Appendix C 

Attachment 1 

NMFS Biological Opinion 
Mr. Joseph Christop 

Regional Supervisor 

Minerals Managem 

1201 Elmwood Par1 

New Orleans, LA 7 

Dear Mr. Christophc 

This constitutes the : 

on our review of the 

Act (ESA) section 7 

Gas Leasing Progra 

Mexico. The biolo; 

actions are not like1 

under the jurisdictic 

However, NMFS a1 

Take Statement (IT 

prudent measures vt 

We look forward to 

cooperation to ensur 

designated critical h; 

action, as well as adc 

you to track the stat1 

fishery biologist, at ( 

Enclosures 

cc: F - Lindow 

File: 15 14-22.0.1 

Ref FlSERl2006, 

r 

t Service 

3oulevard 

23-2394 

UNITED STATES DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

NA-rIONAL MARINE FISHERIES SERVICE 

Southeast Regional Office 

263 1 3th venue South 

St. Petersburg, FL 33701 

(727) 824-53 12 FAX 824-5309 

JUN 29 2007 

tional Marine Fisheries Service's (NMFS) biological opinion (opinion) based 

[inerals Management Service's (MMS) request for formal Endangered Species 

,nsultation on the effects of the Five-Year Outer Continental Shelf Oil and 

(2007-2012) in the Central and Western Planning Areas of the Gulf of 

:al opinion concludes that the five-year leasing program and its associated 

to jeopardize the continued existence of threatened or endangered species 

of NMFS or destroy or adversely modify designated critical habitat. 

2ipates incidental take of sea turtle species and has issued an Incidental 

pursuant to section 7 of the ESA. This ITS contains reasonable and 

1 implementing terms and conditions to help minimize this take. 

operation with you on a pile driving study and workshop, and our continued 

he conservation of our threatened and endangered marine species and 

itat. We have enclosed other statutory requirements that may apply to this 

ional information on NMFS' Public Consultation Tracking System to allow 

of ESA consultations. If you have any questions, please contact Kyle Baker, 

!7) 824-53 12, or by e-mail at kyle.baker@noaa.gov. 

Regional Administrator 
Marine Mammal ~rolection Act (MMPA) Recommendations: The Endangered Species Act 

(ESA) section 7 procbss does not authorize incidental takes of listed or non-listed marine 

mammals. If such takes may occur, an incidental take authorization under MMPA section 101 

(a)(5) is necessary. ontact Ken Hollingshead of our IVMFS Headquarters' Protected Resources 

staff at (30 1) 7 1 3 for more information on MMPA permitting procedures. 

Additional 

Essential Fish ~abitdt (EFH) Recommendations: In addition to its protected species/critical 

habitat consultation iequirements with NMFS' Protected Resources Division (PRD) pursuant to 

section 7 of the ESA prior to proceeding with the proposed action the action agency must also 

consult with NMFS' Habitat Conservation Division (HCD) pursuant to the Magnuson-Stevens 

Fishery Conservatio 1 and Management Act's (MSA) requirements for essential fish habitat 

(EFH) consultation (16 U.S.C. 1855 (b)(2) and 50 CFR 600.905-.930, subpart K). The action 

agency should also e sure that the applicant understands the ESA and EFH processes; that ESA 

and EFH consultatio s are separate, distinct, and guided by different statutes, goals, and time 

lines for responding o the action agency; and that the action agency will (and the applicant may) 

receive separate con ! ultation correspondence on NMFS letterhead fiom HCD regarding their 

concerns andlor finalbzing EFH consultation. 

Gonsiderations for ESA Section 7 Consultations (Revised 12-6-2005) 

Site." From the "Choose Agency 

district. At "Enter Agency Permit 

year, hyphen, number. The COE is in the 

to PCTS-compatible "ORM." An example 

1. For the Jacksonville District, which has already 

converted to ORM, application numbers should be entered as SAJ (hyphen), followed by 

4-digit year by permit application numeric identifier with no preceding zeros. 

SAJ-2005-12345. 

Public Consultation 

by Corps districts that have not yet made the 

the 9-digit numeric identifier, or convert the 

number to 9 numeric digits by deleting all letters, hyphens, 

4-digit format (e.g., -04 to 2004); and adding additional 

to make a total of 9 numeric digits. E-g., AL05-982-F 

converts to 200500982; MS05-04401 -A converts to 200504401. PCTS questions should be 

directed to Eric Ha at Eric.FIawk@110aa.gov. Requests for usemame and password should be 

directed to April W lstencrofi (PCTSUsersupport@noaa.gov). :. -- 

Trackinn System (PCTS) Guidance: PCTS is an online query system 

allowing federal agencies and U.S. Army Corps of EngineersS(COE) permit applicants to track 

the status of NMFS donsu~tations under ESA section 7 and under MSA sections 305(b)2 and 

305(b)(4): Essential ish Habitat. Access PCTS via: w-~~v.mfs.noaa.~ov/pcts. Federal agencies t 

are required to enter n agency-specific usemame and password to query the Federal Agency 

Site. The Corps Pe 4 it Site allows COE permit applicants to check on the current status of 

Clean Water Act seclion 404 permit actions for which NMFS has conducted an ESA section 7 

consultation with the, COE since the beginning of the 2001 fiscal year (no password needed). 
Endangered Species Act - Section 7 Consultation 

Biological Opinion 

Action Agency: ~ Department of the Interior, Minerals Management Service 

Consulting Age cy: t National Oceanic and Atmospheric Administration, 

National Marine Fisheries Service, Southeast Regional 

Activity: 

Office, Protected Resources Division 

Gulf of Mexico Oil and Gas Activities: Five-Year Leasing 

Plan for Western and Central Planning Areas 2007-2012 

Approved by: 1 

Date Issued: ~ 

tree, Ph.D., Regional Administrator 

Fisheries Service, Southeast Regional Office 

St. Petersburg, Florida 

TABLE OF CONTENTS 

..................................................................................................... 2 

THE PROPOSED ACTION ................................................. 3 

BE AFFECTED ....................................... 26 

IN THE ACTION AREA ........................ 33 

10 CONCLUSION ....................................................................................................... 99 

11 INCIDEN AL TAKE STATEMENT (ITS) ........................................................ 99 t 

APPENDICES ............................................................................................................... 127 
1 INTRODUCTION 

The Outer Continental Shelf Lands Act (OCSLA) is the primary Act giving MMS its 

regulatory authority to establish policies and procedures for managing the oil and natural 

gas resources of the Outer Continental Shelf (OCS). The Energy Policy Act of 2005 

expanded and further defined the MMS role in energy development. Enacted on August 

8, 2005, the Energy Policy Act amended Section 8 of the OCSLA to authorize the 

Department of the Interior (DOI) to grant leases, easements, or rights-of-way on the OCS 

for the development and support of energy resources from sources other than oil and gas 

and to allow for alternate uses of existing facilities on the OCS. The Energy Policy Act 

grants MMS new responsibilities over Federal offshore renewable energy and related 

uses of the OCS. Although no projects are planned at this time, MMS is evaluating the 

potential of renewable energy resources on the OCS. 

The OCSLA requires DOI to prepare a five-year program that specifies the size, timing 

and location of areas to be assessed for Federal offshore natural gas and oil leasing. It is 

the role of DOI to ensure that the U.S. government receives fair market value for acreage 

made available for leasing and that any oil and gas activities conserve resources, operate 

safely, and take maximum steps to protect the environment. The last five-year program 

expires on June 30, 2007. MMS has formulated the next five-year program for 2007-

2012, including all leaseable U.S. Federal waters in the Central Planning Area (CPA) and 

the Western Planning Area (WPA). The Gulf of Mexico (GOM) Region of MMS has 

developed one EIS and a biological assessment for the eleven lease sales scheduled in the 

GOM under the 2007-2012 five-year program. 

 

Recent Lease Sale Consultation History 

The MMS has consulted with NMFS on five-year GOM oil and gas activities in the past. 

The most recent 5-year (2003-2007) consultation was formally requested by MMS in 

April 2002. A draft biological opinion was sent from NMFS to MMS in September 

2002, and the final biological opinion was issued to MMS in November 2002. 

The MMS has petitioned NMFS for programmatic rulemaking under the Marine 

Mammal Protection Act (MMPA) for Explosive Removal of Structures (EROS). This 

rulemaking also includes a programmatic section 7 consultation with NMFS under the 

ESA on these activities. The NMFS Proposed Rule for Explosive Removal of Structures 

operations was published in the Federal Register on April 7, 2006, and the ESA 

biological opinion was issued on August 28, 2006. Thus, EROS activities are not 

included in this consultation as part of the proposed action, but as part of the 

environmental baseline. 

Consultation History 

MMS submitted a biological assessment (BA) and request for section 7 consultation 

under the ESA on the OCS Leasing Program for 2007-2012 on June 5, 2006. In a letter 

dated July 28, 2006, NMFS requested additional information regarding the effects of 

pipelines and accidental oil spills on Gulf sturgeon critical habitat, the time of year of 

construction activities, pile driving, and other noise associated with the proposed action. 

2
On December 21, 2006, MMS resubmitted a BA. Subsequent discussions through e-mail 

exchanges and teleconferences were held to gather additional information and discuss 

potential impacts resulting from vessel strikes, oil spills, and construction activities on the 

OCS. NMFS initiated consultation with MMS on May 1, 2007. 

2 DESCRIPTION OF THE PROPOSED ACTION 

MMS is the administrative agency responsible for the mineral leasing of submerged OCS 

lands and for the supervision of offshore operations after lease issuance. The Western 

and Central GOM are currently major oil- and gas-producing areas. The proposed action 

is for the exploration, development and production, and associated activities as a result of 

MMS lease sales of available OCS blocks in the WPA and CPA. Eleven area wide oil 

and gas lease sales in the WPA and CPA of the GOM OCS are scheduled during the fiveyear period. Under the proposed five-year program, two sales would be held each year, 

one in the WPA and one in the CPA (Table 1). The purpose of the lease sale portion of 

the proposed action is to offer for lease those areas currently available for lease that may 

contain economically recoverable oil and natural gas resources. The proposed lease sales 

will provide qualified bidders the opportunity to bid upon and lease acreage in the GOM 

OCS for the exploration, development, and production of oil and natural gas. 

Table 1. Proposed WPA and CPA GOM OCS Lease Sales for 2007-2012. 

Lease Sale Number GOM Planning Area Year of Lease Sale 

204 WPA 2007 

205 CPA 2007 

206 CPA 2008 

207 WPA 2008 

208 CPA 2009 

210 WPA 2009 

213 CPA 2010 

215 WPA 2010 

216 CPA 2011 

218 WPA 2011 

222 CPA 2012 

2.1 Action Area 

The action area of the project includes all areas to be affected directly or indirectly by the 

action, and not merely the immediate area involved in the action (50 CFR 402.02). The 

action area is considered to include the Federal OCS waters in the WPA and CPA and all 

activities associated with the exploration, development, and production of those areas. 

The Federal OCS waters in the GOM begin 10 mi offshore of Florida; 3 mi offshore of 

Louisiana, Mississippi, and Alabama; and 10 mi offshore of Texas; and extend to the 

limits of the Exclusive Economic Zone (EEZ). The action area includes these waters as 

well as the coastal areas, ports, airspace, and waterways used by transport vessels related 

to the proposed action. 

3
The northern boundary of the CPA is defined by the Federal-State boundary offshore 

Louisiana, Mississippi, and Alabama (Figure 1). The eastern boundary of the CPA is 

defined by the offshore boundary between Alabama and Florida, proceeding 

southeasterly to 26.19°N. latitude, thence southwesterly to 25.6°N. latitude. The western 

boundary of the CPA is defined by the offshore boundary between Texas and Louisiana, 

proceeding southeasterly to 28.43°N. latitude, thence south southwesterly to 27.49°N. 

latitude, thence south southeasterly to 25.80°N. latitude. The southern boundary of the 

CPA is defined by the continental shelf boundary with Mexico as established by the 

"Treaty Between the Government of the United States of America and the Government of 

the United Mexican States on the Delimitation of the Continental Shelf in the Western 

GOM Beyond 200 Nautical Miles," which took effect in January 2001, and by the limit 

of the U.S. EEZ in the area east of the continental shelf boundary with Mexico. The CPA 

consists of approximately 66.3 million acres (ac), of which approximately 34.8 million ac 

are not currently leased. The CPA is located from 4.8 to 354 kilometers (km) offshore in 

water depths ranging from 4 to 3,400 meters (m). A typical lease sale in the CPA is 

projected to yield 0.776-1.292 billion barrels of oil (BBO) and 3.236-5.229 trillion cubic 

feet (tcf) of gas. The entire CPA will be considered for possible leasing except: 

• blocks that were formerly included within the Eastern Planning Area (EPA) 

and are within 100 mi of the Florida coast; 

• blocks that were formerly included within the EPA and are under an existing 

Presidential withdrawal through the year 2012 as well as subject to annual 

congressional moratoria; 

• blocks that are beyond the U.S. EEZ in the area known as the northern portion 

of the Eastern Gap; and 

• whole and partial blocks that lie within the 1.4-nmi buffer zone north of the 

continental shelf boundary between the United States and Mexico. 

The Central GOM Sale 205 area is the portion of the above-described CPA that was 

contained in the original Eastern GOM Sale 181 area, excluding blocks within 100 mi 

from the Florida coast. The Central GOM Sale 205 area consists of approximately 3.5 

million ac, of which approximately 2.7 million ac are not currently leased. This is the 

only sale currently scheduled in the Five-Year Program that is not area-wide. Central 

GOM Sale 205 is projected to yield 0.115-0.149 BBO and 0.430-0.557 tcf of gas. 

The western and northern boundaries of the WPA are defined by the Federal-State 

boundary offshore of Texas (Figure 1). The eastern boundary begins at the offshore 

boundary between Texas and Louisiana and proceeds southeasterly to 28.43°N latitude, 

thence south-southwesterly to 27.49°N latitude, thence south southeasterly to 25.80°N 

latitude. The southern boundary of the WPA is defined by the maritime boundary with 

Mexico that was established by the " Treaty Between the Government of the United 

States of America and the Government of the United Mexican States on the Delimitation 

of the Continental Shelf in the Western GOM Beyond 200 Nautical Miles," which took 

effect in January 2001. The WPA available consists of approximately 28.7 million ac, of 

which approximately 17.8 million ac are currently unleased. The WPA is located from 

 

4
Figure 1. GOM oil and gas leasing planning areas. 

14 to 357 km offshore in water depths ranging from 8-3,000 m. A typical lease sale in 

the WPA is projected to yield 0.242-0.423 BBO and 1.644-2.647 tcf of gas. The entire 

WPA will be considered for possible leasing except: 

• whole and partial blocks within the boundary of the Flower Garden Banks 

National Marine Sanctuary; and

• whole and partial blocks that lie within the 1.4-nmi buffer zone north of the 

continental shelf boundary between the United States and Mexico.

2.2 Project Activities and Operations 

The annual activity projections (Table 2) are estimates based on projected exploration 

and development activities, and impact-producing factors. These scenarios are only 

approximate because of future factors such as the contemporary economic marketplace, 

but represent the best assumptions and estimates of a set of future conditions that are 

considered reasonably foreseeable. Although the proposed action includes only proposed 

lease sales for the 2007-2012 five-year program, MMS bases estimates for all activities 

that are projected to occur from past, proposed, and future lease sales during the annual 

analysis period. 

2.2.1 Seismic Surveying 

Geophysical seismic surveys are performed to obtain information on surface and nearsurface geology and on subsurface geologic formations. The MMS recently completed a 

programmatic EA (PEA) (U.S. Dept. of the Interior, Minerals Management Service 2004) 

on geological and geophysical (G&G) activities on the GOM OCS, and is seeking 

regulations governing the harassment and nonserious injury of several species of marine 

mammals, including sperm whales, under the Marine Mammal Protection Act (MMPA). 

5
An MMPA petition package for G&G seismic operations, including an environmental 

assessment (EA), was sent to NMFS in December 2002. A petition was revised and 

NMFS issued a Notice of Intent in the Federal Register in November 2004. Rulemaking 

under the MMPA and a programmatic section 7 consultation under the ESA will follow 

completion of an EIS. The PEA includes a description of seismic surveying technologies 

and operations and is incorporated by reference. Currently, MMS implements seismic 

survey mitigation measures for marine mammals and sea turtles through term and 

conditions and conservation recommendations of previous lease sale biological opinions 

in the GOM (MMS NTL 2007-G02, APPENDIX A). 

Typical seismic surveying operations tow an array of airguns and a streamer (signal 

receiver cable) behind the vessel 5-10 m (16-33 ft) below the sea surface. Piston-type 

airguns are used to release compressed air to create impulses. The airgun array produces 

a burst of underwater sound by releasing compressed air into the water column that 

creates an acoustical energy pulse. Depending on survey type and depth to the target 

formations, the release of compressed air every couple of seconds creates a regular series 

of strong acoustic impulses separated by silent periods lasting 7-16 seconds. Airgun 

arrays are designed to focus the sound energy downward through the water column. 

Acoustic (sound) signals are reflected off the subsurface sedimentary layers and recorded 

near the water surface by hydrophones spaced within streamer cables. These streamer 

cables are often 3 mi (5 km) or greater in length. Vessel speed is typically 4.5-6 knots 

(about 4-8 mph) with gear deployed. The 3D surveys carried out by seismic vendors can 

consist of several hundred OCS blocks. Multiple-source and multiple-streamer 

technologies are used for 3D seismic surveys. A typical 3D survey might employ a dual 

array of 18 guns per array. Each array might emit a 3,000-in3

 burst of compressed air at 

2,000 pounds per square inch, generating approximately 4,500 kilojoule of acoustic 

energy for each burst. At 10 m (33 ft) from the source, the pressure experienced is 

approximately ambient pressure plus 1 atmosphere. The streamer array might consist of 

6-8 parallel cables, each 6,000-8,000 m (19,685-26,247 ft) long, spaced 75 m (246 ft) 

apart. 

High-resolution seismic surveys collect data on surficial geology used to identify 

potential shallow geologic hazards for engineering and site planning for bottom-founded 

structures. They are also used to identify environmental resources such as 

chemosynthetic community habitat. Deep-penetration, seismic surveys obtain data about 

geologic formations greater than 10,000 m (32,800 ft) below the seafloor. High-energy, 

marine seismic surveys include both 2D and 3D surveys. Data from 2D/3D surveys are 

used to map structural features to identify potential hydrocarbon traps. 

Approximately 400-800 blocks would be surveyed by deep seismic operations in the 

WPA, and approximately 1,000-2,000 blocks in the CPA from the proposed lease sales. 

For postlease seismic surveys, it is projected proposed lease sale in the WPA would result 

in about 20 VSP operations and about 2,000 mi surveyed by high-resolution seismic 

during the life of the proposed action. Proposed lease sales in the CPA would result in 

about 30 VSP operations and 3,000-4,000 mi surveyed by high-resolution seismic during 

the 40-year life of the leases.

6
MMS estimates that seismic surveys are projected to follow the same trend as exploration 

activities, which are projected to peak in 2008-2010, steadily decline until 2027, and 

remain relatively steady throughout the second half of the 40-year lease periods. During 

the first 2-4 years, it is projected annually there would be 95-130 VSP operations, 

12,500-16,500 miles surveyed by high-resolution seismic, and 1,500-3,000 blocks 

surveyed by deep seismic. During the second half of the lease periods, it is projected 

annually there would be 60-70 VSP operations, 6,200-8,300 mi surveyed by highresolution seismic, and 1,200-2,500 blocks surveyed by deep seismic. 

2.2.2 Construction 

In addition to various pieces of support equipment used in construction, such as vessels 

and cranes, pile driving is the primary method by which fixed structures are attached to 

the seafloor and provide stability for other support structures. Classified as either impact 

hammers or vibratory hammers, the design of the hammer assembly varies depending 

upon the medium powering the system; however, most assemblies contain a specialized 

control unit, piston, ram, and anvil. The impact hammer systems used for OCS-related 

work 

Table 2. Five-year annual projections in the Western and Central Planning Areas. 

Central Planning Area Western Planning Area 

Oil (Bbbl) 0.8-0.9 0.1-0.2 

Gas (tcf) 3.4-3.5 1.5-1.7 

Platforms Installed 108-114 41-48 

Exploration and Delineation Wells 188-263 107-156 

Production Development Wells 714-756 199-225 

Non-Producing Development Wells 107-113 30-34 

Vessels (round trips) 187,000–195,000 38,000-43,000 

Helicopter (Take Offs/Landings) 1,000,000 500,000 

Pipelines (km) 1,200 500 

 

predominantly utilize steam, pneumatic, or hydraulic assemblies. Most of the steam and 

pneumatic systems used in the GOM are limited to surface operations and have energy 

outputs (torque) ranging from 15,000-60,000 ft/lbs (20-82 kilonewton meters (kNm)). 

Hydraulic impact hammer systems can be used in both surface and sub-sea operations 

and most generally range from 11,000-370,000 ft/lbs (15-500 kNm). Almost all 

vibratory hammer systems use hydraulic power and due to their configuration, they can 

be used for both surface and sub-sea operations. 

Operators determine the type and size of pile driving equipment they require based upon 

the dimensions and design of the object being driven, water depths, equipment 

configuration (surface vs. sub-sea), sediment/substrate types, and the nature of the 

operations being conducted. Sediment types are varied in the GOM, but for shallow 

seabed activities such as these they are generally classified as consisting of muds 

(directly off river deltas/outlets), clays (mostly from the Louisiana-Texas border 

westward), and unconsolidated sands or silt (most of the shelf of the Northern GOM). 

7
Each sediment type offers differing levels of friction that must be overcome to allow the 

pile to penetrate to a sufficient depth. There are two primary pile-driving operations on 

the GOM OCS: 1) the setting of casing conductors (also know as drive pipe) for drilling 

operations; and 2) pile emplacement for the seabed securing of oil and gas structures and 

facilities. 

Casing Conductor (Drive Pipe) Installation 

Due to the frequency of exploratory and development drilling operations on the GOM 

OCS, the greatest number of pile-driving operations involve the setting or installation of 

casing conductors. Most casing conductors range in diameter from 12-36 in and have 

wall thicknesses that run from 1⁄4-3⁄4 in and are generally driven into the substrate until the 

conductor “meets refusal” or cannot be driven further without damage. Conductor 

casings can also be jetted into the seabed; however, the ease of mobilization of hammer 

drivers coupled with their speed of penetration, minimizes the use of jetting equipment, 

which requires more time to deploy and is often unviable due to water depth and 

sediment type. Most casing conductors driving operations occur in water depths <200 m 

(Figure 2) 

Figure 2. Current well distribution in the Western and Central Planning Areas. 

Structure/Facility Pile Installation 

Pile-driving operations are also conducted during oil and gas structure/facility 

installations on the GOM OCS. Structure piles are generally forged or rolled-sheet 

constructed steel pipes that range in diameter from 24-84 in and have wall thicknesses 

that run from 1⁄2-2 in. The piles are inserted into the legs of the platform jackets, along 

the inner wall of a caisson, or into sleeves configured into skirt bracings or seafloor 

templates for structures in certain deepwater/unstable environments. As with conductor 

casings, piles are generally driven into the substrate until it “meets refusal” or reaches a 

sufficient depth to ensure stability. Once set to the proper depth/refusal, the pile is then 

welded or grouted to the jacket leg, caisson, or sleeve to affix the facility to the seabed. 

Over the last 10 years, an average of 137 structures were installed annually in the Central 

8
and Western GOM with the majority concentrated on the shelf in water depths less than 

200 m (Figure 3). 

2.2.3 Development and Production Drilling 

A production well is drilled to exploit a discovered or known hydrocarbon field. 

Production wells can collectively be termed development wells. Production wells may be 

drilled from movable structures, such as jack-up rigs with fixed bottom-supported 

structures, vertically floating moored structures, floating production facilities (often 

called semi-submersibles), and drillships (dynamically positioned drilling vessels). The 

type of production structure installed at a site depends mainly on water depth. The 

number of wells per structure varies according to the type of production structure used, 

the prospect size, and the drilling/production strategy deployed for the drilling program 

and for resource conservation. Systems used to produce hydrocarbons can be fixed, 

floating, or sub-sea in deeper waters. 

Figure 3. Current platform distribution in the Western and Central Planning Areas. 

2.2.4 Production Platforms 

Offshore platforms are common structures used in the development of offshore oil and 

gas resources. The purpose of a platform is to house production and drilling equipment 

and living quarters for personnel (on manned platforms). A platform consists of two 

major components: an underwater jacket or tower and an above water deck. Platforms 

are fabricated onshore and then towed to an offshore location for installation. Facilities 

where platforms are fabricated are called platform fabrication yards. Production 

operations at fabrication yards include the cutting and welding of steel components and 

the construction of living quarters and other structures, as well as the assembly of 

platform components. Fixed platform fabrication can be subdivided into two major tasks: 

jacket fabrication and deck fabrication. Platform structures are transported offshore and 

installation may take place over a period of a week to a month at the beginning of a 

9
platform's 20- to 40-year production life. Derrick barges may be used to upright and 

position structures. Moorings and anchors are usually attached to keep the structure on 

station. Many platforms require that piles be driven to which the platform is attached by 

welding the components together. Commissioning activities involve all of the 

interconnecting and testing of the structure's modular components. 

Several types of production systems are used for offshore oil and gas development in the 

WPA and CPA, and types vary by water depth in which the structures may be found. A 

fixed platform is the most commonly used type of production system in the northern 

GOM. A fixed platform is a large skeletal structure extending from the bottom of the 

ocean to above the water level. It consists of a metal jacket that is attached to the ocean 

bottom with the piles, and a deck that accommodates drilling and production equipment 

and living quarters. Fixed platforms are typically installed in water depths up to 1,500 ft. 

A compliant tower is similar to a fixed platform; however, the underwater section is not a 

jacket but a narrow, flexible tower that, because of the flexibility of its structure, can 

move around in the horizontal dimension, thereby withstanding significant wave and 

wind impact. Compliant towers are typically installed in water depth from 1,000 to 2,000 

ft. Tension and mini-tension leg platforms do not have skeletal structures extending all 

the way to the ocean floor. Instead, they consist of floating structures that are kept in 

place by steel tendons attached to the ocean floor. Tension leg platforms can be used in 

different water depth ranges, up to 4,000 ft. A spar platform (a floating caisson) consists 

of a large vertical hull that is moored to the ocean floor with up to 20 lines. Above the 

hull sits the deck with production equipment and living quarters. At present, spar 

platforms are used in water depths up to 3,000 ft; however, present technology allows 

installation in waters as deep as 7,500 ft. 

A floating production system consists of a semi-submersible unit that is kept stationary 

either by anchoring with wire ropes and chains or by the use of rotating thrusters, which 

self propel the semi-submersible unit. Floating production systems are suited for 

deepwater production in water depths up to 7,500 ft. A sub-sea system consists of a 

single sub-sea well or several wells producing either to a nearby platform or to a distant 

production facility through a pipeline and manifold system. At present, sub-sea systems 

are used in water depths exceeding 5,000 ft. A floating production, storage, and 

offloading (FPSO) system consists of a large vessel that houses production equipment. It 

collects oil from several sub-sea wells, stores the oil, and periodically offloads it to a 

shuttle tanker. FPSO systems are particularly useful in development of remote oil fields 

where pipeline infrastructure is not available. 

2.2.5 Pipelines 

Pipelines are the primary method used to transport a variety of liquid and gaseous 

products between OCS production sites and onshore facilities servicing the GOM. These 

products include unprocessed (bulk) oil and gas; mixtures of gas and condensate; 

mixtures of gas and oil; processed condensate, oil, or gas; produced water; methanol; and 

a variety of chemicals used by the OCS industry offshore. It is expected that pipelines 

from most of the new offshore production facilities will connect to the existing pipeline 

infrastructure. Almost 100 percent of produced oil from a lease in the WPA or the CPA, 

10
out to 800 m, is expected to be transported via pipelines. MMS estimates pipelines will 

continue to be the primary means of transporting oil in the future, with approximately 92 

to 99 percent of the oil in the WPA, and 95 to 99 percent of the oil in the CPA 

transported through pipelines. 

Pipelines in the GOM are designated as either gathering lines or trunklines. Gathering 

lines are typically shorter segments of small-diameter pipelines that transport the well 

stream from one or more wells to a production facility or from a production facility to a 

central facility serving one or several leases (e.g., a trunkline or central storage or 

processing terminal). Trunklines are typically large-diameter pipelines that receive and 

mix similar production products and transport them from the production fields to shore. 

A trunkline may contain production from many discovery wells drilled on several 

hydrocarbon fields. The OCS-related pipelines near shore and onshore may merge with 

pipelines carrying materials produced in State territories for transport to processing 

facilities or to connections with pipelines located farther inland. 

2.2.6 Vessel Traffic 

Barges may be used offshore to transport oil and gas, supplies such as chemicals or 

drilling mud, or wastes between shore bases and offshore platforms. Barges are non-selfpropelled vessels that must be accompanied by one or more tugs. Because of this, barge 

transport is usually constrained to shallow waters of the GOM, close to the shoreline. 

Barging is used very infrequently as an interim transport system prior to the installation 

of a pipeline system. About 1 percent of the oil produced during the proposed actions in 

less than 60 m in both the WPA and the CPA is expected to be barged to shore over the 

40-year life of the leases. 

Shuttle tanker transport of OCS-produced oil is expected to be part of industry activities 

with 1 to 43 percent of oil transport in the CPA and 1 to 59 percent in the WPA. The 

expectation over the 2007-2046 lifetime of the proposed lease sales, is 1 to 5 percent and 

1 to 8 percent, respectively. Floating production, storage, and offloading (FPSO) systems 

and associated tanker transport of OCS-produced oil may use shuttle tankers or selfpropelled barges for transport to shore. 

Service vessels are one of the primary modes of transporting personnel between service 

bases and offshore platforms, drilling rigs, derrick barges, and pipeline construction 

barges. In addition to offshore personnel, service vessels carry cargo (i.e., freshwater, 

fuel, cement, barite, liquid drilling fluids, tubulars, equipment, and food) offshore. In 

general, the new type of vessels built will continue to be larger, deeper drafted, and more 

technologically advanced for deepwater activities. 

Service vessels that support various requirements of offshore oil and gas activities are 

categorized into supply, crew, and utility vessels. Large supply boats (50 to 70 m in 

length) with a capacity of 300 tons and draft of 3.5 m when loaded make up a large 

proportion of service vessels in the GOM. Crew and utility boats are about 30 m in 

length. Service vessels utilized in deep water include offshore supply vessels, fast supply 

vessels, and anchor-handling towing supply/mooring vessels; vessels employed in deep11
water operations typically are larger and/or faster than those usually supporting oil and 

gas operations in shallower water closer to shore. Compared to shelf-bound service 

vessels, deepwater service vessels have improved hull designs (increased efficiency and 

speed). Service vessels primarily used in deep water are offshore supply vessels, fast 

supply vessels, and anchor-handling/towing/supply/mooring vessels. Other deepwater 

specialty service vessels include well stimulation vessels. The offshore supply vessel and 

anchor-handling and anchor-handling/towing/supply/mooring vessels carry the same type 

of cargo (i.e., freshwater, fuel, cement, barite, liquid drilling fluids, tubulars, equipment, 

food, and miscellaneous supplies) but have different functions. As the number of deepwater development facilities located greater distances from shore increases, larger supply 

vessels with greater cargo carrying capacities and fast crew boats are being used. 

A trip is considered the transportation from a service base to an offshore site and back (a 

round trip). There are approximately eight round trips per week in support of drilling an 

exploration well and six round trips per week in support of drilling a development well. 

A platform is estimated to require one to two vessel trips per week over its 25-year 

production life. All trips are assumed to originate from the service base. Using some 

assumptions about the number of vessel crew members per boat, number of trips to 

existing as well as projected platforms, the number of development wells, the number of 

trips per well per week, transit times, and distances to sites from service bases, etc., the 

total number of service vessel trips has been estimated by MMS to be between 225,000-

238,000 round trips annually, with most trips occurring in the CPA. 

The five-year projections for annual vessel round trips are estimated to be 187,000-

195,000 in the CPA, with 4,627,000-5,887,000 service-vessel trips estimated to occur in 

the CPA over the 40-year OCS Program. In the WPA, five-year projections for annual 

vessel round trips is estimated to be 38,000-43,000, with 2,087,000-2,722,000 round trips 

estimated to occur over 40 years. 

2.2.7 Helicopters 

Helicopters are another mode of transporting personnel between service bases and 

offshore platforms, drilling rigs, derrick barges, and pipeline construction barges. 

Helicopters are routinely used for crew changes and at other times to transport 

management and special service personnel to offshore exploration and production sites. 

In addition, equipment and supplies are sometimes transported. Deepwater operations 

require helicopters that travel farther and faster, carry more personnel, are all-weather 

capable, and have lower operating costs. 

In the past, helicopter activity scenarios were based on round trips. However, industry 

needs and uses of helicopters has been changing and the flight logistics often involve 

numerous stops, and completing a true round trip (back to the original location) may take 

days or longer. Helicopter activity scenarios are now given in flight segments; that is, a 

take-off to a landing, regardless of length. In areas of heavy industry activity, helicopter 

segments can be a matter of minutes, hopping from one structure to the next. The 

projected annual number of helicopter segments in the CPA and WPA combined is 

1,500,000. Approximately 1,000,000 of these would occur in the CPA and 500,000 in 

12
the WPA. When calculated by depth, the shallowest depths (0-60 m) will have over 80 

percent of the helicopter activity over the 40-year OCS Program in the CPA. In the 

WPA, for the same 40-year OCS Program timeframe, shallow areas are projected to have 

over 75 percent of the helicopter activity. 

2.3 Proposed Harm Avoidance Measures for Protected Species 

MMS proposes the Protected Species Stipulation that is designed to minimize or avoid 

potential adverse impacts to federally protected species (e.g., sea turtles, marine 

mammals, and other listed species). The stipulations (or harm avoidance measures) 

considered in this biological opinion appear in the Appendices, and include the 

following: 

1. The MMS requires that all seismic surveys employ mandatory mitigation 

measures including the use of a 500-m “exclusion zone”, ramp-up and shutdown procedures, visual monitoring, and reporting. Seismic operations must 

immediately cease when whales are detected within the 500-m exclusion 

zone. Ramp-up procedures and seismic surveys may be initiated only during 

daylight unless alternate monitoring methods approved by MMS are used. 

2. The MMS will condition all permits issued to lessees and their operators to 

require them to collect and remove flotsam resulting from activities related to 

exploration, development, and production of this lease. 

3. The MMS will require that vessel operators and crews watch for marine 

mammals and sea turtles, reduce vessel speed to 10 knots or less when 

assemblages of cetaceans are observed, and maintain a distance of 90 m or 

greater from whales and a distance of 45 m or greater from small cetaceans 

and sea turtles. 

4. The MMS will condition all permits issued to lessees and their operators to 

require them to post signs in prominent places on all vessels and platforms 

used as a result of activities related to exploration, development, and 

production of this lease detailing the reasons (legal and ecological) why the 

release of debris must be eliminated. 

5. The MMS will require lessees and operators to instruct offshore personnel to 

immediately report all sightings and locations of injured or dead protected 

species (marine mammals and sea turtles) to the appropriate stranding 

network. If oil and gas industry activity is responsible for the injured or dead 

animals (e.g., because of a vessel strike), the responsible parties should remain 

available to assist the stranding network. If the injury or death is caused by a 

vessel collision, the responsible party must notify MMS within 24 hours of the 

strike. 

6. The MMS will require oil-spill contingency planning to identify important 

habitats, including designated critical habitat, used by listed species (e.g., sea 

13
turtle nesting beaches and piping plover critical habitat) and will require the 

strategic placement of spill cleanup equipment to be used only by personnel 

trained in less intrusive cleanup techniques on beach and bay shores. 

Notice to Lessees and Operators 

The MMS also issues Notices to Lessees and Operators (NTLs) in order to clarify, 

describe, or interpret regulation or OCS standards. The pertinent NTLs considered in this 

biological opinion, and that describe in greater detail some of the above-mentioned lease 

stipulations, include: 

1. “Implementation of Seismic Survey Mitigation Measures and Protected 

Species Observer Program” (NTL 2007-G02, APPENDIX A). 

2. “Vessel Strike Avoidance and Injured/Dead Protected Species Reporting” 

(NTL 2007-G04, APPENDIX B); 

3. “Marine Trash and Debris Awareness and Elimination” (NTL 2007-G03, 

APPENDIX C); and 

3 LISTED SPECIES AND CRITICAL HABITAT 

Table 3. Listed species and critical habitat in the action area. 

Common Name Scientific Name Status 

Marine Mammals 

 sperm whale Physeter macrocephalus endangered 

Sea Turtles 

 leatherback sea turtle Dermochelys coriacea endangered 

 Kemp’s ridley sea turtle Lepidochelys kempii endangered 

 hawksbill sea turtle Eretmochelys imbricata endangered 

 green sea turtlea Chelonia mydas threatened 

 loggerhead sea turtle Caretta caretta threatened 

Fish

 Gulf sturgeon Acipenser oxyrinchus 

desotoi 

threatened 

Critical Habitat 

 Gulf sturgeon 

 

Acipenser oxyrinchus 

desotoi 

Unit 8 

a

Green turtles are listed as threatened, except for breeding populations of green turtles in Florida and on the 

Pacific coast of Mexico, which are listed as endangered. 

The endangered and threatened species, and designated critical habitat under the 

jurisdiction of NMFS that appear in Table 3 occur in the action area. NMFS has 

designated critical habitat for the Gulf sturgeon in the action area.

14
3.1 Effects to Listed Species Considered and Discounted 

NMFS has analyzed several aspects of the proposed action during consultation with 

MMS for potential impacts to listed species and their habitats, and activities determined 

not to affect any listed species or designated critical habitat in the action area have been 

excluded from further analysis. Activities that may affect listed species or designated 

critical habitat were considered further for their potential to adversely affect listed 

species, and those determined to be insignificant and/or discountable are discussed in the 

following subsections. In addition to the direct effects of the action on listed species, this 

section also assesses the indirect effects of the proposed action, and the potential for any 

interrelated or interdependent effects of other activities (50 CFR 402.02). Indirect effects 

are those that are caused later in time, but are still reasonably certain to occur. 

Interrelated actions are those that are part of a larger action and depend upon the larger 

action for their justification. Interdependent actions are those that have no independent 

utility apart from the action under consideration (50 CFR 402.02). For activities that 

could potentially result in take, the proposed harm avoidance measures were also 

assessed for their effectiveness at reducing the likelihood of impacts to discountable 

levels, or by reducing the magnitude of potential impacts to insignificant levels. 

3.1.1 Vessel Strikes and Sperm Whales 

Increased traffic from support vessels involved in survey, service, or shuttle functions 

could increase the probability of collisions between vessels and sperm whales. It is 

estimated that a maximum of 238,000 vessel round trips will occur annually, of which 55 

percent are expected to occur in sperm whale habitat for vessels transiting in water depths 

greater than 200 m. Adverse reactions by whales to vessel activity have been recorded, 

and all are vulnerable to collisions with vessels, with incidents of strikes with juveniles 

and calves occurring more frequently than with adult animals. Some individuals may be 

able to detect and avoid underway vessels; however, the behavior of some individuals 

and age classes, and the behavioral characteristics of the species, behavioral state, or 

physical condition may result in an increased vulnerability to disturbance and injury from 

vessels operating at speeds over 10 knots (e.g., surface-active animals, sick animals, 

resting animals, and calfs). 

Vessels have the potential to affect sperm whales in deeper, pelagic waters (>200 m) 

where sperm whales are typically found in the GOM. A vessel’s operational speed 

influences the probability of animal detection and reaction time. Tugs are not believed to 

pose any significant threat of collision with sperm whales in the GOM because of their 

relatively slow transit speeds and operation in coastal waters where sperm whales are not 

found. Vessels are known to strike and injure larger sea life (e.g., sperm whales), mostly 

due to bow strikes (Laist et al. 2001) from vessels operating at faster speeds. Reported 

ship collision accounts suggest that serious injury to whales rarely occurs at speeds below 

10 knots (Laist et al. 2001). A vessel’s operational speed also influences the probability 

of animal detection and reaction time. At slower vessel speeds, a particular location 

ahead of the vessel is within visual range for a longer period of time before the vessel 

arrives at that location. For example, a vessel traveling at 16 knots that sees a whale 

1,000 m ahead will arrive at the whale’s position in 2.02 minutes; at 10 knots, the vessel 

will arrive at the whale’s position in 3.23 minutes. 

15
NMFS considers vessel approaches within 90 m to have the potential for harassment of 

marine mammals, and close approaches within tens of meters to have the potential to 

injure a marine mammal. A few individuals occurring within close proximity may be 

expected to be at risk of injury over the lifetime of the action. For example, the USS 

BURKELEY reported striking a whale of uncertain species at night on June 25, 2001, 

while undergoing high speed sea trials out of Pascagoula, Mississippi. Based on the 

location and size of the struck animal, it is believed to have been a sperm whale. 

Although vessel strikes do occur, these events appear to be infrequent with this species in 

offshore waters of the GOM, and are not expected to injure sperm whales from routine 

OCS vessel traffic associated with the proposed lease sales. However, there is a potential 

for sperm whales to be potentially harassed by passing vessels, and magnitude of this risk 

is considered in the following analysis. 

Although the ESA defines prohibited takes of listed animals to include harassment, the 

ESA does not define harassment, nor has NMFS defined this term through regulation. 

However, the MMPA of 1972, as amended, defines harassment as any act of pursuit, 

torment, or annoyance which has the potential to injure a marine mammal or marine 

mammal stock in the wild, or has the potential to disturb a marine mammal or marine 

mammal stock in the wild by causing disruption to behavioral patterns, including, but not 

limited to, migration, breathing, nursing, breeding, feeding, or sheltering (16 USC 

1362(18)(A)). 

NMFS is particularly concerned about harassment to individuals or populations that may 

manifest as an animal that fails to feed successfully, breed successfully (which can result 

from feeding failure), or complete its life history because of altered environmental 

variables or behavioral patterns. This analysis includes an examination of the responses 

at the level of individual animals that could result in harassment, and any population level 

consequences, such as a reduction in numbers, distribution, or reproduction. 

Behavioral reactions by whales to vessel activity have been recorded. Aerial surveys 

have confirmed that sperm whales are present in the GOM throughout the year. Sperm 

whales are the most often sighted and abundant cetaceans in offshore waters greater than 

200 m in depth. Based on active leases as of April 2006, 55 percent of those leases occur 

in water depths greater than 200 m (3,606 occur on water depths from 0-200 m; 4,501 

occur in water depth greater than 200 m); however, fewer leases occur in greater depths 

where sperm whales are found in higher densities. The mean density of sperm whales in 

the GOM is 0.35 per 100 km2

 and is used for this analysis. Due to the uncertainties 

regarding future vessel activity in deeper offshore waters that may affect sperm whales, a 

conservative estimate of potential harassment was calculated based on the following 

assumptions: 

• sperm whale density of .0035 km-2; 

• average offshore supply vessel measuring 70 x 16 m (0.070 x 0.016 km); 

• a harassment zone of 0.090 km; 

16
• a vessel may affect a sperm whale only once per round trip; 

• 55 percent of the maximum number of annual vessel trips will occur in water 

depth ≥200 m (130,900); 

• a random distribution of vessels and whales; and 

• whales and vessels are stationary at the surface. 

By adding a potential harassment zone to a vessel’s dimensions, the harassment 

dimensions of a vessel is a rectangular-shaped space measuring 0.160 x 0.106 km. A 

potential harassment area of 0.017 km2

 can be calculated for a single vessel, and a 

maximum harassment area of 2,225 km2 resulting from 130,900 vessel trips annually. 

Based on the mean sperm whale density in the GOM, an estimated 7.8 whales could 

potentially be found within the area of harassment annually. This estimate assumes a 

vessel is stationary; however, since vessels are underway between destinations, the 

probability for a randomly positioned, stationary whale to occur within the harassment 

zone of a vessel may be expected to increase as a vessel moves through the water, but the 

assumption that every vessel trip has the potential to affect a sperm whale is considered a 

conservative estimate of actual encounter rates. 

Although the above calculation provides an estimation of potential encounters and 

potential risks vessels may pose to sperm whales, whales are not randomly distributed 

and may be expected to occur in greater densities in some regions than others depending 

on oceanographic features and other factors affecting their distribution. Such changes in 

distribution may significantly affect where and when sperm whales may be encountered 

in the GOM. In reality, both sperm whales and vessels may have the opportunity to avoid 

one another. When encounters within 90 m do occur, sperm whales generally avoid 

underway vessels. 

To reduce the risk of encounters with sperm whales, MMS will implement NMFS’ vessel 

strike avoidance measures for protected species, as implemented in MMS NTL 2007-G04 

(APPENDIX B). With implementation of these measures, by maintaining a lookout for 

marine mammals and taking prudent actions to avoid collisions with them, NMFS 

believes that the likelihood of collisions between vessels and sperm whales will be 

reduced to insignificant levels. The observed avoidance of passing vessels by sperm 

whales is considered an advantageous response to avoid a potential threat, such as may 

occur in response to a predator such as killer whales, and is not expected to result in any 

significant response on migration, breathing, nursing, breeding, feeding, or sheltering to 

individuals, or have any consequences at the level of the population. With 

implementation of the vessel strike avoidance measures requirement to maintain a 

distance of 90 m from sperm whales, the potential for harassment of 7 or 8 whales 

annually is expected to be reduced to discountable levels. The potential for vessels 

striking sea turtles is discussed in the Effects of the Action in section 7 of this biological 

opinion. 

17
3.1.2 Effects of Seismic Surveys on Sea Turtles 

Studies regarding sea turtle hearing indicate that adult green, loggerhead, and Kemp's 

ridley turtles are sensitive to low to mid-frequency sounds. Other species of sea turtles 

with unknown hearing measurements have similar anatomies and are expected to have 

similar hearing ranges from those that have been measured. Although more hearing 

measurements are needed, the available data suggest that sea turtles are sensitive to 

frequencies from approximately 200 to 2,000 Hz. Some possible reactions to low 

frequency sounds include startle responses, rapid swimming, and swimming towards the 

surface at the onset of the sound. 

In a study measuring the responses of captive green and loggerhead sea turtles exposed to 

seismic airgun pulses at 10-sec intervals, the sea turtles increased their swimming speeds 

when exposed to levels above 166 dB re 1 μPa rms (McCauley et al. 2000). The behavior 

of the sea turtles became more erratic when received levels exceeded 175 dB re 1 μPa. 

Loggerhead sea turtles’ reactions to airguns held in an enclosure in a 10-m deep canal 

maintained a stand-off range of 30 m when exposed (O’Hara and Wilcox 1990). In 

another study, loggerhead sea turtles in a netted enclosure initially exhibited avoidance 

responses, but the avoidance response waned quickly (Moein et al. 1994). The change in 

behavior may have been due to habituation or reduced hearing sensitivity resulting from 

exposure to the noise. Other studies have also demonstrated that sea turtles behaviorally 

respond to exposure to noise, but the exposure levels and frequencies were not reported. 

Based on this information, sea turtles exposed to airgun pulses during the proposed 

survey may exhibit avoidance behavior. Studies suggest that avoidance may begin at 

levels above 166 dB re 1 μPa. Avoidance behavior may shorten the exposure period; 

however, the avoidance behavior could potentially disrupt normal behaviors. Although 

sea turtles may be expected to avoid the vicinity of seismic surveys, important habitat for 

sea turtles is overall associated with greater habitat quality (i.e., foraging habitat, juvenile 

habitat, and nesting beaches) along inshore and nearshore waters of the GOM. Any 

reactions of sea turtles to seismic surveys will be limited to an avoidance response in the 

vicinity of the surveys. Sea turtles behaviorally disrupted would be expected to resume 

their behavior after the seismic vessel has moved out of their immediate area, without 

significant impairment of feeding, migration, or other behaviors due to the short duration 

of exposure. Sea turtles also occur in greater abundances in closer to shore than in 

offshore waters, with the exception of foraging leatherbacks. With implementation of the 

MMS NTL No. 2007-G02 (APPENDIX A), the potentially for adverse effects to sea 

turtles will be reduced to discountable levels. 

3.1.3 Vessel Noise and Operation 

Vessels transmit noise through water and cumulatively are a significant contributor to 

increases in ambient noise levels in many areas. The dominant source of vessel noise 

from the proposed action is propeller cavitation, although other ancillary noises may be 

produced. The intensity of noise from service vessels is roughly related to ship size and 

speed. Large ships tend to be noisier than small ones, and ships underway with a full 

load (or towing or pushing a load) produce more noise than unladen vessels. Shipping 

traffic is most significant at frequencies from 20 to 300 Hz. Supertankers may generate 

18
peak sources levels of 185 to 190 dB re 1 μPa-m at about 7 Hz, and 160 dB re 1 μPa-m at 

frequencies of 20 to 60 Hz (Richardson et al. 1995). However, vessel traffic proposed in 

the action would produce lower levels of noise of 150 to 170 dB re 1 μPa-m at 

frequencies below 1,000 Hz. A tug pulling a barge generates 164 dB re 1 μPa-m when 

empty and 170 dB re 1 μPa-m loaded. A tug and barge underway at 18 km/h can 

generate broadband source levels of 171 dB re 1 μPa-m. A small crew boat produces 156 

dB re 1 μPa-m at 90 Hz. 

Increases in ambient noise are believed to be a potential threat for marine animals having 

greatest hearing sensitivities at lower frequencies that overlap with the main frequency 

level of energy produced by vessels, such as those of mysticetes, sea turtles, and fishes. 

Because vessel noise is continuous in the marine environment and can propagate great 

distances, masking and behavioral disturbance may be important effects on mysticetes, 

which can hear in the frequency range produced by vessels, but is not expected for 

odontocetes, such as sperm whales, which hear at higher frequencies. 

When higher frequencies are produced by vessel operation, they are generally of lower 

sound levels and do not propagate great distances. Any potential for disturbance from 

noise would be within close proximity to a vessel. Sperm whale responses to vessels may 

vary depending on the type of vessel involved. Sperm whales have been observed to 

reduce surface times with fewer blows per surface, exhibit shorter intervals between 

blows, and exhibit reduced frequency of dives with raised flukes, while other whales 

tolerate boat presence (Gordon et al. 1992). Many reactions observed by sperm whales 

appear to be associated with the level of noise produced by the vessels (Richardson et al. 

1995). The variable reactions by individual sperm whales may indicate some habituation 

on the part of those individuals that do not exhibit any reactions or may be indicative of 

individual variation in the behavioral patterns that are also associated with other marine 

mammals. Vessel noise and the presence of the vessel on the water may potentially 

affect the behavior of animals at relatively close distances where the vessel noise is more 

audible and the vessel may be visible from both below and above the surface. To reduce 

the risk of interactions with sperm whales, MMS will implement NMFS’ vessel strike 

avoidance measures for protected species, as implemented in MMS NTL 2007-G04 

(APPENDIX B). The NTL requires that vessel operators maintain a distance of 90 m 

from sperm whales that would reduce potential disturbances to this species to 

discountable levels. 

Effects on sea turtles are not expected since these species do not appear to greatly utilize 

environmental sound, at least at far distances in the open ocean. For sea turtles, 

avoidance appears to be more of a function of the physical presence of the vessel rather 

than the noise produced. To reduce the potential risk of interactions with sea turtles, 

MMS will implement NMFS’ vessel strike avoidance measures for protected species, as 

implemented in MMS NTL 2007-G04 (APPENDIX B). The NTL requires that vessel 

operators maintain a distance of 45 m from sea turtles that would reduce the potential 

effects from the physical presence of the vessels to discountable levels. 

19
It is not likely that lease sales in the WPA will result in any trips east of the Mississippi 

River that would affect the designated critical habitat of the Gulf sturgeon. In the CPA 

major navigation channels are excluded from critical habitat. Gulf sturgeon are not 

expected to be impacted by noise and direct physical impacts associated with vessel 

traffic associated with oil and gas activities in the WPA and CPA, since vessels are not 

expected to operate in this species’ habitat. 

3.1.4 Helicopter Operation 

Aircraft operation may ensonify broad areas, albeit for short periods at any one location 

while in transit. Helicopters produce sounds (resulting from rotors) generally below 500 

Hz with estimated source levels for a Bell 212 helicopter of 149 to 151 dB re 1 μPa-m 

(Richardson et al. 1995). At incident angles greater than 13° from the vertical, much of 

the incident noise from passing aircraft is reflected and does not penetrate the water 

(Urick 1972). Therefore, NMFS believes underwater noise from helicopters is generally 

very brief in duration, compared with the duration of audibility in the air, and the effects 

of underwater noise from helicopters on listed species of sperm whales, sea turtles, and 

Gulf sturgeon will be insignificant. 

Helicopter noise may affect sea turtles and sperm whales at the surface by eliciting startle 

responses due to increasing noise of a helicopter as it rapidly approaches, or due to the 

physical presence of the helicopter in the air. A hovering or circling aircraft would be 

expected to have a potentially greater affect on an animal. The modes by which an 

animal may be affected and the magnitude of those affects may not only depend on the 

helicopter operation (i.e., hovering or circling), but also on the species, hearing ability, or 

behavior of the animal. Routine OCS helicopter traffic would not be expected to disturb 

animals for extended periods, provided pilots do not alter their flight patterns to more 

closely observe or photograph marine mammals. Helicopters, while flying offshore, 

generally maintain altitudes above 700 ft during transit to and from a working area, and at 

an altitude of about 500 ft between platforms. The duration of the effects resulting from 

a startle response are expected to be short-term during routine flights, and the potential 

effects will be insignificant to sea turtles and sperm whales. 

3.1.5 Marine Debris 

Although the intentional discharge of marine debris is prohibited by law (30 CFR 250.40 

and MARPOL, Annex V, P.L. 100-220 [101 St. 1458]), accidental losses of debris do 

occur. Marine debris may originate from a variety of sources, yet the sources are usually 

not identified. A published study regarding shoreline trash at Padre Island National 

Seashore reported that approximately 10 percent of marine trash that washed ashore 

originated from offshore structures and/or vessels associated with the oil and gas 

industry. The incidental ingestion of marine debris and entanglement continue to 

adversely affect listed species and has been considered in preparation of the waste 

management plan for this project. MMS has proposed incorporation of an annual training 

and certification requirement for marine debris education and elimination for all offshore 

personnel, including the potential for adverse effects to listed species as required by 

MMS NTL 2007-G03 (APPENDIX C). NMFS believes that, with implementation of 

20
these measures, the potential for adverse impacts to listed species resulting from 

accidental discharges of trash and debris is discountable. 

3.1.6 Construction Noise

Gulf sturgeon are not expected to be found in any OCS area in which MMS-permitted 

pile driving activity could occur and will not be affected. Pile driving is not required for 

deepwater structure installations; however, few activities do occur in waters depths >200 

m. Because sperm whales are most commonly found in greater water depths > 1,000 m 

and most installations occur in shallower depths, the risk of sperm whales being affected 

by pile driving noise is considered discountable. Although vessel noise is a relatively 

constant contributor to ambient noise levels in the GOM, NMFS considers pile driving to 

be a louder and frequent noise source resulting from many, but transient point sources of 

noise from construction activities. The noise from these activities over the continental 

shelf and slope regions of the OCS has the greatest potential to affect listed species of sea 

turtles because the turtles are routinely found in these areas. 

Although pile-driving noise is not a continuous signal, repeated blows from the hammer 

(generally several seconds apart) could potentially affect the behavior of sea turtles in the 

area. Most structure installation requiring pile driving is expected to occur over the 

continental shelf in waters less than 400 m. Casing conductor driving operations occur in 

all water depths throughout the Central and Western GOM, but are concentrated on the 

shelf in waters less than 200 m in federal waters, and would therefore affect mostly listed 

species of sea turtles. 

Despite a gradual decrease during the past 4 or 5 years due to increased deepwater 

activities, statistics compiled over the last 10 years indicate that an average of over 1,100 

drilling operations are conducted annually in the Central and Western GOM. Since 

current MMS permitting and database processes do not track the method of conductor 

casing installation, it is assumed that the majority of the new drilling activities will use an 

impact hammer, as this is the preferred method of pile driving in the GOM. Pile-driving 

operations supporting oil and gas activities in the GOM involve the same basic principles 

as on-shore or coastal/near-shore activities; using specialized equipment to force an 

object into the sediment to affix an object that requires a stationary hold or foundation. 

