OCS Study 

MMS 2003-070 

 

Explosive Removal of Offshore Structures 

Information Synthesis Report 

U.S. Department of the Interior

Minerals Management Service 

Gulf of Mexico OCS Region 
U.S. Department of the Interior

Minerals Management Service 

Gulf of Mexico OCS Region 

OCS Study 

MMS 2003-070 

Explosive Removal of Offshore Structures 

Information Synthesis Report 

Preparer 

Continental Shelf Associates, Inc. 

Prepared under MMS Contract 

1435-01-02-CT-85237 

by 

Continental Shelf Associates, Inc. 

759 Parkway Street 

Jupiter, Florida 33477 

Published by 

New Orleans

March 2004 
iii 

DISCLAIMER 

This report was prepared under contract between the Minerals Management Service 

(MMS) and Continental Shelf Associates, Inc. (CSA). This report has been technically 

reviewed by the MMS, and it has been approved for publication. Approval does not 

signify that the contents necessarily reflect the views and policies of the MMS, nor does 

mention of trade names or commercial products constitute endorsement or 

recommendation for use. It is, however, exempt from review and compliance with MMS 

editorial standards. 

REPORT AVAILABILITY 

Extra copies of this report may be obtained from the Public Information Office (Mail 

Stop 5034) at the following address: 

 U.S. Department of the Interior 

 Minerals Management Service 

 Gulf of Mexico OCS Region 

 Public Information Office (MS 5034) 

 1201 Elmwood Park Boulevard 

 New Orleans, Louisiana 70123-2394 

 Telephone: (504) 736-2519 or 

 1-800-200-GULF 

CITATION

Suggested citation: 

Continental Shelf Associates, Inc. 2004. Explosive removal of offshore structures - 

information synthesis report. U.S. Department of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Study MMS 2003-070. 181 pp. + app. 
v 

TABLE OF CONTENTS 

Page 

List of Figures.................................................................................................................... ix 

List of Tables ..................................................................................................................... xi 

List of Acronyms ............................................................................................................. xiii 

Chapter 1 – Executive Summary .........................................................................................1 

ES-1 Background, Objectives, and Study Methods..............................................1 

ES-2 Decommissioning and Explosive Removal Methods ..................................2 

ES-3 Sound Metrics and Injury-Mortality Criteria...............................................3 

ES-4 Affected Environment..................................................................................5 

ES-5 Discussion and Recommendations ..............................................................7 

ES-6 Conclusions................................................................................................12 

Chapter 2 – Introduction ....................................................................................................15 

2.1 MMS Mission and Regulations .................................................................15 

2.1.1 ESA Consultation and Related Requirements ...............................25 

2.1.2 MMPA Concerns ...........................................................................26 

2.2 Study Purpose and Objectives ...................................................................27 

2.3 Project Team ..............................................................................................27 

2.4 Study Methods and Report Organization...................................................28 

2.4.1 Task 1 – Information Search/Collection and Data 

Management...................................................................................28 

2.4.2 Task 2 – Information Synthesis Report .........................................31 

Chapter 3 – Decommissioning and Explosive Removal Methods.....................................33 

3.1 Background................................................................................................33 

3.2 Presently Employed Explosive Cutting Techniques..................................34 

3.2.1 Bulk Explosive Charges.................................................................34 

3.2.2 Configured Bulk Charges ..............................................................34 

3.2.3 Cutting Charges .............................................................................37 

3.3 Potential Future Explosive Cutting Techniques ........................................42 

3.3.1 Contact Plaster Charges .................................................................42 

3.3.2 Shock-Wave Focusing Charges .....................................................42 

3.3.3 Radial Hollow Charges..................................................................45 

3.4 Characteristics and Physical Properties of Various Explosives.................45 

3.5 Developing Technologies ..........................................................................45 

3.5.1 Improved Explosives .....................................................................45 

3.5.2 Improved Shaped Charges .............................................................45 

3.5.3 Improved Charge Deployment Devices.........................................52 

3.5.4 Computer Modeling.......................................................................52 

3.5.5 Improvements in Explosive Cutting Tape .....................................52 

3.5.6 Fracturing Charges.........................................................................52 

3.5.7 Shock-wave Focusing Charges......................................................52 

3.5.8 Radial Hollow Charges..................................................................52 
TABLE OF CONTENTS 

(continued) 

Page 

vi 

Chapter 4 – Physics of Underwater Explosions.................................................................53 

4.1 Underwater Explosive Source Characteristics...........................................53 

4.1.1 Explosive Process ..........................................................................53 

4.1.2 Shaped Charges and Directionality................................................54 

4.1.3 Media Considerations ....................................................................55 

4.1.4 Multiple Charges............................................................................57 

4.2 Shock Wave and Acoustic Propagation.....................................................58 

4.2.1 Pressure Waveform........................................................................58 

4.2.2 The Near-Field...............................................................................58 

4.2.3 Sea Surface Reflections .................................................................60 

4.2.4 Sea Bottom Reflections..................................................................61 

4.2.5 Long-Range Propagation ...............................................................61 

4.3 Sound Metrics and Injury-Mortality Criteria.............................................63 

4.3.1 Metrics ...........................................................................................63 

4.3.2 Decibels..........................................................................................65 

4.3.3 Frequency Content.........................................................................65 

4.3.4 dBht(Species)..................................................................................66 

4.3.5 Impulse...........................................................................................67 

4.3.6 Root-Mean-Square Levels .............................................................68 

4.4 Data Gaps and Recommended Areas of Future Research .........................69 

Chapter 5 – Affected Environment....................................................................................71 

5.1 Marine Fishes.............................................................................................71 

5.1.1 Gulf of Mexico OCS Region .........................................................71 

5.1.2 Pacific OCS Region .......................................................................73 

5.1.3 Alaska OCS Region .......................................................................77 

5.2 Marine Turtles............................................................................................78 

5.2.1 Marine Turtles of North America ..................................................78 

5.2.2 Distributions of Marine Turtles and Their Association with 

Offshore Oil and Gas Structures....................................................81 

5.2.3 Distributions of Marine Turtle Species Within MMS OCS 

Planning Areas...............................................................................82 

5.3 Marine Mammals.......................................................................................83 

5.3.1 Gulf of Mexico OCS Region .........................................................83 

5.3.2 Pacific OCS Region .......................................................................87 

5.3.3 Alaska OCS Region .......................................................................94 

5.3.4 Marine Mammal Survey Data Limitations ....................................96 
TABLE OF CONTENTS 

(continued) 

Page 

vii 

Chapter 6 – Environmental Consequences ........................................................................97 

6.1 Marine Fishes.............................................................................................97 

6.1.1 Lethal Effects of Underwater Explosions on Fishes......................98 

6.1.2 Sublethal Effects ..........................................................................104 

6.1.3 Prediction of Lethal Range ..........................................................105 

6.2 Marine Turtles..........................................................................................109 

6.2.1 Physical Effects of Underwater Explosions.................................109 

6.2.2 Observations of Marine Turtles Injured or Killed by 

Underwater Explosives ................................................................112 

6.3 Marine Mammals.....................................................................................116 

6.3.1 Zones of Influence .......................................................................117 

6.3.2 Hearing in Marine Mammals.......................................................117 

6.3.3 Mechanisms of Injury ..................................................................121 

6.3.4 Review of the Documented Effects of Explosives on 

Marine Mammals.........................................................................123 

6.4 Data Gaps and Recommended Areas of Future Research .......................143 

6.4.1 Marine Fishes...............................................................................143 

6.4.2 Marine Turtles..............................................................................143 

6.4.3 Marine Mammals.........................................................................144 

Chapter 7 – Mitigation and Monitoring...........................................................................147 

7.1 Marine Fishes...........................................................................................147 

7.2 Marine Turtles..........................................................................................148 

7.3 Marine Mammals.....................................................................................151 

Chapter 8 – Discussion and Recommendations...............................................................155 

8.1 Fishes .......................................................................................................156 

8.2 Sea Turtles ...............................................................................................156 

8.3 Marine Mammals.....................................................................................157 

8.4 Physics of Underwater Detonations.........................................................159 

Chapter 9 – Conclusions ..................................................................................................161 

Chapter 10 – Literature Cited ..........................................................................................163 

Appendix – Bibliographic Database ............................................................................... A-1 
ix 

LIST OF FIGURES 

Figure Page

 2.1 Profile diagram showing the major components of a representative fixed 

oil and gas platform ............................................................................................16 

 3.1 Bulk explosive charge.........................................................................................35 

 3.2 Bulk charge arrangement for larger diameters....................................................36 

 3.3 Configured bulk “ring charge”............................................................................38 

 3.4 Focusing charge. .................................................................................................39 

 3.5 External linear-shaped charge.............................................................................40 

 3.6 Internal linear-shaped charge..............................................................................41 

 3.7 Flexible linear-shaped charge .............................................................................43 

 3.8 Shock-wave focusing charge ..............................................................................44 

 3.9 Schematic of a radial hollow charge...................................................................46 

 3.10 Radial hollow charges arranged for cutting a leg from outside..........................47 

 4.1 Pressure waveform from a 0.82 kg SUS charge detonated at 193 m..................59 

 4.2 Pressure waveform for 0.82 kg SUS charge detonated at 23 m..........................60 

 4.3 Example sound field calculations produced using the parabolic equation 

finite difference propagation model....................................................................63 

 4.4 Transient pressure signal and corresponding cumulative energy density 

function ...............................................................................................................68 

 6.1 Response of fish to underwater blast as a function of impulse strength 

and body weight................................................................................................100 

 6.2 Schematic representation of the zones of potential influence of 

anthropogenic sounds on marine mammals......................................................118 

 6.3 Underwater audiograms of selected toothed whale species, showing the 

minimum detectable sound level for tonal sounds at various frequencies........119 
LIST OF FIGURES 

(continued) 

Figure Page

x 

 6.4 Energy levels (dB re 1 μPa2-s) of underwater sound that have resulted in 

temporary threshold shift in odontocetes (red squares) and pinnipeds 

(blue rectangle) .................................................................................................128 

 6.5 Average threshold shift experienced by and average amount of energy to 

which bottlenose dolphins and white whales were exposed in the 

experiments described in the text......................................................................129 
xi 

LIST OF TABLES 

Table Page 

ES.1 Types and Amounts of Data Available Regarding Impacts of Underwater 

Detonations on Marine Fishes, Marine Turtles, and Marine Mammals ............8 

 2.1 Summary of Minerals Management Service (MMS) Regulatory 

Requirements Relevant to the Decommissioning of Outer Continental 

Shelf (OCS) Oil and Gas Facilities, as Codified in 30 CFR Part 250 .............18 

 2.2 Summary of Pertinent Requirements for Platform and Other Facility 

Removal from the Outer Continental Shelf (OCS), Per Updated 

Regulations ......................................................................................................20 

 2.3 Summary of Reporting Requirements, Per Updated Decommissioning 

Regulations ......................................................................................................24 

 3.1 Physical Properties of Some of the More Commonly Used Explosives..........48 

 4.1 Acoustic Propagation Modeling Approaches and Their Respective 

Advantages and Disadvantages........................................................................62 

 5.1 Reef Fishes That Associate with Oil and Gas Structures in the Gulf of 

Mexico .............................................................................................................72 

 5.2 Pelagic Species That Associate with Oil and Gas Structures in the Gulf 

of Mexico.........................................................................................................74 

 5.3 Fish Species Associated with Oil and Gas Platforms in Santa Barbara 

Channel ............................................................................................................75 

 5.4 Managed Fish Species Found in Lower Cook Inlet, Alaska............................77 

 5.5 Marine Turtle Species Within Minerals Management Service Gulf of 

Mexico (GOM), Pacific, and Alaska Outer Continental Shelf (OCS) 

Planning Areas.................................................................................................82 

 5.6 Abundance, Protective Status (Under the Endangered Species Act), 

Habitat Characteristics, Group Size, and Dive Characteristics of 

Marine Mammals That are Known to (or May) Occur in the Northern 

Gulf of Mexico.................................................................................................84 

 5.7 Common and Scientific Names, Abundance, Status, and Seasonal 

Occurrence of Cetaceans That May Occur in the Southern California 

Bight.................................................................................................................88 
LIST OF TABLES 

(continued) 

Table Page 

xii 

 5.8 Common and Scientific Names, Abundance, Status, and Seasonal 

Occurrence of Pinniped Species and the Southern Sea Otter (Mustelid) 

Present in the Southern California Bight .........................................................92 

 6.1 Estimated Number of Dead Fishes Floating at the Surface After 

Detonations During 1986 to 1998..................................................................102 

 6.2 Factors That Can Affect Fish Mortality, Making Precise Predictions of 

Mortality Difficult..........................................................................................106 

 6.3 Estimated Safe Range for Select Reef and Coastal Pelagic Species. ............108 

 6.4 Underwater Explosion Effects on Marine Turtles Reported by 

O'Keeffe and Young (1984) and Klima et al. (1988) ....................................114 

 6.5 Impulses in Pascal-Seconds Needed to Cause Injury to Various 

Species of Marine Mammals at the Water Surface, According to 

Yelverton’s (1981) Equations........................................................................135 

 6.6 Distances in Meters to Impulses Causing No Injury, 1% Mortality, and 

50% Mortality ................................................................................................136 

 6.7 Impulses Causing Various Degrees of Injury Computed According to 

the Method of Craig (2001) ...........................................................................138 

 6.8 Impulses Required to Cause Various Levels of Injury to a Dolphin 

Calf and Slight Injury to a 0.2-kg Marine Mammal, as a Function of 

Depth..............................................................................................................139 

 7.1 Summary of the National Marine Fisheries Service “Generic” 

Incidental Take Statement Regarding the Protection of Marine Turtles 

Prior to and During the Explosive Removal of Offshore Structures .............149 

 7.2 Marine Turtles Impacted from Explosive Structure Removals from 

1987 to May 2003 ..........................................................................................149 

 8.1 Types and Amounts of Data Available Regarding Impacts of 

Underwater Detonations on Fishes, Sea Turtles, and Marine Mammals.......155 
xiii

LIST OF ACRONYMS

ABR auditory brainstem response

ANFO ammonium nitrate with fuel oil

AUV autonomous underwater vehicle

CFR Code of Federal Regulations

CSA Continental Shelf Associates, Inc.

EA Environmental Assessment

EFD energy flux density

EIS Environmental Impact Statement

ER Environmental Report

ESA Endangered Species Act

FAD fish attraction device

LOA Letter of Authorization

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

NEPA National Environmental Policy Act

NMFS National Marine Fisheries Service

NOAA-F National Oceanic and Atmospheric Administration – Fisheries Division

NTL Notice to Lessees

OCS outer continental shelf

ONR Office of Naval Research

PBI primary blast injury

PI Principal Investigator

PTS permanent threshold shift

QRB Quality Review Board

RDX cyclonite

RL received level

rms root-mean-square

ROV remotely operated vehicle

SEL sound exposure level

SL source level

SPL sound pressure level

TL transmission loss

TNT trinitrotoluene

TTS temporary threshold shift
1

CHAPTER 1

EXECUTIVE SUMMARY

ES-1 Background, Objectives, and Study Methods

Nearly 4,000 oil and gas structures currently exist in Federal waters of the U.S.

outer continental shelf (OCS), with the vast majority present in the Gulf of Mexico. The

primary purpose of these structures (e.g., fixed platforms) is to develop and produce oil,

natural gas, and gas condensates from offshore hydrocarbon reservoirs. When offshore

production from a producing field becomes uneconomic, the lease(s) may be terminated

by the operator. As one of its lease conditions, the Minerals Management Service

(MMS) requires that operators (responsible for installation and operation of a platform)

subsequently remove the structure within a year of lease termination.

Offshore structure (e.g., platform) removal typically involves the use of

explosives to sever structure-associated components requiring removal – wellheads, piles,

etc. – several feet below the seafloor. Historically, offshore development and production

of oil and gas reserves has occurred in shelf waters (i.e., <200 m). Movement of

production platforms farther offshore, coupled with recent interest in deepwater

development, however, has raised the issue of future platform removal in deeper OCS

waters (e.g., over the continental slope). Further, the presence of listed (i.e., endangered

or threatened species listed or proposed for listing under the Endangered Species Act

[ESA]) and/or protected species (i.e., all marine mammals are protected under the Marine

Mammal Protection Act [MMPA]) in marine waters, coupled with the mandate to

minimize or eliminate the potential for impact to these species, underscores the need to

fully understand the environmental impacts associated with explosive platform removal.

The focus of the present study was to collect and synthesize existing information

relevant to explosive removal of offshore structures in aquatic environments. While the

expected application of this knowledge may include U.S. waters (e.g., Gulf of Mexico,

California, and Alaska OCS), the scope of this effort is worldwide. Sensitive marine

resources considered in this analysis include marine fishes, marine turtles, and marine

mammals. The primary study objectives were to:

1) provide a summary of available information by topic;

2) identify information and data gaps that could be filled by subsequent research

activities; and

3) recommend areas of research to meet MMS information needs.

The study effort was divided into two separate tasks – to develop the information

synthesis report, and to create a separate electronic database of all identified data sources.

Information gathered included pertinent data sources in the following topics:

• Explosive Removal Methods;

• Physics of Underwater Explosions;
2

• Biological Resources;

• Impacts to Biological Resources; and

• Mitigation and Monitoring of Effects.

Information was gathered via electronic database searches (e.g., via DIALOG

Information Retrieval Service; access to 14 separate databases) and review of corporate

and personal libraries of project Principal Investigators, and included data sources from

the peer-reviewed literature, conference and workshop proceedings, contract reports, and

the gray literature.

ES-2 Decommissioning and Explosive Removal Methods

To remove a fixed platform, the installation steps are essentially reversed.

Topside equipment such as living quarters, generators, and processing equipment is taken

off by crane and returned to shore for scrap or to be reused. The deck sections are then

lifted from the platform and placed on cargo barges for transportation to their disposal

site. Conductors, flare piles, well conductors, submerged wells, and caissons are

structures subject to explosive removal. MMS regulations require that the piles and well

conductors be severed at least 5 m (15 ft) below the mud line and removed.

Pilings and conductors can be cut manually by a number of mechanical means

including:

• use of tungsten-carbide blade cutters contained in routine rig workover

equipment;

• use of diamond wire and hydraulic shear cutters deployed by remotely

operated vehicles (ROVs); and

• manually by divers through the use of mechanical or abrasive cutting

techniques.

The safest and easiest cutting procedure is to place an explosive charge inside the

piling at the desired depth and sever the piling explosively. Presently employed

explosive cutting techniques include the following:

• Bulk Explosive Charges – the most commonly used technique for explosive

cutting of piles and conductors; comprising C-4 or Comp B explosives;

explosives are castable and moldable, have a high velocity on detonation and

a high shattering power, and are not as dangerous to handle as some other

types of high explosives. Bulk charges are lowered into prepared pilings or

well conductors and detonated nearly simultaneously with a 0.9-sec delay in

groups of eight or less. Bulk explosives have a 95% success rate when sized

properly. Increased water depth has no adverse impact on the success rate of

bulk explosive cuts.
3

• Configured Bulk Charges – configured bulk charges such as “ring charges”

and “focusing” charges are designed to collide or “focus” the detonation front

to concentrate more energy along the fracture line, and thus reduce the size of

the charge needed to cut a piling. These types of charges have been effective

in reducing “belling” or bulging out of the severed piling.

• Cutting Charges – cutting charges include linear-shaped charges and “cutting

tape.” Linear-shaped charges use high-velocity explosive energy to accelerate

a v-shaped band of cutting material, usually copper, in a high velocity jet that

penetrates through the steel of the piling. Explosive cutting tape is a flexible

version of the linear-shaped charge.

A series of potential future explosive cutting techniques also was evaluated,

including contact plaster charges, shock-wave focusing charges, and radial hollow

charges.

Underwater explosive source characteristics were detailed, including the physics

of the explosive process, the use of shaped charges and associated directionality of the

explosive-based shock wave, media considerations (e.g., open water detonation), the use

of multiple charges, and shock waves and acoustic propagation.

ES-3 Sound Metrics and Injury-Mortality Criteria

Metrics

Sound level metrics are parameters that quantitatively describe the characteristics

of sound pressure waves at a given spatial location. The commonly used metrics for

impulsive sounds describe the amplitude, energy, and time-related characteristics of the

pressure wave. The values of specific metrics are used to gauge the degree of impact that

underwater sound signals have on marine wildlife. Standard thresholds for the metrics

have been established in reference to the minimum levels at which specific impacts have

been observed to occur for a given species.

The metrics that need to be considered for gauging one type of impact may differ

from the metrics used for another type of impact. The most common metrics for

impulsive sounds are as follows:

• Peak Pressure – The highest pressure attained by a sound pressure signal. This

pressure is measured with respect to ambient pressure, and is also referred to

as zero-to-peak pressure.

• Peak-to-peak Pressure – The difference between the highest pressure and

lowest pressure over the duration of a waveform. For impulsive sounds

produced by blasting, the lowest pressure is generally negative with respect to

ambient pressure and occurs soon after the largest positive peak due to

expansion imparted to the water by its positive impulse.

• Impulse – The time integral of pressure through the largest positive phase of a

pressure waveform. It has units of Pascal seconds.
4

• Root-mean-square (rms) – The square root of the mean square pressure over

the duration of the impulsive waveform. The duration used strongly

influences the value of this metric, though its definition is sometimes quite

ambiguous. Recent methods have been proposed for determining the duration

based on the cumulative energy flux density function.

• Energy Flux Density (EFD) – The total acoustic energy propagated through a

unit area normal to the direction of propagation. The EFD of plane waves can

be computed as the time integral of squared pressure, divided by the acoustic

impedance of the medium. The EFD is not suitable for continuous-wave

sounds because the integral is not normalized in time. The EFD has units of

Joules/m2, but is commonly expressed in decibels (dB).

• Sound Exposure Level (SEL) – The time integral of square pressure divided

by the product of sound speed and water density. The sound exposure level is

commonly expressed in decibels.

Decibels

All of the above metrics, except for impulse, are normally expressed in decibels.

The decibel presents pressure values on a logarithmic scale relative to a pre-defined

reference level. The EFD and SEL metrics are converted to decibels in a slightly

different way. It is noteworthy that these metrics often are used to refer to the same

quantity, namely, the time integral of square pressure divided by the product of sound

speed and density. This definition for EFD, however, is not strictly correct for complex

pressure fields; SEL may be a more appropriate metric in an analysis of potential impacts

from explosive sources.

Frequency Content

None of the above metrics directly provides information about the spectral energy

content of the sound signal. Spectral content is important for some types of impact

criteria (e.g., the accepted threshold level for temporary threshold shift [TTS] is based on

exceeding EFD levels of 182 dB re μPa2

s in any 1/3-octave frequency band). The

standard approach in this case is to apply frequency domain filtering to the pressure

waveform prior to computation of the threshold. This approach is recommended only for

the EFD (or SEL) and rms metrics. A modified version of the peak pressure metric also

has been developed that accounts for the frequency-dependent hearing sensitivities of

specific species – identified as dBht(Species).

dBht(Species)

As a means of assessing potential injury from acoustic sources, the concept of

dBht(Species) was summarized. The dBht(Species) metric expresses sound pressure levels

relative to the hearing thresholds of specific species. It is used most commonly for

gauging impacts of continuous sounds, although it may also be applicable for impulsive

noise. This metric is based on the same principle as frequency weighting schemes used

for determining impacts of noise on humans. Measurements of hearing sensitivity versus

frequency for individual species, known as audiograms, have been measured for many
5

species of fish and a limited number of whales. Confidence in the accuracy of

audiograms for most marine species is, however, limited at the present due to the small

number of individuals upon which these measurements have been performed.

Impulse

Impulse is defined by the time-integral of pressure through the waveform. The

impulse for exponentially decaying shock pulses from underwater explosives (assuming

no interference with surface or bottom reflections) is given by a simple expression.

However, for shallow sources or receivers, the arrival of the surface reflection has the

effect of canceling later parts of the pressure pulse. Consequently, impulse calculations

are often performed by integrating the direct path pressure only up to the arrival time of

the surface reflection.

Root-Mean-Square Levels

The rms sound level metric has gained popularity because it gives the most

representative measure of the average effective amplitude over a transient signal’s

duration. This metric is especially well suited to characterizing sonar pings and signals

such as windowed sine pulses. It also is quite widely applied for estimating impacts of

impulsive airgun noise on marine mammals. The rms metric is computed as the square

root of the mean squared pressure over the signal's “duration,” the definition of which is

somewhat ambiguous.

ES-4 Affected Environment

The affected environment discussion considers those components of the

biological environment that are at the greatest risk of impact from explosive platform

removal – marine fishes, marine turtles, and marine mammals. In the development of

this text, emphasis has been placed on the presence and characteristics of species present

in U.S. waters. Particular emphasis has been placed on listed and/or protected species –

those protected under the ESA and MMPA, respectively.

Marine Fishes

In the three OCS regions (i.e., Gulf of Mexico, Pacific, and Alaska), large

numbers of fishes associate with oil and gas structures. These fishes are briefly

characterized, with emphasis on federally managed species. Major findings pertinent to

marine fishes, by region, include:

• Gulf of Mexico OCS – reef and pelagic fishes that associate with oil and gas

platforms are broadly classified into coastal, offshore, and bluewater

assemblages.

• Pacific OCS – fishes that associate with offshore oil and gas structures and are

generally classified as groundfishes, including >70 species, most of which are

rockfishes.
6

• Alaska OCS – no information on platform-associated fishes was identified for

the primary offshore oil and gas field – Cook Inlet. Other platforms and

structures in the Beaufort Sea are built upon large gravel causeways or berms

and will not be removed with explosives.

Marine Turtles

Seven marine turtle species were considered in this analysis. Six species are

listed as either endangered or threatened under the ESA (i.e., loggerhead, green,

hawksbill, Kemp’s ridley, Pacific [olive] ridley, and leatherback), while the seventh (i.e.,

black turtle) is currently unlisted. The distribution of marine turtles species within MMS

OCS Planning Areas is variable. Two marine turtle species – loggerheads and

leatherbacks – are known from all three regions (Gulf of Mexico, Pacific, Alaska), and

are the only marine turtle species present in Alaska waters. Remaining species are found

exclusively in their respective regions, including green, hawksbill, and Kemp's ridley in

the Gulf of Mexico region, and black and Pacific (olive) ridley in the Pacific region.

Marine Mammals

Marine mammal summaries were organized by OCS Region – Gulf of Mexico,

Pacific, and Alaska. Marine mammal data have been compiled and summarized based on

both historical and recent aerial and/or shipboard surveys, with the focus placed on those

areas within each region where oil and gas platforms or other OCS facilities have been

placed and will require removal.

All marine mammals are protected by Federal law (MMPA), which affords

individuals and populations from mortality, injury, or harassment. Under MMPA, a

species may be designated as a depleted or strategic stock. In addition, individual species

also may be designated as threatened or endangered under the ESA. A stock may be

classified as threatened or endangered, depleted, and strategic simultaneously.

In the Gulf of Mexico, toothed whales are by far the most abundant marine

mammals present. No pinnipeds are found in the Gulf of Mexico, and Bryde’s whale is

the only mysticete that is seen with any regularity. Sixteen species are routinely sighted

in the Gulf of Mexico, and most are year-round residents. Bottlenose dolphins and

Atlantic spotted dolphins are by far the dominant species of the continental shelf and

shelf edge. Bottlenose dolphins also can range onto the continental slope in the northeast

Gulf. The most abundant species in deep water are Stenella spp. dolphins. Bryde’s

whales have been found in the northeastern Gulf along the 100-m contour.

In the Pacific OCS, numerous marine mammal species are resident or transitory.

Thirty-three species of cetaceans may occur in the Southern California Bight, including

25 species of toothed whales and 8 species of baleen whales. Common toothed whale

species include Dall’s porpoise, Pacific white-sided dolphin, Risso’s dolphin,

short-beaked common dolphin, northern right whale dolphin, and gray whale. Other

species occur in relatively moderate or small numbers or are only occasionally sighted.
7

ESA-listed species off southern California include sperm, northern right,

humpback, blue, fin and Sei whales. Six species of pinnipeds may also occur in southern

California waters (i.e., harbor seal, northern elephant seal, California sea lion, Steller sea

lion, and northern and Guadalupe fur seals). The southern sea otter is the only fissiped

known to occur in the waters of southern California.

In the Alaska OCS, oil and gas production activities in Federal waters have

historically been restricted to two separate regions – Cook Inlet and nearshore waters of

the Beaufort Sea. Platform removal is only expected to occur in the Cook Inlet (i.e., only

gravel islands are used for offshore oil and gas production on the Beaufort Sea shelf).

Marine mammals documented during recent surveys in Cook Inlet include beluga whales,

harbor seals, Steller sea lions, and the sea otter, while humpback and fin whales were also

reported along the southern limits of the inlet. Other cetaceans that can occur in the area

but were not observed during recent surveys include killer whale, harbor porpoise, Dall’s

porpoise, Pacific white-sided dolphin, gray whale, minke whale, Baird’s beaked whale,

and Cuvier’s beaked whale. In addition, sperm, Sei, right, and blue whales may wander

into the area. Three other pinniped species – northern fur seal, northern elephant seal,

and Pacific walrus – also may occur in Cook Inlet.

ES-5 Discussion and Recommendations

Major chapters of the synthesis report have reviewed the different technologies

used for explosive structure removals, the physics of underwater detonations, and

potential impacts on marine fishes, marine turtles, and marine mammals. The discussion

chapter discusses the findings, identifies data gaps, and recommends topics where further

study would be appropriate.

This report has focused on three faunal groups: marine fishes, marine turtles, and

marine mammals. Marine turtles and marine mammals are federally protected species for

which death or injury of individual animals is a serious concern. In contrast, although

many fish species associated with offshore platforms are federally managed, impacts on

stocks or populations are the main concern, rather than death or injury of individuals.

While mitigation and monitoring requirements have been established for marine

mammals and turtles, there are no measures specifically developed to protect marine

fishes; rather, it is assumed that fish kills are unavoidable during explosive structure

removals.

Environmental data concerning platform removals serve two main purposes: 1) to

allow impacts to be estimated (e.g., numbers of animals that may be killed or injured

during structure removals); and 2) to aid in developing or refining mitigation measures

that prevent or reduce the likelihood of impacts. Sources of data have included

laboratory and field experiments, modeling studies, and anecdotal field observations.

There are important differences among the three faunal groups discussed in this report

with respect to the types and adequacy of data available (Table ES.1). In general, marine

fishes are the best-studied group, and sea turtles the least studied.
8

Table ES.1

Types and Amounts of Data Available Regarding Impacts of

Underwater Detonations on Marine Fishes, Marine Turtles, and Marine Mammals

Types of Data Available Group Experimental Studies Modeling Anecdotal Observations

Marine

Fishes

Numerous lab and field studies

of explosive effects.

Quantitative studies following

actual structure removals.

Extensive. Many observations (e.g.,

fish kills).

Marine

Turtles

One study with caged turtles

during platform removal (but

no pressure measurements).

Very limited. Mortalities, injuries,

strandings following

detonations.

Marine

Mammals

Recent studies of explosive

effects on dolphin carcasses.

A few auditory effects studies

but most not for explosives.

Several studies on behavioral

effects of seismic sources but

limited relevance.

Limited efforts,

mostly connected

with ship shock trials;

some models used

data from terrestrial

mammals.

Mortalities, injuries,

strandings following

detonations.

Marine Fishes

Lethal effects of underwater explosions on numerous species of fishes have been

studied in laboratory and field experiments and have been modeled extensively. These

data and models have been used to calculate effect ranges. In addition, there have been

studies specifically designed to estimate fish kills associated with structure removals in

the Gulf of Mexico.

One set of calculations reviewed predicts effect ranges varying from 12 m for

non-swimbladder species to 230 to 349 m for swimbladder species. Actual observations

following structure removal detonations indicate most dead fishes were within 25 m, with

numbers declining with distance out to 100 m. Other surveys have shown that fish

densities around platforms are highest within a horizontal distance of 18 to 50 m from the

structure. Therefore, it seems that most fishes associated with platforms are close enough

to be killed or injured by a typical underwater detonation associated with structure

removals. Of course, there are many variables affecting the fate of individual fishes

including their size, shape, vertical position in the water column, and orientation relative

to the detonation source.

The main goal with respect to fish populations is predicting impacts rather than

setting “safety ranges” for mitigation/monitoring. For predicting impacts, the empirical

data from observations during actual structure removals would seem to be more useful

than any attempt to calculate impacts based on experiments and models. Huge variations
9

in the fish population itself, including numbers, species, sizes, and orientation and range

from the detonation, would make it very difficult to accurately predict mortalities at any

specific site. Since the data collected by several researchers are limited in terms of depth

range and geographic extent, additional studies may be needed to predict impacts in other

areas, including deepwater environments.

Marine Turtles

There have been no laboratory studies of explosive impacts on marine turtles, and

only limited field observations and experiments. In several instances, turtle injuries and

mortalities (and in some cases, strandings) have been noted following underwater

detonations. In one case where turtles were recovered after an open-water detonation,

both charge weight and the approximate distances of the turtles from the detonation were

known. Only one field experiment has been conducted in which marine turtles were

exposed at known distances from a structure removal detonation; however, that study did

not include concurrent pressure measurements to estimate the magnitude and duration of

the shockwave received by the caged turtles. There have been several anecdotal reports

of turtle deaths or strandings following structure removal detonations, including a few in

the 15 years since the current mitigation/monitoring requirements were instituted.

There have been no mechanistic models developed specifically to estimate

impacts on marine turtles. Rather, it has been assumed that models developed for other

vertebrates are reasonable approximations. Several researchers developed an equation

for a turtle “safety range” based on field observations of three turtles following an

open-water detonation. The equation is simply based on cube-root scaling of the charge

weight and the distance at which one turtle apparently was not affected. More recently,

another researcher has provided a more conservative version of the same equation but

states that it is based on the criteria for platform removal established by the National

Marine Fisheries Service (NMFS) – i.e., it was not independently derived from

observations or experimental data. Recent environmental assessments have also included

modeling to establish effect ranges using earlier turtle death/injury observations and a

lung injury model. The results suggest that lung injury predictions for marine turtles are

not inconsistent with predictions for small mammals.

An important goal with respect to marine turtles is calculating the areal extent of

the mortality/injury zone so that this area can be monitored for turtles prior to

detonations. In the 1988 “generic consultation” for structure removals in the Gulf of

Mexico, the NMFS specified that the area within 3,000 ft (914 m) of the platform must be

clear of visible marine turtles prior to detonation. The NMFS document does not specify

the source of this number, but apparently it is based on the turtle death/injury

observations to date rather than any modeling.

Years of experience using the 3,000-ft (914-m) range monitored under the

“generic consultation” suggest it has been effective in preventing most deaths or serious

injuries of marine turtles. In addition, the modeling analysis done during recent ship

shock environmental assessments, while not directly addressing the “safety range” for
10

structure removals, suggests that the monitoring range specified in the “generic

consultation” is likely to prevent death and lung injury to marine turtles. However, the

empirical and theoretical basis for this specific number is weak. Although additional

experiments with turtles and underwater explosives are unlikely, some knowledge gained

from marine mammal studies in recent years may be applicable. It is recommended that

existing data be reviewed and modeling conducted to calculate mortality/injury ranges for

marine turtles using standard sound level metrics and incorporating detonation

characteristics appropriate for offshore structure removals. This would provide a firmer

foundation for a turtle “safety range.”

Marine Mammals

Only recently have experimental studies of explosive impacts on marine

mammals been conducted, using animal carcasses. For many years, the only data

available for predicting blast impacts on marine mammals were extrapolations from

experiments on terrestrial mammals submerged in ponds and opportunistic post-mortem

examinations of stranded animals following detonations.

There have been numerous attempts to model explosive impacts on marine

mammals. Most of the research has focused on larger explosions associated with military

testing such as ship shock trials. There also has been considerable research into sublethal

auditory effects such as TTS and permanent threshold shift (PTS), as well as behavioral

responses to underwater noise. Much of the behavioral research has focused on seismic

surveys using airguns rather than explosives. Both blast injury and auditory effects are

topics of ongoing investigations. Since existing marine mammal injury models are based

on old and very limited data, it is likely that these models will be refined or new ones

developed as more information becomes available.

For marine mammals as well as marine turtles, an important goal is calculating

the likely extent of mortality and injury zones so that this area can be monitored for the

presence of animals prior to detonations. Both the 1995 and 2002 regulations issued by

the NMFS for incidental take of bottlenose and spotted dolphins in the Gulf of Mexico

specified a “safety range” of 3,000 ft (914 m). This range for marine mammals is not

based on any independent observations or modeling, but is simply the same range used

for marine turtles under the “generic consultation” under Section 7 of the ESA.

Generic consultation experience (using the 3,000-ft [914-m] monitoring range)

suggests that it has been effective in preventing most deaths or serious injuries of marine

mammals. However, as noted previously for marine turtles, the basis for this specific

number is weak, as it was not developed specifically for marine mammals. As additional

data for blast injury in marine mammals become available and new or refined models are

developed, it is recommended that mortality/injury zones be calculated for marine

mammals using standard sound level metrics and incorporating detonation characteristics

appropriate for offshore structure removals. This would provide a firmer foundation for a

marine mammal “safety range.”
11

Auditory effects such as TTS and PTS may occur beyond the “safety range”

monitored during structure removals. These effects are of particular concern for marine

mammals because of the regulatory implications of the MMPA, which prohibits

“harassment.” In various regulations for ship shock trial and seismic surveys,

NOAA-Fisheries ([NOAA-F]; previously NMFS) has accepted TTS as a criterion for

marine mammal harassment. This is an area of ongoing research in which criteria are

being developed and refined. The MMS should coordinate with NOAA-F to make use of

the most recent findings and criteria in evaluating auditory impacts on marine mammals.

Physics of Underwater Detonations

The understanding of the physical principles of underwater detonations and of the

propagation of shock and sonic waves in the surrounding medium is in itself quite well

developed. There are, however, significant gaps in the application of this knowledge to

actual removal of offshore structures. The containment effect provided by setting the

structure-cutting charges below a minimum prescribed depth of sediment has not been

documented for a comprehensive range of seafloor consistencies, with the result that the

extent of the transmission of explosive energy into the water column may be significantly

greater than expected. Much of what is known from experience regarding underwater

detonations within the seafloor comes from rock demolition blasting, which by its very

nature is performed in an altogether different medium from the relatively compliant upper

layers of sediment in which structure-cutting charges are deployed.

A systematic research effort should be undertaken to model numerically the blast

propagation for a range of charge sizes consistent with structure removal practices

through a wide variety of sediment types and for different deployment depths below the

sediment surface. Such modeling should extend to the transfer of energy into the water

column both from the shock wave propagating through the interface and later decaying

into an acoustic signal, and from the oscillating bubble of detonation gases when

breakout into the water does take place. Experimental validation of model results at

every possible opportunity should form an integral part of the study; this requires

accurate measurement of acoustic levels, and preferably full waveform recording, at one

or more locations in the water columns as well as characterization of the sediment

firmness near the structures being removed, which could be done by penetrometer

probing or similar techniques.

Once a reliable modeling approach has been generated and validated, forecasting

of the acoustic levels distribution for planned operations would become possible from the

type and location of the charge to be exploded, the depth of the water column, and the

measured properties of the sediment in which the detonation occurs. In combination with

improved estimation of impact thresholds based on appropriate and standardized sound

metrics for marine mammals and turtles, such a modeling-based assessment of each

planned decommissioning operation involving explosive removal of underwater

structures would provide the best ability to minimize its repercussions on marine life.
12

ES-6 Conclusions

A series of conclusions were reached following compilation, review, analysis, and

summarization of data sources pertinent to the use of underwater explosives in platform

removal, the presence of sensitive marine resources and impacts associated with

underwater explosives use as applied to platform removal. Recognized data gaps and

recommendations for future research also were identified.

The most commonly used technique for explosive cutting of piles and conductors

is with bulk explosive charges. Other techniques such as ring charges, focusing charges,

linear shaped charges, and cutting tape are used in some instances. Increased use of

techniques that involve smaller charge sizes could reduce potential impacts on marine

life.

The physical principles of underwater detonations and of the propagation of shock

and sonic waves in the surrounding medium are well understood, but there are significant

gaps in applying this knowledge to actual removal of offshore structures. It is

recommended that a research effort be undertaken to model numerically blast

propagation for a range of charge sizes consistent with structure removal practices

through a variety of sediment types and for different deployment depths below the

sediment surface. Experimental validation of model results should form an integral part

of the study. Ultimately, forecasting of the acoustic levels distribution for planned

operations would become possible from the type and location of the charge to be

exploded, the depth of the water column, and the measured properties of the sediment in

which the detonation occurs.

Environmental data concerning platform removals serve two main purposes: 1) to

allow impacts to be estimated (e.g., numbers of animals that may be killed or injured

during structure removals); and 2) to aid in developing or refining mitigation measures

that prevent or reduce the likelihood of impacts. Impact estimation is the main goal with

respect to marine fishes, whereas for marine turtles and marine mammals, mitigation is

the main goal (i.e., predicting the areal extent of mortality and injury zones so that these

can be monitored prior to detonation to prevent impacts).

There are important differences among marine fishes, marine turtles, and marine

mammals with respect to the types and adequacy of data available. In general, marine

fishes are the best-studied group, and marine turtles the least studied. Effects of

underwater explosions on fishes have been studied and modeled extensively, and field

studies have quantified fish kills associated with structure removals in the Gulf of

Mexico. For marine turtles, there have been no laboratory studies of blast injury, only

limited field observations and experiments, and no mechanistic models developed

specifically to estimate impacts. For many years, the main data available for predicting

both blast and auditory impacts on marine mammals were extrapolations from terrestrial

mammal studies, but ongoing studies are underway that will aid in developing improved

mortality, injury, and auditory impact criteria.
13

For predicting impacts on marine fishes, the empirical data from observations

during actual structure removals would seem to be more useful than any attempt to

calculate impacts based on experiments or mechanistic models. Since existing

observations cover a limited geographic and water depth range, additional observations

will be needed to better estimate future impacts.

Years of experience using the 3,000-ft (914-m) “safety range” monitored under

the “generic consultation” suggest it has been effective in preventing most deaths and

serious injuries of marine turtles and marine mammals. However, the empirical and

theoretical basis for this specific number is weak. It is recommended that

mortality/injury zones be calculated for marine turtles and marine mammals using

standard sound level metrics and incorporating detonation characteristics appropriate for

offshore structure removals. This would provide a firmer foundation for marine turtle

and marine mammal “safety ranges.”

In all three groups, there is relatively little information about sublethal impacts,

particularly on the auditory system. While mitigation measures appear to be effective in

preventing death or injury of mammals and turtles, it is uncertain to what extent sublethal

effects may be occurring beyond the safety range. Recent and ongoing studies may

provide the basis for estimating auditory impacts in marine mammals, which are

particularly important in the regulatory context of “harassment” under the MMPA. There

is almost no information to estimate auditory impacts on marine turtles.

The time interval between shots may be an important mitigation measure. The

amount of time for an animal to recover from a shock wave is unknown. Do closely

spaced shock waves, each of which is insufficient to cause damage, cause damage in a

proportion to the sum of the damage parameters or a sum of a time dependent percentage

of damage parameters? The effect of short time intervals between blasts such as those

used in Gulf of Mexico structure removals has not been addressed.

The Office of Naval Research (ONR) is conducting research on physical and

auditory effects of blast parameters on marine mammals and detection of marine

mammals with passive acoustic devices. Synergy between MMS and the ONR in these

areas of research would be fruitful. The Department of the Navy, Naval Surface Warfare

Center is measuring actual blast parameters in the sea and working on new and/or

revisions to blast propagation models. Synergy with this group would also be fruitful.

To date, mitigation and monitoring requirements for structure removals in the

Gulf of Mexico have focused on marine turtles, bottlenose dolphins, and spotted

dolphins. As structures are removed in greater water depths, many more species of

marine mammals are likely to be encountered, including one endangered species (sperm

whale) and other deep-diving species (such as beaked whales) that pose challenges for

detection. Passive acoustic monitoring could aid in the detection of sperm whales. Not

enough is known about the vocal behavior of beaked whales and some other species to

determine the probability of their being detected by passive acoustic monitoring.
15

CHAPTER 2

INTRODUCTION

Nearly 4,000 oil and gas structures currently exist in Federal waters of the U.S.

outer continental shelf (OCS), with the vast majority present in the Gulf of Mexico. The

primary purpose of these structures (e.g., fixed platforms) is to develop and produce oil,

natural gas, and gas condensates from offshore hydrocarbon reservoirs. Once offshore

production from a producing field becomes uneconomic, the lease(s) may be terminated

by the operator. As one of the conditions allowing the Federal government to lease

offshore blocks to interested oil and gas operators, lease clearance requirements mandate

that operators (responsible for installation and operation of a platform) subsequently

remove the structure within a year of lease termination.

Platform removal typically involves the use of explosives to sever platform legs

several feet below the seafloor. A typical fixed platform and its primary components are

depicted in Figure 2.1. Historically, offshore development and production of oil and gas

reserves has occurred in shelf waters. Consequently, most platform removals conducted

to date have been located in shallower water depths (i.e., <200 m). Movement of

production platforms farther offshore, coupled with recent interest in deepwater

development, however, has raised the issue of future platform removal in deeper OCS

waters (e.g., over the continental slope). Further, the presence of listed (i.e., endangered

or threatened species listed or proposed for listing under the Endangered Species Act

[ESA]) and/or protected species (i.e., marine mammals protected under the Marine

Mammal Protection Act [MMPA]) in marine waters, coupled with the mandate to

minimize or eliminate the potential for impact to these species, underscores the need to

fully understand the environmental impacts associated with explosive platform removal.

To properly assess the impacts associated with explosive platform removal, the

U.S. Department of the Interior, Minerals Management Service (MMS) requires access to

the best available information. Topics of interest in this regard include a thorough

characterization of explosive removal technologies and techniques, and the

environmental impacts resulting from these underwater demolitions. The focus of the

present study was to collect and synthesize existing information relevant to explosive

removal of offshore structures in aquatic environments. While the expected application

of this knowledge may include U.S. waters (e.g., Gulf of Mexico, California, Alaska

OCS), the scope of this effort is worldwide. Sensitive marine resources considered in this

analysis include marine fishes, marine turtles, and marine mammals.

2.1 MMS Mission and Regulations

The MMS is mandated by the OCS Lands Act, as amended, to manage the

development of OCS oil, gas, and mineral resources, while protecting the human, marine,

and coastal environments. While mineral resource exploration and development/

production on the OCS is typically represented by the use of mobile offshore drilling

units or the placement of fixed or floating platforms, the final stages of facility
Figure 2.1. Profile diagram showing the major components of a representative fixed oil and gas

platform.

Mud Line

Water Line

Deck

 Structure

Jacket

Piles
17

decommissioning and lease abandonment frequently entail the removal of a platform that

has been fixed to the seafloor.

Regulations relevant to OCS oil and gas operations are codified in 30 Code of

Federal Regulations (CFR) Part 250. Table 2.1 summarizes those portions of the Federal

regulations that pertain to the decommissioning and removal of OCS oil and gas facilities

through 1995.

The Marine Board of the National Research Council (NRC) (NRC, 1996)

published an analysis of offshore structure removal techniques (“An Assessment of

Techniques for Removing Offshore Structures”) in early 1996. In April 1996, MMS

convened the International Decommissioning Workshop in New Orleans, LA to discuss

the recommendations in the NRC report and current industry decommissioning practices.

On 8 August 1996, MMS published a notice (Federal Register 61:41,422) requesting

comments on plans to further refine previous workshop recommendations. Several other

public workshops also were held by MMS to solicit responses and recommendations

regarding decommissioning operations.

In May 2002, MMS issued a final rule (Federal Register 67(96):35,397-35,412)

amending its regulations governing oil and gas operations on the OCS to update

decommissioning requirements. The rule included requirements for plugging a well,

decommissioning a platform and pipeline, and clearing a lease site. MMS restructured

and updated the requirements to make the regulations more user-friendly and to reflect

changes in technology. Final technical changes implemented in July 2002 further ensure

that lessees and pipeline right-of-way holders conduct their decommissioning operations

safely and effectively. Specifically, 30 CFR 250 Subpart Q was implemented to

1) determine that decommissioning activities comply with regulatory requirements and

approvals and to 2) ensure that site clearance and platform (or pipeline removal) are

properly performed to protect marine life and the environment, and do not conflict with

other users of the OCS. Table 2.2 outlines the May 2002 major elements of the final rule

that are relevant to platform removal, as found in Section 250.1725-250.1730 of the final

rule. Table 2.3 summarizes revised reporting requirements effective July 2002.

MMS also coordinates with the National Oceanic and Atmospheric

Administration, Fisheries Division (NOAA-F; formerly the National Marine Fisheries

Service [NMFS]) in compliance with existing environmental laws – ESA for listed

species (i.e., all marine turtles, select marine mammals) and MMPA (protected marine

mammals).1

 

1 For proposed activities that may affect the endangered West Indian manatee, MMS consults with the U.S.

Fish and Wildlife Service in a similar role. Because manatees are strictly inland waterway/near coastal

water inhabitants of the Gulf, it is extremely unlikely that they will be affected by explosive platform

removals on the OCS.
Table 2.1

Summary of Minerals Management Service (MMS) Regulatory Requirements Relevant to the Decommissioning 

Shelf (OCS) Oil and Gas Facilities, as Codified in 30 CFR Part 250 (Adapted from: MMS and California State 

1997)

Regulation Title andSection Relevant RequirementsPermanent Abandonmentof Wells(250.110, 250.111,250.112, 250.114)

 All well sites shall be cleared in a manner so as to avoid conflict with other uses of the  Lessee shall not initiate abandonment activities without the prior approval of the MMS  Lessee must submit a request to abandon a well on Form MMS-124 (Sundry Notices an

to the MMS District Supervisor for approval; subsequently, a report outlining abandonmbe submitted to the MMS within 30 days of completion of the work.

 Form MMS-124 shall specify the date the work is to be performed, the extent of the are

around the location (e.g., well site), and the search methods used.

 All wellheads, casings, pilings, and other obstructions shall be removed to a depth of at 

mud line, or to a depth approved by the MMS District Supervisor.

 Lessee shall verify that the location has been cleared of all obstructions. The requirements for removing subsea wellheads or obstructions, or for verifying locat

reduced or eliminated if the MMS District Supervisor determines that the wellheads or not constitute a hazard to other uses of the seafloor or other legitimate uses of the area.

 Lessee shall verify site clearance after abandonment by one or more of the following m

by the MMS District Supervisor: 1) drag trawl in two directions across each location; 2search around the wellbore; 3) scan across the location with a side-scan or on-bottom s4) use other methods based on particular site conditions.

 Lessee shall submit certification that the area was cleared of all obstructions, the date th

conducted, the extent of the area searched around the location (e.g., well site), and the sutilized; lessee to use Form MMS-124.
Table 2.1. Summary of Minerals Management Service (MMS) Regulatory Requirements Relevant to the Decom

Continental Shelf (OCS) Oil and Gas Facilities, as Codified in 30 CFR Part 250 (Adapted from: MM

State Lands Commission 1997) (continued).

Regulation Title andSection Relevant RequirementsTemporary Abandonmentof Wells(250.113)

 Subsea wellheads, casing stubs, or other obstructions remaining after temporary abando

seafloor shall be protected in such a manner as to allow commercial fisheries gear to pawithout damage to the structure or the fishing gear.

 Depending upon water depth, the nature and height of the obstruction above the seafloo

periods of fishing activity in the area, the MMS District Supervisor may waive this requ

 Lessee shall follow appropriate U.S. Coast Guard requirements in identifying and repor

casing stubs, and other obstructions extending above the mud line.

Platform Removal andLocation Clearance(250.143)

 Structures are to be removed in a manner approved by the MMS Regional Supervisor t

location has been cleared of all obstructions to other activities in the area.

 All platforms (including casing, wellhead equipment, templates, and pilings) shall be re

least 15 ft below the ocean floor, or to a depth approved by the MMS Regional Supervitype of structure or ocean bottom conditions.

 Lessee shall verify that the location has been cleared of all obstructions. Results of a site-specific clearance survey shall be submitted to the MMS Regional Sup A letter certifying that the area was cleared of all obstructions, the date the work was p

the area surveyed, and the survey methods used shall be submitted to the MMS Region

Abandonment ofPipelines(250.156)

 A pipeline may be abandoned in place, if the MMS Regional Supervisor determines tha

a hazard to navigation, commercial fishing operations, or unduly interfere with other O

 Pipelines abandoned in place shall be flushed, filled with seawater, cut, and plugged; p

buried at least 3 ft.
Table 2.2

Summary of Pertinent Requirements for Platform and Other Facility Removal from the Outer Continental Shelf 

Regulations (Adapted from: Federal Register 67(96):35,397-35,412)

30 CFR

Section Title and Summary of Requirement(s)

250.1725 When do I have to remove platforms and other facilities?

An operator:(a) Must remove all platforms and other facilities within 1 year after the lease or pipeline right-of-way ter

receiving approval to maintain the structure to conduct other activities. Platforms include production pconductors, single-well caissons, and pipeline accessory platforms.

(b) Before removing a platform or other facility, must submit a final removal application to the Regional S

and include the information listed in Sec. 250.1727.

(c) Must remove a platform or other facility according to the approved application.

(d) Must flush all production risers with seawater before removal,(e) Must notify the Regional Supervisor at least 48 hours before beginning the removal operations.

250.1726 When must I submit an initial platform removal application, and what must it include?

An initial platform removal application is required only for leases in the Pacific OCS Region or the Alaska 

include the following information:(a) Platform or other facility removal procedures, including the types of vessels and equipment to be used(b) Facilities (including pipelines) to be removed or left in place;(c) Platform or other facility transportation and disposal plans;

(d) Plans to protect marine life and the environment during decommissioning operations, including a brief 

environmental impacts of the operations, and procedures and mitigation measures to be taken take to mand

(e) A projected decommissioning schedule.

250.1727 What information must I include in my final application to remove a platform or other facility?

Operators must submit a final application to remove a platform or other facility to the Regional Supervisor requirement applies to leases in all MMS Regions. If proposing use of explosives, operators are to provide application. If no explosives are proposed, only two copies of the application are to be provided. The foll

be included in the final removal application, as applicable:
Table 2.2. Summary of Pertinent Requirements for Platform and Other Facility Removal from the Outer Contine

Updated Regulations (Adapted from: Federal Register 67(96):35,397-35,412) (continued).

30 CFR

Section Title and Summary of Requirement(s)

(a) Identification of the applicant including:

(1) Lease operator/pipeline right-of-way holder;(2) Address;(3) Contact person and telephone number; and(4) Shore base.

(b) Identification of the structure being removed including:

(1) Platform Name/MMS Complex ID Number;(2) Location (lease/right-of-way, area, block, and block coordinates);(3) Date installed (year);(4) Proposed date of removal (month/year); and(5) Water depth.

(c) Description of the structure being removed including:

(1) Configuration (attach a photograph or a diagram);(2) Size;(3) Number of legs/casings/pilings;(4) Diameter and wall thickness of legs/casings/pilings;(5) Whether piles are grouted inside or outside;(6) Brief description of soil composition and condition;(7) The sizes and weights of the conductor, topsides (by module), conductors, and pilings; and(8) The maximum removal lift weight and estimated number of main lifts to remove the structure.

(d) A description, including anchor pattern, of the vessel(s) to be used to remove the structure.(e) Identification of the purpose, including:

(1) Lease expiration/right-of-way relinquishment date; and(2) Reason for removing the structure.

(f) A description of the removal method, including:

(1) A brief description of the method to be used;(2) If explosives are to be used, the following:

(i) Type of explosives;(ii) Number and sizes of charges;
Table 2.2. Summary of Pertinent Requirements for Platform and Other Facility Removal from the Outer Contine

Updated Regulations (Adapted from: Federal Register 67(96):35,397-35,412) (continued).

30 CFR

Section Title and Summary of Requirement(s)

(iii) Whether single shot or multiple shots are to be employed;(iv) If multiple shots, the sequence and timing of detonations;(v) Whether bulk or shaped charges are to be used;(vi) Depth of detonation below the mud line; and(vii) Whether explosives are being placed inside or outside of the pilings;

(3) If divers or acoustic devices are to be used to conduct a pre-removal survey to detect the presence o

mammals, a description of the proposed detection method; and

(4) A statement whether or not the operator will use transducers to measure the pressure and impulse o

(g) Operator plans for transportation and disposal (including as an artificial reef) or salvage of the remove(h) If available, the results of any recent biological surveys conducted in the vicinity of the structure and r

turtles or marine mammals at the structure site.

(i) Operator plans to protect archaeological and sensitive biological features during removal operations, in

assessment of the environmental impacts of the removal operations and procedures and mitigation meaminimize such impacts.

(j) A statement whether or not the operator will use divers to survey the area after removal to determine a

life.

250.1728 To what depth must I remove a platform or other facility?

(a) Unless the Regional Supervisor approves an alternate depth under paragraph (b) of this section, operato

platforms and other facilities (including templates and pilings) to at least 15 ft below the mud line.

(b) The Regional Supervisor may approve an alternate removal depth if:

(1) The remaining structure would not become an obstruction to other users of the seafloor or area, and 

information you provide demonstrates that erosional processes capable of exposing the obstruction

(2) The operator determines, and MMS concurs, that divers must be used and the seafloor sediment sta

concerns; or

(3) The water depth is greater than 800 m (2,624 ft).
Table 2.2. Summary of Pertinent Requirements for Platform and Other Facility Removal from the Outer Contine

Updated Regulations (Adapted from: Federal Register 67(96):35,397-35,412) (continued).

30 CFR

Section Title and Summary of Requirement(s)

250.1729 After I remove a platform or other facility, what information must I submit?

Within 30 days after an operator removes a platform or other facility, the operator must submit a written re

Supervisor that includes the following:(a) A summary of the removal operation including the date it was completed;

(b) A description of any mitigation measures taken; and(c) A statement signed by the operator’s authorized representative that certifies that the types and amount 

removing the platform or other facility were consistent with those set forth in the approved removal ap

250.1730 When might MMS approve partial structure removal or toppling in place?

The Regional Supervisor may grant a departure from the requirement to remove a platform or other facility structure removal or toppling in place for conversion to an artificial reef or other use if the following cond(a) The structure becomes part of a State artificial reef program, and the responsible State agency acquires 

Army Corps of Engineers and accepts title and liability for the structure; and

(b) The operator satisfies any U.S. Coast Guard (USCG) navigational requirements for the structure.
24

Table 2.3

Summary of Reporting Requirements, Per Updated Decommissioning Regulations

(From: Federal Register 67(96):35,397-35,412)

Citation

(30 CFR 250 subpart Q) Reporting Requirement

1703; 1704.... Request approval for decommissioning.

1704(f); 1712; 1716;

1717;

1721(a), (f), (g);

1722(a),(b), (d); 1723(b);

1743(a)

Submit form MMS-124 to plug wells; provide subsequent report;

request alternate depth departure; request procedure to protect

obstructions above seafloor; report results of trawling; certify area

cleared of obstructions; remove casing stub or mud line suspension

equipment and subsea protective covering; or other departures.

1713 (Final New)........... Notify MMS 48 hours before beginning operations to permanently

plug a well.

1721(e); 1722(e), (h)(1);

1741(c).

Identify and report subsea wellheads, casing stubs, or other

obstructions; mark wells protected by a dome; mark location to be

cleared as navigation hazard.

1722(c), (g)(2) (Final

New)...

Notify MMS within 5 days if trawl does not pass over protective

device or causes damages to it; or if inspection reveals casing stub or

mud line suspension is no longer protected.

1722(f), (g)(3)............... Submit annual report (75 copies) on plans for re-entry to complete or

permanently abandon the well and inspection report.

1722(h) (Final

New)...........

Request waiver of trawling test.

1704(a); 1726 (Proposed

New)...

Submit initial decommissioning application in Pacific OCS and

Alaska OCS Regions.

1704(b); 1725; 1727;

1728;

1730.

Submit final application to remove platform or other subsea facility

structures (including alternate depth departure) or approval to

maintain, to conduct other operations, or to convert to artificial reef.

1725(e) (Final New)......... Notify MMS 48 hours before beginning removal of platform and

other facilities.

1704(c); 1729 (Final

New)........

Submit post platform or other facility removal report.

1740(b)(5), (c)(3);

1740(g)(1); 1743(b)

Request approval of well site, platform, or other facility clearance

method; including contacting pipeline owner or operator.

1743(b)....................... Verify permanently plugged well, platform, or other facility removal

site cleared of obstructions and submit certification letter.

1704(d); 1751;

1752...........

Submit application to decommission pipeline in place or remove

pipeline.

1753 (Final New)............. Submit post-pipeline decommissioning report.

1700 through 1754........... General departure and alternative compliance requests not

specifically covered elsewhere in subpart Q regulations.
25

2.1.1 ESA Consultation and Related Requirements

MMS complies with the Section 7 provisions of the ESA through consultation to

minimize potential impacts to listed species. All sea turtle species occurring in offshore

waters of the Gulf of Mexico are protected under the ESA.

In 1988, the NMFS issued a “generic consultation” covering structure removal

activities on the Gulf of Mexico continental shelf (NMFS 1988), following completion of

an MMS programmatic environmental assessment that evaluated structure removal

activities (MMS 1987). The generic consultation specified mitigation and monitoring

requirements to prevent death or injury of sea turtles.

In order for a platform removal proposal using explosive technology to be

considered under the generic consultation, it must conform to the following

specifications:

1) Each explosive charge must be 50 lb or less;

2) Detonations must be limited to groups of eight or less with a minimum of

0.9 sec between detonations;

3) High velocity explosives must be used with a detonation rate of 7,600 m/sec

or greater; and

4) Charges must be placed a minimum of 5 m (15 ft) below the mud line.

The NOAA-F requires the following mitigation measures under the generic consultation:

1) Qualified observers must monitor the area around the site prior to, during, and

after detonation of charges. This observer coverage must begin 48 hours prior

to the detonation of charges, and if sea turtles are thought to be resident in the

area, pre- and post-detonation diver surveys must be performed;

2) A 30-minute aerial survey must be performed within 1 hour before and 1 hour

after each blasting sequence;

3) If sea turtles or marine mammals are observed within 914 m (1,000 yd) of the

structure, detonation will be delayed until such creatures are beyond the 914 m

(1,000 yd) range, and the aerial survey repeated;

4) Detonation of explosives will occur no sooner than 1 hour after sunrise and no

later than 1 hour prior to sunset;

5) During all diving operations, divers must look for sea turtles and marine

mammals. All sightings must be reported; and

6) Use of “scare charges” or explosive devices to frighten marine mammals out

of the blasting area is discouraged, and may be used only after obtaining

special permission.

Several listed marine mammal species may occur in the Gulf of Mexico (see

Section 5.3), the most common of which is the endangered sperm whale, a species that

prefers the deeper waters (>200 m) of the Gulf. All endangered or threatened marine

mammals are unlikely to be affected by platform removals on the Gulf of Mexico
26

continental shelf because no listed species are commonly found there. Therefore, no

marine mammals are included in the ESA “generic consultation” (NMFS 1988). Future

structure removals in deepwater, however, may affect the endangered sperm whale and

would require additional consultation between MMS and NOAA-F under Section 7 of the

ESA. The MMS is preparing a biological assessment for the ESA consultation to address

the explosive removal of oil and gas structures at all water depths. The threatened and

endangered species expected to be addressed during the ESA consultation will be sea

turtles and the sperm whale.

MMS has also implemented region-specific restrictions on explosive platform

removal activities. For example, the Gulf of Mexico OCS Region has implemented

Notice to Lessees and Operators (NTL) No. 2001-G08. This NTL places restrictions on

explosive platform removals, requiring operators to monitor for the presence of sea

turtles or marine mammals and to conduct explosive operations in a manner that will

minimize the likelihood of harm to these individuals. Further, NTL 2001-G08 also

requires that the MMS must initiate a new ESA Section 7 consultation with the NMFS

for the following types of explosive structure removal method applications:

1) An application proposing an explosive structure removal operation that does

not comply with the criteria and terms and conditions of the ESA Section 7

“generic consultation” noted above; and

2) An application proposing an explosive removal operation in water depths

200 m (656 ft) or greater. The Gulf of Mexico OCS Region has determined

that explosive removals in these areas “may affect” sperm whales, an

endangered species.

2.1.2 MMPA Concerns

Killing or injuring any marine mammal is considered to be “take” and is

prohibited under the MMPA. The unintentional taking of a protected marine mammal,

termed incidental take, may be approved by NOAA-F if such take is determined to

produce only a negligible impact to a species stock or habitat. In practice,

MMPA-related efforts have focused on bottlenose dolphins and spotted dolphins, which

are by far the most common marine mammals on the Gulf of Mexico continental shelf.

In 1995, NMFS established appropriate structure removal criteria (i.e., maximum

charge size, monitoring and reporting requirements) for waters of the Gulf of Mexico

(Federal Register 60(197):53,139-53,147). These criteria took into account the potential

for the incidental take of several protected marine mammal species, specifically outlining

regulations authorizing and governing the taking of bottlenose and spotted dolphins

incidental to the removal of oil and gas drilling and production structures in state and

OCS waters of the Gulf. The incidental taking of small numbers of marine mammals

may be authorized under the MMPA if certain findings are made and regulations are

issued that include requirements for monitoring and reporting. As noted by NMFS, these

regulations authorized the unintentional incidental take of marine mammals in connection

with such activities over a 5-year period (1995-2000) and prescribed methods of taking
27

and other means of effecting the least practicable adverse impact on the species and its

habitat. On 13 November 2000, these regulations expired and NMFS could no longer

issue authorization (i.e., Letters of Authorization [LOAs]) for structure removal activities

in the Gulf of Mexico.

At the request of the oil and gas industry, NMFS established new criteria in 2002

relevant to structure removal in the Gulf of Mexico. The 2002 criteria were established

as an interim policy statement (Federal Register 67(148):49,869-49,875) to provide the

industry with protection from incidental take liability under the MMPA, given that the

1995 requirements had expired. The current criteria are effective only for the period

1 August 2002 through 2 February 2004.

The incidental take regulations issued by NMFS in 1995 and 2002 cover only

bottlenose and spotted dolphins. These regulations, which include mitigation and

monitoring requirements, will expire in February 2004. The MMS has committed to

petition NOAA-F for new regulations and incidental take authorization as part of their

approval process to allow future removal of offshore structures in the Gulf of Mexico.

For all dismantling operations requiring the use of explosives that do not meet the

existing requirements, NOAA-F requires that applications for approval must be initiated

on a case-by-case basis.

2.2 Study Purpose and Objectives

The purpose of the investigation was to collect and synthesize information on

explosive removals of offshore structures in aquatic environments. This information is

needed by MMS to assist in their review, monitoring, and evaluation of impacts

associated with explosive platform removal.

The primary study objectives were to:

1) provide a summary of available information by topic;

2) identify information and data gaps that could be filled by subsequent research

activities; and

3) recommend areas of research to meet MMS information needs.

