 
assess mitigation effectiveness and the level of marine mammal/sea 
turtle impacts.
    The reporting responsibilities will be undertaken by the NMFS' 
marine mammal/sea turtle observer for scenarios B1-E4 (Table 2) and the 
collected data will be prepared and routed in accordance with 
previously established guidelines for filing times and distribution.
    For very-small blasting scenarios A1-A4, the company observer will 
be responsible for recording the data and preparing a trip report for 
submittal within 30-days of completion of the severance activities. 
Trip reports for scenarios A1-A4 will be sent to MMS and NMFS Gulf/
Southeast regional offices.
    In addition to basic operational data (i.e., area and block, water 
depth, company/platform information, etc.), the trip reports must 
contain all of the applicable information listed in Table 10 in MMS' 
application. In the event that a marine mammal or sea turtle is 
shocked, injured, or killed during the severance activities, the 
operations will cease and the observer will contact MMS and NMFS' 
Southeast Regional Office. If the animal does not revive, efforts 
should be made to recover it for necropsy in consultation with the 
appropriate NMFS' Stranding Coordinator.

Conclusions

    MMS has concluded that impacts to marine mammals from explosive-
severance activities conducted under the proposed action are 
potentially adverse but not significant. The projected Level A 
harassment takes are very unlikely and, would be limited to 3 species. 
No deaths or serious injuries to marine mammals or sea turtles are 
projected. If any marine mammals are displaced from preferred grounds, 
it will be for the short term, and no critical habitat is involved. 
Level B harassment takes may disrupt behavioral patterns in a few 
individuals of a few species, but no effect is projected on annual 
recruitment or survival. With proposed mitigation measures in place, 
the potential impacts on marine mammals are expected to be negligible.

ESA

    Under section 7 of the ESA, MMS has begun consultation on the 
proposed explosive severance activtiy. NMFS will also consult on the 
issuance of regulations and LOAs under section 101(a)(5)(A) of the MMPA 
for this activity. Consultation will be concluded prior to a 
determination on the issuance of regulations.

NEPA

    MMS completed and released its PEA to the public on February 28, 
2005. That document is available for review (see ADDRESSES).
    NMFS is reviewing the PEA and will either adopt it or prepare its 
own NEPA document before making a determination on the issuance of 
regulations and LOAs for this activity.

Information Solicited

    NMFS requests interested persons to submit comments and information 
concerning this request (see ADDRESSES). NMFS requests commenters also 
read the MMS application and PEA on this action prior to submitting 
comments.

    Dated: August 18, 2005.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 05-16843 Filed 8-23-05; 8:45 am]
BILLING CODE 3510-22-S