Unlike on-shore activities, pile-driving operations on the GOM OCS involve the added 

complexity that comes with mobilizing, rigging, powering, and controlling complex 

equipment from platforms and vessels often dozens to thousands of feet above the 

substrate surface and in many instances, requiring operations in a sub-sea environment. 

Pile driving noise is a relatively broadband signal that may be audible to many species. 

There is a potential for sea turtles to avoid the ensonified area of pile driving. The sound 

waves produced by pile driving projects may deter animals by acting as an acoustic 

deterrent from the construction area. Deterrence may be an important effect of pile 

driving if it disrupts feeding, mating, or sheltering of individuals. Sea turtles are found in 

greater abundances in nearshore and inshore waters (Epperly et al. 2002) than offshore 

habitats where the proposed lease sale activities would potentially occur. The higher 

abundance of animals in coastal habitats is attributed to the higher quality of these coastal 

21
habitats for these species than those offshore. Although adverse effects on fishes have 

been reported in riverine and coastal habitats, these effects are not be expected for sea 

turtles in the offshore environment where they occur in lesser abundances, are more 

transient, and wouldn’t be expected to be attracted to an area where new construction is 

occurring. Additionally, new construction activities do not have an established marine 

community surrounding it that may attract marine life (e.g., oil and gas platforms already 

installed). Based on the above analysis, the likelihood of adverse affects on sea turtles 

from pile driving is considered to be discountable. 

3.1.7 Operation Noise 

Noise associated with decommissioning phases has been considered in a programmatic 

biological opinion completed in 2007. Geological and geophysical surveying is currently 

being considered in a programmatic consultation with MMS. All offshore activities on 

the OCS discussed in the section will not affect Gulf sturgeon because these activities are 

beyond the range of this species. Noise associated with pile driving and vessels are 

discussed above. The following considers the effects of common noise-producing 

activities resulting from the proposed action. 

Machinery Noise 

Machinery noise generated during the operation of fixed structures can be continuous or 

transient, and variable in intensity. Underwater noise from fixed structures ranges from 

about 20 to 40 decibels (dB) above background levels within a frequency spectrum of 30-

300 Hz at a distance of 30 m from the source (Gales 1982). These levels vary with type 

of platform and water depth. Underwater noise from platforms standing on metal legs 

would be expected to be insignificant of the small surface area in contact with the water 

and the placement of machinery on decks well above the water. 

Drilling 

Offshore drilling and production involves a variety of activities that produce underwater 

noises. Noises emanating from drilling activities from fixed, metal-legged platforms are 

considered not very intense and generally are at very low frequencies; near 5 Hz. Gales 

(1982) reported received levels of 119 to 127 dB re 1 μPa-m at near-field measurements. 

Noises from semi-submersible platforms also show rather low sound source levels. 

Drillships show somewhat higher noise levels than semi-submersibles as a result of 

mechanical noises generated through the drillship hull. The drillship Canmar Explorer II 

generates broadband source levels of 174 dB re 1 μPa-m. Noises associated with 

offshore oil and gas production are generally weak and typically at very low frequencies 

(~4.5 to 38 Hz) (Gales 1982). Although drilling noise may contribute to increases in 

ambient noise levels in the GOM while these activities are occurring, based on the 

available information, drilling is not expected to produce amplitudes sufficient to case 

hearing or behavioral effects in sea turtles or sperm whales; therefore, these effects are 

insignificant. 

3.1.8 Pipeline Construction Effects on Sea Turtles and Gulf Sturgeon 

The conventional construction season for pipeline installation is spring through fall 

(MMS 2006). Although sea turtles could be found in a pipeline construction area any 

22
time of year, potential impacts to Gulf sturgeon would be avoided during this 

construction period when Gulf sturgeon are found in riverine habitats. However, since 

this analysis is based upon anticipated activities in the future and the time of year of 

pipeline construction is unknown, it is assumed construction may occur any time. 

Construction of offshore pipelines will result in turbidity from burying of the pipeline as 

it is deployed by one barge as a second barge cuts (jets) the trenches and buries the 

pipeline. Sediment disturbance may also occur from jetting and trenching of the seafloor 

to lay the pipeline. The effects of turbidity are not expected to result in adverse impacts 

to listed species and are considered discountable. Any potential disturbance would be 

associated with short-term avoidance of the construction area. Any avoidance behavior 

that may occur is not expected to result in any detectable change in the foraging success 

or health of individuals. Sea turtles and Gulf sturgeon that may be in the area of pipeline 

installation or resting on the seafloor may experience temporary displacement from the 

area. Any disturbances to listed sea turtle species are expected to be insignificant, having 

no adverse impacts on listed species of sea turtles or Gulf sturgeon. 

Pipelines installed in water depths greater than 500 m use dynamically positioned barges 

that do not require anchoring to the sea floor or burying of the pipeline. Construction of 

pipelines is not expected to affect sperm whales, and the potential effects of vessel 

operations on listed species are discussed above. 

3.1.9 Brightly-lit platforms 

Lighting of offshore structures presents a potential danger to sea turtle hatchlings (Owens 

1983). Artificial lighting is a known threat to nesting sea turtles and interrupts the oceanfinding behavior of neonates. Hatchlings are known to be attracted to light (Witherington 

and Martin 1996, Witherington 1997). Platform lighting near nesting beaches could 

potentially affect nesting sea turtles and affect the behavior during the offshore migration 

of neonates if the structures are close to shore (Chan and Liew 1988). If this occurs, 

hatchling predation would increase dramatically since large birds and predacious fish also 

congregate around the platforms (Owens 1983, Witherington and Martin 1996). 

However, hatchlings may rely less on light cues offshore (Salmon and Wyneken 1990). 

Furthermore, attraction to offshore locations would be less problematic than attraction to 

landside locations, as the issue is to ensure that hatchlings head to sea rather than 

remaining onshore, or swimming parallel to shore where they are subject to a variety of 

mortality risks. Due to the location of MMS-permitted structures on the OCS, the effects 

of lighting from offshore structures on sea turtles are insignificant. 

3.1.10 Heavy Metals 

The environmental risks of chemical products used in GOM oil and gas operations have 

been analyzed and continue to be studied. Produced waters, drill muds, and drill cuttings 

are routinely discharged into offshore marine waters and are regulated by the U.S. 

Environmental Protection Agency’s (USEPA) National Pollutant and Discharge 

Elimination System permits. Most of the routinely discharged chemicals are diluted and 

dispersed when released in offshore areas and are not expected to directly affect any 

listed species. Accidental or intentional discharges of chemicals have the potential to be 

released in large volumes that may have deleterious short-term effects (hours to days) 

23
within the immediate marine environment. When an area is drilled, drilling fluids, drill 

cuttings, produced water, deck drainage, sanitary wastes, and domestic wastes are 

released. During production, additional waste streams include produced sand and well 

treatment, workover, and completion fluids. Minor discharges are also released from 

desalination units, blowout preventer fluids, boiler blowdown, and excess cement slurry. 

The chemical profiles, toxicity, and spill analyses have been summarized for some 

chemical compounds used for development and production and are detailed in MMS 

2001a and 2001b. The Lethal Concentration 50 (LC50), Effect Concentration 50 (EC50), 

and Lowest Observed Effect Concentration (LOEC) of these chemicals have been 

determined for algae, invertebrates, fish, and benthic organisms. Existing data show that 

heavy metal concentrations are often present in marine mammal and sea turtle tissues and 

organs from different locations around the world’s oceans. These heavy metals are also 

detected in eggs and hatchling sea turtles, as well as in the milk of lactating cetaceans. 

Neff (2002) provides a review of bioaccumulation in marine organisms and the effects of 

contaminants in oil well produced water. 

A comprehensive review of the wastes and pollutants generated by oil and gas activities 

and their toxicity to selected marine organisms may be found in NPDES evaluation 

criteria (USEPA 1993a, 1993b). Results of analysis conducted by Neff et al. (1989) 

looked at the accumulation of mercury and other metals in flounder, clams, and sand 

worms. Flounder did not accumulate any metals during exposure, and the soft-shell 

clams and sand worms had only slight increases of some metals. The authors noted that 

most of the accumulated metals were actually in the gut or gills as barite particles. These 

investigations led the researchers to conclude that metals associated with drilling fluid 

barite are not readily available by uptake from marine organisms. 

The quantitatively most important sources of mercury from exploration and production 

activities are drilling fluids and produced water. GOM-produced water rarely contains 

more than about 0.1 mg/L total mercury (about 10-fold higher than clean natural 

seawater). Nearly all the mercury in drilling muds is associated with barite, which is 

added to the mud as a weighting agent. The USEPA limit on mercury in barite is 1 part 

per million (ppm). The average mercury concentration in modern drilling mud barite is 

0.5 ppm. Most drilling muds and cuttings contain <0.1 ppm mercury. The mercury in 

produced water is diluted rapidly to background concentrations following discharge to 

the ocean. Most drilling muds discharged to US waters contain <1 ppm mercury. 

Sediments around offshore platforms in the GOM also rarely contain more than 1 ppm 

mercury. The background concentration of mercury in marine sediments from the GOM 

is usually <0.1 ppm. 

The mercury in drilling mud barite is sequestered in the solid barium sulfate in sulfide 

minerals, particularly sphelerite (ZnS). It is extremely insoluble and stable in this form, 

particularly in anoxic sediments. Very little mercury can be extracted from the barite, 

even under mildly acidic conditions, as might occur in the digestive tract of a marine 

animal. Because of its low bioavailability, mercury in barite is not readily available for 

24
methylation, and has consequently been shown to not be readily available in the food 

chain. 

Drilling fluids also contain barium and trace amounts of chromium, copper, cadmium, 

mercury, lead, and zinc. Chronic levels of these metals are localized to within 150 m of 

drilling structures (Kennicutt 1995). Statistically significant levels (when compared to 

background levels) of all these metals except chromium have been measured within 500 

m of GOM drilling sites (Boothe and Presley 1989), and dilution to background levels 

occurs within 1,000 m of the discharge point. 

Although elevated levels of mercury may occur within 500 m of drilling sites (Kennicutt 

1995), the chemical composition of the mercury in barite is not readily available to 

biological organisms (Neff et al. 1989). Data for mercury in tissues of fish and shellfish 

from the GOM show that marine animals collected near offshore platforms do not contain 

significantly higher concentrations of mercury than the same or related species from 

elsewhere in the GOM. Although there is some localized heavy metal contamination 

within 150 m of drilling sites, it is not expected to adversely affect larger, wide-ranging 

species such as sea turtles and sperm whales. No MMS-permitted oil and gas drilling 

occurs in or near Gulf sturgeon habitat, and no effects on this species or its designated 

critical habitat is expected, and not considered further in this biological opinion. 

3.1.11 Water Quality 

The main sources of wastes and discharges generated from oil and gas operations include 

treated sewage, treated wastewater, engine waste, biodegradable food waste, and solid 

waste. Wastes and discharges will result from operation of offshore structures and 

support vessels. Due to standard practices of the presence of curbs, drip pans, and other 

pollution prevention equipment on offshore structures, we believe the routine discharges 

of treated sewage, wastewater, and biodegradable food wastes will not adversely affect 

listed species of sea turtles, Gulf sturgeon, or sperm whales. 

Turbidity could result from construction activities, including pipelines, anchoring, and 

pile driving. The amount of turbidity from these type of activities is generally localized 

and short-term in duration. Listed species in any construction area may experience 

temporary displacement from the area, yet minor disturbance, if any, is expected to occur. 

Any disturbances to sea turtle, Gulf sturgeon, or sperm whales from turbidity are 

expected to be short term and insignificant, having no adverse impacts on these species. 

Some additional sources of turbidity may be associated with the anchoring of tugboats 

used in the GBS installation, placement of the GBS on the seafloor, and the installation of 

other LNG terminal components (e.g., steel jacket, mooring structures, and pipeline riser 

platform). All these effects are expected to result in minimal disturbance of the seafloor 

and any turbidity would be expected to have short term, minor effects on water quality. 

Insignificant effects to listed species are expected from these short-term increases in 

turbidity. 

25
Summary of Potential Adverse Effects to Listed Species 

In summary, NMFS concludes green, hawksbill, Kemp’s ridley, leatherback, and 

loggerhead sea turtles; and Gulf sturgeon are not likely to be adversely affected by the 

above effects associated with the proposed action; however, the effects of vessel strikes 

on sea turtles, and the effects of oil spills on all listed species in the action area are 

considered further in the Effects of the Action in Section 7 of this biological opinion. 

4 CRITICAL HABITAT LIKELY TO BE AFFECTED 

Gulf sturgeon critical habitat was jointly designated by NMFS and USFWS on April 18, 

2003 (50 CFR 226.214). Critical habitat is defined in section 3(5)(A) of the ESA as (i) 

the specific areas within the geographic area occupied by a species, at the time it is listed 

in accordance with the Act, on which are found those physical or biological features (I) 

essential to the conservation of the species and (II) that may require special management 

considerations or protection; and (ii) specific areas outside the geographic area occupied 

by a species at the time it is listed, upon a determination that such areas are essential for 

the conservation of the species. “Conservation” is defined in section 3(3) of the ESA as 

the use of all methods and procedures that are necessary to bring any endangered or 

threatened species to the point at which listing under the ESA is no longer necessary. 

Gulf sturgeon critical habitat includes areas within the major river systems that support 

the seven currently reproducing subpopulations (USFWS et al. 1995) and associated 

estuarine and marine habitats. Gulf sturgeon use the rivers for spawning, larval and 

juvenile feeding, adult resting and staging, and to move between the areas that support 

these components. Gulf sturgeon use the lower riverine, estuarine, and marine 

environments during winter months primarily for feeding and, more rarely, for inter-river 

migrations. Estuaries and bays adjacent to the riverine units provide unobstructed 

passage of sturgeon from feeding areas to spawning grounds. 

Fourteen areas (units) are designated as Gulf sturgeon critical habitat. Critical habitat 

units encompass approximately 2,783 river kilometers (km) and 6,042 km2 of estuarine 

and marine habitats and include portions of the following GOM rivers, tributaries, 

estuarine, and marine areas: 

Unit 1 = Pearl and Bogue Chitto Rivers in Louisiana and Mississippi 

Unit 2 = Pascagoula, Leaf, Bowie, Big Black Creek and Chickasawhay Rivers in 

Mississippi 

Unit 3 = Escambia, Conecuh, and Sepulga Rivers in Alabama and Florida 

Unit 4 = Yellow, Blackwater, and Shoal Rivers in Alabama and Florida 

Unit 5 = Choctawhatchee and Pea Rivers in Florida and Alabama 

Unit 6 = Apalachicola and Brothers Rivers in Florida 

Unit 7 = Suwannee and Withlacoochee Rivers in Florida 

Unit 8 = Lake Pontchartrain (east of causeway), Lake Catherine, Little Lake, the 

Rigolets, Lake Borgne, Pascagoula Bay and Mississippi Sound systems 

in Louisiana and Mississippi, and sections of the state waters within the 

GOM 

26
Unit 9 = Pensacola Bay system in Florida 

Unit 10 = Santa Rosa Sound in Florida 

Unit 11 = Nearshore GOM in Florida 

Unit 12 = Choctawhatchee Bay system in Florida 

Unit 13 = Apalachicola Bay system in Florida, and 

Unit 14 = Suwannee Sound in Florida 

Critical habitat determinations focus on those physical and biological features, or primary 

constituent elements (PCEs), that are essential to the conservation of the species (50 CFR 

424.12). Federal agencies must insure that their activities are not likely to result in the 

destruction or adverse modification of the PCEs within defined critical habitats. 

Therefore, proposed actions that may impact designated critical habitat require an 

analysis of potential impacts to each PCE. 

 PCEs identified as essential for the conservation of the Gulf sturgeon consist of: 

(1) Abundant food items, such as detritus, aquatic insects, worms, and/ or 

molluscs, within riverine habitats for larval and juvenile life stages; 

and abundant prey items, such as amphipods, lancelets, polychaetes, 

gastropods, ghost shrimp, isopods, molluscs and/or crustaceans, within 

estuarine and marine habitats and substrates for subadult and adult life 

stages; 

(2) Riverine spawning sites with substrates suitable for egg deposition 

and development, such as limestone outcrops and cut limestone banks, 

bedrock, large gravel or cobble beds, marl, soapstone, or hard clay; 

(3) Riverine aggregation areas, also referred to as resting, holding, and 

staging areas, used by adult, subadult, and/or juveniles, generally, but 

not always, located in holes below normal riverbed depths, believed 

necessary for minimizing energy expenditures during fresh water 

residency and possibly for osmoregulatory functions; 

(4) A flow regime (i.e., the magnitude, frequency, duration, seasonality, 

and rate-of-change of fresh water discharge over time) necessary for 

normal behavior, growth, and survival of all life stages in the riverine 

environment, including migration, breeding site selection, courtship, 

egg fertilization, resting, and staging, and for maintaining spawning 

sites in suitable condition for egg attachment, egg sheltering, resting, 

and larval staging; 

(5) Water quality, including temperature, salinity, pH, hardness, turbidity, 

oxygen content, and other chemical characteristics, necessary for 

normal behavior, growth, and viability of all life stages; 

27
(6) Sediment quality, including texture and other chemical characteristics, 

necessary for normal behavior, growth, and viability of all life stages; 

and 

(7) Safe and unobstructed migratory pathways necessary for passage 

within and between riverine, estuarine, and marine habitats (e.g., an 

unobstructed river or a dammed river that still allows for passage). 

As stated in the final rule designating Gulf sturgeon critical habitat (68 FR 13399), the 

following activities, among others, when authorized, funded or carried out by a federal 

agency, may destroy or adversely modify critical habitat: 

(1) Actions that would appreciably reduce the abundance of riverine prey 

for larval and juvenile sturgeon, or of estuarine and marine prey for 

juvenile and adult Gulf sturgeon, within a designated critical habitat 

unit, such as dredging; dredged material disposal; channelization; instream mining; and land uses that cause excessive turbidity or 

sedimentation; 

(2) Actions that would appreciably reduce the suitability of Gulf sturgeon 

spawning sites for egg deposition and development within a 

designated critical habitat unit, such as impoundment; hard-bottom 

removal for navigation channel deepening; dredged material disposal; 

in-stream mining; and land uses that cause excessive sedimentation; 

(3) Actions that would appreciably reduce the suitability of Gulf sturgeon 

riverine aggregation areas, also referred to as resting, holding, and 

staging areas, used by adult, subadult, and/or juveniles, believed 

necessary for minimizing energy expenditures and possibly for 

osmoregulatory functions, such as dredged material disposal upstream 

or directly within such areas; and other land uses that cause excessive 

sedimentation; 

(4) Actions that would alter the flow regime (the magnitude, frequency, 

duration, seasonality, and rate-of-change of fresh water discharge over 

time) of a riverine critical habitat unit such that it is appreciably 

impaired for the purposes of Gulf sturgeon migration, resting, staging, 

breeding site selection, courtship, egg fertilization, egg deposition, and 

egg development, such as impoundment; water diversion; and dam 

operations; 

(5) Actions that would alter water quality within a designated critical 

habitat unit, including temperature, salinity, pH, hardness, turbidity, 

oxygen content, and other chemical characteristics, such that it is 

appreciably impaired for normal Gulf sturgeon behavior, reproduction, 

growth, or viability, such as dredging; dredged material disposal; 

28
channelization; impoundment; in-stream mining; water diversion; dam 

operations; land uses that cause excessive turbidity; and release of 

chemicals, biological pollutants, or heated effluents into surface water 

or connected groundwater via point sources or dispersed non-point 

sources; 

(6) Actions that would alter sediment quality within a designated critical 

habitat unit such that it is appreciably impaired for normal Gulf 

sturgeon behavior, reproduction, growth, or viability, such as dredged 

material disposal; channelization; impoundment; in-stream mining; 

land uses that cause excessive sedimentation; and release of chemical 

or biological pollutants that accumulate in sediments; and 

(7) Actions that would obstruct migratory pathways within and between 

adjacent riverine, estuarine, and marine critical habitat units, such as 

dams, dredging, point-source-pollutant discharges, and other physical 

or chemical alterations of channels and passes that restrict Gulf 

sturgeon movement. 

4.1 Effects to Critical Habitat Considered and Discounted 

Gulf sturgeon critical habitat was designated in 2003 (50 CFR 226.214). Federal 

agencies must insure that their activities are not likely to result in the destruction or 

adverse modification of designated critical habitat through adverse effects to the primary 

constituent elements (PCEs) within defined critical habitats. The seaward boundary of 

Louisiana, Mississippi, and Alabama state coastal zones is 3 nautical miles into the 

territorial sea. Since Gulf sturgeon critical habitat extends only 1 mile beyond the barrier 

islands, it is fully within State waters. MMS lease sale activities primarily occur offshore 

and would not be expected to directly affect designated critical habitat for the Gulf 

sturgeon. However, pipelines and accidental spills were considered and discounted for 

their potential to adversely affect designated critical habitat. 

4.1.1 Pipelines 

Various entities regulate pipeline and other activity in State waters with either the COE or 

the Federal Energy Regulatory Commission (FERC) as the lead federal agency 

responsible for permitting such activities. Pipeline construction is therefore considered 

an indirect effect of the proposed action. If a pipeline were to be constructed through 

designated critical habitat for Gulf sturgeon, pipeline projects would have individual 

permits associated with them and would be subject to section 7 consultation under the 

ESA with FERC at that time. 

Increasingly, the trend is for new OCS pipelines to tie into existing systems rather than 

creating new landfalls. Over the last 10 years, there has been an average of about one 

new OCS pipeline-making landfall per year. Since 2002, only one new pipeline has 

come to shore in Louisiana from OCS-related activities, but none have been constructed 

in designated Gulf sturgeon critical habitat since its designation that have been a result of 

MMS actions. Based on this trend, few if any pipelines are expected to affect Gulf 

29
sturgeon critical habitat. However, considering the duration of proposed action, between 

the years 2007 and 2046, 80-118 new pipelines are projected in state waters as a result of 

the OCS Program. Of those pipelines, 32-47 (25-36 in Louisiana, 1-3 in Mississippi 

and/or Alabama) are projected to make landfall. Any pipelines that make landfall would 

most likely go ashore in Plaquemines Parish, Louisiana; Jackson County, Mississippi; or 

Mobile County, Alabama. Landfalls in Plaquemines Parish, Louisiana are not expected 

to affect critical habitat. However, the estimated three pipelines making landfall in 

Mississippi and Alabama may affect designated critical habitat unit 8. Currently, no 

pipelines are currently planned for construction in designated critical habitat; therefore, 

the following analysis is based upon the best available information for this type of 

activity with the expectation that a few pipelines may be constructed in designated 

critical habitat unit 8 over the 40-year lifetime of the action. 

Of the seven PCEs of Gulf sturgeon critical habitat discussed above, four are found in 

critical habitat unit 8: 1) abundant food items; 2) water quality; 3) sediment quality; and 

4) migratory pathways. The following PCEs were considered, and discounted for the 

potential to be adversely affected by the proposed lease sales: water quality, migratory 

pathways, and sediment quality. 

Abundant Food Items 

It is assumed that 0.32 ha of bottom is disturbed per kilometer of pipeline installed (MMS 

2006). Benthic organisms could be displaced or buried during jetting, trenching, and 

burial of pipelines. Because the pipeline is expected to be buried at a depth of 1 m in this 

area and the amount of material side-cast to create the trench is expect to range several 

inches in depth, invertebrates are expected to be able to recolonize the area by burrowing 

and/or tunneling back to the sediment depths in which they are usually found. The sidecasting of the material resulting from trenching and jetting is expected to be minor and 

insignificant since the invertebrates will be covered with a relatively shallow amount of 

sediment and the effects are expected to be short-term and insignificant. Following 

laying of pipelines in water depths <60 m, they are required to be buried. Pipelines are 

required to be buried at a minimum depth of 1 m and invertebrates will be able to 

colonize these sediments following burial, and will be available to foraging Gulf 

sturgeon. The impacted areas from the potential three pipelines would be expected to 

affect a very small percentage of the total area of unit 8. The impacts are expected to be 

temporary and not significantly affect the available foraging habitat in unit 8 while the 

impacts last. 

Anchoring of barges is usually required during construction of the pipeline. Anchor 

depressions can be as deep as 2.1 to 2.8 m. Each time an anchor is relocated, sediments 

and benthic organisms beneath the anchor would be displaced, suspended, or crushed. 

Anchoring methods are designed to minimize movement and sweeping of anchor chains; 

therefore, impacts are expected to be minimal. The areas affected would be available for 

recolonization of invertebrate fauna following anchor removal. The effects to 

invertebrates are expected to be temporary and insignificant. 

 

30
Potential pipeline leaks were also considered for the potential to affect abundant prey 

items, sediment quality, and water quality. Because natural gas would bubble to the 

surface and dissipate, no impacts to Gulf sturgeon critical habitat PCEs would be 

expected. 

Water Quality 

The disturbance of approximate 0.32 ha of bottom per kilometer of pipeline installed 

(MMS 2006) may affect water quality in the Gulf sturgeon critical habitat. Sediments 

would be suspended resulting in increased turbidity and a short-term degradation of water 

quality. The turbidity is expected to last from hours to days depending on the amount of 

sediment suspended. During jetting and trenching, and anchor placement, some turbidity 

is expected to occur. No changes in temperature, salinity, pH, hardness, oxygen content, 

or other chemical characteristics are expected from pipeline construction. NMFS does 

not expect measurable impacts to the status of this PCE, as a result of this project, within 

unit 8 or designated Gulf sturgeon critical habitat overall. 

Sediment Quality 

Sediment contaminants were considered for their potential to be suspended and settle 

during construction operations. The (USEPA) has assessed the overall condition of 

GOM estuaries (USEPA 1999). Based on this assessment, the USEPA concluded that 

there was an even distribution of estuary sites between the Florida panhandle and Corpus 

Christi, Texas, whose sediments were contaminated. However, the majority of estuarine 

ecosystems in all GOM states were identified as having fair to good sediment quality. 

 

Trenching and jetting will be used to lay the pipeline. Coarse sediment will settle out 

quickly (hours), while finer sediments may remain suspended for longer periods (hours to 

days). Because the depth of disturbance is rather shallow (the pipeline will be buried at a 

depth of 1 m), the quality of sediment settling out on the seafloor is expected to be the 

same as pre-disturbance conditions. 

Based on the available information regarding contaminants and depth of sediment 

disturbance, no adverse affects to sediment quality are expected from pipeline 

construction. 

Migratory Pathways 

Effects on migratory pathways of Gulf sturgeon critical habitat unit 8 were considered 

during consultation on this project. Because pipeline construction generally occurs in 

open waters of the GOM and will involve the localized disturbances related to the 

immediate area of pipe-laying activities, NMFS believes that the project will not reduce 

or eliminate Gulf sturgeon access to areas nearby or adjacent to the immediate project 

site. Therefore, pipeline construction is not expected to adversely affect migratory 

pathways. 

4.1.2 Accidental Spills 

Potential impacts on designated Gulf sturgeon critical habitat may occur from drilling and 

produced water discharges, accidental releases of fluids, blowouts, and oil spills. 

31
Designated critical habitat units 8 and 9 were considered in this analysis. If a spill were 

to contact Gulf sturgeon critical habitat, the PCEs of water quality, sediment quality, and 

abundant prey items may be affected. Coastal areas are generally more susceptible to 

contact by inshore or coastal spills. Inshore spills have a low probability of occurrence. 

Inshore vessel collisions may release fuel and lubricant oils and pipeline ruptures may 

release crude and condensate oil and may infrequently occur. Because of the floating 

nature of oil and the small tidal range in the coastal GOM, oil spills alone would typically 

have very little impact on benthic feeders such as the Gulf sturgeon. Unusually low tidal 

events, increased wave energy, or the use of oil dispersants increase the risk of impact 

with bottom-feeding and/or bottom-dwelling fauna. For this reason, dispersants are not 

usually used in response to coastal spills. Dispersants would likely be used for offshore 

spills and are expected to disperse about 65 percent of the volume of a spill. 

Additionally, considering the projected use of shore bases in support of activities 

resulting from a proposed action, very few of the estimated 46-102 coastal spills resulting 

from a proposed action in the CPA are likely to occur east of the Mississippi River. No 

coastal spills are projected to occur in Mississippi, Alabama, or Florida coastal waters as 

a result of a proposed action in the CPA. NMFS believes that the risk from inshore spills 

reaching Gulf sturgeon designated critical habitat and affecting any PCEs is so low, it is 

discountable. 

Offshore spills are generally far less likely to affect designated critical habitat than 

inshore or coastal spills because much of the critical habitat is protected from offshore 

spills by barrier islands, shoals, shorelines, and currents. Smaller spills (<42,000 gal) are 

not expected to significantly impact water quality in marine and coastal waters. The 

dilution and low toxicity of this pollution from small spills offshore are not expected to 

reach any designated critical habitat and is considered discountable. Larger spills, 

however, could impact coastal waters, depending on many factors such as the buoyancy 

of the spilled fluid, distance from the spill, currents, and duration of the spill. 

The potential risk of an oil spill affecting Gulf sturgeon critical habitat must be evaluated 

before the potential affects to PCEs can be assessed. Several factors reduce the 

probability of spilled oil affecting Gulf sturgeon critical habitat, including: 

• The inshore, riverine areas of designated habitat have a negligible probability 

of impact from accidental oil spills due to geographic protection, location east 

of the Mississippi River, and distance from major shore bases; 

• The floating nature of oil and the lack of large tidal ranges, as well as the 

influence of the Mississippi River outflow to help disperse slicks, diminishes 

the probability of significant impact of spilled oil on Gulf sturgeon critical 

habitat; 

• The very low probability (1 percent or less) of a large offshore oil spill 

contacting Gulf sturgeon critical habitat in all but the very westernmost area 

diminishes potential impact to, or alteration of, critical habitat; and 

• The extremely low probability of a coastal spill impacting east of the 

Mississippi River and north of Plaquemines Parish diminishes the probability 

of oil impacts to critical habitat. 

32
Based on oil spill modeling conducted by MMS, the coastal waters inhabited by the Gulf 

sturgeon are not expected to be at any significant risk from oil spills. The likelihood of a 

spill >42,000 gal occurring within the WPA and reaching designated critical habitat 

within 10 days after the spill incident is <0.5 percent and considered discountable (Table 

4). Very few of the estimated 46-102 coastal spills resulting from a proposed action in 

the CPA are likely to occur east of the Mississippi River. No coastal spills are projected 

to occur in Mississippi, Alabama, or Florida coastal waters as a result of a proposed 

action in the CPA. However, MMS conducted an analysis of the risk of a spill >42,000 

gal occurring offshore as a result of a proposed action and reaching the known locations 

of the Gulf sturgeon within 10 days after the spill event. It is estimated that there is a 1 

percent risk for Louisiana waters east of the Mississippi River to be affected by an oil 

slick within 10 days. Probabilities decrease below 1 percent to areas further to the east. 

Table 4. Probability (% chance) of oil spills ≥42,000 gal occurring and contacting 

designated Gulf sturgeon critical habitat within 10 days as a result of a WPA or CPA 

proposed action (“high” and “low” refer to production levels). 

Critical WPA CPA 

Habitat Unit Low High Low High 

8 <0.5 <0.5 1 1 

9 <0.5 <0.5 <0.5 <0.5 

Based on the above analysis, the likelihood of spill occurrence and subsequent contact 

with Gulf sturgeon designated critical habitat is extremely low; therefore the potential 

affect to any PCE is considered discountable. 

Summary of Effects to PCEs 

In summary, the PCEs of abundant prey items, water quality, sediment quality, and 

migratory pathways are not likely to be adversely affected by pipelines construction or 

accidental spills associated with the proposed action. The probability of an oil or 

chemical spill reaching designated Gulf sturgeon critical habitat is so low, it is considered 

discountable. 

 

5 STATUS OF AFFECTED SPECIES IN THE ACTION AREA 

The sea turtle subsections focus primarily on the Atlantic Ocean populations of these 

species since these are the populations that may be directly affected by the proposed 

action. However, these species are listed as global populations (with the exception of 

Kemp’s ridley and Florida green sea turtles, whose distribution is entirely in the Atlantic 

including the GOM), and the global status and trends of these species are included as 

well, in order to provide a basis for our final determination of the effects of the proposed 

action on the species as listed under the ESA. 

33
5.1 Loggerhead Sea Turtle 

The loggerhead sea turtle was listed as a threatened species throughout its global range on 

July 28, 1978. It was listed because of direct take, incidental capture in various fisheries, 

and the alteration and destruction of its habitat. Loggerhead sea turtles inhabit the 

continental shelves and estuarine environments along the margins of the Atlantic, Pacific, 

and Indian Oceans. In the Atlantic, developmental habitat for small juveniles is the 

pelagic waters of the North Atlantic and the Mediterranean Sea (NMFS and USFWS, 

1991a). Within the continental United States, loggerhead sea turtles nest from Texas to 

New Jersey. Major nesting areas include coastal islands of Georgia, South Carolina, and 

North Carolina, and the Atlantic and GOM coasts of Florida, with the bulk of the nesting 

occurring on the Atlantic coast of Florida. 

5.1.1 Pacific Ocean 

In the Pacific Ocean, major loggerhead nesting grounds are generally located in 

temperate and subtropical regions with scattered nesting in the tropics. Within the Pacific 

Ocean, loggerhead sea turtles are represented by a northwestern nesting aggregation 

located in Japan and a smaller southwestern nesting aggregation, which occurs in eastern 

Australia (Great Barrier Reef and Queensland) and New Caledonia (NMFS 2001a). 

There are no reported loggerhead nesting sites in the eastern or central Pacific Ocean 

basin. Data from 1995 estimated the Japanese nesting aggregation at 1,000 female 

loggerhead turtles (Bolten et al. 1996). Recent genetic analyses on female loggerheads 

nesting in Japan suggest that this “subpopulation” is comprised of genetically distinct 

nesting colonies (Hatase et al. 2002) with precise natal homing of individual females. As 

a result, Hatase et al. (2002) indicate that loss of one of these colonies would decrease the 

genetic diversity of Japanese loggerheads; recolonization of the site would not be 

expected on an ecological time scale. In Australia, long-term census data has been 

collected at some rookeries since the late 1960s and early 1970s, and nearly all the data 

show marked declines in nesting populations since the mid-1980s (Limpus and Limpus 

2003). The nesting aggregation in Queensland, Australia, was as low as 300 females in 

1997. 

Pacific loggerhead turtles are captured, injured, or killed in numerous Pacific fisheries 

including Japanese longline fisheries in the western Pacific Ocean and South China Seas; 

direct harvest and commercial fisheries off Baja California, Mexico; commercial and 

artisanal swordfish fisheries off Chile, Columbia, Ecuador, and Peru; purse seine fisheries 

for tuna in the eastern tropical Pacific Ocean; and California/Oregon drift gillnet 

fisheries. In addition, the abundance of loggerhead turtles on nesting colonies throughout 

the Pacific basin has declined dramatically over the past 10 to 20 years. Loggerhead 

turtle colonies in the western Pacific Ocean have been reduced to a fraction of their 

former abundance by the combined effects of human activities that have reduced the 

number of nesting females and reduced the reproductive success of females that manage 

to nest (e.g., due to egg poaching). 

5.1.2 Atlantic Ocean 

In the western Atlantic, most loggerhead sea turtles nest from North Carolina to Florida 

and along the Gulf coast of Florida. There are at least five western Atlantic 

34
subpopulations, divided geographically as follows: (1) A northern nesting subpopulation, 

occurring from North Carolina to northeast Florida at about 29oN; (2) a south Florida 

nesting subpopulation, occurring from 29oN on the east coast to Sarasota on the west 

coast; (3) a Florida Panhandle nesting subpopulation, occurring at Eglin Air Force Base 

and the beaches near Panama City, Florida; (4) a Yucatán nesting subpopulation, 

occurring on the eastern Yucatán Peninsula, Mexico (Márquez 1990, TEWG 2000); and 

(5) a Dry Tortugas nesting subpopulation, occurring in the islands of the Dry Tortugas, 

near Key West, Florida (NMFS 2001a). The fidelity of nesting females to their nesting 

beach is the reason these subpopulations can be differentiated from one another. Fidelity 

for nesting beaches makes recolonization of nesting beaches with sea turtles from other 

subpopulations unlikely. 

Life History and Distribution 

Past literature gave an estimated age at maturity of 21-35 years (Frazer and Ehrhart 1985, 

Frazer et al. 1994), with the benthic immature stage lasting at least 10-25 years. 

However, based on data from tag returns, strandings, and nesting surveys (NMFS 2001a), 

NMFS estimates ages of maturity ranging from 20-38 years with the benthic immature 

stage lasting from 14-32 years. 

Mating takes place in late March through early June, and eggs are laid throughout the 

summer, with a mean clutch size of 100-126 eggs in the southeastern United States. 

Individual females nest multiple times during a nesting season, with a mean of 4.1 

nests/individual (Murphy and Hopkins 1984). Nesting migrations for an individual 

female loggerhead are usually on an interval of 2-3 years, but can vary from 1-7 years 

(Dodd 1988). Generally, loggerhead sea turtles originating from the western Atlantic 

nesting aggregations are believed to lead a pelagic existence in the North Atlantic Gyre 

for as long as 7-12 years or more. Stranding records indicate that when pelagic immature 

loggerheads reach 40-60 cm straight-line carapace length they begin to live in coastal 

inshore and nearshore waters of the continental shelf throughout the U.S. Atlantic and 

GOM, although some loggerheads may move back and forth between the pelagic and 

benthic environment (Witzell 2002). Benthic immature loggerheads (sea turtles that have 

come back to inshore and nearshore waters), the life stage following the pelagic immature 

stage, have been found from Cape Cod, Massachusetts, to southern Texas, and 

occasionally strand on beaches in Northeastern Mexico. 

Tagging studies have shown loggerheads that have entered the benthic environment 

undertake routine migrations along the coast that are limited by seasonal water 

temperatures. Loggerhead sea turtles occur year round in offshore waters off North 

Carolina where water temperature is influenced by the Gulf Stream. As coastal water 

temperatures warm in the spring, loggerheads begin to immigrate to North Carolina 

inshore waters (e.g., Pamlico and Core Sounds) and also move up the coast (Epperly et 

al. 1995a, Epperly et al. 1995b, Epperly et al. 1995c), occurring in Virginia foraging 

areas as early as April and on the most northern foraging grounds in the Gulf of Maine in 

June. The trend is reversed in the fall as water temperatures cool. The large majority 

leave the Gulf of Maine by mid-September but some may remain in mid-Atlantic and 

Northeast areas until late fall. By December loggerheads have emigrated from inshore 

35
North Carolina waters and coastal waters to the north to waters offshore North Carolina, 

particularly off Cape Hatteras, and waters further south where the influence of the Gulf 

Stream provides temperatures favorable to sea turtles (≥11oC) (Epperly et al. 1995a, 

Epperly et al. 1995b, Epperly et al. 1995c). Loggerhead sea turtles are year-round 

residents of central and south Florida. 

Pelagic and benthic juveniles are omnivorous and forage on crabs, mollusks, jellyfish, 

and vegetation at or near the surface (Dodd 1988). Sub-adult and adult loggerheads are 

primarily coastal dwelling and typically prey on benthic invertebrates such as mollusks 

and decapod crustaceans in hard bottom habitats. 

Population Dynamics and Status 

A number of stock assessments (TEWG 1998, TEWG 2000, NMFS 2001a, Heppell et al. 

2003) have examined the stock status of loggerheads in the waters of the United States, 

but have been unable to develop any reliable estimates of absolute population size. 

Based on nesting data of the five western Atlantic subpopulations, the south Floridanesting and the northern-nesting subpopulations are the most abundant (TEWG 2000, 

NMFS 2001a). Between 1989 and 1998, the total number of nests laid along the U.S. 

Atlantic and Gulf coasts ranged from 53,014 to 92,182, annually with a mean of 73,751 

(TEWG 2000). On average, 90.7 percent of these nests were of the south Florida 

subpopulation and 8.5 percent were from the northern subpopulation (TEWG 2000). The 

TEWG (2000) assessment of the status of these two better-studied populations concluded 

that the south Florida subpopulation was increasing at that time, while no trend was 

evident (may be stable but possibly declining) for the northern subpopulation. A more 

recent, yet-to-be-published analysis of nesting data from 1989-2005 by the Florida 

Wildlife Research Institute indicates there is a declining trend in nesting at beaches 

utilized by the south Florida nesting subpopulation (2006 FWRI letter (McRae) to 

NMFS, based on statewide nesting beach survey data analyzed by FWRI). Nesting data 

obtained for the 2006 nesting season is also consistent with the decline in loggerhead 

nests (Meylan pers. comm. 2006). It is unclear at this time whether the nesting decline 

reflects a decline in population, or is indicative of a failure to nest by the reproductively 

mature females as a result of other factors (resource depletion, nesting beach problems, 

oceanographic conditions, etc.). NMFS has convened a new Turtle Expert Working 

Group for loggerhead sea turtles that will gather available data and examine the potential 

causes of the nesting decline and what the decline means in terms of population status. A 

final report by the loggerhead TEWG is expected by the end of summer 2007. 

For the northern subpopulations, recent estimates of loggerhead nesting trends in Georgia 

from standardized daily beach surveys showed significant declines ranging from 1.5 to 

1.9 percent annually (Mark Dodd, Georgia Department of Natural Resources, pers. 

comm., 2006). Nest totals from aerial surveys conducted by the South Carolina 

Department of Natural Resources showed a 3.3 percent annual decline in nesting since 

1980. Another consideration that may add to the importance and vulnerability of the 

northern subpopulation is the sex ratios of this subpopulation. NMFS scientists have 

estimated that the northern subpopulation produces 65 percent males (NMFS 2001a). 

However, new research conducted over a limited time frame has found opposing sex 

36
ratios (Wyneken et al. 2004) so further information is needed to clarify the issue. Since 

nesting female loggerhead sea turtles exhibit nest fidelity, the continued existence of the 

northern subpopulation is related to the number of female hatchlings that are produced. 

Producing fewer females will limit the number of subsequent offspring produced by the 

subpopulation. 

The remaining three subpopulations – Dry Tortugas, Florida Panhandle, and Yucatán – 

are much smaller, but also relevant to the continued existence of the species. Nesting 

surveys for the Dry Tortugas subpopulation are conducted as part of Florida’s statewide 

survey program. Survey effort has been relatively stable during the 9-year period from 

1995-2003 (although the 2002 year was missed). Nest counts ranged from 168-270 but 

with no detectable trend during this period (Florida Fish and Wildlife Conservation 

Commission, Florida Marine Research Institute, Statewide Nesting Beach Survey Data). 

Nest counts for the Florida Panhandle subpopulation are focused on index beaches rather 

than all beaches where nesting occurs. Currently, there is not enough information to 

detect a trend for the subpopulation (Florida Fish and Wildlife Conservation 

Commission, Florida Marine Research Institute, Index Nesting Beach Survey Database). 

Similarly, nesting survey effort has been inconsistent among the Yucatán nesting beaches 

and no trend can be determined for this subpopulation. However, there is some 

optimistic news. Zurita et al. (2003) found a statistically significant increase in the 

number of nests on seven of the beaches on Quintana Roo, Mexico, from 1987-2001 

where survey effort was consistent during the period. 

Threats 

The diversity of a sea turtle’s life history leaves them susceptible to many natural and 

human impacts, including impacts while they are on land, in the benthic environment, 

and in the pelagic environment. Hurricanes are particularly destructive to sea turtle nests. 

Sand accretion and rainfall that result from these storms as well as wave action can 

appreciably reduce hatchling success. For example, in 1992, all of the eggs over a 90-

mile length of coastal Florida were destroyed by storm surges on beaches that were 

closest to the eye of Hurricane Andrew (Milton et al. 1994). Also, many nests were 

destroyed during the 2004 hurricane season. Other sources of natural mortality include 

cold stunning and biotoxin exposure. 

Anthropogenic factors that impact hatchlings and adult female turtles on land, or the 

success of nesting and hatching include: beach erosion, beach armoring and nourishment, 

artificial lighting, beach cleaning, increased human presence, recreational beach 

equipment, beach driving, coastal construction and fishing piers, exotic dune and beach 

vegetation, and poaching. An increase in human presence at some nesting beaches or 

close to nesting beaches has led to secondary threats such as the introduction of exotic 

fire ants, feral hogs, dogs and an increased presence of native species (e.g., raccoons, 

armadillos, and opossums) which raid and feed on turtle eggs. Although sea turtle 

nesting beaches are protected along large expanses of the northwest Atlantic coast (e.g., 

Merritt Island, Archie Carr, and Hobe Sound National Wildlife Refuges), other areas 

along these coasts have limited or no protection. Sea turtle nesting and hatching success 

37
on unprotected high density east Florida nesting beaches from Indian River to Broward 

County are affected by all of the above threats. 

Loggerhead sea turtles are affected by a completely different set of anthropogenic threats 

in the marine environment. These include oil and gas exploration, coastal development, 

and transportation, marine pollution, underwater explosions, hopper dredging, offshore 

artificial lighting, power plant entrainment and/or impingement, entanglement in debris, 

ingestion of marine debris, marina and dock construction and operation, boat collisions, 

poaching, and fishery interactions. Loggerheads in the pelagic environment are exposed 

to a series of longline fisheries, which include the Atlantic highly migratory species 

(HMS) pelagic longline fisheries, an Azorean longline fleet, a Spanish longline fleet, and 

various longline fleets in the Mediterranean Sea (Aguilar et al. 1995, Bolten et al. 1996). 

Loggerheads in the benthic environment in waters off the coastal United States are 

exposed to a suite of fisheries in federal and state waters including trawl, purse seine, 

hook and line, gillnet, pound net, longline, and trap fisheries (see further discussion in 

Section 4.2, Environmental Baseline). 

5.1.3 Summary of Status for Loggerhead Sea Turtles 

The abundance of loggerhead turtles on nesting beaches throughout the Pacific basin has 

declined dramatically over the past 10 to 20 years. Data from 1995 estimated the 

Japanese nesting aggregation at 1,000 female loggerhead turtles (Bolten et al. 1996), but 

it has probably declined since 1995 and continues to decline (Tillman 2000). The nesting 

aggregation in Queensland, Australia, was as low as 300 females in 1997. 

In the Atlantic Ocean, absolute population size is not known, but based on extrapolation 

of nesting information, loggerheads are likely much more numerous than in the Pacific 

Ocean. NMFS recognizes five subpopulations of loggerhead sea turtles in the western 

north Atlantic based on genetic studies. Cohorts from all of these are known to occur 

within the action area of this consultation. The South Florida subpopulation may be 

critical to the survival of the species in the Atlantic Ocean because of its size (over 90 

percent of all U.S. loggerhead nests are from this subpopulation). In the past, this nesting 

aggregation was considered second in size only to the nesting aggregation on islands in 

the Arabian Sea off Oman (Ross 1979, Ehrhart 1989, NMFS and USFWS 1991a). 

However, the status of the Oman colony has not been evaluated recently and it is located 

in an area of the world where it is highly vulnerable to disruptive events such as political 

upheavals, wars, catastrophic oil spills, and lack of strong protections for sea turtles 

(Meylan et al. 1995). Given the lack of updated information on this population, the status 

of loggerheads in the Indian Ocean basin overall is essentially unknown. 

All loggerhead subpopulations are faced with a multitude of natural and anthropogenic 

effects that negatively influence the status of the species. Many anthropogenic effects 

occur as a result of activities outside of U.S. jurisdiction (i.e., fisheries in international 

waters). 

38
5.2 Green Sea Turtle 

Federal listing of the green sea turtle occurred on July 28, 1978, with all populations 

listed as threatened except for the Florida and Pacific coast of Mexico breeding 

populations, which are endangered. The nesting range of the green sea turtles in the 

southeastern United States includes sandy beaches of mainland shores, barrier islands, 

coral islands, and volcanic islands between Texas and North Carolina, the U.S. Virgin 

Islands (USVI) and Puerto Rico (NMFS and USFWS 1991b). Principal U.S. nesting 

areas for green sea turtles are in eastern Florida, predominantly Brevard through Broward 

counties (Ehrhart and Witherington 1992). Green sea turtle nesting also occurs regularly 

on St. Croix, USVI, and on Vieques, Culebra, Mona, and the main island of Puerto Rico 

(Mackay and Rebholz 1996). 

5.2.1 Pacific Ocean 

Green turtles are thought to be declining throughout the Pacific Ocean, with the exception 

of Hawaii, from a combination of overexploitation and habitat loss (Seminoff 2002). In 

the western Pacific, the only major (>2,000 nesting females) populations of green turtles 

occur in Australia and Malaysia, with smaller colonies throughout the area. Indonesia 

has a widespread distribution of green turtles, but has experienced large declines over the 

past 50 years. Hawaii green turtles are genetically distinct and geographically isolated, 

and the population appears to be increasing in size despite the prevalence of 

fibropapilloma and spirochidiasis (Aguirre et al., 1998 in Balazs and Chaloupka 2003). 

In the eastern Pacific, mitochondrial DNA analysis has indicated that there are three key 

nesting populations: Michoacan, Mexico; Galapagos Islands, Ecuador; and Islas 

Revillagigedos, Mexico (Dutton 2003). There is also sporadic green turtle nesting along 

the Pacific coast of Costa Rica. 

5.2.2 Atlantic Ocean 

Life History and Distribution 

The estimated age at sexual maturity for green sea turtles is between 20-50 years (Balazs 

1982, Frazer and Ehrhart 1985). Green sea turtle mating occurs in the waters off the 

nesting beaches. Each female deposits 1-7 clutches (usually 2-3) during the breeding 

season at 12-14 day intervals. Mean clutch size is highly variable among populations, but 

averages 110-115 eggs/nest. Females usually have 2-4 or more years between breeding 

seasons, whereas males may mate every year (Balazs 1983). After hatching, green sea 

turtles go through a post-hatchling pelagic stage where they are associated with drift lines 

of algae and other debris. At approximately 20 to 25 cm carapace length, juveniles leave 

pelagic habitats and enter benthic foraging areas (Bjorndal 1997). 

Green sea turtles are primarily herbivorous, feeding on algae and sea grasses, but also 

occasionally consume jellyfish and sponges. The post-hatchling, pelagic-stage 

individuals are assumed to be omnivorous, but little data are available. 

Green sea turtle foraging areas in the southeastern United States include any coastal 

shallow waters having macroalgae or sea grasses. This includes areas near mainland 

coastlines, islands, reefs, or shelves, and any open-ocean surface waters, especially where 

39
advection from wind and currents concentrates pelagic organisms (Hirth 1997, NMFS 

and USFWS 1991b). Principal benthic foraging areas in the southeastern United States 

include Aransas Bay, Matagorda Bay, Laguna Madre, and the Gulf inlets of Texas 

(Doughty 1984, Hildebrand 1982, Shaver 1994), the GOM off Florida from Yankeetown 

to Tarpon Springs (Caldwell and Carr 1957, Carr 1984), Florida Bay and the Florida 

Keys (Schroeder and Foley 1995), the Indian River Lagoon System, Florida (Ehrhart 

1983), and the Atlantic Ocean off Florida from Brevard through Broward counties 

(Wershoven and Wershoven 1992, Guseman and Ehrhart 1992). Adults of both sexes are 

presumed to migrate between nesting and foraging habitats along corridors adjacent to 

coastlines and reefs. 

Population Dynamics and Status 

The vast majority of green sea turtle nesting within the southeastern United States occurs 

in Florida (Meylan et al. 1995, Johnson and Ehrhart 1994). Green sea turtle nesting in 

Florida has been increasing since 1989 (Florida Fish and Wildlife Conservation 

Commission, Florida Marine Research Institute Index Nesting Beach Survey Database). 

Current nesting levels in Florida are reduced compared to historical levels, reported by 

Dodd (1981). However, total nest counts and trends at index beach sites during the past 

decade suggest the numbers of green sea turtles that nest within the southeastern United 

States are increasing. 

Although nesting activity is obviously important in determining population distributions, 

the remaining portion of the green turtle’s life is spent on the foraging and developmental 

grounds. Some of the principal feeding pastures in the western Atlantic Ocean include 

the upper west coast of Florida and the northwestern coast of the Yucatán Peninsula. 

Additional important foraging areas in the western Atlantic include the Mosquito and 

Indian River Lagoon systems and nearshore wormrock reefs between Sebastian and Ft. 

Pierce Inlets in Florida, Florida Bay, the Culebra archipelago and other Puerto Rico 

coastal waters, the south coast of Cuba, the Mosquito Coast of Nicaragua, the Caribbean 

Coast of Panama, and scattered areas along Colombia and Brazil (Hirth 1997). The 

summer developmental habitat for green turtles also encompasses estuarine and coastal 

waters from North Carolina to as far north as Long Island Sound (Musick and Limpus 

1997). 

There are no reliable estimates of the number of immature green sea turtles that inhabit 

coastal areas (where they come to forage) of the southeastern United States. However, 

information on incidental captures of immature green sea turtles at the St. Lucie Power 

Plant (they have averaged 215 green sea turtle captures per year since 1977) in St. Lucie 

County, Florida (on the Atlantic coast of Florida) show that the annual number of 

immature green sea turtles captured has increased significantly in the past 26 years (FPL 

2002). 

It is likely that immature green sea turtles foraging in the southeastern United States 

come from multiple genetic stocks; therefore, the status of immature green sea turtles in 

the southeastern United States might also be assessed from trends at all of the main 

regional nesting beaches, principally Florida, Yucatán, and Tortuguero. Trends at Florida 

40
beaches were previously discussed. Trends in nesting at Yucatán beaches cannot be 

assessed because of a lack of consistent beach surveys over time. Trends at Tortuguero 

(ca. 20,000-50,000 nests/year) showed a significant increase in nesting during the period 

1971-1996 (Bjorndal et al. 1999), and more recent information continues to show 

increasing nest counts (Troëng and Rankin 2004). Therefore, it seems reasonable that 

there is an increase in immature green sea turtles inhabiting coastal areas of the 

southeastern United States; however, the magnitude of this increase is unknown. 

Threats 

The principal cause of past declines and extirpations of green sea turtle assemblages has 

been the over-exploitation of green sea turtles for food and other products. Although 

intentional take of green sea turtles and their eggs is not extensive within the southeastern 

United States, green sea turtles that nest and forage in the region may spend large 

portions of their life history outside the region and outside U.S. jurisdiction, where 

exploitation is still a threat. However, there are still significant and ongoing threats to 

green sea turtles from human-related causes in the United States. These threats include 

beach armoring, erosion control, artificial lighting, beach disturbance (e.g., driving on the 

beach), pollution, foraging habitat loss as a result of direct destruction by dredging, 

siltation, boat damage, other human activities, and interactions with fishing gear. Sea 

sampling coverage in the pelagic driftnet, pelagic longline, southeast shrimp trawl, and 

summer flounder bottom trawl fisheries has recorded takes of green turtles. There is also 

the increasing threat from green sea turtle fibropapillomatosis disease. Presently, this 

disease is cosmopolitan and has been found to affect large numbers of animals in some 

areas, including Hawaii and Florida (Herbst 1994, Jacobson, 1990, Jacobson et al. 1991). 

5.2.3 Summary of Status for Atlantic Green Sea Turtles 

Green turtles range in the western Atlantic from Massachusetts to Argentina, including 

the GOM and Caribbean, but are considered rare in benthic areas north of Cape Hatteras 

(Wynne and Schwartz 1999). Green turtles face many of the same natural and 

anthropogenic threats as for loggerhead sea turtles described above. In addition, green 

turtles are also susceptible to fibropapillomatosis, which can result in death. In the 

continental United States, green turtle nesting occurs on the Atlantic coast of Florida 

(Ehrhart 1979). Recent population estimates for the western Atlantic area are not 

available. The pattern of green turtle nesting shows biennial peaks in abundance, with a 

generally positive trend during the ten years of regular monitoring since establishment of 

index beaches in Florida in 1989. However, given the species’ late sexual maturity, 

caution is warranted about over-interpreting nesting trend data collected for less than 15 

years. 