Deliverables prepared under this contract include a unified electronic

bibliography (a hard copy version is included with this report as the Appendix), a list of

data and other sources, and this synthesis report summarizing the scope, coverage, and

quality of the materials found.

2.3 Project Team

To address the study objectives, specialized technical expertise was incorporated

into the project team, with several key individuals designated as Principal Investigators

(PIs). A listing of key project personnel and their respective area(s) of expertise and

affiliations follows:
28

 Continental Shelf Associates, Inc. (CSA) (Jupiter, FL) – prime contractor

 Stephen T. Viada – Program Manager; PI, Marine Turtles

 David B. Snyder – PI, Marine Fishes

 M. John Thompson – PI, Platform Removal Techniques

 Neal W. Phillips – Environmental Impacts of Explosives

 Brian J. Balcom – Editor

 LGL Ltd. (King City, Ontario, Canada) – subcontractor

 Denis Thomson – PI, Marine Mammals

 W. John Richardson – Marine Mammals

 JASCO Research Ltd. (Victoria, British Columbia, Canada) – subcontractor

 Roberto Racca – PI, Underwater Explosives and Platform Removal

 David Hannay – Underwater Explosives and Platform Removal

Technical review regarding underwater explosives was also provided by William

Poe of Explosive Service International, Ltd., Baton Rouge, LA. A Quality Review Board

(QRB) also was formed to provide expert review and comment on the draft version of the

information synthesis report. The QRB consisted of Charles Greene (Greeneridge

Sciences, Santa Barbara, CA) and Greg Gitschlag (NMFS, Galveston, TX).

2.4 Study Methods and Report Organization

The study effort was divided into two separate tasks, as detailed below.

Recognizing that the primary purpose of the study effort was to identify and review

salient data sources for each topic area, pertinent references were used to 1) develop the

Information Synthesis Report and 2) create a separate electronic database.

2.4.1 Task 1 – Information Search/Collection and Data Management

The PIs were used as resources to identify and judge the completeness of the

database in each subject area. The goal of the information collection plan was to supply

published and unpublished literature to each PI according to their individual needs and to

compile a computerized bibliographic database. Information gathered included pertinent

data sources in the following topics:

 Explosive Removal Methods;

 Physics of Underwater Explosions;

 Biological Resources;

 Impacts to Biological Resources; and

 Mitigation and Monitoring of Effects

For each reference incorporated into the bibliographic database, the following

information was provided:
29

 Author;

 Date;

 Article or Chapter Title;

 Journal/book/volume information or location, if unpublished;

 Pages;

 Publisher;

 Geographic location covered, such as ecosystem, habitat, latitude/longitude;

 Key words and discipline; and

 Format/media (e.g., paper, magnetic disks or tapes), if data.

Unpublished data and ongoing research studies have been included as references

in the database. The format for these references within the database includes the

following:

 Data type;

 Data source and/or location;

 Collection location;

 Sampling period;

 Sampling frequency;

 Number of stations;

 Data availability (proprietary or non-proprietary);

 Key words;

 Accession number;

 Collector or research/institution; and

 Format/media (e.g., paper, magnetic disks or tapes), if data.

The information collection process represented a compilation of existing data

from the CSA in-house database and library, from personal libraries of each PI, and from

computer searches of online databases. The following journals were reviewed and

organizations contacted:

 Acoustical Society of America;

 Journal of Geophysical Research;

 Geophysics;

 Journal of Computational Acoustics;

 NMFS; and

 Canadian Acoustical Association.

All data sources were organized within a preliminary electronic bibliographic database.

A large fraction of the literature dealing with sound and blast energy from

underwater explosive detonations is not available in open publication. One of the

project’s subcontractors (JASCO) has participated in numerous studies that have resulted

in reports and publications that would normally be difficult to obtain. JASCO maintains

a large internal library of publications related to underwater blasts and underwater
30

acoustics in general, including reports produced for or by the following members of

government agencies, academia, and the private sector:

 U.S. Army Corps of Engineers;

 National Defence Headquarters Canada;

 Defence Research Establishment Pacific Canada;

 Defence Research Establishment Atlantic Canada;

 Naval Surface Warfare Center (San Diego, CA);

 Institute of Ocean Science (British Columbia, Canada); and

 Private petroleum companies.

JASCO also requested literature from a series of associates in government

laboratories and universities with expertise in the fields of underwater acoustics, marine

geophysics, and blast physics.

LGL Ltd. has an extensive library with relevance to impacts of underwater

explosions on marine life. Most of the material is in the form of reports and gray

literature, with only limited amounts of material in the published literature. Sources

included the following:

 Reports produced by the Naval Surface Weapons Center, Dahlgren, Silver

Spring, Cardrock, and Indian Head and the Lovelace Foundation

(Albuquerque, NM). These include the results of experiments on terrestrial

mammals and modeling done for various ship shock trials and other

underwater explosions done by the U.S. Navy;

 Reports and guidelines for the use of explosives, including jetted charges by

Fisheries and Oceans Canada;

 Regulations pertaining to underwater explosions published in the CFR; and

 Reports produced by the U.S. Army Corps of Engineers.

Online databases were searched using the DIALOG Information Retrieval

Service. These database searches, conducted by Harbor Branch Oceanographic

Institution, were completed for each specific topic area – explosive removal methods,

physics of underwater explosions, biological resources, and impacts to biological

resources. Databases searched included the following:

 Aquatic Science and Fisheries Abstracts;

 BIOSIS Previews (Biological Abstracts);

 CA Search (Chemical Abstracts);

 CENDATA;

 Conference Papers Index;

 Dissertation Abstracts;

 Energy Science and Technology;

 GEOREF (American Geological Institute);

 Life Sciences Collection;

 Meteorological and Geoastrophysical Abstracts;
31

 National Technical Information Service (NTIS);

 Oceanic Abstracts;

 Scisearch Database (Science Citation Index); and

 Zoological Record.

These data were incorporated into the preliminary bibliography database in an

electronic and searchable format.2

 The preliminary bibliography was reviewed for

completeness by the PIs. Additional citations and abstracts were identified and

incorporated into the bibliography. In addition, supplemental information sources were

identified through contacts with various agencies, organizations, and individuals. This

revised bibliographic database was used in completion of the second task – the

preparation of the Information Synthesis Report.

2.4.2 Task 2 - Information Synthesis Report

This Information Synthesis Report comprises nine separate and inter-related

chapters. Chapter 1 (Executive Summary) provides an overview of the synthesis report –

major findings, identified data gaps, and recommendations for future research – dealing

with the explosive removal of offshore platforms and their effects on sensitive resources.

Chapter 2 (Introduction) outlines the major objectives of the study effort, identifies the

project team, outlines MMS mandate and regulatory requirements associated with OCS

structure removal, summarizes the tasks completed, and outlines the organization of the

synthesis report. Chapter 3 (Decommissioning and Explosive Removal Methods)

provides a description of explosive structure removal methods, including methods that

are presently in service and methods currently under design. Chapter 4 (Physics of

Underwater Explosions) provides a detailed and technical description of the physics of

underwater explosions, including shock wave and acoustic properties of explosive

removals, and parameters that affect shock wave propagation and intensity. Chapter 5

(Affected Environment) provides individual summaries of marine fishes, marine turtles,

and marine mammals, describing an overview of these biological resources. Chapter 6

(Environmental Consequences) provides a synthesis of environmental effects to each of

the sensitive resources from explosive structure removals, based upon available literature

and data. Chapter 7 (Mitigation and Monitoring) discusses mitigation and monitoring

methods presently in use and proposed methods. Chapter 8 (Discussion and

Recommendations) outlines a proposed impact matrix (i.e., threshold distances from an

explosive source that, based on an analysis of available data, correspond to lethal,

sublethal physiological, and sublethal behavioral impacts to marine fishes, marine turtles,

and marine mammals), identifies alternative actions, summarizes identified data gaps,

and provides summary recommendations for future research to address MMS needs.

Chapter 9 provides a conclusion to the synthesis report.

 

2 i.e., ProCite. ProCite incorporates results from tagged DIALOG searches directly into a bibliographic

database. For the final report, the ProCite bibliographic database was exported into Microsoft Access

2000. The Microsoft Access 2000 database is provided as the Appendix to this report.
33

CHAPTER 3

DECOMMISSIONING AND EXPLOSIVE REMOVAL METHODS

3.1 Background

To remove a fixed platform, the installation steps are essentially reversed.

Topside equipment such as living quarters, generators, and processing equipment is taken

off by crane and returned to shore for scrap or to be reused (see Figure 2.1). The deck

sections are then lifted from the platform and placed on cargo barges for transportation to

their disposal site. Conductors, flare piles, submerged wells, and caissons also are

structures subject to explosive removal (see Chapter 6). MMS regulations require that

the piles and well conductors be severed at least 5 m (15 ft) below the mud line and

removed. Once the piles and conductors are disconnected from the seabed, they are lifted

out and placed on a cargo barge for ultimate disposal.

Pilings and conductors can be cut by a number of mechanical means, including

 use of tungsten-carbide blade cutters contained in routine rig workover

equipment;

 use of diamond wire and hydraulic shear cutters deployed by remotely

operated vehicles (ROVs); and

 manually by divers through the use of mechanical or abrasive cutting

techniques.

The safest and easiest cutting procedure is to place an explosive charge inside the piling

at the desired depth and sever the piling explosively.

Underwater cutting of piles and conductors is a slow and hazardous process

requiring extensive dive time and considerable risk to divers. Mechanical cutting also is

not as reliable as explosive cutting, and the risk of failure is considerably higher than that

associated with explosive techniques (Kaiser et al. 2002).

An Environmental Assessment (EA), prepared pursuant to National

Environmental Policy Act (NEPA) of 1969 (42 U.S.C. 4321-4347) guidelines, as

amended, is conducted for each platform removal application received by the MMS. In

1987, a programmatic EA was prepared by the MMS to assess the entire spectrum of

potential environmental impacts associated with platform removal (MMS 1987). A

site-specific EA is prepared for each individual platform removal proposal, with tiering

off of the programmatic EA and containing site-specific environmental details from the

specific site, and operational procedures for a specific platform removal effort

(Richardson 1989). MMS is presently preparing an updated programmatic EA to

consider explosive removal operations in all water depths. If explosives are used to cut

the pilings and conductors during platform removal, there is the potential that sea turtles

or other endangered or protected species (i.e., marine mammals) in the area could be

harmed, as detailed previously in Chapter 2.
34

3.2 Presently Employed Explosive Cutting Techniques

3.2.1 Bulk Explosive Charges

The most commonly used technique for explosive cutting of piles and conductors

is with bulk explosives such as C-4 or Comp B (Figure 3.1). These explosives are

castable and moldable, have a high velocity on detonation, and a high shattering power.

They are not as dangerous to handle as some other types of high explosives, and they can

be molded in the field to specifically required sizes and shapes. This moldability

characteristic is an important advantage explosive techniques have over conventional

cutting techniques. During platform construction, piles are welded together with steel

guides, called “stabbing guides,” on the inside bottom of each pile section to facilitate

mating with the next section. This reduces the inside diameter of the pile both above and

below the weld. These inside pile diameter reductions are critical when using

conventional cutting techniques where equipment must be lowered down the pile and

then retrieved after the cut is made. When using bulk explosives, these variations in pile

diameter are a relatively minor inconvenience. Bulk charges can be sized to sever a pile

in the field and do not have to be retrieved. Bulk charges also can be re-shaped in the

field when discrepancies between the “planned” and the “as built” diameters of piles or

well strings are encountered. This flexibility is important because it allows jobs to

proceed with relatively little delay.

Bulk charges are lowered into prepared pilings or well conductors and detonated

nearly simultaneously with a 0.9-sec delay in groups of eight or less (Figure 3.2). After

an eight charge detonation sequence, there is a pause. While there is no legal or

permit-associated required length for this pause, contractors will usually pause 2 to

3 minutes before the next detonation sequence is initiated (W. Poe 2003, pers. comm.).

On a normal platform, all piles and wells can be severed within an hour or two, including

the time required for loading the charges and conducting the NOAA-F required aerial

surveys for sea turtles and marine mammals.

Bulk explosives have a 95% success rate when sized properly. Increased water

depth has no adverse impact on the success rate of bulk explosive cuts. If a bulk

explosive does not sever a piling or well string on the first detonation, a back-up charge

can be sized and deployed quickly. After more than a quarter century of use and

hundreds of thousands of worker-hours, no serious injuries have been reported for

handling or using bulk explosives in platform removal (NRC 1996).

3.2.2 Configured Bulk Charges

Configured bulk charges such as “ring charges” and “focusing” charges are

designed to collide or “focus” the detonation front to concentrate more energy along the

fracture line, and thus reduce the size of the charge needed to cut a piling. These types of

charges have been effective in reducing “belling” or bulging out of the severed piling.
Figure 3.1. Bulk explosive charge (From: DEMEX 2002).

HARNESS

LEAD-IN

BOOSTER

MAIN CHARGE
Figure 3.2. Bulk charge arrangement for larger diameters (From: DEMEX 2002).

EXPLOSIVE

EXPLOSIVE

4-5" X 10 lbs 5" X 40 lbs

TOP VIEW
37

Ring Charges

Ring charges (Figure 3.3) are made from the same material as bulk charges,

primarily C-4 or Comp B formed into doughnut-shaped rings, which are lowered into the

piling. These rings concentrate the explosive closer to the inside of the piling’s walls,

making it more effective. Ring charges can reduce the total weight of charges required to

sever a specific piling by approximately 10% to 15% (NRC 1996).

Focusing Charges

Focusing charges (Figure 3.4) consist of explosives sandwiched between two

“tamping” plates, one above and one below. These tamping plates have the effect of

delivering more of the explosive’s power horizontally to the piling walls and thus

allowing the use of smaller charges. Reductions in explosive weight with focusing plates

are comparable to reductions in weights associated with ring charges.

The drawback with both ring and focusing charge arrangements is that both must

be prefabricated and sized to fit each application. Generally, there is some size variation

built into each configuration, which will allow for minor variations of inside pile

diameters or obstructions. Configured charges cannot be used to sever wells because the

diameter of the inner casing is too small to accommodate the charge (NRC 1996).

3.2.3 Cutting Charges

Cutting charges include linear-shaped charges and “cutting tape.” Each of these

is discussed in greater detail below.

Linear-Shaped Charges

Linear-shaped charges use high-velocity explosive energy to accelerate a

v-shaped band of cutting material, usually copper, in a high velocity jet that penetrates

through the steel of the piling. Linear-shaped charges can be used in specifically

manufactured containers that fit around the outside of the piling to cut pilings from the

outside (Figure 3.5). Linear-shaped charges can also be positioned on the inside of

platform legs using a running tool or articulated device for positioning the charge

(Figure 3.6).

The performance of linear-shaped charges depends on the presence of an air space

between the charge and the target. This required “stand-off” distance is a function of the

thickness of the material to be cut. When accurately positioned to a precisely calculated

stand-off distance between charge and target, linear-shaped charges yield very smooth

cuts (NRC 1996).

Linear-shaped charges require long lead times to fabricate and accurate

engineering data on the piling or caisson to be cut. If the thickness of a pile section is

unknown (not unusual in older oil field structures), or if the pile is out of round,
Figure 3.3. Configured bulk "ring charge" (From: DEMEX 2002).
Figure 3.4. Focusing charge (From: DEMEX 2002).

EXPLOSIVE IS

SHOWN IN BLACK

CONCRETE

STEEL
Figure 3.5. External linear-shaped charge (From: DEMEX 2002).

Pile

Explosive
Figure 3.6. Internal linear-shaped charge (From: DEMEX 2002).

Pile

Explosive
42

linear-shaped charges will not produce clean cuts. If linear-shaped charges are placed on

the outside of a piling, any attenuation in the explosive force offered by the soil is lost.

To be used on the inside of a piling, linear-shaped charges must be articulated to pass by

the stabbing guides, and if a stabbing guide is located at the elevation of the proposed cut,

a clean cut cannot be obtained. Also, if water or soil infiltrates the air space of the

stand-off distance, charge performance is greatly reduced.

Cutting Tape

Explosive cutting tape is a flexible version of the linear-shaped charge

(Figure 3.7). The explosive and the liner are extruded into a shaped charge housed in a

flexible conductor that allows the tape to be contoured to the pile, thus maintaining the

proper stand-off distance around the entire pile.

The disadvantages of cutting tape are two-fold:

1) Divers are required to place the tape around the target pile; and

2) Because the charge and liner are positioned in the conductor at the surface,

at depths greater than 91 m (300 ft), ambient pressure may cause the

conductor to deform, thus changing the stand-off distance and reducing

the charge cutting efficiency.

At this point in time, cutting tape is not as efficient as linear-shaped charges for

platform removal, especially at depths greater than 91 m (300 ft) (NRC 1996).

3.3 Potential Future Explosive Cutting Techniques

3.3.1 Contact Plaster Charges

Contact plaster charges are placed directly on the steel pile to be cut. The

explosion causes a pressure wave to propagate through the pile thickness, and spalls or

fragments some of the steel on the opposite side of the pile when it is reflected as a

tensile wave. Pressure from the expanding gas completes the cut. This type of charge

would reduce the charge weight but would have to be deployed in a cutting tape form by

a diver. Shock refraction charges are the same size as plaster charges but are shaped like

a shaped charge in cutting tape form. With shock refraction charges, compressibility is

not a factor because the explosive is placed directly against the steel piling. There is no

stand-off distance requirement because the pressure wave does the cutting. Diver

placement is still required.

3.3.2 Shock-Wave Focusing Charges

Shock-wave focusing charges (Figure 3.8) are hollow charges flexible enough to

be wrapped around tubular platform members internally or externally. These charges

focus the energy of the shock-wave through a steel piling, and by exerting very high

compressive/tensile stresses on the target area, initiate controlled brittle fracturing.
Figure 3.7. Flexible linear-shaped charge (From: DEMEX 2002).

Pile

Explosive
Figure 3.8. Shock-wave focusing charge (From: National Research Council 1996).

I

I

R R

Wave guide

Explosive

R = Reflected shock from back surfaceI = Incident shock from wave guide
45

Shock-wave focusing can reduce the explosive weight of a cutting charge by up to

90% when compared with standard shaped charges. Shock-wave focusing charges are

particularly effective for targets with thicker walls, but to be effective, they require that

the opposite surface be backed by either water or air. Grout-backed surfaces are not

effectively severed by shock-wave focusing methods.

3.3.3 Radial Hollow Charges

Radial hollow charges (Figure 3.9) are short, linear-shaped charges bent into an

arc with the explosives initiated simultaneously at the central axis. The detonation front

runs radially outward, detonating the explosive simultaneously on both sides of an

inverted v-shaped liner. The liner collapses, producing a flowing radial cutting jet.

Because of this diverging flow, a relatively long cut can be produced in a flat or curved

steel plate. By joining a number of these types of charges together, it is possible to cut

along plates and around pipes using relatively low explosive weights (Figure 3.10).

3.4 Characteristics and Physical Properties of Various Explosives

There are hundreds of commercially available explosives and many variations in

the chemical mixtures of particular types of explosives. Table 3.1 lists the physical

properties of some of the more commonly used explosives. The physics of explosives are

discussed in detail in the following chapter (Chapter 4).

3.5 Developing Technologies

Developing technologies within the industry include both modifications to

explosives and improved mitigation methods. Explosives and explosive devices evolve

based on market needs and regulatory requirements. Several potential improvements in

explosives and explosive devices are listed below.

3.5.1 Improved Explosives

Manufactures are continually developing new and improved explosives.

Applying these new types of explosives to the offshore industry may be one way to

reduce charge size and minimize environmental impacts in the future. At the present

time many new explosive compounds are manufactured in such small quantities that their

large-scale use is cost prohibitive.

3.5.2 Improved Shaped Charges

Several design improvements in shape charges are in the testing phase. Currently

a 5-lb charge limit would be limited to severing a tubular 36 inches or less in diameter.
Figure 3.9. Schematic of a radial hollow charge (From: National Research Council 1996).

Explosive Layer

Initiation Segment

Initiation Point

Liner

Main Charge
Figure 3.10. Radial hollow charges arranged for cutting a leg from outside (From: National Research Council 19
Table 3.1

Physical Properties of Some of the More Commonly Used Explosives (From: DEMEX 2002

Velocity Explosive Principal Use(s) m/sec ft/sec Density Shattering Effect (TNT = 1.0) Water Resistance Spe

Ene

(watt

Black PowderBlack Powder Propellant 400 1,320 1.6 0.1 Poor Primary Initiating ExplosivesLead Azide Detonator Primer 5,300 17,400 5 0.39 Fair 46Diazodini –trophenol(DDNP)

Detonator Primer 6,600 21,700 1.63 0.92 Fair 

Lead Styphnate Detonator Primer 5,200 17,000 2.9 0.4 Fair 47Secondary High ExplosivesPentaeythritoltetranitrate(PETN)

Shape ChargesDetonating CordMetal Severance

8,400 27,600 1.7 1.73 Good 67

Cyclonite(RDX)

Demolition ChargeShape ChargesDetonating CordMetal Severance

8,750 28,700 1.76 1.57 Good 67

Homocyclonite(HMX)

Demolition ChargeShape ChargesMetal Severance

9,100 29,800 1.91 1.45 Good 66

Trinitrotoluene(TNT)

Demolition ChargeShape ChargesCratering and Rock

Removal

Detonating CordMetal Severance

6,900 22,600 1.65 1 Good 48
Table 3.1. Physical Properties of Some of the More Commonly Used Explosives (From: DEMEX 2002) (continu

Velocity Explosive Principal Use(s) m/sec ft/sec Density Shattering Effect (TNT = 1.0) Water Resistance Spe

Ene

(watt

AmmoniumPicrate(Explosive D)

Demolition ChargeShape ChargesMetal Severance

7,150 23,500 1.6 1.25 Poor 32

Nitroglycerin(NG)

Demolition ChargeCratering and Rock

Removal

PropellantMetal Severance

7,600 25,000 1.81 1.81 Fair 72

Nitroglycol(NGC)

Demolition ChargeCratering and Rock

Removal

PropellantMetal Severance

7,300 24,000 1.48 2.06 Fair 78

Nitromethane(NM)

Demolition ChargePropellantMetal Severance

6,290 20,700 1.14 1.33 Fair 53

Tertiary High ExplosivesAmmoniumNitrate

Cratering and Rock

Removal

2,800 9,200 1.13 0.6 Poor 28

High Explosive CompositionsComposition B Demolition Charge

Shape ChargeMetal Severance

7,840 25,700 1.68 1.3 Good 

CompositionC-4

Demolition ChargeShape ChargeMetal Severance

8,040 26,400 1.59 1.32 Good 
Table 3.1. Physical Properties of Some of the More Commonly Used Explosives (From: DEMEX 2002) (continu

Velocity Explosive Principal Use(s) m/sec ft/sec Density Shattering Effect (TNT = 1.0) Water Resistance Spe

Ene

(watt

Cyclotol 70/30 Demolition Charge

Shape ChargeMetal Severance

8,060 26,450 1.73 1.31 Good 

Octol 75/25 Demolition Charge

Shape ChargeMetal Severance

8,643 28,350 1.81 1.16 Good 50

Plastic Bonded(PBX9404)

Demolition ChargeShape ChargeMetal Severance

8,800 28,900 1.86 1.37 Good 

Pentolite 50/50 Demolition Charge

Shape ChargeMetal Severance

7,465 24,500 1.66 1.22 Good 58

Detasheet Demolition Charge

Metal Severance

7,300 24,000 1.62 1.12 Good 49

Torpex(AluminizedExplosive)

Demolition ChargeShape ChargeMetal Severance

7,500 24,600 1.81 1.64 Good 86

Blasting Gelatin Demolition Charge

Shape ChargeMetal Severance

7,300 24,000 1.5 1.91 Fair 74

HTA-3AluminizedExplosive

Demolition ChargeShape ChargeMetal Severance

7,870 25,800 1.9 1.19 Good 57

Commercial Dynamites40% NGDynamite

Cratering and Rock

Removal

- - - - Fair 
Table 3.1. Physical Properties of Some of the More Commonly Used Explosives (From: DEMEX 2002) (continu

Velocity Explosive Principal Use(s) m/sec ft/sec Density Shattering Effect (TNT = 1.0) Water Resistance Spe

Ene

(watt

50% NGDynamite

Cratering and Rock

Removal

- - - - Fair 

60% NGDynamite

Cratering and Rock

Removal

- - - - Fair 

Binary ExplosivesBinex 42P Demolition Charge

Cratering and Rock

Removal

4,000 13,125 1.5 - Good 

PLX (Liquid,Liquid)

Demolition ChargeShape ChargeCratering and Rock

Removal

Metal Severance

6,200 20,340 1.14 1.27 Good 53

Kinepak (Solid,Liquid)

Demolition ChargeCratering and Rock

Removal

Metal Severance

6,100 20,010 1.15 - Good 
52

3.5.3 Improved Charge Deployment Devices

Charge deployment devices are at the root of many of the problems discussed

previously concerning charge placement and effectiveness. Unfortunately, since charge

deployment devices are essentially expendable (being blown up with the charge), large

investments in their development are rarely undertaken. The market for sophisticated,

expensive charge deployment devices is limited.

3.5.4 Computer Modeling

There are several computer modeling developmental programs aimed at

developing a better understanding of the best way to induce tubular failure. Once

perfected, such computer modeling programs may allow contractors to better calibrate

their explosive requirements and reduce the size of charges required for specific jobs.

3.5.5 Improvements in Explosive Cutting Tape

Explosive cutting tape is a type of linear shape charge. The flexibility of the tape

allows it to be contoured to irregularly shaped platform members and still maintain the

required stand-off distance for an effective cut. At the present time, the compressibility

of this type of flexible linear charge makes it ineffective in deeper water where the

hydrostatic pressure causes the liner to be distorted or collapsed. Improvements in the

flexible casings for these types of charges could allow them to be used at greater depths.

3.5.6 Fracturing Charges

“Plaster” and “Shock Refracting” charges do not require the specific stand-off

distance of a shaped charge, thus avoiding the compressibility problem. Charge weight

for specific tubular cuts currently is difficult to calculate, but improvements in computer

modeling may help with this problem. At the present time, these charges must be

deployed by divers, making them difficult and expensive to use in deep water. There is

the potential that ROVs and autonomous underwater vehicles (AUVs) could be employed

or specifically developed to deploy these type charges in very deep water.

3.5.7 Shock-wave Focusing Charges

This method produces very high compressive stresses on the target material,

which rapidly converts to tensile stress, and causes controlled brittle fractures. Tests

conducted in air suggest that explosive weights required to cut specific size tubulars

could be reduced as much as 90% compared to bulk charges using this method. This

method requires the side of the target opposite the charge be backed by air. Because of

this requirement, it is thought that shock-wave focusing charges will be ineffective at

greater depths.

3.5.8 Radial Hollow Charges

Use of radial hollow charges would allow a low explosive-to-target ratio because

they produce a diverging energy flow allowing a long cut on curved surfaces. However,

this type of charge is difficult to place in deep water.
53

CHAPTER 4

PHYSICS OF UNDERWATER EXPLOSIONS

4.1 Underwater Explosive Source Characteristics

4.1.1 Explosive Process

The majority of explosives used in underwater demolition work contain oxygen in

their molecules in a relatively unstable chemical bond. When the explosion is initiated,

this oxygen is readily freed and recombines with other atoms to form more stable

molecules. The explosive reaction is the breakdown of the original molecules into

derivatives, a process accompanied by the release of large amounts of heat.

Detonation and burning, or deflagration, are the two forms of energy release that

can take place, depending on the formulation and conditions of the blasting product.

Detonation is the term for the rapid movement of a pressure front ahead of the chemical

transition front. Formulations such as cyclonite (RDX) and trinitrotoluene (TNT) are

properly referred to as explosives as they are intrinsically capable of detonation. The

former is an example of a primary explosive, for which detonation can be achieved even

in a small quantity of material with a nominal supply of energy such as that from a

detonator cap. The latter is qualified as a high explosive (dynamite being another) in that

it can achieve and sustain detonation only when the charge exceeds a critical volume or

diameter.

The term blasting agent refers to a material that can be made to detonate when

initiated properly, such as ammonium nitrate with fuel oil (ANFO) and water gel slurries.

Blasting agents, like high explosives, require a minimum charge diameter for detonation

– 50 mm diameter with confinement for ANFO, versus less than 20 mm diameter for

some dynamites (Dick et al. 1993). The process of burning or deflagration is a slower

release of the chemical energy of the materials, which does not cause a rapidly expanding

detonation pressure wave. High explosives and blasting agents deflagrate when their

charge diameter or volume is less than the critical threshold for detonation. Materials

such as black powder, commonly categorized as low explosives, only deflagrate

regardless of charge size and initiation conditions.

In a detonating explosive, a physical shock front rapidly compresses the explosive

material and advances significantly faster than the sonic velocity of the material. As this

front passes through the explosive, it triggers the release of chemical energy and thus

realizes a self-sustaining wave that builds up to a stable limiting rate of propagation that

is characteristic of the detonating material. This self-sustaining wave, known as a

detonation wave, differs from a shock wave propagating through a non-reacting medium

in that the conditions behind the shock front are affected by the energy released by the

chemically transformed matter, and the wave is driven not by the motion of a boundary

surface some distance behind the shock but by the internal conditions of the material

immediately behind the front. This process is only sustained within the limits of the
54

explosive material, and ceases at the boundary with the medium containing the explosive.

A conventional shock wave then passes into the surrounding medium.

Beyond a short distance from the blast, generally taken to be three to ten

diameters of the explosive’s charge, thermal and direct detonation effects from the

explosion can be ignored; the main sources of impact outside this distance are the shock

wave and the expanding gaseous reaction products. The original shock wave is the

primary cause of harm to aquatic life at great distances from the shot point; the expanding

gases, if they do break into the water column from the substrate where the explosion

occurs, can set up a pulsating bubble whose recurring pressure waves may also contribute

significantly to damage. These phenomena will be discussed in later sections in the

context of their relevance to the process of explosive removal of structures; a more

exhaustive and general treatment of underwater blasting may be found in Cole (1948).

4.1.2 Shaped Charges and Directionality

In operations of explosive removal of offshore structures, most of the structural

members to be severed are cylindrical metal structures protruding from the bottom

sediment; these can be support legs, piles, or well conductors. The use of shaped

charges, especially linear-shaped charges, is a well-established method (Al-Hassani

1988) for applying maximum cutting power to the surface of the object while minimizing

the dispersion of explosive energy in ineffectual directions. A linear-shaped charge is a

high explosive contained behind a metal sheath liner in the shape of an inward wedge; in

tubular structure cutting, the charge is curved into a ring that fits either inside or around

the structure so that the liner forms a V-shaped groove facing the surface to be cut. On

detonation, the liner collapses and is projected toward this surface as a high-velocity

metal jet traveling at about 2-3 km/s. The jet tends to converge and concentrate the

energy onto a thin cutting line. One of the major challenges in the underwater use of

shaped charges is the requirement for an air medium along the path of the cutting jet, as

the efficiency drops significantly if the jet must pass through even a short distance of

water. This is usually accomplished by incorporating an air chamber between the charge

and the target surface in the design of the explosive casing.

A related method that, while not actually involving a shaped charge design, also

makes use of detonation front dynamics to increase cutting effectiveness is the

simultaneous detonation at both ends of a cylindrical charge lowered inside a casing

(Al-Hassani 1988). In traditional underwater blasting of a solid substrate for material

clearing, the practice is to initiate the shot at the deepest point of a charge inserted in a

hole drilled in the rock (Keevin and Hempen 1997). The detonation front then

propagates up the explosive column, focusing the shock energy primarily in that

direction, with less energy being transmitted radially and only a small percentage

emanating opposite the detonation direction (Konya and Walter 1985). For the purpose

of cutting a tubular casing with a severance charge, on the other hand, the greatest

effectiveness is achieved by initiating a detonation front at each end of a cylindrical

charge. The two fronts meet at the center of the charge and produce double the impulsive

pressure responsible for cutting through the surrounding metal wall, effectively focusing

the energy release toward a smaller target area, much like a shaped charge would.
55

From the standpoint of environmental effects mitigation, these detonation

techniques are advantageous in that they enable explosive structure cutting work to be

performed with smaller charge weights and thus with less overall release of energy in the

surrounding medium. The directionality pattern of the acoustic levels in the far field,

however, is not appreciably affected by the shaped-charge detonation dynamics and is

chiefly dependent on the overall geometric dimensions of the charge relative to the

wavelength of sound at frequencies of interest. For the purpose of discussing directivity,

we can assume that all sections of the charge detonate simultaneously. Directionality

functions in the plane of charge distribution can be readily computed for a line charge

and for a uniform rectangular charge configuration. The line charge directivity is given

by

, sin , where sin ( , )

c

u f L

u

u D f     

L is the length of the line, and  represents the angle measured from broadside (at right

angles to the line). The directivity function for a rectangular distribution is the product of

the directivities of two perpendicular line charges, which gives

, cos , sin , where sin sin ( , ) 1 2

c

v f L

c

u f L

uv

u v D f 



    

and L1 and L2 are the length and width of the rectangular charge. For the circular

explosive distribution of the charges used for pile cutting, as intuition would suggest,

there is no acoustic directionality in the horizontal plane. In the vertical plane, the

acoustic level at a given frequency will exhibit a significant directivity pattern only if the

linear size of the charge is comparable to the acoustic wavelength in the medium;

directionality will therefore always diminish at lower frequencies. At a sound frequency

of 750 Hz, the wavelength is approximately 2 m in water and longer yet in a mud layer

with higher acoustic velocity, meaning that only charges having geometric dimensions of

that order will exhibit appreciable vertical directionality. This would be the case with the

ring charges used for severing tubular platform legs that can be several meters in

diameter. As ring charges are installed horizontally to cut risers, the highest sound levels

will be projected in the water column directly above them — the main directional lobe

being broadside to the plane of the ring. The acoustic levels measured in the water

column off the vertical would then be lower than predicted on the basis of propagation

range alone.

4.1.3 Media Considerations

The location of the explosive in the surrounding media is of the greatest influence

in determining the acoustic levels generated in the water column by an underwater

detonation. Open-water shots, in which an unconfined explosive is detonated within the

water column itself, are not part of the current practice for explosive removal of offshore

structures, as regulations specify a minimum depth of 5 m (15 ft) below the mud line for

any charge used to sever a structural component (Richardson 1989). The acoustic impact

of the buried charge explosion, however, can vary significantly depending on the nature
56

of the sediment and could range in principle from an essentially waterborne detonation to

a completely confined shot with no venting of explosion gases into the water column.

The presence of the metal structure being severed, which may act as containment and will

absorb a portion of the explosive energy, further complicates the scenario compared to

the detonation of a free charge in the sediment. Generally it is safe to assume that

ignoring the effects of the structure will yield a conservative “worst case” assessment of

the impact from the detonation, and there is evidence (Nedwell et al. 2001) that the

extremely high detonation forces in close proximity of the charge so far exceed the

strength of the metal structure as to make its influence negligible.

The physics of shock and acoustic wave propagation from a detonation will be

presented in a later section. Here we want to introduce empirical relations that predict the

acoustic level at a given range from the detonation in order to discuss how the positioning

of the charge in the sediment layer alters the expected impact relative to the open-water

case. For a detonation in the free water column, assuming no source directionality

effects, the peak pressure in the near-field is given in terms of the range r in meters and

charge weight W in kilograms by the well known relation

2

1/ 3

7

0 5.24 10 N / m

















  

r

W

p ,

where the exponent α is the attenuation coefficient in water, α ≈ 1.13. A derivation based

on ray theory (Powell 1995) extends this relation to the case of peak pressure from a

charge buried a distance b below the sediment surface, measured at a point distance a

above that surface (r still being the slant range between source and measurement point):

2

1/ 3

7

0 5.24 10 N / m







 



 















 	 

b

a b

r

W

p ,

where ε is the bottom attenuation coefficient. Based on full-scale measurements carried

out by Connor (1990) during a Gulf of Mexico platform removal, Powell (1995)

estimated ε ≈ 1.99 for a compact mud bottom. It is readily observed that the above

formula correctly reverts to the open-water case in the limit for ε → α (the sediment

attenuation tends to that of water). This also signifies that in low-density sediments, the

influence on peak pressure of deploying the charge below the mud line could be

insignificant, a fact borne out by field measurements during a North Sea platform

removal operation (Nedwell et al. 2001) where the peak pressure in the water column

from pile-cutting detonations below the sediment surface was found to match the

open-water estimates. The equation above provides a more definite estimate of peak

pressure in the water column due to explosions below the mud line than the often taken

approach of merely bracketing the estimate between the value for an open-water shot and

that for a fully confined explosive embedded in rock (generally taken to be 5% to 10% of

the open-water case). The expression also is consistent with the physics of wave

transmission at the bottom-water interface as, for a given range between source and

receiver, the peak pressure estimate increases with receiver height above the bottom.

This can be seen to correspond to the increase in energy coupling efficiency as the angle

of incidence approaches the normal.
57

4.1.4 Multiple Charges

The practice of cutting several of the supporting piles of a platform by detonating

multiple charges at once was adopted in the past as an efficient removal procedure.

Al-Hassani (1988) mentions a 1983 decommissioning operation in the Gulf of Mexico in

which all the piles were cut simultaneously by linear-shaped charges, causing the

conductor to settle on its mud mats to be later floated using buoyancy tanks. This type of

procedure was since prohibited by operational restrictions introduced in 1988 that include

a minimum delay of 900 milliseconds between detonations as well as a limit of eight

detonations in a group (Richardson 1989). Nonetheless, it is important to examine briefly

how multiple detonations contribute to the overall pressure levels in the water column.

In the acoustic approximation, where it is assumed that the pressure front from the

detonation has decayed sufficiently in strength to propagate as a sound wave, the pressure

at any point through which two waves from different sources overlap is simply the sum

of the independent pressures from each disturbance. The argument does not apply to the

combination of shock waves in the near-field of two detonations, because the properties

of one shock front will change as it propagates through fluid that has already been

affected by another shock. This leads to the formation of reflected shocks and the

creation of regions of significantly higher overpressure than would be found behind a

single shock. In the practice of underwater detonation for structure removal, however,

such shock interaction phenomena would only affect a relatively small region in the

proximity of closely spaced and simultaneously exploded charges. For the majority of

the propagation volume, the acoustic approximation would apply.

When estimating the acoustic pressure levels from simultaneous or nearly

simultaneous detonations, the relative positions of the respective charge locations should

be considered. When the charges are spaced at greater distance than a few wavelengths

for the specific frequencies of interest (the spectral regions where acoustic energy is

strongest), then the resulting energy flux density (EFD) levels in all directions can be

assumed to be simply the sum of the individual EFDs (incoherent sum). If the charge

spacing is less than or comparable to a wavelength, then a coherent approach should be

taken. This involves treating the distribution of charges as an acoustic array that has

directional characteristics. The incoherent sum of EFDs must then be corrected using the

system directivity function. Although the pattern of directional lobes depends on the

array geometry, as a rule the directions of strongest output will be perpendicular to planes

in which the charges lie. If in the operation mentioned earlier the legs of the platform

were cut by simultaneously detonated charges all at the same depth, the directions of

maximum sound output would be straight up and down. With the regulatory limitation of

nearly 1 second minimum interval between detonations, on the other hand, such

considerations are no longer of practical concern as the sound level pattern from a single

charge would not be affected by the interaction with others.
58

4.2 Shock Wave and Acoustic Propagation

The manner in which shock and acoustic waves propagate from the source into

the ocean is strongly influenced by the ocean environment. Noise propagating in shallow

water environments, where depth is less than a few hundred meters, can reflect many

times from the sea surface and bottom. In these cases, sea surface roughness and sea

bottom characteristics are often very important. Fewer surface and bottom interactions

occur in deeper water. However, refractive effects due to differential temperature and

salinity profiles can cause sound to be trapped in small depth channels and can lead to

sound focusing. This section discusses how sound produced by removal operations

propagates away from the operation site and ensonifies the surrounding sea.

4.2.1 Pressure Waveform

The pressure wave of underwater explosive detonations is composed of a shock or

primary pulse followed by a series of bubble pulses. The shock pulse has rapid rise time

and exponential decay, as is discussed in following subsections in this chapter. This

high-pressure pulse is due to the rapid conversion of solid explosive to gaseous form.

The gas bubble initially expands due to its very high pressure. It eventually reaches and

overshoots the volume corresponding to ambient water pressure due to the radially

outward momentum imparted to the surrounding water. The negative-phase pressure

following the shock pulse is due to the overshoot. Eventually the bubble reaches a

maximum volume, corresponding with the minimum of the negative phase, and then

starts to collapse. It reaches a minimum volume that corresponds with a second peak in

the pressure waveform, referred to as the first bubble pulse. This oscillatory behavior

continues, albeit with successively lower amplitude pulses as energy is lost to heat

dissipation. Figure 4.1 shows the recorded waveform from a 0.82 kg charge detonated at

193 m depth. It clearly shows the features of the explosive waveform described here.

4.2.2 The Near-Field

The near-field is the region close to the detonation location where the pressure

wave has sufficiently high amplitude that particle displacements are not always

proportional to pressure. In this region, the shock pressure front pre-conditions the

medium by heating and compression, so that acoustic waves behind it travel more

quickly. The acoustic waves catch up to and reinforce the shock front, thereby sustaining

its high pressure. The explosion pressure pulse is referred to as a shock wave in the

region close to the source where the shock front persists. The shock pressure decreases in

amplitude as it moves further from the source due to geometrical spreading and heat

dissipation. The peak pressure eventually drops to levels at which the non-linear effects

cease. Afterwards, all parts of the pressure pulse propagate at the same speed, and the

signal is then referred to as an acoustic wave.
59

Figure 4.1. Pressure waveform from a 0.82 kg SUS charge detonated at 193 m

(Reproduced from: Hannay 1995).

Measurements of pressure waveforms in the very near-field show that shock pulse

pressure as a function of time p(t) is described quite accurately by an exponentially

decaying function of the form:

( ) exp( / ) 0 0 p t p t t

where p0 is the peak pressure associated with the shock front and t0 is a time constant for

exponential decay. Explosion shock theory has proposed specific relationships for the

peak pressure and time constant in terms of the charge weight and range from the

detonation position. These theoretical relationships have been confirmed by

measurements of pressure waveforms from a wide variety of TNT charge detonations:

2

1.13 1/ 3

7

0 5.24 10 

 N / m











  

r

W

p

9.25 10 sec

0.22 1/ 3

5 1/ 3

0



















  

r

W

t W ,

where W is the charge weight in kilograms and r is the distance from the source in

meters. These equations are valid only in the near-field of the explosion. A limiting

range for their validity has been suggested to be 1/ 3

0r  4.76W meters (Gaspin 1983). At

ranges greater than 0r , the expressions for peak pressure and time constant must be

modified. Rogers (1977) proposed the following modifiers for peak pressure and time

constant for 0 r  r , based on weak shock theory:
60

( ) ( ){  1 2( / )ln( / ) 1}/ ( / )ln( / ) 0 0

1/ 2

0 0 0 0 0 0 0 p r  r  p r r L r r  r L r r

 1 / 2

0 0 0 0 0 0 0 t (r  r ) t (r ) 1  2 (r / L ) ln( r / r )

where 0 ( 0 ) / 0 ( 0 ) 3

0 L  c t r p r ,  is the density (1,026 kg/m3 for sea water), c is the

sound speed (1,500 m/s),   3.5 , and ) ( 0 0 p r and ) ( 0 0 t r are computed from the

near-field equations above.

4.2.3 Sea Surface Reflections

The smooth sea surface is a strong reflector of acoustic energy at nearly all

frequencies. The reflection coefficient is close to negative one, indicating that

180-degree phase reversal occurs upon reflection. This means that incident pressure

pulses will be reflected with reversed polarity. This effect is apparent in Figure 4.2,

which shows the direct path and surface reflected signals from a charge detonated at 23 m

depth. The waveform in this figure also exhibits the effect of cavitation, which can occur

upon reflection of high-pressure shock pulses at the surface. Cavitation happens when

the reflected pulse pressure drops below -1 atmosphere (-101 kPa). When this happens,

the strongly negative pressure wave causes water to vaporize, creating small bubbles.

The surface-reflected shock pulse signal in Figure 4.2 is truncated due to this effect. It

also is followed by a short period of high-frequency noise produced by oscillations of the

cavitation bubbles. It is noted that the cavitation effect is not noticed in the surface

reflections of the lower-amplitude bubble pulses in Figure 4.2.

Figure 4.2. Pressure waveform for 0.82 kg SUS charge detonated at 23 m. Waveform

shows reversed-polarity surface reflections (From: Hannay 1995).
61

Sea surface roughness causes scattering of sound upon reflection. Furthermore,

entrapped bubbles near the surface due to breaking waves can absorb acoustic energy and

also can scatter reflected energy. These effects tend to reduce the amplitude of the

reflected signals. The scattering and absorptive effects of rough surfaces become

important when the dimension of the roughness is comparable to or larger than the

wavelength of the reflected sounds. Consequently, roughness generally has greater

importance for high frequency (small wavelength) sounds than it does for low frequency

sounds.

When the charge is detonated very close to the sea surface, the reverse-polarity

surface reflected signals can cancel out the direct path signal. This is especially true in

horizontal directions because the two propagation paths are nearly identical in length and

consequently the two signals can arrive nearly simultaneously. If the charge is detonated

at greater depths, then the two signals may partially overlap, causing either constructive

or destructive interference. The source signal strength pattern is a function of angle

measured from horizontal, frequency, and source depth. This interference effect is

known as the Lloyd mirror effect (Officer 1958).

4.2.4 Sea Bottom Reflections

The sea bottom, or seafloor, is a reflector of acoustic energy. The impedance

contrast between water and bottom materials, however, is less than between water and air

at the sea surface. Consequently, a large fraction of acoustic energy incident on the

seafloor will be transmitted into the bottom where it may reflect from subbottom layers.

A full discussion of the physics of multi-layer reflections is beyond the scope of this

report; however, an excellent synopsis may be found in Brekhovskikh (1980) (see

“Waves in Layered Media” [Brekhovskikh 1980] for an in-depth treatment of this

subject). For the purposes of the present discussion, it suffices to consider composite

reflection coefficients that encompass the energy reflected from all bottom layers.

Seafloor reflection coefficients range from about 0.1 to 0.5 at steep angles of incidence

and can increase to nearly 1.0 at very shallow angles. Rough ocean bottoms tend to

scatter energy, similarly to rough sea surfaces, thereby reducing the reflection coefficient

for high frequency sounds. It is noted that the bottom reflection coefficient is real and

positive at steep angles, but is often complex for shallow angles. Complex reflection

coefficients distort the shape of the reflected wave.

4.2.5 Long-Range Propagation

Sound levels at significant distance from underwater explosions can vary

considerably depending on the depth of the explosion, the depth of charge burial, and the

characteristics of the ocean environment. Acousticians have simplified the propagation

problem by introducing the sonar equations. A simplified version of the sonar equations

divides the problem into three primary components: Source Level, SL; Transmission

Loss, TL; and Received Level, RL. They are related through the basic equation:

RL = SL - TL
62

The source level indicates the strength of the source in decibels. It is by convention

referenced to the sound level at 1 m from the charge. Normally, SL is determined by

measuring or modeling the pressure at a practical distance, and then scaling this value

back to 1 m range by adding a spherical spreading loss scaling correction, typically

20 log r, where r is the distance at which the measurement or model prediction is made.

TL is the parameter that quantifies how the medium reduces the sound level as the

signal propagates from the source to the receiver. This parameter includes the effects of

surface and bottom reflections, as well as any refractive effects occurring in the water

itself. Prediction of TL can be a very complex problem because it is dependent on all

characteristics of the sea surface, water column, and sea bottom as well as the locations

of source and receiver relative to the bottom topography. Several computer codes have

been developed specifically for predicting TL based on specific acoustic and geo-acoustic

input parameters. These codes are referred to as propagation models and are based on

several different mathematical approaches. Each of the presently available approaches

has specific advantages and disadvantages, as summarized in Table 4.1.

Table 4.1

Acoustic Propagation Modeling Approaches and Their Respective Advantages and

Disadvantages

Model Type Approach Advantages Disadvantages

Ray Theory Tracks rays

perpendicular to wave

fronts through the

water.

Can model range-dependent

situations in shallow or deep

water, accurate for high

frequency sound; provides

time domain results.

Gaussian Beam versions

improve accuracy for low

frequencies.

Less accurate than

other methods for

modeling low

frequency refractive

effects, especially

near caustics (sound

convergence loci) and

for multi-layer

bottom problems.

Normal Mode Computes single

frequency transmission

losses by summing

mode functions

representing

propagation resonances.

Accurate for low

frequencies, very fast

computation times for long

range propagation, range

dependence can be achieved

under certain assumptions.

Not well suited for

high frequencies

and/or deepwater

cases.

Wavenumber

Integral

Computes transmission

loss for single

frequencies by

decomposing the

problem into plane

wave components that

can be solved

analytically.

Accurate and fast for low

frequencies and most depth

regimes.

Handles range

independent cases

only; computationally

expensive for very

long ranges.

Finite

Difference

Solves the wave

equation on a

computational grid by

calculating derivatives

of the pressure field

directly.

Very well suited for rangedependent problems (see

Figure 4.3); parabolic

equation and split-step

versions are computationally

efficient for low frequencies.

Not well suited for

high frequencies due

to computational grid

resolution

restrictions.
63

Figure 4.3. Example sound field calculations produced using the parabolic equation

finite difference propagation model.

Alternate rule-of-thumb methods have been devised to obtain rough estimates of TL. For

example, Marsh and Shulkin presented semi-empirical formulae for estimating TL in

shallow water for frequencies between 100 Hz and 10 kHz (see Urick 1975). These

formulae utilize tables of correction factors to account for frequency-dependent

absorption and different sea-states and bottom types. The steadily increasing availability

of fast computing platforms to perform detailed numerical modeling is making the use of

these approximate estimation methods less and less justifiable in impact prediction

studies.

4.3 Sound Metrics and Injury-Mortality Criteria

4.3.1 Metrics

Sound level metrics are parameters that quantitatively describe the characteristics

of sound pressure waves at a given spatial location. The commonly used metrics for

impulsive sounds describe the amplitude, energy and time-related characteristics of the

pressure wave. The values of specific metrics are used to gauge the degree of impact that

underwater sound signals have on marine wildlife. Standard thresholds for the metrics

have been established in reference to the minimum levels at which specific impacts have

been observed to occur for given species.

The metrics that need to be considered for gauging one type of impact may differ

from the metrics used for another type of impact. For example, very high-amplitude

pressure pulses, indicated by large values of the peak pressure metric, may cause

differential tissue displacement that can disrupt cells and tissues. On the other hand,

prolonged medium amplitude sounds, such as sounds from underwater drilling, can cause
64

injury to hearing systems. The impact on hearing is better classified by the metrics

root-mean-square (rms) and EFD.

Impulsive sounds arise from short duration events such as explosions and airgun

shots. These sounds are characterized by relatively high amplitude, short duration

pressure waveforms. The following are the most common metrics for impulsive sounds:

 Peak pressure: The highest pressure attained by a sound pressure signal. This

pressure is measured with respect to ambient pressure, and also is referred to

as zero-to-peak pressure.

 Peak-to-peak pressure: The difference between the highest pressure and

lowest pressure over the duration of a waveform. For impulsive sounds

produced by blasting, the lowest pressure is generally negative with respect to

ambient pressure and occurs soon after the largest positive peak due to

expansion imparted to the water by its positive impulse.

 Impulse: The time integral of pressure through the largest positive phase of a

pressure waveform. It has units of Pascal seconds.

 Root-mean-square (rms): The square root of the mean square pressure over

the duration of the impulsive waveform. The duration used strongly

influences the value of this metric, though its definition is sometimes quite

ambiguous. Recent methods have been proposed for determining the duration

based on the cumulative EFD function.

 Energy flux density (EFD): The total acoustic energy propagated through a

unit area normal to the direction of propagation. The EFD of plane waves can

be computed as the time integral of squared pressure, divided by the acoustic

impedance of the medium:

  p dt

c

1 2 EFD

 .

For plane waves, the acoustic impedance is simply the product of sound speed

c and density . EFD has units J/m2

. EFD is not suitable for continuous-wave

sounds because the integral is not normalized in time. A similar metric,

acoustic intensity, divides the expression by the integration time, thereby

producing a metric having units of power per area. The above expression for

calculating EFD is only valid for simple pressure fields that are not

significantly influenced by sea surface and bottom reflections or refractive

effects. However, it is often used when complex pressure fields are present.

A more correct term for the result in those cases is the sound exposure level.

 Sound exposure level (SEL): The time integral of square pressure divided by

the product of sound speed and water density. SEL is commonly expressed in

decibels (dB) as described in the next section.
65

4.3.2 Decibels

All of the above metrics, except for impulse, are normally expressed in decibels.

The decibel presents pressure values on a logarithmic scale relative to a pre-defined

reference level. The sound pressure level SPL in decibels is related to the linear pressure

p (representing either peak, peak to peak, or rms pressure) according to:















 

0

(dB) 20log

p

p SPL ,

where p0 is the reference level. The underwater sound level reference is 1 microPascal

(Pa). Consequently, a pressure pulse with peak pressure of 1 Pa has a peak sound

level of 0 dB. Sometimes this is expressed as 0 dB re 1Pa.

The EFD and SEL metrics are converted to decibels in a slightly different way. It

is noteworthy that these metrics often are used to refer to the same quantity, namely, the

time integral of square pressure divided by the product of sound speed and density. This

definition for EFD, however, is not strictly correct for complex pressure fields. By

looking at SEL, the conversion of both of these metrics to decibels can be demonstrated.

If the SEL is computed as e (in units of J/m2

), then it is expressed in decibels according to















 

0

(dB) 10log

e

e SEL

where e0 is a reference SEL. This reference has been defined as the equivalent sound

exposure produced by a 1 Pa rms plane sine wave over 1 second. Therefore, if signal

pressure p is expressed in microPascals, then the SEL in decibels can be computed

conveniently according to the following:

  SEL  p dt 2 (dB) 10log .

For example: a 1 Pa rms sine wave, having a duration of 10 seconds, has an SEL of

10 dB re Pa. Some authors present this metric in units referenced to (Pa2

 s) or (Pa

s

1/2) to indicate that the actual reference is based on a unit defined by the product of time

and square pressure (in fact the square root of this product). A common alternate

reference unit is 1 erg/cm2

, though that reference has become significantly less common

with the transition from cgs units to SI. The relationship between SEL and EFD

referenced to Pa s1/2 and ergs/cm2

 is

dB re Pa s dB re erg/cm 152 1/2 2   

4.3.3 Frequency Content

None of the above metrics directly provides information about the spectral energy

content of the sound signal. Spectral content is important for some types of impact

criteria. For example, an accepted threshold level for temporary threshold shift (TTS) is

based on exceeding EFD levels of 182 dB re Pa2

s in any 1/3-octave frequency band

(Department of the Navy 2001). The standard approach in this case is to apply frequency
66

domain filtering to the pressure waveform prior to computation of the threshold. This

approach is recommended only for the EFD (or SEL) and rms metrics. A modified

version of the peak pressure metric has also been developed that accounts for the

frequency-dependent hearing sensitivities of specific species. This metric, identified as

dBht(Species), is described below.

4.3.4 dBht(Species)

The dBht(Species) metric expresses sound pressure levels relative to the hearing

thresholds of specific species. It is used most commonly for gauging impacts of

continuous sounds, although it also may be applicable for impulsive noise. This metric

also is referred to as dBha(Species) as defined by Nedwell et al. (1999), where “ha”

represents hearing ability. The dBht(Species) metric is based on the same principle as

frequency weighting schemes used for determining impacts of noise on humans. The

approach is to filter the pressure time series using a filter that represents the

frequency-dependent sensitivity of hearing for the species of interest. Measurements of

hearing sensitivity versus frequency for individual species are known as audiograms.

Audiograms have been measured for many species of fishes and a limited number of

whales. Confidence in the accuracy of audiograms for most marine species is, however,

limited at the present due to the small number of individuals upon which these

measurements have been performed.

The dBht metric is computed by first filtering the pressure function according to

the frequency sensitivity of the species of interest. The resulting time series is analyzed

to determine the peak or rms sound pressure level. A level of 0 dBht should be just

audible, i.e., at the hearing threshold of the species. Since most audiograms are

determined using non-impulsive sounds, we might expect that impulsive or very

short-duration sounds may have to possess peak levels greater than 0 dBht in order to be

perceived. It is also noted that dBht is not an absolute sound level unit. Rather, it

provides a measure of the perceived sound loudness.

When applying the hearing threshold audiogram measures to a potentially

injurious sound or shock wave, one should be cautious about injury caused by

mechanisms other than those having to do with hearing. Consider an animal with poor

hearing at low frequencies being exposed to an extraordinarily high sound pressure at low

frequencies. The audiogram-based dB measures will be much lower than the absolute

pressures and could mislead people into believing that injury was unlikely.

We note finally that sound pressure level metrics for humans are based not only

on frequency-weighted scaling, but also on time weighting. Integrating sound level

meters perform “slow” or “fast” time weightings as standard practice in computing EFD

or SEL metrics. The integration intervals are limited to windows of 1-second (slow) and

1/32-second (fast) during computation of the EFD. This type of time weighting does not

appear to be discussed in the marine mammal literature for computing dBht.
67

4.3.5 Impulse

Impulse I is defined by the time-integral of pressure through the waveform. The

impulse for exponentially decaying shock pulses from underwater explosives (assuming

no interference with surface or bottom reflections) is given by the simple

expression 0 0 I  p t , where p0 is the maximum pressure and t0 is the time constant.

However, for shallow sources or receivers, the arrival of the surface reflection has the

effect of canceling later parts of the direct path shock pressure pulse. Consequently,

impulse calculations are often performed by integrating the direct path pressure only up

to the arrival time of the surface reflection. The time difference Ts between the direct

path and surface reflection can be calculated easily if straight-line propagation of these

paths is assumed:

   2 2 2 2 2 2

0

S

1 R Zs Zr R Zs Zr C

T    ,

where C0 is the sound speed in the water, Zs and Zr are the source and receiver depths,

and R is the horizontal distance between source and receiver.

Goertner (1982) has further modified the integration time by noting that lung

damage in marine mammals occurs primarily from oscillation of the lung cavity.

Goertner’s integration period for calculating impulse is the lesser of the surface reflection

delay and the oscillation period of the lung. Goertner’s model is proposed only for

marine mammals and is not valid for fishes. According to Goertner’s approach, modified

for Standard International units, the lung volume in liters at the surface

(pressure = 101.3 kPa) is approximately 3% of the mass M of the marine mammal in

kilograms. Therefore, the volume V0 at the surface in cubic meters (note 0.001 m3

/l) is

V0 = 0.001 x 0.03 M. The volume at depth z in meters is determined from the ratio of

pressures. For salt water, this variation can be expressed approximately:

V(z) = V0 x 10 / (z+10). The radius A of an equivalent-volume spherical bubble is thus

A(z) = [V(z) / (4/3)]1/3. Finally, the oscillation period for a spherical bubble is given by

P

A Tosc  97.1 ,

where P = 1.013 x 105

 (1 + z/10) is the absolute pressure in Pascals at depth z.

The calculation for impulse is carried out according to:

(1 ), 0 /

0 0

t t I p t e 

where t is Ts for calculating impulse levels for fishes. For marine mammals, t should

be set to the minimum of Ts and Tosc (Goertner 1982).
68

4.3.6 Root-Mean-Square Levels

The rms sound level metric has gained popularity because it gives the most

representative measure of the average effective amplitude over a transient signal’s

duration. This metric is especially well suited to characterizing sonar pings and signals

such as windowed sine pulses. It also is quite widely applied for estimating impacts of

impulsive airgun noise on marine mammals.

The rms metric is computed as the square root of the mean squared pressure over

the signals “duration,” the definition of which is somewhat ambiguous. Greene (1998)

proposed a method that uses the interval between the times at which 5% and 95% of the

total EFD is received. This method has been augmented (MacGillivray et al. 2002, 2003)

to remove contributions from background noise when the signal to noise ratio is small.

The method is applied by first determining the mean-square background noise amplitude



2

, from which a noise-corrected cumulative energy density function is computed:

  

T

E T p t dt

0

2 2

cum ( ) ( )  .

The cumulative energy density function normally appears as the curve shown in the

lower pane in Figure 4.4. If the background noise level is matched properly, then the

sections of the cumulative EFD function will be constant prior to and after the primary

transient pulse arrivals. The signal duration interval is still determined by the times at

which the function crosses the 5% and 95% total EFD levels. The horizontal dashed lines

in Figure 4.4 represent the 5% and 95% levels, and the vertical lines represent

corresponding start and stop times.

Figure 4.4. Transient pressure signal and corresponding cumulative energy density

function.
69

The rms pressure then is computed from the difference between the 95% and

5% cumulative EFD, divided by the corresponding time difference:

95% 5%

95% 5%

rms

( ) ( )

t t

E t E t

p 

 

4.4 Data Gaps and Recommended Areas of Future Research

The understanding of the physical principles of underwater detonations and of the

propagation of shock and sonic waves in the surrounding medium is in itself quite well

developed and has been thoroughly formalized since decades ago (see Cole 1948). There

are, however, significant gaps in the application of this formal knowledge in a

meaningful way to the real life situations of offshore structures removal. The

containment effect provided by setting the structure-cutting charges below a minimum

prescribed depth of sediment has not been documented for a comprehensive range of

seafloor consistencies, with the result that the extent of the transmission of explosive

energy into the water column may be significantly greater than expected (Nedwell et al.

2001). Much of what is known from experience regarding underwater detonations within

the seafloor comes from rock demolition blasting, which by its very nature is performed

in an altogether different medium from the relatively compliant upper layers of sediment

in which structure-cutting charges are deployed.

The methods for computing sound level metrics are well established. From the

standpoint of providing a reliable physical evaluation of the injury potential to marine life

from an underwater explosion, however, their applicability for gauging

species-dependent impact suffers from a lack of standardization. It is often the case that

damage thresholds such as TTS (recoverable hearing loss) for a particular class of

animals are quoted as a decibel value with no specific indication of the type of metric,

and thus the acoustic signal properties, to which that value pertains. A metric such as

dBht(Species), which may indeed provide the most accurate evaluation of the sub-injury

impact of an acoustic disturbance on a given marine life form, is currently limited in

usefulness and reliability by the lack of a comprehensive database of audiograms based

on measurements performed on a significant number of individuals per species.

A systematic research effort should be undertaken to model numerically the blast

propagation for a range of charge sizes consistent with structure removal practices

through a wide variety of sediment types and for different deployment depths below the

sediment surface. Such modeling should extend to the transfer of energy into the water

column both from the shock wave propagating through the interface, and later decaying

into an acoustic signal, and from the oscillating bubble of detonation gases when

breakout into the water does take place. Experimental validation of model results at

every possible opportunity should form an integral part of the study; this requires

accurate measurement of acoustic levels, and preferably full waveform recording, at one

or more locations in the water columns as well as characterization of the sediment

firmness near the structures being removed, which could be done by penetrometer

probing or similar techniques. Once a reliable modeling approach has been generated
70

and validated, forecasting of the acoustic levels distribution for planned operations would

become possible from the type and location of the charge to be exploded, the depth of the

water column, and the measured properties of the sediment in which the detonation

occurs. In fact, by using a combined blast and acoustic modeling approach, the

longer-range propagation of the sound energy from a cutting charge detonation could be

accurately forecast given knowledge of the bottom topography and the sound velocity

profile in the water. This would alert to possible areas of sound energy concentration that

would be missed by simpler estimators, and would permit the establishment of more

appropriate safe ranges or the iterative revision of the planned blast configuration to

mitigate its effects. In combination with improved estimation of impact thresholds based

on appropriate and standardized sound metrics, such a modeling-based assessment of

each planned decommissioning operation involving explosive removal of underwater

structures would provide the best ability to minimize its repercussions on the marine life

environment.
71 

CHAPTER 5 

AFFECTED ENVIRONMENT 

The following discussion of affected environment considers those components of 

the biological environment that are at the greatest risk of impact from explosive platform 

removal – marine fishes, marine turtles, and marine mammals. In the development of 

this text, emphasis has been placed on the presence and characteristics of species present 

in U.S. waters. Particular emphasis has been placed on listed and/or protected species – 

those protected under ESA and MMPA, respectively. 

5.1 Marine Fishes

 In two OCS Planning Areas, Gulf of Mexico and Pacific, large numbers of fishes 

associate with oil and gas structures. These fishes are briefly characterized below with 

emphasis on federally managed species. 

5.1.1 Gulf of Mexico OCS Region 

 Offshore oil and gas structures of the northern Gulf of Mexico represent a 

significant albeit artificial habitat for pelagic and demersal fishes of the region. Platforms 

provide shelter and settlement sites for numerous species of reef and pelagic fishes. 

Nearly 4,000 platforms and other oil and gas structures on Louisiana’s continental shelf 

represent a significant proportion of available hard bottom habitat for fishes with an 

affinity for structure. 

 Reef and pelagic fishes that associate with oil and gas platforms are broadly 

classified into coastal, offshore, and bluewater assemblages. Coastal platforms are in 

water depths of about 30 m or less and are characterized by variable conditions of limited 

water clarity. The offshore platform assemblage is in water depths ranging from 30 to 

60 m, and bluewater platforms lie along the outer margin of the continental shelf in water 

depths of 60 m or more. Reef fishes such as snappers, groupers, grunts, porgies, 

squirrelfishes, angelfishes, damselfishes, butterflyfishes, and wrasses inhabit offshore and 

bluewater structures. Many of these reef fishes are managed by the Gulf of Mexico 

Fishery Management Council as part of a snapper-grouper (reef fish) management 

complex consisting of 73 species. Red snapper (Lutjanus campechanus) is the most 

important species economically of this group that regularly inhabits offshore oil and gas 

structures (Wilson and Nieland 2001). Reef fishes, including federally managed species, 

known to inhabit oil and gas platforms are listed in Table 5.1. 