5.3 Kemp’s Ridley Sea Turtle 

The Kemp’s ridley was listed as endangered on December 2, 1970. Internationally, the 

Kemp’s ridley has been considered the most endangered sea turtle (Zwinenberg 1977, 

TEWG 2000). Kemp’s ridleys nest primarily at Rancho Nuevo, a stretch of beach in 

Mexico, Tamaulipas State. This species occurs mainly in coastal areas of the GOM and 

the northwestern Atlantic Ocean. Occasional individuals reach European waters 

41
(Brongersma 1972). Adults of this species are usually confined to the GOM, although 

adult-sized individuals sometimes are found on the east coast of the United States. 

5.3.1 Atlantic Ocean 

Life History and Distribution 

The TEWG (1998) estimates age at maturity from 7-15 years. Females return to their 

nesting beach about every 2 years (TEWG 1998). Nesting occurs from April into July 

and is essentially limited to the beaches of the western GOM, near Rancho Nuevo in 

southern Tamaulipas, Mexico. The mean clutch size for Kemp’s ridleys is 100 eggs/nest, 

with an average of 2.5 nests/female/season. 

Little is known of the movements of the post-hatchling stage (pelagic stage) within the 

GOM. Studies have shown the post-hatchling pelagic stage varies from 1-4 or more 

years, and the benthic immature stage lasts 7-9 years (Schmid and Witzell 1997). 

Benthic immature Kemp’s ridleys have been found along the eastern seaboard of the 

United States and in the GOM. Atlantic benthic immature sea turtles travel northward as 

the water warms to feed in the productive, coastal waters off Georgia through New 

England, returning southward with the onset of winter (Lutcavage and Musick 1985, 

Henwood and Ogren 1987, Ogren 1989). Studies suggest that benthic immature Kemp's 

ridleys stay in shallow, warm, nearshore waters in the northern GOM until cooling waters 

force them offshore or south along the Florida coast (Renaud 1995). 

Stomach contents of Kemp's ridleys along the lower Texas coast consisted of nearshore 

crabs and mollusks, as well as fish, shrimp, and other foods considered to be shrimp 

fishery discards (Shaver 1991). Pelagic stage Kemp’s ridleys presumably feed on the 

available Sargassum and associated infauna or other epipelagic species found in the 

GOM. 

Population Dynamics and Status 

Of the seven extant species of sea turtles in the world, the Kemp's ridley has declined to 

the lowest population level. Most of the population of adult females nest on the Rancho 

Nuevo beaches (Pritchard 1969). When nesting aggregations at Rancho Nuevo were 

discovered in 1947, adult female populations were estimated to be in excess of 40,000 

individuals (Hildebrand 1963). By the mid-1980s nest numbers were below 1,000 (with 

a low of 702 nests in 1985). However, observations of increased nesting with 6,277 nests 

recorded in 2000, 10,000 nests in 2005, and 12,143 nests recorded during the 2006 

nesting season (Gladys Porter Zoo nesting database) show the decline in the ridley 

population has stopped and the population is now increasing. 

A period of steady increase in benthic immature ridleys has been occurring since 1990 

and appears to be due to increased hatchling production and an apparent increase in 

survival rates of immature sea turtles beginning in 1990. The increased survivorship of 

immature sea turtles is attributable, in part, to the introduction of turtle excluder devices 

(TEDs) in the United States and Mexican shrimping fleets and Mexican beach protection 

efforts. As demonstrated by nesting increases at the main nesting sites in Mexico, adult 

ridley numbers have increased over the last decade. The population model used by 

42
TEWG (2000) projected that Kemp’s ridleys could reach the Recovery Plan’s 

intermediate recovery goal of 10,000 nesters by the year 2015. 

Next to loggerheads, Kemp’s ridleys are the second most abundant sea turtle in Virginia 

and Maryland waters, arriving in these areas during May and June (Keinath et al. 1987, 

Musick and Limpus 1997). The juvenile population of Kemp’s ridley sea turtles in 

Chesapeake Bay is estimated to be 211 to 1,083 turtles (Musick and Limpus 1997). 

These juveniles frequently forage in submerged aquatic grass beds for crabs (Musick and 

Limpus 1997). Kemp’s ridleys consume a variety of crab species, including Callinectes 

spp., Ovalipes spp., Libinia sp., and Cancer spp. Mollusks, shrimp, and fish are 

consumed less frequently (Bjorndal 1997). Upon leaving Chesapeake Bay in autumn, 

juvenile ridleys migrate down the coast, passing Cape Hatteras in December and January 

(Musick and Limpus 1997). These larger juveniles are joined there by juveniles of the 

same size from North Carolina sounds, as well as smaller juveniles from New York and 

New England, to form one of the densest concentrations of Kemp’s ridleys outside of the 

GOM (Musick and Limpus 1997, Epperly et al. 1995a, Epperly et al. 1995b). 

Threats 

Kemp’s ridleys face many of the same natural threats as loggerheads, including 

destruction of nesting habitat from storm events, natural predators at sea, and oceanic 

events such as cold-stunning. Although cold-stunning can occur throughout the range of 

the species, it may be a greater risk for sea turtles that utilize the more northern habitats 

of Cape Cod Bay and Long Island Sound. For example, in the winter of 1999-2000, there 

was a major cold-stunning event where 218 Kemp’s ridleys, 54 loggerheads, and 5 green 

turtles were found on Cape Cod beaches (R. Prescott, pers. comm. 2001). Annual coldstunning events do not always occur at this magnitude; the extent of episodic major coldstunning events may be associated with numbers of turtles utilizing Northeast waters in a 

given year, oceanographic conditions, and the occurrence of storm events in the late fall. 

Many cold-stunned turtles can survive if found early enough, but cold-stunning events 

can still represent a significant cause of natural mortality. 

Although changes in the use of shrimp trawls and other trawl gear have helped to reduce 

mortality of Kemp’s ridleys, this species is also affected by other sources of 

anthropogenic impacts similar to those discussed above. For example, in the spring of 

2000, five Kemp’s ridley carcasses were recovered from the same North Carolina 

beaches where 275 loggerhead carcasses were found. Cause of death for most of the 

turtles recovered was unknown, but the mass mortality event was suspected to have been 

from a large-mesh gillnet fishery operating offshore in the preceding weeks. The five 

ridley carcasses that were found are likely to have been only a minimum count of the 

number of Kemp’s ridleys that were killed or seriously injured as a result of the fishery 

interaction because it is unlikely that all of the carcasses washed ashore. 

5.3.2 Summary of Kemp’s Ridley Status 

The only major nesting site for ridleys is a single stretch of beach near Rancho Nuevo, 

Tamaulipas, Mexico (Carr 1963). The number of nests observed at Rancho Nuevo and 

nearby beaches increased at a mean rate of 11.3 percent per year from 1985 to 1999. 

43
Current totals are 12,059 nests in Mexico in 2006 (August 8, 2006, e-mail from Luis 

Jaime Peña - Conservation Biologist, Gladys Porter Zoo). Kemp’s ridleys mature at an 

earlier age (7-15 years) than other chelonids, thus “lag effects” as a result of unknown 

impacts to the non-breeding life stages would likely have been seen in the increasing nest 

trend beginning in 1985 (USFWS and NMFS 1992). 

The largest contributors to the decline of Kemp’s ridleys in the past were commercial and 

local exploitation, especially poaching of nests at the Rancho Nuevo site, as well as the 

GOM trawl fisheries. The advent of TED regulations for trawlers and protections for the 

nesting beaches has allowed the species to begin to rebound. Many threats to the future 

of the species remain, including interactions with fishery gear, marine pollution, foraging 

habitat destruction, illegal poaching of nests and potential threats to the nesting beaches 

from such sources as global climate change, development, and tourism pressures. 

5.4 Leatherback Sea Turtle 

The leatherback sea turtle was listed as endangered throughout its global range on June 2, 

1970. Leatherbacks are widely distributed throughout the oceans of the world, and are 

found in waters of the Atlantic, Pacific, and Indian Oceans (Ernst and Barbour 1972). 

Leatherback sea turtles are the largest living turtles and range farther than any other sea 

turtle species. The large size of adult leatherbacks and their tolerance to relatively low 

temperatures allows them to occur in northern waters such as off Labrador and in the 

Barents Sea (NMFS and USFWS 1995). Adult leatherbacks forage in temperate and 

subpolar regions from 71oN to 47oS latitude in all oceans and undergo extensive 

migrations to and from their tropical nesting beaches. In 1980, the leatherback 

population was estimated at approximately 115,000 adult females globally (Pritchard 

1982). That number, however, is probably an overestimation as it was based on a 

particularly good nesting year in 1980 (Pritchard 1996). By 1995, the global population 

of adult females had declined to 34,500 (Spotila et al. 1996). Pritchard (1996) also called 

into question the population estimates from Spotila et al. (1996), and felt they may be 

somewhat low, because it ended the modeling on data from a particularly bad nesting 

year (1994) while excluding nesting data from 1995, which was a good nesting year. 

However, Spotila et al. (1996) represents the best overall estimate of adult female 

leatherback population size. 

5.4.1 Pacific Ocean

Based on published estimates of nesting female abundance, leatherback populations have 

collapsed or have been declining at all major Pacific basin nesting beaches for the last 

two decades (Spotila et al. 1996, NMFS and USFWS 1998, Sarti et al. 2000, Spotila et al. 

2000). For example, the nesting assemblage on Terengganu, Malaysia – which was one 

of the most significant nesting sites in the western Pacific Ocean – has declined severely 

from an estimated 3,103 females in 1968 to two nesting females in 1994 (Chan and Liew 

1996). Nesting assemblages of leatherback turtles are in decline along the coasts of the 

Solomon Islands, a historically important nesting area (D. Broderick, pers. comm., in 

Dutton et al. 1999). In Fiji, Thailand, Australia, and Papua New Guinea (East Papua), 

leatherback turtles have only been known to nest in low densities and scattered colonies.

44
Only an Indonesian nesting assemblage has remained relatively abundant in the Pacific 

basin. The largest extant leatherback nesting assemblage in the Indo-Pacific lies on the 

north Vogelkop coast of Irian Jaya (West Papua), Indonesia, with over 3,000 nests 

recorded annually (Putrawidjaja 2000, Suarez et al. 2000). During the early-to-mid 

1980s, the number of female leatherback turtles nesting on the two primary beaches of 

Irian Jaya appeared to be stable. More recently, this population has come under 

increasing threats that could cause this population to experience a collapse that is similar 

to what occurred at Terengganu, Malaysia. In 1999, for example, local Indonesian 

villagers started reporting dramatic declines in sea turtle populations near their villages 

(Suarez 1999). Unless hatchling and adult turtles on nesting beaches receive more 

protection, this population will continue to decline. Declines in nesting assemblages of 

leatherback turtles have been reported throughout the western Pacific region, with nesting 

assemblages well below abundance levels observed several decades ago (e.g., Suarez 

1999). 

In the western Pacific Ocean and South China Seas, leatherback turtles are captured, 

injured, or killed in numerous fisheries, including Japanese longline fisheries. The 

poaching of eggs, killing of nesting females, human encroachment on nesting beaches, 

beach erosion, and egg predation by animals also threaten leatherback turtles in the 

western Pacific. 

In the eastern Pacific Ocean, nesting populations of leatherback turtles are declining 

along the Pacific coast of Mexico and Costa Rica. According to reports from the late 

1970s and early 1980s, three beaches on the Pacific coast of Mexico supported as many 

as half of all leatherback turtle nests for the eastern Pacific. Since the early 1980s, the 

eastern Pacific Mexican population of adult female leatherback turtles has declined to 

slightly more than 200 individuals during 1998-99 and 1999-2000 (Sarti et al. 2000). 

Spotila et al. (2000) reported the decline of the leatherback turtle population at Playa 

Grande, Costa Rica, which had been the fourth largest nesting colony in the world. 

Between 1988 and 1999, the nesting colony declined from 1,367 to 117 female 

leatherback turtles. Based on their models, Spotila et al. (2000) estimated that the colony 

could fall to less than 50 females by 2003-2004. Leatherback turtles in the eastern 

Pacific Ocean are captured, injured, or killed in commercial and artisanal swordfish 

fisheries off Chile, Columbia, Ecuador, and Peru, and purse seine fisheries for tuna in the 

eastern tropical Pacific Ocean, and California/Oregon drift gillnet fisheries. Because of 

the limited data, we cannot provide high-certainty estimates of the number of leatherback 

turtles captured, injured, or killed through interactions with these fisheries. However, 

between 8-17 leatherback turtles were estimated to have died annually between 1990 and 

2000 in interactions with the California/Oregon drift gillnet fishery; 500 leatherback 

turtles are estimated to die annually in Chilean and Peruvian fisheries; 200 leatherback 

turtles are estimated to die in direct harvests in Indonesia; and before 1992, the North 

Pacific driftnet fisheries for squid, tuna, and billfish captured an estimated 1,000 

leatherback turtles each year, killing about 111 of them each year. 

Although all causes of the declines in leatherback turtle colonies in the eastern Pacific 

have not been documented, Sarti et al. (1998) suggest that the declines result from egg 

45
poaching, adult and sub-adult mortalities incidental to high seas fisheries, and natural 

fluctuations due to changing environmental conditions. Some published reports support 

this suggestion. Sarti et al. (2000) reported that female leatherback turtles have been 

killed for meat on nesting beaches like Píedra de Tiacoyunque, Guerrero, Mexico. Eckert 

(1997) reported that swordfish gillnet fisheries in Peru and Chile contributed to the 

decline of leatherback turtles in the eastern Pacific. The decline in the nesting population 

at Mexiquillo, Mexico, occurred at the same time that effort doubled in the Chilean 

driftnet fishery. In response to these effects, the eastern Pacific population has continued 

to decline, leading some researchers to conclude that the leatherback is on the verge of 

extinction in the Pacific Ocean (e.g., Spotila et al. 1996, Spotila et al. 2000). The NMFS 

assessment of three nesting aggregations in its February 23, 2004, biological opinion 

supports this conclusion: If no action is taken to reverse their decline, leatherback sea 

turtles nesting in the Pacific Ocean either have high risks of extinction in a single human 

generation (for example, nesting aggregations at Terrenganu and Costa Rica) or they 

have a high risk of declining to levels where more precipitous declines become almost 

certain (e.g., Irian Jaya) (NMFS 2004a). 

5.4.2 Atlantic Ocean 

In the Atlantic Ocean, leatherbacks have been recorded as far north as Newfoundland, 

Canada, and Norway, and as far south as Uruguay, Argentina, and South Africa (NMFS 

2001). Female leatherbacks nest from the southeastern United States to southern Brazil 

in the western Atlantic and from Mauritania to Angola in the eastern Atlantic. The most 

significant nesting beaches in the Atlantic, and perhaps in the world, are in French 

Guiana and Suriname (NMFS 2001). Genetic analyses of leatherbacks to date indicate 

that within the Atlantic basin there are genetically different nesting populations; the St. 

Croix nesting population (U.S. Virgin Islands), the mainland nesting Caribbean 

population (Florida, Costa Rica, Suriname/French Guiana), and the Trinidad nesting 

population (Dutton et al. 1999). When the hatchlings leave the nesting beaches, they 

move offshore but eventually utilize both coastal and pelagic waters. Very little is known 

about the pelagic habits of the hatchlings and juveniles, and they have not been 

documented to be associated with the Sargassum areas as are other species. Leatherbacks 

are deep divers, with recorded dives to depths in excess of 1,000 m (Eckert et al. 1999, 

Hayes et al. 2004). 

Life History and Distribution

Leatherbacks are a long-lived species, living for over 30 years. They reach sexual 

maturity somewhat faster than other sea turtles (except Kemp’s ridley), with an estimated 

range from 3-6 years (Rhodin 1985) to 13-14 years (Zug and Parham 1996). They nest 

frequently (up to 10 nests per year) during a nesting season and nest about every 2-3 

years. During each nesting, they produce 100 eggs or more in each clutch and, thus, can 

produce 700 eggs or more per nesting season (Schultz 1975). However, a significant 

portion (up to approximately 30 percent) of the eggs can be infertile. Thus, the actual 

proportion of eggs that can result in hatchlings is less than this seasonal estimate. The 

eggs incubate for 55-75 days before hatching. Based on a review of all sightings of 

leatherback sea turtles of <145 cm curved carapace length (ccl), Eckert (1999) found that 

leatherback juveniles remain in waters warmer than 26oC until they exceed 100 cm ccl. 

46
Although leatherbacks are the most pelagic of the sea turtles, they enter coastal waters on 

a seasonal basis to feed in areas where jellyfish are concentrated. Leatherback sea turtles 

feed primarily on cnidarians (medusae, siphonophores) and tunicates. 

Evidence from tag returns and strandings in the western Atlantic suggests that adult 

leatherback sea turtles engage in routine migrations between boreal, temperate, and 

tropical waters (NMFS and USFWS 1992). A 1979 aerial survey of the outer continental 

shelf from Cape Hatteras, North Carolina, to Cape Sable, Nova Scotia showed 

leatherbacks to be present throughout the area with the most numerous sightings made 

from the Gulf of Maine south to Long Island. Leatherbacks were sighted in waters where 

depths ranged from 1-4,151 m, but 84.4 percent of sightings were in areas where the 

water was less than 180 m deep (Shoop and Kenney 1992). Leatherbacks were sighted in 

waters of a similar sea surface temperature as loggerheads; from 7-27.2oC (Shoop and 

Kenney 1992). However, this species appears to have a greater tolerance for colder 

waters because more leatherbacks were found at the lower temperatures (Shoop and 

Kenney 1992). This aerial survey estimated the in-water leatherback population from 

near Nova Scotia, Canada to Cape Hatteras, North Carolina at approximately 300-600 

animals. 

Population Dynamics and Status

The status of the Atlantic leatherback population is less clear than the Pacific population. 

The total Atlantic population size is undoubtedly larger than in the Pacific, but overall 

population trends are unclear. In 1996, the entire western Atlantic population was 

characterized as stable at best (Spotila et al. 1996), with numbers of nesting females 

reported to be on the order of 18,800. A subsequent analysis by Spotila (pers. comm.) 

indicated that by 2000, the western Atlantic nesting population had decreased to about 

15,000 nesting females. The nesting aggregation in French Guiana has been declining at 

about 15 percent per year since 1987 (NMFS 2001). However, from 1979-1986, the 

number of nests was increasing at about 15 percent annually which could mean that the 

current 15 percent decline could be part of a nesting cycle which coincides with the 

erosion cycle of Guiana beaches described by Schultz (1975). In Suriname, leatherback 

nest numbers have shown large recent increases (with more than 10,000 nests per year 

since 1999 and a peak of 30,000 nests in 2001), and the long-term trend for the overall 

Suriname and French Guiana population may show an increase (Girondot 2002 in 

Hilterman and Goverse 2003). The number of nests in Florida and the U.S. Caribbean 

has been increasing at about 10.3 percent and 7.5 percent, respectively, per year since the 

early 1980s, but the magnitude of nesting is much smaller than that along the French 

Guiana coast (NMFS 2001). Also, because leatherback females can lay 10 nests per 

season, the recent increases to 400 nests per year in Florida may represent as few as 40 

individual female nesters per year. 

In summary, the conflicting information regarding the status of Atlantic leatherbacks 

makes it difficult to characterize the current status. Numbers at some nesting sites are 

increasing, but are decreasing at other sites. Tag return data emphasize the wide-ranging 

nature of the leatherback and the link between South American nesters and animals found 

47
in U.S. waters. For example, a nesting female tagged May 29, 1990, in French Guiana 

was later recovered and released alive from the York River, Virginia. Another nester 

tagged in French Guiana on June 21, 1990, was later found dead in Palm Beach, Florida 

(STSSN database). Genetic studies performed within the Northeast Distant Fishery 

Experiment indicate that the leatherbacks captured in the Atlantic highly migratory 

species pelagic longline fishery were primarily from the French Guiana and Trinidad 

nesting stocks (over 95 percent). Individuals from West African stocks were surprisingly 

absent. 

There are a number of problems contributing to the uncertainty of the leatherback nest 

counts and population assessments. The nesting beaches of the Guianas (Guyana, French 

Guiana, and Suriname) and Trinidad are by far the most important in the western 

Atlantic. However, beaches in this region undergo cycles of erosion and reformation, so 

that the nesting beaches are not consistent over time. Additionally, leatherback sea 

turtles do not exhibit the same degree of nest-site fidelity demonstrated by loggerhead 

and other hardshell sea turtles, further confounding analysis of population trends using 

nesting data. Reported declines in one country and reported increases in another may be 

the result of migration and beach changes, not true population changes. Nesting surveys, 

as well as being hampered by the inconsistency of the nesting beaches, are themselves 

inconsistent throughout the region. Survey effort varies widely in the seasonal coverage, 

aerial coverage, and actual surveyed sites. Surveys have not been conducted consistently 

throughout time, or have even been dropped entirely as the result of wars, political 

turmoil, funding vagaries, etc. The methods vary in assessing total numbers of nests and 

total numbers of females. Many sea turtle scientists agree that the Guianas (and some 

would include Trinidad) should be viewed as one population and that a synoptic 

evaluation of nesting at all beaches in the region is necessary to develop a true picture of 

population status (Reichart et al. 2001). No such region-wide assessment has been 

conducted recently. 

The most recent, complete estimates of regional leatherback populations are in Spotila et 

al. (1996). As discussed above, nesting in the Guianas may have been declining in the 

late 1990s but may have increased again in the early 2000s. Spotila et al. estimated that 

the leatherback population for the Atlantic basin, including all nesting beaches in the 

Americas, the Caribbean, and West Africa totaled approximately 27,600 nesting females, 

with an estimated range of 20,082-35,133. We believe that the current population 

probably still lies within this range, taking into account the reported nesting declines and 

increases and the uncertainty surrounding them. We therefore choose to rely on Spotila 

et al.’s (1996) published total Atlantic population estimates, rather than attempt to 

construct a new population estimate here, based on our interpretation of the various, 

confusing nesting reports from areas within the region. 

Threats

Zug and Parham (1996) pointed out that the main threat to leatherback populations in the 

Atlantic is the combination of fishery-related mortality (especially entanglement in gear 

and drowning in trawls) and the intense egg harvesting on the main nesting beaches. 

48
Other important ongoing threats to the population include pollution, loss of nesting 

habitat, and boat strikes. 

Of sea turtle species, leatherbacks seem to be the most vulnerable to entanglement in 

fishing gear. This susceptibility may be the result of their body type (large size, long 

pectoral flippers, and lack of a hard shell), their attraction to gelatinous organisms and 

algae that collect on buoys and buoy lines at or near the surface, possibly their method of 

locomotion, and perhaps their attraction to the lightsticks used to attract target species in 

longline fisheries. They are also susceptible to entanglement in gillnets and pot/trap lines 

(used in various fisheries) and capture in trawl gear (e.g., shrimp trawls). 

Leatherbacks are exposed to pelagic longline fisheries in many areas of their range. 

Unlike loggerhead turtle interactions with longline gear, leatherback turtles do not usually 

ingest longline bait. Instead, leatherbacks are foul hooked by longline gear (e.g., on the 

flipper or shoulder area) rather than getting mouth hooked or swallowing the hook 

(NMFS 2001). According to observer records, an estimated 6,363 leatherback sea turtles 

were caught by the U.S. Atlantic tuna and swordfish longline fisheries between 1992-

1999, of which 88 were released dead (NMFS 2001). The U.S. fleet accounts for only 5 

to 8 percent of the hooks fished in the Atlantic Ocean, and adding up the underrepresented observed takes of the other 23 countries that actively fish in the area would 

lead to annual take estimates of thousands of leatherbacks over different life stages. 

Basin-wide, Lewison et al. (2004) estimated that 30,000-60,000 leatherback sea turtle 

captures occurred in Atlantic pelagic longline fisheries in the year 2000 alone (note that 

multiple captures of the same individual are known to occur, so the actual number of 

individuals captured may not be as high). 

Leatherbacks are also susceptible to entanglement in the lines associated with trap/pot 

gear used in several fisheries. From 1990-2000, 92 entangled leatherbacks were reported 

from New York through Maine (Dwyer et al. 2002). Additional leatherbacks stranded 

wrapped in line of unknown origin or with evidence of a past entanglement (Dwyer et al. 

2002). Fixed gear fisheries in the mid-Atlantic have also contributed to leatherback 

entanglements. In North Carolina, two leatherback sea turtles were reported entangled in 

a crab pot buoy inside Hatteras Inlet (D. Fletcher, pers. comm. to S. Epperly in NMFS 

2001). A third leatherback was reported entangled in a crab pot buoy in Pamlico Sound 

near Ocracoke. This turtle was disentangled and released alive; however, lacerations on 

the front flippers from the lines were evident (D. Fletcher, pers. comm. to S. Epperly in 

NMFS SEFSC 2001). In the Southeast, leatherbacks are vulnerable to entanglement in 

Florida’s lobster pot and stone crab fisheries. In the U.S. Virgin Islands, where one of 

five leatherback strandings from 1982 to 1997 was due to entanglement (Boulon 2000), 

leatherbacks have been observed with their flippers wrapped in the line of West Indian 

fish traps (R. Boulon, pers. comm. to J. Braun-McNeill in NMFS SEFSC 2001). Because 

many entanglements of this typically pelagic species likely go unnoticed, entanglements 

in fishing gear may be much higher. 

Leatherback interactions with the southeast Atlantic shrimp fishery, which operates 

predominately from North Carolina through southeast Florida (NMFS 2002), have also 

49
been a common occurrence. Leatherbacks, which migrate north annually, are likely to 

encounter shrimp trawls working in the coastal waters off the Atlantic coast from Cape 

Canaveral, Florida, to the Virginia/North Carolina border. Leatherbacks also interact 

with the GOM shrimp fishery. For many years, TEDs required for use in these fisheries 

were less effective at excluding leatherbacks than the smaller, hard-shelled turtle species. 

To address this problem, on February 21, 2003, the NMFS issued a final rule to amend 

the TED regulations. Modifications to the design of TEDs are now required in order to 

exclude leatherbacks and large and sexually mature loggerhead and green turtles. 

Other trawl fisheries are also known to interact with leatherback sea turtles. In October 

2001, a Northeast Fisheries Science Center observer documented the take of a 

leatherback in a bottom otter trawl fishing for Loligo squid off of Delaware; TEDs are 

not required in this fishery. The winter trawl flounder fishery, which did not come under 

the revised TED regulations, may also interact with leatherback sea turtles. 

Gillnet fisheries operating in the nearshore waters of the mid-Atlantic states are also suspected of 

capturing, injuring, and/or killing leatherbacks when these fisheries and leatherbacks co-occur. 

Data collected by the NEFSC Fisheries Observer Program from 1994 through 1998 (excluding 

1997) indicate that a total of 37 leatherbacks were incidentally captured (16 lethally) in drift 

gillnets set in offshore waters from Maine to Florida during this period. Observer coverage for 

this period ranged from 54 to 92 percent. 

Poaching is not known to be a problem for nesting populations in the continental U.S. 

However, in 2001 the NMFS Southeast Fishery Science Center (SEFSC) noted that 

poaching of juveniles and adults was still occurring in the U.S. Virgin Islands and the 

Guianas. In all, four of the five strandings in St. Croix were the result of poaching 

(Boulon 2000). A few cases of fishermen poaching leatherbacks have been reported from 

Puerto Rico, but most of the poaching is on eggs. 

Leatherback sea turtles may be more susceptible to marine debris ingestion than other 

species due to their pelagic existence and the tendency of floating debris to concentrate in 

convergence zones that adults and juveniles use for feeding areas and migratory routes 

(Lutcavage et al. 1997, Shoop and Kenney 1992). Investigations of the stomach contents 

of leatherback sea turtles revealed that a substantial percentage (44 percent of the 16 

cases examined) contained plastic (Mrosovsky 1981). Along the coast of Peru, intestinal 

contents of 19 of 140 (13 percent) leatherback carcasses were found to contain plastic 

bags and film (Fritts 1982). The presence of plastic debris in the digestive tract suggests 

that leatherbacks might not be able to distinguish between prey items and plastic debris 

(Mrosovsky 1981). Balazs (1985) speculated that the object might resemble a food item 

by its shape, color, size or even movement as it drifts about, and induce a feeding 

response in leatherbacks. 

It is important to note that, like marine debris, fishing gear interactions and poaching are 

problems for leatherbacks throughout their range. Entanglements are common in 

Canadian waters where Goff and Lien (1988) reported that 14 of 20 leatherbacks 

encountered off the coast of Newfoundland/Labrador were entangled in fishing gear 

50
including salmon net, herring net, gillnet, trawl line and crab pot line. Leatherbacks are 

reported taken by many other nations that participate in Atlantic pelagic longline 

fisheries, including Taipei, Brazil, Trinidad, Morocco, Cyprus, Venezuela, Korea, 

Mexico, Cuba, U.K., Bermuda, People’s Republic of China, Grenada, Canada, Belize, 

France, and Ireland (see NMFS SEFSC 2001, for a description of take records). 

Leatherbacks are known to drown in fish nets set in coastal waters of Sao Tome, West 

Africa (Castroviejo et al. 1994, Graff 1995). Gillnets are one of the suspected causes for 

the decline in the leatherback sea turtle population in French Guiana (Chevalier et al. 

1999), and gillnets targeting green and hawksbill turtles in the waters of coastal 

Nicaragua also incidentally catch leatherback turtles (Lagueux et al. 1998). Observers on 

shrimp trawlers operating in the northeastern region of Venezuela documented the 

capture of six leatherbacks from 13,600 trawls (Marcano and Alio-M 2000). An 

estimated 1,000 mature female leatherback sea turtles are caught annually in fishing nets 

off of Trinidad and Tobago with mortality estimated to be between 50 to 95 percent 

(Eckert and Lien 1999). However, many of the turtles do not die as a result of drowning, 

but rather because the fishermen butcher them in order to get them out of their nets 

(NMFS 2001). 

5.4.3 Summary of Leatherback Status 

In the Pacific Ocean, the abundance of leatherback turtle nesting individuals and colonies 

has declined dramatically over the past 10 to 20 years. Nesting colonies throughout the 

eastern and western Pacific Ocean have been reduced to a fraction of their former 

abundance by the combined effects of human activities that have reduced the number of 

nesting females. In addition, egg poaching has reduced the reproductive success of the 

remaining nesting females. At current rates of decline, leatherback turtles in the Pacific 

basin are a critically endangered species with a low probability of surviving and 

recovering in the wild. 

In the Atlantic Ocean, our understanding of the status and trends of leatherback turtles is 

much more confounded, although the picture does not appear nearly as bleak as in the 

Pacific. The number of female leatherbacks reported at some nesting sites in the Atlantic 

Ocean has increased, while at others they have decreased. Some of the same factors that 

led to precipitous declines of leatherbacks in the Pacific also affect leatherbacks in the 

Atlantic: leatherbacks are captured and killed in many kinds of fishing gear and interact 

with fisheries in state, federal, and international waters. Poaching is a problem and 

affects leatherbacks that occur in U.S. waters. Leatherbacks also appear to be more 

susceptible to death or injury from ingesting marine debris than other turtle species. 

5.5 Sperm Whale

Distribution 

The sperm whale is the largest of the toothed whales, reaching a length of 18.3 meters in 

males and 12.2 meters in females (Odell 1992). Sperm whales are distributed in all of the 

world's seas and oceans. For the purposes of management, the International Whaling 

Commission (IWC) defines four stocks: the North Pacific, the North Atlantic, the 

Northern Indian Ocean, and Southern Hemisphere. However, Dufault et al.'s (1999) 

51
review of the current knowledge of sperm whales indicates no clear picture of the 

worldwide stock structure of sperm whales. 

In general, females and immature sperm whales appear to be restricted in range, whereas 

males are found over a wider range and appear to make occasional movements across and 

between ocean basins (Dufault et al. 1999). Females and juveniles form pods that are 

generally within tropical and temperate latitudes between 50°N and 50°S, while the 

solitary adult males can be found at higher latitudes between 75o

N and 75oS (Reeves and 

Whitehead 1997). The home ranges of individual females seem to span distances of 

approximately 1,000 km (Best 1979, Dufault and Whitehead 1995). However, 

occasionally females travel several thousand kilometers across large parts of an ocean 

basin (Kasuya and Miyashita 1988). In the western North Atlantic they range from 

Greenland to the GOM and the Caribbean. 

Sperm whales generally occur in waters greater than 180 meters in depth. While they 

may be encountered almost anywhere on the high seas, their distribution shows a 

preference for continental margins, sea mounts, and areas of upwelling, where food is 

abundant. Waring et al. (1993) suggest sperm whale distribution in the Atlantic is closely 

correlated with the Gulf Stream edge. Bull sperm whales migrate much farther poleward 

than the cows, calves, and young males. Because most of the breeding herds are confined 

almost exclusively to warmer waters, many of the larger mature males return in the 

winter to the lower latitudes to breed. 

Life history 

Female sperm whales attain sexual maturity at the mean age of 8 or 9 years and a length 

of about 9 m (Kasuya 1991, see Würsig et al. 2000). The mature females ovulate April 

through August in the Northern Hemisphere. During this season one or more large 

mature bulls temporarily join each breeding school. A single calf is born at a length of 

about 4 m, after a 15 to 16 month gestation period. Sperm whales exhibit alloparental 

(the assistance by individuals other than the parents in the care of offspring) guarding of 

young at the surface (Whitehead 1996), and alloparental nursing (Reeves and Whitehead 

1997). Calves are nursed for 2 to 3 years (in some cases, up to 13 years); and the calving 

interval is estimated to be about 4 to 7 years (Kasuya 1991, see Würsig et al. 2000). 

Males have a prolonged puberty and attain sexual maturity at between age 12 and 20, and 

a body length of 12 m, but may require another 10 years to become large enough to 

successfully compete for breeding rights (Kasuya 1991, see Würsig et al. 2000). 

Bachelor schools consist of maturing males who leave the breeding school and aggregate 

in loose groups of about 40 animals. As the males grow older they separate from the 

bachelor schools and remain solitary most of the year (Best 1979). 

The age distribution of the sperm whale population is unknown, but they are believed to 

live at least 60 years. Potential sources of natural mortality in sperm whales include 

killer whales and the papilloma virus (Lambertsen et al. 1987). 

52
Cephalopods (i.e., squid, octopi, cuttlefishes, and nautili) are the main dietary component 

of sperm whales. The ommastrephids, onychoteuthids, cranchids, and enoploteuthids are 

the cephalopod families that are numerically important in the diet of sperm whales in the 

GOM (Davis et al. 2002). Other populations are known to also take significant quantities 

of large demersal and mesopelagic sharks, skates, and bony fishes, especially mature 

males in higher latitudes (Clarke 1962, 1979). Postulated feeding and hunting methods 

include lying suspended and relatively motionless near the ocean floor and ambushing 

prey; attracting squid and other prey with bioluminescent mouths; or stunning prey with 

ultrasonic sounds (Norris and Mohl 1983, and Berzin 1971, as cited in Würsig et al. 

2000). Sperm whales occasionally drown after becoming entangled in deep-sea cables 

that wrap around their lower jaw, and non-food objects have been found in their 

stomachs, suggesting these animals may at times cruise the ocean floor with open mouths 

(Würsig et al. 2000, Rice 1989). 

Diving and social behavior 

Sperm whales are noted for their ability to make prolonged, deep dives, and are likely the 

deepest and longest diving mammal. Typical foraging dives last 40 minutes and descend 

to about 400 m, followed by approximately 8 minutes of resting at the surface (Gordon 

1987, Papastavrou et al. 1989). However, dives of over 2 hours and deeper than 3.3 km 

have been recorded (Clarke 1976) and individuals may spend extended periods of time at 

the surface to recover. Descent rates recorded from echo-sounders were approximately 

1.7 m/sec and nearly vertical (Goold and Jones 1995). There are no data on diurnal 

differences in dive depths in sperm whales. Dive depth may be dependent upon temporal 

variations in prey abundance. 

Vocalizations and hearing 

Evidence suggests that the disproportionately large head of the sperm whale is an 

adaptation to produce acoustic signals (Norris and Harvey 1972, Cranford 1992). This 

suggests that vocalizations are extremely important to sperm whales. The function of 

vocalizations is relatively well-studied (Weilgart and Whitehead 1997, Goold and Jones 

1995). Long series of monotonous, regularly spaced clicks are associated with feeding 

and are thought to be produced for echolocation. Sperm whales also utilize unique 

stereotyped click sequence "codas" (Mullins et al. 1988, Watkins 1977, Adler-Fenchel 

1980, Watkins et al. 1985), according to Weilgart and Whitehead (1988) to possibly 

convey information about the age, sex, and reproductive status of the sender. Groups of 

closely related females and their offspring have group-specific dialects (Weilgart and 

Whitehead 1997). 

Population status and trend 

The primary factor for the population decline that precipitated ESA listing was 

commercial whaling in the 18th, 19th, and 20th centuries for ambergris and spermaceti. 

The IWC estimates that nearly a quarter-million sperm whales were killed worldwide in 

whaling activities between 1800 and 1900. From 1910 to 1982, there were nearly 

700,000 sperm whales killed worldwide from whaling activities (IWC Statistics 1959-

1983). Sperm whales have been protected from commercial harvest by the IWC since 

1981, although the Japanese continued to harvest sperm whales in the North Pacific until 

53
1988 (Reeves and Whitehead 1997). Since the ban on nearly all hunting of sperm 

whales, there has been little evidence that direct effects of anthropogenic causes of 

mortality or injury are significantly affecting the recovery of sperm whale stocks (Perry 

et al. 1999, Waring et al. 2002), yet the effects of these activities on the behavior of 

sperm whales has just recently begun to be studied. Presently, the global population of 

sperm whales is estimated to be at 32 percent of its pre-whaling number (Whitehead 

2002). 

Impacts of human activities 

Documented takes of sperm whales primarily involve offshore fisheries such as the 

offshore lobster pot fishery and pelagic driftnet and longline fisheries. Sperm whales 

have learned to depredate sablefish from longline gear in the Gulf of Alaska and toothfish 

from longline operations in the South Atlantic Ocean. No direct injury or mortality has 

been recorded during hauling operations, but lines have had to be cut when whales were 

caught on them (Ashford et al. 1996). Because of their generally more offshore 

distribution and their benthic feeding habits, sperm whales are less subject to 

entanglement than are right or humpback whales. Sperm whales have been taken in the 

pelagic drift gillnet fishery for swordfish, and could likewise be taken in the shark drift 

gillnet fishery on occasions when they may occur more nearshore, although this likely 

does not occur often. Although no interaction between sperm whales and the longline 

fishery have been recorded in the U.S. Atlantic, as noted above, such interactions have 

been documented elsewhere. The Southeast U.S. Marine Mammal Stranding Network 

received reports of 16 sperm whales that stranded along the GOM coastline from 1987 to 

2001 in areas ranging from Pinellas County, Florida to Matagorda County, Texas. One 

of these whales had deep, parallel cuts posterior to the dorsal ridge that were believed to 

be caused by the propeller of a large vessel; this trauma was assumed to be the proximate 

cause of the stranding. Due to the offshore distribution of this species, interactions that 

do occur are less likely to be reported than those involving right, humpback, and fin 

whales occurring in nearshore areas.

5.6 Gulf Sturgeon 

NMS and the FWS listed the Gulf sturgeon, also known as the GOM sturgeon, as a 

threatened species on September 30, 1991 (56 CFR 49653). The present range of the 

Gulf sturgeon extends from Lake Pontchartrain and the Pearl River system in Louisiana 

and Mississippi east to the Suwannee River in Florida. Sporadic occurrences have been 

recorded as far west as the Rio Grande River between Texas and Mexico, and as far east 

and south as Florida Bay (Wooley and Crateau 1985, Reynolds 1993). 

 

Life history

The Gulf sturgeon is an anadromous fish; adults spawn in freshwater then migrate to feed 

and grow in estuarine/marine habitats. After spawning in the upper river reaches, both 

adult and subadult Gulf sturgeon migrate from the estuaries, bays, and the GOM to the 

coastal rivers in early spring (i.e., March through May) when river water temperatures 

range from 16 to 23oC (Huff 1975, Carr 1983, Wooley and Crateau 1985, Odenkirk 1989, 

Clugston et al. 1995, Foster and Clugston 1997, Fox and Hightower 1998, Sulak and 

Clugston 1999, Fox et al. 2000). Fall downstream migration from the river into the 

54
estuary/GOM begins in September (at water temperatures around 23oC) and continues 

through November (Huff 1975, Wooley and Crateau 1985, Foster and Clugston 1997). 

 

Most subadult and adult Gulf sturgeon spend cool months (October or November through 

March or April) in estuarine areas, bays, or in the GOM (Odenkirk 1989, Foster 1993, 

Clugston et al. 1995, and Fox et al. 2002). Research indicates that in the estuary/marine 

environment both subadult and adult Gulf sturgeon show a preference for sandy shoreline 

habitats with water depths less than 3.5 m and salinity less than 6.3 parts per thousand 

(Fox and Hightower 1998). The majority of tagged fish have been located in areas 

lacking seagrass (Fox et al. 2002), in shallow shoals 1.5 to 2.1 m and deep holes near 

passes (Craft et al. 2001), and in unvegetated, fine to medium-grain sand habitats, such as 

sandbars, and intertidal and subtidal energy zones (Menzel 1971, Abele and Kim 1986). 

These shifting, predominantly sandy, areas support a variety of potential prey items 

including estuarine crustaceans, small bivalve mollusks, ghost shrimp, small crabs, 

various polychaete worms, and lancelets (Menzel 1971, Abele and Kim 1986, AFS 1989, 

and M. Brim, USFWS pers. comm. 2002). 

 

Once subadult and adult Gulf sturgeon migrate from the river to the estuarine/marine 

environment, having spent at least 6 months in the river fasting, it is presumed that they 

immediately begin foraging. Upon exiting the rivers, Gulf sturgeon are found in high 

concentrations near their natal river mouths; these lakes and bays at the mouth of the 

river are important because they offer the first opportunity for Gulf sturgeon to forage. 

Specifics regarding Gulf sturgeon diet items and foraging are discussed within Section IV 

(Effects of the Action) of this biological opinion. 

Gulf sturgeon are long-lived, with some individuals reaching at least 42 years in age 

(Huff 1975). Age at sexual maturity for females ranges from 8 to 17 years, and for males 

from 7 to 21 years (Huff 1975). Chapman et al. (1993) estimated that mature female Gulf 

sturgeon weighing between 29 and 51 kg produce an average of 400,000 eggs. 

Based on the fact that male Gulf sturgeon are capable of annual spawning, and females 

require more than one year between spawning events (Huff 1975, Fox et al. 2000), we 

assume that the Gulf sturgeon are similar to Atlantic sturgeon (A. o. oxyrhinchus); that is, 

they exhibit a long inter-spawning period, with females spawning at intervals ranging 

from every 3 to 5 years, and males every 1 to 5 years (Smith 1985). Spawning occurs in 

the upper river reaches in the spring when water temperature is around 15o

 to 20oC. 

While Sulak and Clugston (1999) suggested that sturgeon spawning activity is related to 

moon phase, other researchers have found little evidence of spawning associated with 

lunar cycles (Slack et al. 1999, Fox et al. 2000). Fertilization is external; females 

deposit their eggs on the river bottom and males fertilize them. Gulf sturgeon eggs are 

demersal, adhesive, and vary in color from gray to brown to black (Vladykov and 

Greeley 1963, Huff 1975, Parauka et al. 1991). 

 

Genetic studies conclude that Gulf sturgeon exhibit river-specific fidelity. Stabile et al. 

(1996) analyzed tissue taken from Gulf sturgeon in eight drainages along the GOM for 

genetic diversity; they noted significant differences among Gulf sturgeon stocks, and 

55
suggested region-specific affinities and likely river-specific fidelity. Five regional or 

river-specific stocks (from west to east) have been identified: (1) Lake Pontchartrain and 

Pearl River, (2) Pascagoula River, (3) Escambia and Yellow Rivers, (4) Choctawhatchee 

River, and (5) Apalachicola, Ochlockonee, and Suwannee Rivers (Stabile et al. 1996). 

Tagging studies also indicate that Gulf sturgeon exhibit a high degree of river fidelity 

(Carr 1983). Of 4,100 fish tagged, 21 percent (860/4100 fish) were later recaptured in the 

river of their initial collection, eight fish (0.009 percent) moved between river systems, 

and the remaining fish (78 percent) have not yet been recaptured (USFWS et al. 1995). 

There is no information documenting the presence of spawning adults in non-natal rivers. 

However, there is some evidence of inter-riverine (from natal rivers into non-natal) 

movements by both male and female Gulf sturgeon (n=22) (Wooley and Crateau 1985, 

Carr et al. 1996, Craft et al. 2001, Ross et al. 2001b, Fox et al. 2002). It is important to 

note that gene flow is low in Gulf sturgeon stocks, with each stock exchanging less than 

one mature female per generation (Waldman and Wirgin 1998). 

 

A full discussion of the life history of this subspecies may be found in the September 30, 

1991, final rule listing the Gulf sturgeon as a threatened species (56 FR 49653), the 

Recovery/Management Plan approved by NMFS and the U.S. Fish and Wildlife Service 

in September 1995, and the final rule designating Gulf sturgeon critical habitat (68 FR 

13370). 

Population dynamics and status

Gulf sturgeon occur in most major tributaries of the northeastern GOM, from the 

Mississippi River east to Florida’s Suwannee River, and in the central and eastern 

nearshore Gulf waters as far south as Charlotte Harbor (Wooley and Crateau 1985). In 

Florida, Gulf sturgeon are present in the Escambia, Yellow, Blackwater, 

Choctawhatchee, Apalachicola, Ochlockonee, and Suwannee Rivers (Reynolds 1993). 

While little is known about the abundance of Gulf sturgeon throughout most of its range, 

population estimates have been calculated for the Apalachicola, Choctawhatchee, and 

Suwannee Rivers. The USFWS calculated an average (from 1984-1993) of 115 

individuals (> 45 cm TL) over-summering in the Apalachicola River below Jim 

Woodruff Lock and Dam (USFWS et al. 1995). Preliminary estimates of the Gulf 

sturgeon subpopulation in the Choctawhatchee River system are 2,000 to 3,000 fish over 

61 cm TL. The Suwannee River Gulf sturgeon population (i.e., fish > 60 cm TL and 

older than age 2) has recently been calculated at approximately 7,650 individuals (Sulak 

and Clugston 1999). Although the size of the Suwannee River population is considered 

stable, the population structure is highly dynamic as indicated by length frequency 

histograms (Sulak and Clugston 1999). Strong and weak year classes coupled with the 

regular removal of larger fish (by natural mortality) limits the growth of the Suwannee 

River population but stabilizes the average population size (Sulak and Clugston 1999). 

6 ENVIRONMENTAL BASELINE 

This section contains a description of the effects of past and ongoing human activities 

leading to the current status of the species, their habitat, and the ecosystem, within the 

56
action area. The environmental baseline is a snapshot of the factors affecting the species 

and includes federal, state, tribal, local, and private actions already affecting the species, 

or that will occur contemporaneously with the consultation in progress. Unrelated, future 

federal actions affecting the same species that have completed formal or informal 

consultation are also part of the environmental baseline, as are implemented and ongoing 

federal and other actions within the action area that may benefit listed species. 

6.1 Status of Listed Species in the Action Area 

Sea turtles found in the action area may travel widely throughout the Atlantic, GOM, and 

Caribbean Sea; therefore, individuals found in the action area can potentially be affected 

by activities anywhere within this wide range. 

Leatherback Sea Turtle 

The leatherback is the most abundant sea turtle in waters over the northern GOM 

continental slope (Mullin and Hoggard 2000). Leatherbacks appear to spatially use both 

continental shelf and slope habitats in the GOM (Fritts et al. 1983, Collard 1990), but 

primarily utilize pelagic waters >200 m (Davis and Fargion 1996) throughout the 

northern GOM. Recent surveys suggest that the region from the Mississippi Canyon to 

DeSoto Canyon, especially near the shelf edge, appears to be an important habitat for 

leatherbacks (Mullin and Hoggard 2000). Surveys of sea turtles in the eastern GOM 

reported densities of 0.0026 individuals/km2

 (95 percent CI = 0.0004 - 0.0140) in 0-10 

fathoms and 0.0029 individuals/km2 (95 percent CI = 0.0015 - 0.0057) in 10-40 fathoms 

(Epperly et al. 2002). Leatherbacks are year-round inhabitants in the GOM with frequent 

sightings during both summer and winter (Mullin and Hoggard 2000). Temporal 

variability and abundance suggest that specific areas may be important to this species, 

either seasonally or for short periods of time. 

Green Sea Turtle 

Green sea turtles are found throughout the GOM. They occur in small numbers over 

seagrass beds along the south Texas and the Florida GOM coasts. Areas known as 

important feeding areas include the Homosassa River, Crystal River, and Cedar Key, 

Florida, and seagrass meadows and algae-laden jetties along the Texas coast. Sea turtle 

surveys in the eastern GOM have reported densities of 0.0021 individuals/km2 (95 

percent CI = 0.0006 - 0.0075) in 0-10 fathoms and 0.0137 individuals/km2

 (95 percent CI 

= 0.0060 - 0.0317) in 10-40 fathoms (Epperly et al. 2002). 

Kemp=s Ridley Sea Turtle 

The nearshore waters of the GOM are believed to provide important developmental 

habitat for juvenile Kemp's ridley sea turtles. Ogren (1988) suggests that the GOM coast, 

from Port Aransas, Texas, through Cedar Key, Florida, represents the primary habitat for 

subadult ridleys in the northern GOM. This species generally remains within the 50-m 

isobath of coastal areas throughout the GOM (Renaud 2001). Surveys of sea turtles in 

the eastern GOM reported densities of 0.0079 individuals/km2

 (95 percent CI = 0.0030 - 

0.0207) in 0-10 fathoms and 0.0011 individuals/km2

 (95 percent CI = 0.0004 - 0.0035) in 

10-40 fathoms (Epperly et al. 2002). Stomach contents from Kemp’s ridleys also 

indicate a nearshore distribution by their prey distribution which is consistent with other 

57
reported density estimates of 0.065 turtles per km2

 in 0-10 fathoms compared to a 

decrease of 0.013 turtles per km2

 in 10-40 fathoms (Epperly et al. 2002). 

 

Loggerhead Sea Turtle 

The nearshore waters of the GOM are believed to provide important developmental 

habitat for loggerhead sea turtles. Loggerhead nesting along the GOM coast occurs 

primarily along the Florida Panhandle, although some nesting has been reported from 

Texas through Alabama as well (NMFS and FWS 1991b). Surveys of sea turtles in the 

eastern GOM resulted in reported densities of 0.0532 individuals/km2

 (95 percent CI = 

0.0295 - 0.0961) in 0-10 fathoms and 0.0452 individuals/km2

 (95 percent CI = 0.0233 - 

0.0880) in 10-40 fathoms (Epperly et al. 2002). Loggerhead abundance does not appear 

to be significantly different between winter and summer months over shelf waters in the 

GOM (Davis et al. 2000a, 200b). Although loggerheads are widely distributed during 

both summer and winter, their abundance in surface waters over the continental slope 

may be greater during winter than in summer (Mullin and Hoggard 2000), and many 

sightings occurred near the 100-m isobath (Davis et al. 2000a, 200b). Sightings of 

loggerheads in waters over the continental slope suggest that they may be in transit 

through these waters to distant foraging sites or seeking warmer waters during the winter. 

The majority of sightings have occurred in waters over the continental shelf, although 

many sightings have been reported over the continental slope. 

In addition to some distribution over the slope waters, surface sightings of this species 

have also been made over the outer slope, approaching the 2,000-m isobath. 

Loggerheads found in deep waters may be traveling to distant nesting beaches, traveling 

between forage sites on distant and disjunct areas of the continental shelf, or seeking 

warmer waters during winter (Davis et al. 2000a, 200b). 

Sperm whale 

Sperm whale pods have been observed throughout the GOM from the upper continental 

slope near the 100-m isobath to the seaward extent of the United States EEZ and beyond, 

from sightings data collected from NOAA cruises from 1991 to 2000 (Roden and Mullin 

2000, Baumgartner et al. 2001, Burks et al. 2001). Based on NOAA surveys, 

opportunistic sightings, whaling catches, and stranding records, sperm whales in the 

GOM occur year-round. Sperm whales appear to favor water depths of about 1,000 m 

and appear to be concentrated in at least two geographic regions of the Northern GOM: 

an area off the Dry Tortugas and offshore of the Mississippi River delta (Maze-Foley and 

Mullin 2006); however, distribution also appears influenced by occurrence and 

movement of cyclonic/anti-cyclonic currents in the GOM. Davis et al. (2000a) noted the 

presence of a resident, breeding population of endangered sperm whales within 50 km of 

the Mississippi River Delta and suggested that this area may be essential habitat for 

sperm whales. The Southeast United States Marine Mammal Stranding Network 

received reports of 17 sperm whales that stranded along the GOM coastline from 1987 to 

2003 in areas ranging from Pinellas County, Florida, to Matagorda County, Texas. The 

GOM sperm whale abundance has most recently been estimated at 1,349 whales (CV = 

0.23) (Mullin and Fulling 2003), calculated from an average of estimates from surveys 

conducted between 1996 and 2001. 

58
The GOM stock is comprised of mostly females and calves, although large mature bulls 

have been recently sighted in the GOM. Based on seasonal aerial surveys, sperm whales 

are present in the northern GOM in all seasons, but sightings in the northern GOM are 

more common during the summer months (Davis et al. 2000a). Based on recent survey 

efforts, sperm whales concentrations are regularly sighted, and the boundaries of these 

areas of concentration in the Northern GOM appear to be approximately 86.5o

W to 

90.0o

W, north of 27.0oN (Mullin 2002), and off southern Florida in an area approximately 

86.5oW to 85.5oW, 24.0oN to 26.0oN (Mullin 2002); however, sperm whales have been 

reported throughout the GOM in waters greater than 200 m. 

Recent research on the genetic stock structure of GOM sperm whales, gender 

composition, and kinship patterns during 2000, 2001 and 2002 indicate a distinct 

matrilineal population structure of sperm whales in the GOM (Engelhaupt pers. comm. 

2003). In this study, 89 individuals (including satellite-tagged, D-tag tagged, 

opportunistic, and stranded whales) were genotyped using both mtDNA and 

microsatellite techniques and gender determined using molecular sexing techniques. The 

majority of whales sampled from groups throughout the north-central GOM fit the classic 

‘mixed’ group scenario, comprised of females and subadults of both sexes. A 

comparative analysis of matrilineal ntDNA and biparentally inherited nuclear genetic 

markers has begun to show population structure for these female lineages. Only four 

mtDNA haplotypes were found in the northern Gulf, with two being unique on a global 

scale to this geographic area. 

Gulf Sturgeon 

The Gulf sturgeon is found in the GOM primarily from Tampa Bay, Florida west to the 

mouth of the Mississippi River. The action area includes the entire geographic range of 

the species, all five genetically distinct Gulf sturgeon river-specific stocks, and winter 

habitat for all known (seven) reproducing riverine populations. 

Gulf sturgeon will be present in the project area from about September through May; they 

are not likely to be present in the project area in the summer (approximately May to 

September) when they are upstream at spawning areas. Upstream migration from the 

estuarine/marine area to riverine spawning areas occurs in early spring (i.e., March 

through May) when river water temperatures range from 16E to 23EC (Huff 1975, Carr 

1983, Wooley and Crateau 1985, Odenkirk 1989, Clugston et al. 1995, Foster and 

Clugston 1997, Fox and Hightower 1998, Sulak and Clugston 1999, Fox et al. 2000). 

Fall downstream migration from the river into the estuary/marine environment is cued by 

water temperature (around 23EC), generally beginning in September and continuing 

through November (Huff 1975, Wooley and Crateau 1985, Foster and Clugston 1997). 

Gulf sturgeon use the lower riverine, estuarine, and marine environment from about 

September through May for feeding and migration. Following a period of fasting in the 

river, the Gulf sturgeon are presumed to begin foraging as soon as they enter suitable 

brackish and marine habitat; they have been located in seagrass and sand in depths of 1.5 

to 5. 9 m (Fox and Hightower 1998, Craft et al. 2001, Parauka et al. in press) which 

supports a variety of potential prey items including estuarine crustaceans, small bivalve 

59
mollusks, and lancelets (Menzel 1971, Abele 1986, AFS 1989). In the estuarine/marine 

environment, Gulf sturgeon must consume sufficient prey to not only regain the body 

weight lost during the summer in the riverine environment, they must also obtain enough 

energy necessary for growth and reproduction (Fox et al. 2002, Murie and Parkyn pers. 

comm.). In addition to foraging, the Gulf sturgeon are migrating within the project area 

between habitats and, more rarely, between rivers. 