 Most fishes associated with platforms in the Gulf of Mexico tend to remain 

relatively near or under the structures (Continental Shelf Associates, Inc. 1982; Gallaway 

and Lewbel 1982; Putt 1982). Stationary hydroacoustic surveys indicate that fish 

densities around platforms sampled with hydroacoustics are highest within a horizontal 

distance of 18 to 50 m from the structure (Stanley and Wilson 1998, 2002). For 
72 

Table 5.1 

Reef Fishes That Associate with Oil and Gas Structures in the Gulf of Mexico 

(Adapted from: Gallaway and Lewbel 1982; Gulf of Mexico Fishery 

Management Council 1998) 

Family Scientific Name Common Name 

Epinephelus nigritus* warsaw grouper 

Epinephelus niveatus* snowy grouper 

Mycteroperca interstitialis* yellowmouth grouper 

Mycteroperca microlepis* gag 

Mycteroperca phenax* scamp 

Serranidae 

Paranthias furcifer creole-fish 

Lutjanus campechanus* red snapper 

Lutjanus griseus* gray snapper 

Lutjanus jocu* dog snapper 

Lutjanus mahogoni* mahogany snapper 

Lutjanus synagris* lane snapper 

Ocyurus chrysurus* yellowtail snapper 

Lutjanidae 

Rhomboplites aurorubens* vermilion snapper 

Haemulidae Haemulon aurolineatum* tomtate 

Sparidae Archosargus 

probatocephalus* sheepshead 

Kyphosidae Kyphosus incisor yellow chub 

Kyphosus sectatrix Bermuda chub 

Ephippidae Chaetodipterus faber Atlantic spadefish 

Chaetodon aya bank butterflyfish 

Chaetodon ocellatus* spotfin butterflyfish 

Chaetodontidae 

Chaetodon sedentarius reef butterflyfish 

Pomacanthidae Holacanthus bermudensis blue angelfish 

Abudefduf saxatilis sergeant major 

Chromis enchrysurus yellowtail reeffish 

Pomacentridae 

Stegastes variabilis cocoa damselfish 

Bodianus pulchellus spotfin hogfish 

Bodianus rufus* Spanish hogfish 

Halichoeres bivittatus slippery dick 

Lachnolaimus maximus* hogfish 

Labridae 

Thalassoma bifasciatum bluehead 

Hypsoblennius hentzi feather blenny

Hypsoblennius invemar tessellated blenny 

Ophioblennius atlanticus redlip blenny 

Parablennius marmoreus seaweed blenny 

Blenniidae 

Scartella cristata molly miller 

Sphyraenidae Sphyraena barracuda great barracuda 

Balistidae Balistes capriscus* gray triggerfish 

* Managed species.
73 

platforms in shelf waters, densities of fishes within the zone of influence of the platform 

were fairly uniform with respect to water depth, whereas in slope waters most of the 

fishes were concentrated above 60 m (Stanley and Wilson 1998). Smaller site-attached 

reef fishes vertically partition the habitat created on platform legs. Blennies utilize as 

living areas empty barnacle shells and interstitial spaces created by the epibiota attached 

to platform legs (Gallaway and Lewbel 1982). Damselfishes, wrasses, and others closely 

associate with legs and cross-members and pilings that support the platforms (Gallaway 

and Lewbel 1982; Boland 2002). Larger reef-associated species such as chubs, snappers, 

triggerfishes, angelfishes, butterflyfishes, spadefishes, and sheepshead are found 

throughout the water column and prefer the cover provided by the structure. 

 The common pelagic fish assemblage found in shelf waters of the Gulf of Mexico 

is usually termed coastal pelagic. Major coastal pelagic families occurring in the Gulf are 

requiem sharks, ladyfish, anchovies, herrings, mackerels, jacks, mullets, bluefish, and 

cobia. Coastal pelagic species traverse shelf waters of the region throughout the year. 

Some species form large schools (e.g., Spanish mackerel), while others travel singly or in 

smaller groups (e.g., cobia). The distribution of most species depends upon water 

column structure, which varies spatially and seasonally. Many coastal pelagic species 

associate with oil and gas structures in the northern Gulf of Mexico. 

 A unique aspect of oil and gas structures when compared with natural hard 

bottom is the vertical component that extends throughout the water column (Stanley and 

Wilson 2002). Adults and early stages of coastal pelagic species are attracted to the 

upper portions of these structures. Jacks (Carangidae) exemplify this phenomenon. 

Large schools of blue runner, crevalle jacks, lookdown, Atlantic bumper, and Atlantic 

moonfish occur in the upper portion of the water column around offshore platforms 

(Gallaway and Lewbel 1982). Other pelagic species including bluefish, king and Spanish 

mackerels, little tunny, and other tunas also associate with platforms. Coastal pelagic 

fishes including federally managed species, commonly found around platforms, are given 

in Table 5.2. 

 Epipelagic or highly migratory species such as billfishes, dolphin, tunas, and 

wahoo are found around blue water platforms. Little is known about the spatial 

relationships that these species have with offshore structures, but these structures seem to 

have a fish attraction device (FAD) effect (Edwards et al. 2002). Highly migratory 

species including sharks also are managed by the NMFS. 

5.1.2 Pacific OCS Region

 Managed fishes in the Pacific OCS region that associate with offshore oil and gas 

structures are classified as groundfishes. The groundfish management unit includes over 

70 species, most of which are rockfishes (Scorpaenidae). 
74 

Table 5.2 

Pelagic Species That Associate with Oil and Gas Structures in the Gulf of Mexico 

(Adapted from: Gallaway and Lewbel 1982; Gulf of Mexico Fishery 

Management Council 1998) 

Family Scientific Name Common Name 

Pomatomidae Pomatomus saltatrix bluefish 

Rachycentridae Rachycentron canadum* cobia 

Caranx crysos blue runner 

Caranx hippos crevalle jack 

Caranx latus horse-eye jack 

Chloroscombrus chrysurus Atlantic bumper 

Decapterus punctatus round scad 

Elagatis bipinnulata rainbow runner 

Selene setapinnis Atlantic moonfish 

Selene vomer lookdown 

Seriola dumerili greater amberjack 

Seriola fasciata lesser amberjack 

Carangidae 

Seriola rivoliana almaco jack 

Coryphaenidae Coryphaena hippurus* dolphin 

Istiophoridae Istiophorus platypterus* sailfish 

Makaira nigricans* blue marlin 

Acanthocybium solanderi wahoo 

Euthynnus alletteratus* little tunny 

Katsuwonus pelamis* skipjack tuna 

Scomber japonicus chub mackerel 

Scomberomorus cavalla* king mackerel 

Scomberomorus maculatus* Spanish mackerel 

Thunnus albacares* yellowfin tuna 

Scombridae 

Thunnus atlanticus* blackfin tuna 

* Managed species. 

 Assemblages of fishes associated with platforms in the Santa Barbara Channel 

have been recently studied by Love et al. (2000). These platforms lie in water depths 

ranging from 49 to 224 m. Assemblages are composed of 15 families, with rockfishes 

(Sebastes spp.) contributing most of the species, followed by greenlings (hexagrammids) 

and surf perches (embiotocids). Species and families associated with platforms in the 

Santa Barbara Channel are provided in Table 5.3. 
75 

Table 5.3 

Fish Species Associated with Oil and Gas Platforms in Santa Barbara Channel 

(From: Love et al. 2001) 

Family Scientific Name Common Name 

Sebastes aleutianus* rougheye rockfish 

Sebastes atrovirens* kelp rockfish 

Sebastes auriculatus* brown rockfish 

Sebastes babcocki* redbanded rockfish 

Sebastes carnatus* gopher rockfish 

Sebastes caurinus* copper rockfish 

Sebastes chlorostictus* greenspotted rockfish 

Sebastes constellatus starry rockfish 

Sebastes dallii* calico rockfish 

Sebastes elongates* greenstriped rockfish 

Sebastes ensifer swordspine rockfish 

Sebastes entomelas* widow rockfish 

Sebastes flavidus* yellowtail rockfish 

Sebastes goodei* chilipepper 

Sebastes helvomaculatus* rosethorn rockfish 

Sebastes hopkinsi* squarespot rockfish 

Sebastes jordani* shortbelly rockfish 

Sebastes levis* cowcod 

Sebastes macdonaldi* Mexican rockfish 

Sebastes miniatus* vermilion rockfish 

Sebastes moseri whitespeckled rockfish 

Sebastes mystinus* blue rockfish 

Sebastes paucispinis* bocaccio 

Sebastes pinniger* canary rockfish 

Sebastes rosaceus* rosy rockfish 

Sebastes rosenblatti* greenblotched rockfish 

Sebastes ruberrimus* yelloweye rockfish 

Sebastes rubrivinctus* flag rockfish 

Sebastes rufus* bank rockfish 

Sebastes saxicola* stripetail rockfish 

Sebastes semicinctus halfbanded rockfish 

Sebastes serriceps* tree rockfish 

Sebastes simulator pinkrose rockfish 

Sebastes umbrosus* honeycomb rockfish 

Sebastes wilsoni pygmy rockfish 

Sebastes zacentrus* sharpchin rockfish 

Sebastomus Sebastomus group 

Scorpaenidae 

Scorpaena guttata spotted scorpionfish 
Table 5.3. Fish Species Associated with Oil and Gas Platforms in Santa Barbara Channel 

(From: Love et al. 2001). (continued). 

76 

Family Scientific Name Common Name 

Hexagrammos decagrammos* kelp greenling 

Ophiodon elongatus* lingcod 

Oxylebius pictus painted greenling 

Zaniolepis sp. combfish 

Zaniolepis frenata unid. shortspine combfish 

Hexagrammidae 

Zaniolepis latipinnis longspine combfish 

Pomacentridae Chromis punctipinnis blacksmith 

Hypsypops rubicundus garibaldi 

Damalichthys vacca pile perch 

Embiotocidae sp. unid. surfperch 

Phanerodon atripes sharpnose surfperch 

Rhacocilus toxotes rubberlip surfperch 

Embiotocidae 

Zalembius rosaceus pink surfperch 

Merlucciidae Merluccius productus* Pacific hake 

Flatfish Microstomus pacificus* Dover sole 

Gobiidae Coryphopterus nicholsi blackeye goby 

Cottidae Scorpaenichthys marmoratus cabezon 

Kyphosidae Girella nigricans opaleye 

Medialuna californiensis halfmoon 

Serranidae Paralabrax clathratus kelp bass 

Labridae Semicossyphus pulcher sheephead 

Anarrhichadidae Anarrhichthys ocellatus wolf-eel 

Bathymasteridae Bathymasteridae sp. ronquils 

Chimaeridae Hydrolagus colliei* ratfish 

Clupeidae Sardinops sagax Pacific sardine 

* Managed species.

 Fishes from 15 families and over 60 species colonize platforms in Santa Barbara 

Channel (Love et al. 1994, 1999, 2000, 2001). Platform assemblages are dominated in 

terms of biomass and numbers by rockfishes (Sebastes spp.). Twenty-nine species 

inhabit bottom and mid-waters around the platforms. The most common species in 

bottom waters around the platforms are halfbanded rockfish (Sebastes semicinctus), 

greenspotted rockfish (Sebastes chlorostictus), copper rockfish (Sebastes caurinus), and 

vermilion rockfish (Sebastes miniatus). In mid-water, widow rockfish (Sebastes 

entomelas), juvenile rockfishes (Sebastes spp.), and blacksmith (Chromis punctipinnis) 

were most common. Rockfish juveniles (less than 2 years old) were most numerous in 

mid-water, where rockfish larger than 18 cm were rarely observed. In bottom waters, 

larger adults and subadults were abundant. The bottom area of the platforms consistently 

supported more species than mid-water areas likely because of greater habitat complexity 

in bottom waters. 
77 

5.1.3 Alaska OCS Region 

In the Alaska OCS, there is no information on platform-associated fishes for the 

primary offshore oil and gas field – Cook Inlet. There are platforms and structures in the 

Beaufort Sea, but these are built upon large gravel causeways or berms and will not be 

removed with explosives. Although the platform fauna of the Alaska region have not 

been characterized as they have been in the Gulf of Mexico and Santa Barbara Channel, 

Cook Inlet is a much smaller water body that supports important fisheries, particularly 

salmon and Pacific herring. Economically important species managed by the North 

Pacific Fishery Management Council are Pacific herring, salmon, and groundfishes 

(Table 5.4). Ichthyofaunal surveys conducted in the Gulf of Alaska and Cook Inlet 

revealed the spatial and temporal dynamics of fishes inhabiting the area (Blackburn et al. 

1979; Mecklenburg et al. 2002; Mueter and Norcross 2002). 

Spatial and temporal fluctuations in size composition and distribution of pelagic 

and demersal species is a common pattern in Cook Inlet. Most of the common species 

move out of nearshore areas in the late summer and fall and remain offshore until spring. 

Small pelagic species including Pacific herring, capelin, long fin, and surf smelts are 

among those species that migrate out of the shallows in fall. These species are an 

important food source for larger predators such as salmon, sea birds, and marine 

mammals. 

Table 5.4 

Managed Fish Species Found in Lower Cook Inlet, Alaska (From: North Pacific Fishery 

Management Council 2002) 

Family Scientific Name Common Name 

Clupeidae Clupea pallasii Pacific herring 

Oncorhynchus gorbuscha pink salmon 

Oncorhynchus keta chum salmon 

Oncorhynchus kisutch coho salmon 

Oncorhynchus nerka sockeye salmon 

Salmonidae 

Oncorhynchus tshawytscha Chinook salmon 

Gadidae Gadus macrocephalus Pacific cod 

Theragra chalcogramma walleye pollock 

Sebastolobus altivelis longspine thornyhead 

Sebastes caurinus copper rockfish 

Sebastes helvomaculatus rosethorn rockfish 

Sebastes maliger quillback rockfish 

Sebastes nebulosus China rockfish 

Sebastes nigrocinctus tiger rockfish 

Sebastes pinniger canary rockfish 

Scorpaenidae 

Sebastes ruberrimus yelloweye rockfish 

Anoplopomatidae Anoplopoma fimbria sablefish 

Hexagrammidae Pleurogrammus monopterygius Atka mackerel 
Table 5.4. Managed Fish Species Found in Lower Cook Inlet, Alaska (From: North 

Pacific Fishery Management Council 2002). (continued). 

78 

Family Scientific Name Common Name 

Atheresthes stomias arrowtooth flounder 

Hippoglossus stenolepis Pacific halibut 

Hippoglossoides elassodon flathead sole 

Hippoglossoides robustus Bering flounder 

Psettichthys melanostictus sand sole 

Isopsetta isolepis butter sole 

Lepidopsetta bilineata southern rock sole 

Lepidopsetta polyxystra northern rock sole 

Limanda aspera yellowfin sole 

Limanda proboscidea longhead dab 

Parophrys vetulus English sole 

Platichthys stellatus starry flounder 

Pleuronectidae 

Pleuronectes quadrituberculatus Alaska plaice 

The salmonids are the primary large pelagic fishes in the area. These species 

enter the shallows in spring and migrate up adjacent rivers during summer months to 

spawn. Young salmon migrate downstream during summer months to rich estuarine 

feeding grounds. 

Demersal species found in Cook Inlet are cod, flatfishes, sculpins, greenlings, and 

rockfishes. These species will move into shallower water during spring and summer. 

Rockfishes, greenlings, sculpins, and rock sole prefer structured rocky habitats. Juvenile 

salmon, herring, and sand lance will associate with rocky areas during summer months. 

Pacific halibut are found on rubble or shell hash bottom types. Other flatfishes are most 

common on soft sedimentary substrates. 

5.2 Marine Turtles 

5.2.1 Marine Turtles of North America 

Currently, all marine turtles are placed within one order, Chelonii, and 

two families, Cheloniidae and Dermochelyidae. Cheloniids possess a fused, hard shell 

that is covered with horny scutes of variable number. Dermochelyids possess a shell 

characterized by extreme reduction of bones in both carapace and plastron (upper and 

lower shell, respectively), whose epithecal layer consists of a mosaic of thousands of 

small, polygonal bones supported by a thick matrix of oil-laden, cartilagenous dermal 

tissue (Marquez 1990). 

Marine turtle sexes are dimorphic in both families. Female marine turtles 

typically come ashore on sandy beach and dune habitats only to nest, while males remain 

permanently aquatic (Wyneken 1997). All species exhibit stereotyped nesting behavior, 
79 

lay relatively large numbers of eggs several times during the reproductive period, and 

demonstrate relatively strong attachment to a particular location for nesting (with 

inter- and intraspecific variability) (Miller 1997). 

 Cheloniid marine turtles have a pantropical distribution, with periodic migrations 

into temperate habitats for opportunistic feeding during warm seasons (Marquez 1990). 

In North American waters, there are six species within four genera: Caretta, Chelonia, 

Eretmochelys, and Lepidochelys. The family Dermochelyidae is represented by 

one genus, Dermochelys. Brief descriptions of marine turtle species that may occur 

within North American waters are found below. 

Loggerhead Turtle 

 The loggerhead turtle, Caretta caretta, is the largest cheloniid turtle, with a 

carapace length of approximately 81 to 105 cm. Mature individuals weigh about 135 kg, 

though some individuals may attain much larger sizes (Marquez 1990; Ernst et al. 1994). 

Loggerhead turtles are widely distributed in coastal tropical and subtropical waters, and 

are also commonly found in temperate waters, moving within the bounds of warm 

currents (e.g., Gulf Stream, North Equatorial Current, Kuroshio Current, and California 

Current in the northern hemisphere). Loggerhead turtles are widely distributed 

throughout their range, with respect to water depth. They are found in open ocean 

habitats, waters of the continental shelf, and nearshore and coastal areas such as bays, 

lagoons, salt marshes, creeks, and the mouths of large rivers (Ernst et al. 1994). The 

loggerhead turtle is omnivorous, though benthic invertebrates appear to be the most 

important constituents of their diet. 

Though not commercially exploited for its flesh or shell, Caretta nesting 

populations are declining as a result of incidental catch in shrimp trawls in both southern 

Queensland, Australia and in the U.S. north of Cape Canaveral. The larger populations in 

Florida south of Cape Canaveral and the relatively small population off South Africa are 

increasing (Pritchard 1997). Caretta is currently listed as threatened in U.S. waters under 

ESA. 

Green Turtle and Black Turtle 

The green turtle, Chelonia mydas, ranges from approximately 81 to 112 cm in 

carapace length. It is widely distributed in tropical and subtropical waters, and migrates 

across the open ocean to feeding habitats in shallow water supporting an abundance of 

submerged vegetation (Ernst et al. 1994). 

The black turtle, Chelonia agassizii, is approximately 70 to 80 cm in carapace 

length (Marquez 1990). It inhabits primarily coastal waters along the west coast of 

America, primarily between Baja California to southern Peru. This species is not 

commonly observed in the open ocean environment. 
80 

Chelonia, in adulthood, are primarily herbivorous. Food items include algae, red 

mangrove (Rhizophora spp.) roots and leaves, and seagrasses. Feeding behavior in early 

stages (hatchling to juvenile) is assumed to be carnivorous (Marquez 1990; Ernst et al. 

1994). 

 The green turtle has long been harvested for both meat and eggs under increasing 

demand for subsistence and local markets by indigenous people. However, local colonies 

appear to be on the increase, and on the whole the species does not appear to be faced 

with imminent extinction (Pritchard 1997). Florida nesting populations of green turtles 

are currently listed as endangered under the ESA, while other nesting populations in 

U.S. waters are listed as threatened. The black turtle is captured in uncontrolled numbers 

within areas of their range. Consequently, the outlook for this species is, in the long run, 

uncertain. 

Hawksbill Turtle 

 The average carapace length in adult female hawksbill turtles (Eretmochelys 

imbricata) ranges from approximately 50 to 114 cm. This species is predominantly 

tropical and distributed throughout the central Atlantic and Pacific regions of America. It 

is characteristically an inhabitant of tropical, exposed hard bottom habitats, including 

coral reefs. It also may be found in shallow coastal areas such as mangrove-bordered 

embayments, estuarine habitats, mud-bottomed lagoons, and creeks and passes (Ernst 

et al. 1994). Capture/recapture data for subadult hawksbills suggest that at least part of 

the population demonstrates residential, or non-migratory, behavior, though these adults 

may perform migratory movements during the breeding season. The hawkbill turtle is 

principally carnivorous, and its diet consists primarily of sponges. In addition, it is 

known to eat coelenterates, ascideans, bryozoans, echinoids, mollusks, barnacles, 

crustaceans, algae, seagrasses, and mangrove (Rhizophora). 

Intense commercial trade of hawksbill turtle shell (or “carey”) has led to 

widespread concerns that this species is being seriously overexploited (Pritchard 1997; 

Fleming 2001). The future of this species has been labeled “indeterminate.” The 

hawksbill turtle is currently listed as endangered under ESA (Pritchard 1997). 

Kemp's Ridley and Pacific (Olive) Ridley 

The Kemp's ridley, Lepidochelys kempii, ranges from approximately 52 to 75 cm 

in carapace length. Adult Kemp's ridleys usually occur only in the Gulf of Mexico, 

though juveniles and subadults may range between tropical and temperate waters of the 

northwestern Atlantic Ocean and occasionally Europe and Africa. In the Gulf of Mexico, 

Kemp's ridleys usually inhabit sandy and muddy bottom habitats, including bays, coastal 

lagoons, and river mouths. 

The Pacific (or olive) ridley, Lepidochelys olivacea, is similar in size, but has a 

slightly deeper body than the Kemp's ridley (Marquez 1990; Ernst et al. 1994). It is 

pantropical, though occurs primarily within the northern hemisphere, with the 20°C 
81 

isotherms as its distributional boundaries. Adults are most frequently observed in 

shallow waters, though there are observations of them feeding in deeper waters (i.e., to 

200 m) (Marquez 1990; Ernst et al. 1994). 

Lepidochelys are carnivorous throughout their life cycles, feeding principally on 

crabs, shrimps, mollusks, echinoids, jellyfishes, and fishes (Marquez 1990; Ernst et al. 

1994). 

Lepidochelys are listed as endangered under ESA. The Kemp's ridley is 

considered the rarest extant marine turtle species, although there are current apparent 

population increases (Pritchard 1997). The Pacific ridley, in contrast, remains the most 

numerous species of marine turtle. Nesting sites are reasonably protected, though 

incidental take by trawlers is significant in certain areas (Pritchard 1997). 

Leatherback Turtle 

The leatherback turtle, Dermochelys coriacea, is among the world's largest living 

reptiles. Carapace lengths range from approximately 130 to 260 cm. They are easily 

recognized by their large size and leathery, keeled shell. The leatherback turtle possesses 

unique abilities when compared to other marine turtles. They maintain limited 

endothermic (i.e., warm blooded) ability, due to the insulative and thermogenic qualities 

of their thick layers of oil-saturated, subepidermal fat; large, insulating body mass; and a 

countercurrent heat exchange system of arteries and veins in their limbs (Ernst et al. 

1994; Ruckdeschel et al. 2000). In addition, the leatherback turtle is physiologically 

capable of repeatedly diving to and foraging at depths of over 1,000 m. 

Though mainly tropical nesters, the leatherback turtle forages in all waters 

poleward to the Arctic and Antarctic (Marquez 1990). They feed extensively on pelagic, 

gelatinous, and other soft-bodied invertebrates, primarily jellyfishes and salps. Data 

suggest their distribution is strongly influenced by mesoscale and local oceanographic 

features that concentrate their prey items. They forage within deep scattering layers of 

the open ocean, but are also commonly seen relatively close to shore because of their 

prey distribution (Ruckdeschel et al. 2000). 

Adult leatherback turtles are not exploited commercially, though subsistence take 

of eggs, and sometimes of nesting adults, has been intense. Atlantic colonies, on the 

whole, appear to be reasonably secure and in some cases increasing. However, serious 

declines have been documented in Pacific Mexico and Costa Rica (Pritchard 1997). The 

leatherback turtle is currently listed as endangered in U.S. waters under ESA. 

5.2.2 Distributions of Marine Turtles and Their Association with Offshore Oil and 

Gas Structures 

There are differential distributions among the various sea turtle life stages – 

hatchling, juvenile, and adult (Marquez 1990; Hirth 1997; Musick and Limpus 1997). 

For example, in the Gulf of Mexico, hatchling turtles are typically pelagic and may be 

found within zones of water mass convergence and/or sargassum rafts, which are rich in 
82 

prey and provide shelter (NMFS and USFWS 1991; Hirth 1997). These hatchlings may 

have originated from nesting sites along Gulf of Mexico shores or adjacent areas such as 

the Caribbean Sea. Juvenile turtles may actively move across the open Gulf to shallow 

water developmental habitats and adult foraging habitats, respectively. Adult foraging 

habitats may be, in some species or populations, geographically distinct from their 

juvenile developmental habitats (Musick and Limpus 1997). All marine turtles migrate, 

at least short distances, from foraging areas to mating areas. After mating, males, which 

remain permanently aquatic, return to foraging areas, and females move to nesting areas. 

After a reproductive period of up to several months, females return to foraging areas 

(Miller 1997). 

Most marine turtle species commonly inhabit areas characterized by topographic 

relief such as exposed rock features and reefs (Carr 1954; Booth and Peters 1972; 

Stoneburner 1982; Witzell 1982). Offshore oil and gas structures also provide 

topographic relief in areas and have been shown to attract marine turtles (Fuller and 

Tappan 1986; Rosman et al. 1987; Gitschlag and Renaud 1989; Lohoefener et al. 1989; 

Gitschlag 1990; Lohoefener et al. 1990; Gitschlag and Herczeg 1994). Turtles may use 

offshore platforms as places to feed and rest, and as a refuge from predators and strong 

currents (NRC 1996). 

Observational data from the Gulf of Mexico indicate that the loggerhead turtle is 

the most common marine turtle species sighted near offshore oil and gas structures, 

though green turtles, hawksbill turtles, Kemp's ridley, and leatherback turtles also have 

been sighted. These data also indicate that certain individual loggerheads may reside at 

specific offshore structures for extended periods of time (Rosman et al. 1987; Gitschlag 

and Renaud 1989). 

5.2.3 Distributions of Marine Turtle Species Within MMS OCS Planning Areas 

The distributions of marine turtle species within MMS OCS Planning Areas 

where there are offshore oil and gas structures (Gulf of Mexico, Pacific, and Alaska OCS 

Planning Areas) are listed in Table 5.5. 

Table 5.5 

Marine Turtle Species Within Minerals Management Service Gulf of Mexico (GOM), 

Pacific, and Alaska Outer Continental Shelf (OCS) Planning Areas (Derived from 

Pritchard 1990) 

Common Name Genus/Species GOM OCS Pacific OCS Alaska OCS 

Loggerhead turtle Caretta caretta X1 X2 X2

Green turtle Chelonia mydas X1 

Black turtle Chelonia agassizii X2 

Hawksbill turtle Eretmochelys imbricata X2 

Kemp's ridley Lepidochelys kempii X1 

Pacific (olive) ridley Lepidochelys olivacea X1 

Leatherback turtle Dermochelys coriacea X1 X1 X1

1

 Normal distributional range. 

2

 Occurrence seasonal or extralimital. 
83 

5.3 Marine Mammals 

The following summary of marine mammals has been organized by OCS region – 

Gulf of Mexico, Pacific, and Alaska. Marine mammal data have been compiled and 

summarized based on both historical and recent aerial and/or shipboard surveys. Focus 

has been placed on those areas within each region where oil and gas platforms or other 

OCS facilities have been placed and will require removal. 

All marine mammals are protected by federal law (MMPA), which affords 

individuals and populations from mortality, injury, or harassment. Under MMPA, a 

species may be designated as a depleted or strategic stock. A stock is depleted when 

declines in numbers result in the population falling below its optimal sustainable 

population. A stock is considered strategic when it is presumed that human activities 

may be having a deleterious effect on the population and that the population may not be 

sustainable. In addition, individual species may also be designated as threatened or 

endangered under the ESA. A stock may be classified as threatened or endangered, 

depleted, and strategic simultaneously. Systematic conventions follow those outlined by 

Rice (1998). 

5.3.1 Gulf of Mexico OCS Region 

Toothed whales are the by far the most abundant marine mammal in the Gulf of 

Mexico (Table 5.6). Seals and sea lions are absent, and Bryde’s whale is the only 

mysticete that is seen with any regularity (Davis et al. 2000; Würsig et al. 2000). 

Sixteen species are routinely sighted in the Gulf of Mexico, and most are year-round 

residents (Davis et al. 2000). Manatees are typically sighted off the coast of Florida but 

also have been observed off the coast of Texas, Louisiana, and/or Mississippi virtually 

every summer since 1970 (Würsig et al. 2000). As noted previously, it is extremely 

unlikely that manatees will be adversely affected by explosive platform removal activities 

over the continental shelf or slope.

Bottlenose dolphins and Atlantic spotted dolphins are by far the dominant species 

of the continental shelf and shelf edge. Bottlenose dolphins can also range onto the 

continental slope in the northeast Gulf. The most abundant species in deepwater are 

Stenella spp. dolphins. Bryde’s whales have been found in the northeastern Gulf along 

the 100-m contour. 

The deepwater species appear to have geographical preferences (Davis et al. 

2000; Würsig et al. 2000): 

• Pygmy and dwarf sperm whales, killer whales, pantropical spotted dolphins, 

striped dolphins, and Risso’s dolphins range throughout the northern Gulf; 

however, pantropical spotted and striped dolphins may be rare in the 

northwest Gulf. Killer whales tend to concentrate near the Mississippi delta. 
Table 5.6 

Abundance, Protective Status (Under the Endangered Species Act), Habitat Characteristics, Group Size, and Di

Marine Mammals That are Known to (or May) Occur in the Northern Gulf of Mexico. The Number of Xs Ind

Occurrence of the Species in the Continental Shelf, Slope, and Offshore Area (Increasing Number of Xs Indi

Occurrence) 

Continental Shelf 

Species Occurrence1 Abundance2 Density3 [#/100 km2](CV) g(0)4 ESA Status5 Habitat Nearshore Offshore Slope Offshore Waters S

OdontocetesSperm whale (Physeter macrocephalus) 

Common 530 0.111 (0.41) 0.87 E Slope and deep sea X X A

Pygmy sperm whale (Kogia breviceps) 

Common 733a 0.968 (0.47) 0.19 Slope and deep sea XX X A

Dwarf sperm whale (Kogia sima) 

Common 733a 0.968 (0.47) 0.19 Shelf edge and slope X XX X A

Cuvier’s beaked whale (Ziphius cavirostris) 

Rare 159 0.308 (0.76) 0.13 Pelagic XX X A

Sowerby's beaked whale (Mesoplodon bidens) 

Extralimital 150b N.A. 0.26 Pelagic XX X 

Gervais' beaked whale (Mesoplodon europaeus) 

Uncommon 150b N.A. 0.26 Pelagic XX X 

Blainville’s beaked whale (Mesoplodon densirostris) 

Rare 150b N.A. 0.26 Pelagic XX X 

Rough-toothed dolphin (Steno bredanensis) 

Common 852 0.114 (0.83) 1 Mostly pelagic X X A

Bottlenose dolphin (Tursiops truncatus) 

Common 5,618c 1.358 (0.47) 0.561 Shelf waters XXX XXX X X A

Pantropical spotted dolphin (Stenella attenuata) 

Common 46,625 11.687 (0.24) 1 Pelagic X XX XXX A

Atlantic spotted dolphin (Stenella frontalis) 

Common 3,213 0.235 (0.76) 0.561 Shelf waters XX X A

Spinner dolphin (Stenella longirostris) 

Common 11,251 2.820 (0.60) 1 Coastal and pelagic X X X A

Clymene dolphin (Stenella clymene) 

Common 10,093 2.530 (0.60) 1 Pelagic X X A

Striped dolphin (Stenella coeruleoalba) 

Common 4,858 1.098 (0.72) 1 Pelagic X X A

Short-beaked common dolphin (Delphinus delphis) 

Possible N.A. N.A. 0.561 Continental shelf and 

pelagic 

X X X X 
Table 5.6. Abundance, Protective Status (Under the Endangered Species Act), Habitat Characteristics, Group Si

Characteristics of Marine Mammals That are Known to (or May) Occur in the Northern Gulf of Mexi

Xs Indicates the Relative Occurrence of the Species in the Continental Shelf, Slope, and Offshore Are

Number of Xs Indicate an Increase in Occurrence) (continued). 

Continental Shelf 

Species Occurrence1 Abundance2 Density3 [#/100 km2](CV) g(0)4 ESA Status5 Habitat Nearshore Offshore Slope Offshore Waters S

Long-beaked common dolphin 

(Delphinus capensis) 

Possible N.A. N.A. 0.561 Coastal waters X X 

Fraser’s dolphin (Lagenodelphis hosei) 

Common 127 0.067 (0.94) 1 Depth >1,000 m X XX 

Risso’s dolphin (Grampus griseus) 

Common 3,040 1.358 (0.40) 0.561 Depth 400-1,000 m X XX X A

Melon-headed whale (Peponocephala electra) 

Common 3,965 0.435 (0.94) 1 Pelagic X XX XX 

Pygmy killer whale (Feresa attenuata) 

Uncommon 518 0.078 (0.94) 0.561 Deep pelagic X X A

False killer whale (Pseudorca crassidens) 

Uncommon 817 0.365 (0.94) 0.561 Pelagic X X 

Killer whale (Orcinus orca) Uncommon 277 0.030 (0.83) 0.561 Coastal X X X X Short-finned pilot whale (Globicephala macrorhynchus) 

Common 1,471 0.369 (0.65) 1 Mostly pelagic X X A

Long-finned pilot whale (Globicephala melas) 

Possible N.A. N.A. 1 Mostly pelagic X X 

MysticetesNorth Atlantic right whale (Balaena glacialisd) 

Extralimital N.A. N.A. 0.902 E Coastal and shelf 

waters 

XX X 

Humpback whale (Megaptera novaeangliae) 

Rare N.A. N.A. 0.902 E Nearshore and banks XX XX X 

Minke whale (Balaenoptera acutorostrata) 

Rare N.A. N.A. 0.84 Continental shelf, 

coastal waters 

X X 

Bryde’s whale (Balaenoptera edeni) 

Uncommon 35 0.006 (0.94) 0.902 All XX X X X A

Sei whale (Balaenoptera borealis) 

Rare N.A. N.A. 0.902 E All X X X X 

Fin whale (Balaenoptera physalus) 

Rare N.A. N.A. 0.902 E All X X X X 

Blue whale (Balaenoptera musculus) 

Extralimital N.A. N.A. 0.902 E All X X X X 
Table 5.6. Abundance, Protective Status (Under the Endangered Species Act), Habitat Characteristics, Group Si

Characteristics of Marine Mammals That are Known to (or May) Occur in the Northern Gulf of Mexi

Xs Indicates the Relative Occurrence of the Species in the Continental Shelf, Slope, and Offshore Are

Number of Xs Indicate an Increase in Occurrence) (continued). 

Continental Shelf 

Species Occurrence1 Abundance2 Density3 [#/100 km2](CV) g(0)4 ESA Status5 Habitat Nearshore Offshore Slope Offshore Waters S

SirenianWest Indian manatee (Trichechus manatus) 

Common 1,856 N.A. E Very near shore X A

1 From Würsig et al. (2000).

2 Abundance estimate from Davis et al. (2000) and Waring et al. (2001, 2002).

3 Densities based on the 1996/97 GulfCet II surveys for the northern Gulf (Davis et al. 2000), cor rected for f(0) and g(0).

4 g(0) is the probability of an animal being at the surface at any given time. g(0) depends on group size and is given for average group sizes seen in the Gulf of Mexico (

sizes >16.

5 E = endangered.

6 The range and (average) group size are shown.a Estimate for dwarf and pygmy sperm whales.b Estimate for all Mesoplodon spp.c Gulf of Mexico continental shelf edge and continental slope stock. d Eubalaena [=Balaena] per Rice (1998). 
87 

• False killer whales, pygmy killer whales, Fraser’s dolphin, and beaked whales 

range throughout the northern Gulf, but are rare. 

• Sperm whales generally occur along the lower continental shelf throughout 

the northern Gulf and may congregate at the 1,000-m isobath near the 

Mississippi River delta. 

• Spinner dolphins occur in the north-central and northeast Gulf of Mexico. 

• Short-finned pilot whales and melon-headed whales occur in the north-central 

and northwest Gulf. 

• The distribution of rough toothed dolphins and clymene dolphins may vary 

from year to year, occurring either in the northeast or northwest Gulf. 

There have been recent surveys of marine mammals in the Gulf of Mexico 

(Davis et al. 2000), and Würsig et al. (2000) have summarized current knowledge on the 

subject. Some of the data needed to plan monitoring and mitigation measures are 

summarized in Table 5.6. Caution needs to be used in interpreting and using these kinds 

of data. Bottlenose dolphins and Atlantic spotted dolphins appear to be the most 

common species on the continental shelf. However, environmental conditions could 

cause a normally pelagic offshore species to venture onto the continental shelf while 

following an abundance of potential food. 

5.3.2 Pacific OCS Region

Numerous marine mammal species are resident or transitory throughout the 

Pacific OCS Region. This section deals only with marine mammals found in those areas 

where offshore platforms occur – offshore southern California (portions of the Southern 

California Bight – San Pedro shelf, Santa Barbara Channel; see Dailey et al. 1993) and 

the southern portions of the Santa Maria Basin (southern central California offshore, 

offshore Point Conception – Point Arguello). The marine mammals of California are 

described by Orr and Helm (1989) and Perrin et al. (2002). General species 

characterization data for seals and sea lions were derived from Reidman (1990). Survey 

data on marine mammals off the U.S. west coast, including offshore California, are 

provided in Barlow (1994, 1997). 

Cetaceans

Thirty-three species of cetaceans may occur in the Southern California Bight 

(Koski et al. 1998; Table 5.7). These include 25 species of toothed whales and eight 

species of baleen whales. Many species are migratory or occur only seasonally in the 

area, while others are year-round residents. Common species include Dall’s porpoise 

(Phocoenoides dalli), Pacific white-sided dolphin (Lagenorhynchus obliquidens), Risso’s 

dolphin (Grampus griseus), short-beaked common dolphin (Delphinus capensis), 

northern right whale dolphin (Lissodelphis borealis), and gray whale. Other species 

occur in relatively moderate or small numbers or are only occasionally sighted. 

In the waters of the Southern California Bight, the sperm, northern right, 

humpback, blue, fin, and Sei whales are federally listed as endangered and protected 
Table 5.7 

Common and Scientific Names, Abundance, Status, and Seasonal Occurrence of Cetaceans That May Occu

California Bight (Adapted from: Department of the Navy 2002) 

Species Abundance Status 

Odontocetes: Porpoises (Family Phocoenidae)Harbor porpoise Rare Protected  Phocoena phocoena Dall's porpoise Common Protected Ye Phocoenoides dalli Dolphins (Family Delphinidae)Pacific white-sided dolphin Common Protected Ye Lagenorhynchus obliquidens Risso's dolphin Common Protected Ye Grampus griseus Bottlenose dolphin Rare Protected Ye Tursiops truncatus Short-beaked common dolphin Common/Abundant Protected Ye Delphinus capensis Long-beaked common dolphin Uncommon Protected Ye Delphinus capensis Northern right whale dolphin Common Protected  Lissodelphis borealis Short-finned pilot whale Uncommon Strategic Ye Globicephala macrorhynchus Striped dolphin Occasional Protected  Stenella longirostris Spinner dolphin Rare Protected  Stenella longirostrisSpotted dolphin Rare Protected  Stenella attenuata 
Table 5.7. Common and Scientific Names, Abundance, Status, and Seasonal Occurrence of Cetaceans That May 

Southern California Bight (Adapted from: Department of the Navy 2002) (continued). 

Species Abundance Status 

Rough-toothed dolphin Rare Protected  Steno bredanensis Killer whale Uncommon Protected Ye Orcinus orca False killer whale Rare Protected  Pseudorca crassidens Beaked whales (Family Ziphiidae) Cuvier's beaked whale Uncommon Protected  Ziphius cavirostris Baird's beaked whale Rare Protected Lat Berardius bairdii Blainville's beaked whale Rare Protected  Mesoplodon densirostris Hector's beaked whale Rare Protected  M. hectori Stejneger's beaked whale Rare Protected  M. stejnegeri Hubb's beaked whale Rare Protected  M. carlhubbsi Gingko-toothed whale Rare Protected  M. ginkgodens Sperm whale (Family Physeteridae) Sperm whale Uncommon Endangered, Depleted, Strategic  Physeter macrocephalus Pygmy sperm whales (Family Kogiidae) Pygmy sperm whale Rare Protected Ye Kogia breviceps Dwarf sperm whale Possible visitor Protected  Kogia simus 
Table 5.7. Common and Scientific Names, Abundance, Status, and Seasonal Occurrence of Cetaceans That May 

Southern California Bight (Adapted from: Department of the Navy 2002) (continued). 

Species Abundance Status 

Mysticetes: Right whales (Family Balaenidae) Northern right whale Rare Endangered  Eubalaena (=Balaena) glacialis Gray whale (Family Eschrichtiidae) Gray whale Common Protected Mig Eschrichtius robustus Rorquals (Family Balaenopteridae) Humpback whale Uncommon Endangered, Depleted, Strategic M Megaptera novaeangliae Blue whale Uncommon Endangered, Depleted, Strategic  Balaenoptera musculus Fin whale Uncommon Endangered, Depleted, Strategic Ye B. physalus Sei whale Rare Endangered, Depleted, Strategic  B. borealis Bryde's whale Rare Protected  B. edeni Minke whale Uncommon Protected  B. acutorostrata 
91 

under the ESA. Population trends evident among the endangered cetaceans occurring in 

the waters off California differ among species. From 1980 onwards, sperm whale 

numbers have been variable but no trend has been evident (Carretta et al. 2002). Sperm 

whales are usually found in deeper waters seaward of the continental slope during fall 

and winter. 

Humpback whale numbers have apparently increased in the waters off California 

since 1980 at approximately 8% per year (Carretta et al. 2002). The humpback 

population estimates for the entire North Pacific have also increased from an estimated 

1,200 animals in 1966 to approximately 6,000 to 8,000 in 1992. Humpback whales are 

found in southern California waters primarily during spring and fall migrations, but 

feeding concentrations also occur during the summer. 

There are some indications that blue whale populations in coastal waters of 

California may be increasing. It is unclear whether increased numbers of blue whales are 

due to an increase in the population or to more extensive use of California waters for 

feeding. Larkman and Viet (1998) did not detect any increase in blue whales in the 

Southern California Bight from 1987 to 1995. Blue whales occur in southern California 

waters primarily during late spring and summer, where they feed in deep offshore waters. 

There is some indication that fin whales may be increasing off California, 

although the trends are not significant (Carretta et al. 2002). Fin whales occur in 

southern California waters during the summer along the continental slope and offshore 

waters. The highest concentrations are reported from offshore waters north of Point 

Conception. 

There are no data available on current population trends for Sei whales. In 

southern California, Sei whales occur in small numbers primarily during the spring and 

summer in offshore waters but may also occur in waters over the continental slope. 

The northern right whale is probably the most endangered of the large whale 

species (Koski et al. 1998). Despite full protection since 1931, the North Pacific 

population is estimated at between 50 and 200 animals (American Cetacean Society 

[ACS] 2003a). Recent sightings have been near shore in continental shelf waters, but 

there have been more opportunities for sightings in inshore than offshore waters (Koski et 

al. 2002). Most sightings have been of single animals in winter or early spring. 

Some cetaceans have displayed remarkable population recoveries in recent years. 

The gray whale was recently removed from the U.S. list of endangered species, and the 

eastern North Pacific population now numbers between 19,000 and 23,000 animals 

(ACS 2003b). Gray whales occur in both inshore and offshore waters of California 

during their southward migration from late December through February and their 

northward migration from mid-February through May. 
92 

Pinnipeds 

Six species of pinnipeds may occur in the waters of the Southern California Bight 

(Table 5.8), including harbor seal, northern elephant seal, California sea lion, Steller sea 

lion, and Guadalupe and northern fur seals. 

Table 5.8 

Common and Scientific Names, Abundance, Status, and Seasonal Occurrence of 

Pinniped Species and the Southern Sea Otter (Mustelid) Present in the Southern 

California Bight

Species Occurrence Status Season 

Seals (Family Phocidae) 

Harbor seal Common Protected Year-round 

 Phoca vitulina 

Northern elephant seal Common Protected Year-round 

 Mirounga angstirostris 

Fur seals and sea lions (Family Otariidae) 

California sea lion Common Protected Year-round 

 Zalophus californianus 

Steller sea lion Rare Threatened, depleted, strategic Vagrant 

 Eumetopias jubatus 

Guadalupe fur seal Rare Threatened, depleted, strategic Unknown 

 Arctocephalus townsendi 

Northern fur seal Common Protected Year-round 

 Callorhinus ursinus 

Sea otter (Family Mustelidae) 

Southern sea otter Rare Threatened, depleted, strategic Year-round 

 Enhydra lutris nereis 

The California harbor seal population has dramatically increased since the 1960’s 

and may be around 30,000 animals (Koski et al. 1998). In some areas, the populations 

may be stable or declining either because they have reached their carrying capacities or 

because they may be limited by competition with northern elephant seals. During most 

of the year, harbor seals are found in nearshore areas where they feed in waters from 

10 to 120 m in depth. 

The northern elephant seal population in California has increased since 1900. The 

California population is estimated at approximately 84,000 animals, most of which use 

haul-outs on islands off southern California with the largest numbers on San Miguel and 

San Nicolas islands (Koski et al. 1998). Northern elephant seals also breed on islands of 

the west coast of Mexico, and some of the population increases in the southern California 

stock may have resulted from emigration of Mexican seals. Northern elephant seals 

spend most of the year feeding in offshore waters but haul out on beaches to give birth, 
93 

breed, and molt. Elephant seals feed in deeper water than harbor seals and may dive to 

800 m. 

The California sea lion is the most common pinniped in Southern California. The 

California sea lion population may number around 200,000 animals, and more than 

95% of the U.S. stock is associated with haul-outs on San Miguel and San Nicolas islands 

(Koski et al. 1998). Breeding haul-outs are also located on islands off the west coast of 

Mexico and the Sea of Cortez. Smaller haul-outs occur from Point Conception to the 

California/Oregon border. After breeding, California sea lions migrate to offshore 

feeding areas and may move as far north as Puget Sound and British Columbia. 

The western stock of the Steller sea lion is listed as endangered, and the eastern 

stock is listed as threatened under the ESA and is being considered for endangered status 

due to declines in the Alaskan populations. Steller sea lions formerly bred on San Miguel 

Island but the southernmost breeding colony is now Año Nuevo Island off central 

California. They are rarely sighted in the waters off southern California. Steller sea lion 

is considered as depleted under the MMPA, and the Eastern stock, which occurs in 

California waters, is considered a strategic stock. 

The Guadalupe fur seal was near extinction in the late 1800’s due to commercial 

sealing activities. The main breeding colony is located on Isla Guadalupe off the coast of 

Baja California. In 1997, a second colony was discovered south of Isla Guadalupe on 

Isla Benito del Este and a pup was reported on San Miguel Island. Over the last 30 years, 

the Guadalupe fur seal annual growth rate has been 13.7% (Koski et al. 1998; Carretta 

et al. 2002) and the population numbers around 7,000 animals, most of which are 

centered on Isla Guadalupe. The Guadalupe fur seal appears to be expanding its range, 

and the number of sightings in the waters off southern California has been increasing in 

recent years. The Guadalupe fur seal is listed as threatened under the ESA and as a 

depleted and strategic stock under the MMPA. 

Most of the U.S. population of northern fur seals breeds on the Pribilof Islands in 

the Bering Sea. Small colonies also are located on Bogoslof Island in the southern 

Bering Sea and on San Miguel Island off southern California. The San Miguel Island 

stock originated from the Pribilof Island stock during the late 1950’s or early 1960’s and 

was discovered in 1968 (Carretta et al. 2002). Since then, the colony has increased 

steadily with the exception of declines in 1983 and 1998 that were associated with El 

Niño Southern Oscillation events. Although the eastern Pacific stock from the Bering 

Sea was listed as depleted under the MMPA in 1988, the San Miguel Island stock is not 

considered to be depleted, or threatened or endangered under the ESA. The most recent 

estimate for the San Miguel Island stock is 4,336 animals. During the winter, female and 

juvenile northern fur seals from the depleted eastern Pacific stock of the Bering Sea 

migrate south, and fur seals in the waters off southern California may be either from this 

stock or the San Miguel Island stock (Koski et al. 1998). 
94 

Mustelids 

The southern sea otter is the only other marine mammal known to occur in the 

waters of the Southern California Bight. Sea otters were exploited for their pelts during 

the 1700’s and 1800’s; their numbers dropped drastically, and they were extirpated from 

some areas. In 1911, sea otters were given full protection under the Fur Seal Treaty. 

Recovery efforts have been variably successful. The State of Alaska successfully 

reintroduced sea otters into areas of unoccupied habitat, and sea otter numbers have been 

increasing (Alaska Department of Fish and Game [ADFG] 2002a). The southern or 

California population has grown more slowly and is restricted primarily to coastal waters 

from Point Año Nuevo to Purisima Point but has been expanding its range south into the 

western portions of the Santa Barbara Channel area. A small transplanted population is 

also located around San Nicolas Island, results of an effort to establish a colony removed 

from the mainland population. The California southern sea otter population contains 

approximately 2,400 animals (Koski et al. 1998) and is listed as threatened under the 

ESA; it is categorized as depleted and listed as a strategic stock under the MMPA. 

5.3.3 Alaska OCS Region 

Federal OCS oil and gas production activities offshore Alaska are restricted to 

two separate regions – Cook Inlet and nearshore waters of the Beaufort Sea. Platform 

removal is only expected to occur in the Cook Inlet (i.e., only gravel islands are used for 

offshore oil and gas production on the Beaufort Sea shelf); at present, only one platform 

occurs in Federal OCS waters of Cook Inlet. The following discussion of marine 

mammals in the Alaska OCS Region will be focused on the Cook Inlet region. Marine 

mammals of Alaska are described in Angliss and Lodge (2002), Perrin et al. (2002), and 

Wynne (1997). 

The most intensely studied marine mammal in the Cook Inlet area is the beluga 

whale (Delphinapterus leucas). The Cook Inlet beluga population occurs in the inlet and 

Shelikof Strait region, although wanderers have been seen east to Yakutat Bay and to 

Kodiak Island. Belugas are toothed whales that often ascend large rivers, where they 

feed on anadromous fishes and appear to be unaffected by salinity changes. During the 

summer they also feed on herring, capelin, smelt, arctic and saffron cods, flatfishes, 

sculpins, octopus, squid, shrimp, crabs, and clams (ADFG 2002b). 

The Cook Inlet beluga stock was subjected to unregulated harvest until 1999 and 

was listed as depleted under MMPA in May 2000 (Federal Register 65:34,590). The 

Cook Inlet stock is now managed with a small, regulated harvest. NMFS has conducted 

annual aerial surveys during June and July for beluga whales and other marine mammals 

in Cook Inlet since 1993. Index counts, which are uncorrected for whales that may have 

been outside of the observers’ view, have ranged from 174 to 217 since 1998 (Rugh et al. 

2003). These counts are lower than those reported from 1993 to 1997 that ranged from 

264 to 324. In 2003, as in most years, belugas were found in small groups near river 

mouths along the northwestern shores of upper Cook Inlet, in particular near Beluga 

River, Susitna River, Little Susitna River, and across the middle of Knik Arm, as well as 
95 

along the shores of Chickaloon Bay; no belugas were reported south of the Forelands in 

lower Cook Inlet. Prior to 1996, it was not uncommon to see groups of belugas south of 

the Forelands, but since then there have been few sightings in the lower inlet (Rugh et al. 

2003). 

During the NMFS 2003 aerial survey, harbor seal (Phoca vitulina) was the only 

other marine mammal observed in upper Cook Inlet (Rugh et al. 2003). Harbor seals are 

generally associated with coastal areas, although they occasionally are observed well 

offshore. In Alaska, harbor seals feed on pollock, Pacific cod, capelin, eulachon, Pacific 

herring, salmon, octopus, and squid (ADFG 2002c). During the NMFS 2003 survey, 

harbor seals were concentrated (i.e., up to 50 individuals) in upper Cook Inlet at 

Chickaloon Bay, and between the Beluga and Susitna rivers, where as many as 

200 individuals were sighted. In the lower inlet, harbor seals were concentrated in 

Kachemak Bay (140 individuals at Bradley River), Big River (130 individuals), and in or 

near Tuxedni Bay (100 individuals). There was a total of 36 harbor seal sightings 

totaling 974 individuals. No marine mammals were reported in Cook Inlet north of 

Kachemak Bay during the NMFS 2003 aerial survey other than beluga whales and harbor 

seals. 

Steller sea lions (Eumetopias jubatus) were reported during the 2003 aerial 

surveys in lower Cook Inlet near Elizabeth Island, where 76 animals were hauled-out on 

the south shore and one other seal lion was seen in the water nearby. The Alaska 

population of Steller sea lions was estimated at approximately 242,000 animals in the 

1970s, but declined by about 50% by the mid-1980’s. The reasons for the decline are 

unclear but may be related to food availability and/or global climate change. Under the 

ESA, Steller sea lions west of Cape Suckling, Alaska are listed as endangered and those 

east of Cape Suckling are listed as threatened. Steller sea lions feed on a variety of 

fishes, including pollock, flounder, herring, capelin, Pacific cod, salmon, rockfish, 

sculpins, and invertebrates such as squid and octopus (ADFG 2002d) and may compete 

with commercial fisheries. 

Three other pinniped species – northern fur seal (Callorhinus ursinus), northern 

elephant seal (Mirounga angustirostris), and Pacific walrus (Odobenus rosmarus) – may 

also occur in Cook Inlet (MMS 1996). These species occasionally occur in the lower 

Cook Inlet/Shelikof Strait area but were not observed during the 2003 aerial survey. 

During the 2003 Cook Inlet aerial surveys, sea otters (Enhydra lutris) were 

common in lower Cook Inlet, as in previous years (Rugh et al. 2003). Sea otters were 

exploited for their pelts during the 1700’s and 1800’s; their numbers dropped drastically, 

and they were extirpated from some areas. As noted previously, sea otters were given 

full protection under the Fur Seal Treaty in 1911. The State of Alaska successfully 

reintroduced sea otters into areas of unoccupied habitat, and by the mid-1970’s the 

Alaskan population numbered between 110,000 and 160,000 animals (ADFG 2002a). 

During the 2003 aerial surveys in Cook Inlet, there were 39 sightings totaling 291 otters 

in groups of from 1 to 50 individuals. All sightings were in areas south of Kachemak 

Bay, and no sea otters were reported from the upper inlet. 
96 

Humpback whales (Megaptera novaeangliae) and fin whales (Balaenoptera 

physalus) were reported at three locations along the southern limits of Cook Inlet during 

the 2003 aerial survey: 1) between Augustine Island and the Barren Islands (i.e., 

five humpback, three fin whales); 2) north of the Barren Islands (12 humpback, 13 fin 

whales); and 3) west of Kachemak Bay (three humpback whales sighted on two survey 

dates). Other cetaceans that can occur in the area but were not observed during the 

2003 survey include killer whale (Orcinus orca), harbor porpoise (Phocoena phocoena), 

Dall’s porpoise (Phocoenoides dalli), Pacific white-sided dolphin (Lagenorhynchus 

obliquidens), gray whale (Eschrichtius robustus), minke whale (Balaenoptera 

acutorostrata), Baird’s beaked whale (Berardius bairdii), and Cuvier’s beaked whale 

(Ziphius cavirostris) (MMS 1996). In addition, sperm whale (Physeter macrocephalus),

Sei whale (Balaenoptera borealis), right whale (Eubalaena [=Balaena] japonica), and 

blue whale (Balaenoptera musculus) may wander into the area. 

5.3.4 Marine Mammal Survey Data Limitations 

Effective monitoring and mitigation of the impacts of explosives on marine 

mammals depends on the ability to detect them. Visual detection is a function of the 

group size, time spent at the surface, and behavior of the animals. Large groups of small 

odontocetes that travel in groups of a hundred, make short shallow dives, and make a 

habit of leaping into the air are more likely to be seen than manatees that are found in 

small groups and do not leave much of an indication of their presence at the surface. 

Species that make long dives, such as sperm whales and beaked whales, may not spend 

much time at the surface and so will be difficult to detect visually. 

 One of the mitigation measures for underwater detonations is aerial surveys to 

detect the presence of marine mammals and to suspend the explosion if mammals are 

present. The g(0) function in (e.g., see Table 5.6) is the probability of an animal being at 

the surface at any instance in time. This function and specific density of a particular 

species at the time and place of the test (Davis et al. 2000) can be used to design a survey 

program that is optimal for detecting marine mammals. 
97

CHAPTER 6

ENVIRONMENTAL CONSEQUENCES

6.1 Marine Fishes

Those who collect fish for a living (fishers and ichthyologists) have long

exploited the fact that fishes readily succumb to underwater explosions. Islanders from

the Indo-Pacific region (Indonesia, Papua New Guinea, and the Philippines) have fished

with explosives since World War II when ordnance and explosives left behind provided

the basis for a new and effective method of harvesting reef fish (Ronquillo 1950; Alcala

and Gomez 1987; Saila et al. 1993; McManus et al. 1997; Pet-Soede et al. 1999). In

these areas, effects of blast fishing on coral reef habitats and fish populations have been

the primary concern among resource managers and conservationists.

Similarly, blast fishing also has a history in the U.S. For example, Carr (1996)

tells of individuals using partial sticks of dynamite (called “cut bait”) to kill or stun fishes

from freshwater streams and springs in Florida. Engaging in a more professional form of

blast fishing, fish researchers seeking assessments of local fish assemblages often used

explosives in marine (e.g., Russell et al. 1978; Williams and Hatcher 1983) and

freshwater (Metzger and Shafland 1986; Bayley and Austen 1988) settings. If carefully

deployed, explosives provided quantitative samples of discrete areas without greatly

damaging the habitat structure. This was because the killing shock waves emanating

from the blast attenuate rapidly, resulting in a restricted lethal zone. Explosive sampling

offered researchers an alternative to liquid ichthyocides such as rotenone that can drift

out of a prescribed study area to create extensive and unwanted fish kills. Nevertheless,

because of safety and public perception issues, ichthyologists rarely use explosives to

sample fishes.

Although these purposeful uses of explosives to collect fishes are now against the

law or in general disfavor, there are many situations in underwater construction,

geophysical surveying, and demolition where fish kills are an unwanted side-effect of

explosive use. Explosive removal of offshore oil and gas structures is a primary example

of a situation where unwanted fish kills have become part of the process. Oil and gas

structures in the Gulf of Mexico and Pacific OCS Planning Areas attract and concentrate

large numbers of fishes as de facto artificial reefs (Sonnier et al. 1976; Gallaway and

Lewbel 1982; Putt 1982; Continental Shelf Associates, Inc. 1982; Stanley and

Wilson 1990, 1998; Love et al. 2000). Consequently, when structures are removed using

explosives, high numbers of resident fishes can be killed (Gitschlag et al. 2000).

Many of the species killed or injured within OCS Planning Areas are managed

under the Magnuson-Stevens Fishery Conservation and Management Act (16 U.S.C.

§ 1801-1882). Platforms in the Gulf of Mexico provide habitat for members of the

snapper-grouper (reef fish) management unit, red drum management unit, coastal

migratory pelagic management unit, and the highly migratory species management units

managed by the Gulf of Mexico Fishery Management Council. In the Pacific OCS
98

Planning Area, species from the groundfish management unit under the jurisdiction of the

Pacific Marine Fisheries Commission inhabit offshore platforms. As the platform

removal program progresses, resource managers from MMS and NOAA-F (NMFS) need

to determine whether there are any adverse effects to local populations and the

ecosystems they inhabit.

6.1.1 Lethal Effects of Underwater Explosions on Fishes

Effects of underwater explosives on fishes have been fairly well documented (see

reviews by Christian 1973; Hill 1978; Baxter et al. 1982; Lewis 1996; and Keevin and

Hempen 1997). The few generalities that have emerged from empirical studies indicate

that at very close range, underwater explosions are lethal to most fish species regardless

of size, shape, or internal anatomy; however, at greater distances from the source, species

with gas-filled swimbladders suffer higher mortality than those without swimbladders.

Studies also suggest that larger fishes are generally less susceptible to death or

injury than small fishes at the same distance from the source; elongated forms that are

round in cross-section are less at risk than deep-bodied forms; and orientation of fish

relative to the shock wave may affect the extent of injury. The results of most studies are

dependent upon specific biological, environmental, explosive, and data recording factors.

The following subsections contain reviews of available information with attention to

lethal and sublethal effects of underwater explosions on fishes. Under the lethal heading,

causes of death, documented fish kills (particularly those associated with platform

severance), experimental studies, and predictive modeling of lethal ranges are described.

Causes of Injury

Understanding lethal effects of underwater explosion requires identification of

causes of death and factors that contribute to variation in those causes. For most

situations, cause of death in fishes has been massive organ and tissue damage and internal

bleeding. These causes are related to fish size, species, and to a lesser extent orientation

with respect to the incoming shock wave.

Fish are most often killed or injured by the shock wave generated by an

underwater explosion. The precise component of the shock wave responsible for injury is

not known. Damage is usually found in visceral organs, but also can include general

tissue damage to fishes in close proximity to the detonation site. Field studies of injuries

associated with free swimming and experimentally caged fishes have documented that

most lethal injuries involve damage to visceral organs (e.g., Alpin 1947; Ronquillo 1950;

Teleki and Chamberlain 1978; Wiley et al. 1981; Linton et al. 1985). The most

commonly injured organs are those with air spaces that are affected by the explosion’s

shock wave passing through the body of the fish. These spaces include the body cavity,

pericardial sac, and gut, but the primary air space in fishes is the swimbladder.

Swimbladder injuries were most frequently observed in field monitoring and

experimental investigations (e.g., Christian 1973; Wiley et al. 1981; Linton et al. 1985;

Keevin and Hempen 1997).
99

The swimbladder is a gas-filled sac that functions as a hydrostatic organ allowing

the fish to control its buoyancy. Gases from the blood are exchanged with the swim

bladder through a circulatory apparatus called the rete mirable (wonderful net) (Jones and

Marshall 1953). When pressures oscillate rapidly as they do when an explosive shock

wave passes through the fish, the swimbladder will expand and contract rapidly to the point

of rupturing (Wiley et al. 1981). There is evidence that damage to proximate organs,

particularly the kidneys (which lie just dorsal to the swimbladder in most species), can

occur when the expanding swimbladder compresses them (Keevin and Hempen 1997).

Swimbladders vary in structure and presence on broad phylogenetic scales (Liem

1988). Swimbladders are a characteristic of bony fishes not present in sharks, rays, and

their allies. Within the bony fishes there are phylogenetic divisions that include, among

other traits, modifications to the swim bladder (Jones and Marshall 1953; Liem 1988). In

some ancestral fishes the swimbladder is connected via a pneumatic duct to the esophagus,

allowing the fish to gulp air. This condition is called physostomus. Catfishes, carps,

herrings, salmons, and tarpon are physostomus. Species exhibiting the derived condition

(no connection to the esophagus) are called physoclistus. Although physoclistus species

use the swimbladder primarily as a hydrostatic organ, some use it to aid in hearing and in

sound production (Hawkins 1986). Most common bony fishes are physoclistus, however

some, including flatfishes (Pleuronectiformes), eels (Anguilliformes), and others, do not

have swimbladders.

Fish without swimbladders are certainly less vulnerable to shock wave impacts at

a distance from underwater explosions, but they will be killed by physical force located

very close to the explosive source. Goertner et al. (1994) recorded immediate death for

hogchoker (Trinectes maculatus) and summer flounder (Paralichthys dentatus)

specimens placed within 0.5 to 2 m from the explosive source. Individuals were killed by

loss of blood as a result of hemorrhaging in the gills. This may have been caused by

radial oscillation of gas microbubbles (0.1 mm diameter) in the gill epithelium. In

addition, there was hemorrhaging in the cranium caused by differential motion of the

otoliths.

Of the 55 fish taxa killed during platform removals in the Gulf of Mexico

(Gitschlag et al. 2000), most were swimbladder species. Most were physoclists, but

several physostomes were included. The only taxa reported that do not have

swimbladders were an unidentified eel, searobin (Prionotus sp.), and molley miller

(Scartella cristata). The top species killed were generally deep-bodied types that were

surely ventrally exposed to removal blasts buried in the structures.

Other factors contributing to injury or death are fish size, body shape, orientation,

and species. Yelverton et al. (1975) experimentally determined that LD50 (50%

mortality) for various fish species exposed to explosions increased with weight of the

fish. They used fishes weighing from 0.02 to 800 g to performed dose-response

experiments at varying distances from the explosive source. Their dose-response figure,

including LD50, LD1, and no effect curves, is reproduced in Figure 6.1.
Figure 6.1. Response of fish to underwater blast as a function of impulse strength and body weight (Adapted fro

1975).

Body Weight (g)

0.01 0.1 1 10 100 1,000 10,000

Impulse Strength (psi msec)

0.1

1

10

100

50% Mortality1% MortalityNo Injuries
101

Orientation of the fish relative to the oncoming shock wave can greatly influence

the degree of injury sustained by caged fishes (Sakaguchi et al. 1976). Fishes facing head

on to the wave sustained less injury than fishes exposed broad-side to the shock wave.

Fishes with the ventral side exposed were most damaged. This aspect has not been

investigated for a wide range of species.

Contributing most to variation and uncertainties in the experimental setting are

species-specific vulnerability to underwater shock waves. Some asserted that

physostomus species would be less susceptible to pressure changes because of the outside

connection to the swimbladder (Christian 1973; Teleki and Chamblerlain 1978).

However, pressure changes created by underwater explosions are much too rapid for

physostomus fish to respond physiologically. Even though there is an opening to the

outside through the pneumatic duct, the opening is very small and structurally unable to

expel gas at a rate that would prevent rapid expansion of the swimbladder. This fact has

prompted some to suggest that there is no practical difference in the vulnerability of

physostomes and physoclists. Within physoclists there are species-specific differences in

swimbladder structure that may contribute to variation in observed injuries (Wiley et al.

1981). Species-specific body morphology and rigidity have been suggested to affect the

injury level in some species. Expanding swimbladders will injure adjacent organs,

particularly the kidneys. In species such as toadfish (Opsanus tau), where the

swimbladder is positioned away from vital organs, there may be fewer mortalities

(Wiley et al. 1981).

Documented Effects of Underwater Explosions on Fishes

Monitoring studies have documented that fishes are killed during planned

underwater explosions. Investigators in these studies have collected representative

samples of fishes killed during planned explosions and in some cases tried to estimate

regional or local scale population effects of the kills associated with underwater

explosions (Alpin 1947; Ronquillo 1950; Fry and Cox 1953; Nix and Chapman 1985;

Gitschlag and Herczeg 1994; Gitschlag et al. 1997, 2000). Fishes collected during these

studies have mostly been recovered floating at the waters surface following an explosion.

Studies that employed scuba divers to retrieve fishes from the bottom following an

explosion indicate that as few as 3% of the specimens killed during a blast may float to

the surface (Gitschlag et al. 2000). Other impediments to accurate characterization of

fish kills include currents and winds that may transport floating fishes out of the sampling

area before field crews can recover them. Additionally, predation by seabirds or other

fishes can be substantial, particularly on smaller specimens.

Of the monitoring studies available, the most relevant to this review were the

monitoring of fishes killed (and floating) around oil and gas structures in the northern

Gulf of Mexico from 1986 to 1998 by the NMFS (Gitschlag and Herczeg 1994;

Gitschlag et al. 1997, 2000). Monitored structures included platforms, submerged wells,

caissons, and flare piles. In 1992, 42% of the removals occurred in water depths of

≤15 m, and 55% occurred in depths ranging from 15 to 60 m. Most removals occurred

offshore Louisiana in an area bounded by Grand Isle, LA to the east and the Sabine River
102

to the west. Observers only counted fish floating on the surface during these surveys.

Most were killed during platform removals, followed by caisson removals, submerged

structures, and flare piles (Table 6.1). The average number of floating fish per structure

was 567 for platforms, 133 for submerged wells, 109 for caissons, and 41 for flare piles

(Table 6.1). Numerically dominant fishes killed, in decreasing order of abundance, were

spadefish (Chaetodipterus faber), red snapper (Lutjanus campechanus), vermilion

snapper (Rhomboplites aurorubens), hardhead catfish (Arius felis), blue runner (Caranx

crysos), sheepshead (Archosargus probatocephalus), tomtate (Haemulon aurolineatum),

and lane snapper (Lutjanus synagris).

Table 6.1

Estimated Number of Dead Fishes Floating at the Surface After Detonations During 1986

to 1998 (From: Gitschlag et al. 2000)

Structure Type

Number

of

Structures

Average Number of

Floating Fish per

Structure

Total Estimated

Number of Floating

Fish

Platform 742 567 420,932

Submerged well 57 133 7,554

Caisson 252 109 27,372

Flare pile 7 41 285

As previously mentioned, the platform monitoring studies described above only

collected floating fishes. In an effort to gather more quantitative and realistic measures

of fishes killed during explosive removals, Gitschlag et al. (2000) collected both floating

and sinking fishes killed during removal of nine platforms in the northern Gulf of

Mexico. Scuba divers collected dead fishes that had settled to the seafloor around these

platforms. Study platforms were located in 14 to 36 m water depths and bounded by

Longitudes 89 ̊ and 95 ̊ W (eight offshore of Louisiana and one offshore of Texas).

Investigators sampled both floating and sinking fishes at various distances up to 100 m

from the study platforms. They also employed pre-blast tagging of fishes to provide an

estimate of pre-blast population sizes using standard mark-recapture methods. Only

fishes greater than 8 cm were tallied for the mortality estimates in the report (Gitschlag

et al. 2000).

A total of 30,315 individuals represented by 55 fish taxa in 23 families (combined

floaters and sinkers >8 cm total length) was recorded from the nine platforms. The

number of taxa per platform averaged 14.4 and ranged from 8 to 20. The number of

individuals estimated at each platform averaged 3,390 and ranged from 1,765 to 5,216.

These values indicate the underestimation of mortality that results from counting only

floating fishes. Spadefish, red snapper, sheepshead, blue runner, and gray snapper

collectively contributed 90% of the total numbers sampled. Explanatory factors such as

platform age, water depth, longitude, surface salinity, surface temperature, and season

were weakly correlated with mortality of any of these species.
103

Most of the fishes recovered by Gitschlag et al. (2000) were found within 25 m of

the platform. Numbers decreased with distance out to 100 m, the greatest extent to where

divers searched for dead fishes. This suggests that most of the fishes were very close to

the structure, corroborating Stanley and Wilson’s (1998, 2000) estimate of 18 to 50 m as

the primary distance envelope for platform-associated fishes.

Although the study by Gitschlag et al. (2000) was very thorough in the

documenting of fishes killed by platform removals, the authors point out that any

generalization beyond the geographical area, water depth range, season, fish species, and

size ranges should be done with caution.

Monitoring studies document species composition and relative numbers killed,

but they rarely record information on the shock waves or provide insights into lethal

ranges for various explosives. Researchers have been searching for the precise

component of the shock wave that will provide a general prediction of lethal zones for

underwater explosions (e.g., Hubbs and Rechnitzer 1952; Linton et al. 1985; Goertner

et al. 1994; Keevin and Hempen 1997). Physical properties of shock waves that have

been empirically or theoretically correlated with fish mortality are impulse level, which is

the time-pressure integral of the shock wave reported in Pa-s units; energy flux density,

which is the rate of energy transport over a unit area reported as J/m2

; and peak pressure,

the maximum pressure of the initial shock wave reported in Pa.

Peak pressure is often considered an important component of the shock wave in

experimental situations. A 60% reduction in relative pressure was considered to be

sufficient to burst the swimbladder of a physoclistus fish (Jones 1951, 1952). Hubbs and

Rechnitzer (1952) reported lethal threshold peak pressures ranged from 40 to 70 psi

(276 to 482 kPa) for dynamite. These investigators also found that black powder charges

as high as 1,100 kPa were not lethal to fishes. These observations were confirmed in

California coastal waters by Fry and Cox (1953) and by Ferguson (1962) for freshwaters.

Black powder has a slow detonation (deflagration) velocity (i.e., relatively slow rise time

and peak pressure; see Chapter 3, Table 3.1 and Chapter 4). Keevin and Hempen

(1997) found that detonation velocity was not a factor in fish mortality with

commercially available explosives. They believe that the slow rise time (to peak)

pressure was the characteristic that made black powder charges less lethal to fishes.

Keevin and Hempen (1997) measured energy flux density, impulse strength, and

peak pressure associated with experimental detonations to determine lethal ranges for

caged bluegill (Lepomis macrochirus). All three measures were correlated with fish

mortality, but impulse strength varied the least. They found an immediate increase in

damage to internal organs at levels above 700 kPa peak pressure, 50 pa-s impulse (from

the first positive wave), and 40 J/m2

. Mortality increased at levels above 500 kPa,

40 pa-s, and 20 J/m2

. The lower levels for mortality were due to the mortality scoring

system used that treated minor injuries as deaths. Measured LD50 values for bluegill in

these trials were about 40 m.
104

Effects on Early Life Stages

There have been few investigations of the effects of underwater explosions on

early life stage (egg, larval, juvenile) fishes. Fitch and Young (1948) reported that larval

anchovies died when exposed to underwater blasts off California, and Nix and Chapman

(1985) found that anchovy and smelt larvae died following the detonation of buried

charges. Yelverton et al. (1975) demonstrated that smaller sized fishes were less

sensitive to shock waves than larger ones at similar distances from the explosive source.

The LD50 for larval guppy (Lebistes reticulatus) was estimated to be 1.7 psi ms

(11.7 kPa-s) (Brown 1939). Settle et al. (2002) reported total injury dose (the sum of

lethal and sublethal fractions) of 8.9 Pa-s for spot and 5.3 Pa-s for pinfish.

As with adult fishes, the presence of a swim bladder contributes to internal

damage in larval and juvenile fishes (Settle et al. 2002). Timing of swimbladder

development varies with species, but its presence is important in the survival of larval

fishes (Egloff 1996). Settle et al. (2002) used controlled cage experiments with two

larval fish species, spot (Leiostomus xanthurus) and pinfish (Lagodon rhomboides) to

determine lethal distances and to assess internal damage. Trauma to internal organs of

test fishes was verified histologically by Govoni et al. (2002). Specimens exposed to the

strongest shock waves had injured kidneys, swimbladder, liver, and pancreas. They

stated that the most common injury to spot and pinfish was hematuria (damage to kidney

tubules). Other trauma observed were hemorrhage within the coelom, swimbladder

hemorrhage, liver hemorrhage, coagulative liver necrosis, and ruptured pancreas. These

authors did not observe swim bladder rupture in field tests with larval spot and pinfish.

6.1.2 Sublethal Effects

Lethal consequences of underwater blasts involve traumatic damage to tissues and

viscera in individuals within close range of the explosion. Some sublethal effects also

may be expected due to this type of damage, but sublethal effects are more likely to

involve impacts to hearing, sound detection, and sound production in individuals

occurring at greater distances from explosion sources. These functions are important to

the ecology and behavior of individuals, and may be temporarily or permanently altered

by exposure to explosion (e.g., Myrberg 1981; Hawkins 1986). Any effects that would

lead to reduced survival, growth, or reproductive output could lead to population level

impacts. There is little information on sublethal effects of underwater explosions,

however the effects would likely be in terms of unusual behavior. Such behavior would

probably result from injury to hearing, orientation, and endocrine and nervous systems.

Teleost fishes detect pressure or shock waves in the inner ear and balance detection

apparatus. The inner ear system detects a pressure wave when it is sufficiently strong to

move the body of the fish relative to its otoliths, the stony structures that lie inside the

semicircular canal system of the inner ear. There are three pairs of otoliths, and each is

encased in an individual chamber lined with sensory hair cells upon which the otoliths are

balanced. Otoliths are denser than the body of the fish (specific gravity of 2 or 3), and thus

have more inertia than the fish. The hair cells have nervous connections that transmit the
105

information on otolith position to the brain. Fishes also detect sound using the

swimbladder and acoustico-lateralis system. Continental Shelf Associates, Inc. (2002)

reviewed the general effects of noise on fishes. This report stated that all fish species

investigated can hear, with varying degrees of sensitivity, within the frequency range of

sound produced by underwater explosions. These sounds can mask the sounds normally

used by fishes in their normal acoustic behaviors at levels as low as 60 to 80 dB (just above

detection thresholds for many species). Levels as high as 160 dB may cause receiving

fishes to change their behaviors and movements, which may temporarily affect the usual

distribution of animals and commercial fishing. Continuous, long-term exposure to levels

above 180 dB has been shown to cause damage to the hair cells of the ears of some fishes

under some circumstances. These effects may not be permanent since damaged hair cells

are repaired and/or regenerated in some fishes. However, McCauley et al. (2003) found

irrepairable hair damage for species exposed to 180 dB seismic air gun noise. It is not clear

if permanent hair cell damage could occur in response to underwater shock waves, but

observations of behavioral alterations have been made during experimental studies. For

example, Goertner et al. (1994) reported impaired swimming and disorientation in test

fishes located well outside the lethal zone of the explosive source.

Shock waves produced by underwater explosions could affect behavior of larval

fishes seeking shelter or settlement sites. Some reef fish larvae have been shown to

respond to sound stimuli as a sensory cue to settlement sites (Stobutzki and Bellwood

1998; Tolimieri et al. 2000). Damage to hearing mechanisms in larvae could impair the

ability of newly settled fishes to locate preferred substrate.

Sverdrup et al. (1994) examined the effects of seismic noise on endocrine function

in farm-reared salmon. They found evidence of temporary vascular impairment of vascular

endothelium, but no appreciable alteration of plasma levels of adrenaline or other stress

hormones.

6.1.3 Prediction of Lethal Range

Field studies provided the impetus and data needed to develop and validate

predictive models of lethal range or lethal zones for fishes using various physical

properties of the shock wave produced by underwater explosions. These properties

include compressional wave, peak pressure, impulse strength, bulk cavitation, and energy

flux density. Several authors have reviewed the chronology and development of lethal

range models for fishes (Christian 1973; Baxter et al. 1982; Lewis 1996; Keevin and

Hempen 1997). The ability of models to accurately predict mortality or injury in fishes

exposed to underwater shock waves is affected by numerous biological, environmental,

explosive, and data acquisition factors (Keevin and Hempen 1997) (Table 6.2). Despite

acknowledged uncertainties, models can be useful in predicting mortality and

determining lethal zones expected for underwater explosions. Canada uses predictive

models as part of their pre-explosive management program (Wright and Hopky 1998).
106

Table 6.2

Factors That Can Affect Fish Mortality, Making Precise Predictions of Mortality Difficult

(From: Keevin and Hempen 1997)

Biological

 Size

 Shape

 Orientation

 Anatomy

Environmental

 Air-water roughness

 Water-bottom roughness

 Water bottom acoustic impedance (bottom type)

 Water temperature

Explosive

 Depth of explosive

 Relative bulk strength of explosive

 Surface, mid-column, or buried charge

 Pressure reduction from confined shot

Data Acquisition

 Accuracy of pressure transducers and recording equipment

 Pressure wave processing techniques

 Standardization of pressure wave form calculations

The most common models in use today are the impulse strength model (Hill 1978;

Munday et al. 1986), energy flux density model (Sakaguchi et al. 1976; Baxter 1985), and

the dynamical or swimbladder oscillation model (Wiley et al. 1981). Christian (1973)

reviewed models based on charge weight and peak pressure and concluded that neither

approach was appropriate, instead proposing that bulk cavitation should be considered as

an important factor in fish kills because this process would cause rapid expansion and

compression of swimbladders. Nevertheless, results from bulk cavitation models did not

correlate well with observed fish mortality (Gaspin 1975), and increasing the charge

weight did not result in a corresponding increase in the size of the cavitation zone as

expected. Gaspin’s (1975) attempts did reveal that total pressure drop was an important

factor in mortality.

Impulse strength is considered the most important shock wave property for

predicting damage or death in water depths less than 3 m (Baxter et al. 1982), and energy
107

flux density was considered to be the best predictor in deeper water (Sakaguchi et al.

1976).

Young (1991) provides equations for calculating lethal ranges using the dynamic

model. This dynamic model relates weight of charge to swimbladder oscillation

parameters that are determined individually for each fish species. The dynamic model

treats the swimbladder as a spherical gas bubble, and its motion under the influence of an

explosive pressure wave is calculated. Fish damage is calculated under the parameters of

the calculated motion; however, this approach depends upon fish size and water depth.

Young’s (1991) equations were used to estimate a 10% mortality range or safe

range, i.e., the area beyond which 90% of the fishes will survive a charge of given weight

for reef and coastal pelagic fishes common to Gulf of Mexico oil and gas structures. The

safe ranges for swim bladder fishes were calculated as follows:

RSF(meters) =43 WF

-0.13WE0.28D0.22

where RSF is safe range in meters, WF is fish weight in pounds, WE is charge weight in

pounds, and D is charge depth in feet.

For non-swimbladder fishes, Young (1991) provided the following equation:

RSF=3.38 WE

0.33

Safe ranges for swimbladder fishes are clearly much greater than those estimated for

non-swimbladder fishes (Table 6.3). The values for the reef fishes all exceed 200 m, and

therefore exceed the 50 m envelope identified by Stanley and Wilson (1998, 2000) where

most of the platform-associated species reside. Safe ranges for the coastal pelagic species

are very close to the detonation source, possibly closer than these species would get.

It is important to note that all of the models discussed above, including those used

in Table 6.3, assume mid-water or open water explosions. Severance of platform legs

and associated structures obviously will employ buried charges. Clearly, there are

differences in the explosive characteristics of buried charges when compared with open

water charges. Baxter (1985) estimated that the effect of charge weight for buried

charges would be less by a factor of about 5. Interestingly, the compression wave may be

as much as 7 times stronger but it will decay much faster than an open water wave. The

nature of the shock wave emanating from a buried charge is very complex, and models

are more difficult to apply (Heathcote 1981; Baxter et al. 1982; Munday et al. 1986).

Cumulative Effects

Because oil and gas structures concentrate fishes in high numbers and those

individuals tend to remain very close to the structures, explosive removal will continue to

kill fishes as abandonment programs progress. Managers must view this mortality from

two cumulative perspectives. The first asks how mortality from explosive platform
108

Table 6.3

Estimated Safe Range for Select Reef and Coastal Pelagic Species. The 10% Mortality

Range is the Distance from the Detonation Point Beyond Which 90% or More of the

Fishes Would Survive. Calculations are Based on Young (1991) Assuming a 23-kg

(50-lb) Charge Detonated at a Depth of 15 m (50 ft) Below the Surface

Fish

Fish

Weight

(lbs)

Swimbladder Safe Range

(m)

Reef Species

 Red Snapper (Lutjanus campechanus) 5 yes 230

 Sheepshead (Archosargus probatocephalus) 3 yes 259

 Atlantic spadefish (Chaetodipterus faber) 2 yes 246

 Lane snapper (Lutjanus synagris) 1 yes 310

 Vermilion snapper (Rhomboplites aurorubens) 0.2 yes 349

Coastal Pelagic Species

 King mackerel (Scomberomorus cavalla) 15 no 12

 Spanish mackerel (Scomberomorus maculatus) 3 no 12

 Little tunny (Euthynnus alletteratus) 8 no 12

removal contributes cumulatively along with other sources of mortality such as fishing,

trawl bycatch, and natural causes to fish population growth and stability. The second

asks how explosive removal affects fish populations incrementally through time.

Gitschlag et al. (2000) addressed the first question for populations of red snapper in the

Gulf of Mexico. By including platform removal mortality estimates with other sources of

mortality (fishing, natural, and trawl bycatch) used in stock assessment calculations, they

concluded that mortality of red snapper from platform removal did not adversely affect

red snapper populations in the Gulf of Mexico.

The second cumulative perspective was also discussed by Gitschlag et al. (2000).

Long-term projections about the significance of platform removal on red snapper

populations in the Gulf of Mexico will ultimately depend upon the importance of the

platforms as habitat for certain species. Gitschlag et al. (2000) estimated that 66,435 red

snapper would be killed each year by explosive removals from about 129 platforms. The

incremental effects over time could certainly have a cumulative effect on red snapper

populations and other federally managed fish populations if platforms prove to be critical

habitat in portions of the Gulf of Mexico.

Similar issues should be considered for the Pacific OCS Region, where

cumulative effects on populations of relatively long-lived rockfish species could be more

detrimental to local populations.
109

6.2 Marine Turtles

6.2.1 Physical Effects of Underwater Explosions

The effects of an underwater explosion on pelagic marine vertebrates such as

marine turtles are dependent upon several factors: the size, type, and depth of the

explosive charge; the size and depth of the turtle in the water column; overall water

column depth; and the standoff distance from the explosive charge to the turtle

(Department of the Navy 2001). Impacts to marine turtles are a result of physiological

responses (generally the destruction of tissues at air-fluid interfaces) to both the type and

strength of acoustic signature and shockwave generated by the underwater explosion.

Generally, blast injury, defined as biophysical and pathophysiological events and

the clinical syndromes that occur when a living body is exposed to a blast of any origin,

comprises two categories: primary blast injury (PBI) and cavitation (Department of the

Navy 2001). PBI occurs when the blast wave strikes and compresses the body, and

energy from the blast is transferred directly from the transmitting medium (air or water)

to the body surface. Injury resulting from PBI is almost totally limited to gas-containing

organs: in marine turtles, this would be primarily the auditory system and lungs (Geraci

and St. Aubin 1985). Cavitation occurs when compression waves generated by an

underwater explosion propagate to the surface and are reflected back through the water

column as rarefaction waves. The rarefaction waves, subsequently, create a state of

tension within the water column, causing cavitation (defined as the formation of partial

vacuums in a liquid by high intensity sound waves) within a bounded area called the

cavitation region. The direct effects of cavitation on marine turtles is unknown, though

(as in the case of marine mammals) it is assumed that the presence of a turtle within the

cavitation region created by the detonation of a small charge could directly annoy or

injure the animal (primarily the auditory system or lungs) or increase the severity of

PBI injuries to the animal (Department of the Navy 2001).

Quantitative data concerning direct effects of underwater explosions on marine

turtles are virtually nonexistent, consisting of observational information collected during

one study (Klima et al. 1988), as discussed later in Section 6.2.2. Therefore, a discussion

of the effects of explosions on these animals must be inferred from documented effects to

other marine vertebrates with lungs or other gas-containing organs, such as mammals.

The range of potential impacts to marine turtles has been divided into three categories:

non-injurious effects; non-lethal injuries; and lethal injuries.

Non-injurious Effects

Non-injurious effects of underwater explosions to marine turtles include acoustic

annoyance and mild tactile detection or physical discomfort.
110

Acoustic Annoyance

The anatomy of the ear of marine turtles is discussed in a general way to serve as

the basis for an analysis of the processes of sound reception in these animals. As in

mammals, most reptiles demonstrate three principal divisions of the ear: the outer ear, the

middle ear, and the inner ear. The outer ear receives sound waves from the external

environment. In turtles, the external ear is entirely absent (Wever 1978). However, the

sound-receptive and conductive mechanism of the middle ear is well developed

(Hadžiselimović and Andelić 1967; Wever 1978). Typically, the middle ear of reptiles

consists of a tympanic membrane, or tympanum, and an ossicular chain, comprising the

columella and extracolumella, suspended in an air space (the tympanic cavity) and

leading inward to the oval window to the inner ear. The tympanic cavity is connected

with the throat (pharynx) by a Eustachian tube. In marine turtles, there is no tympanic

membrane per se, but the function of such a membrane is served by a tympanum

composed of layers of superficial tissues at the side of the head that are no more than a

continuation of facial tissue over a depression in the skull that forms the middle ear

cavity (Wever 1978; Lenhardt et al. 1985; Bartol et al. 1999; Bartol and Musick 2003).

The outer layer consists of a heavy fibrous plate with a thin, scale-like surface. The

middle layer is particularly thick and contains a large amount of fatty tissue embedded in

a delicate fibrous network, a feature that distinguishes them from both terrestrial and

semiaquatic turtle species (Moein 1994). Collectively, the thick tympanum does not

inhibit overall sound reception, but rather acts as additional mass loading to the ear,

allowing for reduction in the sensitivity of sound frequencies and increasing

low-frequency, bone conduction sensitivity (Lenhardt et al. 1985; Bartol et al. 1999;

Bartol and Musick 2003).

Electrophysiological studies to determine the acoustic sensitivity of green turtle

(Chelonia mydas) and loggerhead turtle (Caretta caretta) using auditory brainstem

response (ABR) techniques found that the effective range of hearing of these species is

within low frequencies (100 to 500 Hz) (Ridgway et al. 1969, 1970; Lenhardt et al. 1994;

Moein 1994; Moein et al. 1994; Bartol et al. 1999; Bartol and Ketten 2003). Lenhardt

et al. (1983) and Moein et al. (1993, 1994) found that bone-conducted hearing appears to

be an effective reception mechanism for marine turtles (loggerhead and Kemp's ridley

[Lepidochelys kempii]), with both the skull and shell acting as receiving surfaces for

water-borne sound at frequencies encompassing the 250 to 1,000 Hz range. As high

sound frequencies are attenuated by bone, the range of bone conducted sounds detected

by marine turtles are limited to only low frequencies (Tonndorf 1972).

These data suggest that marine turtle auditory perception occurs through a

combination of both bone and water conduction rather than air conduction (Lenhardt

1982; Lenhardt and Harkins 1983).

From these studies, it is reasonable to assume that the marine turtle auditory

apparatus is sensitive to sounds produced by underwater explosions, and the air-filled

middle ear, or tympanic cavity, is sensitive to associated pressure effects. It may be

presumed that detonations of low intensity or of sufficient distance to be detected but not
111

injurious could result in a momentary startle response or perhaps temporary

disorientation of a marine turtle.

Tactile Detection or Physical Discomfort

Data pertaining to the tactile perception of marine turtles from an explosive shock

wave are not available. It is reasonable to assume that marine turtle skin in soft tissue

areas, particularly areas around the eyes, mouth, external nares, and vent, are sensitive to

tactile stimulation. Based on studies conducted on human subjects, reports of tactile

perception associated with low-level or distant underwater detonations range from the

sensation of pressure, to “stings” of varying degree (moderate or strong) when exposed to

shock waves (Department of the Navy 2001). It is expected that marine turtles may also

experience similar sensations when exposed to low intensity or distant explosive shock

waves. However, the tactile perception of marine turtles to explosive shock waves within

this range of intensity would be of such brevity that it would be expected to cause at most

a momentary startle response. If exposed to stronger shock waves, strong tactile

responses (moderate to strong stings) would likely occur along with injuries to their

auditory system and other internal organs.

Injuries

Non-lethal Injuries

Non-lethal injuries include “minor” injuries to the turtle's auditory system and

certain internal organs. It should be noted that delayed complications arising from

individual or cumulative non-lethal injuries may ultimately result in the death of an

affected marine turtle.

The most sensitive organ to the primary effects of a blast wave is the auditory

apparatus (Office of the Surgeon General 1991). The rupture of the tympanic membrane,

or the tympanum in the case of marine turtles, while not necessarily a serious or

life-threatening injury, correlates to permanent hearing loss (Ketten 1995, 1998). No data

exist which correlate the sensitivity of the marine turtle tympanum and middle and inner

ear to trauma associated with shock waves associated with underwater explosions.

Other slight injuries include those to internal organs. These include slight lung

hemorrhage and contusions (defined as injury to tissue, usually without laceration [such

as bruising]), and hemorrhage of the gastrointestinal tract caused by excitation of radial

oscillations of small gas bubbles normally present in the intestine (Richmond et al. 1973;

Yelverton et al. 1973). Goertner (1982) developed a conservative model for calculating

the ranges for occurrence of these two types of internal organ injuries to marine mammals

when exposed to underwater explosion shock waves. This model by itself is probably not

applicable to marine turtles, as it is not known what degree of protection to internal

organs from shock waves is provided to marine turtles by their shell. The general

principals of the model, however, may be applicable. For lung hemorrhage, the Goertner

model considers lung volume as a function of animal weight (mass) and depth, and
112

considers shock wave duration and impulse tolerance also as a function of animal weight

and depth. Injuries to the gastrointestinal tract, however, could be related to the

magnitude of the peak shock wave pressure over the hydrostatic pressure, which,

according to the Goertner model, is independent of animal size and weight.

Overall, non-lethal injuries associated with underwater explosions, such as the

onset of lung hemorrhage and gastrointestinal tract contusion, are injuries from which a

marine turtle would be expected to recover on its own and would not be debilitating

(Department of the Navy 2001).

Lethal Injuries

Lethal Injuries to Internal Organs

Lethal injuries may result from massive trauma or combined trauma to internal

organs as a direct result of proximity of the affected turtle to the point(s) of detonation.

Extensive lung hemorrhage is an injury that all marine mammals or turtles would not be

expected to survive (Department of the Navy 2001). This discussion draws from

observations made on mammals subjected to underwater explosions. Gastrointestinal

tract injuries associated with the onset of extensive lung hemorrhage are shown to include

contusions with no ulcerations (defined as a break or disintegration of the surface tissue)

(Richmond et al. 1973). As the severity of the lung hemorrhage increases,

gastrointestinal tract injuries would be expected to include contusions with ulcerations

throughout the tract, ultimately including ruptures of the tract. Mortality associated with

these combined severe injuries is expected to be almost certain. As described in the

Department of the Navy (2001) analysis of impacts of underwater explosions on marine

mammals, the onset of extensive lung hemorrhage may also be used as a conservative

index for the onset of mortality of marine turtles of any size class.

Lethal Injuries from Shock Waves with High Peak Pressure

Exposure of animals to high peak pressure shock waves may result in concussive

brain damage, cranial, skeletal (or shell) fractures, hemorrhage, or massive inner ear

trauma (Ketten 1995). Depending upon the size of the animal (with smaller animals

being more susceptible), extremely high shock wave pressure impulse levels may or may

not be lethally injurious to the animal's internal organs. However, overall system shock

and significant external tissue damage as well as severe localized damage to the skeletal

system would be expected. These injuries, if not themselves fatal, would probably put

the animal at increased risk of predation, secondary infection, or disease (Department of

the Navy 2001).

6.2.2 Observations of Marine Turtles Injured or Killed by Underwater Explosives

Three unidentified marine turtles were unintentionally exposed to three

underwater detonation tests carried out by the Naval Coastal Systems Center off Panama

City, Florida in 1981 (O'Keeffe and Young 1984). Each test detonated a mid-water
113

charge equivalent of 1,200 lb (544 kg) of TNT in water of about 120 ft (37 m) depth.

Three unidentified marine turtles were noted subsequent to the detonations. The first, a

400 lb (182 kg) animal, was killed at a distance of 500 to 700 ft (152 to 213 m) from the

charge. The second, a 200 to 300 lb animal, received non-lethal, minor injuries at a range

of 1,200 ft (366 m) from the charge. The third, another 200 to 300 lb animal, was

apparently unaffected at a range of 2,000 ft (610 m) from the charge. Turtle depths at the

time of detonation are unknown. Assuming these animals were at a mid-water depth of

60 ft (18 m) at the time of the detonation, calculated shock wave pressures are 239, 161,

85, and 47 psi (35, 23, 12, and 7 kPa) at ranges of 500, 700, 1,200, and 2,000 ft

(152, 213, 366, and 610 m), respectively (Department of the Navy 2001). A summary of

the effects of underwater explosions on marine turtles, as reported by O’Keeffe and

Young (1984) and Klima et al. (1988), is presented in Table 6.4 (from Department of the

Navy 2001).

Evidence of the potential effects of explosive removal of offshore structures on

protected species first became apparent in March and April 1986 when 51 marine turtles,

primarily Kemp's ridley, and 41 bottlenose dolphin (Tursiops truncatus) were found dead

on Texas beaches shortly after the explosive removal of oil and gas structures in Texas

state waters of the Gulf of Mexico that involved 22 underwater explosions (Klima et al.

1988; NRC 1996). Because commercial shrimp trawling operations (a major cause of

marine turtle mortality) were at a very low level in the area, these mortalities were

attributed to explosions associated with these structure removals (though this was never

verified) (Klima et al. 1988).

In July 1986, an unidentified dead or injured turtle drifting in an inverted attitude

about 10 ft below the surface was sighted 1.5 hours after an explosive removal of an

offshore platform off Sabine Pass, Texas (Gitschlag and Renaud 1989).

After a 1987 explosive platform removal, two turtles (both loggerheads) that were

found stranded on nearby beaches were autopsied. One turtle showed no characteristics

consistent with explosive impacts. External inspection of the second turtle revealed a

bloated carcass with green-colored flesh and evidence of gas bubbles below the shell

scutes. Necropsy results showed lung hemorrhage, four ruptures of the right atrium, and

bloody fluid in the pericardial sac. Though lung hemorrhage is consistent with impacts

resulting from underwater explosions, this condition, along with ruptures in the heart,

may also have been the result of postmortem decomposition (Klima et al. 1988).

At a removal site of a caisson in 1991, a loggerhead with a fracture down the

length of its carapace surfaced within 1 minute of detonation (NRC 1996).

Two immature green turtles were killed when 20 lb (9.1 kg) of plastic explosives

(C-4) were detonated in open water (at distances of 100 to 150 ft [30.5 to 45.7 m] from

the charge) by a U.S. Navy Ordnance Disposal Team. Necropsy examinations revealed

extensive internal damages, particularly to the lungs (NRC 1996). Overall water depth,

charge depth, and turtle depths were not reported. Turtle body mass also was not

reported, although it is assumed to be small, considering the turtles were reported as of
Table 6.4

Underwater Explosion Effects on Marine Turtles Reported by O'Keeffe and Young (1984) and Klima 

(From: Department of the Navy 2001)

Charge Injuries

Weight

lbs (kg)

Charge

Depth

ft (m)

WaterDepth

ft (m)

Turtle

Weight

lbs (kg)

TurtleDepth

ft (m)

Range

ft (m)

Peak Pressure

psi (kPa) Immediate 1

O'Keeffe and Young (1984)

1,2001

 (544)

60

(18.3)

120

(36.6)

400

(181)

Unknown 500-700

(152-213)

258-178

(1,758-1,213)2 Mortal injury

1,2001

 (544)

60

(18.3)

120

(36.6)

200-300

(91-136)

Unknown 1,200

(366)

99

(675)2 Minor injury

1,2001

 (544)

60

(18.3)

120

(36.6)

200-300

(91-136)

Unknown 2,000

(610)

57

(388)2 None

Klima et al. (1988)

2032

(92)

14.8

(4.5)3

29.5

(9.5)

14.8

(6.7)

14.8

(4.5)

750

(229)

16.3

(111)3 Unconscious

Vasodilation flippers (lastcloacal linin

2032

(92)

14.8

(4.5)3

29.5

(9.5)

9.3

(4.2)

14.8

(4.5)

750

(229)

16.3

(111)3 Unconscious As above an

around eyes 

2032

(92)

14.8

(4.5)3

29.5

(9.5)

1.3

(0.6)

14.8

(4.5)

1,200

(366)

10.3

(70)3 Unconscious Appeared no

2032

(92)

14.8

(4.5)3

29.5

(9.5)

12.1

(5.5)

14.8

(4.5)

1,200

(366)

10.3

(70)3 Unconscious

Normal behaaround base 2-3 wks)

2032

(92)

14.8

(4.5)3

29.5

(9.5)

2.9

(1.3)

14.8

(4.5)

1,800

(549)

6.5

(44)3 None visible Appeared no

2032

(92)

14.8

(4.5)3

29.5

(9.5)

8.8

(4.0)

14.8

(4.5)

1,800

(549)

6.5

(44)3 None visible

Appeared novasodilation flippers (last
Table 6.4. Underwater Explosion Effects on Marine Turtles Reported by O'Keeffe and Young (1984) and Klima 

(From: Department of the Navy 2001) (continued).

Charge Injuries

Weight

lbs (kg)

Charge

Depth

ft (m)

WaterDepth

ft (m)

Turtle

Weight

lbs (kg)

TurtleDepth

ft (m)

Range

ft (m)

Peak Pressure

psi (kPa) Immediate 1

2032

(92)

14.8

(4.5)3

29.5

(9.5)

3.3

(1.5)

14.8

(4.5)

3,000

(915)

4.1

(28)3 None visible Appeared no

2032

(92)

14.8

(4.5)3

29.5

(9.5)

15.0

 (6.8)

14.8

(4.5)

3,000

(915)

4.1

(28)3 Unconscious

Appeared novasodilation flippers (last

1 TNT equivalent.2 Four 50.75-lb (23-kg) nitromethane charges buried 16.4 ft (5 m) below the mudline.3 Calculations for buried charges assumed a 2-lb (0.92-kg) TNT charge detonated “free-field” at mid-depth in the water column.
116

“immature” size class. In an open water environment, 20 lb (9.1 kg) of C-4 explosive, as

used in this event, would be expected to generate nominal peak pressures of 347 and

244 psi (2,394 and 1,684 kPa) at ranges of 100 and 150 ft (30.5 and 45.7 m), respectively

(Department of the Navy 2001).

Klima et al. (1988) placed four Kemp's ridley and four loggerhead turtles in cages

at four distances (750 ft [213 m], 1,200 ft [366 m], 1,800 ft [549 m] and 3,000 ft [915 m])

from an offshore platform scheduled for removal using explosive charges. The cages

were suspended at a depth of 15 ft (4.5 m) over a seafloor of 30 ft (9 m) depth prior to the

simultaneous detonation of four, 50.75 lb (23 kg) charges of nitromethane, placed inside

the platform's support pilings at a depth of 16 ft (5 m) below the seafloor (“mudline”).

The Kemps ridleys and loggerheads exposed at 750 ft and 1,200 ft, as well as one

loggerhead exposed at 3,000 ft, were rendered unconscious. The Kemps ridleys exposed

at 750 ft also sustained slight physical injury, showing an eversion of cloacal lining

through its vent. Remaining Kemps ridleys at more distant ranges were apparently

unharmed. All loggerheads displayed abnormal pink coloration of soft tissues around the

eyes and external nares, and at the base of the throat and flippers, reportedly caused by a

dilation of blood vessels. This condition persisted in these individuals for a period of 2 to

3 weeks.

Unfortunately, data collected by Klima et al. (1988) did not include concurrent

pressure measurements to estimate the magnitude and duration of the shockwave

received by the caged turtles. Peak shock wave pressures for buried charges such as

those used in this platform removal may be as low as 10% of expected free-field values

for non-buried charges (Connor 1990). Ranges and estimated pressures for this data set

were used to calculate an equivalent “non-buried” charge weight, using standard

similitude equations and weak shock theory (Gaspin 1983). From these data, a 2 lb

(0.92 kg) TNT charge detonated free-field would produce the shock wave pressures at the

ranges shown in Table 6.4. Since the water depth of this platform removal was

extremely shallow (30 ft [9 m]), multiple shock wave pulses and bulk cavitation resulting

from bottom- and surface-reflected shock waves could have impacted the turtles.

6.3 Marine Mammals

This section reviews and discusses the definition of impacts of underwater

explosions from the perspective of the NEPA and what constitutes a “significant” impact

on marine mammals. In addition, it addresses the potential for “takes” of marine

mammals as defined in the MMPA, as amended in 1994 (16 CFR §1431 et seq.). A

“take” is the equivalent of an impact under the MMPA.

The following section begins with a brief description of the hearing abilities of

marine mammals, followed by a discussion of the mechanisms by which shock waves

generated by underwater explosions affect marine mammals. The following types of

potential effects of explosives on marine mammals are then discussed:
117

 Changes in behavior and distribution of the animals (this definition is

currently under discussion for inclusion in the revised MMPA);

 Temporary reduction in hearing sensitivity evident as TTS;

 Permanent hearing impairment or damage to hearing organs evident as

permanent threshold shift (PTS); and

 Mortality or physical injury other than to hearing organs.

This discussion is followed by an analysis of the criteria used to determine level of

impact due to explosives and other pulsed noises, as accepted by NOAA-F (formerly

NMFS) within the context of the MMPA. The section concludes with sections on

mitigation and monitoring and data gaps and recommendations for research.

6.3.1 Zones of Influence

A series of zones of potential influence of generally decreasing size can be

defined for any particular sound. The zone within which the received level from an

explosive in at least one part of the frequency spectrum exceeds both the ambient level

and the absolute hearing threshold for a particular marine mammal species (at that

frequency) is often large. This is the zone of audibility. However, the zones within

which there is the potential for disturbance or displacement, and especially auditory

impairment or injury, will be much smaller (Figure 6.2). The maximum possible zone of

influence is the distance beyond which its received level falls substantially below the

ambient noise level or the hearing threshold in all frequency bands. Once the noise falls

substantially below ambient or below the hearing threshold, marine animals will not be

able to detect sound generated by the explosive. Ambient noise levels vary dramatically

over time and season and among geographic areas. Thus, the radius of the zone of

detection is also highly variable.

TTS is the lowest level of physical damage. Brief exposures to loud sounds can

temporarily increase the hearing threshold of an animal. This effect is temporary and

largely reversible. Prolonged exposure to continuous intense sounds can cause

permanent hearing damage (PTS). TTS is an important criterion of effect because it can

be and sometimes is used as a safety criterion: exposure to levels below the TTS

threshold will not cause physical damage, but may cause disturbance in some species.

Exposure to progressively higher levels causes increased risk of physical harm. In the

case of underwater explosives, these progress from mild recoverable damage to the lungs

and other organs to death.

6.3.2 Hearing in Marine Mammals

Hearing in Toothed Whales (Odontocetes)

Behavioral audiograms have been reported for a small number of species of

small- to moderate-sized odontocetes, and a partial audiogram is available for the Risso’s

dolphin (Nachtigall et al. 1995). Based on this research, it is evident that the odontocetes

tested to date hear sounds over a wide range of frequencies.
118

Figure 6.2. Schematic representation of the zones of potential influence of anthropogenic

sounds on marine mammals. Note that the vertical distances among the

different effects are not drawn to scale (Adapted from: Richardson et al.

1995).

These odontocetes hear best at frequencies of 20 kHz and above. At lower

frequencies, their hearing thresholds increase (deteriorate) with decreasing frequency.

Below the frequency range of optimum sensitivity, thresholds increase gradually with

decreasing frequency. However, estimated auditory thresholds for many species may be

inaccurate, and possibly too high, for frequencies below 1 to 10 kHz. The relatively

small sizes of the holding tanks used for most hearing tests cause confounding

complications, including echoes, standing waves, elevated noise levels, and nearby

pressure release boundaries (Cummings et al. 1975).

Hearing ability extends at least as low as 40 to 75 Hz in the bottlenose dolphin

(Figure 6.3), one of the species whose sensitivity at low frequencies has been reported in

detail (Johnson 1967). However, the hearing sensitivity of small-medium odontocetes at

these low frequencies seems quite poor. The thresholds of a Pacific white-sided dolphin

have also been shown to deteriorate at low frequencies (Figure 6.3; Tremel et al. 1998).

In contrast, the high-frequency hearing abilities of most small- to medium-sized

odontocetes are exceptionally good, and are related to these cetaceans’ use of

high-frequency sound for echolocation. The hearing range extends up to 80 to 150 kHz
119

Figure 6.3. Underwater audiograms of selected toothed whale species, showing the

minimum detectable sound level for tonal sounds at various frequencies.

Based on killer whale data of Szymanski et al. (1999), Pacific white-sided

dolphin data of Tremel et al. (1999), bottlenose dolphin data of Johnson

(1968), Risso’s dolphin data of Nachtigall et al. (1995, 1996), and harbour

porpoise data of Andersen (1970).

in at least some individuals of all of the species tested to date. New data from other killer

whales show upper frequency limits near 120 kHz, consistent with other small-medium

sized odontocetes (Szymanski et al. 1999).

Within the range of “middle” frequencies where odontocetes have their best

sensitivity, their hearing is very acute. When there was little background noise, the killer

whale tested by Hall and Johnson (1972) could detect a 15-kHz signal of ~30 dB, a very

low value. Except for the higher (~62 dB) threshold of the Pacific white-sided dolphin,

the minimum thresholds were ~42-55 dB for two additional odontocete species shown in

Figure 6.3. Overall, the frequencies at which these three species had best sensitivity

ranged from ~8 to 90 kHz (Figure 6.3). The best sensitivity of the Risso’s dolphin could

not be determined (Nachtigall et al. 1995).
120

The most sensitive frequency in the mean killer whale audiogram was 20 kHz

(36 dB), a frequency lower than that for other reported odontocetes; much spectral energy

has been reported for wild killer whale clicks at or near this frequency (Szymanski et al.

1999). Killer whales reliably responded to 100 kHz tones presented at 95 dB. Verboom

(2000) has suggested that this indicates that the absolute hearing threshold of larger

odontocetes is lower than that of the smaller species; this generalization has yet to be

demonstrated, given the lack of hearing data for many odontocete species.

The only information on the hearing abilities of sperm whales comes from a

single ABR1

 study of a sperm whale neonate that was stranded in Texas during

September 1989. Carder and Ridgway (1990) recorded neural responses to experimental

pulses presented at rates of 20 to 40 pulses per second. The calf’s ABR waves in

response to pulses ranging in peak frequency from 2.5 to 60 kHz appeared to be similar

to those reported for other mammals, and very similar to those observed in other

odontocetes (Carder and Ridgway 1990). The ABRs of highest amplitude were those to

frequencies of 5, 10, and 20 kHz, although there were weaker responses to 60 kHz tones.

Low-frequency hearing was not tested.

These data suggest that, at least for immature animals, sperm whales may have

medium- and high-frequency hearing abilities similar to other smaller odontocete species

tested to date. Whether this is true for adult sperm whales is unknown, and their absolute

hearing thresholds are also unknown. Sperm whales often react (by becoming silent)

when exposed to pulsed sounds at frequencies ranging from a few kHz up to at least

24 kHz (Richardson et al. 1995).

We are aware of no published data on the hearing abilities of Mesoplodon

(beaked) or Hyperoodon (bottlenose) odontocete species. Anecdotal accounts of the

northern bottlenose whale’s (H. ampullatus) response to sounds of low intensity (during

quiet periods) suggests that they are able to hear sounds of low amplitude (Hooker 1999).

Echolocation clicks with components from 2 to 24 kHz were recorded while bottlenose

whales were diving in a deep canyon on the NW Atlantic continental shelf (Hooker

1999), and clicks of lower frequency were heard while these whales were at the surface.

While this suggests that this species can hear sounds ranging in frequency from 2 to

24 kHz, the recording system was unable to sample frequencies above 35 kHz (Hooker

1999). Further studies are required to determine the full range of bottlenose and beaked

whale vocalizations and to measure the relationship between sound frequency and

sensitivity for this, and other, large odontocetes.

Hearing Abilities of Baleen Whales (Mysticetes)

Due to their large size and the consequent difficulties in maintaining them in

captivity, the hearing abilities of mysticete whales have not been studied directly using

behavioral or AEP methods.

 

1 Electrical brain activity is detected using electrodes attached harmlessly to the skin of the whale as

sounds are played to the marine mammal; this is an auditory evoked potential (AEP) method.
121

The available data on low-frequency hearing suggest that in odontocetes and

pinnipeds, as in terrestrial mammals, sensitivity deteriorates with decreasing frequency

below the “best” frequency. This is probably, in part, an adaptation to the typically high

levels of natural underwater noise at low frequencies. However, it is not known how

closely mysticetes follow this trend. They are known to emit low-frequency sounds.

That, plus the anatomy of their auditory organs (Ketten 2000), suggests that mysticete

whales have good low-frequency hearing.

Behavioral evidence indicates that mysticetes hear very well at frequencies below

1 kHz (Richardson et al. 1995). Mysticete whales have also been observed to react to

sonar sounds at 3.1 kHz and other sources centered at 4 kHz. Some mysticetes react to

pinger sounds up to 28 kHz, but not to pingers or sonars emitting sounds at 36 kHz or

above (Watkins 1986).

Some mysticetes produce sounds at frequencies up to 8 kHz, although their calls

are predominantly at low frequencies, mainly below 1 kHz (see Chapter 7 in Richardson

et al. 1995). Based on this, plus the aforementioned anatomical evidence, it is presumed

that their hearing abilities are good at low frequencies. The auditory system of mysticete

whales is almost certainly more sensitive to low-frequency sounds than is the auditory

system of the small- to moderate-sized odontocete whales. Mysticetes are known to

detect the low-frequency sound pulses emitted by seismic airguns and change their

direction of movement (e.g., Richardson et al. 1986; Miller et al. 1999; McCauley et al.

2000) or change their calling behavior (Greene et al. 1999).

Based on this indirect field and anatomical evidence, we can probably assume that

mysticete whale hearing is similar at frequencies ranging from <1 to 8 kHz, and then

deteriorates with increasing frequency. Ambient noise energy in the ocean is higher at

low frequencies than at mid-frequencies. At frequencies in the 1 to 8 kHz range, ambient

noise levels occurring under the quietest natural conditions (and in the absence of

manmade sound) are rarely less than 60 dB on a 1/3rd octave basis, i.e., in bands roughly

approximating the filter bandwidth of the mammalian ear (Richardson et al. 1995). It is

unlikely that mammals would have evolved a hearing system able to hear sounds much

lower than the weakest masking noise that would ever be encountered. We might

therefore expect that the hearing threshold for mysticete whales is about 50 dB at their

best frequencies. Sensitivity probably deteriorates at higher frequencies. It probably also

deteriorates slowly with diminishing frequency below 1 kHz, in parallel with the lowest

levels of natural ambient noise (on a 1/3rd octave basis).

6.3.3 Mechanisms of Injury

High explosive detonations have a velocity of detonation of 5,000 to 10,000 m per

second (Urick 1975; Parrott 1991; Demarchi et al. 1998). Because of this, they have very

short rise times of about 20 microseconds and short pulse durations of about 0.2 to

0.5 milliseconds. After the initial positive shock pulse that causes pressure to increase,

pressure falls below ambient pressure and then rises to a second maximum known as the

first bubble pulse. The time between the shock and the first bubble pulse is 0.17 to
122

0.5 seconds, depending on the size of the explosive (Demarchi et al. 1998). Effective

broadband source levels for high explosive charges of 0.5 to 20 kg are on the order of

267 to 280 dB re 1 μPa at nominal 1-m distance (Richardson et al. 1995).

There are two mechanisms of injury. The very rapid rise time of the shock wave

causes much damage. The sharp rise in pressure is followed by a negative pressure wave

generated by the collapsing bubble. A series of decreasing positive and negative pressure

pulses follow the main pulse. Marine mammals are designed to withstand changes in

pressure. A human can dive to a depth of 30 m and ascend to the surface again in

10 minutes. However, an instantaneous change in depth from 0 to 30 m and back to 0 m

would have catastrophic effects on humans and marine mammals.

Shock waves can cause minor or severe injury or mortality, depending on the

intensity of the shock wave and size and depth of the animal (Yelverton et al. 1973; Craig

and Hearn 1998; Craig 2001). The most severe damage takes place at boundaries

between tissues of different density. Different velocities are imparted to tissues of

different densities, and this can lead to their physical disruption. Blast effects are greatest

at the gas-liquid interface (Landsberg 2000). Gas-containing organs, particularly the

lungs and gastrointestinal tract, are especially susceptible (Yelverton et al. 1973;

Hill 1978; Goertner 1982). Lung injuries, including laceration and rupture of the alveoli

and blood vessels, can lead to hemorrhage, creation of air embolisms, and breathing

difficulties. In addition, gas-containing organs including the nasal sacs, larynx, pharynx,

trachea, and lungs may be damaged by compression/expansion caused by the oscillations

of the blast gas bubble (Reidenberg and Laitman 2003).

Intestinal walls can bruise or rupture, with subsequent hemorrhage and escape of

gut contents into the body cavity. Less severe gastrointestinal tract injuries include

contusions, slight hemorrhaging, and petichia (Yelverton et al. 1973).

Ketten et al. (2003) and Reidenberg and Laitman (2003) exposed dead marine

mammals to underwater blasts. Damage was consistent with what would be expected in

live animals and included apparent hemorrhages at the blubber-muscle interface and in

gas-containing organs and the gastrointestinal tract; ruptures of the liver and spleen; and

contusions of the kidney. The blubber, melon, and jaw fats have distinct damage patterns

(Ketten et al. 2003). The density and, hence, sound speed velocity in these tissues are

different from those of adjoining tissues. In humans, compression of the thorax and

abdomen by the shock wave would cause rapid increase in venous pressure in the brain,

leading to rupture of small blood vessels, petechial hemorrhage, and oedema

(Landsberg 2000). Compression also appears to cause air to enter tissues adjacent to air

spaces in dead marine mammals exposed to explosives (Reidenberg and Laitman 2003).

The rapid decompression during the negative bubble pulse could cause air embolism in

humans (Landsberg 2000).

Because they are the most sensitive to pressure, the ears are the organs most

sensitive to injury (Ketten 2000). Ketten (1995, 1998, 2000) has described the hearing

organs of marine mammals. The external ears are occluded and end in a blind pouch that
123

does not contact the middle ear. In odontocetes, sound is transmitted by fatty sound

channels and bone in the jaw. The fluid-filled middle ear contains the tympanic

membrane and the ossicle bones. The tympanic membrane has no direct contact with the

water. The inner ear contains the spiraled cochlea and balance organs. Hair cells in the

cochlea transmit sound to the auditory nerves. The basilar membrane is a main part of

the cochlea. Its shape, stiffness, thickness and mass determine an animal’s hearing

abilities. Severe damage to the ears includes tympanic membrane rupture, fracture of the

ossicles, damage to the cochlea, hemorrhage, and cerebrospinal fluid leakage into the

middle ear. Moderate injury implies partial loss of hearing due to tympanic membrane

rupture and blood in the middle ear. Permanent hearing loss also can occur when the hair

cells are damaged by loud noises caused by one very loud event, prolonged exposure to a

loud noise, or chronic exposure to noise. The latter type of injury was common among

factory workers and soldiers, especially artillery men, prior to the advent of hearing

protection guidelines and mandatory use of hearing protection.

Single airguns used in seismic exploration produce pulses with rise times slower

that those of high explosives. Rise time for airgun pulses are on the order of

1 millisecond, the initial positive pulse is of about 2 milliseconds duration, and the

following pulse is about 3 to 5 milliseconds in duration (Parrott 1991). In addition,

during seismic exploration, airguns are fired several times per minute for periods of days

or weeks. There is a great deal of literature on the effects of shock waves produced by

airguns used for seismic exploration on marine mammals and other marine life.

However, because the nature of shock waves produced by high explosives and airguns is

very different, much of the literature on effects of seismic pulses cannot be used to

estimate physical effects of explosives on marine mammals.

6.3.4 Review of the Documented Effects of Explosives on Marine Mammals

There is a great deal of literature on the potential and some on the observed

effects of explosives on marine mammals, but very little quantitative data on the impulses

needed to cause various kinds of effects, and those that do exist are based on experiments

with terrestrial animals. Most of the data are qualitative in nature. This section will deal

with documented cases of effects of underwater explosions on marine mammals, and the

following section will deal with blast injury models that have been developed to predict

potential impacts.

Effects on Behavior and Distribution

Behavioral reactions of marine mammals to a sound are difficult to predict.

Reactions to sound, if any, depend on species, state of maturity, experience, current

activity, reproductive state, time of day, weather, and many other factors. If a marine

mammal does react to an underwater sound by changing its behavior or moving a small

distance, the impacts of the change may not be significant to the individual, the stock, or

the species as a whole. On the other hand, if a sound source displaces marine mammals

from an important feeding or breeding area for a prolonged period, impacts on the

animals could be significant.
124

There is relatively little information on effects of explosives on marine mammal

behavior. Therefore, we also have included information on effects of seismic exploration

on behavior, recognizing that the nature of shock waves produced by high explosives and

airguns is very different.

Gray whales exposed to noise from explosives “were seemingly unaffected and in

fact were not even frightened from the area” (Fitch and Young 1948); no other

information was given. Payne and McVay (1971), studying humpback whales, stated

that “loud sounds in the ocean, for example dynamite blasts, do not seem to affect the

whale's songs.” Payne (1970) presented a recording of a humpback that continued to sing

through the noise from two distant explosions. Lien et al. (1993) found that humpbacks

remained in an area where there were repeated large underwater detonations; whales that

were observed directly during detonations apparently did not show obvious behavioral

reactions. Some of these humpbacks may have been close enough to the blast site to

suffer hearing damage or other physical injuries (Ketten et al. 1993; Ketten 1995).

During the 1950’s, small explosive charges were dropped into an Alaskan river in

attempts to scare belugas away from salmon. Success was limited (Fish and Vania 1971;

Frost et al. 1984). Small explosive charges were “not always effective” in moving

bottlenose dolphins away from sites in the Gulf of Mexico where larger demolition blasts

were about to occur (Klima et al. 1988). Odontocetes may be attracted to fishes killed by

explosions, and thus attracted rather than repelled by “scare” charges. Hence, scare

charges are now not used in the Gulf of Mexico platform removal program (G.R.

Gitschlag pers. comm. 1994, in Richardson et al. 1995). Captive false killer whales

showed no obvious reaction to single noise pulses from small (10 g) charges; the received

level was ~185 dB re 1 μPa (Akamatsu et al. 1993).

“Seal bombs” have a source level of about 190 dB re 1 μPa (Jefferson and

Curry 1994). Jefferson and Curry (1994) reviewed studies of the effects of these on

marine mammals and found that they were largely ineffective. They did not keep harbor

seals and several species of fur seal out of an area, especially when fishes were in that

area. The seals either habituated or returned. Off Alaska, seal bombs, blasting caps, and

even dynamite were ineffective in keeping killer whales away from longlines.

Explosives have also been unsuccessful in keeping bottlenose dolphins off Africa, Dall’s

porpoise in the North Pacific, and dolphins in the Mediterranean Sea away from fishing

gear (Jefferson and Curry 1994).

Seal bombs were, until recently, widely used to influence the movements of the

dolphins around which purse-seine nets are set during tuna fishing operations in the eastern

Pacific Ocean (Cassano et al. 1990; Myrick et al. 1990a,b). The charges were thrown

within meters of the dolphins in attempts to divert them onto a different heading. One

method of fishing involved the use of seal bombs thrown from helicopters and speedboats

at and around schools of dolphins (Glass 1989). The dolphins would slow down and

become confused. They would then form a protective school. As the mile long net was
125

being set, seal bombs were used to keep dolphins and tuna from escaping through the open

side. U.S. regulations now prohibit the use of seal bombs in the tuna-dolphin fishery.

Finneran et al. (2000) exposed trained captive bottlenose dolphins and beluga

whales to single simulated sounds of distant explosions. Broadband received sound

levels were 170 to 221 dB re 1 μPa (p-p; 155 to 206 dB rms). Maximum spectral density

was about 102 to 142 dB re 1 μPa2

/Hz at a 6.1 Hz bandwidth. Pulse durations were 5.4 to

13 ms. Behavioral alterations began at 196 to 209 dB (p-p; 181 to 194 dB rms; 120 to

127dB re 1 μPa2

/Hz). Although pulse durations for the two studies were different, the

sound levels required to induce disturbance appear to have been similar to those found by

Ridgway et al. (1997) and Schlundt et al. (2000). Behavioral alterations were departures

from trained behaviors to the stimuli and included swimming around the enclosure rather

than travelling directly between stations, vocalizing, refusing to return to a station, and

remaining on a station.

More specific information about the reactions of some baleen and odontocete

whales to low-frequency noise pulses has been obtained by observing their responses to

pulses from airguns and other non-explosive methods of marine seismic exploration.

Bowhead whales on their summering grounds in the Beaufort Sea (Richardson et al.

1986), migrating gray whales off California (Malme et al. 1983, 1984), and migrating or

lingering humpback whales off Western Australia (McCauley et al. 1998, 2000) all

showed clear avoidance reactions to seismic sounds at received levels of about 160 to

170 dB re 1 μPa (rms) and, in some cases, somewhat lower levels. Humpback whales

showed avoidance at a mean received sound level of 140 dB re 1μPa rms. About 50% of

feeding gray whales will cease feeding at an average peak pressure level of 173 dB

(Malme et al. 1988), and about 50% of migrating gray whales will avoid a seismic source

at the about the same average received sound levels (Malme and Miles 1985).

Behavioral changes have sometimes been evident at somewhat lower received

levels. Migrating bowheads avoided an active seismic survey boat at received sound of

116 to 135 dB, but avoidance did not persist for more than 12 to 24 h after cessation of

operations (Miller et al. 1999; Richardson et al. 1999). These avoidance reactions

occurred at much lower average received levels than the average of 160 to 170 dB needed

to elicit responses on their summering grounds.

There is some recent evidence that sperm whales may cease calling when exposed

to weak noise pulses from extremely distant (>300 km) seismic exploration (Bowles et al.

1994) and that they may, perhaps, move away from a seismic vessel (Mate et al. 1994).

The observed avoidance reactions involved movement away from feeding locations or

statistically significant deviations in the whales’ direction of swimming and/or migration

corridor as they approached or passed the sound sources. In the case of the migrating

whales, the observed changes in behavior appeared to be of little or no biological

consequence to the animals—they simply avoided the sound source by displacing their

migration route to varying degrees, but within the natural boundaries of the migration

corridors. As noted above, seismic pulses are usually emitted several times per minute

for days or weeks at a time.
126

Common dolphins avoid the localized area around active seismic vessels and may

tolerate sounds at distances of 1 km or more from the array (Goold 1996; Goold and

Fish 1998). The proportion of all small cetaceans sighted during seismic shooting in

UK waters was reduced within given ranges of large arrays (Stone 2003). There was no

difference in the sighting rates of large cetaceans. Behavior of whales was different

between periods when airguns were active and when they were not shooting

(Stone 2003). When guns were active, there was less bow-riding, fewer approaches to

the vessel, and fewer instances of swimming alongside, following, or close ahead of the

vessel and more alterations of course away from the vessel. In some instances, reaction

to the airgun sounds was species-specific. There also was less evidence of feeding

activity when airguns were operating. Behavior during a soft start or ramp up was about

midway between fully operational and no guns firing. As in the case of baleen whales,

avoidance was temporary (Stone 2003).

Sperm whales apparently reacted to seismic sounds at a distance of about 20 km

where received sound levels were 146 dB re 1 μPa (p-p) or 124 dB re1 μPa2 (Madsen et

al. 2002).

In general, there seems to be a great deal of variability in the reactions to low

frequency pulsed sounds among species. A given species may react differently

depending on the time of year and their activity. Single or a few pulses may not have

much of an evident behavioral effect, and single very loud pulses may have no effect on

some species when they are feeding. Effects of single loud pulses may have only a

transitory affect on behavior.

Temporary Threshold Shift (TTS)

TTS is the mildest form of hearing damage that occurs during exposure to a

strong sound (Kryter 1985). TTS is the process whereby exposure to a strong sound

results in a non-permanent elevation of the minimum hearing sensitivity threshold

(Kryter 1985). TTS can last from minutes or hours to days. The magnitude of TTS

depends on the level and duration of noise exposure, among other considerations

(Ward 1997). While experiencing TTS, a sound must be louder to be heard. For sound

exposures at or somewhat above the TTS threshold, hearing sensitivity recovers rapidly

after exposure to the noise ends.

Only a few data on sound levels and durations necessary to elicit mild TTS have

been obtained for marine mammals. TTS studies in humans and terrestrial mammals

provide helpful information, but it is unclear to what extent these data can be extrapolated

to marine mammals.

Exposure to a sound can be expressed in terms of energy expressed in terms of

dB re 1 μPa2

-s. Energy considers the intensity and duration of a sound. A sound of low

intensity and long duration can contain the same amount of energy as a short sound of
127

high intensity. Different researchers used different exposure times sound intensities, so

the TTS data discussed below have been standardized in terms of energy.

Ridgway et al. (1997) exposed bottlenose dolphins exposed to 1-sec tones.

Schlundt et al. (2000) expanded on this study to measure masked underwater hearing

thresholds in five bottlenose dolphins and two beluga whales before and immediately

after exposure to intense 1-sec tones at 0.4, 3, 10, 20, and 75 kHz. TTSs of 6 dB or larger

were observed after exposure to between 192 and 201 dB re 1 μPa. The exceptions

occurred at 75 kHz, where one dolphin exhibited TTS after exposure at 182 dB re 1 μPa

and the other dolphin did not show any shift after exposure to maximum levels of 193 dB

re 1 μPa, and at 0.4 kHz, where no subjects exhibited shifts upon exposure to levels up to

193 dB re 1 μPa. At the conclusion of the study, all thresholds had returned to baseline

values, so there was no evidence of PTS.

Au et al. (1999) exposed captive bottlenose dolphins to 30 to 50 minutes of

octave-band continuous noise in the 5 to 10 kHz band. Hearing was not affected when

the noise level was 171 dB re 1 μPa (energy flux density of 205 dB re 1 μPa2

-s).

Moderately strong TTS of 12 to 18 dB was obtained when the noise level was 179 dB re

1 μPa (energy flux density 213 dB re 1 μPa2-s).

Kastak et al. (1999) induced mild TTS in California sea lions, harbor seals, and

northern elephant seals by exposing them to underwater octave-band noise at frequencies

in the 100 to 2,000 Hz range for 20 to 22 minutes. TTS of 4.8 dB became evident when

the received levels were 161 to 196 dB re 1 μPa2-s. Exposure was not continuous

because the animals rose to the surface to breathe. All recovered to baseline hearing

sensitivity within 24 hr of exposure

Nachtigall et al. (2003) exposed bottlenose dolphins to noise with peak amplitude

at 4 to 11 kHz for 55 minutes. The test animals experienced an average TTS of 11 dB on

exposure to 179 dB re 1 μPa (213 dB re 1 μPa2-s). Recovery from the TTS was complete

after 45 minutes.

Finneran et al. (2000) exposed two bottlenose dolphins and a beluga whale to

broadband sounds resembling that of distant underwater explosions. The intensity and

duration of the pulses were not sufficient to cause TTS, defined as a threshold shift equal

to or greater to 6 dB. A bottlenose dolphin showed a TS of 5.6 dB when exposed to

energy of 177 dB re 1 μPa2

-s, and a white whale showed TS of 4 dB after exposure to

energy of 179 dB. The waveform produced by the piezoelectric transducers lacked

energy in the lower part of the spectrum, which contains most of the energy generated by

explosives. Finneran et al. (2002) exposed a bottlenose dolphin and a white whale to

sounds from a seismic water gun that produced most of its energy at frequencies below

1 kHz but contained substantial energy up to 40 kHz and above. The white whale

sustained TTS of 7 dB at a received energy level of 186 dB re 1 μPa2

-s. Most of the

animals exposed in these experiments did not sustain TTS. Results of these studies are

summarized in Figure 6.4.
128

TTS may be related to several variables, including

 Intensity of sound;

 Pulse duration;

 Amount of TS; and perhaps

 Recovery time.

Figure 6.4 shows exposure in terms of energy and duration of the exposure, but does not

consider amount of TTS. Thus some of the variability shown in Figure 6.4 can be

explained by the differential amount of TS that was experienced by the test animals. On

average, the animals tested by Schlundt experienced TTS of 9.5 dB. TS experienced by

Finneran et al.’s (2000, 2002) and Kastak et al.’s (1999) animals was lower than 6 dB.

The dolphin in Au et al.’s (1999) test experienced >12 dB of TTS.

Figure 6.4. Energy levels (dB re 1 μPa2

-s) of underwater sound that have resulted in

temporary threshold shift in odontocetes (red squares) and pinnipeds (blue

rectangle). Data are expressed as energy (dB re 1 μPa2

-s). Data from

Au et al. (1999), Kastak et al. (1999), Schlundt et al. (2000), Finneran et al.

(2000, 2002), and Nachtigall (2003). Also plotted are the 5 and 3 dB

exchange rates converted to energy. Energy values were estimated as per

Finneran et al. (2000).

150

160

170

180

190

200

210

220

0.0

01

0.0

1

0.1 1 10 100 100

0

100

00

Time (s)

Energy (dB re 1μPa2.s)

Au et al. (1999)

Kastak et al.

(1999) Pinnipeds

Schlundt et al. (2000)

Finneran et al.

(2000, 2002)

Nachtigall et al.

(2001)

5 dB doubling

3 dB doubling
129

There are two options for allowing for the effect of pulse duration:

 The equal energy or 3 dB exchange rate, where the rms sound pressure level

required to cause TTS increases by 3 dB for every doubling of the pulse

duration; and

 The more conservative 5 dB exchange rate, where the rms sound pressure

level required to cause TTS increases by 5 dB for every doubling of the pulse

duration.

Figure 6.5 shows the relationship between average energy to which the odontocetes

tested in the experiments described above were exposed and the average amount of TS

they experienced. There appears to be a linear relationship between the amount of TS

and the amount of energy to which an odontocete is exposed.

Figure 6.5. Average threshold shift experienced by and average amount of energy to

which bottlenose dolphins and white whales were exposed in the experiments

described in the text.

Allowing for the differential in TS experienced by the animals shown in

Figure 6.5, the data in Figure 6.4 seem to fit the 3 dB exchange rate (equal energy). For

a single exposure, an equal amount of energy is required to cause TTS regardless of the

duration of the exposure. Frequency may also be unimportant. These results are

consistent with evidence from terrestrial mammals in that TTS thresholds in the dolphins

were not related strongly to the frequency of the sound. TTS has been defined as a TS of

6 dB or more (Finneran et al. 2000). In the tests described above, this amount of TTS

was associated with an energy level of about 184 dB re 1 μPa2

-s (Figure 6.4). Finneran

(2003) concluded that data are few and caution needs to be used when interpreting them

and applying them to impulsive sounds with high peak pressures or different waveforms.

Two criteria should be used.

4

6

8

10

12

14

16

175 180 185 190 195 200 205 210 215

Energy (dB re I μPa2

- s)

Amount of TTS (dB)
130

The Department of the Navy (2001), Helweg et al. (1998), and Sigurdson et al.

(2001) estimated that TTS would occur under two different criteria, one based on energy

and the other on peak pressure. Helweg et al. (1998) and Sigurdson et al. (2001) only had

access to the Ridgway et al. (1997) data that were also used by Schlundt and not the

remainder of the TTS data mentioned above. Those early data showed that average TTS

of 9.5 dB was induced by 1-s tones at 192 to 201 dB rms. They used 192 dB rms as a

conservative estimate for TTS and estimated the energy that induced TTS for brief tonal

signals to be 182 dB re 1 μPa2

-s at a conservative pulse duration of 100 ms (Sigurdson et

al. 2001). The energy was reference to 1/3 octave bands because human and dolphin

cochlea can be modeled as a bank of 1/3 octave filters (Sigurdson et al. 2001). TTS was

assumed to be induced if the received energy in any 1/3 octave band was greater than

182 dB re 1 μPa2-s. Total broadband energy in all 1/3 octave bands would be about

193 dB re 1 μPa2-s.