6.2 Federal Actions 

In recent years, NMFS has undertaken numerous ESA section 7 consultations to address 

the effects of federally-permitted fisheries and other federal actions on threatened and 

endangered listed species in the action area. Each of those consultations sought to 

develop ways of reducing the probability of adverse effects of the action on listed 

species. Similarly, recovery actions NMFS has undertaken under the ESA are addressing 

the problem of take of listed species in the fishing and shipping industries and other 

activities such as COE dredging operations. The summary below of anticipated sources 

of incidental take of listed species from federal actions includes only those actions which 

have already concluded or are currently undergoing formal section 7 consultation. 

Fisheries 

Adverse effects on threatened and endangered sea turtles from several types of fishing 

gear occur in the action area. These gears, including gillnet, hook-and-line (i.e., vertical 

line), and trawl gear have all been documented as interacting with sea turtles. For all 

fisheries for which there is a fishery management plan (FMP) or for which any federal 

action is taken to manage that fishery, the impacts have been evaluated via section 7 

consultation. Formal section 7 consultations have been conducted on the following 

fisheries: the HMS shark fishery and the southeast shrimp trawl fishery. An ITS has 

been issued for the take of sea turtles in each of the fisheries. A summary of each 

consultation is provided below but more detailed information can be found in the 

respective biological opinions (NMFS 2001b; NMFS 2002; NMFS 2003). 

The Southeast shrimp trawl fishery affects more sea turtles than all other activities 

combined (NRC 1990). NMFS completed the biological opinion (NMFS 2002a) for 

shrimp trawling in the southeastern United States under proposed revisions to the TED 

regulations (68 FR 8456, February 21, 2003). This biological opinion determined that the 

shrimp trawl fishery under the revised TED regulations would not jeopardize the 

continued existence of any sea turtle species. This determination was based, in part, on 

the biological opinion’s analysis that shows the revised TED regulations are expected to 

reduce shrimp trawl related mortality by 94 percent for loggerheads and 97 percent for 

leatherbacks. 

GOM shark fisheries include commercial shark bottom longline and drift gillnet fisheries 

and recreational shark fisheries under the FMP for Atlantic Tunas, Swordfish, and Sharks 

(HMS FMP). The shark bottom longline and drift gillnet fisheries were both found likely 

to adversely affect sea turtles. An ESA section 7 consultation was completed on October 

29, 2003, on the continued operation of those fisheries and the July 2003, Proposed Rule 

for Draft Amendment 1 to the HMS FMP (NMFS 2003a). The biological opinion 

60
concluded the proposed action was not likely to jeopardize the continued existence of any 

listed sea turtles. An ITS was provided authorizing non-lethal takes. 

On June 1, 2004, NMFS completed a biological opinion on the continued operation of the 

Atlantic HMS pelagic longline fishery and reef fish fishery in the Atlantic, GOM, and 

Caribbean under proposed rules changing gear and management measures to, among 

other things, require the use of only large circle hooks in the fishery. The biological 

opinion found that the continued prosecution of the pelagic longline fishery was likely to 

jeopardize the continued existence of leatherback sea turtles. However, NMFS 

implemented an RPA to allow for the continuation of the pelagic longline fishery without 

jeopardizing that species. The provisions of the RPA included measures to: (1) Reduce 

post-release mortality of leatherbacks; (2) improve monitoring of the effects of the 

fishery; (3) confirm the effectiveness of the hook and bait combinations that are required 

as part of the proposed action; and (4) take management action to avoid long-term 

elevations in leatherback takes or mortality. All other sea turtles were found not likely to 

be jeopardized. An ITS was provided. 

On February 12, 2005, NMFS issued a biological opinion (NMFS 2005c) on the 

continued authorization of reef fish fishing under the GOM reef fish fishery management 

plan (RFFMP) and proposed amendment 23. The fishery uses three basic types of gear: 

spear and powerhead, trap and hook-and-line gear. Hook-and-line gear used in the 

fishery includes both commercial bottom longline and commercial and recreational 

vertical line (e.g., handline, bandit gear, rod and reel). The biological opinion concluded 

that loggerhead, leatherback, hawksbill, green, and Kemp's ridley sea turtles may be 

adversely affected by operation of the fishery and an ITS was provided. However, the 

proposed action was not expected to jeopardize the continued existence of any of these 

species. 

Formal section 7 consultations have also been conducted for the issuance of several 

exempted fishing permits (EFP). These biological opinions have concluded the proposed 

activities may adversely affect but were not likely to jeopardize the continued existence 

of any sea turtles. ITSs for each EFP issued were provided. 

Vessel Operation 

Potential sources of adverse effects from federal vessel operations in the action area 

include operations of the U.S. Department of Defense (DOD), Navy (USN), Air Force 

and Coast Guard (USCG), the USEPA, NOAA, and the COE. The NMFS has conducted 

formal consultations with the USCG, the USN, and NOAA on their vessel operations. 

NMFS has also conducted section 7 consultations with vessel traffic related to energy 

projects in the GOM (MMS, FERC, and MARAD) to implement conservation measures. 

Through the section 7 process, where applicable, the NMFS has and will continue to 

establish conservation measures for all these agency vessel operations to avoid or 

minimize adverse effects to listed species. At the present time, however, they present the 

potential for some level of interaction. Private vessels participate in high-speed marine 

events concentrated in the southeastern United States and are a particular threat to sea 

turtles, and occasionally to marine mammals as well. The magnitude of these marine 

61
events is not currently known. NMFS and the USCG (who permit these events) are in 

consultation on these events, but a thorough analysis has not been completed. Refer to 

the biological opinions for the USCG (NMFS 1995; NMFS 1996; NMFS 1998) and the 

USN (NMFS 1997a) for detail on the scope of vessel operations for these agencies and 

conservation measures being implemented as standard operating procedures. 

Since the USN consultation only covered operations out of Mayport, Florida, potential 

still remains for USN vessels to adversely affect sea turtles when they are operating in 

other areas within the range of these species. Similarly, operations of vessels by other 

Federal agencies within the action area (NOAA, USEPA, COE) may adversely affect sea 

turtles. However, the in-water activities of those agencies are limited in scope, as they 

operate a limited number of vessels or are engaged in research/operational activities that 

are unlikely to contribute a large amount of risk. 

Military Operations 

The air space over the GOM is used extensively by the Department of Defense (DoD) for 

conducting various air-to-air and air-to-surface operations. Nine military warning areas 

and five water test areas are located within the GOM. The western GOM has four 

warning areas that are used for military operations. The areas total approximately 21 

million acres (ac) or 58% of the area. In addition, six blocks in the western GOM are 

used by the Navy for mine warfare testing and training. The central GOM has five 

designated military warning areas that are used for military operations. These areas total 

approximately 11.3 million ac. Portions of the Eglin Water Test Areas (EWTA) 

comprise an additional 0.5 million ac in the Central Planning Area (CPA). The total 11.8 

million ac is about 25% of the area of the CPA. 

NMFS has recently completed four consultation on Eglin Air Force Base testing and 

training activities in the GOM. These activities have not been found to adversely Gulf 

sturgeon or sperm whales, but have concluded that the incidental take of sea turtles in 

likely to occur. These biological opinion have issued incidental take for these actions: 

loggerheads, Kemp’s ridley, leatherback, and green sea turtles for the Eglin Gulf Test and 

Training Range (NMFS 2004c), the Precision Strike Weapons Tests (NMFS 2005a), and 

the Santa Rosa Island Mission Utilization Plan (NMFS 2005b); and loggerheads, a 

Kemp’s ridley, and a green sea turtle for the Naval Explosive Ordnance Disposal School 

(NMFS 2004d). The USN Mine Warfare Center in Corpus Christi, Texas, may take, 

annually, up to five loggerheads and two leatherbacks, hawksbills, greens, or Kemp’s 

ridleys, in combination, during training activities in the western GOM. Formal 

consultation on overall USCG or USN activities in the Gulf of Mexico has not been 

conducted. 

Dredging 

The construction and maintenance of Federal navigation channels has also been identified 

as a source of turtle mortality. Hopper dredges, which are frequently used in ocean bar 

channels and sometimes in harbor channels and offshore borrow areas, move relatively 

rapidly (compared to sea turtle swimming speeds) and can entrain and kill sea turtles, 

presumably as the drag arm of the moving dredge overtakes the slower moving turtle. A 

62
regional opinion for the COE’s Gulf of Mexico hopper dredging operations was 

completed in November 2003 (NMFS 2003b as last revised on January 9, 2007). The 

opinion concluded “no jeopardy” for sea turtles and Gulf sturgeon. An ITS was 

provided, as well as reasonable and prudent measures specified to minimize impacts 

included the use of temporal dredging windows, intake and overflow screening, the use 

of sea turtle deflector dragheads, observer and reporting requirements, and sea turtle 

relocation trawling. 

ESA Permits 

The ESA allows the issuance of permits to take ESA-listed species for the purposes of 

scientific research (section 10(a)(1)(a)). In addition, the ESA allows for the NMFS to 

enter into cooperative agreements with states developed under section 6 of the ESA, to 

assist in recovery actions of listed species. Prior to issuance of these authorizations, the 

proposal must be reviewed for compliance with section 7 of the ESA. 

Sea turtles are the focus of research activities authorized by a section 10 permit under the 

ESA. There are currently 11 active scientific research permits directed toward sea turtles 

that are applicable to the action area of this biological opinion. Authorized activities 

range from photographing, weighing, and tagging sea turtles incidentally taken in 

fisheries, blood sampling, tissue sampling (biopsy), and performing laparoscopy on 

intentionally captured turtles. The number of authorized takes varies widely depending 

on the research and species involved but may involve the taking of hundreds of turtles 

annually. Most takes authorized under these permits are expected to be non-lethal. 

Before any research permit is issued, the proposal must be reviewed under the permit 

regulations (i.e., must show a benefit to the species). In addition, since issuance of the 

permit is a federal activity, issuance of the permit by the NMFS must also be reviewed 

for compliance with section 7(a)(2) of the ESA to ensure that issuance of the permit does 

not result in jeopardy to the species. 

6.3 State or Private Actions 

Vessel Traffic

Commercial traffic and recreational pursuits can have an adverse effect on marine 

mammals and sea turtles by direct physical impacts from vessel strikes, or by interactions 

with boat propellers. 

State Fisheries 

Several coastal state fisheries are known to incidentally take listed species, but 

information on these fisheries is sparse (NMFS 2001a). Various fishing methods used in 

these commercial and recreational fisheries, including trawling, pot fisheries, gillnets, and 

vertical line are all known to incidentally take sea turtles, but information on these 

fisheries is sparse (NMFS 2001a). Although the past and current effects of state fisheries 

on listed species are currently not determinable, the NMFS believes that ongoing fishing 

activities in state water, may in part, be responsible for seasonally high levels of observed 

strandings of sea turtles on South Atlantic coastlines. Most state data are based on 

extremely low observer coverage or sea turtles were not part of data collection; thus, 

these data provide insight into gear interactions that could occur but are not indicative of 

63
the magnitude of the overall problem. The 2001 HMS biological opinion (NMFS 2001b) 

has an excellent summary of turtles taken in state fisheries through out the action area. 

To address data gaps, several state agencies have initiated observer programs to collect 

information on interactions between listed species and certain gear types. Other states 

have closed nearshore waters to gear-types known to have high encounter rates with 

listed species. Depending on the fishery in question, many state permit holders also hold 

federal permits; therefore, existing section 7 consultations on federal fisheries may 

address some of the state fishery impacts. NMFS is also actively participating in a 

cooperative effort with Atlantic States Marine Fisheries Commission to standardize 

and/or implement programs to collect information on level of effort and bycatch in state 

fisheries. 

Additional information on impact of take (i.e., associated mortality) is also needed for 

analysis of impacts to sea turtles from these fisheries. Certain gear types may have high 

levels of sea turtle takes, but very low rates of serious injury or mortality. For example, 

hook-and-line takes rarely are dead upon retrieval of gear, but trawls and gillnets 

frequently result in immediate mortality. Leatherbacks seem to be susceptible to a more 

restricted list of fisheries, while hardshell turtles, particularly loggerheads, seem to appear 

in data from almost all state fisheries. The HMS biological opinion also summarizes sea 

turtle interactions with flynets and various trawl techniques that occur within the action 

area. 

Louisiana, Mississippi, Alabama, and Florida have placed restrictions on gillnet fisheries 

within state waters such that very little commercial gillnetting takes place in southeast 

waters. 

Observations of state recreational fisheries have shown that loggerhead, leatherback, and 

green sea turtles are known to bite baited hooks, and loggerheads frequently ingest the 

hooks. Hooked turtles have been reported by the public fishing from boats, piers, and 

beach, banks, and jetties and from commercial fishermen fishing for reef fish and for 

sharks with both single rigs and bottom longlines (NMFS 2001b). A detailed summary 

of the known impacts of hook-and-line incidental captures to loggerhead sea turtles can 

be found in the TEWG reports (1998, 2000). 

Oil and Gas Activities 

State oil and gas exploration, production, and development are expected to result in 

similar effects to protected species as reported in the analysis of federal activities for oil 

and gas lease sale biological opinions with the MMS, including impacts associated with 

the explosive removal of offshore structures, seismic exploration, marine debris, oil 

spills, and vessel operation. 

6.4 Other Potential Sources of Impacts in the Environmental Baseline 

A number of activities that may indirectly affect listed species in the action area of this 

consultation include ocean dumping and disposal, aquaculture, and anthropogenic marine 

debris. The impacts from these activities are difficult to measure. Where possible, 

64
conservation actions are being implemented to monitor or study impacts from these 

sources. Close coordination is occurring through the section 7 process on both dredging 

and disposal sites to develop monitoring programs and ensure that vessel operators do not 

contribute to vessel-related impacts. 

Marine Pollution 

Sources of pollutants in the GOM coastal regions include atmospheric loading of 

pollutants such as PCBs, stormwater runoff from coastal towns, cities and villages, runoff 

into rivers emptying into the bays, groundwater and other discharges, and river input and 

runoff. Nutrient loading from land-based sources such as coastal community discharges 

is known to stimulate plankton blooms in closed or semi-closed estuarine systems. The 

effects on larger embayments are unknown. Although pathological effects of oil spills 

have been documented in laboratory studies of marine mammals and sea turtles (Vargo et 

al. 1986), the impacts of many other anthropogenic toxins have not been investigated. 

Acoustic Impacts 

NMFS has also been working to establish criteria to predict varying levels of responses of 

marine mammals to anthropogenic noise, based upon hearing injury and behavioral 

responses of marine mammals. Responses to noise exposure may include lethal or nonlethal injury, temporary hearing impairment, behavioral harassment and stress, or no 

apparent response. Ambient noise in the GOM is approximately 40 dB re 1 μPa above 

estimated baseline levels prior to industrialization, and it is expected to increase. 

Contributions to ambient noise levels include vessels; geophysical exploration; and the 

construction, operational, and decommissioning of offshore structures. It is expected that 

the policy on managing anthropogenic sound in the oceans will provide guidance for 

programs such as incidental harassment permits under the Marine Mammal Protection 

Act and permits for research involving sound-producing activities. NOAA is working 

cooperatively with the ship-building industry to find technologically-based solutions to 

reduce the amount of noise produced by commercial vessels. Through ESA consultation 

with NMFS, MMS has implemented GOM-wide measures to reduce the risk of 

harassment to sperm whales from noise produced by geological and geophysical 

surveying activities and the explosive removal of offshore structures. 

Hypoxia 

A large area of the Louisiana continental shelf with seasonally-depleted oxygen levels (< 

2mg/l) is caused by eutrophication from both point and non-point sources. Most aquatic 

species cannot survive at such low oxygen levels and these areas are known as “dead 

zones.” The oxygen depletion, referred to as hypoxia, begins in late spring, reaches a 

maximum in mid-summer, and disappears in the fall. After the Mississippi River flood of 

1993, the spatial extent of this zone more than doubled in size, to over 18,000 km2, and 

has remained about that size each year through mid-summer of 1997. The hypoxic zone 

has impacts on the animals found there, including sea turtles, and the ecosystem-level 

impacts continue to be investigated. 

65
Natural Seeps 

Naturally occurring hydrocarbon seepage has long been identified as a significant source 

of hydrocarbons. Tarballs coming from natural seeps were used by early indigenous man 

living along the GOM coast to construct hunting tools. Given that the GOM is a prolific 

petroleum-producing province, its seafloor is pocketed with areas from which oil and gas 

seep. Accurately calculating the volume of naturally seeping oil is problematic. Often 

the volume measured floating on the surface of the water or beached has been used as the 

best indicator of the volume originally seeped. 

6.5 Conservation and Recovery Actions Shaping the Environmental Baseline 

NMFS has implemented a series of regulations aimed at reducing potential for incidental 

mortality of sea turtles in commercial fisheries. In particular, NMFS has required the use 

of TEDs in southeast U.S. shrimp trawls since 1989 and in summer flounder trawls in the 

mid-Atlantic area (south of Cape Charles, Virginia) since 1992. It has been estimated 

that TEDs exclude 97 percent of the sea turtles caught in such trawls. These regulations 

have been refined over the years to ensure that TED effectiveness is maximized through 

proper placement and installation, configuration (e.g., width of bar spacing), floatation, 

and more widespread use. Analyses by Epperly and Teas (2002) indicated that the 

minimum requirements for the escape opening dimensions in TEDs in use at that time 

were too small, and that as many as 47 percent of the loggerheads stranding annually 

along the Atlantic Seaboard and GOM were too large to fit through existing openings. 

On February 21, 2003, NMFS published a final rule to require larger escape openings in 

TEDs used in the Southeast shrimp trawl fishery (68 FR 8456, February 21, 2003). 

Based upon the analyses in Epperly et al. (2002), leatherback and loggerhead sea turtles 

will greatly benefit from the new regulations, with expected reductions of 97 percent and 

94 percent, respectively, in mortality from shrimp trawling. Several states have 

regulations requiring the use of TEDs in state-regulated trawl fisheries, and the federal 

regulations also apply in state waters. 

NMFS has also been active in public outreach efforts to educate fishermen regarding sea 

turtle handling and resuscitation techniques. As well as making this information widely 

available to all fishermen, NMFS recently conducted a number of workshops with 

Atlantic HMS pelagic longline fishermen to discuss bycatch issues including protected 

species, and to educate them regarding handling and release guidelines. NMFS intends to 

continue these outreach efforts and hopes to reach all fishermen participating in the 

Atlantic HMS pelagic longline fishery over the next one to two years. There is also an 

extensive network of STSSN participants along the Atlantic and GOM coasts who not 

only collect data on dead sea turtles, but also rescue and rehabilitate any live stranded sea 

turtles. 

Loggerheads, leatherbacks, greens, and Kemp’s ridleys are known to bite a baited hook, 

frequently ingesting the hook. Hooked turtles have been reported by the public fishing 

from boats, piers, beaches, banks, and jetties. Necropsies have revealed hooks internally, 

which often were the cause of death. NMFS currently is exploring adding questions 

about encounters with sea turtles to intercept interviews of recreational fishermen 

conducted by the Texas Parks and Wildlife Department under the auspices of the Marine 

66
Recreational Fishery Statistics Surveys conducted throughout the GOM and along the 

Atlantic Coast as well as adding such information to the MRFSS database. NMFS is also 

considering questioning recreational fishermen aboard headboats throughout the 

southeast U.S. Atlantic and the GOM to quantify their encounters with sea turtles 

(TEWG 2000). Detailed summaries of the impact of hook-and-line incidental captures 

on loggerhead sea turtles can be found in the TEWG reports (1998, 2000). 

The Recovery Plans for loggerhead and Kemp’s ridley sea turtles are in the process of 

being updated. Recovery teams comprised of sea turtle experts have been convened and 

are currently working towards revising these plans based upon the latest and best 

available information. 

7 EFFECTS OF THE ACTION 

Regulations implementing section 7(a)(2) of the ESA requires biological opinions to 

evaluate the direct and indirect effects of federal actions to determine if it would be 

reasonable to expect them to appreciably reduce listed species' likelihood of surviving 

and recovering in the wild by reducing their reproduction, numbers, or distribution (16 

U.S.C. '1536; 50 CFR 402.02). Section 7 of the ESA also requires biological opinions to 

determine if federal actions would destroy or adversely modify designated critical habitat 

(16 U.S.C. '1536). 

In this section NMFS analyzes the adverse effects expected to occur as a result of the 

proposed five-year lease sale plan for the WPA and CPA. MMS actions will allow oil 

and gas operations to take place in association with the lease sales, with effects to the 

near-shore and offshore environments. A description of activities is provided in the 

Description of the Proposed Action section, and those effects that were considered, but 

determined to be insignificant or discountable appear in sections 3 and 4 of this biological 

opinion. The potential for Gulf sturgeon critical habitat to be adversely affected was 

considered in section 4.1. 

Approach to the Assessment 

The ESA requires biological opinions to include details of how the agency action affects 

listed species or their critical habitat along with the information that forms the basis of 

the biological opinion (16 U.S.C. 1536). Regulations that implement Section 7 of the 

ESA require biological opinions to include an evaluation of whether the action would be 

reasonably expected to appreciably reduce the likelihood of survival and recovery of 

listed species in the wild by reducing their reproduction, numbers, or distribution or 

would be reasonably expected to destroy or adversely modify critical habitat (50 CFR 

402.02). We approach the analysis by identifying the probable direct and indirect effects 

of an action on the environment of the action area. In the second step, we assess the risk 

to individual animals (of listed species) from exposure to such changes in the 

environment, taking into consideration any potential responses of the animals, and then 

conduct an analysis to determine if any expected changes result in jeopardy to those 

populations of listed species. 

67
7.1 Vessel Strikes 

Sea turtles may be accidentally injured or killed by collisions with vessels over the 40-

year life of operations resulting from the proposed action. As stated above, increased 

ship traffic could increase the probability of collisions between ships and sea turtles. 

Although there have been thousands of vessel trips that have been made in support of 

offshore operations during the past 40 years of OCS oil and gas operations, there have 

been no reports of OCS-related vessels having struck sea turtles. However, collisions 

with small and/or submerging turtles may go undetected, even with an observer onboard, 

and stranding records frequently document evidence of interactions such as cracked 

carapaces, missing limbs, and propeller cuts or scars. Sea turtles could, on occasion, be 

killed or injured by collisions with oil and gas service vessels. 

In the wild, most adult sea turtles spend at least 3-6 % of their time at the surface for 

respiration. Despite the brevity of their respiratory phases, sea turtles sometimes spend 

as much as 26 % of their time at the surface, engaged in surface basking, feeding, 

orientation, and mating (Lutcavage et al. 1997). Sea turtles located in shallower waters 

have shorter surface intervals, whereas turtles occurring in deeper waters have longer 

surface intervals. Data show that vessel traffic is one cause of sea turtle mortality in the 

GOM (Lutcavage et al. 1997). Stranding data for the U.S. GOM and Atlantic coasts 

show that vessel-related injuries were noted in 13 % of stranded turtles examined during 

1993 (Teas 1994), but this figure includes those that may have been struck by boats postmortem. In Florida, where there are a high number of recreational vessels, the frequency 

of boat injuries between 1991 and 1993 was 18% of strandings (Lutcavage et al. 1997). 

Data indicate that live- and dead-stranded sea turtles showing signs of vessel-related 

injuries continue in a high percentage of stranded sea turtles in coastal regions of the 

southeastern United States.

Based on active leases as of April 2006, 55 percent of those leases occur in water depths 

greater than 200 m (3,606 occur on water depths from 0-200 m; 4,501 occur in water 

depth greater than 200 m). Due to the uncertainties in the factors affecting interactions 

between vessels and sea turtles, the following assumptions have been made to calculate 

the encounter rates in Table 5: 

• sea turtle densities in Table 5; 

• an average offshore supply vessel measuring 70 m x 16 m (0.0700 km x 

0.0160 km); 

• 100 percent of the maximum number of annual vessel trips will occur in water 

depths <200 m (238,000 trips) 

• 55 percent of the maximum number of annual vessel trips will occur in water 

depths ≥200 m (130,900 trips); 

• a random distribution of vessels and sea turtles; 

• turtles are stationary at the surface; and 

• a vessel may affect a sea turtle once per round trip.

Based on the above assumptions, the dimensions of a vessel is a rectangular-shaped space 

occupying a potential impact area of 0.0011 km2

 for a single vessel, a maximum 

68
harassment area of 262 km2

 resulting from a total of 238,000 vessel trips annually in 

water depths <200 m, and an area of 144 km2

 resulting from 130,900 vessel trips 

annually in water depths ≥200 m. Based on sea turtle densities in the GOM, the greatest 

estimated annual encounter rates between vessels and sea turtles would be expected in 

water depths <200 m (Table 5). This estimate assumes a vessel is stationary; however, 

since vessels are underway between destinations, the probability for a randomly 

positioned, stationary sea turtle to be encountered may be expected to increase as a vessel 

moves through the water. The operating speeds and actual distances traveled by the 

annual number of vessel transits can be highly variable, and is therefore considered 

qualitatively in this analysis. 

Table 5. Sea turtle densities in the GOM and estimates of encounters between vessels 

and sea turtles. 

Species Density 

(individuals km-2)

Annual 

Encounters 

Encounters Over 

40 Years 

<200 ma

leatherback 0.0026 0.6812 27.25 

green 0.0142 3.7204 148.82 

Kemp=s ridley 0.0047 1.2314 49.26 

loggerhead 0.0443 11.6066 464.26 

hawksbill 0.0000 0.0000 0.00 

>200 mb

leatherback 0.0024 0.3456 13.82 

greenc 0.0005 0.0720 2.88 

Kemp=s ridleyc 0.0005 0.0720 2.88 

loggerhead 0.0020 0.2880 11.52 a

Density estimates are upper confidence limits of greatest reported density in water depths <200 m of the 

western GOM reported in Epperly et al. 2002. 

b

Density estimates from seasonal averages reported in Davis et al. 2000b. c

Unidentified chelonids from Davis et al. 2000b are assumed to be Kemp’s ridleys or greens sea turtles. 

Hawksbills are not expected to occur in deep water habitats are excluded from the >200 m analysis. 

Table 5 provides an estimate of potential encounter rates with sea turtles based on the 

probability that one sea turtle will occupy the same space as a vessel during each vessel 

trip. Although sea turtles are not randomly distributed and may be expected to occur in 

greater densities in some regions than others, we consider the assumptions reasonable to 

estimate the potential risk of vessels strikes with sea turtles on an annual basis. The 

distribution of sea turtles may be affected by a variety of biotic and abiotic factors, 

including season, water temperature, prey distribution, and life history stage. These 

factors may significantly affect where and when sea turtles may be encountered in the 

GOM. In reality, both sea turtles and vessels may have the opportunity to avoid one 

another and encounter rates may be highly variable. When underway vessels do come 

upon sea turtles, sea turtles may respond by swimming away at the surface or diving and 

vessels may take prudent actions to avoid striking an animal. Avoidance behavior by sea 

69
turtles is advantageous to avoid being struck, and avoidance behavior is expected to be 

insignificant on both the individual and the population; however, a few individuals would 

be expected to be at risk of injury or mortality over the lifetime of the action (Table 5).

To reduce the risk of potential injury and mortality resulting from vessel collisions with 

sea turtles, MMS will implement NMFS’ vessel strike avoidance measures for protected 

species, as implemented in MMS NTL 2007-G04. With implementation of these 

measures, by maintaining a lookout for sea turtles and taking prudent actions to avoid 

collisions with them, NMFS believes that the likelihood of collisions between vessels and 

sea turtles will be reduced. However, due to nighttime operation of vessels and the small 

size of sea turtles, some individuals may go unobserved and may be accidentally struck 

by an underway vessel. 

The following take estimates are based on the assumptions in the risk analysis conducted, 

and the following considerations. Although vessel operators are required to maintain a 

watch for and avoid sea turtles, NMFS estimates sightings will be reduced by 55 percent 

due to darkness, and reduced an additional 20 percent due to poor sea state and visibility, 

and other factors such as operator fatigue resulting in sea turtles going unobserved. The 

magnitude of the impact on vessel-struck sea turtles may range from minor annoyance to 

injury, or death, which is dependent on the speed of the vessel, depth of the turtle, and 

angle of impact. Due to the variable operational speeds and conditions under which 

animals may be struck, we estimate that 1/3 of vessels striking sea turtles will result in 

mortality. Based on the greatest encounter rate for each species calculated in Table 5, a 

detection and collision avoidance rate of 25%, and estimate that 1/3 of all strikes will be 

lethal the incidental take of each sea turtle species by vessel strike over 40-years of the 

proposed lease sales is calculate as follows: 

Number at 

Risk of Strike

Species Encounters Over 

40 Years 

Non-Lethal 

Take 

Lethal Take 

leatherback 41 31 21 10 

green 152 114 76 38 

Kemp=s ridley 52 39 26 13 

loggerhead 476 357 238 119 

hawksbill 3 2 1 1 

Numbers with decimal places >0.50 were rounded to the next nearest whole number. 

7.2 Geological and Geophysical Surveys 

NMFS has completed two biological opinions on seismic surveys occurring in the WPA 

and CPA of the GOM (NMFS 2002b and 2002c) and most recently for lease sales 

occurring in the Eastern Planning Area (NMFS 2003c) and are incorporated by reference 

in the following analysis. In these biological opinions we anticipated incidental takes of 

sperm whales, but an incidental take statement was not included for sperm whales since a 

take authorization has not yet been issued under Section 101(a) (5) of the MMPA. On 

December 26, 2002, the MMS submitted a request for 5-year regulations under the 

MMPA for the taking, by harassment, of sperm whales incidental to oil and gas 

70
industry’s seismic surveys to discover oil and gas deposits offshore in the GOM. NMFS 

published an Advance Notice of Proposed Rulemaking regarding the small take 

authorization on March 3, 2003 (68 FR 9991). Following issuance of such regulations 

under the MMPA, NMFS intends to estimate the number of potential takes of sperm 

whales and authorize any take that may be necessary. Seismic surveys associated with 

the proposed lease sales occur in deep, offshore waters of the OCS that is well outside the 

range of Gulf sturgeon; therefore, the effects of seismic surveys on this species are not 

considered further. 

7.2.1 Effects of Seismic Surveys on Sperm Whales 

The received sound level resulting in behavioral changes (and harassment) has not been 

measured in sperm whales, but do not expect the received level to be lower than that of 

baleen whales. Unlike baleen whales, sperm whales are not likely to be low-frequency 

specialists, but are believed to be most sensitive in the mid-frequency hearing range 

(Madsen et al. 2002). Low frequency sounds travel further distances than higher 

frequency sounds, resulting in a greater potential of disturbance for baleen whales. 

Previous biological opinions, herein incorporated by reference, have considered the 

potential for sperm whales to experience hearing loss, disturbance, habituation, 

sensitization, and masking with exposure to seismic surveys. There is no new 

information available from the date of those biological opinions that would alter the 

conclusions of those biological opinions and summarized below. The proposed action 

would result in multiple seismic surveys in the lease sale areas, which overlap with 

known habitat and presence of sperm whales. We believe that permanent hearing loss 

(permanent threshold shift or PTS) is unlikely to occur given that seismic survey 

operators would continue to implement the seismic minimization measures according to 

the MMS Notice to Lessees. Masking also would be unlikely to occur due to the 

characteristics of the airgun pulses. The primary concerns are with the potential for 

temporary hearing loss, important sperm whale behaviors to be disrupted, cow-calf pair 

disturbance, habituation to seismic pulses, and possible effects to their prey. Given that a 

seismic survey could be conducted over a broad area for weeks or months, a social group 

that remains in a particular location would be repeatedly exposed to airgun pulses at a 

variety of received levels. This exposure could result in repeated disruptions to a group 

that is caring for a calf or some reduction in feeding due to prey relocations or the 

disruption of a sperm whale’s hunt. Exposed sperm whales may also be subject to some 

level of stress that is not evident or observable through any changes in behavior. Though 

the available information indicates that some avoidance or disturbance from airgun noise 

is possible, the reported observations do not indicate that any immediate physical injury 

is occurring. Furthermore, seismic surveys have been conducted in the proposed lease 

sale area and other parts of the northern GOM, yet sperm whales continue to be present 

there and their population appears to be stable. If behavioral disruptions do occur during 

seismic surveys, we expect that the disruption would be limited to the duration of 

exposure to the noise, which may be highly variable. 

The nutritional status of females is linked to annual calf production in whales and other 

animals. A reduction in hearing ability, prey availability, or hunting success could likely 

71
affect milk production and nutritional status of lactating females, and depending on the 

level of disruption, calf production could possibly be reduced in any given year 

depending on the number and duration of seismic surveys. This further highlights the 

continued importance of implementation of MMS’s NTL No. 2007-G02. 

Summary of Effects on Sperm Whales 

In summary, sperm whales are expected to be harassed through disruption of important 

biological behaviors as a result of the use of airguns in seismic surveys associated with 

the proposed action and these behavioral responses are likely to result in a biological 

effect which may adversely affect sperm whales. However, the continued 

implementation of the impact minimization measures from seismic surveys in MMS’s 

NTL (APPENDIX A) is expected to reduce this harassment and to prevent this 

harassment from resulting in actual loss of individual sperm whales. 

7.3 Oil spills 

Offshore oil spills associated with a proposed action can result from platform accidents, 

pipeline breaks, or navigation accidents. Coastal oil spills can result from storage, barge, 

or pipeline accidents. The most likely locations of coastal spills are at pipeline terminals 

and other shore bases, oil spills have been described in the GOM (Bedinger et. al 1982, 

Van Vleet and Pauly 1987, Van Vleet et al. 1984). Spills from support vessels could 

occur from navigation accidents and will be largely confined in navigation channels and 

canals. Slicks may quickly spread through the channel by tidal, wind, and traffic (vessel) 

currents. The severity of the effects of an oil spill on listed species would be related to 

the location of the spill, the type of oil, the level of contact with the oil that the whales, 

turtles or fish have, and the life stage of the animal encountering the oil. 

The following analysis first considers the potential effects to sea turtles, Gulf sturgeon, 

and sperm whales from accidental oil spills, and then considers MMS’ oil spill risk 

analysis (OSRA). Using the results of the OSRA, the probable likelihood of oil spills 

occurring in each species habitat is determined. Oil spill trajectory simulations are 

generated by MMS to be used to estimate spill risk. The MMS uses a numerical 

computer model that simulates the likely trajectory of a surface slick, represented as a 

point launched from locations projected onto a gridded area. The point’s trajectory 

simulates a spill’s movement on the surface of water by using modeled ocean current and 

wind fields. The model uses temporally and spatially varying, numerically computed 

ocean currents and winds. Finally, the number of exposures to each species is estimated, 

and the potential for take resulting from those exposures is evaluated. 

7.3.1 Effects on Sea Turtles

Spilled oil could affect any life history stage or age class of sea turtles (Vargo et. al 

1986). Offshore and coastal spills could affect any species or age class of sea turtle 

coming into contact with a slick. Direct contact would continue to occur for as long as 

the slick persists, but physiological effects could continue for long periods once the slick 

diminishes. If a sea turtle were not directly exposed to a slick, hydrocarbons continue to 

persist in the sea for decades or longer. Tarballs are a byproduct of accidentally spilled 

oil, normal and accepted ship operations (e.g., bilge tank flushing), illegal discharges 

72
from tank washings, and natural oil seeps on the seafloor. They are found in every ocean 

and on every beach; features such as convergence zones and Langmuir cells can 

aggregate even widely dispersed tarballs into an area where sea turtles concentrate. 

USFWS biologists from Texas recently commented to MMS that they are still finding 

tarballs, probably from the Ixtoc oil spill in Mexico that occurred decades ago, washing 

up on Padre Island National Seashore. Tarballs ingested by any age class of sea turtle are 

likely to have a variety of effects, including starvation from gut blockage, decreased 

absorption efficiency, absorption of toxins, effects of general intestinal blockage (such as 

local necrosis or ulceration), interference with fat metabolism, and buoyancy problems 

caused by the buildup of fermentation gases (floating prevents turtles from feeding and 

increases their vulnerability to predators and boats), among others. 

Effects of Oil on Sea Turtle Nesting 

Spilled oil reaching a sea turtle nesting beach could have affects on nesting sea turtles 

and egg development. An oiled beach could affect nest site selection or result in no 

nesting at all (e.g., false crawls). A nesting sea turtle crawling up a beach could result in 

external oiling of the skin and carapace. Upon successful nesting, some indirect effects 

of beach oiling could result in changed sex ratios on a nesting beach. Hays et al. (2001) 

determined that subtle differences in sand color or albedo can significantly affect 

underlying temperatures. Because sex determination in turtles is temperature-dependent, 

shifts in albedo could potentially change hatchling sex ratios. Even light surface oiling 

that does not penetrate directly to the eggs could therefore affect gender distribution in a 

population. To simulate heavier beach oiling, Fritts and McGehee (1982) conducted 

laboratory studies by exposing eggs to fresh oil during the last half to last quarter of the 

incubation period. Oil-exposed eggs showed a significant lower rate of egg survival, than 

eggs that were not exposed to oil. Weathered oil appeared to lose its toxic effect on eggs 

and it was concluded that oil spilled even a few weeks prior to the nesting season would 

have little effect on successful egg development. 

Effects of Oil on Hatchlings 

Upon hatching and successfully reaching the water, hatchlings are subject to the same 

types of oil spill exposure hazards as adults. Hatchlings that contact oil residues while 

crossing a beach can exhibit a range of effects, from acute toxicity to impaired movement 

and normal bodily functions. However, differences in size and behavior increase the risk 

of oils spills on hatchlings. Most reports of oiled hatchlings originate from convergence 

zones, ocean areas where currents meet to form collection points for material at or near 

the surface of the water. These zones aggregate oil slicks as well as smaller, weaker sea 

turtles. Because hatchlings spend a greater proportion of their time at the surface than 

adults, their risk of exposure to floating oil slicks would be increased. 

In convergence zones off the east coast of Florida, tar was found in the mouths, esophagi, 

or stomachs of 65 out of 103 post-hatchling loggerheads (Loehefener et al. 1989). In 

another study (Witherington 1994), 34 percent of post-hatchlings at “weed lines” off the 

Florida coast had tar in their mouths or esophagi, and over half had tar caked in their 

jaws. Lutz (1989) reported that hatchlings have been found apparently starved to death, 

their beaks and esophagi blocked with tarballs. Hatchlings sticky with oil residue may 

73
have a more difficult time crawling and swimming, rendering them more vulnerable to 

predation. 

Effects of Oil on Sea Turtle Juveniles and Adults 

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al. 1995) 

suggest that sea turtles show no avoidance behavior when they encounter an oil slick and 

any sea turtle in an affected area would be expected to be exposed. Sea turtles’ diving 

behaviors also puts them at risk. Sea turtles rapidly inhale a large volume of air before 

diving and continually resurface over time that may result in repeated exposure to volatile 

vapors and oiling. 

Lutcavage et al. (1995) studies provided qualitative evidence that oil exposure disrupted 

lachrymal gland (salt gland) function, in which the glands physiologically did not 

function for several days. Experiments on physiological and clinicopathological effects 

of oil on loggerhead sea turtles approximately 15 to 18 months old showed that the 

turtles’ major physiological systems are adversely affected by both chronic and acute 

exposures (96-hour exposure to a 0.05-cm layer of South Louisiana crude oil versus 0.5 

cm for 48 hours). The skin of exposed turtles, particularly the soft pliable areas of the 

neck and flippers, sloughed off in layers for up to 2 weeks and recovery taking up to 3 

weeks. Oil was also detected in the nares, eyes, upper esophagus, and feces, indicating 

that turtles were ingesting oil, though apparently not enough to cause intestinal bleeding 

and anemia. Internal effects of oil exposure also include significant changes in blood and 

blood chemistry. Hematocrits (red blood cell volume) decreased nearly 50 percent in 

oiled turtles and did not increase again during the recovery period. An immune response 

indicated by significant increases in white blood cells lasted more than a week in sea 

turtles exposed to oil. 

Turtles also indiscriminately eat anything that registers as being an appropriate size for 

food, including tarballs. Oil ingested by a turtle does not pass rapidly through its 

digestive tract. It may be retained for several days, increasing internal contact and the 

likelihood that toxic compounds will be absorbed. The risk of gut impaction also 

increases for turtles that have ingested oil. 

Risk of Oil Spills in Sea Turtle Habitat

To their widespread distribution throughout the GOM, and life history stages on both 

beach and marine environments, sea turtles have a high potential to be affected by an oil 

spill resulting from the proposed lease sales. Sea turtle habitat in the GOM includes 

inshore, shelf, and oceanic waters, as well as numerous beaches in the region. Based on 

the OSRA, many, frequent, small spills; few, infrequent, moderate-sized spills; and a 

single, unlikely, large spill have been estimated. 

In nearshore waters of the WPA, spill estimates indicate that spills <42 U.S. gallons (gal) 

(42 U.S. gallons = 1 bbl) will introduce 546-1,218 gal of oil into coastal waters over the 

40-year life of the proposed lease sales. Spills >42 gal and <42,000 gal of oil are 

expected to introduce 6,426-12,852 gal of oil in coastal waters of the WPA. A single 

74
spill >42,000 gal of oil may occur and the total volume of spilled oil introduced into 

coastal waters of the WPA ranges from 6,972-140,070 gal. 

In nearshore waters of the CPA, spill estimates indicate that between 42 and 92 spills of 

<42 gal of oil will be introduced into coastal waters. An additional 12,852-32,004 gal of 

oil are estimated to be spilled into coastal waters of the CPA from spills of >42 to 

<42,000 gal. A total of 14,616-161,868 gal of spilled oil is estimated for coastal waters 

of the CPA. 

In offshore waters of the WPA, estimates from spill data indicate many frequent small 

spills (<42 gal); few, infrequent, moderately-sized spills (>42 gal and <42,000 gal); and/ 

or rare large spills as a result of the proposed actions. An estimated 2,394-4,158 gal of 

oil will be introduced in offshore waters from small spills (<42 gal). An additional 

15,582-52,290 gal of oil will be spilled in quantities of a >42 to <42,000 gal spill event. 

A single, large spill (>42,000 gal) is estimated to introduce approximately 193,200 gal of 

oil. A single, but unlikely, spill may occur that introduces as much as 630,000 gal of oil. 

The total volume of oil spilled in offshore waters as a result of the proposed actions in the 

WPA is estimated at 15,582-875,490 gal of oil spread over the 40-year life span of the 

proposed actions. In offshore waters of the CPA, small spills (<42 gal) are projected to 

introduce 7,644-12,768 gal of oil. Moderate-sized spills (>42 and <42,000 gal), though 

occurring less frequently than smaller spills, will introduce an estimated 37,128-86,982 

gal of oil. One or two large spills (>42,000 gal) are assumed to introduce approximately 

193,200-386,400 gal of oil as a result of proposed actions in the CPA. In the rare event 

that a spill exceeding 420,000 gal should occur, it is estimated that approximately 

630,000 gal of oil will be spilled over the 40-year lifetime of the proposed leases in the 

CPA.

7.3.2 Effects of Oil on Sperm Whales 

A large accidental spill may impact sperm whales in the GOM. Because the of the 

matriarchal social structure of sperm whales, an accidental oil spill affecting sperm 

whales could potentially affect the whole group in the area, including adult females, 

calves, and juveniles of either sex. Sperm whales are deep divers and generally forage 

over large areas so that the magnitude of oil exposure would depend, in part, on the 

location of the spill, the composition of the spilled material, and the movement and fate 

of the spilled hydrocarbons/wastes in the offshore environment. Spilled hydrocarbons 

could affect sperm whales through various pathways including surface contact, oil 

inhalation, and oil ingestion. Direct contact with oil can result in irritation and damage to 

skin and soft tissues of cetaceans. Hydrocarbons absorbed in the blood stream may 

accumulate in the brain and liver and result in neurological disorders. Sperm whales in 

the GOM could be exposed to residuals of oils spilled as a result of proposed actions over 

the life of the lease resulting from the proposed lease sales. 

Risk of Oil Spills in Sperm Whale Habitat 

Blowouts, oil spills, and spill-response activities have the potential to adversely affect 

sperm whales in the offshore environment. There are 1-2 blowouts projected to occur 

from a proposed lease sale in the WPA and 2-3 blowouts projected from a proposed lease 

75
sale in the CPA. It is expected that slicks from spills <42,000 gal will persist a few 

minutes (<42 gal), a few hours (<420 gal), or a few days (420-42,000 gal) on the open 

ocean. Large spills, particularly those continuing to flow fresh hydrocarbons into oceanic 

and/or outer shelf waters for extended periods (days, weeks, months), pose an increased 

likelihood of impacting cetacean populations inhabiting these waters. Oil-spill data 

derived from historical trends estimate that a total volume of 237,972-1,116,150 gal of oil 

will be introduced into federal offshore waters over 40 years as a result of the proposed 

lease sales in the CPA. Small spills (<42 gal) are projected to introduce 7,644-12,768 gal 

of oil. Moderate-sized spills (>42 and <42,000 gal), though occurring less frequently 

than smaller spills, will introduce an estimated 37,128-86,982 gal of oil. One or two 

large spills (>42,000 gal) are assumed to introduce approximately 193,200-386,400 gal of 

oil as a result of proposed actions in the CPA. In the rare event that a spill exceeding 

420,000 gal should occur, it is estimated that approximately 630,000 gal of oil will be 

spilled. Spilled oil would rapidly spread out, evaporate, and weather, quickly becoming 

dispersed into the water column. Potential effects include physical injury and irritation, 

respiratory stress from inhalation of toxic fumes, food reduction or contamination, direct 

ingestion of oil and/or tar, and temporary displacement from preferred habitats. 

7.3.3 Effects of Oil on Gulf Sturgeon 

The risk of exposure of Gulf sturgeon to such a spill would be dependent upon the 

species abundance in the area affected by a spill, as well as the size and persistence of the 

slick. Oil spill probability models were run for Gulf sturgeon critical habitat and for a 

swath from the mouth of the Mississippi River to Tampa Bay for known Gulf sturgeon 

locations. The Gulf sturgeon is an anadromous fish; adults spawn in freshwater then 

migrate to feed and grow in estuarine/marine habitats. After spawning in the upper river 

reaches, both adult and subadult Gulf sturgeon migrate to the estuaries, bays, and the 

GOM and return to the coastal rivers in early spring (i.e., March through May) when river 

water temperatures range from 16°C to 23°C (Huff 1975, Carr 1983, Wooley and Crateau 

1985, Odenkirk 1989, Clugston et al. 1995, Foster and Clugston 1997, Fox and 

Hightower 1998, Sulak and Clugston 1999, Fox et al. 2000). Surveys have located adult 

Gulf sturgeon in rivers predominantly in the summer months (May-August) with adults 

rare or absent in the rivers during fall and winter months when they migrate seaward into 

the adjacent estuarine and marine habitats (Craft et al. 2001, Berg 2004). Based on the 

life history of this species, subadult and adult would be most vulnerable to an estuarine or 

marine oil spill, and would only be vulnerable during winter months (between September 

1 through April 30) when this species is foraging in estuarine and marine habitats. 

Risk of Oil Spills in Gulf Sturgeon Habitat

The area analyzed for oil spill probability is the area in which Gulf sturgeon are known to 

occur, from the Mississippi River to Charlotte Harbor in western Florida. This 

geographic range of Gulf sturgeon is larger than the designated critical habitat. 

The inclusion of the eastern Louisiana portion differs from the oil spill analysis 

performed for critical habitat and results in different oil spill contact probabilities. Gulf 

sturgeon designated critical habitat does not include the Mississippi River delta 

(southeastern-most portion of Louisiana to the river mouth); resulting in greater risk of an 

76
oil spill affecting Gulf sturgeon than their critical habitat. Based on the OSRA conducted 

for Gulf sturgeon, the area of the Mississippi River delta has the highest risk of being 

affected by an oil spill. There is a 6 to 9 percent chance that a spill >42,000 gal would 

occur as a result of a proposed action in the CPA and reach coastal waters of the delta 

region within 10 days. 

7.3.4 Estimation of Exposure and Take from Oil Spills

Oil spills are rare events, but they have the potential to be devastating to the listed species 

in the area affected when they occur. The time, location, and size of an oil spill, and oil 

spill response activities may determine the potential impacts to listed species. 

Immediately upon being spilled, oil begins to weather, including the evaporation of 

volatile hydrocarbons, dissolution of soluble components, dispersion into the water 

column, emulsification and spreading at the water’s surface. 

The relative risk of exposure to smaller and larger sized slicks is very much dependent on 

the size of the slick, how long it lasts, and where and when it occurs. Many of the 

variables are highly unpredictable; however, the majority of spills (75.1 percent) and the 

majority of spills by volume (83.8 percent) occur within 3 nmi of shore. Such spills place 

species inhabiting nearshore environments, or occurring in greater densities, are at greater 

risk than offshore species. 

Table 6. Mean number of spills expected over the 40-year lifetime of the proposed lease 

sales (data on spill size, spill area, and number of spills provided by MMS).

Median 

Spill Size 

(gal) 

Spill Area at 

24 hours 

(km2

)

a

Maximum 

Number of Spills 

in WPA and CPA

Days Individual 

Slick Area 

Persistsb 

Total Spill 

Area (km2

) 

Over 40 Yrs 

3 0.0000124 5,757 2 0.1427736 

126 0.0005261 129 2 0.1357338 

840 0.0040470 28 3 0.2266320 

3,780 0.0809400 11 4 3.5613600 

26,880 0.1133000 2 4 0.9064000 

193,200 0.8094000 3 5 12.141000 

Total 1.0082255 5,933 27 17.1138994 a

The spill area is based on the projected maximum surface area of the slick. The slick will become thinner 

and smaller over time, and the actual number of days a slick will persist will vary depending on weathering 

and other factors.

b

Estimate based volume of spilled oil and maximum spill area. Actual persistence of slicks may occur for 

longer periods, depending on volume, and is accounted for by applying the maximum slick area over a 

period of days. 

Many small spills are expected to be common from the proposed action (Table 6). MMS 

estimates slicks from spills <42,000 gal will persist for a few minutes and would have 

little chance of directly contacting a listed species unless individuals were in the 

immediate area at the time of the spill. The amount of oil spilled from many small 

sources is potentially greater than that of a few larger-sized spills. However, it is not 

simply infrequent or episodic spills that threaten listed species, but also the continuous 

77
low-level exposure to oil in the form of tarballs, small slicks, or elevated background 

concentrations also challenge animals facing other natural and anthropogenic stresses. 

Chronic exposure may not be lethal by itself, but it may impair an animal’s overall fitness 

so that it is less able to withstand other stressors. 

Larger spills greater than 420 gal would persist for days to over a week depending on the 

size and weathering of the slick. Although larger spills are expected to occur much less 

frequently (Table 6), these larger spills have the greatest potential to adversely affect 

listed species, and may result in more severe affects. MMS expects that approximately 

one major oil spill could occur over the 40 years of the proposed action. 

Sea Turtles 

Spills originating in or migrating through coastal waters of Texas or Louisiana may 

impact any of the five sea turtle species inhabiting the GOM. Spills occurring in offshore 

waters would be expected to have less a chance of affecting sea turtles due to their lower 

densities in deep water; however, leatherback sea turtles may be expected to have a 

greater risk of adverse effects in offshore environments than nearshore environments. 

Takes from oil spills may be lethal or non-lethal ranging from a wide array of effects 

including changes in biologically important behaviors to mortality. It has been estimated 

that approximately 1 percent of annual sea turtle strandings are associated with oil. 

Higher percentages are attributed to oil in South Florida (3 percent) and Texas (3 to 6 

percent) (Lutcavage et al. 1997). Oil removed from stranded sea turtles in Florida and 

Texas has been identified primarily as tanker discharges, not the result of accidental 

spills. 

Based on projected spill estimates, there is a small risk that an individual sea turtle will 

encounter a single small oil slick that does not persist long in the environment. Longterm exposure to contaminants from many small oil spills may play a cumulative role, but 

these potential effects are mostly unknown at this time. Small spills are expected to be 

much more numerous than large spills, but the fewer, larger slicks have a greater 

potential for adverse affects due to the increased chance that sea turtles will be exposed to 

large slicks over short periods due to its larger size and greater persistence in the 

environment than smaller slicks. 

Because oil spills are unpredictable, we look to a catastrophic oil spill, the Ixtoc I oil spill 

in 1979, to estimate impacts. During this spill, prevailing northerly currents in the 

western Gulf of Mexico carried spilled oil toward the United States. A 60-mile by 70-

mile patch of sheen containing a 300 ft by 500 ft patch of heavy crude moved toward the 

Texas coast. The heavy crude impacts a relatively small area and contributes to the 

sheen, tarballs, and other residuals through weathering. On August 6, 1979, tarballs from 

the spill impacted a 17 mile stretch of Texas beach. With new technologically advances 

and oil spill prevention and response plans, a major oil spill in the GOM would not likely 

be as large as Ixtoc I (Minerals Management Service 2006). In the following analysis we 

use one-half estimates of the approximate maximum spill area from Ixtoc I to estimate 

potential impacts from a major oil spill occurring as a result of the proposed action. It 

should be noted that this estimate likely applies to all oil and gas operations in the GOM 

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over a 40-year period, but the risk of any one action (i.e., a lease sale) must be assumed to 

be equal. Table 7 uses the following oil spill scenario and assumptions in the 

calculations: 

• a 30-mile by 40-mile wide area would affect approximately 3,108 km2

 of 

ocean surface with oil sheen, 

• a 150 ft by 250 ft area of heavy crude would affect 0.0035 km2 of water, 

• a 9-mile long by 3-mile wide stretch of coastal habitat affected by tarballs 

would impact approximately 70 km2 of water, and 

• individuals are assumed to be resident in the area during the duration of the 

spill so animals aren’t repeatedly counted, but may be repeatedly exposed 

during the duration of the spill. 

Table 7. One-day exposure estimates of sea turtles to a major oil slick occurring over the 

40-year lifetime of the proposed lease sales. 

Spill Area (km2)

b

leatherback 

(0.0026)

green 

(0.0142)

Kemp’s ridley 

(0.0047)

loggerhead 

(0.0443)

hawksbill 

(0.0000)

3,108 (sheen) 8.08 44.13 14.61 137.68 <0.05 

0.0035 (heavy crude) <0.05 <0.05 <0.05 <0.05 <0.05 

70 (tarballs) 0.18 1 0.33 3.10 <0.05 a

Numbers in ( ) following each species name are upper confidence limits of greatest reported density in 

water depths <200 m of the western GOM reported in Epperly et al. 2002.

In the event an oil spill were to occur, the actual numbers of individuals affected would 

be dependent upon the size and location of the slick, the type of oil released, and the 

abundance of sea turtles in the area. Since tarballs may persist in the environment over a 

much longer period than the slick lasts, an additional number of turtles could potentially 

be adversely affected by tarball ingestion. Although direct exposure to heavy crude 

would likely be lethal due to heavy oiling of the entire body surface, the risk of exposure 

to heavy crude is very low due to the small surface area. Risk of exposure to the sheen is 

much greater due to the greater surface area of oil spreading across the surface the water. 

Hatchlings and juveniles are expected to be more vulnerable to lethal effects of oil spills 

due to their increased time at the surface, smaller size, and lesser mobility than that of 

adults. Although short-term physiological effects may occur depending on the level and 

duration of exposure, most fatalities due to oiling are from covering of the mouth and 

nares (nostrils) that can prevent an animal from breathing if the individuals we not 

treated. Because the amount of oiling of hatchlings may vary depending on factors such 

as the thickness of the sheen at the surface, the duration of the spill, and whether or not 

the animals were recovered and rehabilitate during oil spill response, we expect 

approximately one-half of exposed hatchlings and juveniles to be killed due to a major oil 

spill. Lethality of adults would be expected to be much lower than that of hatchlings due 

to their greater size, strength, and mobility. Although short-term physiological effects 

have been shown to occur in adult sea turtles, we estimate that approximately 1 in 10 

adults will suffer chronic affects resulting in death from a major oil spill. 

79
The exposure estimates to a surface sheen of a given area are considered reliable since 

animals must surface to breathe. However, when considering tarball ingestion, tarballs 

will not be evenly distributed and a sea turtle must actually ingest the tarball to be 

affected such that exposure does not necessarily equate to a take. Addtionally, although 

tarballs may persist in the environment for unknown durations, making predictions of 

take by ingestion is problematic due to uncertainties in actually encounter rates during 

foraging, and whether the tarballs resulted from an accidental spill, or from other sources 

such as natural seeps and bilge water discharges. Due to the uncertainty regarding 

actually encounter rates between sea turtles and tarballs in the environment, we must rely 

on an approximate estimate that tarballs from a large oil spill would persist for 5 years 

and be encountered by any individual once per year. 

Although the occurrence, size, time of year, and location of an oil spill is highly 

unpredictable, we expect sea turtles to be adversely affected by a major oil spill. Due to 

the lack of data of life history stages and the unpredictable location of a major oil spill 

occurring, we have made the assumption that hatchlings/juveniles and adult sea turtle 

have an equal chance of being affected by an oil spill; however, when the number of 

individuals taken is an odd number, we expect adults to have the slightly higher risk of 

tarball ingestion due to their generally greater amount of prey ingested than smaller 

individuals. We estimate the following take of sea turtles from a major oil spill occurring 

during the 40-year lifetime of the proposed action. 

 

Species Sheen Tarball Ingestion 

Lethal Non-Lethal Lethal Non-Lethal 

Hatchlings/Juveniles (0.50 lethal)

 leatherback 2 2 0 0 

 green 11 11 0 2 

 Kemps’ ridley 8 7 0 1 

 loggerhead 35 34 0 7 

Adults (0.10 lethal)

 leatherback 0 4 0 1 

 green 2 20 0 3 

 Kemps’ ridley 1 7 0 1 

 loggerhead 7 62 0 8 

 hawksbill 0 0 0 1 

Numbers greater than 0.50 have been rounded up to the nearest whole number. The risk of hawksbill sea 

turtles being is low, but spills occurring in south Texas may affect this species through tarball ingestion. 

Sperm Whales 

Although some sperm whales may be able to avoid oil spills or slicks following detection 

of hydrocarbons at the surface, it is highly unlikely that they are capable of avoiding spill 

residuals in their environment. Consequently, the probability that a marine mammal is 

exposed to hydrocarbons resulting from a spill extends well after the oil spill has 

dispersed, and may be exposed to residuals of oils spilled as a result of the proposed 

actions during their lifetimes, but the effects of these residuals is largely unknown. 

Although an interaction with a spill could occur, primarily sublethal effects are expected 

80
due to avoidance and natural dispersion/weathering of the spill in the offshore 

environment or long-term exposure to hydrocarbons in the marine environment. 

Based on the majority of oil production closer to shore and oil spills 75% of oil spills 

occurring within 3 nmi of the shoreline, there is a lower likelihood of sperm whales being 

exposed to oil slicks over the 40-year lifetime of the action. However, because spills are 

unpredictable events and sperm whales can be found throughout the GOM, it is likely at 

least one sperm whale will come into contact with a slick if a spill were to occur in an 

area being used by sperm whales at that time. Considering the density of sperm whales 

in the GOM (0.0035 individuals km-2) and the spill area of a major oil spill sheen in 

Table 7 (3,108 km2), we estimate the following take of sperm whales: 

• 11 non-lethal takes of sperm whales over the 40-year lifetime of the action.

Gulf sturgeon 

Due to benthic habits of Gulf sturgeon, their presence in marine waters only during the 

winter, and the low risk of an oil spill contacting them in only the western-most area of 

their range, there is a relatively low risk of exposure to oil. Because they are not known 

to do not breach the surface in estuarine and marine waters, an exposure analysis to the 

surface slick has not been conducted. However, based on the oil spill risk probability, 

some oil may be expected to come into contact with Gulf sturgeon habitat over the 40-

year life of the proposed lease sales, and in NMFS opinion may affect some individuals 

due to weathering of the slick in nearshore environments along the coastline. In general, 

a surface slick would not be expected to adversely affect Gulf sturgeon due their benthic 

habits; however, NMFS expects that a slick reaching shallow coastal waters less than 15 

feet may mix throughout the water column and potentially affect sturgeon. two Gulf 

sturgeon are likely to be lethally taken and another two non-lethally taken by an oil spill 

over the 40-year life of the proposed lease sales that affect shallow water environments 

where oil may mix throughout the water column. Although oil spills are unpredictable 

events, the OSRA indicates a 6 to 9 percent chance that a spill >42,000 gal would reach 

coastal waters of the westernmost portion of the Gulf sturgeon’s range within 10 days. 

Due to the risk of oil spills on the fringe of Gulf sturgeon’s range, we estimate the 

following: 

• Two lethal takes of Gulf sturgeon over the 40-year lifetime of the proposed 

action. 

8 CUMULATIVE EFECTS 

Cumulative effects include the effects of future state, tribal, local, or private actions, not 

involving federal activities, reasonably certain to occur within the action area considered 

in this biological opinion (i.e., the WPA and CPA of the GOM). Future federal actions 

that are unrelated to the proposed action are not considered in this section because they 

require separate consultation pursuant to section 7 of the ESA. 

81
Cumulative effects may affect sea turtle species, Gulf sturgeon, sperm whales, and their 

habitats in the action area. The actions and their effects described as occurring within the 

action area in the Environmental Baseline are expected to continue in the future. We are 

not aware of any proposed or anticipated changes to these actions that would 

substantially change the impacts that each threat has on listed species considered by this 

biological opinion. Therefore, we expect the effects of these actions on listed species will 

continue at similar levels into the foreseeable future. 

9 JEOPARDY ANALYSIS 

This section considers the likelihood that the proposed five-year lease sale plan will 

jeopardize the continued existence of listed species in the wild that have been considered 

in the effects of the action. To Jeopardize the continued existence of is defined as “to 

engage in an action that reasonably would be expected, directly or indirectly, to reduce 

appreciably the likelihood of both the survival and recovery of a listed species in the wild 

by reducing the reproduction, numbers, or distribution of that species” (50 CFR 402.02). 

The effects of the action considered the effects of vessel strikes on sea turtles, the effects 

of seismic exploration on sperm whales, and the effects of accidental oil spills on listed 

species of sea turtles, sperm whales, and Gulf sturgeon resulting from the proposed fiveyear lease sale plan. The following jeopardy analysis first considers the effects of the 

action to determine if we would reasonably expect the action to result in reductions in 

reproduction, numbers, or distribution of these listed species. The analysis next considers 

the effects of the action in light of the status of the species, the environmental baseline, 

and cumulative effects, to determine whether the likelihood of survival of each species in 

the wild, and the likelihood of recovery of each species in the wild, would be appreciably 

reduced. 

9.1 Effects of the Action on the Likelihood of Survival in the Wild 

This section analyzes the effects of the action on the likelihood of survival of each 

species in the wild. In this context, the survival of the species refers to the continued 

existence of the species in the wild, and whether or not any anticipated take of that 

species will result in any reduction in reproduction, numbers, or distribution of that 

species that may appreciably increase a species’ risk of extinction in the wild. 

Likelihood of Loggerhead Sea Turtle Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of loggerhead sea turtles will 

not appreciably increase the risk of extinction of this species in the wild. 

The non-lethal take of 238 individuals by vessel strike and 111 individuals by oil spill 

over the 40-year lifetime of the action could potentially result in short-term affects on 

individuals. Sea turtles are generally known to not avoid oil slicks, and are often found 

near oil and gas operations. Changes in distribution, even short-term, are not expected 

from non-lethal takes from oil spills. However, interactions with vessels may elicit 

startle or avoidance responses and the effects of the proposed lease sales may result in 

82
temporary changes in behavior of sea turtles (minutes to hours) over small areas, but are 

not expected to reduce the distribution of any loggerhead sea turtles in the action area. 

Lethal takes by vessel strike or oil spill may occur anywhere throughout the GOM. The 

removal of 119 individuals by vessel strike and 42 individuals by oil spill is anticipated 

over 40 years of the proposed action. Because all the potential takes are expected to 

occur anywhere in the action area and sea turtles generally have large ranges in which 

they disperse, no reduction in the distribution of loggerheads is expected from the take of 

these individuals. 

Although changes in distribution will not occur, there is some potential for the 

reproductive ability of non-lethally taken turtles to be affected due to the presence of 

nesting beaches within reach of potential oil spills. For example, if a nesting beach was 

affected by an oil slick, nesting ability or hatchling survival could potentially be affected 

for that year, but the individual is expected to survive and return to unimpeded 

reproduction in subsequent years. Some long-term, non-lethal effects to hydrocarbon 

residues from spills and ingestion of tarballs may affect sea turtle physiology. In spite of 

these effects, it appears non-lethal, chronic exposure or repeated ingestion of oil is 

necessary for any long-term affects to be detectable, yet no effects on the reproduction or 

number of sea turtles from long-term exposure to residuals or tarball ingestions have been 

observed in the wild. Non-lethal takes by vessel strike aren’t expected to have any 

measurable impact on the reproduction of numbers of loggerheads. The reaction to and 

injury incurred from vessel impacts would be dependent on the operational speed of the 

vessel, depth of the turtle, bow type, and other factors. The non-lethal takes may range 

from startle reactions to minor injury, and are expected to recover within an appropriate 

amount of time, depending on the magnitude of impact. Although the range of impacts 

of non-lethal takes are variable, all are expected to be fully recoverable such that no 

reductions in reproduction or numbers of loggerheads are anticipated. 

The removal of 119 individuals by vessel strike and 42 individuals by oil spill 

(approximately 4 individuals annually), would result in an instantaneous, but temporary 

reduction in total population numbers. Sea turtles lethally affected by vessels and spilled 

oil may be juveniles or adults, with about 2 adults and 3 juveniles every 1.5 years, of 

which half those adults would be mature females (about 33 adult females over the 40-

year lifetime of the lease sales). Thus, the action will result in a reduction of loggerhead 

numbers. Sea turtle mortality resulting from vessel interactions or spilled oil could result 

in the loss of reproductive value of an adult turtle. An adult loggerhead sea turtle can lay 

3 or 4 clutches of eggs every 2 to 4 years, with 100 to 130 eggs per clutch. The annual 

loss of 1.5 adult females, on average, could preclude the production of thousands of eggs 

and hatchlings, of which a small percentage are expected to survive to sexual maturity. 

Thus, the death of a female eliminates an individual’s contribution to future generations, 

and the action will result in a reduction in loggerhead reproduction. Below, we consider 

the population trends for loggerhead sea turtles and the effect that the anticipated 

reduction in numbers and reproduction has on the survival of the species. 

Five northwestern Atlantic loggerhead subpopulations have been identified (NMFS 

SEFSC 2001). The most recent reviews show that only two loggerhead nesting beaches 

83
have greater than 10,000 females nesting per year: South Florida (U.S.) and Masirah 

Island (Oman). Total estimated nesting in the U.S. is approximately 68,000 to 90,000 

nests per year. A yet-to-be-published analysis of nesting data from 1989-2005 by FWRI 

indicates there is a trend for declining nesting at beaches utilized by the south Florida 

nesting subpopulation (2006 FWRI letter (McRae) to NMFS, based on statewide nesting 

beach survey data analyzed by FWRI). Similarly, long-term nesting data show 

loggerhead nesting declines in North Carolina, South Carolina, and Georgia. Loggerhead 

populations in Honduras, Mexico, Colombia, Israel, Turkey, Bahamas, Cuba, Greece, 

Japan, and Panama have been declining. 

In other regions, the Eastern Atlantic, the Cape Verde Islands support an intermediatelysized loggerhead nesting assemblage. In 2000, researchers tagged over 1,000 nesting 

females on just 5 km (3.1 mi) of beach on Boavista Island (Ehrhart et al. 2003). In the 

Western Atlantic (excluding the U.S.), published and unpublished reports provide an 

estimate of about 4,000 nests per year in Brazil (Ehrhart et al. 2003). In the 

Mediterranean, the recorded number of nests per year in Cyprus, Greece, Israel, Tunisia, 

and Turkey, loggerhead nesting in the Mediterranean ranges from about 3,300 to 7,000 

nests per season (Margaritoulis et al. 2003). A small, but unknown nesting population 

size of loggerheads nest throughout the Indian Ocean. 

All life stages are important to the survival of the species; however, it is important to note that 

individuals of one life stage are not equivalent to those of other life stages. Loggerhead sea 

turtles have very long developmental times before reaching maturity (up to 38 years). 

Individuals in earlier life stages are subject to many potential sources of mortality, both natural 

and human-induced, prior to reaching sexual maturity. Only a fraction of pelagic juveniles are 

ever expected to contribute to the population through reproduction, and thus are not as valuable 

to the population as a breeding age adult. The loss of a certain number of pelagic juveniles, 

therefore, is less of a threat to the species’ survival compared to an equal loss of sexually-mature 

adults. 

It is unclear at this time if the current data from major nesting beaches indicate a 

declining trend in total population size, or is the result of some other factor such as 

regional failure to nest by the reproductively mature females, variable recruitment 

resulting in a biased age structure in the population, environmental factors (e.g., resource 

depletion, nesting beach conditions, oceanographic conditions, etc.), or some natural 

variation in nesting patterns over time. Whether the decreased trend some 

subpopulations are currently experiencing are associated with affects these populations 

experienced decades ago, or is associated with some other variable currently affecting 

nesting numbers is unknown. How these nesting trends will change in the future is 

uncertain at this time and being analyzed by the TEWG. Although some natural 

variability is expected in nesting trends, recruitment of adults into the breeding 

population could potentially occur if this trend continues over the long-term. 

The low number of expected loggerhead mortalities (approximately four individuals 

annually of different sex and age classes) is not detectable. Considering the population 

size in the Western North Atlantic, we believe the loggerhead population is sufficiently 

84
large enough to persist and recruit new individuals to replace those expected to be taken. 

The TEWG (1998) estimated the total loggerhead population of benthic individuals in 

U.S. waters – a subset of the whole Western Atlantic population – at over 200,000. 

Based on this estimate, the mortality of 161 loggerheads (approximately 81 juveniles, 40 

male adults, and 40 female adults) over the 40-year lifetime of the proposed action would 

be less than 0.0009% of the current total eastern U.S. population. 

Although the anticipated mortalities would result in an instantaneous reduction in 

absolute population numbers, it is likely that the U.S. populations of sea turtles would not 

be appreciably affected considering the following. For a population to remain stable, sea 

turtles must replace themselves through successful reproduction at least once over the 

course of their reproductive lives, and at least one offspring must survive to reproduce 

itself. If the hatchling survival rate to maturity is greater than the mortality rate of the 

population, the loss of breeding individuals would be replaced through recruitment of 

new breeding individuals from successful reproduction of non-taken sea turtles. 

Although the causes of the declining trend of major nesting subpopulations are unknown 

at this time, the present population size is sufficiently large for the persistence of this 

species. This is evident in this analysis by the fact that loggerheads are expected to be 

taken in greater numbers than other species of sea turtles due to their higher abundance 

and densities in the GOM, despite the negative trend in nesting observed over the last 

several years. Although the declining numbers of major nesting subpopulations requires 

further study and analysis to determine the causes and long-term effects on population 

dynamics, the species’ likelihood of survival in the wild will not be appreciably reduced 

as a result of this action.. 

Summary of Loggerhead Sea Turtle Survival 

Based on the above analysis, we believe that the lethal and non-lethal takes of loggerhead 

sea turtles associated with the proposed action are not reasonably expected to cause, 

directly or indirectly, an appreciable reduction in the likelihood of survival of loggerhead 

sea turtles in the wild. 

Likelihood of Leatherback Sea Turtle Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of leatherback sea turtles will 

not appreciably increase the risk of extinction of this species in the wild. 

The non-lethal take of 21 individuals by vessel strike and 7 individuals by oil spill over 

the 40-year lifetime of the action could potentially result in short-term affects on 

individuals. Sea turtles are generally known to not avoid oil slicks, and are often found 

near oil and gas operations. Changes in distribution, even short-term, are not expected 

from non-lethal takes from oil spills. However, interactions with vessels may elicit 

startle or avoidance responses and the effects of the proposed lease sales may result in 

temporary changes in behavior of sea turtles (minutes to hours) over small areas, but are 

not expected to appreciably reduce the distribution of leatherback sea turtles in the action 

area. Lethal takes by vessel strike or oil spill may occur anywhere throughout the GOM. 

The removal of 10 individuals by vessel strike and 2 individuals by oil spill is anticipated 

85
over 40 years of the proposed action. Because all the potential takes are expected to 

occur anywhere in the action area and sea turtles generally have large ranges in which 

they disperse, no reduction in the distribution of leatherbacks is expected from the take of 

these individuals. 

When considering the non-lethal effects of an oil spill, leatherbacks have the greatest 

potential to be affected by spills in pelagic environments. Nesting by leatherbacks in the 

GOM is sporadic and no major nesting beaches occur in this region. The habitat of 

leatherbacks in the GOM is typically found in deeper, offshore waters. Due to this 

habitat, they are typically less vulnerable to spills, of which 75 percent occur within 3 

nmi of shore. Leatherbacks are deep divers foraging on prey in the water column and 

may ingest tarballs. Although some physiological effects may occur from exposure, they 

are expected to be inconsequential on reproduction. Non-lethal takes by vessel strike 

aren’t expected to have any measurable impact on the reproduction of leatherbacks. The 

reaction to and injury incurred from vessel impacts would be dependent on the 

operational speed of the vessel, depth of the turtle, bow type, and other factors. The nonlethal takes may range from startle reactions to minor injury, and individuals are expected 

to recover within an appropriate amount of time, depending on the magnitude of impact. 

Although the range of impacts of non-lethal takes are variable, all are expected to be fully 

recoverable such that no reduction in reproduction or numbers of leatherbacks are 

anticipated. 

A total of 10 leatherbacks are expected to be lethally taken by vessel strike and 2 by oil 

spill over the 40-year lifetime of the proposed lease sales (approximately 1 individual 

every 3.3 years, on average). Leatherbacks lethally taken by vessels and spilled oil may 

be juveniles or adults, with about 5 adults and 7 juveniles over a period of 40 years, of 

which half those adults would be mature females (about 2-3 adult females over the 40-

year lifetime of the lease sales). Thus, the action will result in a reduction of leatherback 

numbers. The expected mortalities will eliminate an individual’s contribution to future 

generations; thus, resulting in a reduction in reproduction. Below, we consider the 

population trends for leatherback sea turtles and the effect that the anticipated reduction 

in numbers and reproduction has on the survival of the species. 

The Pacific Ocean leatherback population is generally smaller in size than that in the 

Atlantic Ocean. Because adult female leatherbacks frequently nest on different beaches, 

nesting population estimates and trends are especially difficult to monitor. In the Pacific, 

the World Conservation Union (IUCN) notes that most leatherback nesting populations 

have declined more than 80%. In other areas of the leatherback's range, observed 

declines in nesting populations are not as severe, and some population trends are 

increasing or stable. Nesting trends on U.S. beaches have been increasing in recent years. 

Leatherback nesting trends for individual beaches are considerably variable, dependent 

upon natural fluctuations in beach conditions throughout the Atlantic basin; therefore, 

basin-wide estimates may be a better indicator of population trends than nesting data 

trends for individual beaches. Spotila et al. (2001) estimated that the mean population 

number of leatherbacks in the Atlantic basin totaled approximately 27,600 nesting 

86
females (20,082-35,133). We believe that the current population probably still lies within 

this range, taking into account the natural variation at individual nesting beaches. 

Similar to the discussion of the relative importance of various life stages in the 

loggerhead section above, the removal of different age classes or sexes has different 

consequences on the population of leatherbacks as well. According to Spotila et al. 

(1996), survivorship in the juvenile/sub-adult stage of leatherback sea turtles is vitally 

important to the future of the species; population models are most sensitive to variation in 

juvenile/sub-adult survival. The number of individuals in the various stages would also 

not be as disparate in leatherbacks as in loggerheads. Assuming an equal chance or 

mortality for both juveniles and adults, only 2-3 adult female leatherbacks would be 

expected to be removed from the population over 40 years. Although the death of a 

female eliminates an individual’s contribution to future generations and may result in a 

reduction in reproduction, the low number of lethal takes for leatherbacks from the 

proposed action indicates a greater chance of successful breeding or replacement of 

individuals through recruitment. 

For example, if a leatherback successfully nested in a single nesting season and only one 

of those hatchlings survived to maturity to breed, there would be no net gain or loss to 

population numbers. Increasing numbers of hatchlings surviving to maturity would result 

in a net increase in population numbers, as long as the overall recruitment rate exceeds 

the death in the population. If a mature female leatherback were taken prior to successful 

nesting and recruitment of an individual to the breeding population, a net decrease in 

population size of that individual would be incurred. However, a net loss is not expected. 

Although the mortality of a few individuals would have an instantaneous decease in 

absolute population numbers at the time of taking, based on the population size and 

increasing nesting trend in recent years, the mortality of 12 individuals over 40 years is 

expected to have a negligible impact on population numbers. Even assuming all 

mortalities would consist of nesting females, based on the lower female nesting 

population estimate of 20,084 individuals in the Atlantic, the removal of 12 individuals 

would be <0.0007 of the total population. The replacement of these 12 individuals 

through recruitment of new individuals into the breeding population; by at least 12 sea 

turtles producing at least 2 offspring that survive to adulthood to reproduce, is expected 

in a population of this size. The expected mortality of leatherbacks is not expected to 

appreciably reduce the species’ likelihood of survival in the wild. 

Summary of Leatherback Sea Turtle Survival 

Based on the above analysis, we believe that the lethal and non-lethal takes of 

leatherback sea turtles associated with the proposed action are not reasonably expected to 

cause, directly or indirectly, an appreciable reduction in the likelihood of survival of 

leatherback sea turtles in the wild. 

Likelihood of Kemp’s Ridley Sea Turtle Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of Kemp’s ridley sea turtles 

will not appreciably increase the risk of extinction of this species in the wild. 

87
The non-lethal take of 26 individuals by vessel strike and 16 individuals by oil spill over 

the 40-year lifetime of the action could potentially result in short-term affects on 

individuals. Sea turtles are generally known to not avoid oil slicks, and are often found 

near oil and gas operations. Changes in distribution, even short-term, are not expected 

from non-lethal takes from oil spills. However, interactions with vessels may elicit 

startle or avoidance responses and the effects of the proposed lease sales may result in 

temporary changes in behavior of sea turtles (minutes to hours) over small areas, but are 

not expected to reduce the distribution of any Kemp’s ridley sea turtles in the action area. 

Lethal takes by vessel strike or oil spill may occur anywhere throughout the GOM. The 

removal of 13 individuals by vessel strike and 9 individuals by oil spill is anticipated over 

40 years of the proposed action. Because all the potential takes are expected to occur 

anywhere in the action area and sea turtles generally have large ranges in which they 

disperse, no appreciable changes in the distribution of Kemp’s ridleys is expected from 

the take of these individuals. 

Although changes in distribution will not occur, there is some potential for the 

reproductive ability of non-lethally taken turtles to be affected due to the presence of 

nesting beaches within reach of potential oil spills. For example, if a nesting beach was 

affected by an oil slick, nesting ability or hatchling survival could potentially be affected 

for that year, but the individual is expected to survive and return to unimpeded 

reproduction in subsequent years. Although oil spills are unpredictable, historical spill 

data show that large spills are uncommon in the GOM, and spill response plans to protect 

coastal resources reduce the likelihood that spills will affecting nesting beaches. Some 

long-term, non-lethal effects to hydrocarbon residues from spills and ingestion of tarballs 

may affect sea turtle physiology. In spite of these effects, it appears non-lethal, chronic 

exposure or repeated ingestion of oil is necessary for any long-term affects to be 

detectable, yet no effects on the reproduction or number of sea turtles from long-term 

exposure to residuals or tarball ingestion have been observed in the wild. Non-lethal 

takes by vessel strike aren’t expected to have any measurable impact on the reproduction 

or numbers of Kemp’s ridleys. The reaction to and injury incurred from vessel impacts 

would be dependent on the operational speed of the vessel, depth of the turtle, bow type, 

and other factors. The non-lethal takes may range from startle reactions to minor injury, 

and are expected to recover within an appropriate amount of time, depending on the 

magnitude of impact. Although the range of impacts of non-lethal takes are variable, all 

are expected to be fully recoverable such that no reductions in reproduction or numbers 

of Kemp’s ridley sea turtles are anticipated. 

A total of 13 Kemp’s ridleys are expected to be lethally taken by vessel strike and 9 

individuals by oil spills over the 40-year lifetime of the proposed lease sales 

(approximately 1 individual every 2.2 years, on average). Thus, the action will result in a 

reduction of Kemp’s ridley numbers. The expected mortalities will eliminate an 

individual’s contribution to future generations; thus, resulting in a reduction in 

reproduction. Below, we consider the population trends for Kemp’s ridley sea turtles and 

the effect that the anticipated reduction in numbers and reproduction has on the survival 

of the species. 

88
The total population of Kemp’s ridleys is not known, but nesting has been increasing 

significantly in the past several years (9 to 13 percent per year) with a trajectory that 

should meet or exceed recovery goals. Kemps’ ridleys mature and nest at an age of 7-15 

years, which is earlier than other chelonids. A younger age at maturity may be a factor in 

the response of this species to recovery actions. A period of steady increase in benthic 

immature ridleys has been occurring since 1990 and appears to be due to increased 

hatchling production and an apparent increase in survival rates of immature sea turtles 

beginning in 1990. The increased survivorship of immature sea turtles is attributable, in 

part, to the introduction of turtle excluder devices (TEDs) in the United States and 

Mexican shrimping fleets and Mexican beach protection efforts. The TEWG (2000) 

projected that Kemp’s ridleys could reach the Recovery Plan’s intermediate recovery 

goal of 10,000 nesters by the year 2015. 

Similar to the discussion of the relative importance of various life stages in the 

loggerhead section above, the removal of different age classes or sexes has different 

consequences on the population of Kemp’s ridleys as well. Lethal takes by vessel strike 

or oil spill may occur at random anywhere throughout the GOM, are will not affect the 

distribution of this species in any way. Kemp’s ridleys taken by vessels and spilled oil 

may be juveniles or adults, with an estimated 8 adults every 5 years, of which half those 

adults would be mature females (about 1 adult female every 10 years, or approximately 4 

females over the 40-year lifetime of the lease sales). 

All life stages are important to the survival and recovery of the species; however, it is 

important to note that individuals of one life stage are not equivalent to those of other life 

stages. Individuals in earlier life stages are subject to many potential sources of 

mortality, both natural and human-induced, prior to reaching sexual maturity. Only a 

fraction of pelagic juveniles are ever expected to contribute to the population through 

reproduction, and thus are not as valuable to the population as a breeding age adult. 

Sea turtle mortality resulting from vessel interactions or spilled oil could result in the loss 

of reproductive value of an adult turtle. The loss of 1 adult females every 10 years, on 

average, could preclude the production of thousands of eggs and hatchlings, of which a 

small percentage are expected to survive to sexual maturity. However, the population of 

Kemp’s ridleys is increasing and the removal of these individuals is not expected to have 

any detectable impact on population numbers in the wild. The proportional change in 

overall survival of Kemp’s ridleys from the loss of one individual every two years would 

be insignificant. The number of younger sea turtles recruiting into the adult or subadult 

population and their future potential reproductive value would quickly exceed the 

incidental take of these individuals and its future reproductive value. 

Based on the above analysis, the anticipated lethal take of 22 individuals on the 

population would not be expected to be detectable. 

Summary of Kemp’s Ridley Sea Turtle Survival 

Based on the above analysis, we believe that the lethal and non-lethal takes of Kemp’s 

ridley sea turtles associated with the proposed action are not reasonably expected to 

89
cause, directly or indirectly, an appreciable reduction in the likelihood of survival of 

Kemp’s ridley sea turtles in the wild. 

Likelihood of Green Sea Turtle Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of green sea turtles will not 

appreciably increase the risk of extinction of this species in the wild. 

The non-lethal take of 76 individuals by vessel strike and 36 individuals by oil spills over 

the 40-year lifetime of the action could potentially result in short-term effects in the 

fitness of individuals. Sea turtles are generally known to not avoid oil slicks, and are 

often found near oil and gas operations. Changes in turtle distribution, even short-term, 

are not expected from oil spills. However, interactions with vessels may elicit startle or 

avoidance responses and the effects of the proposed lease sales may result in temporary 

changes in behavior of sea turtles (minutes to days) over small areas, but are not expected 

to reduce the distribution of any green sea turtles in the action area. Lethal takes by 

vessel strike or oil spill may occur anywhere throughout the GOM. The removal of 38 

individuals by vessel strike and 13 individuals by oil spill is anticipated over 40 years of 

the proposed action. Because all the potential takes are expected to occur anywhere in 

the action area and sea turtles generally have large ranges in which they disperse, no 

reduction in the distribution of green sea turtles is expected from the take of these 

individuals. 

Although changes in distribution will not occur, there is some potential for the 

reproductive ability of non-lethally taken turtles to be affected due to the presence of 

nesting beaches within reach of potential oil spills. For example, if a nesting beach was 

affected by an oil slick, nesting ability or hatchling survival could potentially be affected 

for that year, but the individual is expected to survive and return to unimpeded 

reproduction in subsequent years. Although oil spills are unpredictable, there are no 

green sea turtle nesting beaches likely to affected by oil spills resulting from the proposed 

action. Some long-term, non-lethal effects to hydrocarbon residues from spills and 

ingestion of tarballs may affect sea turtle physiology. In spite of these effects, it appears 

non-lethal, chronic exposure or repeated ingestion of oil is necessary for any long-term 

effects to be detectable, yet no effects on the reproduction or number of sea turtles from 

long-term exposure to oil residuals or tarball ingestions have been observed in the wild. 

Non-lethal takes by vessel strike are not expected to have any measurable impact on the 

reproduction or numbers of green sea turtles. The reaction to and injury incurred from 

vessel impacts would be dependent on the operational speed of the vessel, depth of the 

turtle, bow type, and other factors. The non-lethal takes may range from startle reactions 

to minor injury, and turtles are expected to recover within an appropriate amount of time, 

depending on the magnitude of impact. Although the range of impacts of non-lethal 

takes is variable, all impacts are expected to be fully recoverable from such that no 

effects to reproduction or numbers of green sea turtles are anticipated. 

The lethal take of 38 green sea turtles by vessel strikes and 13 individuals by oil spills 

over a period of 40 years of the proposed action (1.3 individuals per year, on average) 

90
would result in an instantaneous decrease in absolute population numbers for that year, 

albeit an undetectable decrease. Thus, the action will result in a reduction of green sea 

turtle numbers. The expected mortalities will eliminate an individual’s contribution to 

future generations; thus, resulting in a reduction in reproduction. Below, we consider the 

population trends for green sea turtles and the effect that the anticipated reduction in 

numbers and reproduction has on the survival of the species. 

The two largest nesting populations are found at Tortuguero, on the Caribbean coast of 

Costa Rica, and Raine Island, on the Great Barrier Reef in Australia, where an annual 

average of 22,500 and 18,000 females nest per season, respectively. In the U.S., green 

turtles nest primarily along the central and southeast coast of Florida; present estimates 

range from 200-1,100 females nesting annually. The total population of green turtles is 

not known, but nesting activity in Florida and the major Caribbean nesting beach at 

Tortuguero, Costa Rica, has increased over the long-term and populations are stable or 

increasing. 

All life stages are important to the survival and recovery of the species; however, it is 

important to note that individuals of one life stage are not equivalent to those of other life 

stages. Individuals in earlier life stages are subject to many potential sources of 

mortality, both natural and human-induced, prior to reaching sexual maturity. Only a 

fraction of pelagic juveniles are ever expected to contribute to the population through 

reproduction, and thus are not as valuable to the population as a breeding age adult. 

Sea turtle mortality resulting from vessel interactions or spilled oil could result in the loss 

of reproductive value of an adult turtle. The loss of 7-8 adult females over the 40-year 

lifetime of the proposed action (1 female every 5-6 years), could preclude the production 

of thousands of eggs and hatchlings, of which a small percentage are expected to survive 

to sexual maturity. However, the proportional change in overall survival of green sea 

turtles from the loss of one female every 5-6 years would be insignificant. The number 

of younger sea turtles recruiting into the adult or subadult population and their future 

potential reproductive value would quickly exceed the incidental take of these individuals 

and its future reproductive value. 

The 51 takes over the 40-year lifetime of the proposed action is not expected to result in 

any detectable change in the population’s growth rate. Recruitment into the population is 

expected to replace these individuals, allowing the species to quickly recover from this 

relatively small number of deaths annually. The removal of a low number of individuals 

of these species is not expected to appreciably reduce the likelihood of the survival of 

green sea turtles in the wild. 

Summary of Green Sea Turtle Survival 

Based on the above analysis, we believe that the lethal and non-lethal takes of green sea 

turtles associated with the proposed action are not reasonably expected to cause, directly 

or indirectly, an appreciable reduction in the likelihood of survival of green sea turtles in 

the wild. 

91
Likelihood of Hawksbill Sea Turtle Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of hawksbill sea turtles will 

not appreciably increase the risk of extinction of this species in the wild. 

The non-lethal take of 1 individual by vessel strike and 1 individual by oil spill over the 

40-year lifetime of the action could potentially result in short-term affects on individuals. 

Sea turtles are generally known to not avoid oil slicks, and are often found near oil and 

gas operations. We anticipate 1 individual may be struck and killed by a vessel impact 

over the 40-year lifetime of the proposed action. The numbers of non-lethal and lethal 

takes of hawksbill sea turtles are low, a total of 3 over the 40 lifetime of the action. 

Because such a small number of animals are expected to be taken (1 individual every 

13.3 years, on average), no reduction in the distribution of hawksbill sea turtles is 

expected from lethal and non-lethal takes. 

The non-lethal take of 1 individual by vessel strike and 1 individual by oil spills (tarball 

ingestion) over the 40-year lifetime of the action could potentially result in short-term 

effects in the fitness of individuals. Adult foraging habitat, which may or may not 

overlap with developmental habitat, is typically coral reefs, although other hard-bottom 

communities and occasionally mangrove-fringed bays may be occupied. Although 

hawksbills may occasionally be expected to be found in the action area, this species’ 

habitats are found mainly along peninsular Florida and Mexico, and they are expected to 

be of low density and rare in the action area. Despite their rarity, 1 turtle may have a risk 

of ingesting tarballs due to the persistence of tarballs after a slick has dissipated. Nonlethal takes by vessel strike are not expected to have any measurable impact on the 

reproduction or numbers of hawksbill sea turtles. The reaction to and injury incurred 

from vessel impacts would be dependent on the operational speed of the vessel, depth of 

the turtle, bow type, and other factors. The non-lethal takes may range from startle 

reactions to minor injury, and turtles are expected to recover within an appropriate 

amount of time, depending on the magnitude of impact. Although the range of impacts 

of non-lethal takes is variable, all impacts are expected to be fully recoverable from such 

that no reduction in reproduction or numbers of hawksbill sea turtles are anticipated. 

The lethal take of one hawksbill by vessel strike is expected over the 40-year lifetime of 

the proposed action. Thus, the action will result in a reduction of hawksbill numbers. If 

the animal lethally taken were a female, a reduction in reproduction may be incurred. 

Below, we consider the population trends for hawksbill sea turtles and the effect that the 

anticipated reduction in numbers and reproduction has on the survival of the species. 

Hawksbills are solitary nesters and, thus, determining population trends or estimates on 

nesting beaches is difficult. Hawksbills are not common in the action area, but solitary 

turtles have been occasionally sighted in shallow, coastal waters. Within the continental 

U.S., nesting is restricted to the southeast coast of Florida and the Florida Keys, but 

nesting is rare in these areas. The largest populations of hawksbills are found in the 

Caribbean, the Republic of Seychelles, Indonesia, and Australia. The most significant 

nesting within the U.S. occurs in Puerto Rico and the U.S. Virgin Islands, specifically on 

92
Mona Island and Buck Island, respectively. Each year, about 500-1000 hawksbill nests 

are laid on Mona Island, Puerto Rico (Díez and van Dam 2006) and another 100-150 

nests on Buck Island Reef National Monument off St. Croix in the U.S. Virgin Islands. 

Nesting also occurs on other beaches in St. Croix and on St. John, St. Thomas, Culebra 

Island, Vieques Island, and mainland Puerto Rico. In addition to nesting beaches in the 

U.S. Caribbean, hawksbills nest at numerous other sites throughout the Caribbean, with 

the majority of nesting occurring in Mexico and Cuba. In Mexico, about 2,800 

hawksbills nest in Campeche, Yucatán, and Quintana Roo each year (Spotila 2004). Lutz 

et al. (2003) estimate the number of adult hawksbills living in the Caribbean today is 

27,000. In the Pacific, the largest nesting population of hawksbills appears to occur in 

Australia with approximately 2,000 hawksbills nest on the northwest coast of Australia 

and about 6,000 to 8,000 off the Great Barrier Reef each year (Spotila 2004). 

In spite of their low potential to be affected in the action area, a potential exists for one 

hawksbill sea turtle to be lethally taken over the 40-year lifetime of the proposed action. 

There is a 50% probability the individual could be an immature or mature female sea 

turtle. Even if a single female hawksbill sea turtle were removed from the population, the 

effects on the size and reproductive value to the population would not be detectable. 

Summary of Hawksbill Sea Turtle Survival 

Based on the above analysis, we believe that the lethal and non-lethal takes of hawksbill 

sea turtles associated with the proposed action are not reasonably expected to cause, 

directly or indirectly, an appreciable reduction in the likelihood of survival of hawksbill 

sea turtles in the wild. 

Likelihood of Gulf Sturgeon Survival

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of Gulf sturgeon will not 

appreciably increase the risk of extinction of this species in the wild. 

Although some lethal takes from oil spills are expected, oil floats and is expected to 

impact the environment for short periods of time; therefore, oil spills are not expected to 

result in any reduction in the distribution of Gulf sturgeon. Takes are expected to occur 

in the GOM, rather than rivers, and are therefore potentially expected to effect 

reproductive fish. Two individual Gulf sturgeon are anticipated to be lethally taken by 

oil spills over the 40-year lifetime of the proposed action; thus, the action will result in a 

reduction in numbers and reproduction for Gulf sturgeon. Below, we consider the 

population trends for Gulf sturgeon and the effect that the anticipated reduction in 

numbers and reproduction has on the survival of the species. 

 

Gulf sturgeon occur in most major tributaries of the northeastern GOM, from the 

Mississippi River east to Florida’s Suwannee River, and in the central and eastern 

nearshore Gulf waters as far south as Charlotte Harbor, Florida. While little is known 

about the abundance of Gulf sturgeon throughout most of its range, population estimates 

have been calculated for the Apalachicola (115 individuals), Choctawhatchee (2,000 to 

3,000 individuals), and Suwannee Rivers (7,650 individuals). Genetic studies show that 

93
Gulf sturgeon exhibit river-specific fidelity. Based on analysis of oil spills occurring 

within the range of Gulf sturgeon, the two lethal takes of Gulf sturgeon expected would 

occur for fish native to Lake Pontchartrain/Pearl River subpopulation, for which no 

population numbers have been conducted. 

Although no population estimates are available for the Lake Pontchartrain/Pearl River 

subpopulation, the range-wide decline in the Gulf sturgeon population appears to have 

been arrested primarily by closing the state fisheries in the 1980s. However, because the 

Gulf sturgeon is a long-lived, late maturing animal, it is probable that the species requires 

numerous generations to achieve long-term population stability assuming that adequate 

habitat is available. For instance, in the Suwannee River, where sub-population numbers 

appear to be the greatest (approximately 7,600 individuals), only 30 to 90 females spawn 

in any given year. Because the affected fish are expected to be taken in the GOM, and 

not in spawning rivers, the two sturgeon takes are expected to be adults. The removal of 

two adults could potentially affect the number of reproductive individuals available in 

that year the take occurred. Factors to consider include the sex of the animals taken, and 

if females, whether or not the individuals were spawning that year. However, due to the 

low number of expected takes, we believe the expected removal of two individuals by oil 

spill over 40 years of the proposed action will not result in any detectable effect on the 

population, and this species will continue to persist in the wild. 

Summary of Gulf Sturgeon Survival 

Based on the above analysis, we believe that the lethal takes of Gulf sturgeon associated 

with the proposed action are not reasonably expected to cause, directly or indirectly, an 

appreciable reduction in the likelihood of survival of Gulf sturgeon in the wild. 

Likelihood of Sperm Whale Survival 

In the following analysis, we demonstrate that although some short-term reduction in 

numbers and reproduction is expected, the anticipated take of sperm whales will not 

appreciably increase the risk of extinction of this species in the wild. 

Harassment of sperm whales resulting from seismic surveys is not expected to result in a 

reduction of numbers, reproduction, or distribution of sperm whales in the wild. 

Although historical abundances of sperm whales in the GOM are unavailable, recent 

abundance estimates based on surveys (Mullin and Fulling 2003) indicated that the sperm 

whale population in the GOM is stable (1,349 whales). Estimates of the global sperm 

whale population indicate numbers exceeding at least 200,000 individuals is likely and 

the population appears to be recovering from the large numbers of individuals removed 

by whaling, the primary threat resulting in this species’ listing. The GOM population is 

comprised of mostly a female population and calves. The effects of oil on sperm whales 

in this area could be on females and immature animals of either sex. Any exposure to 

spilled oil is expected to be limited to temporary exposure to volatile compounds in the 

form of oil at the surface or vapors. Although some temporary avoidance of a spill may 

result, no reduction in the distribution of sperm whales would result. The non-lethal 

takes from oil exposure are not expected to result in any reduction in numbers of 

reproduction of sperm whales. 

94
Summary of Sperm Whale Survival 

Based on the above analysis, we believe that the non-lethal takes of sperm whales 

associated with the proposed action are not reasonably expected to cause, directly or 

indirectly, an appreciable reduction in the likelihood of survival of sperm whales in the 

wild. 

9.2. Effects of the Action on the Likelihood of Recovery in the Wild 

The above analysis on the effects of the action on the likelihood of each species’ survival 

in the wild considered the current status of each species and effects of the numbers of 

lethal and/or non-lethal takes anticipated for each species. For species in which no 

reductions in the species numbers, reproduction, or distribution were found, we 

concluded no change in the species survival would be incurred. For species in which the 

analysis concluded expected reductions in the number, reproduction, or distribution of the 

species, the effect of those reductions was analyzed to determine whether those 

reductions would appreciable reduce the likely survival of the species. Although no 

appreciable change in distribution was concluded for any species, we concluded lethal 

takes would result in an instantaneous reduction in absolute population numbers that may 

also reduce reproduction, but the short-term reductions are not expected to appreciable 

reduce the likelihood of survival of any species in the wild. The following analysis 

considers the effects of the take on the likelihood of recovery in the wild. We consider 

the recovery objectives in the recovery plans prepared for each species that relate to 

population numbers or reproduction that may be affected by any reductions in the 

numbers, reproduction, or distribution resulting from the take of each species. 

Likelihood of Loggerhead Sea Turtle Recovery 

The Atlantic recovery plan for the United States population of the loggerhead sea turtles 

(NMFS and USFWS 1991a), herein incorporated by reference, lists the following 

relevant recovery objective over a period of 25 continuous years: 

• The adult female population in Florida is increasing and in North Carolina, 

South Carolina, and Georgia, it has returned to pre-listing nesting levels (NC 

= 800 nests/season; SC = 10,000 nests/season; GA = 2,000 nests/season). 

The 161 lethal takes of loggerhead sea turtles over a period of 40-years (approximately 4 

lethal takes annually) will result in a reduction in overall population numbers in any 

given year. One-quarter of these takes are expected to be adult females and may effect 

reproduction (approximately 1 adult female every 1.6 years or 66 adult females over 40 

years of the proposed action). We have already determined these takes are not likely to 

reduce population numbers over time due to current population sizes and expected 

recruitment. Non-lethal takes of loggerhead sea turtles by vessel strikes or oil spill (8.7 

non-lethal takes annually, on average, or 349 non-lethal takes over a period of 40 years) 

will not affect the adult female nesting population or number of nests per nesting season. 

When considering no anticipated effects on nesting and the fact that oil spills associated 

with the proposed action will not affect any of the nesting beaches listed in the recovery 

objective above, non-lethal takes will not result in an appreciable reduction in the 

likelihood of loggerhead sea turtle recovery in the wild. 

95
Likelihood of Leatherback Sea Turtle Recovery 

The Atlantic recovery plan for the United States population of the leatherback sea turtles 

(NMFS and USFWS 1992), herein incorporated by reference, lists the following relevant 

recovery objective;

• The adult female population increases over the next 25 years, as evidenced by 

as statistically significant trend in the number of nests at Culebra, Puerto 

Rico, St. Croix, USVI, and along the east coast of Florida. 

The lethal removal of 13 individuals (one individual every 3.1 years) will result in the 

instantaneous reduction in overall population numbers in any given year of the take 

occurring. Six of these takes are expected to be adult females. We have already 

determined these takes are not likely to reduce population numbers over time due to 

current population sizes and expected recruitment. The effects of this reduction in 

population numbers are not reasonably expected to cause, directly or indirectly, an 

appreciable reduction in the likelihood of leatherback sea turtle recovery in the wild. 

Takes of leatherback sea turtles by vessel strikes or oil spill are not anticipated to reduce 

the adult female nesting population or number of nests. Accidental oil spills in the GOM 

will not affect any of the nesting beaches listed in the recovery objective above. 

Likelihood of Kemp’s Ridley Sea Turtle Recovery 

The recovery plan for Kemp’s ridley sea turtles (USFWS and NMFS 1992), herein 

incorporated by reference, lists the following relevant recovery objective: 

• Attain a population of at least 10,000 females nesting in a season. 

The lethal removal of 18 individuals (approximately one lethal take every 2.2 years) will 

result in the instantaneous reduction in overall population numbers in any given year of a 

take occurring. About 1 adult female every 10 years is expected to be lethally taken, or 

approximately 4 females over the 40-year lifetime of the lease sales. We have already 

determined these takes are not likely to reduce population numbers over time due to 

current population sizes and expected recruitment. Takes of Kemps ridley sea turtles by 

vessel strikes or oil spill will not affect the number of nesting females in any given 

nesting season. Thus, the proposed action will not result in an appreciable reduction in 

the likelihood of Kemp’s ridley sea turtle recovery in the wild. 

Likelihood of Green Sea Turtle Recovery 

The Atlantic recovery plan for the population of green sea turtles (NMFS and USFWS 

1991b), herein incorporated by reference, lists the following relevant recovery objectives 

over a period of 25 continuous years: 

• The level of nesting in Florida has increased to an average of 5,000 nests per 

year for at least 6 years. 

• A reduction in stage class mortality is reflected in higher counts of 

individuals on foraging grounds. 

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The 51 lethal takes of green sea turtles over a period of 40 years (approximately 1.3 lethal 

takes annually, on average) will result in the instantaneous reduction in overall 

population numbers in any given year. We have already determined these takes are not 

likely to reduce population numbers over time due to current population sizes and 

expected recruitment. About 11 of these takes are expected to be adult females 

(approximately 1 adult female and 1 juvenile every 3.6 years). No age class will be more 

at risk than another, and the removal of 1 juvenile every 1.3 years is not anticipated to 

result in any detectable effects on counts of juveniles on foraging grounds. Takes of 

green sea turtles by vessel strikes or oil spill will not affect either of the above recovery 

objectives, since neither the level of nesting nor age class mortality effects will result. 

Thus, the proposed action will not result in an appreciable reduction in the likelihood of 

green sea turtle recovery in the wild. 

Likelihood of Hawksbill Sea Turtle Recovery 

The recovery plan for the population of the hawksbill sea turtles (NMFS and USFWS 

1993), herein incorporated by reference, lists the following relevant recovery objectives 

over a period of 25 continuous years: 

• The adult female population is increasing, as evidenced by a 

statistically significant trend in the annual number of nests at five index 

beaches, including Mona Island and BIRNM. 

• The numbers of adults, subadults, and juveniles are increasing, as 

evidenced by a statistically significant trend on at least five key foraging 

areas within Puerto Rico, USVI, and Florida. 

We have already determined the small number of takes (1 lethal and two non-lethal) are 

not likely to reduce population numbers over time due to current population sizes and 

expected recruitment. The effect of the small number of takes over 40 years will not 

affect either of the above recovery objectives. The take of hawksbill sea turtles is not 

anticipated to result in an appreciable reduction in the likelihood of hawksbill sea turtle 

recovery in the wild. 

Likelihood of Gulf Sturgeon Recovery 

The recovery plan for the Gulf sturgeon (USFWS et al. 1995), herein incorporated by 

reference, lists the following relevant recovery objective: 

• Defining a self-sustaining population as one where the average rate (over a 

12-year period) of natural recruitment is at least equal to the average 

mortality rate. 

The incidental take of two Gulf sturgeon over the 40-year life of the proposed action, 

even if occurring in the same year, is not expected to change the population dynamics of 

the population. Although there is a chance the individuals taken may be reproductive 

females, the effects of this small reduction in numbers and reproduction is not anticipated 

to affect the natural recruitment of individuals into the population, and these mortalities 

97
are expected to be replaced through recruitment such that this recovery objective is not 

impeded. The effect of the lethal take of two individuals over 40 years is not anticipated 

to result in an appreciable reduction in the likelihood of Gulf sturgeon recovery in the 

wild. 

Likelihood of Sperm Whale Recovery

Although a final recovery plan has not been prepared for sperm whales, a draft plan was 

recently updated that identifies the following relevant recovery criteria for sperm whales: 

• A probability of extinction of <1 percent in 100 years, achieved in part by a 

stable or increasing population for at least 80 years (or 3 generations). 

No lethal takes of sperm are anticipated from this action; therefore, the non-lethal take of 

11 sperm whales will not result in an appreciable reduction in the likelihood of sperm 

whale recovery in the wild. 

9.3 Synthesis of Likelihood of Survival and Recovery in the Wild 

Conclusions for Sea Turtles 

The proposed lease sales will not appreciably reduce the likelihood of the survival and 

recovery in the wild of any of the five species of sea turtles considered in this biological 

opinion. We conclude that the anticipated reduction in numbers by take of sea turtles by 

vessel strikes and oil spills associated with the proposed action, when evaluated in the 

context of each species’ status, the environmental baseline, and the cumulative effects, 

are not expected jeopardize the continued existence of loggerhead, leatherback, Kemp’s 

ridley, green, or hawksbill sea turtles. 

Conclusions for Gulf Sturgeon 

The proposed lease sales will not appreciably reduce the likelihood of the survival and 

recovery of Gulf sturgeon. We conclude that the anticipated reduction in numbers by 

take of Gulf sturgeon by oil spills associated with the proposed action, when evaluated in 

the context of the species’ status, the environmental baseline, and the cumulative effects, 

will not affect Gulf sturgeon in a way that reduces the number of fish born in a particular 

year (i.e., a specific age-class), the reproductive success of adults, or the number of 

young annually recruited into the adult breeding population. It is our opinion the 

proposed action will not jeopardize the continued existence of Gulf sturgeon. 

Conclusions for Sperm Whales 

The proposed lease sales will not appreciably reduce the likelihood of the survival and 

recovery of sperm whales. We conclude that the anticipated reduction in numbers by 

take of sperm whales by oil spills associated with the proposed action, when evaluated in 

the context of the species’ status, the environmental baseline, and the cumulative effects, 

will not jeopardize the continued existence of sperm whales. 

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10 CONCLUSION 

We have analyzed the best available data, the current status of the species, environmental 

baseline, effects of the proposed action, and cumulative effects to determine whether the 

proposed action is likely to jeopardize the continued existence of any sea turtle species, 

Gulf sturgeon or sperm whales. The proposed action will not appreciably reduce the 

likelihood of survival and recovery of the listed species considered in this biological 

opinion. After reviewing the status of leatherback, loggerhead, green, hawksbill, and 

Kemp’s ridley sea turtles; the threatened Gulf sturgeon; endangered sperm whales, and 

analyzing the synthesis of the environmental baseline, the effects of the proposed action, 

and the cumulative effects, it is the biological opinion of NMFS that implementation of 

the proposed action described in this biological opinion is not likely to jeopardize the 

continued existence of these species.

11 INCIDENTAL TAKE STATEMENT (ITS) 

Section 9 of the ESA and protective regulations issued pursuant to section 4(d) of the 

ESA prohibit the take of endangered and threatened species, respectively, without a 

special exemption. Take is defined as to harass, harm, pursue, hunt, shoot, wound, kill, 

trap, capture or collect, or attempt to engage in any such conduct. Incidental take is 

defined as take that is incidental to, and not the purpose of, the carrying out of an 

otherwise lawful activity. Under the terms of section 7(b)(4) and section 7(o)(2), taking 

that is incidental to and not intended as part of the agency action is not considered to be 

prohibited taking under the ESA provided that such taking is in compliance with the 

RPMs and terms and conditions of the ITS. 

Section 7(b)(4)(c) of the ESA specifies that in order to provide an incidental take 

statement for an endangered or threatened species of marine mammal, the taking must be 

authorized under section 101(a)(5) of the MMPA. Since no incidental take of listed 

marine mammals is expected or has been authorized under section 101(a)(5) of the 

MMPA, no statement on incidental take of endangered whales is provided and no take is 

authorized. Nevertheless, MMS must immediately notify (within 24 hours, if 

communication is possible) the NMFS’ Office of Protected Resources should a take of a 

listed marine mammal occur. 

Take of Sperm Whales

Sperm whales within the action area are likely to be adversely affected by seismic 

activities. Seismic activities are likely to disrupt the normal behavior of marine mammals 

but measures included in NTL No. 2007-G02 should reduce the impact of that disruption 

so that it does not rise above the level of harassment (i.e., injury or mortality is not 

anticipated). Any vessel collisions with sperm whales are likely to severely harm or kill 

the animal but measures included in NTL No. 2007-G04 should reduce the risk of 

collision with sperm whales to a discountable level. However, NMFS is not including an 

incidental take statement for the incidental take of whale species because the take of 

marine mammals has not been authorized under section 101(a)(5)(A) of the Marine 

99
Mammal Protection Act (MMPA) and/or its 1994 amendments (See ESA section 

7(b)(4)(C)). 

On December 26, 2002, the MMS submitted a request for 5-year regulations under the 

MMPA for the taking, by harassment, of sperm whales incidental to the oil and gas 

industry’s seismic surveys to discover oil and gas deposits offshore in the GOM. NOAA 

Fisheries published an Advance Notice of Proposed Rulemaking regarding the small take 

authorization on March 3, 2003 (68 FR 9991). Following issuance of such regulations 

under the MMPA, NMFS will amend this opinion to include any authorized incidental 

take of sperm whales, as may be appropriate at that time. 

Take of Sea Turtles Resulting from Vessel Strikes

NMFS expects impacts to sea turtles in the action area as a result of OCS oil and gas 

leasing activities. Based on stranding records, incidental captures during recreational and 

commercial fishing operations, scientific surveys, and historical data, the five species of 

sea turtles are known to occur in GOM waters in and around the action area. The vessel 

strike avoidance requirements (NTL No. 2003-G10) will appreciably reduce the numbers 

of sea turtles that may be incidentally taken from routine offshore vessel operations 

associated with the proposed action; however, the available information on the 

relationship between these species and OCS oil and gas activities indicates that sea turtles 

may be killed or injured by vessel strikes as a result of the proposed action. Therefore, 

pursuant to section 7(b)(4) of the ESA, NMFS anticipates incidental take as follows: 

• 119 lethal (2.9 individuals annually, on average) and 238 non-lethal takes 

(5.9 individuals annually, on average) of loggerhead sea turtles over the 40-

year lifetime of the proposed action. 

• 10 lethal takes (1 individual every 4 years, on average) and 21 non-lethal 

takes (1 individual every 1.9 years, on average) of leatherback sea turtles 

over the 40-year lifetime of the proposed action. 

• 13 lethal takes (1 individual every 3 years, on average) and 26 non-lethal 

takes (1 individual every 1.5 years, on average) of Kemp’s ridley sea turtles 

over the 40-year lifetime of the proposed action. 