The new data show that TTS induced by broadband noise and noise from tones,

including low frequency noise, fall within the same range (Figures 6.4 and 6.5) and that

TTS of 9.5 dB is induced at 195 dB re 1 μPa 2

-s (Figure 6.5). Broadband received levels

at 200 m from a 3 kg charge would be 195 dB re1 μPa 2

-s and 184 dB in the 1/3 octave

band centered at 400 Hz (the octave band containing the highest energy). Thus the new

data do not contradict the criteria used by Department of the Navy (2001) and accepted

by NMFS (2001).

Assuming that the time of arrival of the surface cutoff wave for a 3 kg blast at

200 m distance is 14 ms (computed according to Yelverton 1981), received broadband

total energy would be about 195 dB re 1 μPa 2

-s. This would equate to about

213.5 dB rms and 216.5 dB peak pressure or about 9.7 psi peak pressure.

The second criteria for TTS used by the Department of the Navy (2001) and

accepted by NMFS (2001) is that TTS is deemed to occur at received peak sound

pressure of 12 psi. This criteria is based on a model created by Ketten (1995), which she

derived through examination of ear trauma studies and models of the effect of blast over

pressure on the structure of the ear. The 12 psi criteria was also accepted by NMFS

(2001). For these explosions, the distance to each criterion was to be computed and the

most conservative was to be used.

In the Seawolf and DDG 81 ship shock test EISs (Department of the Navy 1998,

2001), harassment was defined as the TTS criterion, which is the safe outer limit for

recoverable auditory damage. TTS was assumed to be induced if energy was greater than

182 dB re 1 μPa2

-s within any 1/3 octave band or peak pressure exceeded 12 psi. Their

procedure for calculating critical distances for TTS was as follows:

 Calculate the energy density spectrum for the waveform;

 Note the peak pressure in the waveform and compare it to the 12 psi criterion;

 Integrate the spectrum in 1/3 octave bands;
131

 Determine if the energy density in any 1/3 octave band exceeds

182 dB re 1 μPa 2-s (considering frequency ranges of 100 Hz for toothed

whales and 10 Hz for baleen whales); and

 Determine the shortest distance at which either of these energy criteria is

exceeded for various sound speed profiles.

Multiple Exposures

A practical approach to assessing impacts of multiple exposures might be the

“equal-energy” criterion of NIOSH (1998). This is conservative in the sense that the

assumed impact definition does not account for recovery. It has the great advantage of

readily allowing for the varying energy content of pulses received at different times,

distances, and positions relative to the axis of a sonar beam. It also provides a way to

deal with an animal simultaneously exposed to pulses from more than one source or to

continuous sounds and pulsed sounds at the same time.

Exposure to pulsed sounds with a low duty cycle is expected to result in a reduced

TTS threshold relative to a continuous exposure because, at least in humans, there may be

some recovery between pulses (Ward 1997). The relationship between number of pulses

and reduction in TTS threshold is unlikely to be linear or simple. For intermittent sounds

of varying intensity, TTS in humans is not a constant function of total energy received,

but is related to the temporal distribution of the received energy (Ward 1997). The

reduction in damage is greater with short pulses and long inter-pulse intervals. The

duration of the pulse appears to be more important than the inter-pulse interval in

determining the amount of damage sustained (Ward 1991, 1997). Schlundt et al. (2000)

found that recovery from TTS of 6 to 17 dB induced by a single 1 second pulse occurred

after about 5 to 16 min. In terrestrial animals, recovery from large amounts of TTS takes

hours or days (Ward 1970). In terrestrial animals, if the inter-pulse interval is short, the

amount of TTS induced is a linear function of the number of pulses (combined total time

of the pulses (Ward et al. 1961; Ward 1997). There are too few data to determine a

metric for correcting for number of pulses, duration of pulse, and inter-pulse interval in

humans (Ward 1991; NIOSH 1998). The 3 dB equivalent energy correction is a

conservative way of accounting for multiple pulses (Ward 1991). Thus, when assessing

TTS for animals potentially exposed to multiple shots, it would be prudent to add the

energy from all shots. Thus, a 25 kg charge would result in received energy levels at

100 m distance of 204 dB re 1 μPa 2

-s. Four such shots would result in received energy

levels of 210 dB re 1 μPa 2

-s [204 dB re 1 μPa 2-s + 10Log(4 shots)].

Permanent Threshold Shift and Hearing Damage (PTS)

When there is physical damage to the sound receptors in the ear there can be total

or partial deafness, while in other cases, the animal is unable to hear sounds at specific

frequency ranges. Physical damage to a marine mammal’s hearing apparatus can occur if

it is exposed to sound impulses that have high peak pressures, especially if they have very

short rise times. Such damage can result in permanent decrease in functional sensitivity
132

of the hearing system at some or all frequencies. This permanent increase in the

threshold above which the mammal can detect sound is termed PTS.

Single or occasional occurrences of mild TTS do not cause permanent auditory

damage in terrestrial mammals, and presumably do not do so in marine mammals. Very

prolonged exposure to noise strong enough to elicit TTS, or shorter-term exposure to

noise levels well above the TTS threshold, can cause PTS. Sound impulse duration, peak

amplitude, and rise time are the main factors thought to determine the onset and extent of

PTS. Based on existing data, Ketten (1995) has noted that the criteria for differentiating

the sound pressure levels that result in PTS (or TTS) are location- and species-specific.

PTS effects may also be influenced strongly by the health of the receiver’s ear.

At least in terrestrial mammals, the received sound level from a single noise

exposure must be far above the TTS threshold for there to be any risk of PTS, i.e.,

permanent hearing damage (Kryter 1985, 1994; Richardson et al. 1995). Relationships

between TTS and PTS thresholds have not been studied in marine mammals but are

assumed to be similar to those in humans and other terrestrial mammals.

Lien et al. (1993) found that humpback whales remained in an area where there

were repeated large underwater detonations. Two beached humpbacks had damaged

auditory organs, consistent with the types of damage caused by explosions (Ketten et al.

1993). It is not known how close they may have been to the explosions.

Bohne et al. (1985, 1986) found that the inner ears of 5 of 11 Weddell seals that

they examined showed evidence of previous damage. The type of damage observed was

consistent with exposure to high noise levels. Numerous explosive charges had been

detonated in the area the previous summer. There was suspicion but no proof that the

auditory damage was caused by those explosions.

In humans, PTS can be induced by a single short exposure at very high level or by

repeated longer exposures at moderate level (Ward 1997). There is no clear relationship

between PTS, TTS, and cochlear damage (NIOSH 1998). In humans, hearing loss with

increasing age is an accumulation of PTS and TTS over time (Ward 1997).

Morphological studies of the ears of older dolphins showed the same kinds of changes

that were associated with hearing loss in humans (Gisner 1998). Sharp rise times, such as

those produced by explosions, induce PTS at lower intensities than do other types of

sounds (Gisner 1998).

Damage to hair cells in the ear has been associated with hearing loss in fishes

(Gisner 1998; McCauley et al. 2000). In fishes, there is some regeneration of hair cells

over time, but it is unknown whether this leads to complete recovery of hearing

capabilities.

Ketten (1995) estimated that >50% PTS would occur at peak pressures of 237 to

248 dB re 1 μPa and TTS at peak pressures of 211 to 220 dB for explosives (units

converted by Cavanagh 2000). To avoid physical injury from explosives, Ketten (1995)
133

recommends a safe peak pressure level of 100 psi (237 dB re 1 μPa ≈

212 dB re 1 μPa2

-s). PTS will be assumed to occur at a received sound level of 30 dB

greater than that inducing TTS. Studies of TTS in terrestrial mammals have shown TTSs

of 40 dB and larger are associated with the loss of sensory hair cells (e.g., Ahroon et al.

1996). Animals can recover from smaller amounts of TTS.

Mortality or Physical Injury

Intense shock waves, because of their high peak pressures and rapid changes in

pressure, can cause mortality or severe damage to marine mammals. The most severe

damage takes place at boundaries between tissues of different density. Different

velocities are imparted to tissues of different densities, and this can lead to their physical

disruption. Gas-containing organs, particularly the lungs and gastrointestinal tract, are

especially susceptible (Yelverton et al. 1973; Hill 1978; Goertner 1982).

Only a few published accounts are available pertinent to non-auditory damage to

marine mammals exposed to blast. These accounts, while providing no information

about the strengths of blasts that did and did not cause damage, include the following:

 Fitch and Young (1948) reported that, on at least three occasions, California

sea lions were killed during seismic exploration using high explosives. In

contrast, gray whales “in the region of a blast were seemingly unaffected.”

Unfortunately, the distances from the explosives, numbers of mammals

affected and unaffected, and the sizes and positions of the charges were not

stated, and necropsies apparently were not done. Charges in use during the

study usually consisted of either 18 to 36 kg of high explosive detonated “a

few feet” underwater, or 9 kg detonated in the bottom sediment.

 Reiter (1981) reported without further details that there was evidence of

northern fur seals and birds killed from concussion in the immediate area of

demolition when a grounded ship was broken up by about 454 kg of

explosive. Again, numbers and distances are unknown.

 Northern fur seals have been killed by an 11.4-kg dynamite charge exploded

23 m away (H.F. Hanson 1954; cited in Wright 1982).

 Chinese river dolphins, Irrawaddy dolphins, finless porpoises, and dugongs

have been killed by explosions, usually involving the use of sticks of

dynamite to catch fishes (Leatherwood and Reeves 1989; Zhou and Xingduan

1991; Baird et al. 1994).

 In the Gulf of Mexico, dolphins are often seen near obsolete oil industry

platforms scheduled for explosive removal (Klima et al. 1988). Demolition

blasts are delayed when dolphins are within 915 m, and no confirmed blast

injuries or mortality have been reported.

The auditory effects of the “seal bombs” thrown near dolphins during some tuna

fishing have not been reported. An M-80 containing 3 g of explosive killed a human

diver when it exploded 15 to 30 cm from his head (Hirsch and Ommaya 1972). It broke

both eardrums, caused herniation of brain tissue and fracture of cranial bones. Based
134

partly on tests with dolphin cadavers, Myrick et al. (1990a) concluded that a 4-g seal

bomb will cause injury when detonated within 1.6 m of a dolphin and slight injury within

3.2 m. They estimated a safe standoff distance of 8 m. However, Cassano et al. (1990)

were unable to find a relationship between the use of seal bombs in the tuna fishery and

increased mortality of dolphins.

Anderson and Løken (1968) experimented on submerged rats with 1 g tetryl

charges. Lethality was increased by 200% when blasts were timed at 8 to 25 μsec apart.

They obtained 30% mortality with simultaneous detonation and 55% mortality with

single detonations. Charges set off within small intervals would be more dangerous

because animals would be subjected to a train of impulses.

A few other reports are not directly relevant because of differences in pressure vs.

time patterns (Wright and Allton 1971; Fuller and Kirkwood 1977).

Models of Effects of Explosives on Marine Mammals

Several workers have described procedures for calculating safe distances from

explosions to marine mammals (Yelverton et al. 1973; Hill 1978; Yelverton 1981; Goertner

1982; Wright 1982; O'Keeffe and Young 1984; O'Keeffe 1985; Young 1991; Craig and

Hearn 1998; Craig 2001). Their calculations are based on the following:

 degree of damage to various submerged land mammals at different impulse

levels, as determined primarily by Yelverton et al. (1973);

 the physical dependencies of impulse on charge weight, charge depth, range,

and mammal depth; and, in some cases,

 the relationship between animal weight and susceptibility to injury and death

(Yelverton 1981).

Hill suggests that the original Yelverton/Hill procedure probably overestimates the

zones of physical influence of shock waves on marine mammals: the respiratory

adaptations of marine mammals for diving probably reduce their susceptibility to sharp

pressure changes. Their auditory systems seem better protected in some ways than are

those of terrestrial mammals. The thick body walls of most marine mammal groups

probably also would reduce damage. Some of these assumptions may be incorrect.

The original Yelverton/Hill procedure does not allow for any relationship between

susceptibility and body size. Yelverton (1981) produced new equations for computing safe

distances for marine mammals that considered the animal's body mass. His equations

suggest that no damage would occur to a 100-kg marine mammal exposed to impulses of

289 Pa-s or less, and to a 1,000-kg marine mammal exposed to impulses of 702 Pa-s or

less. Yelverton (1981) determined that the impulse levels in Pa-s that could kill or damage

mammals are as follows:
135

50% Mortality ln(I) = 4.938 + 0.386 ln(M)

1% Mortality ln(I) = 4.507 + 0.386 ln(M)

No Injuries ln(I) = 3.888 + 0.386 ln(M)

where I = impulse in Pascal-seconds and m = body mass in kilograms. The relationships

between body mass and the magnitude of impulse causing injury or death to animals at the

water surface are shown in Table 6.5. Again, these equations are based on data from

submerged terrestrial mammals, and they may overstate the severity of injuries to marine

mammals adapted for life in the water. The direct applicability of the equations to large

marine mammals is particularly questionable, given that the largest animals from which

data are available are sheep.

Table 6.5

Impulses in Pascal-Seconds Needed to Cause Injury to Various Species of Marine

Mammals at the Water Surface, According to Yelverton’s (1981) Equations

Weight Injury (Impulse Pa-s)

Species lbs kg No Injury 1% Mortality 50% Mortality

0.2-kg marine mammal 0.2 26 49 75

Dolphin calf 27 12.2 128 238 366

Common dolphin 143 65 245 454 699

Spinner dolphin 143 65 245 454 699

Bottlenose dolphin 440 200 377 701 1,078

Risso's dolphin 660 300 441 819 1,261

Large whale 2,200 1,000 702 1,304 2,007

West Indian manatee 1,100 500 537 998 1,536

Yelverton (1981) calculated peak overpressure and impulses to the time of arrival

of the first surface cutoff wave using empirically determined equations:

1.10

3

1

45600





















 R

W Pm

3

1

0.168

3

1

0.0917 W

R

W























 

 c R DwDg R Co t 4 / 2  
136

















  	

	













      

10 10

11

1 1

11

9 c c t t

m I P e e

Where Pm = peak overpressure (kPa), Θ = time constant (msec), tc = time of arrival of the

surface cut off wave, I = impulse to cut off time (Pa-s), R = slant range (m), Dw depth of

charge (m), Dg = depth of guage (animal, m), Co =speed of sound in water (1.45 m/s), and

W = charge mass (kg).

The distances to the impulses causing injuries specified in Table 6.5 are shown in

Table 6.6. The distances were computed using Yelverton’s (1981) equations and assume a

22.7 kg charge at 50 m and the animal at the surface. This model is simplistic and should

not be used. It is used here for illustration.

Table 6.6

Distances in Meters to Impulses Causing No Injury, 1% Mortality, and 50% Mortality.

Impulses from Table 6.2. Distance Computed as per Yelverton's (1981)

Equations, Assuming a 22.7 kg Charge Detonated at 50 m Depth with the

Marine Mammal at the Surface

Distance (m) to Species No Injury 1% Mortality 50% Mortality

0.2 kg marine mammal 450 295 209

Dolphin calf 221 135 91

Bottlenose dolphin 128 72 46

Young (1991) presents a different set of equations, in his case to compute the safe

distance for marine mammals given a depth of blast of 61 m (200 ft):

Porpoise calf R = 578 WE

0.28

Porpoise adult R = 434 WE

0.28

20 ft Whale R = 327 WE

0.28

In these equations, R = the distance in feet from blast to the mammal, and WE is the

weight of the explosive in pounds. For a dolphin calf (12.2 kg) at the surface, the safe

range from a 22.7 kg charge would be 422 m. The Yelverton (1981) equation predicts no

harm to a 12.2 kg dolphin calf at an impulse of 128 Pa-s. For a dolphin calf at the surface,

this impulse would occur at a distance of 219 m if it was at the surface and at 778 m if the

calf was at a depth of 50 m (using the equations for estimating impulse provided by

Yelverton 1981).
137

When the explosion is near a hard (e.g., rock) bottom, shock waves may attenuate

less rapidly than in open water. Hill (1978) and Wright (1982) suggest that calculated

lethal ranges or safe distances should be doubled in these circumstances to ensure a

conservative safety margin.

Goertner (1982) produced a model to fit the data collected by Yelverton et al.

(1973) and Richmond et al. (1973). His model considered lung volume as a function of

animal weight and depth, and shock wave duration and impulse tolerance as a function of

animal weight and depth. In his model, because lung volume was a reduced at depth, it

was a smaller proportion of body mass so was more resistant to shock waves. His

parameter for scaling lung injuries as a function of depth was:

6

1

3

1

1

3

1

/ M o I  

where I is the impulse causing a specified damage in psi.msec, ρl is atmospheric pressure,

and ρo is pressure at depth in pounds per square inch, and M is the animal mass in

kilograms. The Yelverton et al. (1973) and Richmond et al. (1973) data indicate that

slight lung injury would occur at 20 psi-msec (138 Pa-s) for a 40-kg animal.

Atmospheric pressure was 12 psi, and hydrostatic pressure at 2 ft was 12.9 psi. These

data also showed that slight injuries to the intestinal tract occurred at a peak overpressure

(Pmax) of 600 psi (4,136 kPa) and at ambient pressure (ρo) of 12.9 psi. The damage

parameter for slight intestinal tract injuries was scaled as

Pmax/ ρo

Craig and Hearn (1998) and Craig (2001) used Goertner's method to determine distances

to various injury levels using the lowest body mass and lowest impulses for which onset

of slight lung damage, extensive lung hemorrhage, and extensive lung injury occur.

Onset of slight lung injury:

I = 19.7 (M/42)1/3 psi-milliseconds

I =136 (M/42)1/3 Pascal-seconds

Onset of extensive lung hemorrhage (1% mortality):

I1% = 42.9 (M/34)1/3 psi-milliseconds

I1% =296 (M/34)1/3 Pascal-seconds

Occurrence of extensive lung injury (50% mortality):

I50% = 84.9 (M/42)1/3 psi-milliseconds

I50% =586 (M/42)1/3 Pascal-seconds

Craig and Hearn (1998) and Craig (2001) compared results of these equations to

Yelverton’s equations for no injury, 1% mortality, and 50% mortality and found that they

were slightly more conservative than the Yelverton equations. In addition, the predicted

impulses were no greater than measured impulses causing the same type of injury in

laboratory tests. The above equations were used to predict the zones of no injury,

1% mortality, and 50% mortality for marine mammals in the ship shock Environmental

Impact Statements (EISs) (Department of the Navy 1998, 2001).
138

The impulses causing injury in Table 6.7 were computed for animals at the water

surface. The Seawolf and DDG81 EISs (Department of the Navy 1998, 2001) used the

impulse value associated with onset of extensive lung hemorrhage (1% mortality) for a

27-pound (12.2 kg) dolphin calf as the criteria for mortality and the impulse associated

with slight recoverable lung injury as a criterion for injury. These impulse values were

calculated with Craig and Hearn’s (1998) and Craig's (2001) adaptation of the Goertner

(1982) model. The impulse predicted to cause slight injury in a 12.2 kg dolphin calf was

90 Pa-s at the surface, and the impulse to cause 1% mortality was 210 Pa-s at the surface.

Table 6.7

Impulses Causing Various Degrees of Injury Computed According to the Method of

Craig (2001)

Weight Pa-s

Species lbs kg Slight Injury 1% Mortality 50% Mortality

0.2-kg marine mammal 0.5 0.2 23 53 99

Dolphin calf 27 12.2 90 210 388

Common dolphin 143 65 157 367 678

Spinner dolphin 143 65 157 367 678

Bottlenose dolphin 440 200 229 534 986

Risso's dolphin 660 300 262 612 1,129

Large whale 2,200 1,000 391 914 1,686

West Indian Manatee 1,100 500 311 725 1,338

The safe range for marine mammals is slight injury to a 0.2-kg marine mammal.

Goertner (1982) assumed that damage was related to lung volume as a function of

body mass. Lung volume at the surface was assumed to be 3% of body mass and

decreased with increasing depth. Goertner (1982) and Craig (2001) thought that as depth

increases, the lung and tissues compress and a larger impulse was required to cause

damage (Table 6.8).

Recently the effect of depth on acoustical resonance of gas filled structures has

been raised as a potential issue with respect to affects of loud noise on marine mammals.

This may cause or impair gas exchange. Gisner (1998) states “if the lung resonance

changes as a function of depth then as depth changes, the frequency function for damage

risk threshold will need to be adjusted.” The duration of blast impulses are too short to

have this kind of effect (NOAA 2002). However, decompression type effects in marine

mammals may be an issue (NOAA 2002). There is the potential for long duration high

intensity sound to generate bubbles (NOAA 2002). Blast pulses are of short duration, but

the rapid fluctuation between positive and negative pressures could induce bubble

formation. Reidenberg and Laitman (2003) found bubbles within the tissues adjacent to

air spaces of dead odontocetes exposed to underwater blasts.
139

Table 6.8

Impulses Required to Cause Various Levels of Injury to a Dolphin Calf and Slight Injury

to a 0.2-kg Marine Mammal, as a Function of Depth (From: Craig, Pers. Comm.)

12.2 kg Dolphin Calf 0.2 kg Marine Mammal Depth Mortality (Pa-s)

feet meters

Slight Injury

(Pa-s) 1% 50%

Slight Injury

(Pa-s)

0 0 90 194 389 23

3.3 1 95 206 408 24

33 10 127 278 550 33

164 50 220 481 951 56

328 100 299 650 1,285 75

656 200 413 899 1,779 105

Ongoing work by Ketten et al. (2003) and Reidenberg and Laitman (2003) shows

that extensive damage can occur at the boundaries between tissues of different densities.

Preliminary results of this work and the concern about bubble formation indicate that

depth may not confer increased resistance to trauma or that the resistance may not be as

large as once thought. It is also hoped that results of this ongoing work will validate,

refine, or redefine current marine mammal injury models.

In the ship shock EISs, tympanic membrane rupture was also considered as a

criterion for slight injury. Peak blast overpressures of 1,034 kPa (150 psi) are associated

with 50% tympanic membrane rupture (Ketten 1998). Craig (2001) and Sigurdson et al.

(2001) determined that acoustic energy proportional to P2/t (P = pressure and t = time)

may be an appropriate parameter for response of the ear to high levels of underwater

noise. Based on the incidence of eardrum rupture in sheep exposed to underwater

explosions by Richmond et al. (1973), Craig (2001) estimated that 50% tympanic

membrane rupture would occur at an energy flux density of 1.17in-lb/in2

. This criteria is

more conservative than one derived by Ketten (1995) and was used in the ship shock

EISs as another criterion for injury.

The criteria for marine mammal injury were as follows:

 Mortality occurs at the range of onset of extensive lung hemorrhage

(1% mortality) in a 12.2-kg dolphin calf;

 Injury occurs at the range of onset slight lung injury for a 27-pound (12.2-kg)

dolphin calf, or the incidence of 50% tympanic membrane rupture

(1.17 in-lb/in2

); and

 A safe range is one beyond which there could be slight lung injury to a 0.2-kg

marine mammal.
140

Criteria and Definitions of Blast Injury Used and Accepted by NOAA-F

Impact assessment of the effects of underwater explosives on marine mammals

must addresses the potential for “takes” of marine mammals as defined in the MMPA, as

amended in 1994 (16 C.F.R. § 1431 et seq.).

As defined in the MMPA, the term “take” means “to harass, hunt, capture, or kill,

or attempt to harass, hunt, capture, or kill any marine mammal.” Under the 1994 MMPA

amendments, Congress defined and divided the term “harassment” to mean “any act of

pursuit, torment, or annoyance which: 1) (Level A Harassment) has the potential to injure

a marine mammal or marine mammal stock in the wild; or 2) (Level B Harassment) 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.”

Underwater explosions can kill or injure marine mammals through direct physical

effects. Also, marine mammals exposed to loud sounds can experience temporary

reduction in hearing sensitivity (TTS), which NOAA-F considers to be potentially

significant and to constitute “take.” Changes in behavior can also be considered to be

“takes” under the MMPA.

NOAA-F does not consider minor and temporary behavioral responses with no

likely consequences for the well-being of individual marine mammals, e.g., minor startle

or alert reactions, to be biologically significant or to be considered as “takes” (Federal

Register 61(234):64,337). In the case of single underwater explosions, minor or

momentary behavioral responses are not considered to be “takes” (Federal Register

66(87):22,452).

For repetitive impulses (seismic pulses), NMFS (1995b) accepted TTS as the

definition of the lower bound for Level A harassment for seismic sounds. Off the coast

of California, the limits for TTS were set at 180 dB re 1 μParms for mysticetes and sperm

whales and at 190 dB re 1 μParms for odontocete cetaceans and pinnipeds (NMFS 1995a).

That is, these were the levels below which it was assumed there would be no harassment

and above which this could not be stated with certainty. However, as of March 2000,

NMFS indicated that “odontocetes also be limited to an SPL no greater than

180 dB re 1 Pa RMS” (NMFS 2000). NMFS indicated that the 190 dB value would still

apply for pinnipeds. In a later determination, NMFS has defined TTS as the upper

portion of the Level B harassment zone and near the lower portion of the Level A

harassment zone for single underwater acoustic events such as shock testing of ships and

submarines (NMFS 1999, 2001).

In 1995, NMFS ruled on the use of explosives to remove offshore oil and gas

structures in the Gulf of Mexico (Federal Register 60(197):53,139-53,147). The radius

of effect for injury was determined to be 914 m. Monitoring was required to ensure that

the area was clear of marine mammals prior to detonation. There has been some

advancement in knowledge of effects on marine mammals since 1995, particularly in the
141

area of temporary threshold shift and refinements to models of underwater injury. Recent

EISs and ruling by NMFS have incorporated this knowledge

Level B Harassment for Explosives

The Seawolf and Winston Churchill EISs (Department of the Navy 1998, 2001)

defined Level B harassment as the onset of TTS. NMFS accepted the onset of TTS as the

definition of harassment for an explosive source during the Seawolf (Federal Register

64(3):3,280-3,286) and Winston Churchill ship shock tests (Federal Register

66(87):22,450-22,467).

In the Seawolf and Winston Churchill ship shock EISs (Department of the Navy

1998, 2001), harassment was defined as the TTS criterion, which is the safe outer limit

for recoverable auditory damage. TTS was assumed to be induced:

1) at energies greater than 182 dB re 1 microPascal2

-second within any

1/3 octave band. Their procedure for calculating critical distances for TTS

was:

 calculate the energy density spectrum for the waveform;

 integrate the spectrum in 1/3 octave bands;

 determine if the energy density in any 1/3 octave band exceeds

182 dB re 1 microPascal2-sec (considering frequency ranges of 100 Hz

for toothed whales and 10 Hz for baleen whales); and

2) if the peak pressure exceeded 12 psi for an explosive source.

The distance to each criterion was determined and the shortest distance at which either

criterion is exceeded was taken to be the distance at which Level B harassment (TTS)

would begin to occur.

Level A Harassment for Explosives

Department of the Navy (1998, 2001) defined Level A harassment as follows:

1) Mortality occurs at the range of onset of extensive lung hemorrhage

(1% mortality) in a 12.2-kg dolphin calf; and

2) Injury occurs at the range of onset slight lung injury for a 27-pound

(12.2-kg) dolphin calf, or the incidence of 50% tympanic membrane rupture.

These definitions were accepted by NMFS (2001; Federal Register

66(87):22,450-22,467).

Criteria for Multiple Shots

If more than one shot is to be used, then the timing between shots is a critical

factor to be considered in derivation of safe distances. As shown in Chapter 4, timing
142

between shots and numbers of shots used are specified so that an array effect is avoided.

There are no guidelines for multiple shots. The following are suggested criteria for

multiple shots used to decommission platforms in the Gulf of Mexico.

The specified 900 ms interval between shots is probably not enough time for an

animal to recover from TTS or other damage. Given that recovery from TTS requires

minutes to days, it may be prudent to add energy from all shots fired in 1 day to

determine the TTS threshold distance.

The following approach could be used to determine distances causing injury or

death for multiple shots carried out within a 24-hour period:

1) Determine the distance to onset of slight injury for a 0.2-kg marine mammal

for the largest shot. Beyond this distance, there should be no damage to

marine mammals from multiple shots.

2) Sum the energy of all the shots and determine the distance to onset of slight

lung injury for a 12.2-kg dolphin calf. If this distance is less than that

computed in 1), then use that as the distance to onset of slight lung injury; if

not, use the distance computed in 1).

Summary

Charges used for well severance are detonated 4.6 m (15 ft) below the mudline.

There is evidence showing that, for these kinds of charges, the blast parameters are

variable – they may be reduced considerably, to a minor extent, or not reduced at all.

For charges jetted into rock, peak pressure can be reduced to 5% of that in open

water and impulse by 30% (Nedwell et al. 2002). The duration of the blast wave is

increased to 1 to 2 ms, and more importantly the rise time is greatly increased to the order

of 1 ms. Unconfined charges have very short rise times of about 20 μs and pulse

durations of about 0.2 to 0.5 ms. Rock has a much higher density and compressional

wave velocity than does water. As the density and compressional velocity approach

those of water, the blast wave characteristics of the substrate approach those of water, and

coupling between substrate and water improves.

Charges used for well severance in the Gulf of Mexico are generally 22.7 kg, and

these are set off 4.6 m below the sediment/water interface. Powell (1995) analyzed

Connor's (1990) data from one rig in the Gulf of Mexico and found that the peak pressure

of explosives jetted into the substrate depended more on charge weight than on burial

depth. He found that that the attenuation coefficient for sediment was larger than that of

water at that site. Peak pressure was reduced by 50% to 75% (Connor 1990). As the

attenuation of the sediment tends to approach that of water, the reduction of peak

pressure and impulse due to burial also decreases (see Chapter 4). Thus, at one rig in the

North Sea, Nedwell et al. (2002) found no reduction in peak pressure for 45-kg charges

used to sever wellheads at 3 m below the water/substrate interface. They claim that these
143

results imply that the sediment did not act as effective confinement for the blast in that it

was of comparable density to that of water.

Wright and Hopkey's (1998) equations for a safe setback or burial distances to

protect fish habitat predict lower reductions of peak pressure than those found in the Gulf

of Mexico by Connor (1990), but higher than the 0% reduction found in the North Sea.

Their guidelines use a distance/depth sufficient to insure that the explosive bubble is

contained by the sediment. The 45-kg charges buried 3 m into the substrate of the Gulf

of Mexico produced a peak pressure of 100 kPa (15 psi) at a distance of about 450 m

from the source (Connor 1990). According to Wright and Hopky (1998), a 5-kg charge

would need to be buried at least 5 m below the unconsolidated mud/water interface to

produce a peak pressure of 100 kPa at the mud/water interface 0 m from the blast site.

The evidence presented above shows that measurement of blast parameters after

the fact or modeling using sediment characteristics at the specific site is the only way of

determining them (see Chapter 4). Modeling seems of little use without site specific

sediment data. Thus, for the purposes of impact assessment, the prudent assumption

should be that charges used for well severance behave in the same manner and produce

parameters of the same magnitude as do charges detonated on the bottom in open water.

6.4 Data Gaps and Recommended Areas of Future Research

6.4.1 Marine Fishes

The fact that underwater explosions at close range kill adult fishes with

swimbladders is well established. Nevertheless, even from the limited number of

platform removals that have been monitored, there was considerable variability in

numbers of individuals killed relative to the estimated extant populations (G. Gitschlag,

NMFS, pers. comm.). Properly designed caging experiments used during actual platform

removals may shed light on the nature of this variability.

There is an appreciable gap in the knowledge about sublethal and behavioral

effects of short-term exposure to high impulse sound on adult and early life stage fishes.

For example, limited evidence suggests that high impulse sounds can permanently

damage sensory hair cells in the middle ear of fishes (McCaulay et al. 2003). Detailed

anatomical evaluations of this type of injury should be analyzed using histological

techniques that would reveal possible sublethal effects. Govoni et al. (2002)

demonstrated that caging studies would work on larval and early juvenile fishes. There is

no information on the use (or not) of auditory cues by larvae or early juveniles of Gulf of

Mexico fishes. This could be documented with field experiments using hydrophone

playbacks.

6.4.2 Marine Turtles

Very little information exists regarding the effects of underwater explosions on

marine turtles. The effects of explosions to humans and other terrestrial mammals, or
144

marine mammals is not reliably extrapolated to marine turtles. It may be possible to

collect supportive data concerning explosion parameters that may result in non-lethal

injuries to the marine turtle auditory mechanism or other gas-filled organs by conducting

tests on non-listed aquatic turtle species. Studies designed to ascertain damaging effects

(nonlethal or lethal) of underwater explosions on marine turtle organs and other tissues

may utilize dead marine turtles, similar to ongoing and successful studies conducted on

dead marine mammals by Ketten et al. (2003).

Visual census methods (i.e., shipboard and aerial surveys) appear to provide the

most reliable means to date to determine the presence of marine turtles around offshore

oil and gas structures prior to explosive removals. Active underwater acoustic methods

are untested, and data may be confounded by subsurface structures as well as the

presence of large fishes or aggregations of fishes associated with offshore structures.

6.4.3 Marine Mammals

There are five principal kinds of knowledge required to address and mitigate

impacts on marine mammals:

 Explosion parameters that cause recoverable hearing loss (TTS);

 Explosion parameters that cause onset of recoverable injury or slight trauma;

 Explosion parameters that cause permanent injury or death;

 Effects of multiple shots; and

 Detection of marine mammals with in the safety zones.

In terms of explosion parameters that cause injury, received sound levels that

cause TTS are the best known. However, none of these data are based on sounds with

rise times comparable to those of high explosives. We do not know if the rise time is a

factor in inducing TTS. Damage risk criteria are not available for humans or terrestrial

animals (Ahroon et al. 1996), so it is not possible to extrapolate from terrestrial to marine

mammals.

Blast parameters causing PTS and tympanic membrane rupture are unknown, and

only educated guesses are available. Blast parameters causing recoverable and

permanent injury or death have been extrapolated from submerged terrestrial animals. It

not known how well these data translate to effects on marine mammals, however, Ketten

et al. (2003) are currently conducting this kind of research with dead marine mammals

with apparent good results.

The effect of depth on blast resistance and decompression type effects require

some attention. The current models assume that depth confers some protection from blast

injury, but this may not be the case.

The time interval between shots may be an important mitigation measure. The

amount of time for an animal to recover from a shock wave is unknown. Do closely

spaced shock waves, each of which is insufficient to cause damage, cause damage in
145

proportion to 1) the sum of all damage parameters, or 2) a sum of a time dependent

percentage of damage parameters? The ship shock tests were single blasts with one or

more days between shots. The effects of short time intervals between blasts such as those

used in the Gulf of Mexico have not been addressed.

Detection of marine mammals in the Gulf of Mexico is complicated by the

presence of animals that make long deep dives. Thus, acoustic as well as visual

observations are needed to ensure that animals are not in the area. However, this method

will not work for species that do not call while underwater. Not enough is known about

the vocal behavior of beaked whales and some other species to determine the probability

of their being detected by passive acoustical methods.

The Office of Naval Research (ONR) is conducting research on TTS, effects of

blast parameters on marine mammals, and detection of marine mammals with passive

acoustic devices. Synergy between MMS and ONR in these areas of research would be

fruitful. The Department of the Navy, Naval Surface Warfare Center is measuring actual

blast parameters in the sea and working on new and/or revisions to blast propagation

models. Synergy with this group also would be fruitful.
147

CHAPTER 7

MITIGATION AND MONITORING

7.1 Marine Fishes

Measures used by various state agencies to mitigate planned explosions in aquatic

(freshwater) settings were reviewed by Keevin (1998). The following were fundamental

categories for developing mitigative strategies:

 blasting design;

 biological criteria; and

 physical mitigation features.

Keevin (1998) concluded that blasting contractors must work more closely with natural

resource agencies to reduce potential adverse effects and recommended that blasting

permits be required. MMS’s existing platform removal permit includes aspects from

each of these categories (see Chapter 2). Blasting design parameters that can affect the

extent of fish kill associated with an underwater explosion are discussed in detail in

Chapters 3 and 4. These include charge weight, charge type, shaped charges, and

decking. Biological criteria described by Keevin (1998) were lethal range models,

observers, compensation of fishery losses, pre-blast sampling surveys to detect fish

presence, and seasonal restrictions on blasting that coincide with spawning, migratory, or

other aggregation times. Physical mitigation strategies used in the past either seek to

drive fishes away from the blast site with small charges or low frequency noise, or to

lessen the severity of the shock wave with bubble curtains or physical barriers. These

recommendations work well for blasting projects in inland and possibly coastal waters,

but most are not applicable or economically feasible for offshore oil and gas platforms.

For example, bubble curtains would certainly help reduce fish kills associated with

platform removal, however, such devices would have to be fabricated for each different

removal scenario. Design and development cost would be very high.

For platform removal, blasting design is affected by permit requirements.

According to MMS, operators may propose any type of blasting design. If the design

does not conform to one of those encompassed under the generic incidental take

statement, a special consultation must occur to review the requested action. Biological

criteria such as pre-blast surveys for marine mammals and turtles are required in the

MMS permit. NMFS observers also may be present during removal operations to

estimate the number of dead fishes floating on the surface following a detonation. When

possible, NMFS personnel collect fish samples, which are identified to species, counted,

and measured. However, these efforts conducted by NMFS personnel are not required

under the MMS permit. As part of this requirement, numbers and kinds of fishes floating

at the surface are qualitatively estimated following the detonation.

Other than the items already covered in the current MMS permit regarding blast

design, benefits of mitigation and monitoring for fishes in the Gulf of Mexico and Santa
148

Barbara Channel would not outweigh the costs. In Cook Inlet, AK, where economically

important species such as Pacific herring and salmon could occur in the vicinity of

platforms, mitigation procedures should include temporal windows to avoid peak

spawning/aggregation times, observers and pre-blast remote sensing to detect large

aggregations of fishes, and if critical times cannot be avoided, physical barriers should be

deployed.

7.2 Marine Turtles

The discovery of beached marine turtles and bottlenose dolphins following the

1986 explosive platform removal event (Section 6.2) prompted the initiation of formal

consultation authorized through Section 7 provisions of the ESA of 1973 (16 U.S.C.

1531-1543) between two federal agencies with jurisdiction in federal waters: NMFS and

MMS (Henwood 1988). The purpose of this consultation was to determine a mechanism

to minimize potential impacts to listed species. Further, in consideration of MMPA, the

agencies discussed the potential for unintentional (i.e., incidental) take and proposed take

limits for future explosive removal activities (Richardson 1989). The consultation

resulted in a requirement for oil and gas companies to obtain a permit (through separate

consultations on a case-by-case basis) from the MMS prior to using explosives in federal

waters. Because many offshore structure removal operations are similar, a “generic”

Incidental Take Statement was established by the NMFS on 25 July 1988 that describes

requirements to protect marine turtles. A summary of these requirements, as described in

Richardson (1989) and Gitschlag et al. (1997), are listed in Table 7.1. To be considered

under the “generic consultation,” a proposal for an explosive structure removal had to

meet the following limitations, as established by the NMFS (from Richardson 1989):

1) High velocity explosives with a detonation rate of 7,600 m/s or greater must

be used;

2) Each explosive charge cannot exceed 50 lb (with a maximum 50 lb backup

charge);

3) Charges must be placed a minimum of 5 m (15 ft) below the seafloor (mud

line); and

4) Detonations must be limited to groups of eight or less, with a minimum of

900 ms (0.9 second) between each detonation.

Similar procedures were adopted for explosive structure removals within state

waters, where permits were managed and obtained by the U.S. Army Corps of Engineers.

In 1987, the NMFS initiated a marine turtle observer program that followed the

guidelines specified in the NMFS Incidental Take Statement (Table 7.1) at all oil and gas

structure explosive removal sites in both state and federal waters of the Gulf of Mexico

(Gitschlag 1990). Aerial survey techniques were found to be approximately 10 times

more effective in observing marine turtles than day or night surface surveys (i.e., from

vessels and from oil and gas platforms). From these studies, turtles were primarily

sighted near structures positioned in water depths of 15 to 60 m (Gitschlag et al. 1997).

From 1987 through 1988, surveys sighted turtles at 13% of the structures removed
149

(Gitschlag and Renaud 1989). Surveys conducted during 1992 and 1993 sighted marine

turtles at 20% and 13% of the structures monitored, respectively (Gitschlag and Herczeg

1994; Gitschlag et al. 1997). The marine turtle observer program has been successful in

mitigating impacts to marine mammals and turtles associated with the explosive removal

of offshore structures. However, even with these protective measures in place, there have

been observations of marine turtles impacted by explosive platform removals (Table 7.2)

(G.R. Gitschlag 2003, pers. comm., NOAA-F, Galveston, TX).

Table 7.1

Summary of the National Marine Fisheries Service “Generic” Incidental Take Statement

Regarding the Protection of Marine Turtles Prior to and During the Explosive Removal

of Offshore Structures (From: Richardson 1989 and Gitschlag et al. 1997)

1) Qualified observers must monitor the area around the site for marine turtles

beginning 48 hours prior to detonations;

2) A 30-minute aerial survey must be conducted within 1 hour prior to and after

detonation;

3) If marine turtles are observed within 1,000 yards of the structure prior to

detonation, detonations must be delayed until the animals have moved beyond

1,000 yards. The aerial survey must also be repeated;

4) Detonations must occur no sooner than 1 hour after sunrise and no later than

1 hour before sunset;

5) During salvage-related diving, divers must report turtle and mammal sightings. If

turtles are thought to be resident, pre- and post-detonation diver surveys must be

conducted;

6) Explosive charges must be staggered to minimize cumulative effects of the

explosions;

7) Avoid the use of "scare" charges to frighten away turtles that may be attracted to

the point of detonation to feed on dead marine life and be subsequently exposed to

explosions; and

8) The structure removal company must file a report summarizing the results.

Table 7.2

Marine Turtles Impacted from Explosive Structure Removals from 1987 to May 2003

(From: G.R. Gitschlag 2003, Pers. Comm.)

Month Year Species Observed Condition

October 1990 Caretta caretta Cracked shell

November 1997 Caretta caretta Cracked shell

July 1998 Caretta caretta Dead from blast

August 2001 Caretta caretta Stunned from blast

Note: Caretta caretta = loggerhead turtle.
150 

Subsequent to the marine turtle mortalities associated with underwater 

detonations in 1981 (Section 6.2.2), O’Keeffe and Young (1984) proposed that a safe 

range for marine turtles from a free-field underwater explosion could be expressed by the 

equation R = 200 w 1/3, where R is the safe distance, or range, in feet and w is the charge 

weight in pounds. This equation was later modified by Young (1991) to R = 560 w 1/3, 

based on estimates of safe ranges as established by the NMFS for explosive platform 

removals. The metric form of this equation is R (m) = 222 W(in kg)1/3. Young (1991), 

however, suggested that calculated marine turtle safe ranges should only be used for 

preliminary planning purposes. For example, applying the Young (1991) equation for 

safe distances to observations recorded in Klima et al. (1988), this equation predicts a 

safe range of 1,003 m (3,291 ft), which is slightly greater than the greatest distance at 

which an effect was observed (i.e., a turtle was rendered unconscious at a distance of 

915 m [3,000 ft], the greatest distance tested) (Department of the Navy 2001). These 

results suggest that explosive impacts might be realized at distances greater than 915 m 

(3,000 ft); additional research is necessary to further refine models that estimate safe 

distances for marine turtles exposed to explosive removal operations. 

Using the O'Keeffe and Young (1984) data for marine turtles, a model developed 

by Goertner (1982) for calculating the ranges for occurrence of two types of internal 

organ injury to marine mammals exposed to shock waves associated with an underwater 

explosion was run for the test conditions for the onset of lung hemorrhage, onset of 

extensive lung hemorrhage, and extensive lung hemorrhage (Department of the Navy 

2001). Prediction results from this test were consistent with the mortal injury suffered by 

the 181-kg (400-lb) turtle located 152 to 213 m (500 to 700 ft) from the detonation, the 

minor injuries suffered by the 91- to 136-kg (200- to 300-lb) turtle 366 m (1,200 ft) from 

the detonation, and the uninjured 91- to 136-kg (200- to 300-lb) turtle 610 m (2,000 ft) 

from the detonation. These results suggest that lung injury predictions for marine turtles 

are not inconsistent with predictions for small mammals, as developed for the impact 

analysis of the Final EIS for the DDG 81 shock trial (Department of the Navy 2001). 

Keevin and Hempen (1997) suggest that it may be possible to protect marine 

turtles from underwater explosions by either avoiding periods when they are in the 

project area or by removing the turtles from the project area. Depending on location and 

species, there may be time periods when certain marine turtle species are not in the 

project area due to life history or migration patterns, or seasonally. These periods may be 

determined by coordination with the state natural resource agency or NOAA-F. 

Theoretically, detonations may be planned during time periods of low turtle abundance. 

However, in areas such as the Gulf of Mexico, marine turtles are ubiquitous during all 

seasons except perhaps during mid-winter months when seawater temperatures are 

depressed. Explosive removal activities during these months rarely occur because of 

inclement weather conditions. As a last resort, turtles have been physically captured and 

removed from the project area. This method is considered inefficient and unreliable. 
151

In 1995 and 2002, NMFS implemented monitoring and mitigation measures to

reduce or eliminate the potential for impact to marine turtles and marine mammals, as

detailed in the following section.

7.3 Marine Mammals

In recent years, monitoring and mitigation have been required to protect marine

mammals when explosives are used in the marine environment. An LOA was issued in

1995 by NMFS for the incidental take of marine mammals during removal of oil and gas

structures in the Gulf of Mexico (Federal Register 60(197):53,139-53,147). The

following monitoring and mitigation measures were required:

(a) Observer(s) approved by the NMFS in advance of the detonation

must be used to monitor the area around the site prior to, during, and

after detonation of charges.

(b) (1) Both before and after each detonation episode, an aerial survey

by NOAA-F-approved observers must be conducted for a period

not less than 30 minutes within 1 hour of the detonation episode.

To ensure that no marine mammals are within the designated

3,000 ft (1,000 yd, 941 m) safety zone nor are likely to enter the

designated safety zone prior to or at the time of detonation, the

pre-detonation survey must encompass all waters within 1 nmi of

the structure.

(2) A second post-detonation aerial or vessel survey of the

detonation site must be conducted no earlier than 48 hours and no

later than 1 week after the oil and gas structure is removed, unless

a systematic underwater survey, either by divers or

remotely-operated vehicles, dedicated to marine mammals and

sea turtles, of the site has been successfully conducted within

24 hours of the detonation event. The aerial or vessel survey

must be systematic and concentrate down-current from the

structure.

(3) The NOAA-F observer may waive post-detonation monitoring

described in paragraph (b)(2) of this section provided no marine

mammals were sighted by the observer during either the required

48 hour pre-detonation monitoring period or during the

pre-detonation aerial survey.

(c) During all diving operations (working dives as required in the course

of the removals), divers must be instructed to scan the subsurface

areas surrounding the platform (detonation) sites for bottlenose or

spotted dolphins and if marine mammals are sighted to inform either
152

the U.S. government observer or the agent of the holder of the LOA

immediately upon surfacing.

(d) (1) A report summarizing the results of structure removal activities,

mitigation measures, monitoring efforts, and other information as

required by an LOA, must be submitted to the Director,

NOAA-F, Southeast Region, 9721 Executive Center Drive N,

St. Petersburg, FL 33702 within 30 calendar days of completion

of the removal of the rig.

(2) NOAA-F will accept the U.S. Government observer report as the

activity report if all requirements for reporting contained in the

LOA are provided to that observer before the observer’s report is

complete.

These requirements were updated in August 2002 (Federal Register

67(148):49,869-49,875). While nearly identical to the mitigation, monitoring, and

reporting requirements previously issued in 1995, the 2002 requirements included

several new and important additions, including

1) In water depths of 150 ft (46 m) or greater, or in cases where divers are

not deployed in the course of normal removal operations, an ROV

must be deployed prior to detonation to scan areas below structures. If

marine mammals are sighted, the ROV operator must inform either the

NMFS-approved observer or the agent of the holder of the LOA

immediately; and

2) In water depths of 328 ft (100 m) or greater, passive acoustic detection

must be employed prior to detonation. If marine mammals are

detected by the acoustic device, the operator must inform either the

U.S. government observer or the agent of the holder of the LOA

immediately.

An LOA was issued in 1999 and 2001 for the U.S. Navy's ship shock tests.

Monitoring was required during the Seawolf ship shock test (Federal Register

64(3):3,280-3,286) and the Winston Churchill ship shock test (Federal Register

66(87):22,450-22,467). The following monitoring with respect to marine mammals was

required for the Winston Churchill test.

“(a) The holder of the Letter of Authorization is required to cooperate with

the National Marine Fisheries Service and any other Federal, state or

local agency monitoring the impacts of the activity on marine

mammals. The holder must notify the appropriate Regional Director

at least 2 weeks prior to activities involving the detonation of

explosives in order to satisfy paragraph (f) of this section.
153

(b) The holder of the Letter of Authorization must designate qualified

on-site individuals, as specified in the Letter of Authorization, to

record the effects of explosives detonation on marine mammals that

inhabit the Atlantic Ocean test area.

(c) The test area must be surveyed by marine mammal biologists and

other trained individuals, and the marine mammal populations

monitored, 48-72 hours prior to a scheduled detonation, on the day of

detonation, and for a period of time specified in the Letter of

Authorization after each detonation. Monitoring shall include, but not

necessarily be limited to, aerial and acoustic surveillance sufficient to

ensure that no marine mammals are within the designated safety zone

nor are likely to enter the designated safety zone prior to or at the time

of detonation.

(d) Under the direction of a certified marine mammal veterinarian,

examination and recovery of any dead or injured marine mammals

will be conducted. Necropsies will be performed and tissue samples

taken from any dead animals. After completion of the necropsy,

animals not retained for shoreside examination will be tagged and

returned to the sea. The occurrence of live marine mammals will also

be documented.

(e) Activities related to the monitoring described in paragraphs (c) and

(d) of this section, or in the Letter of Authorization issued under §

216.106, including the retention of marine mammals, may be

conducted without the need for a separate scientific research permit.

The use of retained marine mammals for scientific research other than

shoreside examination must be authorized pursuant to subpart D of

this part.

(f) In coordination and compliance with appropriate Navy regulations, at

its discretion, the National Marine Fisheries Service may place an

observer on any ship or aircraft involved in marine mammal

reconnaissance, or monitoring either prior to, during, or after

explosives detonation in order to monitor the impact on marine

mammals.

(g) A final report must be submitted to the Director, Office of Protected

Resources, no later than 120 days after completion of shock testing

the USS Winston S. Churchill. This report must contain the

following information:

(1) Date and time of all detonations conducted under the Letter of

Authorization.

(2) A description of all pre-detonation and post-detonation activities

related to mitigating and monitoring the effects of explosives

detonation on marine mammal populations.
154

(3) Results of the monitoring program, including numbers by

species/stock of any marine mammals noted injured or killed as a

result of the detonation and numbers that may have been

harassed due to presence within the designated safety zone.

(4) Results of coordination with coastal marine mammal/sea turtle

stranding networks.”

The Gulf of Mexico permit required aerial surveys prior to the explosions to

ensure that no marine mammals were within the safety radius. Post-explosion monitoring

was required to search for the presence of dead or injured animals. The monitoring

required for the Winston Churchill test added passive acoustic monitoring to the

requirements.

During explosive platform removal in the North Sea, visual monitoring from the

vessel, passive stereo hydrophones, and sonobuoys were used to detect marine mammals

(Nedwell et al. 2002). A seal acoustic harassment device was used to scare resident seals

away from the blasting site.
155

CHAPTER 8

DISCUSSION AND RECOMMENDATIONS

Previous chapters have reviewed the different technologies used for explosive

structure removals, the physics of underwater detonations, and potential impacts on

fishes, sea turtles, and marine mammals. This chapter discusses the findings, identifies

data gaps, and recommends topics where further study would be appropriate.

This report has focused on three faunal groups: fishes, sea turtles, and marine

mammals. Sea turtles and marine mammals are federally protected species for which

death or injury of individual animals is a serious concern. In contrast, although many fish

species associated with offshore platforms are federally managed, impacts on stocks or

populations are the main concern, rather than death or injury of individuals. While

mitigation and monitoring requirements have been established for marine mammals and

turtles, there are no measures specifically developed to protect fishes; rather, it is

assumed that fish kills are unavoidable during explosive structure removals.

Environmental data concerning platform removals serve two main purposes: 1) to

allow impacts to be estimated (e.g., numbers of animals that may be killed or injured

during structure removals); and 2) to aid in developing or refining mitigation measures

that prevent or reduce the likelihood of impacts. Sources of data have included

laboratory and field experiments, modeling studies, and anecdotal field observations.

There are important differences among the three faunal groups discussed in this report

with respect to the types and adequacy of data available (Table 8.1). In general, fishes

are the best-studied group, and sea turtles the least studied.

Table 8.1

Types and Amounts of Data Available Regarding Impacts of Underwater Detonations on

Fishes, Sea Turtles, and Marine Mammals

Types of Data Available Group Experimental Studies Modeling Anecdotal Observations

Fishes  Numerous lab and field studies of

explosive effects

 Quantitative studies following

actual structure removals

 Extensive  Many observations

(e.g., fish kills)

Sea turtles  One study with caged turtles

during platform removal (but no

pressure measurements)

 Very limited  Mortalities, injuries,

strandings following

detonations

Marine

mammals

 Recent studies of explosive effects

on dolphin carcasses

 A few auditory effects studies but

most not for explosives

 Several studies on behavioral

effects of seismic sources but

limited relevance

 Limited efforts,

mostly connected

with ship shock

trials; some

models used data

from terrestrial

mammals

 Mortalities, injuries,

strandings following

detonations
156

8.1 Fishes

As discussed in Section 6.1, lethal effects of underwater explosions on numerous

species of fishes have been studied in laboratory and field experiments and have been

modeled extensively. These data and models have been used to calculate effect ranges.

In addition, there have been studies specifically designed to estimate fish kills associated

with structure removals in the Gulf of Mexico (Gitschlag et al. 2000).

One set of calculations reviewed in Table 6.3 predicts effect ranges varying from

12 m for non-swimbladder species to 230 to 349 m for swimbladder species. Actual

observations following structure removal detonations indicate most dead fishes were

within 25 m, with numbers declining with distance out to 100 m (Gitschlag et al. 2000).

Other surveys have shown that fish densities around platforms are highest within a

horizontal distance of 18 to 50 m from the structure (Stanley and Wilson 1998, 2002).

Therefore, it seems that most fishes associated with platforms are close enough to be

killed or injured by a typical underwater detonation associated with structure removals.

Of course, there are many variables affecting the fate of individual fishes, including their

size, shape, vertical position in the water column, and orientation relative to the

detonation source.

The main goal with respect to fish populations is predicting impacts rather than

setting “safety ranges” for mitigation/monitoring. For predicting impacts, the empirical

data from observations during actual structure removals (e.g., Gitschlag et al. 2000)

would seem to be more useful than any attempt to calculate impacts based on

experiments and models. Huge variations in the fish population itself, including

numbers, species, sizes, and orientation and range from the detonation, would make it

very difficult to accurately predict mortalities at any specific site. Since the data

collected by Gitschlag et al. (2000) are limited in terms of depth range and geographic

extent, additional studies may be needed to predict impacts in other areas, including

deepwater environments.

8.2 Sea Turtles

As summarized in Section 6.2, there have been no laboratory studies of explosive

impacts on sea turtles, and only limited field observations and experiments. In several

instances, turtle injuries and mortalities (and in some cases, strandings) have been noted

following underwater detonations. In one case where turtles were recovered after an

open-water detonation, both charge weight and the approximate distances of the turtles

from the detonation were known (O’Keeffe and Young 1984). Only one field experiment

has been conducted in which sea turtles were exposed at known distances from a

structure removal detonation; however, that study did not include concurrent pressure

measurements to estimate the magnitude and duration of the shockwave received by the

caged turtles (Klima et al. 1988). There have been several anecdotal reports of turtle

deaths or strandings following structure removal detonations, including a few in the

15 years since the current mitigation/monitoring requirements were instituted

(G.R. Gitschlag 2003, pers. comm., NOAA-F, Galveston, TX).
157

There have been no mechanistic models developed specifically to estimate

impacts on sea turtles. Rather, it has been assumed that models developed for other

vertebrates are reasonable approximations (Department of the Navy 2001). O’Keeffe and

Young (1984) developed an equation for a turtle “safety range” based on field

observations of three turtles following an open-water detonation. (The “safety range” is

the distance beyond which turtles would not likely be killed or seriously injured.) The

equation is simply based on cube-root scaling of the charge weight and the distance at

which one turtle apparently was not affected. Young (1991) provided a more

conservative version of the same equation but states that it is based on the criteria for

platform removal established by the NMFS – i.e., it was not independently derived from

observations or experimental data. The Department of the Navy (2001) also modeled

effect ranges using the turtle death/injury observations from O’Keeffe and Young (1984)

and a lung injury model developed by Goertner (1982) for small mammals. The results

suggest that lung injury predictions for marine turtles are not inconsistent with

predictions for small mammals.

An important goal with respect to sea turtles is calculating the areal extent of the

mortality/injury zone so that this area can be monitored for turtles prior to detonations. In

the 1988 “generic consultation” for structure removals in the Gulf of Mexico, the NMFS

specified that the area within 3,000 ft (914 m) of the platform must be clear of visible sea

turtles prior to detonation. The NMFS document does not specify the source of this

number, but it apparently is based on the turtle death/injury observations to date (Klima

et al. 1988) rather than any modeling. Klima et al. (1988) reported that of two turtles at

this distance from platform removal detonations, one was normal and the other was

rendered unconscious but appeared normal other than vasodilation around the throat and

flippers.

Years of experience using the 3,000 ft (914 m) range monitored under the

“generic consultation” suggests it has been effective in preventing most deaths or serious

injuries of sea turtles (Gitschlag and Herczeg 1994; Gitschlag et al. 1997). In addition,

the modeling analysis done by the Department of the Navy (2001), while not directly

addressing the “safety range” for structure removals, suggests that the monitoring range

specified in the “generic consultation” is likely to prevent death and lung injury to sea

turtles. However, the empirical and theoretical basis for this specific number is weak.

Although additional experiments with turtles and underwater explosives are unlikely,

some knowledge gained from marine mammal studies in recent years may be applicable.

It is recommended that existing data be reviewed and modeling conducted to calculate

mortality/injury ranges for sea turtles using standard sound level metrics and

incorporating detonation characteristics appropriate for offshore structure removals. This

would provide a firmer foundation for a turtle “safety range.”

8.3 Marine Mammals

As summarized in Section 6.3, only recently have experimental studies of

explosive impacts on marine mammals been conducted, using animal carcasses (Myrick

et al. 1990a; Ketten et al. 2003; Reidenberg and Laitman 2003). For many years, the only

data available for predicting blast impacts on marine mammals were extrapolations from
158

experiments on terrestrial mammals submerged in ponds (Richmond et al. 1973;

Yelverton et al. 1973) and opportunistic post-mortem examinations of stranded animals

following detonations (Ketten 1995).

There have been numerous attempts to model explosive impacts on marine

mammals (Hill 1978; Goertner 1982; O’Keeffe and Young 1984; Young 1991; Ketten

1995; Department of the Navy 2001). Most of the research has focused on larger

explosions associated with military testing such as ship shock trials. There also has been

considerable research into sublethal auditory effects such as TTS and PTS (Ridgway et

al. 1997; Finneran et al. 2000; Schlundt et al. 2000; Nachtigall et al. 2003), as well as

behavioral responses to underwater noise. Much of the behavioral research has focused

on seismic surveys using airguns rather than explosives (Richardson et al. 1995). Both

blast injury and auditory effects are topics of ongoing investigations. Since existing

marine mammal injury models are based on old and very limited data, it is likely that

these models will be refined or new ones developed as more information becomes

available.

For marine mammals as well as sea turtles, an important goal is calculating the

likely extent of mortality and injury zones so that this area can be monitored for the

presence of animals prior to detonations. Both the 1995 and 2002 regulations issued by

the NMFS for incidental take of bottlenose and spotted dolphins in the Gulf of Mexico

specified a “safety range” of 3,000 ft (914 m). This range for marine mammals is not

based on any independent observations or modeling, but is simply the same range used

for sea turtles under the “generic consultation” under Section 7 of the ESA (Federal

Register 67 [148]:49,869-49,875).

Years of experience using the 3,000 ft (914 m) range monitored under the

“generic consultation” suggests it has been effective in preventing most deaths or serious

injuries of marine mammals (Gitschlag and Herczeg 1994; Gitschlag et al. 1997).

However, as noted previously for sea turtles, the basis for this specific number is weak,

and it was not even developed specifically for marine mammals. As additional data for

blast injury in marine mammals become available and new or refined models are

developed, it is recommended that mortality/injury zones be calculated for marine

mammals using standard sound level metrics and incorporating detonation characteristics

appropriate for offshore structure removals. This would provide a firmer foundation for a

marine mammal “safety range.”

Auditory effects such as TTS and PTS may occur beyond the “safety range”

monitored during structure removals. These effects are of particular concern for marine

mammals because of the regulatory implications of the MMPA, which prohibits

“harassment.” In various regulations for ship shock trial and seismic surveys, NOAA-F

(previously NMFS) has accepted TTS as a criterion for marine mammal harassment.

This is an area of ongoing research in which criteria are being developed and refined.

The MMS should coordinate with NOAA-F to make use of the most recent findings and

criteria in evaluating auditory impacts on marine mammals.
159

8.4 Physics of Underwater Detonations

As discussed in Chapter 4, the understanding of the physical principles of

underwater detonations and of the propagation of shock and sonic waves in the

surrounding medium is in itself quite well developed. There are, however, significant

gaps in the application of this knowledge to actual removal of offshore structures. The

containment effect provided by setting the structure-cutting charges below a minimum

prescribed depth of sediment has not been documented for a comprehensive range of

seafloor consistencies, with the result that the extent of the transmission of explosive

energy into the water column may be significantly greater than expected (Nedwell et al.

2001). Much of what is known from experience regarding underwater detonations within

the seafloor comes from rock demolition blasting, which by its very nature is performed

in an altogether different medium from the relatively compliant upper layers of sediment

in which structure-cutting charges are deployed.

A systematic research effort should be undertaken to model numerically the blast

propagation for a range of charge sizes consistent with structure removal practices

through a wide variety of sediment types and for different deployment depths below the

sediment surface. Such modeling should extend to the transfer of energy into the water

column both from the shock wave propagating through the interface and later decaying

into an acoustic signal, and from the oscillating bubble of detonation gases when

breakout into the water does take place. Experimental validation of model results at

every possible opportunity should form an integral part of the study; this requires

accurate measurement of acoustic levels, and preferably full waveform recording, at one

or more locations in the water columns as well as characterization of the sediment

firmness near the structures being removed, which could be done by penetrometer

probing or similar techniques.

Once a reliable modeling approach has been generated and validated, forecasting

of the acoustic levels distribution for planned operations would become possible from the

type and location of the charge to be exploded, the depth of the water column, and the

measured properties of the sediment in which the detonation occurs. In combination with

improved estimation of impact thresholds based on appropriate and standardized sound

metrics for marine mammals and turtles, such a modeling-based assessment of each

planned decommissioning operation involving explosive removal of underwater

structures would provide the best ability to minimize its repercussions on marine life.
161

CHAPTER 9

CONCLUSIONS

The most commonly used technique for explosive cutting of piles and conductors

is with bulk explosive charges. Other techniques such as ring charges, focusing charges,

linear shaped charges, and cutting tape are used in some instances. Increased use of

techniques that involve smaller charge sizes could reduce potential impacts on marine

life.

The physical principles of underwater detonations and of the propagation of shock

and sonic waves in the surrounding medium are well understood, but there are significant

gaps in applying this knowledge to actual removal of offshore structures. It is

recommended that a research effort be undertaken to model numerically blast

propagation for a range of charge sizes consistent with structure removal practices

through a variety of sediment types and for different deployment depths below the

sediment surface. Experimental validation of model results should form an integral part

of the study. Ultimately, forecasting of the acoustic levels distribution for planned

operations would become possible from the type and location of the charge to be

exploded, the depth of the water column, and the measured properties of the sediment in

which the detonation occurs.

Environmental data concerning platform removals serve two main purposes: 1) to

allow impacts to be estimated (e.g., numbers of animals that may be killed or injured

during structure removals); and 2) to aid in developing or refining mitigation measures

that prevent or reduce the likelihood of impacts. Impact estimation is the main goal with

respect to fishes, whereas for sea turtles and marine mammals, mitigation is the main goal

(i.e., predicting the areal extent of mortality and injury zones so that these can be

monitored prior to detonation to prevent impacts).

There are important differences among fishes, sea turtles, and marine mammals

with respect to the types and adequacy of data available. In general, fishes are the beststudied group, and sea turtles the least studied. Effects of underwater explosions on

fishes have been studied and modeled extensively, and field studies have quantified fish

kills associated with structure removals in the Gulf of Mexico. For sea turtles, there have

been no laboratory studies of blast injury, only limited field observations and

experiments, and no mechanistic models developed specifically to estimate impacts. For

many years, the main data available for predicting both blast and auditory impacts on

marine mammals were extrapolations from terrestrial mammal studies, but ongoing

studies are underway that will aid in developing improved mortality, injury, and auditory

impact criteria.

For predicting impacts on fishes, the empirical data from observations during

actual structure removals would seem to be more useful than any attempt to calculate

impacts based on experiments or mechanistic models. Since existing observations
162

(Gitschlag et al. 2000) cover a limited geographic and water depth range, additional

observations will be needed to better estimate future impacts.

Years of experience using the 3,000 ft (914 m) “safety range” monitored under

the “generic consultation” suggest it has been effective in preventing most deaths and

serious injuries of sea turtles and marine mammals. However, the empirical and

theoretical basis for this specific number is weak. It is recommended that

mortality/injury zones be calculated for sea turtles and marine mammals using standard

sound level metrics and incorporating detonation characteristics appropriate for offshore

structure removals. This would provide a firmer foundation for sea turtle and marine

mammal “safety ranges.”

In all three groups, there is relatively little information about sublethal impacts,

particularly on the auditory system. While mitigation measures appear to be effective in

preventing death or injury of mammals and turtles, it is uncertain to what extent sublethal

effects may be occurring beyond the safety range. Recent and ongoing studies may

provide the basis for estimating auditory impacts in marine mammals, which are

particularly important in the regulatory context of “harassment” under the MMPA. There

is almost no information to estimate auditory impacts on sea turtles.

The time interval between shots may be an important mitigation measure. The

amount of time for an animal to recover from a shock wave is unknown. Do closely

spaced shock waves, each of which is insufficient to cause damage, cause damage in

proportion to the sum of the damage parameters or a sum of a time dependent percentage

of damage parameters? The effect of short time intervals between blasts such as those

used in Gulf of Mexico structure removals have not been addressed.

The ONR is conducting research on physical and auditory effects of blast

parameters on marine mammals and detection of marine mammals with passive acoustic

devices. Synergy between MMS and ONR in these areas of research would be fruitful.

The Department of the Navy, Naval Surface Warfare Center is measuring actual blast

parameters in the sea and working on new and/or revisions to blast propagation models.

Synergy with this group would also be fruitful.

To date, mitigation and monitoring requirements for structure removals in the

Gulf of Mexico have focused on sea turtles, bottlenose dolphins, and spotted dolphins.

As structures are removed in greater water depths, many more species of marine

mammals are likely to be encountered, including one endangered species (sperm whale)

and other deep-diving species (such as beaked whales) that pose challenges for detection.

Passive acoustic monitoring could aid in the detection of sperm whales. Not enough is

known about the vocal behavior of beaked whales and some other species to determine

the probability of their being detected by passive acoustic monitoring.
163 

CHAPTER 10 

LITERATURE CITED 

Ahroon, W.A., R.P. Hamernik, and S.F. Lei. 1996. The effects of reverberant blast waves 

on the auditory system. J. Acoust. Soc. Am. 100(4, Pt. 1):2,247-2,257. 

Akamatsu, T., Y. Hatakeyama, and N. Takatsu. 1993. Effects of pulsed sounds on escape 

behavior of false killer whales. Nippon Suisan Gakkaishi 59(8):1,297-1,303. 

Alaska Department of Fish and Game. 2002a. ADF&G’s Wildlife Notebook Series: Sea 

Otter. http://www.state.ak.us/adfg/notebook/marine/seaotter.htm. 

Alaska Department of Fish and Game. 2002b. ADF&G’s Wildlife Notebook Series: 

Beluga Whale. http://www.state.ak.us/adfg/notebook/marine/beluga.htm. 

Alaska Department of Fish and Game. 2002c. ADF&G’s Wildlife Notebook Series: 

Harbor Seal. http://www.state.ak.us/adfg/notebook/marine/harseal.htm. 

Alaska Department of Fish and Game. 2002d. ADF&G’s Wildlife Notebook Series: 

Steller’s Sea Lion. http://www.state.ak.us/adfg/notebook/marine/sealion.htm. 

Alcala, A.C. and E.D. Gomez. 1987. Dynamiting coral reefs for fish: A 

resource-destructive fishing method. Pp. 51-60. In: B. Salvat (ed.). Human 

impacts on coral reefs: Facts and recommendations. French Polynesia: Antenne 

Museum E.P.H.E. 

Al-Hassani, S.T.S. 1988. Platform removal demands complex explosive designs. Oil 

and Gas Journal, 16 May 1988. Pp. 35-39. 

Alpin, J.A. 1947. The effect of explosives on marine life. Cal. Fish and Game 33:23-30. 

American Cetacean Society. 2003a. American Cetacean Society Fact Sheet: Right 

Whale. http://69.5.22.59/factpack/RightWhale.htm. 

American Cetacean Society. 2003b. American Cetacean Society Fact Sheet: Gray 

Whale. http://www.acsonline.org/factpack/graywhl.htm. 

Andersen, P. and S. Løken. 1968. Lung damage and lethality by underwater detonations. 

Acta Physiologica Scandinavica 72:6-14. 

Andersen, S. 1970. Auditory sensitivity of the harbour porpoise Phocoena phocoena. 

Invest. Cetacea 2:255-259. 

Angliss, R.P. and K.L. Lodge. 2002. Alaska marine mammal stock assessments, 2002. 

U.S. Dept. of Commerce, NOAA Tech. Memo. NMFS-AFSC-133. 224 pp. 

Au, W.L., P.E. Nachtigall, and J.L. Pawloski. 1999. Temporary threshold shift in hearing 

induced by an octave band of continuous noise in the bottlenose dolphin. J. Acoust. 

Soc. Am. 106(4, Pt. 2):2,251. 

Baird, I.G., B. Mounsouphom, and P.J. Stacey. 1994. Preliminary surveys of Irrawaddy 

dolphins (Orcella brevirostris) in Lao PDR and northeastern Cambodia. Rep. Int. 

Whal. Comm. 44:367-369. 

Barlow, J. 1994. Abundance of large whales in California coastal waters: A comparison of 

ship surveys in 1979/80 and in 1991. Rept. Int. Whal. Comm. 44:399-406. 
164 

Barlow, J. 1997. Preliminary estimates of cetacean abundance off California, Oregon, and 

Washington based on a 1996 ship survey and comparisons of passing and closing 

modes. Available from Southwest Fisheries Science Center, P.O. Box 271, La 

Jolla, CA. Admin. Rept. LJ-97-11. 25 pp. 

Bartol, S.M. and D. Ketten. 2003. Auditory brainstem responses of multiple species of 

sea turtles. p. 29. In: R. Gisner (ed.). Environmental Consequences of 

Underwater Sound (ECOUS) Abstracts, 12-16 May 2003, San Antonio, TX. 

Office of Naval Research, Arlington, VA. 86 pp. 

Bartol, S.M. and J.A. Musick. 2003. Sensory biology of sea turtles. Pp. 79-102. In: P.L. 

Lutz, J.A. Musick, and J. Wyneken (eds.). The Biology of Sea Turtles, Volume II. 

Boca Raton, FL: CRC Press. 

Bartol, S.M., J.A. Musick, and M.L. Lenhardt. 1999. Auditory evoked potentials of the 

loggerhead sea turtle (Caretta caretta). Copeia 3:836-840. 

Baxter II, L. 1985. Mortality of fish subjected to explosive shock as applied to oil well 

severance on Georges Bank. Pp. 119-134. In: C.D. Greene, F.R. Englehardt, and 

R.J. Paterson (eds.). Proceedings of the workshop on effects of explosives in the 

marine environment, 29-31 January 1985, Halifax. Can. Oil and Gas Lands 

Admin., Environ. Prot. Br., Ottawa, Ont. Tech. Rep. No. 5. 

Baxter II, L., E.E. Hays, G.R. Hampson, and R.H. Backus. 1982. Mortality of fish 

subjected to explosive shock as applied to oil well severance on Georges Bank. 

Woods Hole Oceanographic Institution, Woods Hole, MA. Tech. Rep. 

WHOI-82-54. 

Bayley, P.B. and D.J. Austen. 1988. Comparison of detonating cord and rotenone for 

sampling fish in warmwater impoundments. North American Journal of Fisheries 

Management 8(3):310-316. 

Blackburn, J.E., K. Anderson, C.I. Hamilton, and S.J. Staff. 1979. Pelagic and demersal 

fish assessment in the lower Cook Inlet estuary system. Final report from Alaska 

Department of Fish and Game to NOAA/OSCEAP. 330 pp. 

Bohne, B.A., J.A. Thomas, E.R. Yohe, and S.H. Stone. 1985. Examination of potential 

hearing damage in Weddell seals (Leptonychotes weddelli) in McMurdo Sound, 

Antarctica. Antarct. J. U.S. 20:174-176. 

Bohne, B.A., D.G. Bozzay, and J.A. Thomas. 1986. Evaluation of inner ear pathology in 

Weddell seals. Antarct. J. U.S. 21:208. 

Boland, G.S. 2002. Fish and epifaunal community observations at an artificial reef near 

a natural coral reef: Nineteen years at Platform High Island A389-A, from bare 

steel to coral habitat. Pp. 372-392. In: M. McKay, J. Nides, and D. Vigil (eds.). 

Proceedings: Gulf of Mexico fish and fisheries: Bringing together new and recent 

research, October 2000. U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study 

MMS 2002-004. 674 pp. 

Booth, J. and K.A. Peters. 1972. Behavioural studies on the green turtle (Chelonia 

mydas) in the sea. Anim. Behav. 20:808-812. 
165 

Bowles, A.E., M. Smultea, B. Würsig, D.P. DeMaster, and D. Palka. 1994. Relative 

abundance and behavior of marine mammals exposed to transmissions for the 

Heard Island feasibility test. J. Acoust. Soc. Am. 96(4):2,469-2,484. 

Brekhovskikh, L.M. 1980. Waves in Layered Media. 2nd ed. New York: Academic 

Press. Pp. 1-59. 

Brown, F.A. 1939. Responses of the swimbladder of the guppy, Lebistes reticulates, to 

sudden pressure decreases. Biological Bulletin 76:48-58. 

Carder, D.A. and S.H. Ridgway. 1990. Auditory brainstem response in a neonatal sperm 

whale, Physeter spp. J. Acoust. Soc. Am. 88(Suppl. 1):S4. 

Carr, A. 1996. A Naturalist in Florida: A Celebration of Eden. New Haven: Yale 

University Press. 

Carr, A.F. 1954. The passing of the fleet. Am. Inst. Biol. Sci. Bull. 4(5):17-19. 

Carretta, J.V., M.M. Muto, J. Barlow, J. Baker, K.A. Forney, and M. Lowry. 2002. U.S. 

Pacific marine mammal stock assessments: 2002. NOAA Tech. Memo. NMFS, 

NOAA-TM-SWFSC-346. 

Cassano, E.R., A.C. Myrick, Jr., C.B. Glick, R.C. Holland, and C.E. Lennert. 1990. The 

use of seal bombs in the yellowfin tuna purse-seine fishery. U.S. Natl. Mar. Fish. 

Serv., La Jolla, CA. Admin. Rep. LJ-90-09. 31 pp. 

Cavanagh, R.C. 2000. Criteria and thresholds for adverse effects of underwater noise on 

marine animals. Report by Science Applications International Corp., McLean, VA 

for U.S. Air Force, Air Force Research Laboratory. Wright-Patterson AFB, Ohio. 

Contract F41624-96-C-9005. 

Christian, E.A. 1973. The effects of underwater explosions on swimbladder fish. Naval 

Ordnance Laboratory, White Oak, Silver Spring, MD. NOLTR 73-103. 33 pp. 

Cole, R.H. 1948. Underwater explosions. Princeton, NJ: Princeton University Press. 

437 pp. 

Connor, J.G., Jr. 1990. Underwater blast effects from explosive severence of offshore 

platform legs and well conductors. Naval Surface Warfare Center, Silver Spring, 

MD. NAVSWC-TR-90-532. 146 pp. 

Continental Shelf Associates, Inc. 1982. Study of the effect of oil and gas activities on 

reef fish populations in the Gulf of Mexico OCS area. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

OCS Report MMS 82-10. 

Continental Shelf Associates, Inc. 2002. Geological and geophysical exploration for 

minerals resources on the Gulf of Mexico outer continental shelf: Draft 

programmatic environmental assessment. Prepared for the U.S. Dept. of the 

Interior, Minerals Management Service, Gulf of Mexico OCS Region, New 

Orleans, LA. 

Craig, J.C. and C.W. Hearn. 1998. Physical impacts of explosions on marine mammals 

and turtles. Appendix D, Final environmental impact statement: Shock testing the 

SEAWOLF submarine. Naval Surface Warfare Center, Carderock Division, 

Bethesda, MD. 42 pp. 
166 

Craig, J.C., Jr. 2001. Physical impacts of explosions on marine mammals and turtles. 

Appendix D, Final environmental impact statement: Shock trial of the WINSTON 

S. CHURCHILL (DDG 81). Naval Surface Warfare Center, Carderock Division, 

Bethesda, MD. 43 pp. 

Cummings, W.C., J.M. Holzmann, and P.O. Thompson. 1975. Underwater sound 

pressure minima in bioacoustic test tanks. NUC TP 450. U.S. Naval Undersea 

Cent., San Diego, CA. NTIS AD-A032768. 40 pp. 

Dailey, M.D., D.J. Reish, and J.W. Anderson (eds.). 1993. Ecology of the Southern 

California Bight - A Synthesis and Interpretation. Berkeley, CA: University of 

California Press. 926 pp. 

Davis, R.W., W.E. Evans, and B. Würsig (eds.). 2000. Cetaceans, sea turtles and 

seabirds in the northern Gulf of Mexico: Distribution, abundance and habitat 

associations, Vol. II: Technical report. U.S. Dept. of the Interior, Geological 

Survey, Biological Resources Division, USGS/BRD/CR-1999-0006, and Minerals 

Management Service, New Orleans, LA. OCS Study MMS 2000-003. 

Demarchi, M.W., W.B. Griffiths, D. Hannay, R. Racca, and S. Carr. 1998. Effects of 

military demolitions and ordnance disposal on selected marine life in marine 

training and exercise area WQ. Report by LGL Limited, Environmental Research 

Associates, Sidney, BC and Jasco Research Ltd., Sidney, BC for the Department 

of National Defense, CFB Esquimalt, Esquimalt, BC. 

DEMEX. 2002. Explosive technology report for structure removals in the Gulf of 

Mexico. Draft. DEMEX, Division of TEi Construction Services, Inc. 

Department of the Navy. 1998. Final environmental impact statement: Shock testing the 

SEAWOLF submarine. Department of the Navy, Southern Division, Naval 

Facilities Engineering Command, North Charleston, SC. var. pp. 

Department of the Navy. 2001. Shock Trial of the WINSTON S. CHURCHILL 

(DDG 81): Final environmental impact statement, February 2001. Prepared by 

Continental Shelf Associates, Inc. 

Department of the Navy. 2002. Final Environmental Impact Statement/Overseas 

Environmental Impact Statement - Point Mugu Sea Range. March 2002. Naval 

Air Warfare Center Weapons Division, Pt. Mugu, CA. 

Dick, R.A., D.V. D’Andrea, and L.R. Fletcher. 1993. Back to basics: Properties of 

explosives. Journal of Explosive Engineering 10(6):28-45. 

Edwards, R.E., K.J. Sulak, and D. Weaver. 2002. Deepwater petroleum structures as 

fish aggregating devices: An in-progress project report. Pp. 50-64. In: M. 

McKay, J. Nides, and D. Vigil (eds.). Proceedings: Gulf of Mexico fish and 

fisheries: Bringing together new and recent research, October 2000. U.S. Dept. of 

the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New 

Orleans, LA. OCS Study MMS 2002-004. 674 pp. 

Egloff, M. 1996. Failure of swim bladder inflation of perch, Perca fluvitilis L., found in 

natural populations. Aquatic Sciences 58(1):17-23. 

Ernst, C.H., J.E. Lovich, and R.W. Barbour. 1994. Turtles of the United States and 

Canada. Washington, DC: Smithsonian Institute Press. 578 pp. 
167 

Ferguson, R.G. 1962. The effects of underwater explosions on yellow perch. Can. Fish. 

Cult. 29:31-39. 

Finneran, J.J. 2003. A TTS-based damage risk model for marine mammals. p. 77. In: 

R. Gisner (ed.). Environmental consequences of underwater sound, 12-16 May, 

2003. Office of Naval Research, Life Sciences Research Office, Bethesda, MD. 

Finneran, J.J., C.E. Schulundt, D.A. Carder, J.A. Clark, J.A. Young, J.B. Gaspin, and S.H. 

Ridgway. 2000. Auditory and behavioral responses of bottlenose dolphins 

(Tursiops truncatus) and a beluga whale (Delphinapterus leucas) to impulsive 

sounds resembling distant signatures of underwater explosions. J. Acoust. Soc. 

Am. 108(1):417-431. 

Finneran, J.J., C.E. Schlundt, R. Dear, D.A. Carder, and S.H. Ridgway. 2002. Temporary 

shift in masked hearing thresholds in odontocetes after exposure to single 

underwater impulses from a seismic watergun. J. Acoust. Soc. Am. 

111(6):2,929-2,940. 

Fish, J.F. and J.S. Vania. 1971. Killer whale, Orcinus orca, sounds repel white whales, 

Delphinapterus leucas. Fish. Bull. 69(3):531-535. 

Fitch, J.E. and P.H. Young. 1948. Use and effect of explosives in California coastal 

waters. Calif. Fish and Game 34:53-70. 

Fleming, E.H. 2001. Swimming against the tide: Recent surveys of exploitation, trade, 

and management of marine turtles in the northern Caribbean. TRAFFIC North 

America. 161 pp. 

Frost, K.J., L.F. Lowrey, and R.R. Nelson. 1984. Belukha whale studies in Bristol Bay 

Alaska. Pp. 187-200. In: B.R. Melteff and D.H. Rosenberg (eds.). Proceedings: 

Workshop on biological interactions among marine mammals and commercial 

fisheries in the southeastern Bering Sea, Oct. 1983, Anchorage, AK. Univ. of 

Alaska, Fairbanks, AK. Univ. of Alaska Sea Grant Rep. 84-1. 

Fry, D.H. and K.W. Cox. 1953. Observations on the effects of black powder explosions 

on fish life. Cal. Fish and Game 39(2):233-236. 

Fuller, D.A. and A.M. Tappan. 1986. The occurrence of sea turtles in Louisiana coastal 

waters. Center for Wetland Resources, Louisiana State University, Baton Rouge, 

LA. Unpublished report, LSU-CFI-86-28. 

Fuller, R.G. and J.B. Kirkwood. 1977. Ecological consequences of nuclear testing. 

p. 682. In: M.L. Merrit and R.G. Fuller (eds.). The environment of Amchitka 

Island, Alaska. Energy Res. & Devel. Admin., Springfield, VA. NTIS TID-26712. 

Gallaway, B.J. and G.S. Lewbel. 1982. The ecology of petroleum platforms in the 

northwestern Gulf of Mexico: A community profile. U.S. Dept. of the Interior, 

Fish and Wildlife Service, Office of Biological Services, FWS/OBS-82/27. 

92 pp. 

Gaspin, J.B. 1975. Experimental investigations on swimbladder fish. I: Chesapeake Bay 

tests. Naval Surface Weapons Center, Silver Spring, MD. Final Report 

NSWC/WOL.TR 75-58. 

Gaspin, J.B. 1983. Safe swimmer ranges from bottom explosions. Naval Surface 

Weapons Center, White Oak Lab, Def. Tech. Info. Cent., Silver Spring, MD. 

NSWC/WOL.TR-83-84. 
168 

Geraci, J.R. and D.J. St. Aubin. 1985. Effects of offshore oil and gas development on 

marine mammals and turtles. Pp. 12-1 to 12-34. In: D.F. Boesch and N.N. 

Rabalais (eds.). The Long-term Effects of Offshore Oil and Gas Development: 

An Assessment and a Research Strategy. A Final Report to the National Marine 

Pollution Office, National Oceanic and Atmospheric Administration, Rockville, 

MD. 

Gisner, R.C. (ed.). 1998. Workshop on the effects of anthropogenic noise in the marine 

environment, 10-12 February 1998. Marine Mammal Science Program, Office of 

Naval Research, Arlington, VA. 141 pp. 

Gitschlag, G.R. 1990. Sea turtle monitoring at offshore oil and gas platforms. In: T.H. 

Richardson, J.I. Richardson, and M. Donnelly (comps.). Proceedings of the Tenth 

Annual Workshop on Sea Turtle Biology and Conservation, 20-24 February 1990, 

Hilton Head, South Carolina. NOAA Tech. Memo. NMFS-SEFSC-278. 233 pp. 

Gitschlag, G.R. and B.A. Herczeg. 1994. Sea turtle observations at explosive removals 

of energy structures. Mar. Fish. Rev. 56(2)1-8. 

Gitschlag, G.R. and M. Renaud. 1989. Sea turtles and the explosive removal of offshore 

oil and gas structures. Pp. 67-68. In: S.A. Eckert, K.L. Eckert, and T.H. 

Richardson (comps.). Proceedings of the Ninth Annual Workshop on Sea Turtle 

Conservation and Biology. NOAA Tech. Memo. NMFS-SEFSC-232. 

Gitschlag, G.R., B.A. Herczeg, and T.R. Barcak. 1997. Observations of sea turtles and 

other marine life at the explosive removal of offshore oil and gas structures in the 

Gulf of Mexico. Gulf Res. Rep. 9(4):247-262. 

Gitschlag, G.R., M.J. Schirripa, and J.E. Powers. 2000. Estimation of fisheries impacts 

due to underwater explosives used to sever and salvage oil and gas platforms in 

the U.S. Gulf of Mexico: Final report. U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Study MMS 2000-087. 80 pp. 

Glass, K. 1989. Are dolphins being deafened in the Pacific? Oceanus 32(4):83-85. 

Goertner, J.F. 1982. Prediction of underwater explosion safe ranges for sea mammals. 

Naval Surface Weapons Center, Silver Spring, MD. NSWC/WOL TR 82-188. 

NTIS ADA 139823. 25 pp. 

Goertner, J.F., M.L. Wiley, G.A. Young, and W.W. McDonald. 1994. Effects of 

underwater explosions on fish without swimbladders. Naval Surface Warfare 

Center, Dahlgren Division, White Oak Detachment, Silver Spring, MD. NSWC 

TR 88-114. 

Goold, J.C. 1996. Acoustic assessment of populations of common dolphin Delphinus 

delphis in conjunction with seismic surveying. J. Mar. Biol. Assoc. U.K. 

76:811-820. 

Goold, J.C. and P.J. Fish. 1998. Broadband spectra of seismic survey air-gun emissions, 

with reference to dolphin auditory thresholds. J. Acoust. Soc. Am. 

103(4):2,177-2,184. 
169 

Govoni, J.J., L.R. Settle, and M.A. West. 2002. Investigation of impacts of underwater 

explosions on larval and early juvenile fishes. Part 2: Trauma to late-stage larval 

and early-juvenile pinfish, Lagodon rhomboides, and spot, Leiostomus xanthurus, 

inflicted by sub-marine detonations. Report to U.S. Army Corps of Engineers, 

Wilmington District, Wilmington, NC. 

Greene, C.R., Jr. 1998. Underwater acoustic noise and transmission loss during summer 

at BP’s Liberty prospect in Foggy Island Bay, Alaskan Beaufort Sea. Report from 

Greeneridge Sciences Inc., Santa Barbara, CA, and LGL Ltd., King City, Ontario 

for BP Exploration (Alaska) Inc., Anchorage, AK. Greeneridge Rep. 189-1. 

39 pp. 

Gulf of Mexico Fishery Management Council. 1998. Generic amendment for addressing 

essential fish habitat requirements in the following fishery management plans of 

the Gulf of Mexico: Shrimp fishery of the Gulf of Mexico, United States waters; 

red drum fishery of the Gulf of Mexico; reef fish fishery of the Gulf of Mexico; 

coastal migratory pelagic resources (mackerels) in the Gulf of Mexico and South 

Atlantic; stone crab fishery of the Gulf of Mexico; spiny lobster in the Gulf of 

Mexico and South Atlantic; coral and coral reefs of the Gulf of Mexico (includes 

environmental assessment). U.S. Dept. of Commerce, National Oceanic and 

Atmospheric Administration, Gulf of Mexico Fishery Management Council, 

Tampa, FL, NOAA Award Number NA87FC0003. 

Hadžiselimović, H. and M. Andelić. 1967. Contribution to the knowledge of the ear in 

the sea turtle. Acta. Anat. 66:460-477. 

Hall, J.D. and C.S. Johnson. 1972. Auditory thresholds of a killer whale Orcinus orca

Linnaeus. J. Acoust. Soc. Am. 51(2):515-517. 

Hannay, D.E. 1995. Estimation of geoacoustic parameters of the ocean bottom by 

inversion of reflection loss data. M.S. Thesis, University of Victoria, Victoria, 

BC, Canada. 

Hawkins, A.D. 1986. Underwater sound and fish behavior. Pp. 114-151. In: T. Pitcher 

(ed.). The Behavior of Teleost Fishes. Baltimore, MD: The Johns Hopkins 

University Press. 

Heathcote, T.B. 1981. An experimental program to determine the environmental impact 

of explosive removal of oil wellheads: Progress report. Naval Surface Weapons 

Center, White Oak Lab., Silver Spring, MD. 27 pp. 

Helweg, D.A., J.B. Gaspin, and J.A. Goertner. 1998. Criteria for marine mammal auditory 

threshold shift: Appendix E, Final environmental impact statement: Shock testing 

the SEAWOLF submarine. SPAWARSYSCEN, San Diego, CA. 

Henwood, T. 1988. National Marine Fisheries Service perspective on structure 

removals. Pp. 300-303. In: Minerals Management Service Proceedings: Eighth 

Annual Gulf of Mexico Information Transfer Meeting, December 1987. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico Region, New 

Orleans, LA. OCS Study MMS 88-0035. 

Hill, S.H. 1978. A guide to the effects of underwater shock waves on Arctic marine 

mammals and fish. Institute of Marine Sciences, Patricia Bay, Sidney, BC. 

Pacific Marine Science Report 78-26. 50 pp. 
170 

Hirsch, A.E. and A.K. Ommaya. 1972. Head injury caused by underwater explosion of 

a firecracker. J. Neurosurg. 37(1):95-99. 

Hirth, H.H. 1997. Synopsis of biological data on the green turtle, Chelonia mydas

(Linnaeus 1758). Report to the U.S. Dept. of the Interior, Fish and Wildlife 

Service, Washington, DC. Biological Report 97(1). 120 pp. 

Hooker, S.K. 1999. Resource and habitat use of northern bottlenose whales in the Gully: 

Ecology, diving and ranging behaviour. Ph.D. thesis, Dalhousie University, 

Halifax, NS. 211 pp. 

Hubbs, C.L. and A.B. Rechnitzer. 1952. Report on experiments designed to determine 

effects of underwater explosions on fish life. Calif. Fish and Game 38:333-366. 

Jefferson, T.A. and B.E. Curry. 1994. Review and evaluation of potential acoustic 

methods of reducing or eliminating marine mammal-fishery interactions. Report by 

Marine Mammal Research Program, Texas A&M Univ., College Station, TX for 

Marine Mammal Commission, Washington, DC. NTIS PB 95 100384. 59 pp. 

Johnson, C.S. 1967. Sound detection thresholds in marine mammals. Pp. 247-260. In: 

W.N. Tavolga (ed.). Marine Bio-acoustics, Vol. 2. Oxford, U.K.: Pergamon. 

353 pp. 

Johnson, C.S. 1968. Masked tonal thresholds in the bottlenosed porpoise. J. Acoust. Soc. 

Am. 44(4):965-967. 

Jones, F.R.H. 1951. The swimbladder and vertical movements of teleostean fishes. I. 

Physical factors. J. Exp. Biol. 28:553-566. 

Jones, F.R.H. 1952. The swimbladder and vertical movements of teleostean fishes. II. 

The restriction to rapid and slow movements. J. Exp. Biol. 29:94-109. 

Jones, F.R.H. and N.B. Marshall. 1953. The structure and function of the teleostean 

swimbladder. Biol. Rev. 28:16-83. 

Kaiser, M.J., D.V. Mesyanzhinov, and A.G. Pulsipher. 2002. Explosive removals of 

offshore structures in the Gulf of Mexico. Ocean Coast. Manage. 45(8):459-483. 

Kastak, D., R.J. Schusterman, B.L. Southall, and C.J. Reichmuth. 1999. Underwater 

temporary threshold shift induced by octave-band noise in three species of 

pinniped. J. Acoust. Soc. Am. 106(2):1,142-1,148. 

Keevin, T.M. 1998. A review of Natural Resource Agency recommendations for 

mitigating the impacts of underwater blasting. Reviews in Fish Science 

6(4):281-313. 

Keevin, T.M. and G.L. Hempen. 1997. The environmental effects of underwater 

explosions with methods to mitigate impacts. U.S. Army Corps of Engineers, St. 

Louis, MO. 

Ketten, D.R. 1995. Estimates of blast injury and acoustic trauma zones for marine 

mammals from underwater explosions. Pp. 391-407. In: R.A. Kastelein, J.A. 

Thomas, and P.E. Nachtigall (eds.). Sensory Systems of Aquatic Mammals. 

Woerden, The Netherlands: De Spil Publishers. 
171 

Ketten, D.R. 1998. Marine mammal auditory systems: A study of audiometric and 

anatomical data and its implications for underwater acoustic impacts. U.S. Dept. of 

Commerce, National Oceanic and Atmospheric Administration, Natl. Mar. Fish. 

Serv., Southwest Fisheries Science Center, La Jolla, CA. 

NOAA-TM-NMFS-SWFSC SWFSC-256. 74 pp. 

Ketten, D.R. 2000. Cetacean ears. Pp. 43-108. In: W.W.L. Au, A.N. Popper, and R.R. 

Fay (eds.). Hearing by Whales and Dolphins. New York: Springer-Verlag. 

Ketten, D.R., J. Lien, and S. Todd. 1993. Blast injury in humpback whales ears: Evidence 

and implications. J. Acoust. Soc. Am. 94(3, Pt. 2):1,849-1,850. 

Ketten, D.R., J. Arruda, S. Cramer, J.O. O'Malley, J. Reidenberg, and S. McCall. 2003. 

Experimental measures of blast trauma in marine mammals. p. 30. In: R. Gisner 

(ed.). Environmental consequences of underwater sound, 12-16 May 2003. Office 

of Naval Research, Life Sciences Research Office, Bethesda, MD. 

Klima, E.F., G.R. Gitschlag, and M.L. Renaud. 1988. Impacts of the explosive removal of 

offshore petroleum platforms on sea turtles and dolphins. Mar. Fish. Rev. 

50(3):33-42. 

Konya, C.J. and E.J. Walter. 1985. Seminar on Blasting and Overbreak Control (rock 

blasting). U.S. Department of Transportation, Federal Highway Administration, 

National Technical Information Service, Springfield, VA. 

Koski, W.R., J.W. Lawson, D.H. Thomson, and W.J. Richardson. 1998. Point Mugu sea 

range technical report. Rep. by LGL Limited, King City, ON and Ogden 

Environmental Energy Services, Santa Barbara, CA for U.S. Navy Naval Air 

Warfare Center, Weapons Division, Point Mugu, CA and Southwest Division 

Naval Facilities Engineering Command, San Diego, CA. 281 pp. 

Kryter, K.D. 1985. The Effects of Noise on Man. 2nd ed. Orlando, FL: Academic Press. 

688 pp. 

Kryter, K.D. 1994. The Handbook of Hearing and the Effects of Noise: Physiology, 

Psychology, and Public Health. San Diego, CA: Academic Press. 

Landsberg, P.G. 2000. Underwater blast injuries. Trauma and Emergency Medicine 

17(2). www.scuba-doc.com. 

Larkman, V.E. and R.R. Veit. 1998. Seasonality and abundance of blue whales off 

southern California. CalCOFI Rep. 39:236-239. 

Leatherwood, S. and R.R. Reeves. 1989. Marine mammal research and conservation in Sri 

Lanka 1985-1986. Mar. Mamm. Tech. Rep. 1. United Nations Environ. Prog., 

Oceans & Coastal Areas Prog. Activ. Cent., Nairobi, Kenya. 138 pp. 

Lenhardt, M.L. 1982. Bone conduction hearing in turtles. J. Aud. Res. 22:153-160. 

Lenhardt, M.L. and S.W. Harkins. 1983. Turtle shell as an auditory receptor. J. Aud. 

Res. 23:251-260. 

Lenhardt, M.L., S. Bellmund, R.A. Byles, S.W. Harkins, and J.A. Musick. 1983. Marine 

turtle reception of bone-conducted sound. J. Aud. Res. 23:119-125. 

Lenhardt, M.L., R.C. Klinger, and J.A. Musick. 1985. Marine turtle middle-ear anatomy. 

J. Aud. Res. 25:66-72. 
172 

Lenhardt, M.L., S.E. Moein, J.A. Musick, and D. Barnard. 1994. Evaluation of the 

response of loggerhead sea turtles (Caretta caretta) to a fixed sound source. U.S. 

Army Corps of Engineers Waterways Experiment Station. 15 pp. 

Lewis, J.A. 1996. Effects of underwater explosions on life in the sea. Defense Science 

and Technology Organization, Aeronautical and Maritime Research Laboratory, 

Melbourne. DSTO-GD-0080. 39 pp. 

Liem, K.F. 1988. Form and function of lungs: The evolution of air breathing 

mechanisms. Am. Zool. 28:739-759. 

Lien, J., S. Todd, P. Stevick, F. Marques, and D. Ketten. 1993. The reaction of humpback 

whales to underwater explosions. J. Acoust. Soc. Am. 94(3, Pt. 2):1,849. 

Linton, T.S., A.M. Landry, Jr., J.F. Buckner, Jr., and R.L. Berry. 1985. Effects upon 

selected marine organisms of explosives used for sound production in geophysical 

exploration. T. Journal of Science 37:341-353. 

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers. 1989. Are sea turtles 

attracted to petroleum platforms? Pp. 103-104. In: S.A. Eckert, K.L. Eckert, and 

T.H. Richardson (comps.). Proceedings of the Ninth Annual Workshop on Sea 

Turtle Conservation and Biology, 7-11 February 1989, Jekyll Island, Georgia. 

NOAA Tech. Memo. NMFS-SEFSC 232. 

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers. 1990. Association of 

sea turtles with petroleum platforms in the north-central Gulf of Mexico. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Regional Office, New Orleans, LA. OCS Study MMS 90-0025. 90 pp. 

Love, M., J. Hyland, A. Ebling, T. Herrlinger, A. Brooks, and E. Imamura. 1994. A 

pilot study of the distribution and abundances of rockfishes in relation to natural 

environmental factors and an offshore oil and gas production platform off the 

coast of southern California. Bull. Mar. Sci. 55:1,062-1,085. 

Love, M.S., M. Nishimoto, D. Schroeder, and J. Caselle. 1999. The ecological role of 

natural reefs and oil and gas production platforms on rocky reef fishes in southern 

California: Final interim report. U.S. Department of the Interior, U.S. Geological 

Survey, Biological Resources Division, USGS/BRD/CR-1999-007. 208 pp. 

Love, M.S., J.E. Caselle, and L. Snook. 2000. Fish assemblages around seven oil and 

gas platforms in the Santa Barbara Channel area. Fish. Bull. 98(1):96-117. 

Love, M.S., M. Nishimoto, and D. Schroeder. 2001. The ecological role of natural reefs 

and oil and gas production platforms on rocky reef fishes in southern California: 

1998-1999 survey report. U.S. Department of the Interior, U.S. Geological 

Survey, Biological Resources Division, Seattle, Washington 98104, OCS Study 

MMS 2001-028. 115 pp. 

MacGillivray, A.O., D.E. Hannay, and S.A. Carr. 2002. Acoustic Monitoring Results 

from the Anderson Resources 2001 Beaufort Sea Marine Seismic Program. 

December 2002. JASCO Research Ltd. 

MacGillivray, A.O., M.E. Austin, and D.E. Hannay. 2003. Acoustic Monitoring of 

WesternGeco 2002 Mackenzie River Seismic Project. Report for WesternGeco 

Ltd. by JASCO Research Ltd. 
173 

Madsen, P.T., B. Mohl, B.K. Nielsen, and M. Wahlberg. 2002. Male sperm whale 

behaviour during exposures to distant seismic survey pulses. Aquat. Mamm. 

28(3):231-240. 

Malme, C.I., and P.R. Miles. 1985. Behavioral responses of marine mammals (gray 

whales) to seismic discharges. Pp. 253-280. In: G.D. Greene, F.R. Engelhardt, and 

R.J. Paterson (eds.). Proceedings: Workshop on effects of explosives use in the 

marine environment, January, 1985, Halifax, NS. Can. Oil & Gas Lands Admin., 

Environ. Prot. Br., Ottawa, Ont. Tech. Rep. No. 5. 398 pp. 

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird. 1983. Investigations of the 

potential effects of underwater noise from petroleum industry activities on 

migrating gray whale behavior. Report from Bolt Beranek & Newman Inc., 

Cambridge, MA for U.S. Minerals Management Service, Anchorage, AK. NTIS 

PB86-174174. BBN Rep. 5366. var. pp. 

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird. 1984. Investigations of the 

potential effects of underwater noise from petroleum industry activities on 

migrating gray whale behavior/Phase II: January 1984 migration. Report from Bolt 

Beranek & Newman Inc., Cambridge, MA for U.S. Minerals Management Service, 

Anchorage, AK. NTIS PB86-218377. BBN Rep. 5586. var. pp. 

Malme, C.I., B. Würsig, J.E. Bird, and P. Tyack. 1988. Observations of feeding gray 

whale responses to controlled industrial noise exposure. Pp. 55-73. In: W.M. 

Sackinger, M.O. Jeffries, J.L. Imm, and S.D. Treacy (eds.). Port and Ocean 

Engineering Under Arctic Conditions, Vol. II. Geophys. Inst., Univ. Alaska, 

Fairbanks, AK. 

Marquez, R.M. 1990. FAO species catalog. Vol. 11: Sea turtles of the world. An 

annotated and illustrated catalog of sea turtle species known to date. FAO, Rome: 

FAO Fisheries Synopsis, No. 125, Vol. 11. 81 pp. 

Mate, B.R., K.M. Stafford, and D.K. Ljungblad. 1994. A change in sperm whale (Physter 

macrocephalus) distribution correlated to seismic surveys in the Gulf of Mexico. J. 

Acoust. Soc. Am. 96(5, Pt. 2):3,268-3,269. 

McCauley, R.D., M.N. Jenner, C. Jenner, K.A. McCabe, and J. Murdoch. 1998. The 

response of humpback whales (Megaptera novaeangliae) to offshore seismic 

survey noise: Preliminary results of observations about a working seismic vessel 

and experimental exposures. APPEA J. 1998:28-43. 

McCauley, R.D., J. Fretwell, A.J. Duncan, C. Jenner, M.N. Jenner, J.D. Penrose, R.I.T. 

Prince, A. Adhitya, J. Murdoch, and K.A. McCabe. 2000. Marine seismic 

surveys - A study of environmental implications. APPEA J. 40:692-708. 

McCauley, R.D., J. Fretwell, and A.N. Popper. 2003. High intensity anthropogenic 

sound damages fish ears. J. Acoust. Soc. Am. 113(1):638-642. 

McManus, J.W., R.B. Reyes, and C.L. Nañola. 1997. Effects of some destructive fishing 

methods on coral cover and potential rates of recovery. Environmental 

Management 21(1):69-78. 

Mecklenburg, C.W., T.A. Mecklenburg, and L.K. Thorsteinson. 2002. Fishes of Alaska. 

American Fisheries Society, Bethesda, MD. 1,037 pp. 
174 

Metzger, R.J. and P.L. Shafland. 1986. Use of detonating cord for sampling fish. North 

American Journal of Fisheries Management 6:113-118. 

Miller, G.W., R.E. Elliott, W.R. Koski, V.D. Moulton, and W.J. Richardson. 1999. 

Whales (1998). Pp. 5-1 to 5-109. In: W.J. Richardson (ed.). Marine mammal 

and acoustical monitoring of Western Geophysical’s open-water seismic program 

in the Alaskan Beaufort Sea, 1998. Rep. from LGL Ltd., King City, Ont., and 

Greeneridge Sciences Inc., Santa Barbara, CA, for Western Geophysical, 

Houston, TX, and U.S. Natl. Mar. Fish. Serv., Anchorage, AK, and Silver Spring, 

MD. LGL Rep. TA2230-3. 390 pp. 

Miller, J.D. 1997. Reproduction in sea turtles. Pp. 51-82. In: P.L. Lutz and J.A. Musick 

(eds.). The Biology of Sea Turtles. Boca Raton, FL: CRC Press. 

Minerals Management Service. 1987. Structural removal activities, Central and Western 

Gulf of Mexico Planning Areas - Programmatic environmental assessment. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. OCS EIS/EA MMS 87-0002. 

Minerals Management Service. 1996. Cook Inlet Planning Area Oil and Gas Lease Sale 

149, Final Environmental Impact Statement. U.S. Dept. of Interior, Minerals 

Management Service, Alaska OCS Region. 

Minerals Management Service and California State Lands Commission. 1997. 

Decommissioning and removal of oil and gas facilities offshore California: 

Recent experiences and future deepwater challenges. Proceedings of a Public 

Workshop, 23-25 September 1997, Ventura, CA. 196 pp. 

Moein, S., M. Lenhardt, D. Barnard, J. Keinath, and J. Musick. 1993. Marine turtle 

auditory behavior. J. Acous. Soc. Am. 93(4, Pt. 2):2,378. 

Moein, S.E., J.A. Musick, and M.L. Lenhardt. 1994. Auditory behavior of the 

loggerhead sea turtle (Caretta caretta). p. 89. In: K.A. Bjorndahl, A.B. Bolten, 

D.A. Johnson, and P.J. Eliazar (comps.). Proceedings of the Fourteenth Annual 

Symposium on Sea Turtle Biology and Conservation, NOAA Tech. Memo. 

NMFS-SEFSC-351. 

Moein, S.M. 1994. Auditory evoked potentials of the loggerhead sea turtle (Caretta 

caretta). M.S. Thesis, College of William and Mary. 66 pp. 

Mueter, F.J. and B.L. Norcross. 2002. Spatial and temporal patterns in the demersal fish 

community on the shelf and upper slope regions of the Gulf of Alaska. Fish. Bull. 

100:559-581. 

Munday, D.R., G.L. Ennis, D.G. Wright, D.C. Jeffries, E.R. McGreer, and J.S. Mathers. 

1986. Development and evaluation of a model to predict effects of buried 

underwater blasting charges on fish populations in shallow water areas. Can. 

Tech. Rep. Fish. Aquat. Sci. No. 1418. 49 pp. 

Musick, J.A. and C.J. Limpus. 1997. Habitat utilization and migration in juvenile sea 

turtles. Pp. 137-164. In: P.L. Lutz and J.A. Musick (eds.). The Biology of Sea 

Turtles. Boca Raton: CRC Press. 432 pp. 

Myrberg, A. 1981. Sound communication and interceptions by fishes. Pp. 395-426. In: 

W. Tavolga, R. Fay, and A. Popper (eds.). Hearing and Sound Communication in 

Fishes. New York: Springer-Verlag. 
175 

Myrick, A.C., Jr., E.R. Cassano, and C.W. Oliver. 1990a. Potential for physical injury, 

other than hearing damage, to dolphins from seal bombs used in the yellowfin tuna 

pure-seine fishery: Results from open water tests. U.S. Natl. Mar. Fish. Serv., La 

Jolla, CA. Admin. Rep. LJ-90-07. 28 pp. 

Myrick, A.C., Jr., M. Flink, and C.B. Glick. 1990b. Identification, chemistry and behavior 

of seal bombs used to control dolphins in the yellowfin tuna purse-seine fishery in 

the eastern tropical Pacific. U.S. Natl. Mar. Fish. Serv., La Jolla, CA. Admin. Rep. 

LJ-90-08. 25 pp. 

Nachtigall, P.E., W.W.L. Au, J.L. Pawloski, and P.W.B. Moore. 1995. Risso’s dolphin 

(Grampus griseus) hearing thresholds in Kaneohe Bay, Hawaii. In: R.A. 

Kastelein, J.A. Thomas, and P.E. Nachtigall (eds.). Sensory systems of aquatic 

mammals. Woerden, Netherlands: De Spil Publishing. 

Nachtigall, P.E., W.W.L. Au, and J. Pawloski. 1996. Low-frequency hearing in three 

species of odontocetes. J. Acoust. Soc. Am. 100(4, Pt. 2):2,611. 

Nachtigall, P.E., A. Supin, J.L. Pawloski, and W.W.L. Au. 2001. Measuring recovery 

from temporary threshold shifts with evoked auditory potentials of the bottlenose 

dolphin (Tursiops truncatus). J. Acoust. Soc. Am. 110(5, Pt. 2):2,721. 

Nachtigall, P.E., J.L. Pawloski, and W.L. Au. 2003. Temporary threshold shift and 

recovery following noise exposure in the Atlantic bottlenose dolphin (Tursiops 

truncatus). J. Acoust. Soc. Am. 113(6):3,425-3,429. 

National Institute for Occupational Safety and Health. 1998. Criteria for a recommended 

standard. U.S. Dept. of Health and Human Services, Centers for Disease Control 

and Prevention, National Institute for Occupational Safety and Health, Cincinnati, 

OH. 105 pp. 

National Marine Fisheries Service. 1988. Biological Opinion – Consultation for 

Removal of Certain Outer Continental Shelf Oil and Gas Structures in the Gulf of 

Mexico. U.S. Natl. Mar. Fish. Serv., Silver Springs, MD. 25 July 1988. 

National Marine Fisheries Service. 1995a. Small takes of marine mammals incidental to 

specified activities; offshore seismic activities in southern California. Fed. Regist. 

60:53,753-53,760. 

National Marine Fisheries Service. 1995b. Incidental take of marine mammals; bottlenose 

dolphins and spotted dolphins/Final Rule. Fed. Regist. 60:53,139-53,147. 

National Marine Fisheries Service. 1999. Record of decision for shock testing the 

SEAWOLF submarine. Fed. Regist. 64(13):3,280-3,286. 

National Marine Fisheries Service. 2000. Small takes of marine mammals incidental to 

specified activities; marine seismic-reflection data collection in southern California. 

Notice of receipt of application. 28 March 2000. Fed. Regist. 

65(60):16,374-16,379. 

National Marine Fisheries Service. 2001. Taking and importing marine mammals: Taking 

of marine mammals incidental to naval activities: Final rule (Shipshock trial U.S.S. 

WINSTON S. CHURCHILL DDG 81). Fed. Regist. 66(87):22,450-22,467. 

National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1991. Recovery 

plan for U.S. population of loggerhead turtle. U.S. Natl. Mar. Fish. Serv., 

Washington, DC. 64 pp. 
176 

National Oceanic and Atmospheric Administration. 2002. Report on the workshop on 

acoustic resonance as a source of tissue trauma in cetaceans, 24 and 25 April 2002, 

Silver Spring, MD. U.S. Dept. of Commerce, National Oceanic and Atmospheric 

Administration, U.S. Natl. Mar. Fish. Serv. 

National Research Council. 1996. An assessment of techniques for removing offshore 

structures. Committee on Techniques for Removing Fixed Offshore Structures, 

Marine Board, Commission on Engineering and Technical Systems, National 

Research Council. Washington DC: National Academy Press. 76 pp. 

Nedwell, J., K. Needham, A. Turnpenny, and D. Thompson. 1999. Measurement of 

sound during a 3D seismic survey in Blocks 14/14a of the North Sea. Report by 

Subacoustech Ltd., Hants, U.K. for Texaco Britain PLC, London. Subacoustech 

Ltd. Report Reference 356R0108, February 1999. 54 pp. 

Nedwell, J., K. Needham, J. Gordon, C. Rogers, and T. Gordon. 2001. The effects of 

underwater blast during wellhead severance in the North Sea. Subacoustech Ltd. 

Report No. 469-R-0202, November 2001. 

Nedwell, J., K. Needham, J. Gordon, C. Rogers, and T. Gordon. 2002. The effects of 

underwater blast during wellhead severance in the North Sea. Report by 

Subacoustech, Hampshire, U.K. and Ecologic, Fife, U.K. for Coflex Stena Offshore 

Ltd., BP Exploration Oil Co Ltd., Talisman Ltd., Enterprise Oil Ltd., and Marathon 

Oil UK Ltd., www.subacoustech.com. var. pp. 

Nix, P. and P. Chapman. 1985. Monitoring of underwater blasting operations in False 

Creek, B.C. Pp. 194-210. In: C.D. Greene, F.R. Englehardt, and R.J. Paterson 

(eds.). Effects of explosives in the marine environment. Can. Oil & Gas Lands 

Admin., Environ. Prot. Branch, Ottawa, Ont. Tech. Rep. 5. 

North Pacific Fishery Management Council. 2002. Fishery Management Plan for 

groundfish of the Gulf of Alaska. North Pacific Fishery Management Council, 

Anchorage, AK. 

Office of the Surgeon General. 1991. Conventional warfare; ballistic, blast, and burn 

injuries. USA Textbook of Military Medicine; Vol. 5, Pt. 1. 

Officer, C.B. 1958. Introduction to the Theory of Sound Transmission. New York: 

McGraw-Hill. 

O'Keeffe, D.J. and G.A. Young. 1984. Handbook on the environmental effects of 

underwater explosions. Naval Surface Weapons Center, Dahlgren, VA and Silver 

Spring, MD. NSWC TR 83-240. 

Orr, R.T. and R.C. Helm. 1989. Marine mammals of California. California Natural 

History Guides: 29. University of California Press. 

Parrott, R. 1991. Seismic and acoustic systems for marine survey used by the Geological 

Survey of Canada: Background information for environmental screening. Atlantic 

Geoscience Centre, Geological Survey of Canada, Bedford Institute of 

Oceanography, Dartmouth, NS. 25 pp. 

Payne, R.S. 1970. Songs of the humpback whale (Catalogue No ST-620). Capital 

Records, Hollywood, CA. 

Payne, R.S. and S. McVay. 1971. Songs of humpback whales. Science 

173(3997):585-597. 
177 

Perrin, W.F., B. Wursig, and J.G.M. Thewissen. 2002. Encyclopedia of Marine Mammals. 

San Diego, CA: Academic Press. 1,414 pp. 

Pet-Soede, C., H.S.J. Cesar, and J.S. Pet. 1999. An economic analysis of blast fishing on 

Indonesian coral reefs. Environ. Cons. 26(2):83-93. 

Powell, A. 1995. Underwater explosion shock wave due to a buried charge. J. Acoust. 

Soc. Am. 98(5, Pt. 2):2,865-2,866. 

Pritchard, P.C.H. 1997. Evolution, phylogeny, and current status. Pp. 1-28. In: P.L. 

Lutz and J.A. Musick (eds.). The Biology of Sea Turtles. Boca Raton, FL: CRC 

Press. 

Putt, R.E., Jr. 1982. A quantitative study of fish populations associated with a platform 

within Bucaneer oil field, northwestern Gulf of Mexico. M.S. Thesis, Texas 

A&M University, College Station, TX. 

Reidenberg, J.S. and J.T. Laitman. 2003. Appearance of odontocete respiratory tissues 

after exposure to blast parameters. p. 30. In: R. Gisner (ed.). Environmental 

consequences of underwater sound, 12-16 May 2003. Office of Naval Research, 

Life Sciences Research Office, Bethesda, MD. 

Reiter, G.A. 1981. Cold weather response F/V Ryuko Maru No. 2, St. Paul, Pribiloff 

Islands, Alaska. Pp. 227-231. In: Proceedings 1981 Oil Spill Conference. 

American Petroleum Institute, Washington, DC. API Publ. 4334. 

Rice, D.W. 1998. Marine Mammals of the World - Systematics and Distribution. The 

Society for Marine Mammalogy, Special Publication Number 4. 231 pp. 

Richardson, G.E. 1989. Sea turtles and structure removals in the Gulf of Mexico. 

Pp. 145-146. In: S.A. Eckert, K.L. Eckert, and T.H. Richardson (comps.). 

Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and 

Biology, 7-11 February 1989. Jekyll Island, GA. NOAA Tech. Memo. 

NMFS-SEFC-232. 306 pp. 

Richardson, W.J., B. Würsig, and C.R. Greene. 1986. Reactions of bowhead whales, 

Balaena mysticetus, to seismic exploration in the Canadian Beaufort Sea. J. 

Acoust. Soc. Am. 79:1,117-1,128. 

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. 1995. Marine 

Mammals and Noise. San Diego: Academic Press. 576 pp. 

Richardson, W.J., G.W. Miller, and C.R. Greene, Jr. 1999. Displacement of migrating 

bowhead whales by sounds from seismic surveys in shallow waters of the Beaufort 

Sea. J. Acoust. Soc. Am. 106(4, Pt. 2):2,281. 

Richmond, D.R., J.T. Yelverton, and E.R. Fletcher. 1973. Far-field underwater blast 

injuries produced by small charges. Lovelace Foundation, Albuquerque, NM. 

Rep. No. DNA 3081T. 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J.H. Anderson. 1969. Hearing 

in the giant sea turtle, Chelonia mydas. Proc. Natl. Acad. Sci. 64:884-890. 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J. Anderson. 1970. 

Sensitivity of the green sea turtle's ear as shown by its electrical potentials. J. 

Acoust. Soc. Am. 47:67. 
178 

Ridgway, S.H., D.A. Carder, R.R. Smith, T. Kamolnick, C.E. Schlundt, and W.R. 

Elseberry. 1997. Behavioral responses and temporary shift in masked hearing 

threshold of bottlenose dolphins, Tursiops truncatus, to 1-second tones of 141 to 

201 dB re 1 micro-Pa. Naval Command, Control and Ocean Surveillance Center, 

RDT&E Division, San Diego, CA. Tech. Rep. 1751. 16 pp. 

Riedman, M. 1990. The Pinnipeds - Seals, Sea Lions, and Walruses. University of 

California Press. 439 pp. 

Rogers, P.H. 1977. Weak-shock solution for underwater explosive shock waves. J. 

Acoust. Soc. Am. 62(6):1,412-1,419. 

Ronquillo, I.A. 1950. Anatomical evidence in cases of fish killed by explosives. Bull. 

Fish. Soc. Philip. 1:52-56. 

Rosman, I., G.S. Boland, L. Martin, and C. Chandler. 1987. Underwater sightings of sea 

turtles in the northern Gulf of Mexico. U.S. Dept. of the Interior, Minerals 

Management Service. OCS Study MMS 87-0107. 37 pp. 

Ruckdeschel, C., C.R. Shoop, and G.R. Zug. 2000. Sea turtles of the Georgia coast. 

Occasional Publications of the Cumberland Island Museum, Number 1. 100 pp. 

Rugh, D.J., B.A. Mahoney, C.L. Sims, B.K. Smith, and R.C. Hobbs. 2003. Aerial 

surveys of belugas in Cook Inlet, Alaska, June 2003. Report prepared by National 

Marine Mammals Laboratory, Seattle, WA, and U.S. Natl. Mar. Fish. Serv., 

Alaska Regional Office, Anchorage, AK. 17 pp. 

Russell, B.C., F.H. Talbot, G.R.V. Anderson, and B. Goldman. 1978. Collection and 

sampling of reef fishes. Pp. 329-345. In: D.R. Stoddart and R.E. Johannes (eds.). 

Coral Reefs: Research Methods. Monographs on Oceanographic Methodology 5, 

Paris, France: UNESCO. 

Saila, S.B., V.L.J. Kocic, and J.W. McManus. 1993. Modelling the effects of destructive 

fishing practices on tropical coral reefs. Mar. Ecol. Prog. Ser. 94:51-60. 

Sakaguchi, S., O. Fukuhara, S. Umezawa, M. Fujiya, and T. Ogawa. 1976. The 

influence of underwater explosion on fishes. Bull. Nansei. Reg. Fish. Res. Lab. 

9:33-65. 

Schlundt, C.E., J.J. Finneran, D.A. Carder, and S.H. Ridgway. 2000. Temporary shift in 

masked hearing thresholds of bottlenose dolphins, Tursiops truncatus, and white 

whales, Delphinapterus leucas after exposure to intense tones. J. Acoust. Soc. Am. 

107(6):3,496-3,508. 

Settle, L.R., J.J. Govoni, M.D. Greene, and M.A. West. 2002. Investigation of impacts 

of underwater explosions on larval and early juvenile fishes. Part 1: The effects 

of underwater explosions on larval fish with implications for the Wilmington 

Harbor Project. Report to U.S. Army Corps of Engineers, Wilmington District, 

Wilmington, NC. 64 pp. 

Sigurdson, J.E., J.B. Gaspin, and D.A. Helwig. 2001. Criteria for marine mammal 

auditory threshold shift: Appendix E, Final environmental impact statement: Shock 

trial of the WINSTON S. CHURCHILL (DDG 81). Space and Naval Warfare 

Systems Center, San Diego, CA. 35 pp. 

Sonnier, F., J. Teerling, and H.D. Hoese. 1976. Observations on the offshore reef and 

platform fish fauna of Louisiana. Copeia 1:105-111. 
179 

Stanley, D.R. and C.A. Wilson. 1990. A fishery-dependent based study of fish species 

composition and associated catch rates around oil and gas structures off 

Louisiana. Fish. Bull. 88(4):719-730. 

Stanley, D.R. and C.A. Wilson. 1998. Spatial variation in fish density at three petroleum 

platforms as measured with dual-beam hydroacoustics. Gulf of Mexico Science 

16(1):73-82. 

Stanley, D.R. and C.A. Wilson. 2000. Variation in the density and species composition 

of fishes associated with three petroleum platforms using dual beam 

hydroacoustics. Fisheries 47:161-172. 

Stanley, D.R. and C.A. Wilson. 2002. Seasonal and spatial variation in the biomass and 

size frequency distribution of fish associated with oil and gas platforms in the 

northern Gulf of Mexico. Pp. 421-471. In: M. McKay, J. Nides, and D. Vigil 

(eds.). Proceedings: Gulf of Mexico fish and fisheries: Bringing together new and 

recent research, October 2000. U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 

2002-004. 674 pp. 

Stobutzki, I.C. and D.R. Bellwood. 1998. Nocturnal orientation to reefs by late pelagic 

stage coral reef fishes. Coral Reefs 17:103-110. 

Stone, C.J. 2003. The effects of seismic activity on marine mammals in UK waters, 

1998-2000. Aberdeen, UK. JNCC Report No. 323. 78 pp. 

Stoneburner, D.L. 1982. Satellite telemetry of loggerhead sea turtle movement in the 

Georgia Bight. Copeia 2:400-408. 

Sverdrup, A., E. Kjellsby, P.G. Kruger, R. Floysand, F.R. Knudsen, P.S. Enger, G. 

Serck-Hanssen, and K.B. Helle. 1994. Effects of experimental seismic shock on 

vasoactivity of arteries, integrity of the vascular endothelium and on primary 

stress hormones of the Atlantic salmon. Journal of Fish Biology 45:973-995. 

Szymanski, M.D., D.E. Bain, K. Kiehl, S. Pennington, S. Wong, and K.R. Henry. 1999. 

Killer whale (Orcinus orca) hearing: Auditory brainstem response and behavioral 

audiograms. J. Acoust. Soc. Am. 106(2):1,134-1,141. 

Teleki, G.C. and A.J. Chamberlain. 1978. Acute effects of underwater construction 

blasting on fishes in Long Point Bay, Lake Erie. J. Fish. Res. Board Can. 

35:1,191-1,198. 

Tolimieri, N., A. Jeffs, and J. Montgomery. 2000. Ambient sound as a cue for 

navigation by the pelagic larvae of reef fishes. Mar. Ecol. Prog. Ser. 

207:219-224. 

Tonndorf, J. 1972. Bone conduction. Pp. 197-237. In: J.V. Tobias (ed.). Foundations of 

Modern Auditory Theory, Vol. II. New York: Academic Press. 

Tremel, D.P., J.A. Thomas, K.T. Ramirez, G.S. Dye, W.A. Bachman, A.N. Orban, and 

K.K. Grimm. 1998. Underwater hearing sensitivity of a Pacific white-sided 

dolphin, Lagenorhynchus obliquidens. Aquat. Mamm. 24(2):63-69. 

Urick, R.J. 1975. Principles of Underwater Sound. 3rd ed. New York: McGraw-Hill. 

423 pp. 
180 

Verboom, W.C. 2000. Intense sound levels and marine mammals: Impacts on cetaceans. 

TNO-TPD Rep., Delft, The Netherlands. HAG-RPT-000037. 84 pp. 

Ward, W.D. 1970. Temporary threshold shift and damage risk criteria for intermittent 

noise exposures. J. Acoust. Soc. Am. 48(2, Pt. 2):561-574. 

Ward, W.D. 1991. The role of intermittence in PTS. J. Acoust. Soc. Am. 90(1):164-169. 

Ward, W.D. 1997. Effects of high-intensity sound. Pp. 1,497-1,507. In: M.J. Crocker 

(ed.). Encyclopedia of Acoustics. New York: J. Wiley & Sons. 

Ward, W.D., W. Selters, and A. Glorig. 1961. Exploratory studies on temporary threshold 

shift from impulses. J. Acoust. Soc. Am. 33(6):781-793. 

Waring, G.T., J.M. Quintal, and S.L. Swartz (eds.). 2001. U.S. Atlantic and Gulf of 

Mexico Marine Mammal Stock Assessments – 2001. NOAA Tech. Memo. 

NMFS-NE-168. 307 pp. 

Waring, G.T., J.M. Quintal, and C.P. Fairfield (eds.). 2002. Draft U.S. Atlantic and Gulf 

of Mexico Marine Mammal Stock Assessments – 2002. NOAA Tech. Memo. 

NFMS-NE-169. 183 pp. 

Watkins, W.A. 1986. Whale reactions to human activities in Cape Cod waters. Mar. 

Mamm. Sci. 2(4):251-262. 

Wever, E.G. 1978. The Reptile Ear. Its Structure and Function. Princeton, NJ: Princeton 

University Press. 

Wiley, M.L., J.B. Gaspin, and J.F. Goertner. 1981. Effects of underwater explosions on 

fish with a dynamical model to predict fishkill. Ocean Science and Engineering 

6:223-284. 

Williams, D.M. and A.I. Hatcher. 1983. Structure of fish communities on outer slopes of 

inshore, mid-shelf, and outer shelf reefs of the Great Barrier Reef. Mar. Ecol. 

Prog. Ser. 10:239-250. 

Wilson, C.A. and D.L. Nieland. 2001. Age and growth of red snapper from the northern 

Gulf of Mexico off Louisiana. Fish. Bull. 99(4):653-664. 

Witzell, W.N. 1982. Observations of the green sea turtle (Chelonia mydas) in Western 

Samoa. Copeia 1:183-185. 

Wright, D.G. 1982. A discussion paper on the effects of explosives on fish and marine 

mammals in the waters of the Northwest Territories. Can. Tech. Rep. Fish. Aquat. 

Sci. 1052:1-16. 

Wright, D.G. and G.E. Hopky. 1998. Guidelines for the use of explosives in or near 

Canadian fisheries waters. Can. Tech. Rep. Fish. Aquat. Sci. 2107:1-34. 

Wright, R.A. and W.H. Allton. 1971. Sea otter studies in the vicinity of Amchitka Island. 

Bioscience 21:673-677. 

Würsig, B., T.A. Jefferson, and D.J. Schmidly. 2000. The Marine Mammals of the Gulf 

of Mexico. College Station, TX: Texas A&M University Press. 232 pp. 

Wyneken, J. 1997. Sea turtle locomotion: Mechanics, behavior, and energetics. 

Pp. 165-198. In: P.L. Lutz and J.A. Musick (eds.). The Biology of Sea Turtles. 

Boca Raton, FL: CRC Press. 

Wynne, K. 1992. Guide to marine mammals of Alaska. Alaska Sea Grant College 

Program, Fairbanks, AK. 75 pp. 
181 

Yelverton, J.T. 1981. Underwater explosion damage risk criteria for fish, birds, and 

mammals. Paper presented at the 102nd meeting of the Acoustical Society of 

America, Carillon Hotel, 30 November - 4 December 1981 (Abstract J. Acoust. 

Soc. Am. Suppl. 1, Vol. 70, Fall 1981), Miami Beach, FL. 19 pp. 

Yelverton, J.T., D.R. Richmond, E.R. Fletcher, and R.K. Jones. 1973. Safe distances from 

underwater explosions for mammals and birds. Report by Lovelace Foundation for 

Medical Education and Research, Albuquerque, NM for Defense Nuclear Agency, 

Washington, DC. DNA 3114T. 67 pp. 

Yelverton, J.T., D.R. Richmond, W. Hicks, K. Saunders, and E.R. Fletcher. 1975. The 

relationships between fish size and their response to underwater blast. Defense 

Nuclear Agency, Topical Report DNA 3677T. 

Young, G.A. 1991. Concise methods of predicting the effects of underwater explosions on 

marine life. Naval Surface Weapons Center, Silver Spring, MD. NAVSWC-MP91-220. 22 pp. 

Zhou, K. and Z. Xingduan. 1991. Baiji/The Yangtze River Dolphin and Other Endangered 

Animals of China. Washington, DC and Nanjing, China: Stone Wall Press and 

Yilin Press. 129 pp. 
A-1 

BIBLIOGRAPHIC DATABASE 
A-3 

BIBLIOGRAPHIC DATABASE 

Ahroon, W.A., R.P. Hamernik, and S.F. Lei. 1996. The effects of reverberant blast 

waves on the auditory system. J. Acoust. Soc. Am. 100(4, Pt. 1):2,247-2,257. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ PTS/ TIME 

Akamatsu, T., Y. Hatakeyama, and N. Takatsu. 1993. Effects of pulsed sounds on 

escape behavior of false killer whales. Nippon Suisan Gakkaishi 

59(8):1,297-1,303. 

Keywords: AHD/ DETERRENT/ EFFECT/ FALSE-KILLER/ IMPACT/ 

MARINE MAMMALS/ ODONTOCETES/ SONAR/ SOUND/ UNDERWATER/ 

WHALE 

Alaska Department of Fish and Game. 2002a. ADF&G’s Wildlife Notebook Series: 

Beluga Whale. http://www.state.ak.us/adfg/notebook/marine/beluga.htm. 

Keywords: BELUGA/ MARINE MAMMALS/ DISTRIBUTION/ BEHAVIOR/ 

ABUNDANCE/ ALASKA 

Alaska Department of Fish and Game. 2002b. ADF&G’s Wildlife Notebook Series: 

Harbor Seal. http://www.state.ak.us/adfg/notebook/marine/harseal.htm. 

Keywords: SEAL/ MARINE MAMMALS/ ABUNDANCE/ ALASKA 

Alaska Department of Fish and Game. 2002c. ADF&G’s Wildlife Notebook Series: Sea 

Otter. http://www.state.ak.us/adfg/notebook/marine/seaotter.htm. 

Keywords: OTTER/ MARINE MAMMALS/ IMPACTS/ ALASKA 

Alaska Department of Fish and Game. 2002d. ADF&G’s Wildlife Notebook Series: 

Steller’s Sea Lion. http://www.state.ak.us/adfg/notebook/marine/sealion.htm. 

Keywords: SEA LION/ MARINE MAMMALS/ DISTRIBUTION/ ALASKA 

Alcala, A.C. and E.D. Gomez. 1987. Dynamiting coral reefs for fish: A resourcedestructive fishing method. Pp. 51-60. In: B. Salvat (ed.). Human impacts on 

coral reefs: Facts and recommendations. French Polynesia: Antenne Museum 

E.P.H.E. 

Keywords: ENVIRONMENTAL EFFECTS/ FISH-KILL / MARINE FISH/ 

UNDERWATER EXPLOSIVES/ PHILIPPINES 

Al-Hassani, S.T.S. 1988. Platform removal demands complex explosive designs. Oil 

and Gas Journal, 16 May 1988:35-39. 

Keywords: EXPLOSION CHARACTERISTICS/ OFFSHORE STRUCTURES/ 

SHAPED CHARGES/ UNDERWATER EXPLOSIONS/ WELLHEAD 

SEVERANCE 

Alpin, J.A. 1947. The effect of explosives on marine life. Cal. Fish and Game 33:23-30. 

Keywords: FISH-KILL/ MARINE FISH/ MORTALITY CAUSE/ 

SWIMBLADDER FISH/ CALIFORNIA 
A-4 

American Cetacean Society. 2003a. American Cetacean Society Fact Sheet: Gray 

Whale. http://www.acsonline.org/factpack/graywhl.htm. 

Keywords: GRAY/ MARINE MAMMALS/ BEHAVIOR/ DISTRIBUTION 

American Cetacean Society. 2003b. American Cetacean Society Fact Sheet: Right 

Whale. http://69.5.22.59/factpack/RightWhale.htm. 