• 38 lethal takes (1 individual every 1.1 years, on average) and 76 non-lethal 

takes (1.9 individuals annually, on average) of green sea turtles over the 40-

year lifetime of the proposed action. 

• 1 lethal and 1 non-lethal take of a hawksbill sea turtle over the 40-year 

lifetime of the proposed action. 

If the actual incidental take exceeds this level, MMS must immediately reinitiate formal 

consultation. 

100
Takes of Listed Species Resulting from Spilled Oil 

NMFS believes that a small number of listed species will experience adverse effects as 

the result of exposure to a major oil spill or ingestion of accidentally spilled oil over the 

lifetime of the action. Spilled oil resulting from the proposed action could take up to 42 

lethal and 111 non-lethal takes of loggerheads; 2 lethal and 7 non-lethal takes of a 

leatherback sea turtles; 9 lethal and 16 non-lethal takes of Kemp’s ridley sea turtles; 13 

lethal and 36 non-lethal take of green sea turtles; 2 lethal takes of Gulf sturgeon; and 11 

non-lethal takes of sperm whales over the 40-year lifetime of the proposed lease sales. 

However, NMFS is not including an incidental take statement for the incidental take of 

listed species due to oil exposure. Incidental take, as defined at 50 CFR 402.02, refers 

only to takings that result from an otherwise lawful activity. The Clean Water Act (33 

USC 1251 et seq.) as amended by the Oil Pollution Act of 1990 (33 USC 2701 et seq.) 

prohibits discharges of harmful quantities of oil, as defined at 40 CFR 110.3, into waters 

of the United States. Therefore, even though this biological opinion has considered the 

effects on listed species by oil spills that may result from the proposed action, those 

takings that would result from an unlawful activity (i.e., oil spills) are not specified in this 

Incidental Take Statement and have no protective coverage under section 7(o)(2) of the 

ESA. 

11.1 Effect of the Take 

NMFS believes that the aforementioned level of anticipated take (lethal, or non-lethal) is 

not likely to appreciably reduce the likelihood of the survival and recovery of sperm 

whales; leatherback, green, hawksbill, Kemp’s ridley, and loggerhead sea turtles; and 

Gulf sturgeon in the wild by reducing their reproduction, numbers, or distribution. 

11.3 Reasonable and Prudent Measures (RPMs) 

Section 7(b)(4) of the ESA requires NMFS to issue a statement specifying the impact of 

any incidental taking to any agency whose proposed action is found to comply with 

section 7(a)(2) of the ESA and whose proposed action may incidentally take individuals 

of listed species. It also states that RPMs necessary and appropriate to minimize impacts, 

and terms and conditions to implement those measures, must be provided and must be 

followed to minimize those impacts. Only incidental taking by the federal agency or 

applicant that complies with the specified terms and conditions is authorized. 

The RPMs and terms and conditions are specified as required by 50 CFR 402.14 (i)(1)(ii) 

and (iv) to document the incidental take by the proposed action and to minimize the 

impact of that take on sea turtles. These measures and terms and conditions are nondiscretionary, and must be implemented by NMFS in order for the protection of section 

7(o)(2) to apply. NMFS has a continuing duty to regulate the activity covered by this 

incidental take statement. If MMS fails to adhere to the terms and conditions of the 

incidental take statement through enforceable terms, and/or fails to retain oversight to 

ensure compliance with these terms and conditions, the protective coverage of section 

7(o)(2) may lapse. 

101
NMFS has determined that the following RPMs are necessary and appropriate to 

minimize impacts of the incidental take of sea turtles from vessel operation. 

1. MMS must reduce the potential for sea turtles to be struck and injured by vessels 

operating in support of oil and gas development activities in the GOM. 

2. MMS must require the monitoring and reporting of any sea turtles struck or 

observed to have sign of vessel interaction to assess the actual level of incidental 

take in comparison with the anticipated incidental take. 

11.4 Terms and Conditions 

In order to be exempt from liability for take prohibited by section 9 of the ESA, NMFS 

must comply with the following terms and conditions, which implement the RPMs 

described above. These terms and conditions are non-discretionary. 

The following terms and conditions implement RPM No. 1. 

1. MMS must implement NMFS measures to reduce the risk of accidental vessel 

strikes with sea turtles by use of its legal authorities to ensure implementation of, 

and compliance with NTL No 2007-G04 (APPENDIX A). 

The following terms and conditions implement RPM No. 2. 

2. MMS must make information available to vessel operators concerning species 

information on sea turtles in the GOM and reporting of vessel-struck, or injured 

and dead animals. 

3. MMS must ensure that all vessel struck, or injured or dead turtles with indications 

of vessel interactions are reported to the Sea Turtle Stranding Network 

Coordinator in the nearest coastal state. Any takes of listed species shall be 

reported to the NMFS Southeast Regional Office within no more than 24 hours of 

the incident to: takereport.nmfsser@noaa.gov. If an MMS action is responsible 

for the injured or dead animals (e.g., because of a vessel strike), the MMS shall 

require the responsible parties to assist the respective salvage and stranding 

network as appropriate. Report dead or injured protected species to your local 

stranding network contacts. A list of sea turtle stranding responders is available at 

http://www.sefsc.noaa.gov/seaturtleSTSSN.jsp. A list of marine mammal 

stranding network responders for each state is available at 

http://www.nmfs.noaa.gov/pr/health/networks.htm. 

4. MMS must submit an annual report to NMFS Southeast Regional Office regarding 

the reports of vessel-struck sea turtles, and injured and dead sea turtles reported 

from oil and gas operators. Hardcopies of all annual reports will be submitted to 

the following address: 

102
Assistant Regional Administrator for Protected Resources 

National Marine Fisheries Service 

263 13th Avenue South 

St. Petersburg, FL 33701 

12 CONSERVATION RECOMMENDATIONS 

Under Section 20 of the OCSLA, the Secretary shall “. . . conduct such additional studies 

to establish environmental information as he deems necessary and shall monitor the 

human, marine, and coastal environments of such area or region in a manner designed to 

provide time-series and data trend information which can be used for comparison with 

any previously collected data for the purpose of identifying any significant changes in the 

quality and productivity of such environments, for establishing trends in the area studied 

and monitored, and for designing experiments to identify the causes of such changes.” 

Through the Environmental Studies Program (ESP), MMS conducts studies designed to 

provide information on the current status of resources of concern and notable changes, if 

any, resulting from OCS Program activities. 

Pile Driving

To better understand the cumulative effects of noise from oil and gas construction and 

development activities on the OCS, MMS should conduct a study to characterize all 

aspects of noise-producing construction and operation activities such as pile driving 

during well construction and platform installation, and of other common OCS activities. 

The study should characterize both specific sources of noise from MMS-permitted 

actions, as well as ambient noise measurements on the OCS. Major noise-producing 

activities should be identified and measurements of noise from these activities should be 

recorded and reported in appropriate units of measurement to estimate the acoustic 

footprint of the activities, duration, frequency, and relative contribution to ambient noise 

levels in the GOM. Methodologies of field measurements should be should be 

coordinated with NMFS personnel. Such data would help quantify the relative 

contribution of pile driving on ambient noise levels, compare to other known sources, and 

conduct cumulative impact analyses in the GOM. Following completion of such a study, 

MMS should hold a joint MMS/NMFS workshop with industry representatives to 

cooperatively discuss the results of the study and identify any technology- or methodbased recommendations to reduce ambient noise in the marine environment, and any 

other future actions that may be necessary. 

Observer Programs 

MMS should work cooperatively with NMFS to address existing protected species 

observer issues in the GOM. Observers are currently required for geophysical and 

geological exploration and the explosive removal of offshore structures. Some current 

issues involve standard protocols passive acoustic monitoring, observer qualifications and 

training, standard reporting formats, and improvement in communicating with observers 

companies regarding the intent and protocols to be followed for protected species 

mitigation. 

103
Marine Debris 

MMS should continue to work with NMFS and the Offshore Operators Committee to 

provide informational materials to the offshore oil and gas workers, require annual 

training, and continue to develop best management practices to reduce the release of 

debris into the marine environment. MMS should work with NMFS to update the Marine 

Debris NTL 2003-G11, as appropriate. 

Protected Species Workshops 

On June 15-16, 1999, MMS hosted a Marine Protected Species Workshop in New 

Orleans, LA. MMS, in concert with appropriate agencies and with assistance in funding 

by industry where possible, should continue efforts in supporting work to carry out the 

recommendations of that workshop panel. MMS should continue its support of research 

to determine effects of OCS related activities on protected species, other marine fauna, 

and the environment, and present the results at its information transfer meetings. 

13 REINITIATION OF CONSULTATION 

This concludes formal consultation on the CMPR fishery. As provided in 50 CFR 

402.16, reinitiation of formal consultation is required if discretionary federal agency 

involvement or control over the action has been retained (or is authorized by law) and if: 

(1) The amount or extent of the taking specified in the incidental take statement is 

exceeded; (2) new information reveals effects of the action that may affect listed species 

or critical habitat (when designated) in a manner or to an extent not previously 

considered; (3) the identified action is subsequently modified in a manner that causes an 

effect to listed species or critical habitat that was not considered in the biological opinion; 

or (4) a new species is listed or critical habitat designated that may be affected by the 

identified action. In instances where the amount or extent of incidental take is exceeded, 

MMS must immediately request reinitiation of formal consultation. 

104
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APPENDICES 

APPENDIX A. IMPLEMENTATION OF SEISMIC SURVEY MITIGAITON 

MEASURES AND PROTECTED SPECIES OBSERVER PROGRAM (NTL 2007-

G02). 

APPENDIX B. VESSEL STRIKE AVOIDANCE AND INJURED/DEAD 

PROTECTED SPECIES REPORTING (NTL 2007-G04). 

APPENDIX C. MARINE TRASH AND DEBRIS AWARENESS AND 

ELIMINATION ((NTL 2007-G03). 

127
OMB Control Number: 1010-0154 

OMB Expiration Date: February 28, 2010 

UNITED STATES DEPARTMENT OF THE INTERIOR 

MINERALS MANAGEMENT SERVICE (MMS) 

GULF OF MEXICO (GOM) OCS REGION

NTL No. 2007-G02 Effective Date: February 7, 2007 

NOTICE TO LESSEES AND OPERATORS (NTL) OF FEDERAL OIL, GAS, AND 

SULPHUR LEASES IN THE OUTER CONTINENTAL SHELF, 

GULF OF MEXICO OCS REGION 

Implementation of Seismic Survey Mitigation Measures and

Protected Species Observer Program

This NTL supersedes and replaces NTL No. 2004-G01. It does not introduce any new types of 

mitigation measures; however, it clarifies how you should implement seismic survey mitigation 

measures, including ramp-up procedures, the use of a minimum sound source, airgun testing and 

protected species observation and reporting. The measures contained herein apply to all on-lease 

surveys you conduct under 30 CFR 250 and all off-lease surveys you conduct under 30 CFR 251. 

Background 

The use of an airgun or airgun arrays while conducting seismic operations may have an impact 

on marine wildlife, including marine mammals and sea turtles. Some marine mammals, such as 

the sperm whale (Physeter macrocephalus), and all sea turtles that inhabit the GOM are 

protected under the Endangered Species Act (ESA). All marine mammals are protected under 

the Marine Mammal Protection Act (MMPA). 

In order to protect marine mammals and sea turtles during seismic operations, the National 

Marine Fisheries Service (NMFS) requires seismic operators to use ramp-up and visual 

observation procedures when conducting seismic surveys. Procedures for ramp-up, protected 

species observer training, visual monitoring and reporting are described in detail in this NTL. 

These mitigation measures apply to geophysical activities conducted under lease terms, for all 

seismic survey operations conducted in waters deeper than 200 meters (656 feet) throughout the 

GOM and, in the GOM waters east of 88.0° W. longitude, for all seismic survey operations 

conducted regardless of water depth. Performance of these mitigation measures is also a 

condition of the approval of applications for geophysical permits. You must demonstrate your 

compliance with these mitigation measures by submitting to MMS certain reports detailed in this 

NTL. 

Definitions 

Terms used in this NTL have the following meanings: 
1. Airgun means a device that releases compressed air into the water column, creating an 

acoustical energy pulse with the purpose of penetrating the seafloor. 

2. Ramp-up means the gradual increase in emitted sound levels from an airgun array by 

systematically turning on the full complement of an array’s airguns over a period of time. 

3. Visual monitoring means the use of trained observers to scan the ocean surface visually 

for the presence of marine mammals and sea turtles. These observers must have 

successfully completed a visual observer training program as described below. The area 

to be scanned visually includes, but is not limited to, the exclusion zone. Visual 

monitoring of an exclusion zone and adjacent waters is intended to establish and, when 

visual conditions allow, maintain a zone around the sound source and seismic vessel that 

is clear of marine mammals and sea turtles, thereby reducing or eliminating the potential 

for injury. 

4. Exclusion zone means the area at and below the sea surface within a radius of 500 meters 

surrounding the center of an airgun array and the area within the immediate vicinity of 

the survey vessel. Each survey vessel must maintain its own unique exclusion zone. 

5. Whales mean all marine mammals in the GOM except dolphins (see definition below) and 

manatees. This includes all species of baleen whales (Suborder Mysticeti), all species of 

beaked whales (Ziphius cavirostris and Mesoplodon sp.), sperm whales (Physeter 

macrocepahalus), and pygmy and dwarf sperm whales (Kogia sp.). Of the baleen whales, 

only the Bryde’s whale (Balaenoptera edeni) is expected to be present in the northern 

GOM and is considered uncommon. This species has primarily been sighted in water 

depths less than 200 m in the eastern GOM. Sightings of other baleen whale species are 

highly unlikely. 

6. Dolphins mean all marine mammal species in the Family Delphinidae. In the GOM, this 

includes, among others, killer whales, pilot whales, and all of the “dolphin” species. 

Ramp-up Procedures 

The intent of ramp-up is to warn marine mammals and sea turtles of pending seismic operations 

and to allow sufficient time for those animals to leave the immediate vicinity. Under normal 

conditions, animals sensitive to these activities are expected to move out of the area. For all 

seismic surveys, including airgun testing, use the ramp-up procedures described below to allow 

whales, other marine mammals, and sea turtles to depart the exclusion zone before seismic 

surveying begins. 

Measures to conduct ramp-up procedures during all seismic survey, including airgun testing, 

operations are as follows: 

1. Visually monitor the exclusion zone and adjacent waters for the absence of marine 

mammals and sea turtles for at least 30 minutes before initiating ramp-up procedures. If 

none are detected, you may initiate ramp-up procedures. Do not initiate ramp-up 

procedures at night or when you cannot visually monitor the exclusion zone for marine 

mammals and sea turtles if your minimum source level drops below 160 dB re 1 μPa-m 

(rms) (see measure 5). Altering the vessel’s course to shallower water depths (< 200m in 

the Central and Western Planning Areas) to circumvent ramp-up requirements of the 200 

meter isobath will be considered noncompliant. 

2. Initiate ramp-up procedures by firing a single airgun. The preferred airgun to begin with 

should be the smallest airgun, in terms of energy output (dB) and volume (in3

). 

2
3. Continue ramp-up by gradually activating additional airguns over a period of at least 20 

minutes, but no longer than 40 minutes, until the desired operating level of the airgun 

array is obtained. 

4. Immediately shut down all airguns ceasing seismic operations at any time a whale is detected 

entering or within the exclusion zone. You may recommence seismic operations and ramp-up of 

airguns only when the exclusion zone has been visually inspected for at least 30 minutes to 

ensure the absence of marine mammals and sea turtles. 

5. You may reduce the source level of the airgun array, using the same shot interval as the 

seismic survey, to maintain a minimum source level of 160 dB re 1 μPa-m (rms) for the 

duration of certain activities. By maintaining the minimum source level, you will not be 

required to conduct the 30-minute visual clearance of the exclusion zone before ramping 

back up to full output. Activities that are appropriate for maintaining the minimum 

source level are: (1) all turns between transect lines, when a survey using the full array is 

being conducted immediately prior to the turn and will be resumed immediately after the 

turn; and (2) unscheduled, unavoidable maintenance of the airgun array that requires the 

interruption of a survey to shut down the array. The survey should be resumed 

immediately after the repairs are completed. There may be other occasions when this 

practice is appropriate, but use of the minimum source level to avoid the 30-minute visual 

clearance of the exclusion zone is only for events that occur during a survey using the full 

power array. The minimum sound source level is not to be used to allow a later ramp-up 

after dark or in conditions when ramp-up would not otherwise be allowed. 

Protected Species Observer Program 

Visual Observers 

Visual observers who have completed a protected species observer training program as described 

below are required on all seismic vessels conducting operations in water depths greater than 200 

meters (656 ft) throughout the GOM. Visual observers are required on all seismic vessels 

conducting operations in OCS water depths less than 200 meters (656 ft.) in the GOM waters 

east of 88.0° W. longitude. At least two protected species visual observers will be required on 

watch aboard seismic vessels at all times during daylight hours (dawn to dusk) when seismic 

operations are being conducted, unless conditions (fog, rain, darkness) make sea surface 

observations impossible. If conditions deteriorate during daylight hours such that the sea surface 

observations are halted, visual observations must resume as soon as conditions permit. 

Operators may engage trained third party observers, may utilize crew members after training as 

observers, or may use a combination of both third party and crew observers. During these 

observations, the following guidelines shall be followed: (1) other than brief alerts to bridge 

personnel of maritime hazards, no additional duties may be assigned to the observer during 

his/her visual observation watch (if conditions warrant more vigilant look-outs when navigating 

around or near maritime hazards, additional personnel must be used to ensure that watching for 

protected species remains the primary focus of the on-watch observers), (2) no observer will be 

allowed more than 4 consecutive hours on watch as a visual observer, (3) a “break” time of no 

less than 2 hours must be allowed before an observer begins another visual monitoring watch 

rotation (break time means no assigned observational duties), and (4) no person (crew or third 

party) on watch as a visual observer will be assigned a combined watch schedule of more than 12 

hours in a 24-hour period. Due to the concentration and diligence required during visual 

observation watches, operators who choose to use trained crew members in these positions may 

3
select only those crew members who demonstrate willingness as well as ability to perform these 

duties. 

Training 

All visual observers must have completed a protected species observer training course. MMS 

will not sanction particular trainers or training programs. However, basic training criteria have 

been established and must be adhered to by any entity that offers observer training. Operators 

may utilize observers trained by third parties, may send crew for training conducted by third 

parties, or may develop their own training program. All training programs offering to fulfill the 

observer training requirement must: (1) furnish to MMS, at the address listed in this NTL, a 

course information packet that includes the name and qualifications (i.e., experience, training 

completed, or educational background) of the instructor(s), the course outline or syllabus, and 

course reference material; (2) furnish each trainee with a document stating successful completion 

of the course; and (3) provide MMS with names, affiliations, and dates of course completion of 

trainees. 

The training course must include the following elements: 

I. Brief overview of the MMPA and the ESA as they relate to seismic acquisition and

protection of marine mammals and sea turtles in the GOM, 

II. Brief overview of seismic acquisition operations in the GOM, 

III. Overview of seismic mitigation measures (NTLs) and the protected species observer 

program in the GOM, 

IV. Discussion of the role and responsibilities of the protected species observer in the GOM, 

including: 

a) Legal requirements (why you are here and what you do), 

b) Professional behavior (code of conduct), 

c) Integrity, 

d) Authority of protected species observer to call for shut-down of seismic acquisition 

operations, 

e) Assigned duties, 

 1) What can be asked of the observer, 

 2) What cannot be asked of the observer, 

f) Reporting of violations and coercion, 

V. Identification of GOM marine mammals and sea turtles, with emphasis on whales, 

VI. Cues and search methods for locating marine mammals, especially whales, and sea 

turtles, 

VII. Data collection and reporting requirements: 

a) Forms and reports to MMS via email at protectedspecies@mms.gov on the 1st and 

15th of each month, 

b) Whale in exclusion zone/shut-down report within 24 hours. 

4
Visual Monitoring Methods 

The observers on duty will look for whales, other marine mammals, and sea turtles using the 

naked eye and hand-held binoculars provided by the seismic vessel operator. The observers will 

stand watch in a suitable location that will not interfere with navigation or operation of the vessel 

and that affords the observers an optimal view of the sea surface. The observers will provide 

360o coverage surrounding the seismic vessel and will adjust their positions appropriately to 

ensure adequate coverage of the entire area. These observations must be consistent, diligent, and 

free of distractions for the duration of the watch. 

Visual monitoring will begin no less than 30 minutes prior to the beginning of ramp-up and 

continue until seismic operations cease or sighting conditions do not allow observation of the sea 

surface (e.g., fog, rain, darkness). If a marine mammal or sea turtle is observed, the observer 

should note and monitor the position (including lat./long. of vessel and relative bearing and 

estimated distance to the animal) until the animal dives or moves out of visual range of the 

observer. Make sure you continue to observe for additional animals that may surface in the area, 

as often there are numerous animals that may surface at varying time intervals. At any time a 

whale is observed within an estimated 500 meters (1,640 feet) of the sound source array 

(“exclusion zone”), whether due to the whale’s movement, the vessel’s movement, or because 

the whale surfaced inside the exclusion zone, the observer will call for the immediate shut-down 

of the seismic operation, including airgun firing (the vessel may continue on its course but all 

airgun discharges must cease). The vessel operator must comply immediately with such a call by 

an on-watch visual observer. Any disagreement or discussion should occur only after shutdown. When no marine mammals or sea turtles are sighted for at least a 30-minute period, rampup of the source array may begin. Ramp-up cannot begin unless conditions allow the sea surface 

to be visually inspected for marine mammals and sea turtles for 30 minutes prior to 

commencement of ramp-up (unless the method described in the section entitled “Experimental 

Passive Acoustic Monitoring” is used). Thus, ramp-up cannot begin after dark or in conditions 

that prohibit visual inspection (fog, rain, etc.) of the exclusion zone. Any shut-down due to a 

whale(s) sighting within the exclusion zone must be followed by a 30-minute all-clear period and 

then a standard, full ramp-up. Any shut-down for other reasons, including, but not limited to, 

mechanical or electronic failure, resulting in the cessation of the sound source for a period 

greater than 20 minutes, must also be followed by full ramp-up procedures. In recognition of 

occasional, short periods of the cessation of airgun firing for a variety of reasons, periods of 

airgun silence not exceeding 20 minutes in duration will not require ramp-up for the resumption 

of seismic operations if: (1) visual surveys are continued diligently throughout the silent period 

(requiring daylight and reasonable sighting conditions), and (2) no whales, other marine 

mammals, or sea turtles are observed in the exclusion zone. If whales, other marine mammals, 

or sea turtles are observed in the exclusion zone during the short silent period, resumption of 

seismic survey operations must be preceded by ramp-up. 

Reporting 

The importance of accurate and complete reporting of the results of the mitigation measures 

cannot be overstated. Only through diligent and careful reporting can MMS, and subsequently 

NOAA Fisheries, determine the need for and effectiveness of mitigation measures. Information 

on observer effort and seismic operations are as important as animal sighting and behavior data. 

In order to accommodate various vessels’ bridge practices and preferences, vessel operators and 

observers may design data reporting forms in whatever format they deem convenient and 

5
appropriate. Alternatively, observers or vessel operators may adopt the United Kingdom’s Joint 

Nature Conservation Committee forms (available at their website www.jncc.gov.uk). At a 

minimum, the following items should be recorded and included in reports to the MMS: 

Observer Effort Report: Prepared for each day during which seismic acquisition operations 

are conducted. Furnish an observer effort report to MMS on the 1st and the 15th of each month 

that includes: 

 

• Vessel name, 

• Observers’ names and affiliations, 

• Survey type (e.g., site, 3D, 4D), 

• MMS Permit Number (for “off-lease seismic surveys”) or OCS Lease Number (for 

“on-lease seismic surveys”), 

• Date, 

• Time and lat./long. when daily visual survey began, 

• Time and lat./long. when daily visual survey ended, 

• Average environmental conditions while on visual survey, including 

 Wind speed and direction, 

 Sea state (glassy, slight, choppy, rough or Beaufort scale), 

 Swell (low, medium, high or swell height in meters), 

Overall visibility (poor, moderate, good). 

Survey Report: Prepared for each day during which seismic acquisition operations are 

conducted and the airguns are being discharged. Furnish a survey report to MMS on the 1st and 

the 15th of each month during which operations are being conducted that includes: 

• Vessel name, 

• Survey type (e.g., site, 3D, 4D), 

• MMS Permit Number (for “off-lease seismic surveys”) or OCS Lease Number 

(for “on-lease seismic surveys”), 

• Date, 

• Time pre-ramp-up survey begins, 

• What marine mammals and sea turtles were seen during pre-ramp-up survey? 

• Time ramp-up begins, 

• Were whales seen during ramp-up? 

• Time airgun array is operating at the desired intensity, 

• What marine mammals and sea turtles were seen during survey? 

• If whales were seen, was any action taken (i.e., survey delayed, guns shut down)? 

• Reason that whales might not have been seen (e.g., swell, glare, fog), 

• Time airgun array stops firing. 

Sighting Report: Prepared for each sighting of a marine mammal (whale or dolphin) or sea 

turtle made during seismic acquisition operations. Furnish a sighting report to MMS on the 1st

and the 15th of each month during which operations are being conducted that includes: 

• Vessel name, 

• Survey type (e.g., site, 3D, 4D), 

6
• MMS Permit Number (for “off-lease seismic surveys”) or OCS Lease Number 

(for “on-lease seismic surveys”), 

• Date, 

• Time, 

• Watch status (Were you on watch or was this sighting made opportunistically by 

you or someone else?), 

• Observer or person who made the sighting, 

• Lat./long. of vessel, 

• Bearing of vessel, 

• Bearing and estimated range to animal(s) at first sighting, 

• Water depth (meters), 

• Species (or identification to lowest possible taxonomic level), 

• Certainty of identification (sure, most likely, best guess), 

• Total number of animals, 

• Number of juveniles, 

• Description (as many distinguishing features as possible of each individual seen, 

including length, shape, color and pattern, scars or marks, shape and size of 

dorsal fin, shape of head, and blow characteristics), 

• Direction of animal’s travel – compass direction, 

• Direction of animal’s travel – related to the vessel (drawing preferably), 

• Behavior (as explicit and detailed as possible; note any observed changes in 

behavior,) 

• Activity of vessel, 

• Airguns firing? (yes or no), 

• Closest distance (meters) to animals from center of airgun or airgun array 

(whether firing or not). 

Note: If this sighting was of a whale(s) within the exclusion zone that resulted in a shutdown of the airguns, include in the sighting report the observed behavior of the whale(s) before 

shut-down, the observed behavior following shut-down (specifically noting any change in 

behavior), and the length of time between shut-down and subsequent ramp-up to resume the 

seismic survey (note if seismic survey was not resumed as soon as possible following shutdown). Send this report to MMS within 24 hours of the shut-down. These sightings should 

also be included in the first regular semi-monthly report following the incident.

Additional information, important points, and comments are encouraged. All reports will be 

submitted to MMS on the 1st and the 15th of each month (with one exception noted above). 

Forms should be scanned (or data typed) and sent via email to protectedspecies@mms.gov. 

Please note that these marine mammal and sea turtle reports are in addition to any reports you 

submit under NTL No. 98-20, dated September 15, 1998, and NTL No. 2005-G07, effective July 

1, 2005, and all progress and final reports required as a condition of your geophysical permit. 

Borehole Seismic Surveys 

Borehole seismic surveys differ from surface seismic surveys in a number of ways, including the 

use of much smaller airgun arrays, having an average survey time of 12-24 hours, utilizing a 

7
sound source that is not usually moving at 4-5 knots, and requiring the capability of moving the 

receiver in the borehole between shots. Due to these differences, the following altered 

mitigations apply only to borehole seismic surveys: 

• During daylight hours, when visual observations of the exclusion zone are being 

performed as required in this NTL, borehole seismic operations will not be 

required to ramp-up for shutdowns of 30 minutes or less in duration, as long as no 

whales, other marine mammals, or sea turtles are observed in the exclusion zone 

during the shutdown. If a whale, other marine mammal, or sea turtle is sighted in 

the exclusion zone, ramp-up is required and may begin only after visual surveys 

confirm that the exclusion zone has been clear for 30 minutes. 

• During nighttime or when conditions prohibit visual observation of the exclusion 

zone, ramp-up will not be required for shutdowns of 20 minutes or less in 

duration. For borehole seismic surveys that utilize passive acoustics during 

nighttime and periods of poor visibility, ramp-up is not required for shutdowns of 

30 minutes or less. 

• Nighttime or poor visibility ramp-up is allowed only when passive acoustics are 

used to ensure that no whales are present in the exclusion zone (as for all other 

seismic surveys). Operators are strongly encouraged to acquire the survey in 

daylight hours when possible. 

• Protected species observers must be used during daylight hours, as required in this 

NTL, and may be stationed either on the source boat or on the associated drilling 

rig or platform if a clear view of the sea surface in the exclusion zone and 

adjacent waters is available. 

• All other mitigations and provisions for seismic surveys as set forth in this NTL 

will apply to borehole seismic surveys. 

• Reports should reference OCS Lease Number, Area/Block and Borehole Number. 

Experimental Passive Acoustic Monitoring 

Whales, especially sperm whales, are very vocal marine mammals, and periods of silence are 

usually short and most often occur when these animals are at the surface and may be detected 

using visual observers. However, sperm whales are at the greatest risk of potential injury from 

seismic airguns when they are submerged and under the airgun array. Passive acoustic 

monitoring appears to be very effective at detecting submerged and diving sperm whales, and 

some other marine mammal species, when they are not detectable by visual observation. MMS 

strongly encourages operators to participate in an experimental program by including passive 

acoustic monitoring as part of the protected species observer program. Inclusion of passive 

acoustic monitoring does not relieve an operator of any of the mitigations (including visual 

observations) in this NTL with the following exception: Monitoring for whales with a passive 

acoustic array by an observer proficient in its use will allow ramp-up and the subsequent start of 

a seismic survey during times of reduced visibility (darkness, fog, rain, etc.) when such ramp-up 

otherwise would not be permitted using only visual observers. If you use passive acoustic 

monitoring, include an assessment of the usefulness, effectiveness, and problems encountered 

with the use of that method of marine mammal detection in the reports described in this NTL. A 

description of the passive acoustic system, the software used, and the monitoring plan should 

also be reported to MMS at the beginning of its use. 

8
Paperwork Reduction Act 

The PRA (44 U.S.C. Chapter 35) requires us to inform you that we collect the information described in 

this NTL to ensure that you conduct operations in a manner that will not jeopardize threatened or 

endangered species or destroy or adversely modify critical habitat that has been designated for those 

species. We protect all proprietary information submitted according to the Freedom of Information Act 

and 30 CFR 250.196. An agency may not conduct or sponsor a collection of information unless it 

displays a currently valid Office of Management and Budget (OMB) control number. You are not 

obligated to respond until the OMB has approved this collection of information. We estimate the total 

hour burden to be 751 hours and the total “non-hour cost” burden to be $1,854,080. Direct comments 

regarding the burden, or any other aspect of this information collection, to the Information Collection 

Clearance Officer, Mail Stop 4230, Minerals Management Service, 1849 C Street, NW, Washington, DC 

20240. 

In addition, this NTL refers to information collection requirements under 30 CFR 250, subpart B. The 

OMB has approved all of the information collection requirements in these regulations and assigned OMB 

Control Number 1010-0151. 

Contact 

Any questions regarding this NTL should be submitted in writing to: protectedspecies@mms.gov. 

Submittals by mail may be directed to: 

Minerals Management Service 

Gulf of Mexico OCS Region 

Attention: Environmental Sciences Unit (MS 5430) 

1201 Elmwood Park Blvd. 

New Orleans, LA 70123-2394 

 [original signed by] 

Chris C. Oynes 

Regional Director 

9
OMB Control Number: 1010-0154 

OMB Expiration Date: February 28, 2010 

 

UNITED STATES DEPARTMENT OF THE INTERIOR 

MINERALS MANAGEMENT SERVICE (MMS) 

GULF OF MEXICO (GOM) OCS REGION 

NTL No. 2007-G04 Effective Date: February 7, 2007

NOTICE TO LESSEES AND OPERATORS (NTL) OF FEDERAL OIL, GAS, AND SULPHUR

LEASES IN THE OUTER CONTINENTAL SHELF, GULF OF MEXICO OCS REGION

Vessel Strike Avoidance and Injured/Dead Protected Species Reporting

The MMS is issuing this NTL pursuant to 30 CFR 250.103 and 30 CFR 250.282 to update the guidelines 

on how you should implement monitoring programs to minimize the risk of vessel strikes to protected 

species and report observations of injured or dead protected species. In lieu of a formal observer 

program, this NTL provides specific guidelines you should follow to identify and avoid injury to marine 

mammals and sea turtles. This NTL supersedes NTL 2003-G10 on this subject and applies to all existing 

and future oil and gas operations in the GOM OCS. 

Background 

The National Marine Fisheries Service (NMFS) has determined that collisions with OCS support/service 

vessels could injure or kill protected species (e.g., sperm whales, other marine mammals and sea turtles) 

in the Gulf of Mexico OCS while engaged in supporting oil and gas industry activities. NMFS 

recommends the following measures to reduce the risk associated with vessel strikes or disturbance of 

protected species. These measures apply to listed and non-listed cetaceans and sea turtles.

Protected Species Identification

Vessel crews should use a GOM reference guide that includes and helps identify the 28 species of whales 

and dolphins, 5 species of sea turtles, and the single species of manatee that might be encountered in the 

GOM OCS. 

Vessel Strike Avoidance

You should do the following in order to avoid causing injury or death to marine mammals and sea turtles: 

1. Vessel operators and crews should maintain a vigilant watch for marine mammals and sea turtles 

and slow down or stop their vessel to avoid striking protected species. 

2. When whales are sighted, maintain a distance of 100 yards (91 meters) or greater from the whale. 

If the whale is believed to be a North Atlantic right whale, you should maintain a minimum 

distance of 500 yards (457 meters) from the animal (50 CFR 2224.103). 

3. When sea turtles or small cetaceans are sighted, attempt to maintain a distance of 50 yards (45 

meters) or greater whenever possible. 

4. When cetaceans are sighted while a vessel is underway, attempt to remain parallel to the animal’s 

course. Avoid excessive speed or abrupt changes in direction until the cetacean has left the area. 
5. Reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of 

cetaceans are observed near an underway vessel when safety permits. A single cetacean at the 

surface may indicate the presence of submerged animals in the vicinity of the vessel; therefore, 

precautionary measures should always be exercised. 

6. Whales may surface in unpredictable locations or approach slowly moving vessels. When you 

sight animals in the vessel’s path or in close proximity to a moving vessel, reduce speed and shift 

the engine to neutral. Do not engage the engines until the animals are clear of the area. 

Injured/Dead Protected Species Reporting

Vessel crews must report sightings of any injured or dead protected species (marine mammals and sea 

turtles) immediately, regardless of whether the injury or death is caused by your vessel. Report marine 

mammals to the NOAA Fisheries Stranding Hotline at (305) 862-2850 and sea turtles to the NMFS 

Southeast Regional Office at (727) 824-5312. In addition, if the injury or death was caused by a collision 

with your vessel, you must notify MMS within 24 hours of the strike by email to 

protectedspecies@mms.gov. The report should include the date and location (latitude/longitude) of the 

strike, the name of the vessel involved, and the species identification or a description of the animal, if 

possible. If oil and gas industry activity is responsible for the injury or death, the responsible parties 

should remain available to assist the respective salvage and stranding network as needed.

Paperwork Reduction Act of 1995 (PRA) Statement

The PRA (44 U.S.C. Chapter 35) requires us to inform you that we collect the information described in 

this NTL to ensure that you conduct operations in a manner that will not jeopardize threatened or 

endangered species. We protect all proprietary information submitted according to the Freedom of 

Information Act and 30 CFR 250.196. An agency may not conduct or sponsor a collection of information 

unless it displays a currently valid Office of Management and Budget (OMB) Control Number. We 

estimate the hour burden to be one-half hour per report. Direct comments regarding the burden or any 

other aspect of this information collection to the Information Collection Clearance Officer, Mail Stop 

4230, Minerals Management Service, 1849 C Street, NW, Washington, DC 20240. 

In addition, this NTL refers to information collection requirements under 30 CFR 250, subpart B. OMB 

has approved all of the information collection requirements in these regulations and assigned OMB 

Control Number 1010-0151. 

Contact

Any questions regarding this NTL should be submitted in writing to: protectedspecies@mms.gov. 

[original signed by] 

 Chris C. Oynes 

 Regional Director 

2
OMB Control Number: 1010-0154 

OMB Expiration Date: February 28, 2010 

UNITED STATES DEPARTMENT OF THE INTERIOR 

MINERALS MANAGEMENT SERVICE 

GULF OF MEXICO OCS REGION

NTL No. 2007–G03 Effective Date: February 7, 2007 

 

NOTICE TO LESSEES AND OPERATORS (NTL) OF FEDERAL OIL, GAS, AND 

SULPHUR LEASES AND PIPELINE RIGHT-OF-WAY HOLDERS IN THE OUTER 

CONTINENTAL SHELF, GULF OF MEXICO OCS REGION

Marine Trash and Debris Awareness and Elimination

This NTL is being issued pursuant to 30 CFR 250.103 to provide information on the marine trash 

and debris awareness training video and slide show, and both postal and e-mail addresses for 

submitting annual training reports. This NTL supersedes and replaces NTL No. 2003-G11, 

effective June 19, 2003, on this subject and applies to all existing and future oil and gas 

operations in the Gulf of Mexico OCS. 

Background 

Marine trash and debris pose a threat to fish, marine mammals, sea turtles, and other marine 

animals; cause costly delays and repairs for commercial and recreational boating interests; 

detract from the aesthetic quality of recreational shore fronts; and increase the cost of beach and 

park maintenance. As oil and gas industry activities expand into deeper waters, the number of 

species of protected marine animals exposed to marine debris is increasing and now includes the 

sperm whale, an endangered species, as well as other marine mammals and five species of sea 

turtles. 

Since oil and gas operations in the Gulf of Mexico contribute to this chronic problem, 30 CFR 

250.300(a) and (b)(6) prohibit you from deliberately discharging containers and other similar 

materials (i.e., trash and debris) into the marine environment, and 30 CFR 250.300(c) requires 

you to make durable identification markings on equipment, tools and containers (especially 

drums), and other material. 

Furthermore, the intentional jettisoning of trash has been the subject of strict laws such as 

MARPOL-Annex V and the Marine Plastic Pollution Research and Control Act, and regulations 

imposed by various agencies including the United States Coast Guard (USCG) and the 

Environmental Protection Agency (EPA). 
 2 

These USCG and EPA regulations further require that you become more proactive in avoiding 

accidental loss of solid waste items by developing waste management plans, posting 

informational placards, manifesting trash sent to shore, and using special precautions such as 

covering outside trash bins to prevent accidental loss of solid waste. 

Therefore, you should exercise special caution when you handle and dispose of small items and 

packaging materials, particularly those made of non-biodegradable, environmentally persistent 

materials such as plastic or glass that can be lost in the marine environment and washed ashore. 

Increasing your individual workers’ awareness of the problem and emphasizing their 

responsibilities will help reduce the litter problem further and control the unintended loss of 

items such as empty buckets, hard hats, shrink wrap, strip lumber and pipe thread protectors. 

Your adherence to these requirements has reduced, if not eliminated, trash intentionally 

jettisoned into the Gulf of Mexico. However, the MMS is still concerned about the accidental 

loss of articles from structures and vessels. In some cases, this results from poor waste 

management practices (e.g., no lids or unsecured lids on waste receptacles), but in others it is 

caused by the failure of individuals to secure materials and personal belongings aboard vessels 

and facilities. To reduce further the accidental introduction of marine trash and debris into the 

Gulf of Mexico, you must immediately implement the following programs. 

Marine Trash and Debris Placards

Effective May 31, 2003, you must post placards that include each of the information text boxes 

in Appendix 1 of this NTL in prominent places on all fixed and floating production facilities that 

have sleeping or food preparation capabilities and on mobile drilling units engaged in oil and gas 

operations in the Gulf of Mexico OCS. All of the placards depicted, with the language specified, 

should be displayed on an approximately 5x8 inch format. These signs should be displayed at 

line-of-sight height at or near boat landings and heliports, in mess areas, and in the recreation or 

training or orientation area. One or more areas may be omitted if there is insufficient space. 

These notices should be referenced, and their contents explained, during any initial orientation 

given on the facility for visitors or occupants. Placards must be sturdy enough to withstand the 

local environment and must be replaced when damage or wear compromises readability.

Marine Trash and Debris Awareness Training

Effective May 31, 2003, all of your offshore employees and those contractors actively engaged 

in your offshore operations (e.g., wireline operators, contract lease operators, and maintenance or 

construction crews) must have completed marine trash and debris awareness training described 

below at least once. Thereafter, all such personnel must complete this training annually. 

The training for employees and contractors consists of two parts: (1) viewing a marine trash and 

debris training video or slide show and (2) receiving an explanation from management personnel 

from the lessee or designated lease operator that emphasizes their commitment to the message of 

this NTL. 

 .
 3 

You may obtain the marine trash and debris training video, produced by the Offshore Operators 

Committee (OOC), through the OOC website at www.offshoreoperators.com. The video is 

available in English and Spanish versions as a DVD or VHS tape. The video may also be 

downloaded directly from the website. 

Alternatively, you may fulfill this training requirement by viewing the marine trash and debris 

training slide show developed by OOC and available on the aforementioned website as a 

Microsoft PowerPoint presentation. 

Marine Trash and Debris Awareness Training and Certification Process 

Effective July 1, 2003, you should develop and be using a marine trash and debris awareness 

training and certification process that reasonably assures that the employees and contractors 

specified above are in fact trained. Your training process should include the following elements: 

1) viewing of either the video or the slide show by the personnel specified above using one 

of the following methods: 

a) attendance at periodic meetings held for this purpose; 

b) as part of several scheduled training components; 

c) web-based training with email notification; or 

d) training by a third-party contractor; 

 2) an explanation from the management that conveys the commitment of the company to 

 achieve the objectives of the trash and debris containment requirement; 

3) attendance measures (initial and annual); and 

4) recordkeeping and availability of records for inspection by MMS. 

By January 31st of each year, provide the MMS with an annual report (1–2 pages) signed by a 

company official that describes your marine trash and debris awareness training process and 

certifies that the training process has been followed for the previous calendar year. A sample 

annual report is available at the OOC website above. Send the report to: 

Mr. Herb Leedy 

Minerals Management Service 

Gulf of Mexico OCS Region 

Office of Leasing and Environment (MS 5430) 

1201 Elmwood Park Blvd. 

New Orleans, Louisiana 70123 

In lieu of mailing the report, you may send it by e-mail to trashanddebris@mms.gov. 

Paperwork Reduction Act of 1995 (PRA) Statement

The PRA (44 U.S.C. Chapter 35) requires us to inform you that we collect the information 

described in this NTL to ensure that you conduct operations in a manner that will not jeopardize 

threatened or endangered species or destroy or adversely modify critical habitat that has been 

designated for those species. We protect all proprietary information submitted according to the 

 .
 4 

Freedom of Information Act and 30 CFR 250.197. An agency may not conduct or sponsor a 

collection of information unless it displays a currently valid Office of Management and Budget 

(OMB) Control Number. We estimate the hour burden to be one-half hour per training record. 

We estimate the hour burden to be one-half hour for each annual report and certification. The 

placard postings are exempt from the PRA requirements. Direct comments regarding the burden 

or any other aspect of this information collection to the Information Collection Clearance 

Officer, Mail Stop 4230, Minerals Management Service, 1849 C Street, N.W., Washington, DC 

20240. 

In addition, this NTL refers to information collection requirements under 30 CFR 250, subparts 

B and C. The OMB has approved all of the information collection requirements in these 

regulations and assigned OMB Control Numbers 1010-0151 and 1010-0057, respectively. 

Contact 

Submit any questions regarding this NTL by e-mail to: marinedebris@mms.gov. 

 

 

 [original signed by] 

. Chris C. Oynes 

 Regional Director

 .
 5 

Appendix 1 

Marine Debris Placards 

WHAT IS MARINE DEBRIS? 

Marine debris is any object or fragment of wood, metal, glass, 

rubber, plastic, cloth, paper or any other man-made item or material 

that is lost or discarded in the marine environment. Marine debris 

may be intentionally dumped, accidentally dropped, or indirectly 

deposited. Whatever the source, marine debris is a direct result of 

human activities on land and at sea. Depending upon its 

composition, marine debris may sink to the seafloor, drift in the water 

column, or float on the surface of the sea. Certain debris, such as 

plastics, can persist for hundreds of years in the marine environment 

without decomposing. 

WARNING!

YOUR ACTIONS MAY SUBJECT YOU TO SEVERE LEGAL 

CONSEQUENCES!

The disposal and/or discharge of any solid waste anywhere in the 

marine environment (other than ground-up food particles) is strictly 

prohibited by U.S. Coast Guard and Environmental Protection 

Agency regulations. THIS INCLUDES MATERIALS OR DEBRIS 

ACCIDENTALLY LOST OVERBOARD. 

The disposal of equipment, cables, chains, containers or other 

materials into offshore waters is prohibited by the Minerals 

Management Service (30 CFR 250.300(b)(6)). THIS INCLUDES 

MATERIALS OR DEBRIS ACCIDENTALLY LOST OVERBOARD. 

 .
 6 

ATTENTION!

MARINE DEBRIS MAY CAUSE SEVERE ECOLOGICAL DAMAGE! 

Marine debris discarded or lost from offshore and coastal sources 

may injure or kill fish, marine mammals, sea turtles, seabirds and 

other wildlife. 

Thousands of marine animals, including marine mammals, sea turtles 

and seabirds, die every year from entanglement in fishing line, 

strapping bands, discarded ropes and nets and plastic six-pack rings. 

Additionally, unknown numbers of marine animals die each year from 

internal injury, intestinal blockage and starvation as a result of 

ingesting marine debris. 

Marine debris fouls boat propellers and clogs water intake ports on 

engines thereby endangering the safety of fishermen and boaters 

and resulting in heavy loss of time and money. 

Marine debris detracts from the aesthetic quality of recreational 

beaches and shorelines and increases the cost of park and beach 

maintenance. 

 .
 7 

ATTENTION! 

SECURE ALL LOOSE ARTICLES!

NOAA Fisheries now expects petroleum industry personnel to pick up 

and recover any articles lost overboard from boats and offshore 

structures as safety conditions permit. 

Protect marine animals, as well as your valuable time and money, by 

doing the following to prevent accidental loss of these items: 

Properly securing all materials, equipment and personal belongings. 

Articles such as hardhats, life vests, sunglasses, cigarette lighters, 

parts bags, buckets, shrink wrap, strip lumber, and pipe thread 

protectors become marine debris when lost overboard. 

Making sure that all trash receptacles have tight fitting lids and that 

the lids are used. 

Providing and using secure cigarette butt containers. Cigarette butts 

are one of the most common forms of marine debris. Many cigarette 

butts contain some form of plastic and do not decompose in the 

ocean. Cigarette butts pose a major threat to marine wildlife as they 

resemble food and cause gut blockages and starvation when 

ingested. 

Doing your part to eliminate marine debris. Encourage others to be 

responsible about marine debris by making suggestions to secure 

potential marine debris on your boat or structure or by participating in 

a beach cleanup. 

 .
Appendix C 

Attachment 2 

Biological Assessment & Addendum 
1

Biological Assessment 

USFWS Consultation 

Gulf of Mexico OCS Oil and Gas Lease Sales: 2007-2012 

The Proposed Actions

The Endangered Species Act of 1973 (ESA) (16 United States Code (U.S.C.) 1631 and the 

following (et seq.)), as amended (43 U.S.C. 1331 et seq.), establishes a national policy designed 

to protect and conserve threatened and endangered species and the ecosystems upon which they 

depend. The ESA is administered by the United States (U.S.) Department of the Interior 

(USDOI), U.S. Fish and Wildlife Service (FWS) and the U.S. Department of Commerce 

(USDOC), National Oceanic Atmospheric Administration (NOAA), National Marine Fisheries 

Service (NMFS). Section 7 of the ESA governs interagency cooperation and consultation. Under 

Section 7, the USDOI, Minerals Management Service (MMS) consults with both FWS and 

NMFS to ensure that activities on the Outer Continental Shelf (OCS) under MMS jurisdiction do 

not jeopardize the continued existence of threatened or endangered species and/or result in 

adverse modification or destruction of their critical habitat. 

Consultation with FWS under Section 7 of the ESA on Western Planning Area (WPA) and 

Central Planning Area (CPA) Gulf of Mexico (GOM) OCS oil and gas activities has been 

ongoing since 1979. Until recently, consultation on the EPA has always been conducted under 

the formal process because of the size and location of the lease sales, the lack of history of the oil 

and gas industry in the area, and the potential impacts to listed species from a proposed action’s 

activities. However, since oil and gas activities first began in GOM State and OCS waters, many 

changes have occurred including enactment of laws regulating the offshore industry, 

incorporation of mitigating measures, increased experience and cooperation of the industry, 

technology advancements, and studies and research on the physical environment and biological 

resources of the GOM and adjacent coastal waters and impact-producing factors (IPF’s) of the oil 

and gas activities on the environment and listed species. Therefore, MMS and FWS have 

determined that an informal consultation is sufficient for WPA Sales 204, 207, 210, 215, and 218; 

and CPA Sales 205, 206, 208, 213, 216, and 222. 

Description of the Proposed Actions

The proposed actions are 11 oil and gas lease sales in the WPA and CPA as scheduled under the 

5-Year Program for 2007-2012 and analyzed by MMS in Gulf of Mexico OCS Oil and Gas Lease 

Sales: 2007-2012, Final Environmental Impact Statement, Volumes I and II (USDOI, MMS, 

2007). Federal regulations allow for several related or similar proposals to be analyzed in one EIS 

(40 CFR 1502.4). Since the proposed lease sales in each lease sale area and their projected 

activities are very similar, MMS has prepared a single EIS for the 11 WPA and CPA lease sales 

in the proposed 5-Year Program. The EIS, from which this BA is tiered, is hereby incorporated 

by reference. 

Proposed WPA Lease Sales 204, 207, 210, 215, and 218 

The proposed WPA lease sales are Sale 204 in 2007, Sale 207 in 2008, Sale 210 in 2009, Sale 

215 in 2010, and Sale 218 in 2011. The WPA encompasses about 28.6 million acres (ac) located 

3 leagues (10 miles (mi)) offshore Texas and extends seaward to the limits of the EEZ in water 
2

depths up to 3,346 meters (m) (10,978 ft) (Figure 1-1). Each WPA proposed lease sale would 

offer for lease all unleased blocks in the WPA for oil and gas operations (Figure 1-1), with the 

following exceptions: 

(1) whole and partial blocks within the boundary of the Flower Garden Banks 

National Marine Sanctuary; and 

(2) whole and partial blocks that lie within the 1.4-nautical-mile (nmi) buffer 

zone north of the continental shelf boundary between the United States (U.S.) 

and Mexico, for Sales 204, 207, 210, and 215 only. 

The estimated amount of resources projected to be developed as a result of any one proposed 

WPA lease sale is 0.242-0.423 billion barrels of oil (BBO) and 1.644-2.647 trillion cubic feet 

(Tcf) of gas. The proposed WPA lease sales include proposed lease stipulations designed to 

reduce environmental risks and are discussed in Chapter 2.3. 

Proposed CPA Lease Sales 205, 206, 208, 213, 216, and 222 

The proposed CPA lease sales are Sale 205 in 2007, Sale 206 in 2008, Sale 208 in 2009, Sale 213 

in 2010, Sale 216 in 2011, and Sale 222 in 2012. The CPA sale area encompasses about 58.7 

million ac of the CPA’s 66.3 million ac and is located 3 nmi offshore Louisiana, Mississippi, and 

Alabama and extends seaward to the limits of the EEZ in water depths up to 3,458 m (11,345 ft) 

(Figure 1-1). Each subsequent proposed CPA sale would offer for lease all unleased blocks in the 

CPA for oil and gas operations (Figure 1-1), with the following exceptions: 

(1) blocks directly south of Florida and within 100 mi of the Florida coast (north 

of the easternmost portion of the CPA sale area as shown on Figure 1-1); 

(2) blocks under an existing Presidential withdrawal through 2012, as well as 

subject to annual congressional moratoria (southeastern portion of the CPA sale 

area as shown on Figure 1-1); 

(3) blocks that are beyond the U.S. Exclusive Economic Zone in the area known 

as the northern portion of the Eastern Gap; and 

(4) whole and partial blocks that lie within the 1.4-nmi buffer zone north of the 

continental shelf boundary between the U.S. and Mexico, for Sales 205, 206, 

208, and 213 only. 

The estimated amount of resources projected to be developed as a result of any one proposed 

CPA lease sale is 0.776-1.292 BBO and 3.236-5.229 Tcf of gas. The subsequent, proposed CPA 

lease sales include proposed lease stipulations designed to reduce environmental risks and are 

discussed in Chapter 2.4. 

Species Descriptions, Impacts and Analyses

The following endangered and threatened species are found in the proposed action area and were 

analyzed by MMS: 
3

Listed Species Texas Louisiana Mississippi Alabama 

 

Brown pelican 

(Pelecanus 

occidentalis) 

 E E E 

Bald eagle 

(Haliaeetus 

leucocephalus) 

 T T T T 

Piping plover 

(Charadrius 

melodus) 

 T, CH T, CH T, CH T, CH 

Whooping crane 

(Grus 

americana) 

 E, CH 

Alabama beach 

mouse 

(Peromyscus 

polionotus 

ammobates) 

 E, CH 

Perdido beach 

mouse 

(Peromyscus 

polionotus 

trissyllepsis)

 E, CH 

Loggerhead sea 

turtle (Caretta 

caretta) 

 T T T T 

Kemp’s ridley 

sea turtle 

(Lepidochelys 

kempii) 

 E 

BIRDS

The following coastal and marine bird species that inhabit or frequent the north-central and 

western GOM coastal areas are recognized by FWS as either endangered or threatened: piping 

plover, whooping crane, bald eagle, and brown pelican. 

Piping Plover 

The piping plover (Charadrius melodus) is a migratory shorebird that is endemic to North 

America. The piping plover breeds along shorelines in the northern Great Plains, the Great Lakes, 

and along the Atlantic Coast (Newfoundland to North Carolina). It winters on the Atlantic and 

Gulf Coasts from North Carolina to Mexico and in the Bahamas West Indies. The final rule on 

critical habitat of piping plover was published July 10, 2001; there are 20 units of critical habitat 

in western Florida south to Tampa Bay, 3 areas in Alabama, 15 in Mississippi, 7 in Louisiana, 

and 37 in Texas (66 FR 132, pp. 36037-36086). Critical wintering habitat includes the land 

between mean lower low water and any densely vegetated habitat, which is not used by the piping 

plover. It has been hypothesized that specific wintering habitat, which includes coastal sand flats 

and mud flats in close proximity to large inlets or passes, may attract the largest concentrations of 

piping plovers because of a preferred prey base and/or because the substrate coloration provides 

protection from aerial predators due to chromatic matching, or camouflage (Nicholls and 
4

Baldassarre, 1990). This species remains in a precarious state given its low population numbers, 

sparse distribution, and continued threats to habitat throughout its range. About 2,299 birds were 

located on the U.S. wintering grounds during the 2001 census; 83 percent of these were found on 

the Gulf coast. The highest numbers of wintering plovers occurred along the Texas coast (43.6%), 

with Louisiana ranked second (21.4%). Piping plovers were commonly found on mud flats 

(36.3%), sandy beaches (33.2%), and sand/salt flats (23.1%) (Haig and Ferland, 2002). They 

begin arriving on the wintering grounds in July and keep arriving through September. 

Behavioral observations of piping plovers on the wintering grounds suggest that they spend the 

majority of their time foraging. Primary prey for wintering plovers includes polychaete marine 

worms, various crustaceans, insects, and sometimes bivalve mollusks. They peck prey from on 

top of or just beneath the sediment. Foraging usually is on moist or wet sand, mud, or fine shell. 