Keywords: RIGHT/ MARINE MAMMALS/ BEHAVIOR/ DISTRIBUTION 

Andersen, P. and S. Løken. 1968. Lung damage and lethality by underwater 

detonations. Acta Physiologica Scandinavica 72:6-14. 

Keywords: BLASTING/ DAMAGE/ EFFECT/ IMPACT/ MARINE 

MAMMALS/ UNDERWATER 

Andersen, S. 1970. Auditory sensitivity of the harbour porpoise Phocoena phocoena. 

Invest. Cetacea 2:255-259. 

Keywords: PORPOISE/ MARINE MAMMALS/ AUDITORY BEHAVIOR/ 

NOISE/ SOUND/ TTS/ UNDERWATER 

Angliss, R.P. and K.L. Lodge. 2002. Alaska marine mammal stock assessments, 2002. 

U.S. Dept. of Commerce. NOAA Tech. Memo. NMFS-AFSC-133. 224 pp. 

Keywords: MARINE MAMMALS/ STOCK/ ABUNDANCE/ ALASKA 

Arons, A.B. 1954. Underwater explosion shock wave parameters at large distances from 

the charge. J. Acoust. Soc. Am. 26(3):343-346. 

Keywords: UNDERWATER EXPLOSIONS/ DISTANCE SCALING/ SHOCK 

WAVES 

Arons, A.B. and R.H. Cole. 1950. Design and use of piezoelectric gauges for 

measurement of large transient pressures. Review of Scientific Instruments 

21(1):31-38. 

Keywords: PIEZOELECTRIC GAUGES/ PRESSURE MEASUREMENT/ 

SHOCK WAVES 

Au, W.L., P.E. Nachtigall, and J.L. Pawloski. 1999. Temporary threshold shift in 

hearing induced by an octave band of continuous noise in the bottlenose dolphin. 

J. Acoust. Soc. Am. 106(4, Pt. 2):2,251. 

Keywords: BOTTLENOSE/ DOLPHIN/ EFFECT/ IMPACT/ MARINE 

MAMMALS/ NOISE/ TTS/ UNDERWATER/ WHALE 

Baird, I.G., B. Mounsouphom, and P.J. Stacey. 1994. Preliminary surveys of Irrawaddy 

dolphins (Orcella brevirostris) in Lao PDR and northeastern Cambodia. Rep. Int. 

Whal. Comm. 44:367-369. 

Keywords: BLASTING/ DOLPHIN/ IMPACT/ MARINE MAMMALS/ RIVER/ 

UNDERWATER 

Barlow, J. 1994. Abundance of large whales in California coastal waters: A comparison 

of ship surveys in 1979/80 and in 1991. Rep. Int. Whal. Comm. 44:399-406. 

Keywords: MARINE MAMMALS/ CALIFORNIA/ ABUNDANCE/ SURVEY 
A-5 

Barlow, J. 1997. Preliminary estimates of cetacean abundance off California, Oregon, 

and Washington based on a 1996 ship survey and comparisons of passing and 

closing modes. Available from Southwest Fisheries Science Center, P.O. Box 

271, La Jolla, CA. Admin. Rept. LJ-97-11. 25 pp. 

Keywords: MARINE MAMMALS/ CALIFORNIA/ OREGON/ 

WASHINGTON/ ABUNDANCE/ SURVEY 

Bartol, S.M. and D. Ketten. 2003. Auditory brainstem responses of multiple species of 

sea turtles. p. 29. In: R. Gisner (ed.). Environmental Consequences of 

Underwater Sound (ECOUS) Abstracts, 12-16 May 2003, San Antonio, TX. 

Office of Naval Research, Arlington, VA. 86 pp. 

Keywords: PIEZOELECTRIC GAUGES/ PRESSURE MEASUREMENT/ 

SHOCK WAVES 

Bartol, S.M. and J.A. Musick. 2003. Sensory biology of sea turtles. Pp. 79-102. In: 

P.L. Lutz, J.A. Musick, and J. Wyneken (eds.). The Biology of Sea Turtles, 

Volume II. Boca Raton, FL: CRC Press. 

Keywords: MARINE TURTLES/ EAR/ ANATOMY/ AUDITORY 

BRAINSTEM RESPONSES/ AUDITORY BEHAVIOR 

Bartol, S.M., J.A. Musick, and M.L. Lenhardt. 1999. Auditory evoked potentials of the 

loggerhead sea turtle (Caretta caretta). Copeia 3:836-840. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ ACOUSTICS/ AUDITORY BRAINSTEM RESPONSE 

Baxter II, L. 1985. Mortality of fish subjected to explosive shock as applied to oil well 

severance on Georges Bank. Pp. 119-134. In: C.D. Greene, F.R. Englehardt, and 

R.J. Paterson (eds.). Proceedings of the workshop on effects of explosives in the 

marine environment, 29-31 January 1985, Halifax. Can. Oil and Gas Lands 

Admin., Environ. Prot. Br., Ottawa, Ont. Tech. Rep. No. 5. 

Keywords: EXPLOSIVE PLATFORM REMOVAL/ EXPLOSIVES/ 

FISH-KILL/ MARINE FISH/ OFFSHORE STRUCTURE REMOVAL/ 

GEORGES BANK/ ACOUSTICS/ BLASTING 

Baxter II, L., E.E. Hays, G.R. Hampson, and R.H. Backus. 1982. Mortality of fish 

subjected to explosive shock as applied to oil well severance on Georges Bank. 

Woods Hole Oceanographic Institution, Woods Hole, MA. Tech. Rep. 

WHOI-82-54. 69 pp. 

Keywords: ENVIRONMENTAL EFFECTS/ EXPLOSIVE PLATFORM 

REMOVAL/ FISH-KILL/ GEORGES BANK/ MATHEMATICAL MODELS/ 

LETHAL RANGES 

Bayley, P.B. and D.J. Austen. 1988. Comparison of detonating cord and rotenone for 

sampling fish in warmwater impoundments. North American Journal of Fisheries 

Management 8(3):310-316. 

Keywords: FISHES/ SAMPLING/ UNDERWATER EXPLOSIVES 
A-6 

Bekesy, G. 1948. Vibration of the head in a sound field, and its role in hearing by bone 

conduction. J. Acoust. Soc. Am. 20:749-760. 

Keywords: ACOUSTICS/ BONE CONDUCTED HEARING 

Bibee, D.L. and S. Theophanis. 2001. Acoustic monitoring of DET tests San Clemente 

Island, California-October 2000. Seafloor Sciences, Naval Research Laboratory, 

Stennis Space Center, MS. 37 pp. 

Keywords: BLASTING/ EFFECT/ FISH/ IMPACT/ MARINE MAMMALS/ 

MONITORING/ NAVY/ PHYSICAL/ UNDERWATER 

Blackburn, J.E., K. Anderson, C.I. Hamilton, and S.J. Staff. 1979. Pelagic and demersal 

fish assessment in the lower Cook Inlet estuary system. Final report from Alaska 

Department of Fish and Game to NOAA/ OSCEAP. 330 pp. 

Keywords: MARINE FISH/ ALASKA 

Blaik, M. and E.A. Christian. 1965. Near-surface measurements of deep explosions. I. 

Pressure pulses from small charges. J. Acoust. Soc. Am. 38:50-56. 

Keywords: BUBBLE PULSE/ PRESSURE MEASUREMENT/ SHOCK 

WAVES/ UNDERWATER EXPLOSIONS 

Bohne, B.A., J.A. Thomas, E.R. Yohe, and S.H. Stone. 1985. Examination of potential 

hearing damage in Weddell seals (Leptonychotes weddelli) in McMurdo Sound, 

Antarctica. Antarct. J. U.S. 20:174-176. 

Keywords: BLASTING/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS/ PINNIPED/ SEAL/ WEDDELL 

Bohne, B.A., D.G. Bozzay, and J.A. Thomas. 1986. Evaluation of inner ear pathology in 

Weddell seals. Antarct. J. U.S. 21:208. 

Keywords: BLASTING/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS/ PINNIPED/ SEAL/ WEDDELL 

Boland, G.S. 2002. Fish and epifaunal community observations at an artificial reef near 

a natural coral reef: Nineteen years at Platform High Island A389-A, from bare 

steel to coral habitat. Pp. 372-392. In: M. McKay, J. Nides, and D. Vigil (eds.). 

Proceedings: Gulf of Mexico fish and fisheries: Bringing together new and recent 

research, October 2000. U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 

2002-004. 674 pp. 

Keywords: MARINE FISH/ OFFSHORE STRUCTURES/ GULF OF MEXICO 

Booth, J. and K.A. Peters. 1972. Behavioural studies on the green turtle (Chelonia 

mydas) in the sea. Anim. Behav. 20:808-812. 

Keywords: MARINE TURTLES/ GREEN TURTLE/ CHELONIA MYDAS/ 

BEHAVIOR 
A-7 

Bowles, A.E., M. Smultea, B. Würsig, D.P. DeMaster, and D. Palka. 1994. Relative 

abundance and behavior of marine mammals exposed to transmissions for the 

Heard Island feasibility test. J. Acoust. Soc. Am. 96(4):2,469-2,484. 

Keywords: ACOUSTICS/ BLUE/ DOLPHIN/ EFFECT/ ELEPHANT FIN FUR/ 

FUR-SEAL/ IMPACT/ LOW-FREQUENCY/ MARINE MAMMALS/ MINKE/ 

NOISE/ PILOT/ SEAL/ SEI/ SEISMIC/ SPERM/ UNDERWATER/ WHALE 

Box, P., F. Marian, and D. Wiese. 2000. Shoalwater Bay defense training area dugong 

research program underwater blast measurements. Australia Department of 

Defense, Defense Science and Technology Organization, Melbourne, Australia. 

DSTO-TR-1024. 54 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ 

PHYSICAL/ SHALLOW/ UNDERWATER 

Brekhovskikh, L.M. 1980. Waves in Layered Media. 2nd ed. New York: Academic 

Press. 59 pp. 

Keywords: ACOUSTIC WAVES/ LAYERED MEDIA 

Brown, F.A. 1939. Responses of the swimbladder of the guppy, Lebistes reticulates, to 

sudden pressure decreases. Biological Bulletin 76:48-58. 

Keywords: LARVAL FISH/ SWIMBLADDER/ PRESSURE EFFECTS 

Carder, D.A. and S.H. Ridgway. 1990. Auditory brainstem response in a neonatal sperm 

whale, Physeter spp. J. Acoust. Soc. Am. 88(Suppl. 1):S4. 

Keywords: HEARING/ NOISE/ SPERM/ MARINE MAMMALS/ AUDITORY 

BRAINSTEM RESPONSE 

Carr, A. 1996. A Naturalist in Florida: A Celebration of Eden. New Haven: Yale 

University Press. 

Keywords: NATURAL HISTORY/ FLORIDA/ CONSERVATION/ 

ENVIRONMENTAL ASSESSMENT 

Carr, A.F. 1954. The passing of the fleet. Am. Inst. Biol. Sci. Bull. 4(5):17-19. 

Keywords: MARINE TURTLES/ CONSERVATION 

Carretta, J.V., M.M. Muto, J. Barlow, J. Baker, K.A. Forney, and M. Lowry. 2002. U.S. 

Pacific marine mammal stock assessments: 2002. NOAA Tech. Memo. NMFS, 

NOAA-TM-SWFSC-346. 

Keywords: MARINE MAMMALS/ STOCK/ ABUNDANCE/ PACIFIC 

Cassano, E.R., A.C. Myrick Jr., C.B. Glick, R.C. Holland, and C.E. Lennert. 1990. The 

use of seal bombs in the yellowfin tuna purse-seine fishery. U.S. Natl. Mar. Fish. 

Serv., La Jolla, CA. Admin. Rep. LJ-90-09. 31 pp. 

Keywords: BLASTING/ DETERRENT/ DOLPHIN/ FISHERY/ 

INTERACTION/ MARINE MAMMALS / PHYSICAL/ UNDERWATER 
A-8 

Cavanagh, R.C. 2000. Criteria and thresholds for adverse effects of underwater noise on 

marine animals. Report by Science Applications International Corp., McLean, 

VA for U.S. Air Force, Air Force Research Laboratory, Wright-Patterson AFB, 

Ohio. Contract F41624-96-C-9005. 

Keywords: BLASTING/ EFFECT/ FISH/ IMPACT/ MARINE MAMMALS/ 

MILITARY/ NOISE/ PHYSICAL/ SEA/ SHIPPING/ SONAR/ TORPEDO/ 

TURTLE/ UNDERWATER 

Christian, E.A. 1973. The effects of underwater explosions on swimbladder fish. Naval 

Ordnance Laboratory, White Oak, Silver Spring, MD. NOLTR 73-103. 33 pp. 

Keywords: FISHES/ EXPLOSION EFFECTS/ EFFECTS/ SWIMBLADDER 

FISH/ MATHEMATICAL MODELS/ LETHAL RANGES/ SHOCK WAVES 

Clark, J.A., J.A. Young, and J.B. Gaspin. 1999. Validation of a system for synthesizing 

distant signatures of underwater explosions for sea mammal hearing studies. J. 

Acoust. Soc. Am. 105(2, Pt. 2):1,048. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ MODEL/ 

PHYSICAL 

CNO. 1999. Appendix B: Background on criteria and thresholds for injury and 

harassment of marine life by underwater sound from Navy projectors and 

explosives (for single events). U.S. Navy, OPNAV N45 Marine Mammal 

Program, Washington, DC. 44 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

SOUND/ UNDERWATER/ WHALE 

Cole, R.H. 1948. Underwater explosions. Princeton, NJ: Princeton University Press. 

437 pp. 

Keywords: DETONATION/ EXPLOSION PHYSICS/ EXPLOSION 

CHARACTERISTICS/ SHOCK WAVES/ UNDERWATER EXPLOSIONS/ 

UNDERWATER ACOUSTICS 

Notes: LC Control Number: 65022737, Bibliography: p. 427-432 

Connor, J.G., Jr. 1990. Underwater blast effects from explosive severence of offshore 

platform legs and well conductors. Naval Surface Warfare Center, Silver Spring, 

MD. NAVSWC-TR-90-532. 146 pp. 

Keywords: GULF OF MEXICO/ UNDERWATER EXPLOSIONS/ 

ENVIRONMENTAL EFFECTS/ EXPLOSIVE STRUCTURE REMOVALS 

Continental Shelf Associates, Inc. 1982. Study of the effect of oil and gas activities on 

reef fish populations in the Gulf of Mexico OCS area. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

OCS Report MMS 82-10. 

Keywords: OIL AND GAS INDUSTRY/ GULF OF MEXICO/ MARINE FISH/ 

POPULATION EFFECTS 
A-9 

Continental Shelf Associates, Inc. 2002. Geological and geophysical exploration for 

minerals resources on the Gulf of Mexico outer continental shelf: Draft 

programmatic environmental assessment. Prepared for the U.S. Dept. of the 

Interior, Minerals Management Service, Gulf of Mexico OCS Region, New 

Orleans, LA. 

Keywords: ENVIRONMENTAL ASSESSMENT/ GULF OF MEXICO/ 

EXPLORATION/ MINERALS MANAGEMENT SERVICE 

Craig, J. 2000. Personal Communication, 19 January 2000. Naval Surface Warfare 

Canter, Carderock Division, Bethesda, MD. 

Keywords: BLASTING/ EFFECT / IMPACT/ MARINE MAMMALS 

Craig, J.C. 1999. Personal Communication, 15 April 1999. Naval Surface Warfare 

Center, Carderock Division, Bethesda, MD. 

Keywords: BLASTING/ IMPACT / MARINE MAMMALS 

Craig, J.C. and C.W. Hearn. 1998. Physical impacts of explosions on marine mammals 

and turtles. Appendix D, Final environmental impact statement: Shock testing the 

SEAWOLF submarine. Naval Surface Warfare Center, Carderock Division, 

Bethesda, MD. 42 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

SOUND/ TURTLE/ UNDERWATER 

Craig, J.C., Jr. 1999. Physical impacts of explosions on marine mammals and turtles. 

Appendix D, Draft environmental impact statement: Shock trial of the WINSTON 

S. CHURCHILL (DDG 81). Naval Surface Warfare Center, Carderock Division, 

Bethesda, MD. 43 pp. 

Keywords: BALEEN/ BLASTING/ EFFECT/ EIS/ IMPACT/ MAMMAL/ 

MARINE MAMMALS/ NAVY/ ODONTOCETES/ UNDERWATER/ WHALE 

Craig, J.C., Jr. 2001. Physical impacts of explosions on marine mammals and turtles. 

Appendix D, Final environmental impact statement: Shock trial of the WINSTON 

S. CHURCHILL (DDG 81). Naval Surface Warfare Center, Carderock Division, 

Bethesda, MD. 43 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

SOUND/ TURTLE/ UNDERWATER 

Cummings, W.C., J.M. Holzmann, and P.O. Thompson. 1975. Underwater sound 

pressure minima in bioacoustic test tanks. NUC TP 450. U.S. Naval Undersea 

Cent., San Diego, CA. NTIS AD-A032768. 40 pp. 

Keywords: MARINE MAMMALS/ HEARING 

Dailey, M.D., D.J. Reish, and J.W. Anderson (eds.). 1993. Ecology of the Southern 

California Bight - A Synthesis and Interpretation. Berkeley, CA: University of 

California Press. 926 pp. 

Keywords: MARINE MAMMALS/ ECOLOGY/ SOUTHERN CALIFORNIA 

BIGHT 
A-10 

Davis, R.W., W.E. Evans, and B. Würsig (eds.). 2000. Cetaceans, sea turtles and 

seabirds in the northern Gulf of Mexico: Distribution, abundance and habitat 

associations, Vol. II: Technical report. U.S. Dept. of the Interior, Geological 

Survey, Biological Resource Division, USGS/ BRD/ CR-1999-0006, and 

Minerals Management Service, New Orleans, LA. OCS Study MMS 2000-003. 

Keywords: DISTRIBUTION/ MARINE MAMMALS/ MARINE TURTLES/ 

BIRDS/ GULF OF MEXICO/ ABUNDANCE/ HABITAT UTILIZATION 

Demarchi, M.W., W.B. Griffiths, D. Hannay, R. Racca, and S. Carr. 1998. Effects of 

military demolitions and ordnance disposal on selected marine life in marine 

training and exercise area WQ. Report by LGL Limited, Environmental Research 

Associates, Sidney, BC and Jasco Research Ltd., Sidney, BC. For the Department 

of National Defense, CFB Esquimalt, Esquimalt, BC. 

Keywords: ACOUSTICS/ BLASTING/ EFFECT/ FISH/ IMPACT/ MARINE 

MAMMALS/ MILITARY/ NOISE/ SEAL/ UNDERWATER 

DEMEX. 2002. Explosive technology report for structure removals in the Gulf of 

Mexico. Draft. DEMEX, Division of TEi Construction Services, Inc. 

Keywords: EXPLOSIVE CHARGE DESIGN/ TYPES OF EXPLOSIVES/ 

EXPLOSIVE USES/ SHAPE CHARGE/ BULK CHARGES/ FOCUSING 

CHARGES/ FLEXIBLE LINEAR CHARGES 

Department of the Navy. 1998. Final environmental impact statement: Shock testing the 

SEAWOLF submarine. Department of the Navy, Southern Division, Naval 

Facilities Engineering Command, North Charleston, SC. var. pp. 

Keywords: ENVIRONMENTAL IMPACT/ BLASTING/ SEISMIC/ 

UNDERWATER EXPLOSIONS/ EXPLOSION EFFECTS 

Department of the Navy. 2001. Shock Trial of the WINSTON S. CHURCHILL 

(DDG 81), Final Environmental Impact Statement, February 2001. Prepared by 

Continental Shelf Associates, Inc. 

Keywords: UNDERWATER EXPLOSIONS/ MARINE TURTLES/ 

ENVIRONMENTAL EFFECTS/ ATLANTIC OCEAN 

Department of the Navy. 2002. Final Environmental Impact Statement/ Overseas 

Environmental Impact Statement - Point Mugu Sea Range. March 2002. Naval 

Air Warfare Center Weapons Division, Pt. Mugu, CA. 

Keywords: ENVIRONMENTAL IMPACT/ MARINE MAMMALS/ MUGU 

Dick, R.A., D.V. D’Andrea, and L.R. Fletcher. 1993. Back to basics: Properties of 

explosives. Journal of Explosive Engineering 10(6):28-45. 

Keywords: DETONATION/ EXPLOSION CHARACTERISTICS/ CHARGE 

SIZE 
A-11 

Dodd, C.K., Jr. 1988. Synopsis of the biological data on the loggerhead sea turtle 

Caretta caretta (Linnaeus, 1758). U.S. Fish Wildl. Serv. Biol. 8814. 110 pp. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ NATURAL HISTORY 

Dzhumaliyev, M.K. 1977. The morphology and trophic characteristics of the swim 

bladder in some orders of fish. Journal of Ichthyology 17(2):284-292. 

Keywords: ANATOMY/ PHYLOGENY/ SWIMBLADDER/ SWIMBLADDER 

FISH 

Edwards, R.E., K.J. Sulak, and D. Weaver. 2002. Deepwater petroleum structures as 

fish aggregating devices: An in-progress project report. Pp. 50-64. In: M. 

McKay, J. Nides, and D. Vigil (eds.). Proceedings: Gulf of Mexico fish and 

fisheries: Bringing together new and recent research, October 2000. U.S. Dept. of 

the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New 

Orleans, LA. OCS Study MMS 2002-004. 674 pp. 

Keywords: MARINE FISH/ OFFSHORE STRUCTURES/ FISHERY 

Egloff, M. 1996. Failure of swim bladder inflation of perch, Perca fluvitilis L., found in 

natural populations. Aquatic Sciences 58(1):17-23. 

Keywords: FISHES/ SWIMBLADDER FISH/ LARVAL FISH/ EFFECTS 

Enger, P.S. 1981. Frequency discrimination in teleosts central or peripheral? Pp. 

243-255. In: W.N. Tavolga, A.N. Popper, and R.R. Fay (eds.). Hearing and 

Sound Communication in Fishes. New York: Springer Verlag. 

Keywords: ACOUSTICS/ ACOUSTIC BEHAVIOR/ AUDITORY BEHAVIOR/ 

SOUND WAVES/ FISHES 

Ernst, C.H., J.E. Lovich, and R.W. Barbour. 1994. Turtles of the United States and 

Canada. Washington, DC: Smithsonian Institute Press. 578 pp. 

Keywords: MARINE TURTLES/ NATURAL HISTORY 

Ferguson, R.G. 1962. The effects of underwater explosions on yellow perch. Can. Fish. 

Cult. 29:31-39. 

Keywords: ENVIRONMENTAL EFFECTS/ FISH-KILL/ FISHES/ 

SWIMBLADDER FISH 

Filadelfo, R.J. and J.D. Mintz. 2001. Impact of marine mammal protection requirements 

on Navy operations. Center for Naval Analysis Report, Alexandria, VA. CRM 

D0002866.A3. 33 pp. 

Keywords: BLASTING/ GUIDELINE/ LAW/ MARINE MAMMALS/ 

MITIGATION/ MONITORING/ NAVY/ SONAR/ SONOBUOY/ 

UNDERWATER 

Finkelstein, R. 1947. The normal reflection of shock waves. Physical Review 

71(1):42-48. 

Keywords: EXPLOSION PHYSICS/ SHOCK WAVES 
A-12 

Finneran, J.J. 2003. A TTS-based damage risk model for marine mammals. p. 77. In: 

R. Gisner (ed.). Environmental consequences of underwater sound, 

12-16 May, 2003. Office of Naval Research, Life Sciences Research Office, 

Bethesda, MD. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

TTS/ UNDERWATER 

Finneran, J.J., C.E. Schulundt, D.A. Carder, J.A. Clark, J.A. Young, J.B. Gaspin, and 

S.H. Ridgway. 2000. Auditory and behavioral responses of bottlenose dolphins 

(Tursiops truncatus) and a beluga whale (Delphinapterus leucas) to impulsive 

sounds resembling distant signatures of underwater explosions. J. Acoust. Soc. 

Am. 108(1): 417-431. 

Keywords: BLASTING/ DOLPHIN/ EFFECT/ IMPACT/ MARINE 

MAMMALS/ NOISE/ SOUND/ TTS/ UNDERWATER 

Finneran, J.J., C.E. Schlundt, R. Dear, D.A. Carder, and S.H. Ridgway. 2002. 

Temporary shift in masked hearing thresholds in odontocetes after exposure to 

single underwater impulses from a seismic watergun. J. Acoust. Soc. Am. 

111(6):2,929-2,940. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ NAVY/ 

ODONTOCETES/ SEISMIC/ SONAR/ WHALE 

Fish, J.F. and J.S. Vania. 1971. Killer whale, Orcinus orca, sounds repel white whales, 

Delphinapterus leucas. Fish. Bull. 69(3):531-535. 

Keywords: BLASTING/ EFFECT/ IMPACT/ KILLER/ MARINE MAMMALS/ 

SOUND/ WHALE/ WHITE 

Fitch, J.E. and P.H. Young. 1948. Use and effect of explosives in California coastal 

waters. Cal. Fish and Game 34:53-70. 

Keywords: ACOUSTICS/ BLASTING/ EFFECT/ FISH/ IMPACT/ LIB/ 

MUGU/ SOUND/ UNDERWATER 

Fleming, E.H. 2001. Swimming against the tide: Recent surveys of exploitation, trade, 

and management of marine turtles in the northern Caribbean. TRAFFIC North 

America. 161 pp. 

Keywords: MARINE TURTLES/ TRADE/ EXPLOITATION 

Frost, K.J., L.F. Lowrey, and R.R. Nelson. 1984. Belukha whale studies in Bristol Bay 

Alaska. Pp. 187-200. In: B.R. Melteff and D.H. Rosenberg (eds.). Proceedings: 

Workshop on biological interactions among marine mammals and commercial 

fisheries in the southeastern Bering Sea, Oct. 1983, Anchorage, AK. Univ. of 

Alaska, Fairbanks, AK. Univ. of Alaska Sea Grant Rep. 84-1. 

Keywords: ALASKA/ BLASTING/ IMPACT/ MARINE MAMMALS/ NOISE/ 

UNDERWATER/ WHALE/ WHITE 
A-13 

Fry Jr., D.H. and K.W. Cox. 1953. Observations on the effects of black powder 

explosions on fish life. Cal. Fish and Game 39(2):233-236. 

Keywords: MARINE FISH/ ROCKFISH/ UNDERWATER EXPLOSIONS/ 

CALIFORNIA 

Fuller, D.A. and A.M. Tappan. 1986. The occurrence of sea turtles in Louisiana coastal 

waters. Center for Wetland Resources, Louisiana State University, Baton Rouge, 

LA. Unpublished report, LSU-CFI-86-28. 

Keywords: MARINE TURTLES/ LOUISIANA/ DISTRIBUTION 

Fuller, R.G. and J.B. Kirkwood. 1977. Ecological consequences of nuclear testing. 

p. 682. In: M.L. Merrit and R.G. Fuller (eds.). The environment of Amchitka 

Island, Alaska. Energy Res. & Devel. Admin., Springfield, VA. 

NTIS TID-26712. 

Keywords: ALASKA/ BLASTING/ MARINE MAMMALS/ UNDERWATER 

Gallaway, B.J. and G.S. Lewbel. 1982. The ecology of petroleum platforms in the 

northwestern Gulf of Mexico: A community profile. U.S. Dept. of the Interior, 

Fish and Wildlife Service, Office of Biological Services. FWS/OBS-82/27. 

92 pp. 

Keywords: GULF OF MEXICO/ MARINE FISH/ MARINE ORGANISMS/ 

OFFSHORE STRUCTURES/ OIL AND GAS INDUSTRY/ PRODUCTION 

PLATFORMS 

Gaspin, J.B. 1975. Experimental investigations on swimbladder fish. I: Chesapeake Bay 

tests. Naval Surface Weapons Center, Silver Spring, MD. Final Report 

NSWC/WOL.TR 75-58. 

Keywords: EXPLOSION EFFECTS/ FISH-KILL/ FISHES/ LETHAL 

RANGES/ SHOCK WAVE EFFECTS / SWIMBLADDER FISH/ 

UNDERWATER EXPLOSIONS/ CHESAPEAKE BAY/ CAGING 

EXPERIMENTS 

Gaspin, J.B. 1983. Safe swimmer ranges from bottom explosions. Naval Surface 

Weapons Center, White Oak Lab, Def. Tech. Info. Cent., Silver Spring, MD. 

NSWC/WOL.TR-83-84. 

Keywords: HUMAN INJURY/ SAFE RANGES/ UNDERWATER 

EXPLOSIONS/ UNDERWATER EXPLOSIONS/ EFFECTS 

Notes: Additional ID: AD-B086375 

Gaspin, J.B., M.L. Wiley, and C.B. Peters. 1976. Experimental investigations on 

swimbladder fish. II: 1975 Chesapeake Bay tests. Naval Surface Weapons 

Center, Silver Spring, MD. Final Report NSWC/ WOL.TR 76-61. 

Keywords: EXPLOSION EFFECTS/ FISH-KILL/ FISHES/ LETHAL 

RANGES/ SHOCK WAVE EFFECTS / SWIMBLADDER FISH/ 

UNDERWATER EXPLOSIONS/ CHESAPEAKE BAY/ CAGING 

EXPERIMENTS 
A-14 

Geers, T.L. and K.S. Hunter. 2002. An integrated wave-effects model for an underwater 

explosion bubble. J. Acoust. Soc. Am. 111(4):1,584-1,601. 

Keywords: BUBBLES/ UNDERWATER SOUND/ NONLINEAR 

ACOUSTICS/ SHOCK WAVE EFFECTS/ BUBBLE PULSE/ SHOCK WAVES/ 

UNDERWATER EXPLOSIONS/ UNDERWATER ACOUSTICS 

Gentry, R.L., E.C. Gentry, and J.F. Gilman. 1990. Responses of northern fur seals to 

quarrying operations. Mar. Mamm. Sci. 6(2):151-155. 

Keywords: AIR/ BLASTING/ EFFECT/ FUR/ IMPACT/ MARINE 

MAMMALS/ NOISE/ PINNIPED/ SEAL/ SOUND 

Geraci, J.R. and D.J. St. Aubin. 1985. Effects of offshore oil and gas development on 

marine mammals and turtles. Pp. 12-1 to 12-34. In: D.F. Boesch and N.N. 

Rabalais (eds.). The Long-term Effects of Offshore Oil and Gas Development: 

An Assessment and a Research Strategy. A Final Report to the National Marine 

Pollution Office, National Oceanic and Atmospheric Administration, Rockville, 

MD. 

Keywords: MARINE TURTLES/ ENVIRONMENTAL EFFECTS/ OFFSHORE 

OIL AND GAS 

Gisner, R.C. (ed.). 1998. Workshop on the effects of anthopogenic noise in the marine 

environment, 10-12 February 1998. Marine Mammal Science Program, Office of 

Naval Research, Arlington, VA. 141 pp. 

Keywords: BEHAVIOR/ BLASTING/ EFFECT/ HUMAN-DIVER/ IMPACT/ 

MARINE MAMMALS/ MITIGATION/ MONITORING/ NOISE/ SEAL/ 

SONAR/ TTS/ UNDERWATER/ WHALE 

Gitschlag, G.R. 1990. Sea turtle monitoring at offshore oil and gas platforms. In: T.H. 

Richardson, J.I. Richardson, and M. Donnelly (comps.). Proceedings of the Tenth 

Annual Workshop on Sea Turtle Biology and Conservation, 20-24 February 1990, 

Hilton Head, South Carolina. NOAA Tech. Memo. NMFS-SEFSC-278. 223 pp. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ EXPLOSIVE 

PLATFORM REMOVALS/ SURVEYS/ NATIONAL MARINE FISHERIES 

SERVICE 

Gitschlag, G.R. and B.A. Herczeg. 1994. Sea turtle observations at explosive removals 

of energy structures. Mar. Fish. Rev. 56(2):1-8. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ EXPLOSIVE 

PLATFORM REMOVALS/ OIL AND GAS INDUSTRY/ PRODUCTION 

PLATFORMS/ ASW/ USA / LOUISIANA/ TEXAS/ UNDERWATER 

EXPLOSIONS/ OFFSHORE STRUCTURES 
A-15 

Gitschlag, G.R. and M. Renaud. 1989. Sea turtles and the explosive removal of offshore 

oil and gas structures. Pp. 67-68. In: S.A. Eckert, K.L. Eckert, and 

T.H. Richardson (comps.). Proceedings of the Ninth Annual Workshop on Sea 

Turtle Conservation and Biology. NOAA Tech. Memo. NMFS-SEFSC-232. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ EXPLOSIVE 

PLATFORM REMOVALS/ ENVIRONMENTAL EFFECTS/ SURVEYS/ 

NATIONAL MARINE FISHERIES SERVICE 

Gitschlag, G.R., B.A. Herczeg, and T.R. Barcak. 1997. Observations of sea turtles and 

other marine life at the explosive removal of offshore oil and gas structures in the 

Gulf of Mexico. Gulf Res. Rep. 9(4):247-262. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ EXPLOSIVE 

PLATFORM REMOVALS/ NATIONAL MARINE FISHERIES SERVICE/ 

SURVEYS/ ENVIRONMENTAL EFFECTS/ FISH-KILL 

Gitschlag, G.R., M.J. Schirripa, and J.E. Powers. 2000. Estimation of fisheries impacts 

due to underwater explosives used to sever and salvage oil and gas platforms in 

the U.S. Gulf of Mexico: Final report. U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS 

Study MMS 2000-087. 80 pp. 

Keywords: ENVIRONMENTAL ASSESSMENT/ EXPLOSIVE PLATFORM 

REMOVAL/ FISH-KILL/ FISHERY MANAGEMENT/ GULF OF MEXICO/ 

MARINE FISH/ NATIONAL MARINE FISHERIES SERVICE/ OFFSHORE 

STRUCTURE REMOVAL/ OIL AND GAS INDUSTRY/ SWIMBLADDER 

FISH/ POPULATION EFFECTS/ RED SNAPPER 

Glass, K. 1989. Are dolphins being deafened in the Pacific? Oceanus 32(4):83-85. 

Keywords: DOLPHINS/ MARINE MAMMALS/ HEARING/ ACOUSTICS/ 

NOISE/ EFFECTS/ PACIFIC 

Goertner, J.F. 1981. Fish-kill ranges for oil well severance explosions. Naval Surface 

Weapons Center, Silver Spring, MD. NSWC TR 81-149. 

Keywords: FISH-KILL / SWIMBLADDER FISH/ UNDERWATER 

EXPLOSIONS/ OIL WELL SEVERANCE/ WELLHEAD REMOVAL/ SHOCK 

WAVES/ DISTANCE SCALING/ FISH MORTALITY/ PRESSURE 

MEASUREMENT/ SHOCK WAVES/ SWIMBLADDER/ UNDERWATER 

EXPLOSIONS/ WELLHEAD SEVERANCE 

Goertner, J.F. 1982. Prediction of underwater explosion safe ranges for sea mammals. 

Naval Surface Weapons Center, Silver Spring, MD. NSWC/WOL TR 82-188. 

NTIS ADA 139823. 25 pp. 

Keywords: UNDERWATER EXPLOSIONS/ MARINE MAMMALS/ 

BLASTING 
A-16 

Goertner, J.F., M.L. Wiley, G.A. Young, and W.W. McDonald. 1994. Effects of 

underwater explosions on fish without swimbladders. Naval Surface Warfare 

Center, Dahlgren Division, White Oak Detachment, Silver Spring, MD. 

NSWC TR 88-114. 

Keywords: ACOUSTICS/ EXPLOSIONS/ FISH 

Goold, J.C. 1996. Acoustic assessment of populations of common dolphin Delphinus 

delphis in conjunction with seismic surveying. J. Mar. Biol. Assoc. U.K 

76:811-820. 

Keywords: SEISMIC/ SURVEY/ DOLPHIN/ MARINE MAMMALS/ 

POPULATION/ ACOUSTIC MONITORING 

Goold, J.C. and P.J. Fish. 1998. Broadband spectra of seismic survey air-gun emissions, 

with reference to dolphin auditory thresholds. J. Acoust. Soc. Am. 

103(4):2,177-2,184. 

Keywords: SEISMIC/ SURVEY/ DOLPHIN/ MARINE MAMMALS/ 

HEARING/ IMPACT/ TTS/ AUDITORY BEHAVIOR 

Govoni, J.J., L.R. Settle, and M.A. West. 2002. Investigation of impacts of underwater 

explosions on larval and early juvenile fishes. Part 2: Trauma to late-stage larval 

and early-juvenile pinfish, Lagodon rhomboides, and spot, Leiostomus xanthurus,

inflicted by sub-marine detonations. Report to U.S. Army Corps of Engineers, 

Wilmington District, Wilmington, NC. 

Keywords: CAGING EXPERIMENTS/ EXPLOSION EFFECTS/ FISH-KILL/ 

FISHES/ MARINE FISH/ LARVAL FISH/ ORGAN TRAUMA/ NORTH 

CAROLINA 

Greene, G.D., F.R. Engelhardt, and R.J. Paterson. 1985a. Criteria for determining 

acceptability of environmental effects. Pp. 380-383. In: Effects of explosives in 

the marine environment. Can. Oil & Gas Lands Admin., Environ. Prot. Br., 

Ottawa, Ont. Tech. Rep. 5. 

Keywords: BLASTING/ CRITERIA/ FISH/ IMPACT/ MARINE MAMMALS/ 

SEISMIC 

Greene, G.D., F.R. Engelhardt, and R.J. Paterson. 1985b. Measures for mitigating 

environmental effects. Pp. 374-376. In: Effects of explosives in the marine 

environment. Can. Oil & Gas Lands Admin., Environ. Prot. Br., Ottawa, Ont. 

Tech. Rep. 5. 

Keywords: BLASTING/ FISH/ IMPACT / MARINE MAMMALS/ 

MITIGATION/ SEISMIC 

Greene, G.D., F.R. Engelhardt, and R.J. Paterson. 1985c. Physical and biological 

monitoring. Pp. 377-379. In: Effects of explosives in the marine environment. 

Can. Oil & Gas Lands Admin., Environ. Prot. Br., Ottawa, Ont. Tech. Rep. 5. 

Keywords: BLASTING/ FISH/ IMPACT/ MARINE MAMMALS/ 

MONITORING/ SEISMIC 
A-17 

Greene, G.D., F.R. Engelhardt, and R.J. Paterson. 1985d. Proceedings of the workshop 

on explosives use in the marine environment, 29-31 January 1985, Can. Oil and 

Gas Lands Admin., Environ. Prot. Br., Ottawa, Ont. Tech. Rep. 5. 398 pp. 

Keywords: BIRDS/ BLASTING/ EFFECT/ FISH/ IMPACT/ MARINE 

MAMMALS/ MARINE/ NOISE/ SOUND/ UNDERWATER 

Greene, C.R., Jr. 1998a. Underwater acoustic noise and transmission loss during 

summer at BP’s Liberty prospect in Foggy Island Bay, Alaskan Beaufort Sea. 

Report from Greeneridge Sciences Inc., Santa Barbara, CA, and LGL Ltd., King 

City, Ontario for BP Exploration (Alaska) Inc., Anchorage, AK. Greeneridge 

Rep. 189-1. 39 pp. 

Keywords: ACOUSTICS/ UNDERWATER/ NOISE/ ALASKA/ 

UNDERWATER SOUND/ SOUND WAVES 

Greene, C.R., Jr. 1998b. Underwater sound waveforms and levels from a pulsed power 

device to deter pinnipeds. Report by Greeneridge Sciences Inc., Santa Barbara, 

CA for Pacific States Marine Fisheries Commission, Gladstone, OR. 19 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

PHYSICAL/ SONAR/ UNDERWATER 

Greene, C.R., Jr., N.S. Altman, and W.J. Richardson. 1999. The influence of seismic 

survey sounds on bowhead whale calling rates. J. Acoust. Soc. Am. 

106(4, Pt. 2):2,280. 

Keywords: BALEEN/ CALLS/ WHALE/ MARINE MAMMALS/ SEISMIC/ 

EFFECTS/ SOUND/ UNDERWATER 

Gulf of Mexico Fishery Management Council. 1998. Generic amendment for addressing 

essential fish habitat requirements in the following fishery management plans of 

the Gulf of Mexico: Shrimp fishery of the Gulf of Mexico, United States waters; 

red drum fishery of the Gulf of Mexico; reef fish fishery of the Gulf of Mexico; 

coastal migratory pelagic resources (mackerels) in the Gulf of Mexico and South 

Atlantic; stone crab fishery of the Gulf of Mexico; spiny lobster in the Gulf of 

Mexico and South Atlantic; coral and coral reefs of the Gulf of Mexico (includes 

environmental assessment). U.S. Dept. of Commerce, National Oceanic and 

Atmospheric Administration, Gulf of Mexico Fishery Management Council, 

Tampa, FL, NOAA Award Number NA87FC0003. 

Keywords: GULF OF MEXICO/ MARINE FISH/ FISHERY MANAGEMENT 

Hadžiselimović, H. and M. Andelić. 1967. Contribution to the knowledge of the ear in 

the sea turtle. Acta. Anat. 66:460-477. 

Keywords: MARINE TURTLES/ EAR/ ANATOMY 

Hall, J.D. and C.S. Johnson. 1972. Auditory thresholds of a killer whale Orcinus orca

Linnaeus. J. Acoust. Soc. Am. 51(2):515-517. 

Keywords: KILLER/ MARINE MAMMALS / ODONTOCETES/ IMPACT/ 

NOISE/ EFFECT/ ACOUSTICS/ TTS 
A-18 

Hannay, D. and R. Racca. 2000a. Appendix D: Modeling blast parameters for the DET 

test: Effects on marine mammals and fish. p. 16. In: U.S. Navy Environmental 

Assessment for the distributed explosive technology (DET) system at San 

Clemente Island, California. Naval Sea Systems Command, Program Executive 

Officer for Mine Warfare (PMS 407), Washington, DC. 

Keywords: BLASTING/ DAMAGE/ DISTURBANCE/ EFFECT/ FISH / 

IMPACT/ MARINE MAMMALS/ NAVY/ NOISE/ PHYSICAL/ TTS/ 

UNDERWATER 

Hannay, D. and R. Racca. 2000b. Appendix D: Modeling blast parameters for the 

SABRE test: Effects on marine mammals and fish. p. 16. In: U.S. Navy 

Environmental Assessment for the shallow water assault breaching (SABRE) 

system at San Clemente Island, California. Naval Sea Systems Command, 

Program Executive Officer for Mine Warfare (PMS 407), Washington, DC. 

Keywords: BLASTING/ DAMAGE/ DISTURBANCE/ EFFECT/ FISH/ 

IMPACT/ MARINE MAMMALS/ NAVY/ NOISE/ PHYSICAL/ TTS/ 

UNDERWATER 

Hannay, D.E. 1995. Estimation of geoacoustic parameters of the ocean bottom by 

inversion of reflection loss data. M.S. Thesis, University of Victoria, Victoria, 

BC, Canada. 

Keywords: LAYERED MEDIA/ PRESSURE-TIME HISTORIES/ SPECTRAL 

LEVELS/ UNDERWATER ACOUSTICS/ UNDERWATER EXPLOSIONS 

Hannay, D.E. and N.R. Chapman. 1999. Source levels for shallow underwater sound 

charges. J. Acoust. Soc. Am. 105(1):260-263. 

Keywords: BUBBLE PULSE / UNDERWATER EXPLOSIONS/ ACOUSTICS/ 

SOUND WAVES/ SHALLOW WATER/ WAVE REFLECTION 

Hawkins, A.D. 1986. Underwater sound and fish behavior. Pp. 114-151. In: T. Pitcher 

(ed.). The behavior of Teleost Fishes. Baltimore, MD: The Johns Hopkins 

University Press. 

Keywords: ACOUSTIC BEHAVIOR / ACOUSTICS/ AUDITORY 

BEHAVIOR/ BEHAVIOR/ FISHES/ HEARING 

Heathcote, T.B. 1981. An experimental program to determine the environmental impact 

of explosive removal of oil wellheads: Progress report. Naval Surface Weapons 

Center, White Oak Lab, Silver Spring, MD. 27 pp. 

Keywords: EXPLOSIVE PLATFORM REMOVAL/ EXPLOSIVE 

STRUCTURE REMOVAL/ EXPLOSIVES 

Helweg, D.A., J.B. Gaspin, and J.A. Goertner. 1998. Criteria for marine mammal 

auditory threshold shift: Appendix E, Final environmental impact statement: 

Shock testing the SEAWOLF submarine. SPAWARSYSCEN, San Diego, CA. 

Keywords: BLASTING/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS/ NOISE/ SOUND/ TTS 
A-19 

Hempen, G.L. and T.M. Keevin. 1995. Underwater blasting effects models: A critical 

evaluation of IBLAST. Proceedings of the Twenty-first Annual Conference on 

Explosives and Blasting Technique (Vol 1), Nashville Tennessee, International 

Society of Explosive Engineers, Cleveland, OH. 

Keywords: ENVIRONMENTAL EFFECTS/ LETHAL RANGES/ 

MATHEMATICAL MODELS/ UNDERWATER EXPLOSIONS/ CHARGE 

SIZE/ FISH MORTALITY/ UNDERWATER EXPLOSIONS 

Hempen, G.L. and T.M. Keevin. 1997. Underwater pressure recording: Industry 

standardization. Proceedings of the Twenty-third Annual Conference on 

Explosives and Blasting Technique (Vol 1), Las Vegas, Nevada, International 

Society of Explosive Engineers, Cleveland, OH. 

Keywords: PRESSURE MEASUREMENT/ UNDERWATER EXPLOSIONS 

Henwood, T. 1988. National Marine Fisheries Service perspective on structure 

removals. Pp. 300-303. In: Minerals Management Service Proceedings: Eighth 

Annual Gulf of Mexico Information Transfer Meeting, December 1987. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico Region, 

New Orleans, LA. OCS Study MMS 88-0035. 

Keywords: EXPLOSIVE PLATFORM REMOVALS/ MARINE TURTLES/ 

ENVIRONMENTAL EFFECTS/ NATIONAL MARINE FISHERIES SERVICE 

Notes: MMS Contract No. 14-12-0001-30305 

Hill, S.H. 1978. A guide to the effects of underwater shock waves on Arctic marine 

mammals and fish. Institute of Marine Sciences, Patricia Bay, Sidney, B.C. 

Pacific Marine Science Report 78-26. 50 pp. 

Keywords: PRESSURE EFFECTS/ MARINE MAMMALS/ SOUND WAVES/ 

FISHES/ MARINE FISH/ MATHEMATICAL MODELS/ LETHAL RANGES/ 

BLASTING/ UNDERWATER EXPLOSIONS/ ARCTIC/ FISH MORTALITY/ 

SHOCK WAVES 

Hirsch, A.E. and A.K. Ommaya. 1972. Head injury caused by underwater explosion of a 

firecracker. J. Neurosurg. 37(1):95-99. 

Keywords: HUMAN INJURY/ SAFE RANGES/ UNDERWATER 

EXPLOSIONS/ EFFECTS/ MORTALITY CAUSE 

Hirth, H.H. 1997. Synopsis of biological data on the green turtle, Chelonia mydas

(Linnaeus 1758). Report to the U.S. Dept. of the Interior, Fish and Wildlife 

Service, Washington, DC. Biological Report 97(1). 120 pp. 

Keywords: MARINE TURTLES/ GREEN TURTLE/ CHELONIA MYDAS/ 

NATURAL HISTORY 

Hooker, S.K. 1999. Resource and habitat use of northern bottlenose whales in the Gully: 

Ecology, diving and ranging behaviour. Ph.D. thesis, Dalhousie University, 

Halifax, NS. 211 pp. 

Keywords: BOTTLENOSE/ ODONTOCETES/ MARINE MAMMALS/ 

BEHAVIOR/ ECOLOGY/ HABITAT UTILIZATION/ ATLANTIC 
A-20 

Hubbs, C.L. and A.B. Rechnitzer. 1952. Report on experiments designed to determine 

effects of underwater explosions on fish life. Cal. Fish and Game 38:333-366. 

Keywords: CALIFORNIA/ EXPLOSIVE CHARGE DESIGN/ FISH-KILL/ 

FISHES/ MARINE FISH/ MORTALITY CAUSE/ MORTALITY CRITERIA/ 

ACOUSTICS/ BLASTING/ EFFECT/ FISH/ IMPACT/ JETTED/ SOUND 

Hubbs, C.L., E.P. Schultz, and R.L. Wisner. 1960. Preliminary report on investigations 

of the effects on caged fishes of underwater nitrocarbonitrate explosions, Data 

Report. University of California, Scripps Institute of Oceanography. 21 pp. 

Keywords: CALIFORNIA/ EXPLOSIVE CHARGE DESIGN/ FISH-KILL/ 

FISHES/ MARINE FISH/ MORTALITY CAUSE/ MORTALITY CRITERIA 

Jefferson, T.A. and B.E. Curry. 1994. Review and evaluation of potential acoustic 

methods of reducing or eliminating marine mammal-fishery interactions. Report 

by Marine Mammal Research Program, Texas A&M Univ., College Station, TX 

for Marine Mammal Commission, Washington, DC. NTIS PB 95 100384. 59 pp. 

Keywords: ACOUSTICS/ AHD/ BLASTING/ DETERRENT/ DISTURBANCE/ 

EFFECT/ FISHERY/ INTERACTION/ MARINE MAMMALS/ NOISE/ 

UNDERWATER 

Johnson, C.S. 1967. Sound detection thresholds in marine mammals. Pp. 247-260. In: 

W.N. Tavolga (ed.). Marine Bio-acoustics, Vol. 2. Oxford, U.K.: Pergamon. 

 353 pp. 

Keywords: DOLPHIN/ NOISE/ MARINE MAMMALS/ SOUND/ HEARING/ 

WHALE 

Johnson, C.S. 1968. Masked tonal thresholds in the bottlenosed porpoise. J. Acoust. 

Soc. Am. 44(4):965-967. 

Keywords: PORPOISE/ MARINE MAMMALS/ TTS/ ACOUSTICS/ 

HEARING/ NOISE/ EFFECT 

Jones, F.R.H. 1951. The swimbladder and vertical movements of teleostean fishes. I. 

Physical factors. J. Exp. Biol. 28:553-566. 

Keywords: ANATOMY/ FISHES/ PHYSIOLOGY/ SWIMBLADDER/ 

SWIMBLADDER FISH 

Jones, F.R.H. 1952. The swimbladder and vertical movements of teleostean fishes. II. 

The restriction to rapid and slow movements. J. Exp. Biol. 29:94-109. 

Keywords: ANATOMY/ FISHES/ PHYSIOLOGY/ SWIMBLADDER/ 

SWIMBLADDER FISH 

Jones, F.R.H. and N.B. Marshall. 1953. The structure and function of the teleostean 

swimbladder. Biol. Rev. 28:16-83. 

Keywords: SWIMBLADDER/ ANATOMY/ FISHES/ PHYLOGENY/ 

PRESSURE EFFECTS/ SWIMBLADDER FISH 
A-21 

Kaiser, M.J., D.V. Mesyanzhinov, and A.G. Pulsipher. 2002. Explosive removals of 

offshore structures in the Gulf of Mexico. Ocean Coast. Manage. 45(8):459-483. 

Keywords: OFFSHORE STRUCTURES/ EXPLOSIVE PLATFORM 

REMOVAL/ BLASTING/ GULF OF MEXICO 

Kastak, D., R.J. Schusterman, B.L. Southall, and C.J. Reichmuth. 1999. Underwater 

temporary threshold shift induced by octave-band noise in three species of 

pinniped. J. Acoust. Soc. Am. 106(2):1,142-1,148. 

Keywords: EFFECT/ ELEPHANT/ HARBOR/ IMPACT/ NOISE/ SEA LION/ 

SEAL/ TTS/ UNDERWATER 

Keevin, T.M. 1998. A review of Natural Resource Agency recommendations for 

mitigating the impacts of underwater blasting. Reviews in Fish Science 

6(4):281-313. 

Keywords: ENVIRONMENT MANAGEMENT/ ENVIRONMENTAL 

LEGISLATION/ NATURE CONSERVATION/ FISHERY MANAGEMENT/ 

INLAND FISHERIES/ UNDERWATER EXPLOSIONS/ PERMITS/ USA/ 

CHARGE SIZE 

Keevin, T.M. and G.L. Hempen. 1997. The environmental effects of underwater 

explosions with methods to mitigate impacts. U.S. Army Corps of Engineers, St. 

Louis, MO. 

Keywords: UNDERWATER EXPLOSIONS/ BLASTING/ ENVIRONMENTAL 

IMPACT/ SHOCK WAVE/ BUBBLE PULSE 

Kemp, R.J. 1956. Do seismic studies affect marine life. Texas Game and Fish 14:11-13. 

Keywords: EXPLOSION EFFECTS/ FISH-KILL/ FISHES/ CAGING 

EXPERIMENTS/ UNDERWATER EXPLOSIONS 

Ketten, D.R. 1995. Estimates of blast injury and acoustic trauma zones for marine 

mammals from underwater explosions. Pp. 391-407. In: R.A. Kastelein, J.A. 

Thomas, and P.E. Nachtigall (eds.). Sensory Systems of Aquatic Mammals. 

Worden, The Netherlands: De Spil Publishers. 

Keywords: UNDERWATER EXPLOSIONS/ MARINE MAMMALS/ 

BLASTING 

Ketten, D.R. 1997. Experimental measures of blast and acoustic trauma in marine 

mammals. U.S. Department of Commerce, National Oceanic and Atmospheric 

Administration, National Marine Fisheries Service, Southwest Fisheries Science 

Center, La Jolla, CA. http://swfsc.ucsd.edu/PRD/dsweb/moreinfo/blast.htm. 

Keywords: BLASTING/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS 
A-22 

Ketten, D.R. 1998a. Marine mammal auditory systems: A study of audiometric and 

anatomical data and its implications for underwater acoustic impacts. U.S. Dept. 

of Commerce, National Oceanic and Atmospheric Administration, Natl. Mar. 

Fish. Serv., Southwest Fisheries Science Center, La Jolla, CA. 

NOAA-TM-NMFS-SWFSC SWFSC-256. 74 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MAMMAL/ MARINE 

MAMMALS/ MARINE/ NOISE/ SEAL/ TTS/ UNDERWATER/ WHALE 

Ketten, D.R. 1998b. Marine mammal auditory systems: A summary of audiometric and 

anatomical data and its implications for underwater acoustic impacts. U.S. Dept. 

of Commerce, National Oceanic and Atmospheric Administration, Natl. Mar. 

Fish. Serv., Southwest Fisheries Science Center, La Jolla, CA. NOAA Tech. 

Memo. NOAA-TM-NMFS-SWFSC-256. 74 pp. 

Keywords: MARINE MAMMALS/ ACOUSTICS/ EFFECTS 

Ketten, D.R. 1998c. Marine mammal hearing and acoustic trauma: basic mechanisms, 

marine adaptations, and beaked whale anomalies. Pp. 2-61-2-71. In: A. D'Amico 

and W. Verboom (eds.). Report of the Bioacoustics Panel. NATO/SCALANT, 

La Spieza. 

Keywords: BLASTING/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS 

Ketten, D.R. 2000. Cetacean ears. Pp. 43-108. In: W.W.L. Au, A.N. Popper, and R.R. 

Fay (eds.). Hearing by Whales and Dolphins. New York: Springer-Verlag. 

Keywords: BLASTING/ DAMAGE/ HEARING/ MARINE MAMMALS/ 

NAVY / PTS/ SONAR/ TTS/ WHALE 

Ketten, D.R., J. Lien, and S. Todd. 1993. Blast injury in humpback whales ears: 

Evidence and implications. J. Acoust. Soc. Am. 94(3, Pt. 2):1,849-1,850. 

Keywords: BLASTING/ EFFECT/ HEARING/ HUMPBACK/ IMPACT/ 

MARINE MAMMALS/ SEISMIC/ WHALE 

Ketten, D.R., J. O'Malley, P.W.B. Moore, and S. Ridgway. 2001. Aging, injury, disease 

and noise in marine mammal ears. J. Acoust. Soc. Am. 110(5, Pt. 2):2,721. 

Keywords: BOTTLENOSE/ DAMAGE/ DISTURBANCE/ EFFECT/ 

HEARING/ IMPACT/ MARINE MAMMALS/ NOISE/ SEAL/ SOUND/ 

UNDERWATER/ WHALE 

Ketten, D.R., J. Arruda, S. Cramer, J.O. O'Malley, J. Reidenberg, and S. McCall. 2003. 

Experimental measures of blast trauma in marine mammals. p. 30. In: R. Gisner 

(ed.). Environmental consequences of underwater sound, 12-16 May 2003. 

Office of Naval Research, Life Sciences Research Office, Bethesda, MD. 

Keywords: BLASTING/ DAMAGE/ EFFECT/ IMPACT/ LABORATORY/ 

MARINE MAMMALS/ NOISE/ ODONTOCETES/ UNDERWATER 
A-23 

Klima, E.F., G.R. Gitschlag, and M.L. Renaud. 1988. Impacts of the explosive removal 

of offshore petroleum platforms on sea turtles and dolphins. Mar. Fish. Rev. 

50(3):33-42. 

Keywords: ACOUSTICS / BLASTING/ MARINE MAMMALS/ MARINE 

TURTLES/ EXPLOSIVE REMOVAL/ OFFSHORE PLATFORMS 

Konya, C.J. and E.J. Walter. 1985. Seminar on Blasting and Overbreak Control (rock 

blasting). U.S. Department of Transportation, Federal Highway Administration, 

National Technical Information Service, Springfield, VA. 

Keywords: BLASTING/ CONTROLLED EXPLOSIONS/ DETONATION 

Koski, W.R., J.W. Lawson, D.H. Thomson, and W.J. Richardson. 1998. Point Mugu sea 

range technical report. Rep. by LGL Limited, King City, ON and Ogden 

Environmental Energy Services, Santa Barbara, CA for U.S. Navy Naval Air 

Warfare Center, Weapons Division, Point Mugu, CA and Southwest Division 

Naval Facilities Engineering Command, San Diego, CA. 281 pp. 

Keywords: ABUNDANCE/ AIRCRAFT/ BLASTING/ CALIFORNIA / 

DISTRIBUTION/ IMPACT/ MARINE MAMMALS/ NAVY/ NOISE/ PACIFIC/ 

SHIPPING/ SONAR/ UNDERWATER 

Kryter, K.D. 1985. The Effects of Noise on Man. 2nd ed. Orlando, FL: Academic 

Press. 688 pp. 

Keywords: DAMAGE/ HEARING/ HUMAN/ PTS/ TTS 

Kryter, K.D. 1994. The Handbook of Hearing and the Effects of Noise: Physiology, 

Psychology, and Public Health. San Diego, CA: Academic Press. 

Keywords: HEARING/ ACOUSTICS/ NOISE/ EFFECT/ TERRESTRIAL 

MAMMALS/ PTS/ TTS 

Landsberg, P.G. 2000. Underwater blast injuries. Trauma and Emergency Medicine 

17(2). http://www.scuba-doc.com. 

Keywords: BLASTING/ EFFECT/ HUMAN/ IMPACT/ MARINE MAMMALS/ 

UNDERWATER 

Larkman, V.E. and R.R. Veit. 1998. Seasonality and abundance of blue whales off 

southern California. CalCOFI Rep. 39:236-239. 

Keywords: BLUE/ MARINE MAMMALS/ ABUNDANCE/ CALIFORNIA 

Lawler, Matusky, and Skelly Engineers LLP. 2002. Impact assessment and mitigation 

plan for blasting on the millenium pipeline Haverstraw Bay crossing. Lawler, 

Matusky, and Skelly Engineers LLP, Pearl River, NY. 

Keywords: BLASTING/ BURIED CHARGES/ CHARGE SIZE/ 

ENVIRONMENTAL IMPACT/ ENVIRONMENTAL MANAGEMENT/ 

NUMERICAL MODELING/ UNDERWATER EXPLOSIONS 
A-24 

Leatherwood, S. and R.R. Reeves. 1989. Marine mammal research and conservation in 

Sri Lanka 1985-1986. Mar. Mamm. Tech. Rep. 1. United Nations Environ. 

Prog., Oceans & Coastal Areas Prog. Activ. Cent., Nairobi, Kenya. 138 pp. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ CONSERVATION/ 

SRI LANKA 

Lenhardt, M.L. 1982. Bone conduction hearing in turtles. J. Aud. Res. 22:153-160. 

Keywords: MARINE TURTLES/ BONE CONDUCTED HEARING 

Lenhardt, M.L. and S.W. Harkins. 1983. Turtle shell as an auditory receptor. J. Aud. 

Res. 23:251-260. 

Keywords: MARINE TURTLES/ BONE CONDUCTED HEARING 

Lenhardt, M.L., S. Bellmund, R.A. Byles, S.W. Harkins, and J.A. Musick. 1983. Marine 

turtle reception of bone-conducted sound. J. Aud. Res. 23:119-125. 

Keywords: MARINE TURTLES/ BONE CONDUCTED HEARING/ 

LOGGERHEAD TURTLE/ CARETTA CARETTA/ KEMP'S RIDLEY/ 

LEPIDOCHELYS KEMPII/ AUDITORY BRAINSTEM RESPONSE 

Lenhardt, M.L., R.C. Klinger, and J.A. Musick. 1985. Marine turtle middle-ear 

anatomy. J. Aud. Res. 25:66-72. 

Keywords: MARINE TURTLES/ GREEN TURTLE/ CHELONIA MYDAS/ 

EAR/ ANATOMY 

Lenhardt, M.L., S.E. Moein, J.A. Musick, and D. Barnard. 1994. Evaluation of the 

response of loggerhead sea turtles (Caretta caretta) to a fixed sound source. U.S. 

Army Corps of Engineers Waterways Experiment Station. 15 pp. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ HOPPER DREDGES/ ACOUSTICS/ ACOUSTIC BEHAVIOR 

Lewis, J.A. 1996. Effects of underwater explosions on life in the sea. Defense Science 

and Technology Organization, Aeronautical and Maritime Research Laboratory, 

Melbourne. DSTO-GD-0080. 39 pp. 

Keywords: UNDERWATER EXPLOSIONS 

Liem, K.F. 1988. Form and function of lungs: The evolution of air breathing 

mechanisms. Am. Zool. 28:739-759. 

Keywords: AIR/ PHYSIOLOGY/ EVOLUTION 

Lien, J., S. Todd, P. Stevick, F. Marques, and D. Ketten. 1993. The reaction of 

humpback whales to underwater explosions. J. Acoust. Soc. Am. 

94(3, Pt. 2):1,849. 

Keywords: BEHAVIOR/ BLASTING/ EFFECT/ HEARING/ HUMPBACK/ 

IMPACT/ MARINE MAMMALS 
A-25 

Lien, J., D.G. Taylor, and D. Borggaard. 1995. Management of underwater explosions 

in areas of high whale abundance. MARINEV '95 International conference on 

Technologies for Marine Preservation, 24-29 September, 1995, Tokyo, Japan. 

The Society of Naval Architects of Japan, Tokyo. 

Keywords: BLASTING/ EFFECT/ HUMPBACK/ IMPACT/ MARINE 

MAMMALS/ MITIGATION/ SEISMIC/ UNDERWATER/ WHALE 

Linton, T.S., A.M. Landry Jr., J.F. Buckner, Jr., and R.L. Berry. 1985. Effects upon 

selected marine organisms of explosives used for sound production in geophysical 

exploration. T. Journal of Science 37:341-353. 

Keywords: CAGING EXPERIMENTS/ FISH-KILL/ FISHES/ LETHAL 

RANGES/ MARINE FISH/ SHOCK WAVES/ SHOCK WAVES/ 

SWIMBLADDER FISH/ TEXAS/ MORTALITY CAUSE 

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers. 1989. Are sea turtles 

attracted to petroleum platforms? Pp. 103-104. In: S.A. Eckert, K.L. Eckert, and 

T.H. Richardson (comps.). Proceedings of the Ninth Annual Workshop on Sea 

Turtle Conservation and Biology, 7-11 February 1989, Jekyll Island, Georgia. 

NOAA Tech. Memo. NMFS-SEFSC 232. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ OFFSHORE 

PLATFORMS/ MINERALS MANAGEMENT SERVICE 

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers. 1990. Association of 

sea turtles with petroleum platforms in the north-central Gulf of Mexico. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Regional Office, New Orleans, LA. OCS Study MMS 90-0025. 90 pp. 

Keywords: MARINE TURTLES/ GULF OF MEXICO/ OFFSHORE 

PLATFORMS/ MINERALS MANAGEMENT SERVICE/ NATIONAL 

MARINE FISHERIES SERVICE/ SURVEYS 

Love, M., J. Hyland, A. Ebling, T. Herrlinger, A. Brooks, and E. Imamura. 1994. A 

pilot study of the distribution and abundances of rockfishes in relation to natural 

environmental factors and an offshore oil and gas production platform off the 

coast of southern California. Bull. Mar. Sci. 55:1,062-1,085. 

Keywords: CALIFORNIA/ MARINE FISH/ OFFSHORE OIL AND GAS/ 

OFFSHORE PLATFORMS/ ROCKFISH 

Love, M.S., M. Nishimoto, D. Schroeder, and J. Caselle. 1999. The ecological role of 

natural reefs and oil and gas production platforms on rocky reef fishes in southern 

California: Final interim report. U.S. Dept. of the Interior, U.S. Geological 

Survey, Biological Resources Division. USGS/ BRD/ CR-1999-007. 208 pp. 

Keywords: CALIFORNIA/ MARINE FISH/ OFFSHORE OIL AND GAS/ 

OFFSHORE PLATFORMS/ ROCKFISH 
A-26 

Love, M.S., J.E. Caselle, and L. Snook. 2000. Fish assemblages around seven oil and 

gas platforms in the Santa Barbara Channel area. Fish. Bull. 98(1):96-117. 

Keywords: CALIFORNIA/ MARINE FISH/ OFFSHORE OIL AND GAS/ 

OFFSHORE PLATFORMS/ ROCKFISH 

Love, M.S., M. Nishimoto, and D. Schroeder. 2001. The ecological role of natural reefs 

and oil and gas production platforms on rocky reef fishes in southern California: 

1998-1999 survey report. U.S. Dept. of the Interior, U.S. Geological Survey, 

Biological Resources Division, Seattle, Washington 98104. OCS Study MMS 

2001-028. 115 pp. 

Keywords: CALIFORNIA/ MARINE FISH/ OFFSHORE OIL AND GAS/ 

OFFSHORE PLATFORMS/ ROCKFISH 

MacGillivray, A.O., D.E. Hannay, and S.A. Carr. 2002. Acoustic Monitoring Results 

from the Anderson Resources 2001 Beaufort Sea Marine Seismic Program. 

December 2002. JASCO Research Ltd. 

Keywords: ACOUSTIC MONITORING/ CANADA/ ENVIRONMENTAL 

IMPACT/ BEAUFORT SEA/ UNDERWATER ACOUSTICS 

MacGillivray, A.O., M.E. Austin, and D.E. Hannay. 2003. Acoustic Monitoring of 

WesternGeco 2002 Mackenzie River Seismic Project. Report for WesternGeco 

Ltd. by JASCO Research Ltd. 

Keywords: ACOUSTIC MONITORING/ CANADA/ ENVIRONMENTAL 

IMPACT/ MACKENZIE RIVER/ UNDERWATER ACOUSTICS 

Madsen, P.T., B. Mohl, B.K. Nielsen, and M. Wahlberg. 2002. Male sperm whale 

behaviour during exposures to distant seismic survey pulses. Aquat. Mamm. 

28(3):231-240. 

Keywords: EXPLORATION/ GAS/ IMPACT/ MARINE MAMMALS/ NOISE/ 

OIL/ SEISMIC/ SOUND/ SPERM/ UNDERWATER/ WHALE 

Majors, A.P. 1990. Effects of noise on animals: Implications for dolphins exposed to 

seal bombs in the eastern tropical Pacific purse-seine fishery an Annotated 

bibliography. Admin. Rep. LJ-90-06 Southwest Fisheries Sciences Center, 

National Marine Fisheries Service, La Jolla, CA. 55 pp. 

Keywords: BLASTING/ DOLPHIN/ FISHERY/ IMPACT/ INTERACTION/ 

MARINE MAMMALS/ WHALE 

Malme, C.I. 1993. Prediction of potential disturbance of baleen whales by lowfrequency acoustic transients. Paper 4pAB9. Abstract in J. Acoust. Soc. Am. 

94(3, Pt. 2):1,850. Presented at the 126th Meeting of the Acoustical Society of 

America, Denver, CO. 5 pp. 

Keywords: BALEEN/ BLASTING/ EFFECT/ EXPLORATION/ IMPACT/ OIL/ 

SEISMIC / SOUND/ UNDERWATER/ WHALE 
A-27 

Malme, C.I. and P.R. Miles. 1985. Behavioral responses of marine mammals (gray 

whales) to seismic discharges. Pp. 253-280. In: G.D. Greene, F.R. Engelhardt, 

and R.J. Patterson (eds.). Proceedings Workshop on effects of explosives use in 

the marine environment, January 1985, Halifax, NS. Can. Oil and Gas Lands 

Admin., Environ. Prot. Br., Ottawa, Ont. Tech. Rep. No. 5. 398 pp. 

Keywords: GRAY/ WHALE/ MARINE MAMMALS/ AUDITORY 

BEHAVIOR/ NOISE/ IMPACT/ EFFECT/ HEARING 

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird. 1983. Investigations of 

the potential effects of underwater noise from petroleum industry activities on 

migrating gray whale behavior. Report from Bolt Beranek & Newman Inc., 

Cambridge, MA for U.S. Minerals Management Service, Anchorage, AK. NTIS 

PB86-174174. BBN Rep. 5366. var. pp. 

Keywords: DISTURBANCE/ EXPLORATION/ GAS/ OIL/ BALEEN/ 

MARINE MAMMALS/ NOISE/ SOUND/ IMPACT/ UNDERWATER/ WHALE 

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird. 1984. Investigations of 

the potential effects of underwater noise from petroleum industry activities on 

migrating gray whale behavior/Phase II: January 1984 migration. Report from 

Bolt Beranek & Newman Inc., Cambridge, MA for U.S. Minerals Management 

Service, Anchorage, AK. NTIS PB86-218377. BBN Rep. 5586. var. pp. 

Keywords: DISTURBANCE / EXPLORATION/ GAS/ BALEEN/ MARINE 

MAMMALS/ NOISE/ SOUND/ IMPACT/ UNDERWATER/ WHALE 

Malme, C.I., B. Würsig, J.E. Bird, and P. Tyack. 1988. Observations of feeding gray 

whale responses to controlled industrial noise exposure. Pp. 55-73. In: W.M. 

Sackinger, M.O. Jeffries, J.L. Imm, and S.D. Treacy (eds.). Port and Ocean 

Engineering under Arctic Conditions, Vol. II. Geophys. Inst., Univ. Alaska, 

Fairbanks, AK. 

Keywords: BALEEN/ MARINE MAMMALS/ NOISE/ SOUND/ IMPACT/ 

UNDERWATER/ WHALE 

Maples, L.C. 1976. The shock wave revisited - A second look at some measurements of 

explosive acoustic source levels. Naval Underwater Systems Center, New 

London Laboratory, New London, CT. TM No. TA1-80-76. 

Keywords: PRESSURE MEASUREMENT/ SHOCK WAVES/ SPECTRAL 

LEVELS/ UNDERWATER EXPLOSIONS 

Maples, L.C. and W.H. Thorp. 1976. Measurements of some characteristics of the shock 

wave from small TNT charges in the deep ocean. Naval Underwater Systems 

Center, New London Laboratory, New London, CT. TM No. 313-10-76. 

Keywords: PRESSURE MEASUREMENT/ PRESSURE-TIME HISTORIES/ 

SHOCK WAVE/ SPECTRAL LEVELS/ UNDERWATER EXPLOSIONS 
A-28 

Marquez, R.M. 1990. FAO species catalog. Vol. 11: Sea turtles of the world. An 

annotated and illustrated catalog of sea turtle species known to date. FAO, Rome. 

FAO Fisheries Synopsis, No. 125, Vol. 11. 81 pp. 

Keywords: MARINE TURTLES / NATURAL HISTORY 

Marshall, W.J. 1998. Acoustical properties of end-initiated line charges. J. Acoust. Soc. 

Am. 103(5):2,366-2,376. 

Keywords: BLASTING/ LINE/ PHYSICAL/ PROPAGATION/ 

UNDERWATER 

Mate, B.R., K.M. Stafford, and D.K. Ljungblad. 1994. A change in sperm whale 

(Physter macrocephalus) distribution correlated to seismic surveys in the Gulf of 

Mexico. J. Acoust. Soc. Am. 96(5, Pt 2.):3,268-3,269. 

Keywords: EFFECT/ GULF OF MEXICO/ IMPACT/ MARINE MAMMALS/ 

NOISE/ SEISMIC/ SPERM/ UNDERWATER/ WHALE 

McCauley, R.D., M.N. Jenner, C. Jenner, K.A. McCabe, and J. Murdoch. 1998. The 

response of humpback whales (Megaptera novaeangliae) to offshore seismic 

survey noise: Preliminary results of observations about a working seismic vessel 

and experimental exposures. APPEA J. 1998:28-43. 

Keywords: BEHAVIOR/ MARINE MAMMALS/ BLASTING/ 

DEVELOPMENT/ EFFECT/ GAS/ OIL/ HUMPBACK/ WHALE/ IMPACT/ 

NOISE/ SEISMIC/ UNDERWATER 

McCauley, R.D., J. Fretwell, A.J. Duncan, C. Jenner, M.N. Jenner, J.D. Penrose, R.I.T. 

Prince, A. Adhitya, J. Murdoch, and K.A. McCabe. 2000. Marine seismic 

surveys - A study of environmental implications. APPEA J. 40:692-708. 

Keywords: SEISMIC / NOISE/ IMPACT/ SURVEY/ ENVIRONMENTAL 

IMPACT/ UNDERWATER/ EFFECTS 

McCauley, R.D., J. Fretwell, and A.N. Popper. 2003. High intensity anthropogenic 

sound damages fish ears. J. Acoust. Soc. Am. 113(1):638-642. 

Keywords: HEARING/ ANATOMY/ EFFECTS/ FISHES/ SUB-LETHAL 

McManus, J.W., R.B. Reyes, and C.L. Nañola. 1997. Effects of some destructive fishing 

methods on coral cover and potential rates of recovery. Environmental 

Management 21(1):69-78. 

Keywords: DYNAMITE FISHING/ ENVIRONMENTAL EFFECTS/ 

EXPLOSION EFFECTS/ HABITAT EFFECTS 

Mecklenburg, C.W., T.A. Mecklenburg, and L.K. Thorsteinson. 2002. Fishes of Alaska. 

American Fisheries Society, Bethesda, MD. 1,037 pp. 

Keywords: MARINE FISH/ ALASKA/ STOCK 

Metzger, R.J. and P.L. Shafland. 1986. Use of detonating cord for sampling fish. North 

American Journal of Fisheries Management 6:113-118. 

Keywords: FISHES/ SAMPLING/ UNDERWATER EXPLOSIVES 
A-29 

Miller, G.W., R.E. Elliott, W.R. Koski, V.D. Moulton, and W.J. Richardson. 1999. 

Whales (1998). Pp. 5-1 to 5-109. In: W.J. Richardson (ed.). Marine mammal 

and acoustical monitoring of Western Geophysical's open-water seismic program 

in the Alaskan Beaufort Sea, 1998. Rep. from LGL Ltd., King City, Ont., and 

Greeneridge Sciences, Inc., Santa Barbara, CA, for Western Geophysical, 

Houston TX, and U.S. Natl. Mar. Fish. Serv., Anchorage, AK, and Silver Spring, 

MD. LGL Rep. TA2230-3. 390 pp. 

Keywords: ALASKA/ BOWHEAD/ EFFECT/ IMPACT/ MARINE 

MAMMALS/ NOISE/ SEISMIC/ SOUND/ UNDERWATER/ WHALE 

Miller, J.D. 1997. Reproduction in sea turtles. Pp. 51-82. In: P.L. Lutz and J.A. Musick 

(eds.). The Biology of Sea Turtles. Boca Raton, FL: CRC Press. 

Keywords: MARINE TURTLES/ REPRODUCTION 

Minerals Management Service. 1987. Structural removal activities, Central and Western 

Gulf of Mexico Planning Areas - Programmatic environmental assessment. U.S. 

Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. OCS EIS/ EA MMS 87-0002. 

Keywords: OFFSHORE STRUCTURE REMOVAL/ GULF OF MEXICO/ 

WELLHEAD SEVERANCE/ OFFSHORE STRUCTURES 

Minerals Management Service. 1996. Cook Inlet Planning Area Oil and Gas Lease Sale 

149, Final Environmental Impact Statement. U.S. Dept. of Interior, Minerals 

Management Service, Alaska OCS Region. 

Keywords: OIL AND GAS INDUSTRY/ MARINE MAMMALS/ ALASKA 

Minerals Management Service and California State Lands Commission. 1997. 

Decommissioning and removal of oil and gas facilities offshore California: 

Recent experiences and future deepwater challenges. Proceedings of a Public 

Workshop, 23-25 September 1997, Ventura, CA. 196 pp. 

Keywords: OFFSHORE STRUCTURE REMOVAL/ CALIFORNIA/ 

WELLHEAD SEVERANCE/ OFFSHORE STRUCTURES 

Moein, S., M. Lenhardt, D. Barnard, J. Keinath, and J. Musick. 1993. Marine turtle 

auditory behavior. J. Acoust. Soc. Am. 93(4, Pt.2):2,378. 

Keywords: MARINE TURTLES/ ACOUSTICS/ HEARING/ AUDITORY 

BRAINSTEM RESPONSES 

Moein, S.E., J.A. Musick, and M.L. Lenhardt. 1994. Auditory behavior of the 

loggerhead sea turtle (Caretta caretta). p. 89. In: K.A. Bjorndahl, A.B. Bolten, 

D.A. Johnson, and P.J. Eliazar (comps.). Proceedings of the Fourteenth Annual 

Symposium on Sea Turtle Biology and Conservation. NOAA Tech. Memo. 

NMFS-SEFSC-351. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ AUDITORY BEHAVIOR / BONE CONDUCTED HEARING 
A-30 

Moein, S.M. 1994. Auditory evoked potentials of the loggerhead sea turtle (Caretta 

caretta). M.S. Thesis, College of William and Mary. 66 pp. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ HOPPER DREDGES/ AUDITORY REPULSION/ ACOUSTICS/ 

AUDITORY EVOKED POTENTIALS 

Mueter, F.J. and B.L. Norcross. 2002. Spatial and temporal patterns in the demersal fish 

community on the shelf and upper slope regions of the Gulf of Alaska. Fish. Bull. 

100:559-581. 

Keywords: MARINE FISH/ ALASKA/ ABUNDANCE/ STOCK/ 

DISTRIBUTION 

Munday, D.R., G.L. Ennis, D.G. Wright, D.C. Jeffries, E.R. McGreer, and J.S. Mathers. 

1986. Development and evaluation of a model to predict effects of buried 

underwater blasting charges on fish populations in shallow water areas. Can. 

Tech. Rep. Fish. Aquat. Sci. No. 1418. 49 pp. 

Keywords: UNDERWATER EXPLOSIONS/ BLASTING/ FISH/ BRITISH 

COLUMBIA/ MATHEMATICAL MODELS/ BURIED CHARGES 

Musick, J.A. and C.J. Limpus. 1997. Habitat utilization and migration in juvenile sea 

turtles. Pp. 137-164. In: P.L. Lutz and J.A. Musick (eds.). The Biology of Sea 

Turtles. Boca Raton, FL: CRC Press. 432 pp. 

Keywords: MARINE TURTLES/ HABITAT UTILIZATION/ MIGRATION 

Myrberg, A. 1981. Sound communication and interceptions by fishes. Pp. 395-426. In: 

W. Tavolga, R. Fay, and A. Popper (eds.). Hearing and Sound Communication in 

Fishes. New York: Springer-Verlag. 

Keywords: ACOUSTIC BEHAVIOR/ ANATOMY/ BEHAVIOR/ EFFECTS/ 

MARINE FISH 

Myrberg, A.A., Jr. 1982. Using sound to influence the behavior of free-ranging marine 

animals. Pp. 435-469. In: H.E. Winn and B.L. Olla (eds.). Behavior of marine 

animals. New York, NY: Plenum Press. 

Keywords: ACOUSTICS/ BLASTING/ FISH/ IMPACT/ MAMMAL/ MARINE 

MAMMALS/ MARINE/ SOUND/ UNDERWATER 

Myrick, A.C., Jr., E.R. Cassano, and C.W. Oliver. 1990a. Potential for physical injury, 

other than hearing damage, to dolphins from seal bombs used in the yellowfin 

tuna pure-seine fishery: Results from open water tests. U.S. Natl. Mar. Fish. 

Serv., La Jolla, CA. Admin. Rep. LJ-90-07. 28 pp. 

Keywords: BLASTING/ DETERRENT/ DOLPHIN/ FISHERY/ HEARING/ 

INTERACTION/ MARINE MAMMALS/ UNDERWATER 
A-31 

Myrick, A.C., Jr., M. Flink, and C.B. Glick. 1990b. Identification, chemistry and 

behavior of seal bombs used to control dolphins in the yellowfin tuna purse-seine 

fishery in the eastern tropical Pacific. U.S. Natl. Mar. Fish. Serv., La Jolla, CA. 

Admin. Rep. LJ-90-08. 25 pp. 

Keywords: BLASTING/ DETERRENT/ DOLPHIN/ FISHERY/ 

INTERACTION/ MARINE MAMMALS/ PHYSICAL/ UNDERWATER 

Nachtigall, P.E., W.W.L. Au, J.L. Pawloski, and P.W.B. Moore. 1995. Risso’s dolphin 

(Grampus griseus) hearing thresholds in Kaneohe Bay, Hawaii. In: R.A. 

Kastelein, J.A. Thomas, and P.E. Nachtigall (eds.). Sensory systems of aquatic 

mammals. Woerden, Netherlands: De Spil Publishing. 

Keywords: HEARING/ TTS/ DOLPHIN/ AUDITORY BRAINSTEM 

RESPONSE/ MARINE MAMMALS/ NOISE/ IMPACT/ EFFECT/ HAWAII 

Nachtigall, P.E., W.W.L. Au, and J. Pawloski. 1996. Low-frequency hearing in three 

species of odontocetes. J. Acoust. Soc. Am. 100(4, Pt. 2):2,611. 

Keywords: AIR/ EFFECT/ IMPACT/ JETTED/ UNDERWATER/ MARINE 

MAMMALS/ LOW-FREQUENCY/ HEARING/ ODONTOCETES 

Nachtigall, P.E., A. Supin, J.L. Pawloski, and W.W.L. Au. 2001. Measuring recovery 

from temporary threshold shifts with evoked auditory potentials of the bottlenose 

dolphin (Tursiops truncatus). J. Acoust. Soc. Am. 110(5, Pt. 2):2,721. 

Keywords: BOTTLENOSE/ DISTURBANCE/ DOLPHIN / EFFECT/ IMPACT/ 

MARINE MAMMALS/ NOISE/ SOUND/ TTS/ UNDERWATER 

Nachtigall, P.E., J.L. Pawloski, and W.W.L. Au. 2003. Temporary threshold shift and 

recovery following noise exposure in the Atlantic bottlenose dolphin (Tursiops 

truncatus). J. Acoust. Soc. Am. 113(6):3,425-3,429. 

Keywords: BOTTLENOSE / DOLPHIN/ EFFECT/ IMPACT/ NOISE/ 

ODONTOCETES/ TTS/ UNDERWATER 

National Institute for Occupational Safety and Health. 1998. Criteria for a recommended 

standard. U.S. Dept. of Health and Human Services, Centers for Disease Control 

and Prevention, National Institute for Occupational Safety and Health, Cincinnati, 

OH. 105 pp. 

Keywords: AIR/ CRITERIA/ EFFECT/ HUMAN/ IMPACT/ MARINE 

MAMMALS/ NOISE/ TTS/ UNDERWATER 

National Marine Fisheries Service. 1988. Biological Opinion – Consultation for 

Removal of Certain Outer Continental Shelf Oil and Gas Structures in the Gulf of 

Mexico. U.S. Natl. Mar. Fish. Serv., Silver Springs, MD. 25 July 1988. 

Keywords: OIL AND GAS INDUSTRY/ OFFSHORE STRUCTURE 

REMOVAL/ GULF OF MEXICO 
A-32 

National Marine Fisheries Service. 1995a. Small takes of marine mammals incidental to 

specified activities; offshore seismic activities in southern California. 

Fed. Regist. 60:53,753-53,760. 

Keywords: CALIFORNIA/ CRITERIA/ EFFECT/ IMPACT/ LEGISLATION/ 

MARINE MAMMALS/ MITIGATION/ SEAL/ SEISMIC/ WHALE 

National Marine Fisheries Service. 1995b. Incidental take of marine mammals; 

bottlenose dolphins and spotted dolphins/Final Rule. Fed. Regist. 

60:53,139-53,147. 

Keywords: BLASTING/ DEVELOPMENT/ GAS/ GUIDELINE/ GULF OF 

MEXICO/ IMPACT/ MARINE MAMMALS/ OIL/ UNDERWATER 

National Marine Fisheries Service. 1999a. Environmental assessment on testing a pulsed 

power generator to reduce California sea lion depredation of gear and catch 

aboard an actively fishing charter boat off southern California. U.S. Dept. of 

Commerce, National Oceanic and Atmospheric Administration, Natl. Mar. Fish. 

Serv., Long Beach, CA. 85 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ 

PHYSICAL/ SONAR/ UNDERWATER 

National Marine Fisheries Service. 1999b. Record of decision for shock testing the 

SEAWOLF submarine. Fed. Regist. 64(13):3,280-3,286. 

Keywords: BALEEN/ BLASTING/ EFFECT/ IMPACT/ MARINE 

MAMMALS/ NOISE/ ODONTOCETES/ SEAL/ UNDERWATER/ WHALE 

National Marine Fisheries Service. 2000. Small takes of marine mammals incidental to 

specified activities; marine seismic-reflection data collection in southern 

California. Notice of receipt of application, 28 March 2000. Fed. Regist. 

65(60):16,374-16,379. 

Keywords: SEISMIC/ INCIDENTAL TAKE/ MARINE MAMMALS/ NOISE/ 

ODONTOCETES/ PINNIPEDS/ EFFECT 

National Marine Fisheries Service. 2001. Taking and importing marine mammals: 

Taking of marine mammals incidental to naval activities: Final rule 

(Shipshock trial U.S.S. WINSTON S. CHURCHILL (DDG 81). Fed. Regist. 

66(87):22,450-22,467. 

Keywords: BLASTING/ GUIDELINE/ IMPACT/ LAW/ MARINE 

MAMMALS/ NAVY/ UNDERWATER 

National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1991. Recovery 

plan for U.S. population of loggerhead turtle. U.S. Natl. Mar. Fish. Serv., 

Washington, DC. 64 pp. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ NATURAL HISTORY/ CONSERVATION 
A-33 

National Oceanic and Atmospheric Administration. 2002. Report on the workshop on 

acoustic resonance as a source of tissue trauma in cetaceans, 24 and 25 April 

2002, Silver Spring, MD. U.S. Dept. of Commerce, National Oceanic and 

Atmospheric Administration, U.S. Natl. Mar. Fish. Serv. 

Keywords: IMPACT/ MARINE MAMMALS/ NAVY/ SONAR/ STRANDING/ 

WHALE 

National Research Council. 1996. An assessment of techniques for removing offshore 

structures. Committee on Techniques for Removing Fixed Offshore Structures, 

Marine Board, Commission on Engineering and Technical Systems, National 

Research Council. Washington, DC: National Academy Press. 76 pp. 

Keywords: OFFSHORE STRUCTURE REMOVAL/ EXPLOSIVE REMOVAL/ 

ENVIRONMENTAL EFFECTS/ MARINE TURTLES/ BLASTING 

Nedwell, J., K. Needham, A. Turnpenny, and D. Thompson. 1999. Measurement of 

sound during a 3D seismic survey in Blocks 14/14a of the North Sea. Report by 

Subacoustech, Ltd. Hants, U.K. for Texaco Britain PLC, London. Subacoustech 

Ltd. Report Reference 356R0108, February 1999. 54 pp. 

Keywords: MARINE MAMMALS/ SEISMIC/ UNDERWATER/ SOUND/ 

PORPOISE/ AIRGUN/ NORTH SEA 

Nedwell, J., K. Needham, J. Gordon, C. Rogers, and T. Gordon. 2001. The effects of 

underwater blast during wellhead severance in the North Sea. Subacoustech Ltd. 

Report No. 469-R-0202, November 2001. 

Keywords: BURIED CHARGES/ DISTANCE SCALING/ NORTH SEA/ 

OFFSHORE STRUCTURES/ PRESSURE MEASUREMENT/ 

PRESSURE-TIME HISTORIES/ UNDERWATER EXPLOSIONS/ 

WELLHEAD SEVERANCE 

Nedwell, J., K. Needham, J. Gordon, C. Rogers, and T. Gordon. 2002. The effects of 

underwater blast during wellhead severance in the North Sea. Report by 

Subacoustech, Hampshire, U.K. and Ecologic, Fife, U.K. for Coflex Stena 

Offshore Ltd., BP Exploration Oil Co Ltd., Talisman Ltd., Enterprise Oil Ltd., 

and Marathon Oil UK Ltd. www.subacoustech.com. var. pp. 

Keywords: BURIED CHARGES/ DISTANCE SCALING/ NORTH SEA/ 

OFFSHORE STRUCTURES/ PRESSURE MEASUREMENT/ 

PRESSURE-TIME HISTORIES/ UNDERWATER EXPLOSIONS/ 

WELLHEAD SEVERANCE 

Nix, P. and P. Chapman. 1985. Monitoring of underwater blasting operations in False 

Creek, B.C. Pp. 194-210. In: C.D. Greene, F.R. Englehardt, and R.J. Paterson 

(eds.). Effects of explosives in the marine environment. Can. Oil & Gas Lands 

Admin., Environ. Prot. Branch, Ottawa, Ont. Tech. Rep. 5. 

Keywords: ACOUSTICS/ BLASTING/ EXPLOSION EFFECTS/ BRITISH 

COLUMBIA 

Notes: Actual measurements of dead fish in blasting area. Counts of dead fish are 

presented. 
A-34 

Northop, J. and M.F. Morrison. 1971. Underwater sound signals from the Amchitka 

Island underground and underwater explosions. J. Geophys. Res. 

76(8):1,985-1,992. 

Keywords: AMCHITKA ISLAND/ BERING SEA/ BLASTING/ BURIED 

CHARGES/ PRESSURE MEASUREMENT/ PRESSURE-TIME HISTORIES/ 

SPECTRAL LEVELS/ UNDERWATER EXPLOSIONS 

North Pacific Fishery Management Council. 2002. Fishery Management Plan for 

groundfish of the Gulf of Alaska. North Pacific Fishery Management Council, 

Anchorage, AK. 

Keywords: MARINE FISH/ FISHERY MANAGEMENT/ ALASKA 

NSMRL. 1998. Effects of low-frequency water-borne sounds on divers. In: Workshop 

on the Effects of Manmade Sounds on the Marine Environment, 10-12 February 

1998. Office of Naval Research, Bethesda, MD. 19 pp. 

Keywords: BLASTING/ EFFECT/ HUMAN-DIVER/ IMPACT/ 

LOW-FREQUENCY/ MARINE MAMMALS/ NOISE/ SONAR/ SOUND/ 

UNDERWATER 

Officer, C.B. 1958. Introduction to the Theory of Sound Transmission. New York: 

McGraw-Hill. 

Keywords: ACOUSTIC WAVES/ LAYERED MEDIA/ DISTANCE SCALING 

Office of the Surgeon General. 1991. Conventional warfare; ballistic, blast, and burn 

injuries. USA Textbook of Military Medicine; Vol. 5, Pt. 1. 

Keywords: UNDERWATER EXPLOSIVES/ EFFECTS 

O'Keefe, D. 1985. A computer model for predicting the effects of underwater explosions 

on swim bladder fish and marine mammals. Pp. 324-353. In: G.D. Greene, F.R. 

Engelhardt, and R.J. Patterson (eds.). Proceedings of the workshop on effects of 

explosives use in the marine environment, 29-31 January, Halifax. Canada Oil 

and Gas Lands Administration, Environmental Protection Branch, Ottawa, 

Ontario. Tech. Rep. 5. 

Keywords: BLASTING/ EFFECT/ FISH / IMPACT/ MAMMAL/ MARINE 

MAMMALS/ MARINE/ MORTALITY/ SOUND/ UNDERWATER 

O'Keeffe, D.J. and G.A. Young. 1984. Handbook on the environmental effects of 

underwater explosions. Naval Surface Weapons Center, Dahlgren, VA and Silver 

Spring, MD. NSWC TR 83-240. 

Keywords: UNDERWATER EXPLOSIONS/ EFFECTS/ MATHEMATICAL 

MODELS 

Orr, R.T. and R.C. Helm. 1989. Marine mammals of California. California Natural 

History Guides: 29. University of California Press. 

Keywords: MARINE MAMMALS/ CALIFORNIA 
A-35 

Parrott, R. 1991. Seismic and acoustic systems for marine survey used by the Geological 

Survey of Canada: Background information for environmental screening. 

Atlantic Geoscience Centre, Geological Survey of Canada, Bedford Institute of 

Oceanography, Dartmouth, NS. 25 pp. 

Keywords: BLASTING/ EFFECT/ IMPACT/ PHYSICAL/ SEISMIC/ 

UNDERWATER 

Payne, R.S. 1970. Songs of the humpback whale (Catalogue No. ST-620). Capital 

Records, Hollywood, CA. 

Keywords: BALEEN/ CALLS/ HUMPBACK/ MARINE MAMMALS/ SONG/ 

SOUND/ UNDERWATER/ VOCALIZATION/ WHALE 

Payne, R.S. and S. McVay. 1971. Songs of humpback whales. Science 

173(3997):585-597. 

Keywords: BALEEN/ CALLS/ HUMPBACK/ MARINE MAMMALS/ SONG/ 

SOUND/ UNDERWATER/ VOCALIZATION/ WHALE 

Pearson, W., J. Skalski, and C. Malme. 1992. Effects of sounds from a geophysical 

survey device on behavior of captive rockfish. Can. Jour. Fish. Aquat. Sci. 

49:1,343-1,356. 

Keywords: BEHAVIOR/ FISHES/ MARINE FISH/ ROCKFISH/ 

UNDERWATER EXPLOSIONS 

Perrin, W.F., B. Wursig, and J.G.M. Thewissen. 2002. Encyclopedia of Marine 

Mammals. San Diego, CA: Academic Press. 1,414 pp. 

Keywords: MAMMALS/ ABUNDANCE/ BEHAVIOR/ PINNIPED/ DOLPHIN/ 

OTTER/ SURVEY/ ACOUSTICS/ SOUND 

Pet-Soede, C., H.S.J. Cesar, and J.S. Pet. 1999. An economic analysis of blast fishing on 

Indonesian coral reefs. Environ. Cons. 26(2):83-93. 

Keywords: DYNAMITE FISHING/ ENVIRONMENTAL EFFECTS/ HABITAT 

EFFECTS/ MARINE FISH 

Popper, A. and R. Fay. 1999. The auditory periphery in fishes. Pp. 43-100. In: R. Fay 

and A. Popper (eds.). Comparative Hearing: Fish and Amphibians, Springer 

Handbook of Auditory Research. New York: Springer-Verlag. 

Keywords: BEHAVIOR/ HEARING/ AUDITORY BEHAVIOR 

Popper, A. and T. Carlson. 1998. Application of sound and other stimuli to control fish 

behavior. Trans. Am. Fish. Soc. 127:673-707. 

Keywords: ACOUSTIC BEHAVIOR/ ACOUSTICS/ BEHAVIOR/ AUDITORY 

BEHAVIOR/ HEARING 

Popper, A.N. and N.L. Clarke. 1979. Nonsimultaneous auditory masking in the goldfish 

C. auratus. J. Exp. Biol. 83:145-158. 

Keywords: BEHAVIOR/ HEARING/ AUDITORY BEHAVIOR 
A-36 

Powell, A. 1995. Underwater explosion shock wave due to a buried charge. J. Acoust. 

Soc. Am. 98(5, Pt. 2):2,865-2,866. 

Keywords: BLASTING/ BURIED CHARGES/ UNDERWATER 

EXPLOSIONS/ SHOCK WAVES 

Pritchard, P.C.H. 1997. Evolution, phylogeny, and current status. Pp. 1-28. In: P.L. 

Lutz and J.A. Musick (eds.). The Biology of Sea Turtles. Boca Raton, FL: CRC 

Press. 

Keywords: MARINE TURTLES/ EVOLUTION/ PHYLOGENY/ CURRENT 

STATUS 

Putt, R.E., Jr. 1982. A quantitative study of fish populations associated with a platform 

within Bucaneer oil field, northwestern Gulf of Mexico. M.S. Thesis, Texas 

A&M University, College Station, TX. 

Keywords: GULF OF MEXICO/ MARINE FISH/ OFFSHORE OIL AND GAS/ 

OIL AND GAS INDUSTRY 

Reidenberg, J.S. and J.T. Laitman. 2003. Appearance of odontocete respiratory tissues 

after exposure to blast parameters. p. 30. In: R. Gisner (ed.). Environmental 

consequences of underwater sound, 12-16 May 2003. Office of Naval Research, 

Life Sciences Research Office, Bethesda, MD. 

Keywords: BLASTING/ DAMAGE/ EFFECT/ IMPACT/ LABORATORY/ 

MARINE MAMMALS/ NOISE/ ODONTOCETES/ UNDERWATER 

Reiter, G.A. 1981. Cold weather response F/V Ryuko Maru No. 2, St. Paul, Pribiloff 

Islands, Alaska. Pp. 227-231. In: Proceedings 1981 Oil Spill Conference. 

American Petroleum Institute, Washington, DC. API Publ. 4334. 

Keywords: ALASKA/ BLASTING/ EFFECT/ FUR/ IMPACT/ MARINE 

MAMMALS/ OIL/ PINNIPED/ SEAL/ SHIPPING/ SPILL 

Rice, D.W. 1998. Marine Mammals of the World - Systematics and Distribution. The 

Society for Marine Mammalogy. Special Publication Number 4. 231 pp. 

Keywords: MARINE MAMMALS/ DISTRIBUTION 

Richardson, G.E. 1989. Sea turtles and structure removals in the Gulf of Mexico. 

Pp. 145-146. In: S.A. Eckert, K.L. Eckert, and T.H. Richardson (comps.). 

Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and 

Biology, 7-11 February, 1989, Jekyll Island, GA. NOAA Tech. Memo. 

NMFS-SEFC-232. 306 pp. 

Keywords: SEA TURTLES/ EXPLOSIVES/ LEGAL REQUIREMENTS/ 

MITIGATION REQUIREMENTS 
A-37 

Richardson, G.E. and K.L. Graham. 1987. Structure removal activities Central and 

Western Gulf of Mexico Planning Areas - Programmatic environmental 

assessment. Prepared for the U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico Outer Continental Shelf Regional Office. OCS EIS/EA 

MMS 87-0002. 47 pp. + apps. 

Keywords: ALABAMA/ ENVIRONMENTAL ASSESSMENT/ GULF OF 

MEXICO/ LOUISIANA/ MISSISSIPPI/ OIL/ STRUCTURE REMOVAL/ 

TEXAS 

Richardson, W.J. and B. Wursig. 1997. Influences of man-made noise and other human 

actions on cetacean behaviour. Marine and Freshwater Behaviour and Physiology 

29:183-209. 

Keywords: AIRCRAFT/ BLASTING/ DEVELOPMENT/ DRILLING/ 

ECHOSOUNDER/ EFFECT/ EXPLORATION/ IMPACT/ MARINE 

MAMMALS/ NOISE/ OIL/ SEISMIC/ SHIPPING/ SOUND/ UNDERWATER/ 

WHALE 

Richardson, W.J. and C.I. Malme. 1997. Point Mugu Sea Range EIS/ OEIS: Proposed 

noise criteria for marine mammals. Report by LGL Limited, King City, ON for 

Southwest Division, Naval Facilities Engineering Command, San Diego, CA. 13 

pp. 

Keywords: BLASTING/ CRITERIA/ DISTURBANCE/ IMPACT/ MARINE 

MAMMALS/ SEISMIC 

Richardson, W.J., B. Würsig, and C.R. Greene. 1986. Reactions of bowhead whales, 

Balaena mysticetus, to seismic exploration in the Canadian Beaufort Sea. 

J. Acoust. Soc. Am. 79:1,117-1,128. 

Keywords: ACOUSTICS/ BEAUFORT SEA/ BOWHEAD/ DISTURBANCE/ 

MARINE MAMMALS/ SEISMIC/ SOUND/ UNDERWATER 

Richardson, W.J., D.H. Thomson, D.W. Owens, and R.L. Tremaine. 1993. Assessment 

of potential impacts of small explosions in the New York Bight on marine 

animals and fisheries. Report by LGL Limited, Toronto for BBN Systems and 

Technologies, Cambridge, MA. 95 pp. 

Keywords: BIRDS/ BLASTING/ EFFECT/ FISH/ FISHERY/ IMPACT/ 

MAMMAL/ MARINE MAMMALS/ MARINE/ SOUND/ UNDERWATER 

Richardson, W.J., C.R. Greene, J.P. Hickie, R.A. Davis, and D.H. Thomson. 1989. 

Effects of offshore petroleum operations on cold water marine mammals: A 

literature review. 2nd edition. American Petroleum Institute, Washington, DC. 

385 pp. 

Keywords: ARCTIC/ BEAR/ BLASTING/ EFFECT/ EXPLORATION/ GAS/ 

IMPACT/ MAMMAL/ MARINE MAMMALS/ MARINE/ OIL/ POLAR/ 

POLAR BEAR/ PRODUCTION/ SEAL/ SOUND/ UNDERWATER/ WHALE 
A-38 

Richardson, W.J., S. Davis, R. Harris, D.W. Owens, N.J. Patenaude, D.H. Thomson, R.C. 

Atkinson, and W.J. Marshall. 1995a. Assessment of potential impacts of small 

explosions in the Korea Strait on marine animals and fisheries. Report by LGL 

Limited and BBN Systems and Technologies, Cambridge, MA for Maritime 

Systems Technology Office, Advanced Projects Research Agency. 128 pp. 

Keywords: BIRDS/ BLASTING/ EFFECT/ FISH/ FISHERY/ IMPACT/ 

MAMMAL/ MARINE MAMMALS/ MARINE/ SOUND/ UNDERWATER 

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. 1995b. Marine 

Mammals and Noise. San Diego: Academic Press. 576 pp. 

Keywords: BLASTING/ DEVELOPMENT/ DISTURBANCE/ EFFECT/ 

EXPLORATION/ GAS/ IMPACT/ MAMMAL/ MARINE MAMMALS/ 

MARINE/ OIL/ SEISMIC/ SHIPPING/ SONAR/ SOUND/ UNDERWATER/ 

VOCALIZATION 

Richardson, W.J., G.W. Miller, and C.R. Greene, Jr. 1999. Displacement of migrating 

bowhead whales by sounds from seismic surveys in shallow waters of the 

Beaufort Sea. J. Acoust. Soc. Am. 106(4, Pt. 2):2,281. 

Keywords: BEAUFORT SEA/ BOWHEAD/ DISTURBANCE/ BALEEN/ 

MARINE MAMMALS/ IMPACT/ EFFECTS/ SEISMIC/ UNDERWATER/ 

CANADA 

Richmond, D.R., J.T. Yelverton, and E.R. Fletcher. 1973. Far-field underwater blast 

injuries produced by small charges. Lovelace Foundation, Albuquerque, NM. 

Rep. No. DNA 3081T. 

Keywords: BLASTING/ IMPACT/ UNDERWATER EXPLOSIONS/ EFFECTS 

Ridgway, S.H. 1995. Marine mammal science and U.S. Navy ship shock trials. Mar. 

Mamm. Sci. 11(4):590-593. 

Keywords: BLASTING/ CALIFORNIA/ IMPACT/ MARINE MAMMALS/ 

NAVY/ PACIFIC/ SEAL/ UNDERWATER/ WHALE 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J.H. Anderson. 1969. 

Hearing in the giant sea turtle, Chelonia mydas. Proc. Natl. Acad. Sci. 

64:884-890. 

Keywords: MARINE TURTLES/ GREEN TURTLE/ CHELONIA MYDAS/ 

ACOUSTICS 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J. Anderson. 1970. 

Sensitivity of the green sea turtle's ear as shown by its electrical potentials. 

J. Acoust. Soc. Am. 47:67. 

Keywords: MARINE TURTLES/ ACOUSTICS/ HEARING/ 

BONE-CONDUCTED HEARING 
A-39 

Ridgway, S.H., D.A. Carder, R.R. Smith, T. Kamolnick, C.E. Schlundt, and W.R. 

Elseberry. 1997. Behavioral responses and temporary shift in masked hearing 

threshold of bottlenose dolphins, Tursiops truncatus, to 1-second tones of 141 to 

201 dB re 1 micro-Pa. Naval Command, Control and Ocean Surveillance Center, 

RDT&E Division, San Diego, CA. Tech. Rep. 1751. 16 pp. 

Keywords: CRITERIA/ DAMAGE/ DOLPHIN/ HEARING/ IMPACT/ 

BOTTLENOSE 

Riedman, M. 1990. The Pinnipeds - Seals, Sea Lions, and Walruses. University of 

California Press. 439 pp. 

Keywords: SEAL/ SEA LION/ WALRUS/ MARINE MAMMALS/ PINNIPED 

Rogers, P.H. 1977. Weak-shock solution for underwater explosive shock waves. J. 

Acoust. Soc. Am. 62(6):1,412-1,419. 

Keywords: EXPLOSION PHYSICS/ SHOCK WAVES/ UNDERWATER 

EXPLOSIONS 

Ronquillo, I.A. 1950. Anatomical evidence in cases of fish killed by explosives. Bull. 

Fish. Soc. Philip. 1:52-56. 

Keywords: EFFECTS/ FISH-KILL/ DYNAMITE FISHING/ MORTALITY 

CAUSE/ PHILIPPINES 

Rooker, J.R., Q.R. Dokken, C.V. Pattengill, and G.J. Holt. 1997. Fish assemblages on 

artificial and natural reefs in the Flower Gardens Bank National Marine 

Sanctuary. Coral Reefs 16:83-92. 

Keywords: MARINE FISH/ OFFSHORE STRUCTURES/ OFFSHORE OIL 

AND GAS 

Rosman, I., G.S. Boland, L. Martin, and C. Chandler. 1987. Underwater sightings of sea 

turtles in the northern Gulf of Mexico. U.S. Dept. of the Interior, Minerals 

Management Service. OCS Study MMS 87-0107. 37 pp. 

Keywords: MARINE FISH/ OFFSHORE STRUCTURES/ OFFSHORE OIL 

AND GAS 

Ruckdeschel, C., C.R. Shoop, and G.R. Zug. 2000. Sea turtles of the Georgia coast. 

Occasional Publications of the Cumberland Island Museum, Number 1. 100 pp. 

Keywords: MARINE TURTLES/ NATURAL HISTORY 

Rugh, D.J., B.A. Mahoney, C.L. Sims, B.K. Smith, and R.C. Hobbs. 2003. Aerial 

surveys of belugas in Cook Inlet, Alaska, June 2003. Report prepared by National 

Marine Mammals Laboratory, Seattle, WA, and U.S. Natl. Mar. Fish. Serv., 

Alaska Regional Office, Anchorage, AK. 17 pp. 

Keywords: BELUGA/ MARINE MAMMALS/ ALASKA/ SURVEY 
A-40 

Russell, B.C., F.H. Talbot, G.R.V. Anderson, and B. Goldman. 1978. Collection and 

sampling of reef fishes. Pp. 329-345. In: D.R. Stoddart and R.E. Johannes (eds.). 

Coral Reefs: Research Methods. Monographs on Oceanographic Methodology 5. 

Paris, France: UNESCO. 

Keywords: DYNAMITE FISHING/ MARINE FISH/ UNDERWATER 

EXPLOSIVES/ SAMPLING 

Saila, S.B., V.L.J. Kocic, and J.W. McManus. 1993. Modelling the effects of destructive 

fishing practices on tropical coral reefs. Mar. Ecol. Prog. Ser. 94:51-60. 

Keywords: DYNAMITE FISHING/ ENVIRONMENTAL EFFECTS/ LETHAL 

RANGES/ MATHEMATICAL MODELS 

Sakaguchi, S., O. Fukuhara, S. Umezawa, M. Fujiya, and T. Ogawa. 1976. The 

influence of underwater explosion on fishes. Bull. Nansei. Reg. Fish. Res. Lab. 

9:33-65. 

Keywords: BEHAVIOR/ CAGING EXPERIMENTS/ EFFECTS/ FISH-KILL/ 

FISHES/ MATHEMATICAL MODELS/ MORTALITY CAUSE 

Schlundt, C.E., J.J. Finneran, D.A. Carder, and S.H. Ridgway. 2000. Temporary shift in 

masked hearing thresholds of bottlenose dolphins, Tursiops truncatus, and white 

whales, Delphinapterus leucas after exposure to intense tones. J. Acoust. Soc. 

Am. 107(6):3,496-3,508. 

Keywords: BELUGA/ DOLPHIN/ EFFECT/ HEARING/ IMPACT/ MARINE 

MAMMALS/ NOISE/ TTS/ UNDERWATER 

Scholik, A.R. and H.Y. Yan. 2001. The effects of underwater noise on auditory 

sensitivity of fish. Proc. I.O.A. 23(4):27-36. 

Keywords: ACOUSTIC BEHAVIOR/ AUDITORY BEHAVIOR/ BEHAVIOR/ 

FISHES 

Schwartz, S. 1990. Environmental assessment ship hardening program sea test range, 

Pacific Missile Test Center, Ventura County, CA. Environmental Division, Naval 

Air Station, Point Mugu, CA. 25 pp. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ NAVY/ 

SHIPPING/ UNDERWATER/ WHALE 

Settle, L.R., J.J. Govoni, M.D. Greene, and M.A. West. 2002. Investigation of impacts 

of underwater explosions on larval and early juvenile fishes. Part 1: The effects 

of underwater explosions on larval fish with implications for the Wilmington 

Harbor Project. Report to U.S. Army Corps of Engineers, Wilmington District, 

Wilmington, NC. 64 pp. 

Keywords: ENVIRONMENTAL EFFECTS/ FISHES/ LARVAL FISH/ 

MATHEMATICAL MODELS/ NORTH CAROLINA/ ORGAN TRAUMA 
A-41 

Sigurdson, J.E., J.B. Gaspin, and D.A. Helwig. 2001. Criteria for marine mammal 

auditory threshold shift: Appendix E, Final environmental impact statement: 

Shock trial of the WINSTON S. CHURCHILL (DDG 81). Space and Naval 

Warfare Systems Center, San Diego, CA. 35 pp. 

Keywords: BALEEN/ BLASTING/ EFFECT/ EIS/ HEARING/ IMPACT/ 

MAMMAL/ MARINE MAMMALS/ NAVY/ ODONTOCETES/ TTS/ 

UNDERWATER/ WHALE 

Silbiger, H.R. 1965. Temporary threshold shift due to single clicks. J. Acoust. Soc. Am. 

38(5):937-938. 

Keywords: BLASTING/ MARINE MAMMALS/ TTS 

Skalski, J., W. Pearson, and C. Malme. 1992. Effects of sounds from a geophysical 

survey device on catch per unit effort on a hook-and-line fishery for rockfish 

(Sebastes spp.). Can. Jour. Fish. Aquat. Sci. 49:1,357-1,365. 

Keywords: BEHAVIOR/ MARINE FISH/ ROCKFISH/ UNDERWATER 

EXPLOSIONS 

Sonnier, F., J. Teerling, and H.D. Hoese. 1976. Observations on the offshore reef and 

platform fish fauna of Louisiana. Copeia 1:105-111. 

Keywords: GULF OF MEXICO/ HABITAT UTILIZATION/ MARINE FISH/ 

OFFSHORE STRUCTURES/ OFFSHORE OIL AND GAS 

Stanley, D.R. and C.A. Wilson. 1990. A fishery-dependent based study of fish species 

composition and associated catch rates around oil and gas structures off 

Louisiana. Fish. Bull. 88(4):719-730. 

Keywords: FISHES/ GULF OF MEXICO/ HABITAT UTILIZATION/ 

MARINE FISH/ OFFSHORE STRUCTURES/ OIL AND GAS INDUSTRY 

Stanley, D.R. and C.A. Wilson. 1996. Seasonal and spatial variation in abundance and 

size distribution of fishes associated with a petroleum platform in the northern 

Gulf of Mexico. Can. Jour. Fish. Aquat. Sci. 54:1,166-1,177. 

Keywords: FISHES/ GULF OF MEXICO/ LOUISIANA/ OFFSHORE 

STRUCTURES/ OIL AND GAS INDUSTRY/ HABITAT UTILIZATION 

Stanley, D.R. and C.A. Wilson. 1998. Spatial variation in fish density at three petroleum 

platforms as measured with dual-beam hydroacoustics. Gulf of Mexico Science 

16(1):73-82. 

Keywords: FISHES/ GULF OF MEXICO/ LOUISIANA/ OFFSHORE 

STRUCTURES/ OIL AND GAS INDUSTRY/ HABITAT UTILIZATION 

Stanley, D.R. and C.A. Wilson. 2000. Variation in the density and species composition 

of fishes associated with three petroleum platforms using dual beam 

hydroacoustics. Fisheries 47:161-172. 

Keywords: MARINE FISH/ OFFSHORE STRUCTURES/ GULF OF MEXICO/ 

HABITAT UTILIZATION 
A-42 

Stanley, D.R. and C.A. Wilson. 2002. Seasonal and spatial variation in the biomass and 

size frequency distribution of fish associated with oil and gas platforms in the 

northern Gulf of Mexico. Pp. 421-471. In: M. McKay, J. Nides, and D. Vigil 

(eds.). Proceedings: Gulf of Mexico fish and fisheries: Bringing together new and 

recent research, October 2000. U.S. Dept. of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 

2002-004. 674 pp. 

Keywords: FISHES/ GULF OF MEXICO/ LOUISIANA/ OFFSHORE 

STRUCTURES/ OIL AND GAS INDUSTRY/ HABITAT UTILIZATION 

Stobutzki, I.C. and D.R. Bellwood. 1998. Nocturnal orientation to reefs by late pelagic 

stage coral reef fishes. Coral Reefs 17:103-110. 

Keywords: MARINE FISH/ ACOUSTICS/ LARVAL FISH 

Stone, C.J. 2003. The effects of seismic activity on marine mammals in UK waters, 

1998-2000. Aberdeen, UK: JNCC Report No. 323. 78 pp. 

Keywords: NOISE/ SURVEYS/ UNDERWATER/ MARINE MAMMALS/ 

SEISMIC/ SOUND/ IMPACT/ EFFECTS/ UNITED KINGDOM 

Stoneburner, D.L. 1982. Satellite telemetry of loggerhead sea turtle movement in the 

Georgia Bight. Copeia 2:400-408. 

Keywords: MARINE TURTLES/ LOGGERHEAD TURTLE/ CARETTA 

CARETTA/ GEORGIA 

Sverdrup, A., E. Kjellsby, P.G. Kruger, R. Floysand, F.R. Knudsen, P.S. Enger, 

G. Serck-Hanssen, and K.B. Helle. 1994. Effects of experimental seismic shock 

on vasoactivity of arteries, integrity of the vascular endothelium and on primary 

stress hormones of the Atlantic salmon. Journal of Fish Biology 45:973-995. 

Keywords: EFFECTS/ ANATOMY/ SUB-LETHAL/ PHYSIOLOGY 

Szymanski, M.D., D.E. Bain, K. Kiehl, S. Pennington, S. Wong, and K.R. Henry. 1999. 

Killer whale (Orcinus orca) hearing: Auditory brainstem response and behavioral 

audiograms. J. Acoust. Soc. Am. 106(2):1,134-1,141. 

Keywords: HEARING/ NOISE/ MARINE MAMMALS/ KILLER/ 

ACOUSTICS/ AUDITORY BRAINSTEM RESPONSE 

Teleki, G.C. and A.J. Chamberlain. 1978. Acute effects of underwater construction 

blasting on fishes in Long Point Bay, Lake Erie. J. Fish. Res. Board Can. 

35:1,191-1,198. 

Keywords: EFFECTS/ CANADA/ CAGING EXPERIMENTS/ BLASTING/ 

SWIMBLADDER FISH/ FISHES/ UNDERWATER EXPLOSIVES 

Thomson, J.A. 1958. Biological effects of the Ripple Rock explosion. Progress Reports 

of the Pacific Coast Stations, Biological Station, Nanaimo, BC. 8 pp. 

Keywords: BLASTING/ EFFECT/ FISH/ IMPACT/ INVERTEBRATE/ 

MARINE MAMMALS 
A-43 

Todd, S., P. Stevick, J. Lien, F. Marques, and D. Ketten. 1996. Behavioral effects of 

exposure to underwater explosions in humpback whales Megaptera novaeangliae. 

Canadian Journal of Zoology 74:1,661-1,672. 

Keywords: BLASTING/ EFFECT/ HUMPBACK/ IMPACT/ MARINE 

MAMMALS/ SEISMIC/ SOUND/ UNDERWATER/ WHALE 

Tolimieri, N., A. Jeffs, and J. Montgomery. 2000. Ambient sound as a cue for 

navigation by the pelagic larvae of reef fishes. Mar. Ecol. Prog. Ser. 

207:219-224. 

Keywords: MARINE FISH/ ACOUSTICS/ LARVAL FISH 

Tonndorf, J. 1972. Bone conduction. Pp. 197-237. In: J.V. Tobias (ed.). Foundations 

of Modern Auditory Theory, Vol. II. New York: Academic Press. 

Keywords: ACOUSTICS/ BONE CONDUCTED HEARING 

Trasky, L.L. 1976. Environmental impact of seismic exploration and blasting in the 

aquatic environment. Unpublished Report Alaska Department of Fish and Game, 

Anchorage AK. p. 23. 

Keywords: BLASTING/ EFFECT / FISH/ IMPACT/ JETTED/ MARINE/ 

SEISMIC/ SOUND/ UNDERWATER 

Traxler, S.L., B.R. Murphy, and T.L. Linton. 1990. Subsediment seismic explosions do 

not injure caged fish in a freshwater reservoir. J. Freshwater Ecol. 8(1):73. 

Keywords: BURIED CHARGES/ UNDERWATER EXPLOSIONS/ TEXAS/ 

FISHES 

Tremel, D.P., J.A. Thomas, K.T. Ramirez, G.S. Dye, W.A. Bachman, A.N. Orban, and 

K.K. Grimm. 1998. Underwater hearing sensitivity of a Pacific white-sided 

dolphin, Lagenorhynchus obliquidens. Aquat. Mamm. 24(2):63-69. 

Keywords: DOLPHIN/ MARINE MAMMALS/ HEARING/ SOUND/ 

UNDERWATER 

Urick, R.J. 1975. Principles of Underwater Sound. 3rd ed. New York: McGraw-Hill. 

423 pp. 

Keywords: BLASTING/ ACOUSTIC WAVES/ BUBBLE PULSE / DISTANCE 

SCALING/ SHOCK WAVES/ UNDERWATER ACOUSTICS 

U.S. Air Force. 1997. Final environmental information in support of a request for a 

letter of authorization for the incidental take of marine mammals for 

programmatic operations at Vandenberg AFB, California. U.S. Air Force, 30th 

Space Wing, Vandenberg, AFB, California for National Marine Fisheries Service, 

Office of Protected Resources, Silver Spring, MD. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ MISSILE/ NAVY/ 

NOISE/ UNDERWATER 
A-44 

U.S. Air Force. 1998. Final environmental assessment for coastal testing of the Shallow 

Water Assault Breaching (SABRE) and Distributed Explosive Technology (DET) 

systems at Eglin Air Force Base, Florida (RCS 96-424 and RCS 98-263). Report 

by QST Environmental Inc., Gainesville, Florida for Department of the Air Force, 

Eglin Air Force Base, Gainesville, FL. 

Keywords: ABUNDANCE/ BLASTING/ DENSITY/ EFFECT/ GULF OF 

MEXICO/ IMPACT/ MARINE MAMMALS/ SEA TURTLE/ TTS/ 

UNDERWATER 

U.S. Navy. 1998. Final environmental impact statement: Shock testing the SEAWOLF 

submarine. Department of the Navy, Southern Division, Naval Facilities 

Engineering Command, North Charleston, SC. 

Keywords: BIRDS/ BLASTING/ DENSITY/ EFFECT/ EIS/ FISH/ IMPACT/ 

MARINE MAMMALS/ MARINE/ SEA TURTLE/ TURTLE 

U.S. Navy. 1999a. Draft environmental impact statement: Shock trial of the WINSTON 

S. CHURCHILL (DDG81). Department of the Navy, Washington, DC. 

Keywords: ATLANTIC/ BLASTING/ COAST/ DENSITY/ EAST/ EFFECT / 

EIS/ FISH/ IMPACT/ MARINE MAMMALS/ MODEL/ SEA-TURTLE/ 

UNDERWATER/ WHALE 

U.S. Navy. 1999b. Draft overseas environmental impact statement/ Environmental 

impact statement/East coast shallow water training range. TAMS Consultants 

Inc, New York, NY. 

Keywords: BALEEN/ BLASTING/ EFFECT/ EIS/ FISH/ HEARING/ IMPACT/ 

MAMMAL/ MARINE MAMMALS/ NAVY/ ODONTOCETES/ TTS/ TURTLE/ 

UNDERWATER/ WHALE 

U.S. Navy. 2000a. Biological assessment for sinking exercises (Sinkex) [Atlantic Fleet]. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ NAVY/ NOISE/ 

UNDERWATER 

U.S. Navy. 2000b. Environmental monitoring report for distributed explosive 

technology operational assessment at Horse Beach Cove, San Clemente Island, 

31 October 2000. Naval Surface Warfare Center, Program Executive Officer for 

Mine Warfare (PMS407), Washington, DC. 14 pp. 

Keywords: BLASTING/ EFFECT/ FISH/ IMPACT/ MARINE MAMMALS/ 

MONITORING/ NAVY/ PHYSICAL/ UNDERWATER 

Verboom, W.C. 2000. Intense sound levels and marine mammals: Impacts on cetaceans. 

TNO-TPD Rep., Delft, The Netherlands. HAG-RPT-000037. 84 pp. 

Keywords: MARINE MAMMALS/ SOUND/ ACOUSTICS/ IMPACT/ 

EFFECTS/ UNDERWATER 

Ward, W.D. 1960. Recovery from high values of temporary threshold shift. J. Acoust. 

Soc. Am. 32(4):497-500. 

Keywords: AIR/ EFFECT/ IMPACT/ MARINE MAMMALS/ TTS 
A-45 

Ward, W.D. 1962. Effect of temporal spacing on temporary threshold shift from 

impulses. J. Acoust. Soc. Am. 34(9):1,230-1,232. 

Keywords: AIR/ EFFECT/ IMPACT/ MARINE MAMMALS/ TTS 

Ward, W.D. 1970. Temporary threshold shift and damage risk criteria for intermittent 

noise exposures. J. Acoust. Soc. Am. 48(2, Pt. 2):561-574. 

Keywords: AIR/ EFFECT/ IMPACT/ MARINE MAMMALS/ TTS 

Ward, W.D. 1991. The role of intermittence in PTS. J. Acoust. Soc. Am. 

90(1):164-169. 

Keywords: AIR/ EFFECT/ IMPACT/ MARINE MAMMALS/ PTS/ TTS 

Ward, W.D. 1997. Effects of high-intensity sound. Pp. 1,497-1,507. In: M.J. Crocker 

(ed.). Encyclopedia of Acoustics. New York: J. Wiley & Sons. 

Keywords: AIR / EFFECT/ IMPACT/ MARINE MAMMALS/ NOISE/ TTS 

Ward, W.D., W. Selters, and A. Glorig. 1961. Exploratory studies on temporary 

threshold shift from impulses. J. Acoust. Soc. Am. 33(6):781-793. 

Keywords: AIR/ EFFECT/ IMPACT/ MARINE MAMMALS/ TTS 

Waring, G.T., J.M. Quintal, and S.L. Swartz (eds.). 2001. U.S. Atlantic and Gulf of 

Mexico Marine Mammal Stock Assessments – 2001. NOAA Tech. Memo. 

NMFS-NE-168. 307 pp. 

Keywords: DISTRIBUTION/ MARINE MAMMALS/ ATLANTIC OCEAN/ 

GULF OF MEXICO/ ABUNDANCE 

Waring, G.T., J.M. Quintal, and C.P. Fairfield (eds.). 2002. Draft U.S. Atlantic and Gulf 

of Mexico Marine Mammal Stock Assessments – 2002. NOAA Tech. Memo. 

NFMS-NE-169. 183 pp. 

Keywords: DISTRIBUTION/ MARINE MAMMALS/ ATLANTIC OCEAN/ 

GULF OF MEXICO/ ABUNDANCE 

Watkins, W.A. 1986. Whale reactions to human activities in Cape Cod waters. Mar. 

Mamm. Sci. 2(4):251-262. 

Keywords: DISTURBANCE/ SHIPPING/ SONAR/ MARINE MAMMALS/ 

WHALE/ IMPACT/ EFFECT/ UNDERWATER/ SOUND 

Wever, E.G. 1978. The Reptile Ear. Its Structure and Function. Princeton, NJ: 

Princeton University Press. 

Keywords: MARINE TURTLES/ EAR/ ANATOMY 

Whitehead, H. and L. Weilgart. 1995. Marine mammal science, the U.S. Navy and 

academic freedom. Mar. Mamm. Sci. 11(2):260-263. 

Keywords: BLASTING/ IMPACT/ MARINE MAMMALS/ NAVY/ SEAL/ 

UNDERWATER/ WHALE 
A-46 

Wiley, M.L., J.B. Gaspin, and J.F. Goertner. 1981. Effects of underwater explosions on 

fish with a dynamical model to predict fishkill. Ocean Science and Engineering 

6:223-284. 

Keywords: EFFECTS/ EXPLOSION EFFECTS/ FISHES/ MARINE FISH/ 

PRESSURE EFFECTS/ UNDERWATER EXPLOSIONS/ SWIMBLADDER 

FISH/ MATHEMATICAL MODELS 

Williams, D.M. and A.I. Hatcher. 1983. Structure of fish communities on outer slopes of 

inshore, mid-shelf, and outer shelf reefs of the Great Barrier Reef. Mar. Ecol. 

Prog. Ser. 10:239-250. 

Keywords: MARINE FISH/ SAMPLING/ DYNAMITE FISHING 

Wilson, C.A. and D.L. Nieland. 2001. Age and growth of red snapper from the northern 

Gulf of Mexico off Louisiana. Fish. Bull. 99(4):653-664. 

Keywords: GULF OF MEXICO/ OFFSHORE PLATFORMS/ RED SNAPPER 

Witzell, W.N. 1982. Observations of the green sea turtle (Chelonia mydas) in Western 

Samoa. Copeia 1:183-185. 

Keywords: MARINE TURTLES/ GREEN TURTLE/ CHELONIA MYDAS/ 

SAMOA 

Wright, D.G. 1982. A discussion paper on the effects of explosives on fish and marine 

mammals in the waters of the Northwest Territories. Can. Tech. Rep. Fish. 

Aquat. Sci. 1052:1-16. 

Keywords: EXPLOSIVES/ MARINE FISH/ MARINE MAMMALS/ CANADA/ 

NORTHWEST TERRITORIES/ BLASTING 

Wright, D.G. and G.E. Hopky. 1998. Guidelines for the use of explosives in or near 

Canadian fisheries waters. Can. Tech. Rep. Fish. Aquat. Sci. 2107:1-34. 

Keywords: BURIED CHARGES/ CANADA/ ENVIRONMENTAL IMPACT/ 

ENVIRONMENTAL MANAGEMENT/ FISH MORTALITY/ UNDERWATER 

EXPLOSIONS/ BLASTING 

Wright, R.A. and W.H. Allton. 1971. Sea otter studies in the vicinity of Amchitka 

Island. Bioscience 21:673-677. 

Keywords: BLASTING/ EFFECT/ IMPACT/ MARINE MAMMALS/ OTTER/ 

SEA/ SEISMIC 

Würsig, B., T.A. Jefferson, and D.J. Schmidly. 2000. The Marine Mammals of the Gulf 

of Mexico. College Station, TX: Texas A&M University Press. 232 pp. 

Keywords: DISTRIBUTION/ MARINE MAMMALS/ GULF OF MEXICO/ 

ABUNDANCE 

Wyneken, J. 1997. Sea turtle locomotion: Mechanics, behavior, and energetics. 

Pp. 165-198. In: P.L. Lutz and J.A. Musick (eds.). The Biology of Sea Turtles. 

Boca Raton, FL: CRC Press. 

Keywords: MARINE TURTLES/ LOCOMOTION 
A-47 

Wynne, K. 1992. Guide to marine mammals of Alaska. Alaska Sea Grant College 

Program, Fairbanks, AK. 75 pp. 

Keywords: MARINE MAMMALS/ ALASKA 

Yan, H.Y., M.L. Fine, N.S. Horn, and W.E. Colon. 2000. Variability in the role of the 

gasbladder in fish audition. J. Comp. Physiol. A. 186:435-445. 

Keywords: AUDITORY BEHAVIOR/ ANATOMY/ ACOUSTICS/ FISHES/ 

SWIMBLADDER 

Yelverton, J.T. 1981. Underwater explosion damage risk criteria for fish, birds, and 

mammals. Paper presented at the 102nd meeting of the Acoustical Society of 

America, Carillon Hotel, 30 November - 4 December 1981 (Abstract J. Acoust. 

Soc. Am. Suppl. 1, Vol. 70, Fall 1981), Miami Beach, FL. 19 pp. 

Keywords: BIRDS/ BLASTING/ FISH/ IMPACT/ MAMMAL/ MARINE 

MAMMALS/ MARINE/ SOUND/ UNDERWATER 

Yelverton, J.T., D.R. Richmond, E.R. Fletcher, and R.K. Jones. 1973. Safe distances 

from underwater explosions for mammals and birds. Report by Lovelace 

Foundation for Medical Education and Research, Albuquerque, NM for Defense 

Nuclear Agency, Washington, DC. DNA 3114T. 67 pp. 

Keywords: UNDERWATER EXPLOSIONS/ BLASTING/ MARINE 

MAMMALS/ BIRDS 

Yelverton, J.T., D.R. Richmond, W. Hicks, K. Saunders, and E.R. Fletcher. 1975. The 

relationships between fish size and their response to underwater blast. Defense 

Nuclear Agency, Topical Report DNA 3677T. 

Keywords: MATHEMATICAL MODELS/ EXPLOSION EFFECTS/ 

MORTALITY CAUSE/ PRESSURE EFFECTS/ SHOCK WAVES/ 

SWIMBLADDER FISH/ UNDERWATER EXPLOSIONS 

Young, G.A. 1973. Guidelines for evaluating the environmental effects of underwater 

explosion tests. Naval Ordnance Laboratory, White Oak Laboratory, Silver 

Spring, MD. NOL-TR 72-211. 

Keywords: ENVIRONMENTAL IMPACT/ ENVIRONMENTAL 

MANAGEMENT/ UNDERWATER EXPLOSIONS 

Young, G.A. 1991. Concise methods of predicting the effects of underwater explosions 

on marine life. Naval Surface Weapons Center, Silver Spring, MD. 

NAVSWC-MP-91-220. 22 pp. 

Keywords: UNDERWATER EXPLOSIONS/ BLASTING/ MARINE 

MAMMALS/ BIRDS 

Zelick, R., D. Mann, and A. Popper. 1999. Acoustic communication in fishes and frogs. 

Pp. 363-412. In: R. Fay and A. Popper (eds.). Comparative Hearing: Fish and 

Amphibians. Springer Handbook of Auditory Research. New York: 

Springer-Verlag. 

Keywords: ACOUSTIC BEHAVIOR/ BEHAVIOR/ HEARING/ FISHES 
A-48 

Zhou, K. and Z. Xingduan. 1991. Baiji/The Yangtze River Dolphin and Other 

Endangered Animals of China. Washington, DC and Nanjing, China: Stone Wall 

Press and Yilin Press. 129 pp. 

Keywords: BLASTING/ DOLPHIN/ IMPACT/ MARINE MAMMALS/ RIVER/ 

UNDERWATER 
The Department of the Interior Mission

As the Nation's principal conservation agency, the Department of the Interior has responsibility 

for most of our nationally owned public lands and natural resources. This includes fostering 

sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; 

preserving the environmental and cultural values of our national parks and historical places; 

and providing for the enjoyment of life through outdoor recreation. The Department assesses 

our energy and mineral resources and works to ensure that their development is in the best 

interests of all our people by encouraging stewardship and citizen participation in their care. 

The Department also has a major responsibility for American Indian reservation communities 

and for people who live in island territories under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) 

primary responsibilities are to manage the mineral resources located on the Nation's Outer 

Continental Shelf (OCS), collect revenue from the Federal OCS and onshore Federal and Indian 

lands, and distribute those revenues. 

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program 

administers the OCS competitive leasing program and oversees the safe and environmentally 

sound exploration and production of our Nation's offshore natural gas, oil and other mineral 

resources. The MMS Minerals Revenue Management meets its responsibilities by ensuring the 

efficient, timely and accurate collection and disbursement of revenue from mineral leasing and 

production due to Indian tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially 

affected parties and (2) carrying out its programs with an emphasis on working to enhance the 

quality of life for all Americans by lending MMS assistance and expertise to economic 

development and environmental protection.