In some cases, a mat of blue-green algae may cover this substrate. When not foraging, plovers 

can be found in aggressive encounters, roosting, preening, bathing, and moving among available 

habitat locations. The habitats used by wintering birds include beaches, mud flats, sand flats, algal 

flats, and wash over passes (areas where breaks in the sand dunes result in an inlet). Wintering 

plovers are dependent on a mosaic of habitat patches and move among these patches depending 

on local weather and tidal conditions. Reise (1985) noted some time ago that tidal flat 

communities he experimented on locally appeared dominated by predatory processes. 

Competition between organisms, including prey items of birds similar to the piping plover, 

seemed unimportant. However, he went on to say that “the interactions between the constituent 

species on the tidal flats are not chaotic by undoubtedly lack perfection [simplicity]. As a 

consequence, it is inherently impossible to arrive at clear-cut conclusions about their pattern.” In 

contrast, from a more recent perspective, Simberloff (2004) notes that “because of the 

contingency and complexity of its subject matter, community ecology has few general laws. Laws 

and models in community ecology are highly contingent, and their domain is usually very local. 

This fact does not mean that community ecology is a weak science; in fact, it is the locus of 

exciting advances, with growing mechanistic understanding of causes, patterns, and processes. 

Further, traditional community ecological research, often local, experimental, and reductionist, is 

crucial in understanding and responding to many environmental problems, including those posed 

by global changes. For both scientific and societal reasons, it is not time to abandon community 

ecology.” Shallow-water benthic community ecology is a flourishing and inexpensive endeavor, 

and advances in community ecology should help the conservation of tidal flats inside and outside 

critical habitats and may prevent extinction of the piping plover. 

In late February, piping plovers begin leaving the wintering grounds to migrate back to their 

breeding sites. Northward migration peaks in late March, and by late May most birds have left the 

wintering grounds. The migration of the piping plover is poorly understood. On the northern 

breeding grounds, river alteration and reservoir creation cause high water flow where birds once 

relied on exposed sand bars to breed. However, diversion of peak flows in northern nesting 

habitat is also harmful. The result is encroachment of vegetation usually kept under control by 

scour during high river flows. 

Vegetation imposes an extreme threat of predators on breeding adults. However, breeding in the 

open in temperate climates requires that parents may have to take turns brooding and soaking 

themselves in water to avoid overheating, and excess heat will cause desertion. Females may 

renest soon after but males may take longer to renest, if they do so at all (Szekely and Williams, 

1995; Szekely et al., 1999). 

Whooping Crane 

The whooping crane (Grus americana) is an omnivorous, wading bird. The whooping crane 

formerly ranged from summer breeding grounds within the central Canadian provinces and 

northern prairie states to southern coastal wintering grounds from central Mexico to the Carolinas 

(Bent, 1926). Whooping cranes currently exist in three wild populations and at five captive 

locations (USDOI, FWS, 1994). The only self-sustaining wild population nests in the Northwest 
5

Territories and adjacent areas of Alberta, Canada, primarily within the boundaries of Wood 

Buffalo National Park (WBNP). These birds winter in coastal marshes and estuarine habitats 

along the Gulf Coast at Aransas National Wildlife Refuge (ANWR), Texas, and represent the 

majority of the world’s population of free-ranging whooping cranes. Another wild flock was 

created with the transfer of wild whooping crane eggs from nests in the WBNP to be reared by 

wild sandhill cranes in an effort to establish a migratory, Rocky Mountains Population (USDOI, 

FWS, 1994). This population summers in Idaho, western Wyoming, and southwestern Montana 

and winter in the middle Rio Grande Valley, New Mexico. The third wild population is the first 

step in an effort to establish a nonmigratory population in Florida (USDOI, FWS, 1994). The 

December 1993 wild population was estimated at 160; the captive population contained 101 birds 

(USDOI, FWS, 1994). 

Bald Eagle 

The bald eagle (Haliaeetus leucocephalus) is the only species of sea eagle that regularly occurs 

on the North American continent (USDOI, FWS, 1984). Its range extends from central Alaska 

and Canada to northern Mexico. The bulk of the bald eagle’s diet is fish, though bald eagles will 

opportunistically take birds, reptiles, and mammals (USDOI, FWS, 1984). The historical nesting 

range of the bald eagle within the Southeast U.S. included the entire coastal plain and shores of 

major rivers and lakes. The current range is limited, with most breeding pairs occurring in Florida 

and Louisiana, and some in South Carolina, Alabama, and east Texas. In 1997, 120 nests were 

known in Louisiana; only 3 nests occurred within 5 mi of the coast (Patrick, written 

communication, 1997). In 2007, about 300-400 nesting pairs were located in Louisiana. The 

majority of bald eagles is migratory and is only in Louisiana from about October 15 to about May 

15 (Dunne, 2007). The bald eagle was listed as endangered in 1967 in response to the declines 

due to DDT and other organochlorines that affected the species’ reproduction (USDOI, FWS, 

1984). Recovery may be slowed by human disturbance if it affects the abundance of preferable 

trees for nesting and perching. Preferred perch trees may be relatively large in diameter, height, 

surrounding percent forest cover, surrounding size of block of forest, height of surrounding 

canopy above the ground, height of perch above surrounding canopy, and size of the angle of 

open flight path to the perch (Buehler et al., 1992; Chandler et. al., 1995). For preferred nest trees, 

important features may be proximity to water (usually within 1/2 mile), a clear flight path to a 

close point on the water, an open view of the surrounding area and proximity to preferable perch 

trees. In July 1995, the FWS reclassified the bald eagle from endangered to threatened in the 

lower 48 states (Federal Register, 1995b). The FWS expects to declassify the bird from the list 

completely in June 2007 (Dunne, 2007). 

Brown Pelican 

The brown pelican (Pelicanus occidentalis) is one of two pelican species in North America. It 

feeds entirely upon fishes captured by plunge diving in coastal waters. Organochlorine pesticide 

pollution apparently contributed to the endangerment of the brown pelican. Organochlorines like 

DDT accumulate up the food web and reach their highest concentrations in predators such as the 

brown pelican. The pesticides interfere with calcium metabolism, causing reduced calcification of 

egg shells, and potentially allowing the eggs to be crushed under the weight of an incubating 

parent. In recent years, there has been a marked increase in brown pelican populations within the 

former range of the species. The population of brown pelicans and their habitat in Alabama, 

Florida, Georgia, North and South Carolina, and points northward along the Atlantic Coast were 

removed from the endangered species list in 1985; however, within the remainder of the range, 

which includes coastal areas of Texas, Louisiana, and Mississippi, where populations are not 

secure, the brown pelican remains listed as endangered (Federal Register, 1985b). In 2004, 

16,501 nesting pairs produced an all-time high of 39,021 fledglings. Production decreased 35.2 

percent in 2005 to 25,289 fledglings as a result of an oil spill at the West Breton Island colony 
6

caused by Tropical Storm Arlene and by the cumulative effects of Hurricanes Cindy, Dennis, 

Emily, Katrina, and Rita. Ninety-five percent of production occurred west of the Mississippi 

River. Young brown pelicans there had reached flight stage at the time of Hurricane Katrina with 

no direct mortality at colonies. Conversely, brown pelicans incubating eggs and caring for 5- to 6-

week-old young east of the Mississippi River when Hurricane Katrina struck were impacted as 

eggs and young were washed away. Colonies there were repeatedly flooded by Tropical Storm 

Arlene and the hurricanes, causing fledgling mortality. In addition, Hurricane Ivan in 2004 and 

Hurricanes Katrina and Rita in 2005 caused catastrophic destruction of barrier islands and brown 

pelican nesting colonies. Hurricane Katrina reduced the size of the Chandeleur Islands by 90 

percent and completely washed away West Breton Island, Mitchell Island, and Grassy Island 

(Huntnfish.com, 2007). Other major causes of decline of the brown pelican are colony site 

erosion, disease, and human disturbance (Boggs, written communication, 2007). The Louisiana 

Department of Wildlife and Fisheries submitted a request in March 1994 to the FWS to officially 

remove the eastern brown pelican from the endangered species list in Louisiana (Louisiana Dept. 

of Wildlife and Fisheries, 1994). 

Routine Impacts on Coastal and Marine Birds 

This section discusses the possible effects of routine activities associated with a proposed action 

in the WPA and CPA on coastal and marine birds of the GOM and its contiguous waters and 

wetlands. Federally listed endangered or threatened bird species are included in this discussion 

with non-listed bird species because the potential impacts are the same or very similar. Major, 

potential impact-producing factors for marine birds in the offshore environment include OCSrelated helicopter and service-vessel traffic and noise, air emissions, degradation of water quality, 

habitat degradation, discarded trash and debris from service-vessels and OCS structures, and 

structure lighting and presence. Any effects on birds are especially grave for intensively managed 

populations. For example, endangered and threatened species may be harmed by any impact on 

viable reproductive population size or disturbance of a few key habitat factors. 

Proposed Action Analysis 

Noise 

The transportation or exchange of supplies, materials, and personnel between coastal 

infrastructure and offshore oil and gas structures is accomplished with helicopters, aircraft, and 

boats and a variety of service vessels. It is projected that 400,000-900,000 helicopter operations 

related to a proposed action in the WPA, and 1,000,000-2,200,000 helicopter operations related to 

a proposed action in the CPA, would occur over the life of a proposed action. This is a rate of 

10,000-22,500 annual helicopter operations in the WPA and 25,000-55,000 annual helicopter 

operations in the CPA. Service vessels would use selected nearshore and coastal (inland) 

navigation waterways, or corridors, and adhere to protocol set forth by the USCG for reduced 

vessel speeds within these inland areas. It is projected that 94,000-155,000 service-vessel round 

trips related to a proposed action in the WPA, and 117,000-239,000 service-vessel round trips 

related to a proposed action in the CPA would occur in the life of a proposed action; this is a rate 

of 2,350-3,875 WPA service-vessels trips annually and 2,925-5,975 CPA service vessel trips 

annually. 

Disturbances from OCS-related helicopter or service-vessel traffic to coastal birds can result from 

the mechanical noise or physical presence (or wake) of the vehicle. This discussion applies to 

both federally listed endangered/threatened bird species and non-listed species since the effects 

are the same or very similar. The degree of disturbance exhibited by groups of coastal birds to the 

presence of air or vessel traffic is highly variable, depending upon the bird species in question, 

type of vehicle, altitude or distance of the vehicle, the frequency of occurrence of the disturbance, 

and the season. Helicopter and service vessel traffic related to OCS activities could sporadically 

disturb feeding, resting, or nesting behavior. Disturbance can also lead to a permanent desertion 

of active nests and even whole nest colonies, or of critical or preferred habitat, which could 

contribute to the relocation of a species or group to less favorable areas or to a decline of species 

through reproductive failure resulting from nest abandonment. Interruption of nesting activities 
7

such as nest building (sensitive to time budgets), foraging for food for nestlings (sensitive to time 

and energy budgets), and incubation of eggs and naked nestlings (sensitive to time budgets) may 

result in reduced breeding success, measured by the ratio of birds fledged per nest to eggs hatched 

from a clutch. Impacts on whole nesting colonies of seabirds would be especially serious. When 

birds are flushed prior to or during migration, the energy cost could be great enough that they 

might not reach their destination on schedule or they may be more susceptible to diseases 

(Anderson, 1995). However, Nisbet (2000) reports that “there is no substantial evidence in the 

scientific literature that human disturbance affects reproductive success or colony site occupation 

among terns. There is no scientific evidence that up flights, or ‘flushing,’ are adverse effects, 

except in circumstances where they allow predators to gain access to eggs or chicks.” 

Waterfowl are more overtly responsive to noise than other birds and seem particularly responsive 

to aircraft, possibly because aerial predators frequently harass them (Bowles, 1995). The FAA 

and corporate helicopter policy advise helicopters to maintain a minimum altitude of 700 ft while 

in transit offshore and 500 ft while working between platforms. When flying over land, the 

specified minimum altitude is 1,000 ft over unpopulated areas or across coastlines and 2,000 ft 

over populated areas and biologically sensitive areas such as wildlife refuges and national parks. 

Many undisturbed coastal areas and refuges provide preferred and/or critical habitat for feeding, 

resting (or staging), and nesting birds. The effect of low-flying aircraft within the vicinity of 

aggregations of birds on the ground or on the water typically results in mass disturbance and 

abandonment of the immediate area. However, pilots traditionally have taken great pride in not 

disturbing birds. Compliance to the specified minimum altitude requirements greatly reduces the 

effects of aircraft disturbance on coastal and marine birds. The routine presence of aircraft at 

sufficiently high altitudes results in acclamation of birds to routine noise. As a result of inclement 

weather, about 10 percent of helicopter operations would occur at altitudes somewhat below the 

minimums listed above. Although these incidents are seconds in duration and sporadic in 

frequency, they can disrupt coastal bird behavior and, at worst, possibly result in habitat or nest 

abandonment. Birds in flight over water typically avoid helicopters. Low-flying aircraft may 

temporarily disrupt feeding or flight paths, including low-altitude foraging trips where birds scan 

the ground for small prey or scan the water for schools of small pelagic fish. The routine presence 

and low speeds of service vessels within inland and coastal waterways would diminish the effects 

of disturbance from service vessels on nearshore and inland populations of coastal and marine 

birds. Nisbet (2000) reports that 

. . . heart rates of Common Tern increased when recorded sounds associated with 

disturbance (alarm calls of terns or shorebirds, or aircraft noise) were played to them, but 

that responses declined in intensity after the stimulus was repeated about 20 times. High 

tolerance levels to various types of human disturbance have been reported frequently in 

terns and have been interpreted as resulting from habituation. In my own studies of 

Common Tern, some individuals can be touched on the nest [after habituation] and 

others stand on our head and shoulders . . . a few [Roseate Terns] now peck our heads or 

fingers. 

Terns also become tolerant to heavy boat traffic. Common Terns in New York 

ignored heavy boat traffic within a few meters of their nests . . . . Species in which 

adverse effects have been convincingly documented include pelicans [and] Doublecrested Cormorant . . . Most of the effects that have been documented 

convincingly...resulted from disturbance early in the nesting cycle, from promotion of 

predation, or both. There is little evidence of effects on productivity of gulls or herons. 

Birds can lose eggs and young when predators attack nests after parents are flushed into flight by 

service-vessel noise. Overall breeding success (ratio of fledged birds per nest to hatched birds per 

nest) may be reduced. Chronic effects on breeding are especially serious for endangered or 

threatened species because subsequent recovery may not occur. 

Air Quality Degradation 
8

Contamination of wildlife by air emissions can occur in three ways: inhalation, absorption, and 

ingestion. Inhalation is the most common mode of contamination for birds (Newman, 1980). This 

discussion applies to both federally listed endangered/threatened bird species and non-listed 

species since the effects are the same or very similar. The major effects of air pollution include 

direct mortality, debilitating injury, disease, physiological stress, anemia, hypocalcemic 

condition, bioaccumulation of air pollutants with associated decrease in resistance to debilitating 

factors, and population declines (Newman, 1979). Direct effects can be either acute, such as 

sudden mortality from hydrogen sulfide, or chronic, such as fluorosis from fluoride emissions. 

The magnitude of effect, acute or chronic, is a function of the pollutant, its ambient concentration, 

pathway of exposure, duration of exposure, and the age, sex, reproductive condition, nutritional 

status, and health of the animal at the time of exposure (Newman, 1980). Pollutants will 

accumulate in tissues with unusually low temperatures, low blood content, and low blood flow. 

Fatty tissues in any organism are especially serious sinks for nonpolar, non-ionic, hydrophobic 

pollutants. Such pollutants are probably transmitted up the food web without amplification or 

diminution in concentration. The total amounts transferred up the web probably relate to the total 

fat content of the components of the food web. Seabirds usually feed in flight and need only 

resupply moderate protein and fat stores. However, songbirds and shorebirds cannot feed over 

barriers like the open water of the GOM and need to store up large amounts of fat before flight 

over them. Such fat stores are especially sensitive to accumulation of hydrophobic contaminants. 

Top predators on trans-Gulf migrants, such as the breeding peregrine falcons on offshore 

platforms, are somewhat sensitive to accumulation of such contaminants but the toxins are no 

threat compared with the historical notorious effects of polychlorinated insecticides on egg-shell 

thinning in top bird predators such as the bald eagle and peregrine falcon. For metals in air 

emissions, chemical composition as well as size of particulate compounds has been shown to 

influence the toxicity levels in animals. Particulate size affects retention time and clearance from 

and deposition in the respiratory tract (Newman, 1981). Migratory birds may be sensitive because 

of sustained high ventilation rates required for flight. 

Levels of sulfur oxide (mainly sulfur dioxide, SO2) emissions from hydrocarbon combustion from 

OCS-related activities are of concern in relation to birds. Research specific to birds has elucidated 

both acute and chronic effects from SO2 inhalation (Fedde and Kuhlmann, 1979; Okuyama et al., 

1979). Due to their lack of tracheal submucosal glands, birds appear to have more tolerance for 

inhaled SO2 than most mammals (Llacuna et al., 1993; Okuyama et al., 1979). This suggestion 

stems from laboratory investigations where the test subject was the domestic chicken, and results 

from these studies are not necessarily applicable to wild bird species. Acute exposure of birds to 

100 ppm SO2 produced no alteration in heart rate, blood pressure, lung tidal volume, respiratory 

frequency, arterial blood gases, or blood pH. 

Exposure to 100 ppm or less of SO2 did not affect respiratory mucous secretion. Exposure to 

1,000 ppm SO2 caused mucus to increase and drip from the mouths of birds, but lungs appeared 

normal. Exposure to 5,000 ppm resulted in gross pathological changes in airways and lungs, and 

then death (Fedde and Kuhlmann, 1979). Chronic (two week) exposure of birds to three 

concentrations of SO2 for 16 hr/day for various total periods showed a statistical change in 10 

cellular characteristics and resulted in cellular changes characteristic of persistent bronchitis in 69 

percent of the tests done (Okuyama et al., 1979). 

The indirect effects of air emissions on wildlife include food web contamination and habitat 

degradation, as well as adverse synergistic effects of air emissions with natural and other 

manmade stresses. Air emissions can cause shifts in trophic structure that alter habitat structure 

and change local food supplies (Newman, 1980). The acidification of waterbodies affects the 

trophic structure by changing the abundance of phytoplankton and zooplankton. This change in 

the base of the food chain can then affect the prey species that birds rely on for feeding and 

reproduction. A similar action takes place in forests, affecting bird habitat (Environmental 

Science and Research, 1998). Acid deposition affects some inland waterbodies but typically has 

little effect on marine waters. 
9

Air pollutants may cause a change in the distribution of certain bird species (e.g., Newman, 1977; 

Llacuna et al., 1993). Migratory bird species will avoid potentially suitable habitat in areas of 

heavy air pollution in favor of cleaner areas if available (Newman, 1979). The abundance and 

distribution of passerine birds, both active and sedentary, and migratory species, as well as 

nonpasserine and nonmigratory varieties, are also greatly affected by natural factors such as 

weather and food supply. Therefore, any reduction in the number of birds within a given locale 

does not have a diagnostic certainty pointing to air emissions (Newman, 1980). 

Emissions of pollutants into the atmosphere from the activities associated with a proposed action 

would have minimum effects on offshore and onshore air quality because of the prevailing 

atmospheric conditions, emission heights and rates, and pollutant concentrations. The U.S. 

ambient air quality standards for NO2, SO2, and PM10 are 100, 80, and 50 micrograms/m3, 

respectively. Estimated increases in onshore annual average concentrations of NO2, SO2, and 

PM10 would be less than 0.42, 0.04, and 0.02 micrograms/m3, respectively, per modeled steady 

state concentrations, only a tiny fraction of the limits. These concentrations are far below 

concentrations that could harm coastal and marine birds. The most likely pathway for air 

pollution to affect birds is through acidification of inland waterbodies and soils and a subsequent 

change in trophic structure (Environmental Science and Research, 1998). 

Water Quality Degradation 

This discussion applies to both federally listed endangered/threatened bird species and non-listed 

species since the effects are the same or very similar. Expected degradation of coastal and 

estuarine water quality resulting from of OCS-related discharges may affect coastal birds directly 

by means of acute or chronic toxic effects from ingestion or contact, or indirectly through the 

contamination of food sources. Operational discharges or runoff in the offshore environment 

could also affect seabirds (e.g., laughing gulls) that remain and feed in the vicinity of offshore 

OCS structures and platforms. These impacts could also be both direct and indirect. Many 

seabirds feed and nest in the Gulf, so water quality may affect breeding success also (measured as 

the ratio of fledged birds per nest to hatched birds per nest). 

Maintenance dredging operations remove several million cubic feet of material, resulting in 

localized impacts (primarily increased turbidity and resuspended contaminants) during the 

duration of the operations. Water clarity will decrease over time within navigation channels used 

for vessel operations and within pipeline canals due to continuous sediment influx from bank 

erosion, natural widening, and reintroduction of dredged material back into surrounding waters. A 

proposed action would result in a very small incremental contribution to the need for channel 

maintenance. Coastal and marine birds that feed exclusively within these locations would likely 

experience chronic, sublethal physiological stress. Some coastal and marine birds would 

experience a decrease in viability and reproductive success that would be indistinguishable from 

natural population variations. 

Habitat Degradation 

Habitat can be described as the physical environment and as the plant substrates used by a bird. 

The northern GOM and areas inland from it have a large diversity of habitats for birds of all 

types, including migrants, wintering birds, and breeding birds. The greatest negative impact to 

coastal and marine birds is loss or degradation of preferred or critical habitat. This discussion 

applies to both federally listed endangered/threatened bird species and non-listed species since the 

effects are the same or very similar. The extent of bird displacement resulting from habitat loss is 

highly variable between different species, based upon specific habitat requirements and 

availability of similar habitat in the area. Habitat requirements for most bird species are 

incompletely known. Bird species with similar habitat may crowd each other, depending on the 

amount of available habitat controlling bird population sizes versus other types of population 

regulation. 
10

Generally, the destruction of wetland habitat from OCS pipeline landfalls and onshore 

construction may displace localized groups or populations of birds. Environmental regulations 

require replanting and restoration of wetlands destroyed by pipelaying barges and associated 

onshore pipeline installation. As these birds move to undisturbed areas of similar habitat, their 

presence may augment habitat utilization pressure on these selected areas as a result of intra- and 

interspecific competition for space or food. Pipeline landfalls and terminals, and other onshore 

OCS-related construction, can destroy coastal bird feeding or nesting habitat and can displace 

coastal bird populations from affected areas. Seabird nesting colonies are especially sensitive and 

should always be avoided by construction activities. Onshore pipelines cross a wide variety of 

coastal environments, including freshwater marsh and canals, and can therefore affect certain 

species generally not associated with marine or estuarine systems. These species include certain 

waders, marsh birds, shorebirds, and waterfowl. For a proposed action in the WPA, 0-1 new 

pipeline landfalls and 0-1 new gas processing plants are projected. For a proposed action in the 

CPA, 0-1 new pipeline landfalls and 0-1 new gas processing plants are projected. 

The analysis of the potential impacts to coastal environments concludes that a proposed action in 

the WPA or CPA is not expected to adversely alter barrier beach configurations significantly 

beyond existing, ongoing impacts in very localized areas downdrift of artificially jettied and 

maintained channels. Grand Isle is the only inhabited beach area on the Louisiana coast, but many 

unoccupied beaches occur. Initial adverse impacts and more secondary impacts of pipeline and 

navigation canals are the most significant OCS-related and proposed-action-related impacts to 

wetlands. Initial impacts are locally significant and largely limited to where OCS-related canals 

and channels pass through wetlands. Secondary impacts may have substantial, progressive, and 

cumulative adverse impacts to the hydrologic basin or subbasin in which they are found. 

Debris 

Coastal and marine birds are susceptible to entanglement in floating, submerged, and beached 

marine debris; specifically in plastics discarded from both offshore sources and land-derived litter 

and waste disposal (Heneman and the Center for Environmental Education, 1988). This 

discussion applies to both federally listed endangered/threatened bird species and non-listed 

species since the effects are the same or very similar. Studies in Florida reported that 80 percent 

of brown pelicans showed signs of injury from entanglement with fishing gear (Clapp and 

Buckley, 1984). In addition, seabirds ingest plastic particles and other marine debris more 

frequently than do any other taxon (Ryan, 1990). Interaction with plastic materials may lead to 

permanent injuries and death. Ingested debris may have three basic effects on seabirds: irritation 

and blockage of the digestive tract; impairment of foraging efficiency; and release of toxic 

chemicals, including lethal and chronically damaging substances (Ryan, 1990; Sileo et al., 

1990a). The effects of plastic ingestion may last a lifetime and may include physical deterioration 

due to malnutrition; plastics often cause a distention of the stomach, thus preventing its 

contraction and simulating a sense of satiation (Ryan, 1988). Some birds also feed plastic debris 

to their young, which could reduce survival rates and breeding success. Accumulation of plastic 

debris near foraging areas for seabird nesting colonies would be devastating to a whole cohort of 

fledging birds, especially industrial substances not intended to be associated with food 

consumption and other human activities where a health hazard would result. The chemical 

toxicity of some plastics can be high, posing a hazard in addition to obstruction and impaction of 

the gut (Fry et al., 1987). Sileo et al. (1990b) found that the prevalence of ingested plastic found 

within the gut of examined birds varied greatly among species. Species that seldom regurgitate 

indigestible stomach contents are most prone to the aforementioned adverse effects (Ryan, 1990). 

Within the GOM, these include the phalaropes, petrels, storm petrels, and shearwaters. It is 

expected that coastal and marine birds will seldom become entangled in or ingest OCS-related 

trash and debris as a result of MMS prohibitions on the disposal of equipment, containers, and 

other materials into offshore waters by lessees (30 CFR 250.40). In addition, MARPOL, Annex 

V, Public Law 100-220 (101 Statute 1458), which prohibits the disposal of any plastics, garbage, 

and other solid wastes at sea or in coastal waters, went into effect January 1, 1989, and is 

enforced by the USCG. 
11

Structures 

Every spring, migratory land birds, including neotropical passerines that cannot feed at the water 

surface or rest there, cross the GOM from wintering grounds in Latin America to breeding 

grounds north of the GOM. Some birds use offshore platforms as stopover sites for this 

migration, which may enhance fitness. This discussion applies to both federally listed 

endangered/threatened bird species and non-listed species since the effects are the same or very 

similar. 

Migrants sometimes arrive at certain platforms shortly after nightfall or later and proceed to circle 

those platforms (the phenomenon is called a nocturnal circulation event) for variable periods 

ranging from minutes to hours. Russell (2005) notes that “because of the anecdotal nature of our 

circulation observations, we are reluctant even to speculate about the average duration of 

participation in circulation or the typical energetic consequences of participating in these events.” 

The maximum observed number of birds participating in these circulations at one time at one 

platform was measured at 1,260 individuals. Nocturnal circulation events were only recorded 73 

times and on only five of the nine platforms studied in the spring of 2000. No nocturnal 

circulation was recorded for the other four platforms. In some of the recorded events, only one 

bird was observed (Russell, 2005). More than 100 circulating birds were recorded for 18 of the 73 

events. Circulations increase the risks for birds to collide with platform structures and with each 

other. Starving, exhausted, circulating birds may land on the platforms. Birds that dropped out of 

nocturnal circulations sometimes became trapped in well-lit interior areas of platforms, and these 

birds appeared sublethally stressed (Russell, 2005). However, a total of 140 birds on the nine 

platforms were recorded as dead because of starvation during the entire spring of 2000 study 

period (Russell, 2005). It is projected that 28-41 platforms are projected to be installed as a result 

of a proposed action in the WPA, and 28-39 platforms are projected to be installed as a result of a 

proposed action in the CPA. Nocturnal circulation on these platforms is expected to have minimal 

and mostly sublethal impacts on migrating bird populations. This conclusion results from the 

confirmed low mortality from starvation for all birds that landed on the platforms examined by 

Russell (2005) and also results from the suggested sublethal stress in birds that dropped out of 

circulation observed on the platforms by Russell (2005). The advantage of stopovers is expected 

to make up for any losses to bird populations from the nocturnal circulations. 

Summary and Conclusion 

The majority of effects resulting from a proposed action in the WPA or CPA on 

endangered/threatened and nonendangered/nonthreatened coastal and marine birds are expected 

to be sublethal: behavioral effects; sublethal exposure to or intake of OCS-related contaminants 

or discarded debris; temporary disturbances; and displacement of localized groups from impacted 

habitats. Chronic sublethal stress, however, is often undetectable in birds. As a result of stress, 

individuals may weaken, facilitating infection and disease; then, migratory species may not have 

the strength to reach their destination. Nocturnal circulation around platforms may create acute 

sublethal stress from energy loss and increase the risk of collisions, while stopovers on platforms 

would reduce energy loss. No significant habitat impacts are expected to occur directly from 

routine activities resulting from a proposed action. Secondary impacts from pipeline and 

navigation canals to coastal habitats will occur over the long-term and may ultimately displace 

species from traditional sites to alternative sites. 

Accidental Impacts on Coastal and Marine Birds 

This section discusses the impacts of accidental events associated with a proposed action in the 

WPA or CPA on coastal and marine birds. 

Oil Spills 

Oil spills pose the greatest potential impact to coastal and marine birds. Pneumonia is not 

uncommon in oiled birds and can occur when birds, attempting to clean their feathers through 

preening, inhale droplets of oil. Exposure to oil can cause severe and fatal kidney damage 
12

(reviewed by Frink, 1994). Ingestion of oils might reduce the function of the immune system and, 

thus, reduce resistance to infectious diseases (Leighton, 1990). Ingested oil may cause toxic 

destruction of red blood cells and varying degrees of anemia (Leighton, 1990). Stress, trauma, 

and shock enhance the effects of exposure and poisoning. The pathological conditions noted in 

autopsies may be directly caused by petroleum hydrocarbons or may be a final effect in a chain of 

events with oil as the initial cause and generalized stress as an intermediate cause (Clark, 1984). 

Low levels of oil could stress birds by interfering with food detection, feeding impulses, predator 

avoidance, territory definition, homing of migratory species, susceptibility to physiological 

disorders, disease resistance, growth rates, reproduction, and respiration. 

If physical oiling of individuals or local groups of birds occurs, some degree of both acute and 

chronic physiological stress associated with direct and secondary uptake of oil would be 

expected. Small coastal spills, pipeline spills, and spills resulting from accidents in navigation 

waterways can contact and affect many of the different groups of coastal and marine birds, most 

commonly marsh birds, waders, waterfowl, and certain shorebirds. Some deaths from these 

groups are to be expected. Raptors, such as the bald eagle and peregrine falcon, feed upon 

weakened or dead birds (and fish, in the case of the eagle) and as a result may become physically 

oiled or affected by the ingestion of the oiled prey. Pelicans are active swimmers and plunge dive 

for prey. They are therefore susceptible to both physical oiling and secondary effects via 

ingestion of oiled prey (i.e., fish). 

Plovers congregate and feed along tidally exposed banks and shorelines, following the tide out 

and foraging at the water’s edge. They have short stout bills and often chase mobile prey rather 

than probing well into the sediment with long slender bills like many birds of the sandpiper 

family. They may peck at infauna just below the sediment surface. Plovers can physically oil 

themselves while foraging on oiled shores or secondarily contaminate themselves through 

ingestion of oiled intertidal sediments and prey. Oil will reach the intertidal beach feeding areas 

before it will contact nests on the fore dunes. The least tern captures fish by means of shallow 

splash diving and surface dipping techniques. Some physical oiling could occur during these 

dives, as well as secondary toxic effects through the uptake of prey. It is possible that some death 

of endangered/threatened (as well as nonendangered and nonthreatened) species could occur, 

especially if spills occur during winter months when raptors and plovers are most common along 

the coastal Gulf or if spills contact preferred or critical habitat. Recruitment through successful 

reproduction is expected to take several years, depending upon the species and existing 

conditions. 

Some birds are merely stained as a result of their foraging behaviors (Vermeer and Vermeer, 

1975). Redwing blackbirds depend on stiff cattails to support their nests, so injury to such plants 

could result in reproductive failure. Birds can ingest oil when feeding on contaminated food items 

or drinking contaminated water. Oil contamination will affect the birds’ prey. Prey populations 

after the spill in the Arthur Kill shipping lane (January 1990, south coast of New York) had not 

returned to normal a year after the spill (Maccarone and Brzorad, 1995). 

Geese and herbivorous ducks feed on plants, at a lower trophic level than the other species of 

waterbirds and may not suffer damaging effects when oil is biomagnified, or at least not to the 

same degree (Maccarone and Brzorad, 1994). They still may encounter lower food availability, 

owing to the localized destruction of aquatic vegetation. Birds, such as ibises, that sift through 

mud and other sediments for small invertebrates may be exposed to high toxin levels in the 

invertebrates (Maccarone and Brzorad, 1994). Chapman (1981) noted that oil on the beach from 

the 1979 Ixtoc spill caused habitat shifts by the birds. Many birds had to feed in less productive 

feeding habitats. Similar observations were made for wading birds after the Arthur Kill spill 

Maccarone and Brzorad, 1995). Composition of prey populations changed after the spill. 

Lush vegetation helps to conceal sparsely placed nests and their contents from potential predators. 

Shoreline vegetation may die after prolonged exposure to water contaminated with oil. With 
13

destruction of vegetation, aerial predators may have easier access to eggs and chicks (Maccarone 

and Brzorad, 1994). Many species have inherently low reproductive potential, slowing recovery 

from impacts. However, long-term studies show that seabirds only occasionally encounter 

breeding catastrophes, such as those that result from massive avian egg predation. Low 

reproductive potential is matched by low natural mortality. 

A population that endures oil-spill impacts may have the disadvantage of a long-flying distance to 

habitat of neighboring colonies. Otherwise, neighboring colonies’ habitat could provide refuge 

for a bird population fleeing impacts and be a source of recruitment to a population recovering 

from impacts (Cairns and Elliot, 1987; Trivelpiece et al., 1986; Samuels and Ladino, 1983/1984) 

if refugees are welcome. However, this may not always be the case. Population recovery 

following destruction of a local breeding colony or a large group of wintering migrants would 

likely occur within 1-2 yearly breeding cycles. For many coastal and marine species, spills may 

delay the maturation and reproduction process in juveniles, and this could cause a decrease in 

reproductive success for at least one season (Butler et al., 1988). Disruption of pair bonds and 

altered cycles of reproductive hormones might also affect reproductive success for one breeding 

season (Leighton, 1990). 

Oil-Spill Response and Cleanup Activities 

Oil-spill cleanup methods often require heavy trafficking of beaches and wetland areas, 

application of oil dispersants and bioremediation chemicals, and the distribution and collection of 

oil containment booms and absorbent material. This activity and the presence of humans, along 

with boats, aircraft, and other technological creations, will also disturb coastal birds after a spill 

unless properly regulated. Investigations have shown that oil-dispersant mixtures pose a threat 

like that of oil to successful reproduction in birds (Albers, 1979; Albers and Gay, 1982). The 

external exposure of adult birds to oil/ dispersant emulsions may reduce chick survival more than 

exposure to oil alone would; however, successful dispersal of a spill will generally reduce the 

probability of exposure of coastal and marine birds to oil (Butler et al., 1988). It is possible that 

changes in size of an established breeding population may also be a result of disturbance in the 

form of personnel for shoreline cleanup, monitoring efforts, or the intensified research activity 

after oil spills unless these activities are properly regulated (Maccarone and Brzorad, 1994). As 

noted by Nisbet (2000), studies show that seabirds are not easily disturbed by human activities. 

Studies are indicating that rescue and cleaning of oiled birds makes no effective contribution to 

conservation, except conceivably for species with a small world population (Clark, 1978 and 

1984). A number of studies indicate that current rehabilitation techniques may not be effective in 

returning healthy birds to the wild (Anderson et al., 1996; Boersma, 1995; Sharp, 1995 and 1996). 

However, a more recent study questions this conclusion. It states that more long-term rigorous 

studies of rehabilitated and released birds of various species relative to unoiled birds are needed 

(Russell et al., 2003). Methods of rehabilitation depend on the species. Different species require 

different treatment protocols. Success depends on the nature of the spill and the sophistication of 

the treatment protocols, which are constantly being updated by experience (Russell et al., 2003). 

Preventative methods such as scaring birds from the path of an approaching oil slick or the use of 

booms to protect sensitive colonies in an emergency produce mixed results, depending on 

methods (Clark, 1984). Birds may habituate to the scare if it is always present. A new method of 

using unmanned (less expensive) scare techniques uses radar to detect the approach of birds. The 

deterrent device is set off only when birds are detected near a spill (Ronconi et al., 2004). 

Summary and Conclusion 

Oil spills from a proposed action in the WPA or CPA pose the greatest potential direct and 

indirect impacts to coastal and marine birds. Birds that are heavily oiled are usually killed. If 

physical oiling of individuals or local groups of birds occurs, some degree of both acute and 

chronic physiological stress associated with direct and secondary uptake of oil would be 

expected. Small coastal spills, pipeline spills, and spills from accidents in navigated waterways 

can contact and affect the different groups of coastal and marine birds, most commonly marsh 

birds, waders, waterfowl, and certain shorebirds. Lightly oiled birds can sustain tissue and organ 
14

damage from oil ingested during feeding and grooming or from oil that is inhaled. Stress, trauma, 

and shock enhance the effects of exposure and poisoning. Low levels of oil could stress birds by 

interfering with food detection, feeding impulses, predator avoidance, territory definition, homing 

of migratory species, susceptibility to physiological disorders, disease resistance, growth rates, 

reproduction, and respiration. Reproductive success can be affected by the toxins in oil. Indirect 

effects occur by fouling of nesting habitat, and displacement of individuals, breeding pairs, or 

populations to less favorable habitats. Competition may displace refugee seabirds from all 

habitats. 

New research, experience, and testing will help the efficacy of rehabilitation of oiled birds and 

probably improve scare methods that will keep birds away from an oil slick. Rehabilitation can be 

significant to the survival of threatened and endangered bird species. 

Dispersants used in spill cleanup activity can have toxic effects similar to oil on the reproductive 

success of coastal and marine birds. The, air, vehicle, and foot traffic that takes place during 

shoreline clean up activity can disturb nesting populations and degrade or destroy habitat if not 

properly regulated. 

Analysis of Spill Risk to Coastal Birds

The risk of contact to coastal birds from spills related to proposed action operations is dependent 

upon the likelihood that a spill occurs and the likelihood that the spilled oil reaches the shore 

areas inhabited or used by these birds. 

Risk from Offshore Spills >1,000 bbl 

The risk of contact to coastal birds from offshore spills >1,000 bbl is dependent upon (1) the 

likelihood that oil spills occurring from proposed action operations could be transported to the 

shoreline identified as coastal bird habitats and (2) oil-spill contact occurs during the period that 

specific coastal birds are present in the area. Figures 4-22 through 4-31 identify the shoreline 

areas representing identified coastal bird type habitat that were analyzed for spill risk and the 

results of MMS’s model trajectory simulation. Probabilities shown represent the likelihood that a 

spill >1,000 bbl would occur offshore as a result of a proposed action and the slick would reach 

various coastal bird habitats during the periods when the birds are known to use the area and 

within 10 days after the spill incident. The probabilities of occurrence and contact within 10 days 

for all species and habitats modeled range between <0.5 and 35 percent. 

In addition to accounting for wind and current transport and risk of spill occurrence, the 

combined probabilities incorporate the length of time each coastal bird type occupies the 

identified habitat. For example, the whooping crane occupies the identified habitat for 6 months 

out of the year. The chance of a spill occurring offshore and the slick reaching this habitat within 

10 days during those 6 months is calculated to be <0.5-1 percent. In contrast, waterfowl are found 

everywhere along the Gulf’s shoreline year round; thus, the risk of spill occurrence and contact is 

higher (23-35% from a proposed action in the CPA and 9-14% from a proposed action in the 

WPA). Given the widespread distribution of waterfowl throughout the Gulf Coast, if an oil spill 

from a proposed action were to occur and reach land, waterfowl habitat would likely be 

contacted. 

Risk from Offshore Spills <1,000 bbl 

About 400-21,000 bbl of oil is estimated to be spilled in offshore waters over a 40-year period 

from the estimated 800-1,500 spill events as a result of a proposed action in the WPA, and about 

5,500-26,500 bbl of oil is estimated to be spilled in offshore waters from the estimated 2,700-

4,500 spills as a result of a proposed action in the CPA; most (about 97%) of these spills would 

be #1 bbl. These volumes include volumes from 1-2 spill incidents in the size group >1,000 bbl 

and one spill incident in the size group ∃10,000 bbl. While <1 spill is estimated for some sizes of 

spills (Table 4-35), there is always a finite chance of any size spill occurring. Therefore, the 

possibility of at least one spill of each size is included in the upper spill volume estimates. 
15

For spills <1,000 bbl, only those >50 bbl would be expected to have a chance of persisting as a 

cohesive slick long enough for the slick to reach land. Few offshore spills 50-1,000 bbl are 

estimated to occur as a result of a proposed action, and few of these slicks are expected to occur 

proximate to State waters and to reach shore. Should a slick from such a spill make landfall, the 

volume of oil remaining in the slick is expected to be small. 

Risk from Coastal Spills 

Approximately 61-136 spills are estimated to occur within Gulf coastal waters from activities 

supporting the WPA and CPA proposed actions combined; most (about 90%) of these spills 

would be <1 bbl. The most likely locations of the estimated 6-15 coastal spills >1 bbl would be 

proximate to the major oil pipeline shore facilities. Except for two 3,000-bbl spills estimated to 

occur in Louisiana and Texas coastal waters under the high resource-estimate scenario, MMS 

estimates that coastal spills ∃1,000 bbl resulting from a proposed action have a low probability of 

occurrence. 

Based on the assumption that spill occurrence is proportional to the volume of oil handled, bird 

populations located near the coastal waters of the Galveston/Houston/Texas City area have the 

greatest risk of being contacted by coastal spills related to a proposed action in the WPA. A total 

of 80 percent of all oil estimated to be produced as a result of a proposed action in the WPA is 

projected to be brought into this area. Bird populations in eastern Louisiana, from Atchafalaya 

Bay to east of the Mississippi River, including Barataria Bay, have the greatest risk of being 

contacted by spills from operations related to a CPA proposed action. The greatest risk of contact 

would be from the assumed 3,000-bbl spills should they occur within or near the identified habitat 

areas when the birds are occupying those habitats.

SEA TURTLES 

The USFWS has responsibility for regulating sea turtles when they come ashore to nest. Nesting 

habitat of the loggerhead sea turtle (Caretta caretta) and the Kemp’s ridley sea turtle 

(Lepidochelys kempii) may be impacted by the proposed action. Although three other species of 

endangered sea turtles occur in the Gulf of Mexico, their nesting is not expected to be affected by 

the proposed action. 

Loggerhead Sea Turtle 

Loggerhead nesting along the Gulf Coast occurs primarily along the Florida Panhandle, although 

some nesting has been reported from Texas through Alabama as well (USDOC, NMFS and 

USDOI, FWS, 1991b). Loggerhead turtles have been primarily sighted in waters over the 

continental shelf, although many surface sightings of this species have also been made over the 

outer slope beyond the 1,000-m (3,281-ft) isobath. Sightings of loggerheads in waters over the 

continental slope suggest that they may be in transit through these waters to distant foraging sites 

or while seeking warmer waters during the winter. Although loggerheads are widely distributed 

during both summer and winter, their abundance in surface waters over the slope was greater 

during winter than in summer (Mullin and Hoggard, 2000). 

Species/Critical Habitat Description 

The loggerhead sea turtle was listed as a threatened species on July 28, 1978 (43 FR 32800). This 

species inhabits the continental shelves and estuarine environments along the margins of the 

Atlantic, Pacific, and Indian Oceans, and within the continental U.S., and it nests from Louisiana 

to Virginia. The major nesting areas include coastal islands of Georgia, South Carolina, and 

North Carolina, and the Atlantic and Gulf Coasts of Florida, with the bulk of the nesting 

occurring on the Atlantic Coast of Florida. Developmental habitat for small juveniles is the 

pelagic waters of the North Atlantic and the Mediterranean Sea. 

There is no critical habitat designated for the loggerhead sea turtle. 
16

Life History 

Loggerheads mate in late March through early June in the Southeastern U.S. Females emerge 

from the surf, excavate a nest cavity in the sand, and deposit a mean clutch size of 100-126 eggs. 

Individual females nest multiple times during a nesting season, with a mean of 4.1 nests/nesting 

individual (Murphy and Hopkins, 1984). Nesting migrations for an individual female loggerhead 

are usually on an interval of 2-3 years but can vary from 1 to 7 years (Dodd, 1988). Loggerhead 

sea turtles originating from the western Atlantic nesting aggregations are believed to lead a 

pelagic existence in the North Atlantic gyre for as long as 7-12 years or more, but there is some 

variation in habitat use by individuals at all life stages. Turtles in this early life history stage are 

called pelagic immatures. Stranding records indicate that when pelagic immature loggerheads 

reach a 40- to 60-cm (16- to 24-in) straight-line carapace length they begin to recruit to coastal 

inshore and nearshore waters of the continental shelf throughout the U.S. Atlantic and GOM. 

Benthic immature loggerheads, the life stage following the pelagic immature stage, have been 

found from Cape Cod, Massachusetts, to southern Texas, and occasionally strand on beaches in 

northeastern Mexico. Large benthic immature loggerheads (70-91 cm, 28-36 in) represent a larger 

proportion of the strandings and in-water captures along the south and western coasts of Florida 

as compared with the rest of the coast. Benthic immature loggerheads foraging in northeastern 

U.S. waters are known to migrate southward in the fall as water temperatures cool (Epperly et al., 

1995; Keinath, 1993; Morreale and Standora, 1999; Shoop and Kenney, 1992) and migrate 

northward in spring. Past literature gave an estimated age at maturity of 21-35 years (Frazer and 

Ehrhart, 1985; Frazer et al., 1994) and the benthic immature stage as lasting at least 10-25 years. 

However, in 2001 the NMFS Southeast Fisheries Science Center reviewed the literature and 

constructed growth curves from new data, estimating ages of maturity ranging from 20 to 38 

years and benthic immature stage lengths from 14 to 32 years. Juveniles are omnivorous and 

forage on crabs, mollusks, jellyfish, and vegetation at or near the surface (Dodd, 1988). Subadult 

and adult loggerheads are primarily coastal and typically prey on benthic invertebrates such as 

mollusks and decapod crustaceans in hard bottom habitats. 

Population Dynamics 

Loggerhead sea turtles occur throughout the temperate and tropical regions of the Atlantic, 

Pacific, and Indian Oceans and are the most abundant species of sea turtle occurring in U.S. 

waters. Loggerhead sea turtles concentrate their nesting in the north and south temperate zones 

and subtropics, but they generally do not nest in tropical areas of Central America, northern South 

America, and the Old World (Magnuson et al., 1990). 

In the western Atlantic, most loggerhead sea turtles nest in the geographic area ranging from 

North Carolina to the Florida Panhandle. There are five western Atlantic subpopulations, divided 

geographically as follows: (1) a northern nesting subpopulation, occurring from North Carolina to 

northeast Florida at about 29Ε N. latitude (approximately 7,500 nests in 1998); (2) a south Florida 

nesting subpopulation, occurring from 29Ε N. latitude on the east coast to Sarasota on the west 

coast (approximately 83,400 nests in 1998); (3) a Florida Panhandle nesting subpopulation, 

occurring at Eglin Air Force Base and the beaches near Panama City, Florida (approximately 

1,200 nests in 1998); (4) a Yucatán nesting subpopulation, occurring on the eastern Yucatán 

Peninsula, Mexico (Márquez, 1990) (approximately 1,000 nests in 1998) (TEWG, 2000); and (5) 

a Dry Tortugas nesting subpopulation, occurring in the islands of the Dry Tortugas, near Key 

West, Florida (approximately 200 nests per year) (USDOC, NMFS, 2001). Natal homing of 

females to the nesting beach provides the barrier between these subpopulations, preventing 

recolonization with turtles from other nesting beaches. 

Based on the available data, it is difficult to estimate the size of the loggerhead sea turtle 

population in the U.S. or its territorial waters. There is, however, general agreement that the 

number of nesting females provides a useful index of the species’ population size and stability at 

this life stage. Nesting data collected on index nesting beaches in the U.S. from 1989 to 1998 

represent the best dataset available to index the population size of loggerhead sea turtles. 
17

However, an important caveat for population trends analysis based on nesting beach data is that 

this may reflect trends in adult nesting females but may not reflect overall population growth 

rates. Given this caveat, between 1989 and 1998, the total number of nests laid along the U.S. 

Atlantic and Gulf Coasts ranged from 53,014 to 92,182 annually, with a mean of 73,751. On 

average, 90.7 percent of these nests were from the south Florida subpopulation, 8.5 percent were 

from the northern subpopulation, and 0.8 percent were from the Florida Panhandle nest sites. 

There is limited nesting throughout the GOM west of Florida, but it is not known to which 

subpopulation these nesting females belong. 

The number of nests in the northern subpopulation from 1989 to 1998 was 4,370-7,887, with a 

10-year mean of 6,247 nests. With each female producing an average of 4.1 nests in a nesting 

season, the average number of nesting females per year in the northern subpopulation was 1,524. 

The total nesting and nonnesting adult female population is estimated as 3,810 adult females in 

the northern subpopulation (TEWG, 1998 and 2000). The northern subpopulation, based on 

number of nests, has been classified as stable or declining (TEWG, 2000). Another consideration 

adding to the vulnerability of the northern subpopulation is that NMFS scientists estimate that the 

northern subpopulation produces 65 percent males, while the south Florida subpopulation is 

estimated to produce 80 percent females (USDOC, NMFS, 2001). 

The southeastern U.S. nesting aggregation is of great importance on a global scale and is second 

in size only to the nesting aggregation on islands in the Arabian Sea off Oman (Ross, 1979; 

Ehrhart, 1989; USDOC, NMFS and USDOI, FWS, 1991b). The global importance of the 

southeast U.S. nesting aggregation of loggerheads is especially important because the status of 

the Oman colony has not been evaluated recently, but it is located in an area of the world where it 

is highly vulnerable to disruptive events such as political upheavals, wars, catastrophic oil spills, 

and lack of strong protections (Meylan et al., 1995). 

Status and Distribution 

Ongoing threats to the western Atlantic loggerhead populations include incidental takes from 

dredging, commercial trawling, longline fisheries, and gillnet fisheries; loss or degradation of 

nesting habitat from coastal development and beach armoring; disorientation of hatchlings by 

beachfront lighting; nest predation by native and nonnative predators; degradation of foraging 

habitat; marine pollution and debris; watercraft strikes; and disease. 

Loggerhead sea turtles face numerous threats from natural causes. The five known 

subpopulations of loggerhead sea turtles in the northwest Atlantic that nest in the southeastern 

U.S. are subject to fluctuations in the number of young produced annually because of natural 

phenomena, such as hurricanes, as well as human-related activities. There is a significant overlap 

between hurricane seasons in the Caribbean Sea and northwest Atlantic Ocean (June to 

November) and the loggerhead sea turtle nesting season (March to November). Hurricanes can 

have potentially disastrous effects on the survival of eggs in sea turtle nests. In 1992, Hurricane 

Andrew affected turtle nests over a 90-mi length of coastal Florida. All of the eggs were 

destroyed by storm surges on beaches that were closest to the eye of this hurricane (Milton et al., 

1994). On Fisher Island near Miami, Florida, 69 percent of the eggs did not hatch after Hurricane 

Andrew, likely because of an inhibition of gas exchange between the eggshell and the submerged 

nest environment resulting from the storm surge. Nests from the northern subpopulation were 

destroyed by hurricanes that made landfall in North Carolina in the mid- to late 1990’s. Sand 

accretion and rainfall that result from these storms can appreciably reduce hatchling success. 

Recent, very active hurricane seasons, and particularly the 2004 and 2005 seasons that caused 

massive damage all along the Gulf Coast, have no doubt continued to greatly stress sea turtle 

populations in the area. These natural phenomena probably have significant, adverse effects on 

the size of specific year classes, particularly given the increasing frequency and intensity of 

hurricanes in the Caribbean Sea and northwest Atlantic Ocean. 

Kemps’ ridley sea turtle 
18

The nearshore waters of the GOM are believed to provide important developmental habitat for 

juvenile Kemp’s ridley and loggerhead sea turtles. Ogren (1988) suggests that the Gulf Coast, 

from Port Aransas, Texas, through Cedar Key, Florida, represents the primary habitat for subadult 

ridleys in the northern GOM. Stomach contents of Kemp's ridleys along the lower Texas coast 

consisted of a predominance of nearshore crabs and mollusks, as well as fish, shrimp, and other 

foods considered shrimp fishery discards (Shaver, 1991). Analyses of stomach contents from sea 

turtles stranded on upper Texas beaches apparently suggest similar nearshore foraging behavior 

(Plotkin, 1995). 

Species/Critical Habitat Description 

The Kemp’s ridley was listed as endangered on December 2, 1970. Internationally, the Kemp’s 

ridley is considered the most endangered sea turtle. Kemp’s ridleys nest in daytime aggregations, 

known as arribadas, primarily at Rancho Nuevo, a stretch of beach in Mexico, Tamaulipas State. 

The species occurs mainly in coastal areas of the GOM and the northwestern Atlantic Ocean. 

Occasional individuals reach European waters. Adults of this species are usually confined to the 

GOM, although adult-sized individuals sometimes are found on the Eastern Seaboard of the U.S. 

There is no designated critical habitat for the Kemp’s ridley sea turtle. 

Life History 

Remigration of females to the nesting beach varies from annually to every four years, with a 

mean of two years (TEWG, 1998). Nesting occurs from April into July and is essentially limited 

to the beaches of the western GOM, near Rancho Nuevo in southern Tamaulipas, Mexico. The 

mean clutch size for Kemp's ridleys is 100 eggs/nest, with an average of 2.5 nests/female/season. 

Juvenile/subadult Kemp's ridleys have been found along the Eastern Seaboard of the U.S. and in 

the GOM. Atlantic juveniles/subadults travel northward with vernal warming to feed in the 

productive, coastal waters of Georgia through New England, returning southward with the onset 

of winter to escape the cold (Lutcavage and Musick, 1985; Henwood and Ogren, 1987; Ogren, 

1989). In the Gulf, juvenile/subadult ridleys occupy shallow, coastal regions. Ogren (1989) 

suggested that in the northern Gulf they move offshore to deeper, warmer water during winter. 

Studies suggest that subadult Kemp's ridleys stay in shallow, warm, nearshore waters in the 

northern GOM until cooling waters force them offshore or south along the Florida coast (Renaud, 

1995). Little is known of the movements of the post-hatching, planktonic stage within the Gulf. 

Studies have shown the post-hatchling pelagic stage varies from one to four or more years, and 

the benthic immature stage lasts 7-9 years (Schmid and Witzell, 1997). The Turtle Expert 

Working Group (TEWG) (1998) estimates age at maturity to range from 7 to 15 years. 

Stomach contents of Kemp’s ridleys along the lower Texas coast consisted of a predominance of 

nearshore crabs and mollusks, as well as fish, shrimp, and other foods considered to be shrimp 

fishery discards (Shaver, 1991). Pelagic stage, neonatal Kemp's ridleys presumably feed on the 

available sargassum and associated infauna or other epipelagic species found in the GOM. 

Population Dynamics 

Kemp’s ridleys have a very restricted distribution relative to other sea turtle species. Data suggest 

that adult Kemp's ridley turtles are restricted somewhat to the GOM in shallow nearshore waters. 

Benthic immature turtles with a 20- to 60-cm (8- to 24-in) straight-line carapace length are found 

in nearshore coastal waters including estuaries of the GOM and the Atlantic, although adult-sized 

individuals sometimes are found on the Eastern Seaboard of the U.S. The post-pelagic stages are 

commonly found dwelling over crab-rich sandy or muddy bottoms. Juveniles frequent bays, 

coastal lagoons, and river mouths. 

Of the seven extant species of sea turtles in the world, the Kemp's ridley has declined to the 

lowest population level. Most of the population of adult females nest on the Rancho Nuevo 

beaches (Pritchard, 1969). When nesting aggregations at Rancho Nuevo were discovered in 1947, 
19

adult female populations were estimated to be in excess of 40,000 individuals (Hildebrand, 1963). 

By the early 1970’s, the world population estimate of mature female Kemp's ridleys had been 

reduced to 2,500-5,000 individuals. The population declined further through the mid-1980’s. 

Recent observations of increased nesting suggest that the decline in the ridley population has 

stopped and the population is now increasing. Nesting at Tamaulipas and Veracruz increased 

from a low of 702 nests in 1985 to 1,930 nests in 1995and to 6,277 nests in 2000. The population 

model used by the TEWG (1998) projected that Kemp's ridleys could reach the Recovery Plan’s 

intermediate recovery goal of 10,000 nesters by 2020 if the assumptions of age to sexual maturity 

and age-specific survivorship rates used in their model are correct. 

Status and Distribution 

The largest contributor to the decline of the ridley in the past was commercial and local 

exploitation, especially poaching of nests at the Rancho Nuevo site, as well as the GOM trawl 

fisheries. The advent of the Turtle Excluder Device (TED) regulations for trawlers and 

protections for the nesting beaches have allowed the species to begin to rebound. Many threats to 

the future of the species remain, including interactions with fishery gear, marine pollution, 

foraging habitat destruction, illegal poaching of nests, and the potential threats to nesting beaches 

from such sources as global climate change, development, and tourism pressures.

Routine Impacts on Sea Turtles 

Several routine impacts are considered in the EIS including contaminants, noise, vessel collisions, 

explosive platform removals and marine debris. All of these are offshore impacts and, with the 

exception of marine debris, are not expected to affect nesting sea turtles. 

Marine Debris 

A wide variety of trash and debris is commonly observed in the Gulf. Marine trash and debris 

comes from a variety of land-based and ocean sources (Cottingham, 1988). Some material is 

accidentally lost during drilling and production operations. From March 1, 1994, to February 28, 

1995, 40,580 debris items were collected in a 16-mi transect made along the Padre Island 

National Seashore (Miller et al., 1995). The offshore oil and gas industry was shown to contribute 

13 percent of the trash and debris found in the transect. Turtles may become entangled in drifting 

debris and ingest fragments of synthetic materials (Carr, 1987; USDOC, 1988; Heneman and the 

Center for Environmental Education, 1988). Entanglement usually involves fishing line or netting 

(Balazs, 1985). Once entangled, turtles may drown, incur impairment to forage or avoid 

predators, sustain wounds and infections from the abrasive or cutting action of attached debris, or 

exhibit altered behavior that threaten their survival (Laist, 1997). Sea turtles may become 

entangled onshore when nesting, or prevented from nesting due to marine debris on the nesting 

beach. Hatchlings can also become entangled on the beach or blocked from passage to the ocean 

by debris. Both entanglement and ingestion have caused the death or serious injury of individual 

sea turtles (Balazs, 1985). Balazs (1985) compiled dozens of records of sea turtle entanglement, 

ingestion, and impaction of the alimentary canal by ingested plastics, although tar was the most 

common item ingested. The marked tendency of leatherbacks to ingest plastic has been attributed 

to misidentification of the translucent films as jellyfish. Lutz (1990) concluded that turtles will 

actively seek out and consume plastic sheeting. Ingested debris may block the digestive tract or 

remain in the stomach for extended periods, thereby lessening the feeding drive, causing 

ulcerations and injury to the stomach lining, or perhaps even providing a source of toxic 

chemicals (Laist, 1997). Weakened animals are then more susceptible to predators and disease; 

they are also less fit to migrate, breed, or nest successfully. 

The initial life history of sea turtles involves the hatching of eggs, evacuation of nests, and 

commencement of an open ocean voyage. Some hatchlings spend their “lost years” in sargassum 

rafts; ocean currents concentrate or trap floating debris in sargassum (Carr, 1987). Witherington 

(1994) studied post-hatchling loggerheads in drift lines 8-35 nmi east of Cape Canaveral and 

Sebastian Inlet, Florida. Out of 103 turtles captured, 17 percent of the animals contained plastic or 

other synthetic fibers in their stomachs or mouths. The GOM had the second highest number of 

turtle strandings affected by debris (35.9%) (Witzell and Teas, 1994). Although the Kemp’s 
20

ridley is the second most commonly stranded turtle, they are apparently less susceptible to the 

adverse impacts of debris than the other turtle species for some unknown reason (Witzell and 

Teas, 1994). The MMS prohibits the disposal of equipment, containers, and other materials into 

offshore waters by lessees (30 CFR 250.40). In addition, MARPOL, Annex V, Public Law 100-

220 (101 Statute 1458) prohibits the disposal of any plastics at sea or in coastal waters. 

Proposed Action Analysis/Conclusion 

Sea turtles, both adults and hatchlings, can become entangled in or ingest debris produced by 

exploration and production activities resulting from a proposed action. The probability of plastic 

ingestion/entanglement is unknown. 

The MMS prohibits the disposal of equipment, containers, and other materials into offshore 

waters by lessees (30 CFR 250.40). Additionally, MARPOL Annex V. Public Law 100-220 (101 

Statute 1458) prohibits the disposal of any plastics at sea or in coastal waters. MMS recognized 

that the intentional jettison of trash and debris had been greatly reduced and addressed the 

unintentional and accidental loss of personal and industry-related items with the Marine Trash 

and Debris Awareness and Elimination Notice to Lessees. This NTL, first issued in 2003, 

requires the posting of awareness placards on structures and vessels, and requires offshore 

employees to complete annual training on marine debris awareness and proper handling 

procedures. The current version of this NTL is included in the Appendix. 

Greatly improved handling of waste and trash by industry, along with the annual awareness 

training required by the marine debris mitigations, is decreasing the plastics in the ocean and 

reducing the devastating effects on sea turtles. The routine activities of a proposed action are 

unlikely to have significant adverse effects on the size and recovery of any sea turtle species or 

population in the Gulf of Mexico. 

Accidental Impacts on Sea Turtles 

This section discusses the impacts of accidental events associated with a proposed action in the 

WPA or CPA on sea turtles. 

Blowouts

Improperly balanced well pressures that result in sudden, uncontrolled releases of fluids from a 

wellhead or wellbore are called blowouts. Blowouts can occur during any phase of development: 

exploratory drilling, development drilling, production, completion, or workover operations. In the 

event of a blowout, the eruption of gases and fluids may generate significant pressure waves and 

noise that may harass, injure, or kill sea turtles, depending on their proximity to the accident. 

Oil Spills

In recent years, increased regulation and decreased tolerance of potentially harmful 

experimentation with endangered species has limited the available data on adverse impacts from 

events such as oil spills. Much of the best available science about the physiological response of 

sea turtles (and marine mammals) to oil exposure comes from studies and observations done in 

the 1990’s and earlier. Also, decreasing oil spill occurrence due to increased safety and security 

requirements for petroleum transport limits the number of field observations of the effects of 

spilled oil on sea turtles and other marine fauna. 

The following key points concerning oil toxicity and impacts on sea turtles are made by 

Sheginaka (2003): 

 • Although surprisingly robust when faced with physical damage (shark attacks, boat 

 strikes), sea turtles are highly sensitive to chemical insults such as oil. 

 • Areas of oil and gas exploration, transportation, and processing often overlap with 

 important sea turtle habitats. 
21

 • Sea turtles are vulnerable to the effects of oil at all life stages—eggs, post-hatchlings, 

 juveniles, and adults in nearshore waters. 

 • Several aspects of sea turtle biology and behavior place them at particular risk, 

 including a lack of avoidance behavior, indiscriminate feeding in convergence zones, 

 and large predive inhalations. 

 • Oil effects on turtles include increased egg mortality and developmental defects; 

 direct mortality due to oiling in hatchlings, juveniles, and adults; and negative 

 impacts to the skin, blood, digestive and immune systems, and salt glands. 

When an oil spill occurs, the severity of effects and the extent of damage to sea turtles are 

affected by geographic location; hydrocarbon type, dosage, and weathering; impact area; 

oceanographic and meteorological conditions; season; and life history stages of animals exposed 

to the hydrocarbons (NRC, 2003). All sea turtle species and life stages are vulnerable to the 

harmful effects of oil through direct contact or by fouling of their habitats and prey. Van Vleet 

and Pauly (1987) suggested that discharges of crude oil from tankers were having a significant 

effect on sea turtles in the Eastern GOM. Experiments on the physiologic and clinicopathologic 

effects of hydrocarbons have shown that major body systems of sea turtles are adversely affected 

by short exposure to weathered oil. Sea turtles accidentally exposed to oil or tarballs may suffer 

inflammatory dermatitis, ventilatory disturbance, salt gland dysfunction or failure, red blood cell 

disturbances, immune responses, and digestive disorders or blockages (Vargo et al., 1986; Lutz 

and Lutcavage, 1989; Lutcavage et al., 1995). Although disturbances may be temporary, longterm effects remain unknown, and chronically ingested oil may accumulate in organs. Direct 

contact with oil may harm developing turtle embryos. Exposure to hydrocarbons may be fatal, 

particularly to juvenile and hatchling sea turtles. 

Oil can adhere to the body surface of marine turtles. Oil has been observed to cling to the nares, 

eyes, and upper esophagus (Overton et al., 1983; Van Vleet and Pauly, 1987; Gramentz, 1988; 

Lutcavage et al., 1995). Witham (1983) found tar sealed the mouth and nostrils of small turtles. 

Turtles may become entrapped by tar and oil slicks and rendered immobile (Witham, 1978; 

Plotkin and Amos, 1988; Gramentz, 1988). Periocular tissues and other mucous membranes 

would presumably be most sensitive to contact with hydrocarbons. Skin damage in turtles is in 

marked contrast to that observed in dolphins, where all structural and biochemical changes in the 

epidermis were minor and reversible. Changes in the skin are consistent with an acute, primary 

contact or irritant dermatitis. A break in the skin barrier could act as a portal of entry for 

pathogenic organisms, leading to infection, neoplastic conditions, and debilitation (Vargo et al., 

1986). 

Turtles surfacing in an oil spill will inhale oil vapors. Any interference with operation of the 

lungs would probably reduce a sea turtle’s capacity for sustained activity (aerobic scope) and its 

dive time, both effects decreasing the turtle’s chance of survival. 

Lutcavage et al. (1995) found that operation of the salt gland in sea turtles was disrupted with 

exposure to hydrocarbons, but the disturbance did not appear until several days after exposure. 

The salt glands did recover function when tested after two weeks of recovery. Prolonged 

interference with salt gland functioning could have serious consequences since it would interfere 

with both water balance and ion regulation. Lutcavage et al. (1995) report finding oil in the feces 

of turtles that swallowed oil in experiments. Van Vleet and Pauly (1987) reported that oil ingested 

by turtles did not pass rapidly through the digestive tract but was retained within the system for a 

period of several days, thus increasing the likelihood that toxic components of oil could be 

assimilated by other internal organs and tissues of the turtle. 

Significant changes in blood chemistry following contact with hydrocarbons have been reported 

(Lutcavage et al., 1995). Hematocrit and hemoglobin concentration decreased slightly during 

contact; these parameters are critical components of the blood’s oxygen transport system. The 
22

most striking hematologic finding was an elevation of white blood cell count, which may indicate 

a “stress” reaction related to oil exposure and/or toxicity. 

Eggs, hatchlings, and small juveniles are particularly vulnerable if contacted (Fritts and 

McGehee, 1982; Lutz and Lutcavage, 1989). Female sea turtles crawling through tar to lay eggs 

can transfer the tar to the nest; this was noted on St. Vincent NWR in 1994 (USDOI, FWS, 1997). 

Potential toxic impacts to embryos will depend on the type of oil and degree of weathering, type 

of beach substrate, and especially upon the developmental stage of the embryo. Embryonic 

development in an egg may be altered or arrested by contact with oil (Fritts and McGehee, 1982). 

Fresh oil was found to be highly toxic, especially during the last quarter of the incubation period, 

whereas aged oil produced no detectable effects. Fritts and McGehee (1982) concluded that oil 

contamination of nesting beaches would have its greatest impact on nests that were already 

constructed; nests made on fouled beaches are less likely to be affected, if at all. However, 

residual oil and tarballs may be integrated into nests by nesting females. Residues may 

agglutinate sand grains where eggs are deposited, later impeding hatchlings from successfully 

evacuating nests and ultimately leading to their death. Hatchling and small juvenile turtles are 

particularly vulnerable to contacting or ingesting hydrocarbons because the currents that 

concentrate oil spills also form the debris mats in which young turtles are sometimes found (Carr, 

1980; Collard and Ogren, 1990; Witherington, 1994). This would also be true for juvenile sea 

turtles that are sometimes found in floating mats of sargassum. Oil slicks, slicketts, or tarballs 

moving through offshore waters may foul sargassum mats that hatchling and juvenile sea turtles 

inhabit, which would conceivably result in the loss of sea turtle habitat or the “take” of sea turtles. 

The result of adult sea turtles feeding selectively in surface convergence lines could be prolonged 

contact with viscous weathered oil (Witham, 1978; Hall et al., 1983). High rates of oil contact in 

very young turtles suggest that bioaccumulation may occur over their potentially long lifespan. 

Exposure to hydrocarbons may begin as early as eggs are deposited in contaminated beach sand. 

A female coming ashore to nest might be fouled with oil or transport existing residues at the 

driftline to the nest. During nesting, she might push oil mixed with sand into the nest and 

contaminate the eggs (Chan and Liew, 1988). Assuming olfaction is critical to the process, oil 

fouling of a nesting area might disturb imprinting of hatchling turtles or confuse the turtles on 

their return migration after a 6- to 8-year absence (Geraci and St. Aubin, 1985; Chan and Liew, 

1988). 

Some captive turtles exposed to oil either reduced the amount of time spent at the surface, 

possibly avoiding the oil, or became agitated and had short submergence levels (Lutcavage et al., 

1995). Sea turtles pursue and swallow tarballs, and there is no firm evidence that free-ranging 

turtles can detect and avoid oil (Odell and MacMurray, 1986). A loggerhead turtle sighted during 

an aerial survey in the GOM surfaced repeatedly within a surface oil slick for over an hour 

(Lohoefener et al., 1989). Oil might have a more indirect effect on the behavior of marine turtles. 

The effect on reproductive success could therefore be significant. 

Contact with hydrocarbons may not cause direct or immediate death but cumulative sublethal 

effects, such as salt gland disruption or liver impairment, could impair the marine turtle’s ability 

to function effectively in the marine environment (Vargo et al., 1986; Lutz and Lutcavage, 1989). 

Although many observed physiological insults are resolved in a 21-day recovery period, the 

impact of tissue oil intake on the long-term health and survival of sea turtles remains unknown 

(Lutcavage et al., 1995). There is evidence of bioaccumulation in sea turtles exposed for longer 

periods of time. After the Gulf of Iraq war, a stranded green turtle did not appear to have 

contacted hydrocarbons, but upon necropsy, was found to have large amounts of oil in its liver 

and stomach tissues (Greenpeace, 1992). 

A study of turtles collected during the Ixtoc spill determined that the three animals found dead 

had oil hydrocarbons in all tissues examined and that there was selective elimination of portions 

of this oil, indicating that exposure to the oil was chronic. The turtles evidently did not encounter 

the oil shortly before death but had been exposed to it for some time (Hall et al., 1983). The low 
23

metabolic rate of turtles may cause a limited capacity to metabolize hydrocarbons. Prolonged 

exposure to oil may have caused the poor body condition observed in the turtles, perhaps 

disrupting feeding activity. In such weakened condition, the turtles may have succumbed to some 

toxic component in the oil or some undiscovered agent. 

The primary feeding grounds for adult Kemp’s ridley turtles in the northern and southern GOM 

are near major areas of coastal and offshore oil exploration and production (USDOC, NMFS, 

1992). The nesting beach at Rancho Nuevo, Mexico, is also vulnerable and was indeed affected 

by the Ixtoc spill. The spill reached the nesting beach after the nesting season when adults had 

returned or were returning to their feeding grounds. It is unknown how adult turtles using the Bay 

of Campeche fared. It is possible that high hatchling mortality occurred that year in the oceanic 

waters of the Gulf as a result of the floating oil. 

Spill-Response Activities

In addition to the impacts from contact with hydrocarbons, spill-response activities could 

adversely affect sea turtle habitat and cause displacement from suitable habitat to inadequate 

areas. Impacting factors might include artificial lighting from night operations, booms, machine 

and human activity, equipment on beaches and in intertidal areas, sand removal and cleaning, and 

changed beach landscape and composition. Some of the resulting impacts from cleanup could 

include interrupted or deterred nesting behavior, crushed nests, entanglement in booms, and 

increased mortality of hatchlings because of predation during the increased time required to reach 

the water (Newell, 1995; Lutcavage et al., 1997). The damage assessment and restoration 

plan/environmental assessment for the August 1993 Tampa Bay oil spill also noted that 

hatchlings that were restrained during the spill response were released on beaches other than their 

natal beaches, thus potentially losing them from the local nesting population (FDEP et al., 1997). 

Additionally, turtle hatchlings and adults may become disoriented and normal behavior disrupted 

by human presence as well as industrial activity. Individual turtles covered with oil have been 

cleaned, rehabilitated, and released (e.g., FDEP et al., 1997). The strategy for cleanup operations 

should vary, depending on the season, recognizing that disturbance to the nest may be more 

detrimental than the oil (Fritts and McGehee, 1982). As mandated by OPA 90, seagrass beds and 

live-bottom communities are expected to receive individual consideration during spill cleanup. 

Required spill contingency plans include special notices to minimize adverse effects from 

vehicular traffic during cleanup activities and to maximize protection efforts to prevent contact of 

these areas with spilled oil. Loggerhead turtle nesting areas in the Chandeleur Islands, Cape 

Breton National Seashore, and central Gulf States would also be expected to receive special 

cleanup considerations under these regulations. Little is known about the effects of dispersants on 

sea turtles and, in the absence of direct testing, impacts are difficult to predict. Dispersant 

components absorbed through the lungs or gut may affect multiple organ systems and interfere 

with digestion, excretion, respiration, and/or salt-gland function. Inhalation of dispersant can 

interfere with function through the surfactant (detergent) effect. These impacts are similar to the 

empirically demonstrated effects of oil alone (Hoff and Shigenaka, 2003). 

Proposed Action Analysis

Since sea turtle habitat in the Gulf includes inshore, coastal, and oceanic waters, as well as 

numerous beaches in the region, sea turtles could be impacted by accidental spills resulting from 

operations associated with the proposed actions in the WPA and CPA. Table 4-38 lists the 

estimates for spill magnitude and abundance for Gulf coastal waters as a result of a proposed 

action, and Table 4-35 gives similar data for Federal OCS waters. However, estimates of where 

these accidents occur relative to water depth are not presented. Qualitative inspection of spill data 

indicates that the following will likely be in each planning area: many, frequent, small spills; few, 

infrequent, moderate-sized spills; and a single, unlikely, large spill. Such spills are attributed to a 

proposed action. The assessment of spill frequency (i.e., frequent, infrequent, unlikely) is based 

relative to the 40-year life span of a proposed action. 
24

Oil spills introduced specifically into coastal waters (as opposed to spills immigrating to coastal 

waters from offshore) as a result of a proposed action are assumed to encroach upon adjacent 

coastal lands. Table 4-38 shows the estimated oil that would be introduced into coastal waters as 

a result of a proposed action. 

The OSRA modeling results indicate that a large spill (>1,000 bbl) occurring in Federal offshore 

waters stands a 10-16 percent probability of impacting Texas State waters, based on a proposed 

action for the WPA (Figure 4-13). Should a large oil spill occur as a result of a proposed action 

in the CPA, Texas State offshore waters run a 2-3 percent risk of impact (Figure 4-13). State 

offshore waters of western Louisiana stand a 23-35 percent and 1-2 percent risk of impact from 

an OCS spill occurrence resulting from a CPA proposed action and a WPA proposed action, 

respectively. There is a 6-9 percent spill risk to Louisiana coastal waters east of the mouth of the 

Mississippi River from a CPA proposed action and <0.5 percent spill risk from a WPA proposed 

action. The OSRA model projected a spill risk of <0.5-1 percent for coastal and offshore waters 

eastward of Louisiana as a result of any of proposed actions (Figure 4-13). 

In general terms, coastal waters of the planning areas are expected to be impacted by many, 

frequent, small spills (<1 bbl); few, infrequent, moderately-sized spills (>1 and <1,000 bbl); and a 

single, large (>1,000 bbl) spill. Pipelines pose the greatest risk of a large spill occurring in coastal 

waters. Matagorda County, Texas, and Plaquemines Parish, Louisiana, are the most likely landfall 

locations in the WPA and the CPA, respectively, where such a large spill might occur. 

Because oil spills introduced specifically in coastal waters of Texas and Louisiana are assumed to 

impact adjacent lands, there is likelihood that spilled oil will impact sea turtle nesting beaches in 

these states. Nesting beaches along south Texas, such as the Padre Island National Seashore, are 

susceptible to such spills, thereby potentially impacting the recovery of Kemp’s ridley, hawksbill, 

green, and loggerhead sea turtle populations in the Western Gulf. In Louisiana, loggerhead 

nesting beaches on the Chandeleur Islands are vulnerable to an oil spill originating in adjacent 

waters; however, the hurricane damage suffered by these islands in the last few years has likely 

rendered them unsuitable for nesting beaches. 

Depending on the timing of the spill’s occurrence in coastal waters, its impact and resulting 

cleanup may interrupt sea turtle migration, feeding, mating, and/ or nesting activity for extended 

periods (days, weeks, months). Spills originating in or migrating through coastal waters of Texas 

or Louisiana may impact any of the five sea turtle species inhabiting the Gulf. Kemp’s ridley is 

the most endangered sea turtle species and is strongly associated with coastal waters of Texas and 

Louisiana. Also, green, hawksbill, loggerhead, and leatherback sea turtles use coastal waters of 

the Western Gulf. Aside from the acute effects noted if sea turtles encounter an oil slick, the 

displacement of sea turtles to less suitable habitats from habitual feeding areas impacted by oil 

spills may increase vulnerability to predators, disease, or anthropogenic mortality. A high 

incidence of juvenile sea turtle foraging occurs along certain coastal regions of the Gulf Coast. 

Prime examples of known foraging areas for juvenile sea turtles in the Gulf are the Texas Laguna 

Madre, extending from the Texas-Mexico border to Mansfield Pass, Texas, for green turtles; and 

Sea Rim State Park, Texas, to Mermentau Pass, Louisiana, for Kemp’s ridleys (Renaud, 2001). 

The interruption of mating and nesting activities for extended periods may influence the recovery 

of sea turtle populations. For example, a large oil spill could inhibit the mating or nesting activity 

of the Kemp’s ridley sea turtle at Texas beaches by limiting the number of eggs being fertilized or 

the number of nests being constructed for one or more years. 

Estimates from spill data show that Federal offshore waters will be subjected to many frequent 

small spills (<1 bbl); few, infrequent, moderately-sized spills (>1 and <1,000 bbl); and/or rare 

large spills (Table 4-35) as a result of the proposed actions. Spill estimates for the WPA indicate 

57-99 bbl of oil will be introduced in offshore waters from small spills (<1 bbl). An additional 

371-1,245 bbl of oil will be spilled in quantities of a >1 to <1,000 bbl spill event. A single, large 

spill (>1,000 bbl) is estimated to introduce approximately 4,600 bbl of oil. A single, but unlikely, 
25

spill may occur that introduces as much as 15,000 bbl of oil. The total volume of oil spilled in 

Federal offshore waters as a result of the proposed actions in the WPA is estimated at 371-20,845 

bbl of oil spread over the 40-year life span of the proposed actions. 

Oil-spill data derived from historical trends estimate that a total volume of 5,666-26,575 bbl of oil 

will be introduced into Federal offshore waters over 40 years as a result of the proposed lease 

sales in the CPA. Small spills (<1 bbl) are projected to introduce 182-304 bbl of oil. Moderatesized spills (>1 and <1,000 bbl), though occurring less frequently than smaller spills, will 

introduce an estimated 884-2,071 bbl of oil. One or two large spills (>1,000 bbl) are assumed to 

introduce approximately 4,600-9,200 bbl of oil as a result of proposed actions in the CPA. In the 

rare event that a spill exceeding 10,000 bbl should occur, it is estimated that approximately 

15,000 bbl of oil will be spilled. All neonate sea turtles undertake a passive voyage via oceanic 

waters following nest evacuation. Depending on the species and population, their voyage in 

oceanic waters may last 10 or more years. Beaches of the Caribbean Sea and GOM are used as 

nesting habitat, and hatchlings evacuating these nesting beaches emigrate to oceanic waters 

seaward of their nesting sites. Surface drifter card data (Lugo-Fernandez et al., 2001) indicate that 

circulation patterns in the Caribbean Sea and southern GOM may transport neonate and young 

juvenile sea turtles from these areas to oceanic waters off the coasts of Texas and Louisiana. 

Moreover, these journeys begin as pulsed events, with many hatchlings emerging and emigrating 

offshore at the same times. Oceanic OCS waters of the GOM are also inhabited by subadult and 

adult leatherback and loggerhead sea turtles; however, adults of any endemic sea turtle species 

may be found offshore. Consequently, intermediate to large spills occurring in these waters may 

impact multiple turtles, particularly neonate or young juvenile sea turtles associating with oceanic 

fronts or refuging in sargassum mats where oil slicks, decomposing residues, and tarballs are 

likely to accumulate. Large spills, particularly those flowing fresh hydrocarbons into oceanic 

and/or outer shelf waters for extended periods (days, weeks, months), pose an increased risk of 

impacting sea turtles inhabiting these waters. It is noteworthy that such an event may impact 

entire cohorts originating from nesting beaches in the Caribbean or southern Gulf, as well as 

those originating from Texas and Louisiana nesting beaches. There is an extremely small 

probability that a single sea turtle will encounter an oil slick resulting from a single, small spill. 

Increasing the size of a slick or factoring in the number of estimated spills over 40 years increases 

the likelihood that an animal will encounter a single slick during the lifetime of an animal; many 

sea turtle species are long-lived and may traverse throughout waters of the northern Gulf. The 

web of reasoning is incomplete without considering the abundance (stock or population) of each 

species inhabiting the Gulf. The likelihood that members of a sea turtle population (e.g., Kemp’s 

ridley) may encounter an oil slick resulting from a single spill during a 40-year period is greater 

than that of a single individual encountering a slick during its lifetime. It is impossible to estimate 

precisely what sea turtle species, populations, or individuals will be impacted, to what magnitude, 

or in what numbers, since each species has unique distribution patterns in the Gulf and because of 

difficulties attributed to estimating when and where oil spills will occur over a 40-year period. 

Given the distribution of available leases and pipelines associated with the proposed actions and 

the distribution of sea turtles in the northern GOM, the fate of an oil spill must be considered 

relative to the region and period of exposure. Spill estimates derived from data documenting 

historical trends of oil spills in coastal and offshore waters indicate that the WPA and CPA 

proposed actions may introduce 11,167-31,777 bbl of oil into Gulf offshore and coastal 

environments over 40 years. Spills of any size degrade water quality, and residuals become 

available for bioaccumulation within the food chain. Slicks may spread at the sea surface or may 

migrate underwater from the seafloor through the water column and never broach the sea surface. 

Regardless, a slick is an expanding, but aggregated mass of oil that, with time, will disperse into 

smaller units as it evaporates (if at the sea surface) and weathers. As the slick breaks up into 

smaller units (e.g., slickets) and soluble components dissolve into the seawater, tarballs may 

remain within the water column. Tarballs may subsequently settle to the seafloor or attach to 

other particles or bodies in the sea. As residues of an oil spill disperse and commit to the physical 

environment (water, sediments, and particulates), sea turtles of any life history stage may be 
26

exposed via the waters that they drink and swim, as well as via the prey they consume. For 

example, tarballs may be consumed by sea turtles and by other marine organisms, and eventually 

bioaccumulate within sea turtles. Although sea turtles may (or may not) avoid oil spills or slicks, 

it is highly unlikely that they are capable of avoiding spill residuals in their environment. 

Consequently, the probability that a sea turtle is exposed to oil resulting from a spill extends well 

after the oil spill has dispersed from its initial aggregated mass. Populations of sea turtles in the 

northern Gulf will be exposed to residuals of oils spilled as a result of the proposed actions during 

their lifetimes. 

In general, on a yearly basis, about 1 percent of strandings identified by the U.S. Sea Turtle 

Stranding Network are associated with oil (e.g., Teas and Martinez, 1992). Turtles do not always 

avoid contact with oil (e.g., Lohoefener et al., 1989). Contact with petroleum and consumption of 

oil and oil-contaminated prey may seriously impact turtles; there is direct evidence that turtles 

have been seriously harmed by petroleum spills. Oil spills and residues have the potential to cause 

chronic (longer-term lethal or sublethal oil-related injuries) and acute (spill-related deaths 

occurring during a spill) effects on turtles. 

Due to spill response and cleanup efforts, much of an oil spill may be recovered before it reaches 

the coast. However, cleanup efforts in offshore waters may result in additional harm or mortality 

of sea turtles, particularly to neonates and juveniles. Oil spills and spill-response activities at 

nesting beaches, such as beach sand removal and compaction, can negatively affect sea turtles. 

Although spill-response activities such as vehicular and vessel traffic during nesting season are 

assumed to affect sea turtle habitats, further harm may be limited because of efforts designed to 

prevent spilled oil from contacting these areas. Increased human presence could influence turtle 

behavior and/or distribution, thereby stressing animals and making them more vulnerable to 

predators, the toxicological effects of oil, or other anthropogenic sources of mortality. 

In the event of a blowout, the eruption of gases and fluids may generate significant pressure 

waves and noise that may harass, injure, or kill sea turtles, depending on their proximity to the 

accident. Fortunately, improvements in technology and equipment have greatly decreased the 

occurrence of blowouts. 

Summary and Conclusion

Accidental blowouts, oil spills, and spill-response activities resulting from a proposed action in 

the WPA or CPA have the potential to impact small to large numbers of sea turtles in the GOM, 

depending on the magnitude and frequency of accidents, the ability to respond to accidents, the 

location and date of accidents, and various meteorological and hydrological factors. Populations 

of sea turtles in the northern Gulf will be exposed to residuals of oils spilled as a result of a 

proposed action during their lifetimes. Chronic or acute exposure may result in the harassment, 

harm, or mortality to sea turtles occurring in the northern Gulf. In most foreseeable cases, 

exposure to hydrocarbons persisting in the sea following the dispersal of an oil slick will result in 

sublethal impacts (e.g., decreased health, reproductive fitness, and longevity; and increased 

vulnerability to disease) to sea turtles. Sea turtle hatchling exposure to, fouling by, or 

consumption of tarballs persisting in the sea following the dispersal of an oil slick by would likely 

be fatal.

Analysis of Spill Risk to Sea Turtles

Risk from Offshore Spills >1,000 bbl 

Spills occurring as a result of a proposed action and oil slicks migrating through coastal waters 

could reach coastal sea turtle habitats. Figure 4-20 maps the locations analyzed by the OSRA 

model in calculating the risk of an oil slick contacting the general, mating, and nesting habitats of 

sea turtles. Working with FWS, MMS determined the months when sea turtles used the identified 

coastal habitats. The model results present the likelihood of slicks reaching the identified 

locations only during these months. 
27

Figure 4-20 provides the likelihood of an offshore spill ∃1,000 bbl occurring from a proposed 

action and reaching the identified coastal sea turtle habitats within 10 days during the identified 

months of use. The OSRA modeling results indicate that there is a 10-16 percent probability that 

a spill >1,000 bbl occurring as a result of a WPA proposed action and the slick reaching Texas 

waters used by sea turtles as general coastal habitat within 10 days after a spill event. There is a 

6-10 percent chance that one or more spills would occur and the slick reaching Texas waters 

within 10 days after the spill occurrence during mating season. There is a <0.5-4 percent chance 

that a spill >1,000 bbl would occur from a WPA proposed action and the slick reaching shore 

within 10 days during Texas’s sea turtle nesting season. 

The probability of an offshore oil spill >1,000 bbl occurring as a result of a proposed action in the 

CPA and the slick reaching Louisiana coastal waters used by turtles as general coastal habitat 

within 10 days ranges from 6 to 35 percent. The Chandeleur Islands is the only area in Louisiana 

considered sea turtle habitat for mating and nesting; there is up to a 4 percent chance that this 

habitat would be contacted by slick from an offshore spill >1,000 bbl occurring as a result of a 

proposed action. 

The OSRA model results show that there is a <0.5 percent chance that coastal areas in Mexico 

and Florida, when serving as sea turtle habitat, would be contacted by an oil slick resulting from 

an offshore spill >1,000 related to a proposed action. There is a <0.5 percent chance that coastal 

areas in Mississippi and Alabama, when serving as sea turtle habitat, would be contacted by an oil 

slick resulting from an offshore spill >1,000 related to a proposed action in the WPA. There is a 1 

percent chance that coastal areas in Mississippi and a <0.5-1 percent chance that coastal areas in 

Alabama, when serving as sea turtle habitat, would be contacted by an oil slick resulting from an 

offshore spill >1,000 bbl occurring as a result of a CPA proposed action. 

Tables 4-36 and 4-37 provide MMS estimates of the likely size and remaining volumes of oil 

slicks of a “typical” CPA oil and a “typical” WPA oil for several time increments after spills of 

assumed size 4,600 bbl occur. In the CPA, it is estimated that 50 bbl would remain in the slick 10 

days after the spill; about 1 km (0.6 mi) of shoreline would be contacted if the 10-day-old, 50-bbl 

slick reached shore. In the WPA, it is estimated that the slick would dissipate within 4 days. It is 

estimated that 10-50 km (6-31 mi) of land would be contacted if a slick from a WPA proposed 

action reached shore within 24 hours after the spill incident. 

Risk from All Offshore Spills 

The MMS estimates that about 400-21,000 bbl of oil would be spilled in offshore waters from an 

estimated 800-1,500 spills over the 40-year life of a proposed action in the WPA and about 5,500-

26,500 bbl of oil would be spilled in offshore waters from an estimated 2,700-4,500 spills over 

the 40-year life of a proposed action in the CPA; most (about 97%) of these spills would be <1 

bbl. These volumes include volumes from 1-2 spill incidents in the size class of >1,000 bbl and 

one in the size class of >10,000 bbl. This volume assumes one spill incident in the size group 

>1,000 bbl and one spill incident in the size group ∃10,000 bbl. While <1 spill is estimated for 

some sizes of spills (Table 4-35), there is always a finite chance of any size spill occurring. 

Therefore, the possibility of at least one spill of each size is included in the upper spill volume 

estimates. 

For spills <1,000 bbl, only those >50 bbl would be expected to have a chance of persisting as a 

cohesive slick long enough for the slick to reach land. Few offshore spills 50-1,000 bbl are 

estimated to occur as a result of a proposed action, and few of these slicks are expected to occur 

proximate to State waters and to reach shore. Should a slick from such a spill make landfall, the 

volume of oil remaining in the slick is expected to be small. 

Risk from Coastal Spills 

Approximately 61-136 spills are estimated to occur within Gulf coastal waters from activities 

supporting CPA and WPA proposed actions combined; most (about 90%) of these spills would be 
28

<1 bbl. The most likely locations of the estimated 6-15 coastal spills >1 bbl would be proximate 

to the major oil pipeline shore facilities. Except for two 3,000-bbl spills estimated to occur in 

Louisiana and Texas coastal waters under the high resource-estimate scenario, MMS estimates 

that coastal spills >1,000 bbl resulting from a proposed action have a low probably of occurrence.

Alabama, Choctawhatchee, St. Andrew, and Perdido Key Beach Mice 

Hall (1981) recognizes 16 subspecies of field mouse (Peromyscus polionotus), 8 of which are 

collectively known as beach mice. Of Gulf Coast subspecies, the Alabama, Choctawhatchee, St. 

Andrew, and Perdido Key, beach mice occupy restricted habitats in the mature coastal dunes of 

Florida and Alabama. All four mice are listed as endangered: the Alabama subspecies in 

Alabama, and the Perdido Key, St. Andrew, and Choctawhatchee subspecies in Florida (USDOI, 

FWS, 1987). Populations have fallen to levels approaching extinction. For example, in the late 

1980’s, estimates of total remaining beach mice were less than 900 for the Alabama beach mouse, 

about 80 for the Perdido Key beach mouse, and about 500 for the Choctawhatchee beach mouse. 

The Alabama, Perdido Key, and Choctawhatchee beach mice were listed as endangered in the 

1980’s. The St. Andrew beach mouse was not listed as endangered until 1998; it is the only listed 

subspecies without designated critical habitat. Continued monitoring of populations of all 

subspecies along the Gulf Coast between 1985 and the present indicates that approximately 52 

km (32.3 mi) of coastal dune habitat are now occupied by the four listed subspecies (1/3 of 

historic range). Beach mice were listed because of the loss of coastal habitat from human 

development. The reduced distribution and numbers of beach mice have continued because of 

multiple habitat threats over their entire range (coastal development and associated human 

activities, military activities, coastal erosion, and weather). The Federal Register (2006) cites 

habitat loss as the primary cause for declines in populations of beach mice. Development of 

beachfront real estate along coastal areas and catastrophic alteration by hurricanes are the primary 

contributors to loss of habitat. Destruction of Gulf Coast sand dune ecosystems for commercial 

and residential development has destroyed about 60 percent of original beach mouse habitat 

(Holliman, 1983). Recent studies indicate that this continues to be a problem (Douglass et al., 

1999; South Alabama Regional Planning Commission, 2001). 

The inland extent of beach mouse habitat may vary depending on the configuration of the sand 

dune system and the vegetation present. There are commonly several rows of dunes paralleling 

the shoreline and within these rows there are generally three types of microhabitat. The first 

microhabitat is the frontal dunes, which are sparsely vegetated with widely scattered coarse 

grasses including sea oats (Uniola paniculata), bunch grass (Andropogon maritimus), and beach 

grass (Panicum amarum and P. repens), and with seaside rosemary (Ceratiola ericoides), beach 

morning glory (Ipomoea stolonifera), and railroad vine (I. Pes-caprae). The second microhabitat 

is the frontal dune grasses, a lesser component on the higher rear scrub dunes, which support 

growth of slash pine (Pinus elliotti), sand pine (P. clausa), and scrubby shrubs and oaks, 

including yaupon (Ilex vomitoria), marsh elder (Iva sp.), scrub oak (Quercus myrtifolia), and 

sand-live oak (Q. virginiana var. maritima). The third microhabitat is the interdunal areas, which 

contain sedges (Cyperus sp.), rushes (Juncus scirpoides), and salt grass (Distichlis spicata). 

Beach mice are restricted to the coastal barrier sand dunes along the Gulf. Optimal overall beach 

mouse habitat is currently thought to be comprised of a heterogeneous mix of interconnected 

habitats including primary dunes, secondary dunes, scrub dunes, and interdunal areas. Beach mice 

dig burrows mainly in the primary, secondary, and interior scrub dunes where the vegetation 

provides suitable cover. Most beach mouse surveys conducted prior to the mid-1990’s were in 

primary and secondary dunes because the investigators assumed that these habitats are the 

preferred habitat of beach mice. A limited number of surveys in scrub dunes and other interior 

habitat resulted in less knowledge of the distribution and relative abundance there. In coastal 

environments, the terms “scrub” and “scrub dune” refer to habitat or vegetation communities 

adjacent to and landward of primary and secondary dune types where scrub oaks are visually 

dominant. Interior habitat can include vegetation types such as grass-like forbs (forbs are the 
29

herbs other than grasses). There is substantial variation in scrub oak density and cover within and 

among scrub dunes throughout ranges of beach mice. The variation, an ecological gradient, is 

represented by scrub oak woodland with a relatively closed canopy at one end of a continuum. At 

the other extreme of the gradient, scrub dunes are relatively open with patchy scrub ridges and 

intervening swales or interdunal flats dominated by herbaceous plants. 

Beach mice feed nocturnally in the dunes and remain in burrows during the day. Their diets vary 

seasonally but consist mainly of seeds, fruits, and insects (Ehrhart, 1978; Moyers, 1996). Changes 

in the availability of foods result in changes in diets between seasons and account for variability 

of seasonal diets between years. Autumn diets of beach mice consist primarily of seeds and/or 

fruits of sea oats, evening primrose (Oenothera humifusa), bluestem (Schizachyrium maritimum), 

and dune spurge (Chamaesyce ammannioides). Sea oats and beach pea (Galactia sp.) dominate 

winter diets. Spring diets primarily consist of dune toadflax (Linaria floridana), yaupon holly 

(Ilex vomitoria), seashore elder (Iva imbricata), and greenbrier (Smilax sp.). Summer diets are 

dominated by evening primrose, insects, dune toadflax, and ground cherry (Physalis augustifolia) 

(Moyers, 1996). Management practices designed to promote recovery of dune habitat, increase 

food sources, and enhance habitat heterogeneity may aid in recovery of beach mouse populations. 

In wild populations, beach mice have an average life span of about nine months. Males and 

females reach adulthood and are able to reproduce at approximately 35 days of age. Females can 

nurse one litter while pregnant with another litter. From captive colonies we know that litter size 

is 1-8 with an average of four. Young are weaned in 2-3 weeks and are generally on their own 1-2 

weeks later. 

Hurricanes are a natural environmental phenomenon affecting the Gulf Coast, and beach mice 

have evolved and persisted in coastal dune habitats since the Pleistocene. Hurricanes are part of a 

repeated cycle of destruction, alteration, and recovery of dune habitat. The extensive coastal dune 

habitat that existed along the Gulf Coast before the fairly recent commercial and residential 

development allowed beach mice to survive even the most severe hurricane events to repopulate 

dune habitat as it recovered. Beach mice are affected by the passage of hurricanes along the 

northwest Florida and Alabama Gulf Coast. Since records on hurricane intensity began in 1885, a 

total of 32 hurricanes have struck northwest Florida within the historic ranges of the four Gulf 

Coast beach mouse subspecies (Williams and Duedall, 1997; Doering et al., 1994; Neumann et 

al., 1993). In addition, 22 hurricanes have made landfall along the coast of Alabama from 1851 to 

2004 (USDOC, NOAA, National Hurricane Center, 2006). 

Hurricanes generally produce damaging winds, storm tides and surges, and rain that erode barrier 

island, peninsular, and mainland beaches and dunes. Following hurricanes, the dune system 

begins a slow natural repair process that may take 3-20 years, depending on the magnitude of 

dune loss (Salmon et al., 1982). During this period, sea oats and pioneer dune vegetation become 

established, collecting sand and building dunes. As the dunes grow and become stable, other 

successional dune vegetation colonizes the area (Gibson and Looney, 1994), and beach mouse 

food sources and habitats are reestablished. The rate of recovery of food supplies for beach mice 

is variable with some areas adversely affected for an extended period of time by hurricane and 

post-hurricane conditions. 

Tropical storms periodically devastate Gulf Coast sand dune communities, dramatically altering 

or destroying habitat, and either drowning beach mice or forcing them to concentrate on high 

scrub dunes where they are exposed to predators. How a hurricane affects beach mice depends 

primarily on its characteristics (winds, storm surge, rainfall), the time of year (midsummer is the 

worst), and where the eye crosses land (side of hurricane—clockwise or counterclockwise), 

population size, and storm impacts to habitat and food sources. The interior dunes and related 

access corridors may be essential habitats for beach mice following survival of a hurricane. For 

the three subspecies that have critical habitat areas (Alabama, Perdido Key, and Choctawhatchee 

beach mice), the major constituent elements that are known to require special management 
30

considerations or protection are dunes and interdunal areas and associated grasses and shrubs that 

provide food and cover (USDOI, FWS, 1985a and b). 

Beach mice have existed in an environment subject to recurring hurricanes, but tropical storms 

and hurricanes are now considered to be a primary factor in the beach mouse’s decline. It is only 

within the last 20-30 years that the combination of habitat loss due to beachfront development, 

isolation of remaining beach mouse habitat blocks and populations, and destruction of remaining 

habitat by hurricanes have increased the threat of extinction of several subspecies of beach mice. 

The FWS reported considerable damage to 10 National Wildlife Refuges in Alabama, 

Mississippi, Louisiana, and the Panhandle of Florida caused by Hurricane Ivan in 2004 (USDOI, 

FWS, 2004). Perdido Key, Florida, was hit hard by Hurricane Ivan, and beach mouse dune habitat 

and populations were greatly reduced. Dune habitat is recovering and tracking data have shown 

that the mice are slowly expanding back into their previous range (Haddad, 2005). Hurricane Ivan 

adversely impacted an estimated 90-95 percent of primary and secondary dune habitat throughout 

the range of the Alabama beach mouse (USDOI, FWS, 2004a). Trapping data indicate that mice 

may have been extirpated from these low-lying areas (USDOI, FWS, 2004a). The mice take 

refuge on higher ground during severe storms. Approximately 3,460 ha (1,400 ac) of higher 

elevation scrub habitat did not appear to be inundated by storm surge from either Hurricanes Ivan 

or Katrina (U.S. Army Corps of Engineers, 2001; USFWS, 2004a and b, 2005; ENSR 

Corporation, 2004) but received moderate damage from salt spray and wind (Boyd et al. 2003; 

USDOI, FWS, 2004a). The worst damage from Hurricane Ivan occurred in Alabama to Bon 

Secour National Wildlife Refuge located west of Gulf Shores, Alabama along the Fort Morgan 

Peninsula. Major primary dunes at Bon Secour were almost completely destroyed and tons of 

debris washed up on the refuge. 

Following Hurricane Opal in 1995, Swilling et al. (1998) reported higher Alabama beach mouse 

densities in the scrub than the foredunes nearly 1 year after the storm. As vegetation began to 

recover, however, the primary and secondary dunes were reoccupied by Alabama beach mice, 

and population densities surpassed those in the scrub in the fall and winter following the storm. 

Similar movement and habitat occupation patterns were observed following Hurricane Georges in 

1998. Therefore, while Alabama beach mouse numbers and habitat quality in the frontal dunes 

ebb and flow in response to tropical storms, the higher elevation scrub habitat is important to 

mouse conservation as a more stable environment during and after storm events. 

Reasons for Current Status

Beachfront development continues to be the greatest threat to beach mouse survival (Holler, 

1991; Humphrey, 1992). Habitat reduction and fragmentation have affected the ability of beach 

mice to quickly recover following tropical storms. The combinations of habitat loss to beachfront 

development, isolation of remaining habitat blocks and beach mouse populations, and destruction 

of remaining habitat by hurricanes has increased the threat of extinction for the Alabama, 

Choctawhatchee, St. Andrew, and Perdido Key beach mice within the last 20-30 years (USFWS, 

2006a).

Routine Impacts on Alabama, Choctawhatchee, St. Andrew, and Perdido Key 

Beach Mice

This section discusses the possible effects of routine activities associated with a proposed action 

in the CPA on the Alabama, Choctawhatchee, St. Andrew, and Perdido Key beach mice, which 

are designated as protected species under the Endangered Species Act of 1973 (Chapter 1.3, 

Regulatory Framework). The mice occupy restricted habitat behind coastal foredunes of Florida 

and Alabama (Ehrhart, 1978; USDOI, FWS, 1987). Portions of the beach mouse habitat have 

been designated as critical. 

Proposed Action Analysis
31

The major impact-producing factors associated with a proposed action that may affect beach mice 

include beach trash and debris, efforts undertaken for the removal of marine debris or for beach 

restoration, offshore and coastal oil spills, and spill-response activities. The potential impacts 

from spills and spill-response on beach mice activities are discussed in Chapter 4.3.5. 

Beach mice may mistakenly consume trash and debris. Mice may become entangled in the debris. 

A proposed action is expected to contribute negligible marine debris or disruption to beach mice 

areas. Efforts undertaken for the removal of marine debris, may temporarily scare away beach 

mice, destroy their food resources such as sea oats, or collapse the tops of their burrows. 

Summary and Conclusion

An impact from a proposed action in the CPA on the Alabama, Choctawhatchee, St. Andrew and 

Perdido Key beach mice is possible but unlikely. Impact may result from consumption of beach 

trash and debris. A proposed action would deposit only a small portion of the total debris that 

would reach the habitat. Efforts undertaken for the removal of marine debris, may temporarily 

scare away beach mice, destroy their food resources, or collapse the tops of their burrows.

Accidental Impacts on the Alabama, Choctawhatchee, St. Andrew, and Perdido 

Key Beach Mice 

Direct contact with spilled oil can cause skin and eye irritation and subsequent infection for 

endangered beach mice. The fur will be matted and lose its insulation against heat and cold. 

Sweat glands, ear tissues, and throat tissues may be irritated or infected. Disruption of sight and 

hearing increases vulnerability of beach mice to predators. Other direct toxic effects may include 

asphyxiation from inhalation of fumes, oil ingestion, and food contamination. Indirect impacts 

from oil spills would include reduction of food supply, destruction of habitat, and fouling of 

nests. Recovery of habitat from hurricanes involves a vital link between mouse food supply 

(involving seeds of dune-stabilizing vegetation) and habitat. The link is not unique to the beach 

mouse (it may occur in many habitats) and may be lost after an oil spill, and loss may result in 

extinction of the beach mouse after later serious storms or hurricanes or further beachfront 

development disrupt habitat. Impacts can also occur from spill-response activities. Vehicular 

traffic and other activities associated with oil-spill cleanup can degrade preferred habitat and 

cause displacement of mice from these areas without regulation. 

The ranges of the four endangered subspecies of beach mice are shown in Figure 4-21. For a 

WPA proposed action or a CPA proposed action, the probabilities were low (<0.5%) that one or 

more offshore spills ∃1,000 bbl would occur and contact the shoreline inhabited by the Alabama, 

Choctawhatchee, St. Andrews, and Perdido Key beach mice during the life of a proposed action 

(2007-2046). 

There is no definitive information on the persistence of oil, in the event that a spill were to 

contact beach mouse habitat. In Prince William Sound, Alaska, after the Exxon Valdez spill in 

1989, buried oil has been measured in the intertidal zone of beaches, but no effort has been made 

to search for residual buried oil above high tide. Similarly, NRC (2003) makes no mention of 

studies of oil left above high tide after a spill. Regardless of the potential for persistence of oil in 

beach mouse habitat, a slick cannot wash over the fore dunes unless carried by a heavy storm 

swell. Oiling of beach mice could result in extinction if it happens on a large scale (over the entire 

range of one of the subspecies), but this is very unlikely, given the chance of impact to the habitat 

is less than 0.5 percent. 

Summary and Conclusion

Given the low probability of a major (∃1,000 bbl) spill occurring, direct impacts of oil spills on 

beach mice from a proposed action are highly unlikely. Oil-spill response and clean-up activities 

could have significant impact to the beach mice and their habitat if not properly regulated.
32

Analysis of Spill Risk to Alabama, Choctawhatchee, St. Andrew, and Perdido Key 

Beach Mice

Risk from Offshore Spills >1,000 bbl 

Figure 4-21 provides the results of MMS’s analysis of the risk of a spill >1,000 bbl occurring 

offshore and reaching endangered beach mice habitat within 10 days as a result of a proposed 

action. There is a <0.5 percent chance that one or more offshore spills >1,000 bbl would occur 

and contact the shoreline inhabited by the Alabama, Choctawhatchee, St. Andrew, and Perdido 

Key beach mice during the life of a proposed action. 

Risk from Offshore Spills <1,000 bbl 

For spills <1,000 bbl, only those >50 bbl would be expected to have a chance of persisting as a 

cohesive slick long enough for the slick to reach land. Few offshore spills 50-1,000 bbl are 

estimated to occur as a result of a proposed action, and few of these slicks are expected to occur 

proximate to State waters and to reach shore. Should a slick from such a spill make landfall, the 

volume of oil remaining in the slick is expected to be small. 

Risk from Coastal Spills 

Few, if any, coastal spills are estimated to occur in Alabama or Florida coastal waters as a result 

of a proposed action, because OCS oil is not barged or pipelined to shore in Alabama or Florida, 

the states where the beach mice are found.

MITIGATIONS

The MMS is responsible for managing, regulating, and monitoring oil and natural gas 

exploration, development, and production operations on the Federal OCS to promote orderly 

development of mineral resources and to prevent harm or damage to, or waste of, any natural 

resource, any life or property, or the marine, coastal, or human environment. Regulations for oil, 

gas, and sulphur lease operations are specified in 30 CFR 250, 30 CFR 251, and 30 CFR 254. 

Measures to mitigate potential impacts are an integral part of the OCS Program. These measures 

are implemented through lease stipulations, operating regulations, NTL’s, and project-specific 

requirements or approval conditions. Mitigating measures address concerns such as endangered 

and threatened species, geologic and manmade hazards, military warning and ordnance disposal 

areas, air quality, oil-spill response planning, chemosynthetic communities, artificial reefs, 

operations in hydrogen sulfide (H2S) prone areas, and shunting of drill effluents in the vicinity of 

biologically sensitive features. 

The MMS issues NTL’s to provide clarification, description, or interpretation of a regulation; 

guidelines on the implementation of a special lease stipulation or regional requirement; or convey 

administrative information. Conditions of approval are mechanisms to control or mitigate 

potential safety or environmental problems associated with proposed operations. Conditions of 

approval are based on MMS technical and environmental evaluations of the proposed operations. 

Comments from Federal and State agencies (as applicable) are also considered in establishing 

conditions. Conditions may be applied to any OCS plan, permit, right-of-use of easement, or 

pipeline right-of-way grant. 

Some MMS-identified mitigation measures are implemented through cooperative agreements or 

efforts with the oil and gas industry and Federal and State agencies. These measures include the 

NOAA Fisheries Service Observer Program to protect marine mammals and sea turtles when 

OCS structures are removed using explosives, labeling of operational supplies to track sources of 

accidental debris loss, development of methods of pipeline landfall to eliminate impacts to barrier 

beaches, and semiannual beach cleanup events. 
33

Exploration Plans 

An EP must be submitted to MMS for review and decision before any exploration activities, 

except for preliminary activities, can begin on a lease. The EP describes exploration activities, 

drilling rig or vessel, proposed drilling and well-testing operations, environmental monitoring 

plans, and other relevant information, and includes a proposed schedule of the exploration 

activities. Guidelines and environmental information requirements for lessees and operators 

submitting an EP are addressed in 30 CFR 250.211 and further explained in NTL’s 2006-G14 and 

2006-G15. The NTL 2006-G14 provides guidance on information requirements and establishes 

the contents for OCS plans required by 30 CFR 250 Subpart B. This NTL, along with NTL 2006-

G15, supersedes NTL 2003-G17. In the revised final Subpart B regulations, the contents of an EP 

are given. The NTL 2006-G15 provides guidance for submitting OCS plans to the MMS GOMR. 

After receiving an EP, MMS performs technical and environmental reviews. The MMS evaluates 

the proposed exploration activities for potential impacts relative to geohazards and manmade 

hazards (including existing pipelines), archaeological resources, endangered species, sensitive 

biological features, water and air quality, oil-spill response, State CZMA requirements, and other 

uses (e.g., military operations) of the OCS. The EP is reviewed for compliance with all applicable 

laws and regulations. 

A CER or EA is prepared in support of the NEPA environmental review of the EP. The CER or 

EA is based on available information, which may include the geophysical report (for determining 

the potential for the presence of deepwater benthic communities); archaeological report; air 

emissions data; live-bottom survey and report; biological monitoring plan; and recommendations 

by the affected State(s), DOD, FWS (for selected plans under provisions of a DOI agreement), 

NOAA Fisheries Service, and/or internal MMS offices. As part of the review process, most EP’s 

and supporting environmental information are sent to the affected State(s) for consistency 

certification review and concurrence under the States’ approved Coastal Management Plans 

(CMP’s). After EP approval and prior to conducting drilling operations, the operator is required 

to submit and obtain approval for an Application for Permit to Drill (APD). 

Deepwater Operations Plans 

In 1992, MMS formed an internal Deepwater Task Force to address technical issues and 

regulatory concerns relating to deepwater (greater than 1,000 ft or 305 m) operations and projects 

utilizing subsea technology. Based on the Deepwater Task Force’s recommendation, an NTL 

(2000-N06) was developed, which required operators to submit a Deepwater Operations Plan 

(DWOP) for all operations in deep water (400 m (1,312 ft) or greater) and all projects using 

subsea technology. DeepStar, an industry-wide cooperative workgroup focused on deepwater 

regulatory issues and critical technology development issues, worked closely with the MMS 

Deepwater Task Force to develop the initial guidelines for the DWOP. The DWOP was 

established to address regulatory issues and concerns that were not addressed in the existing 

MMS regulatory framework, and it is intended to initiate an early dialogue between MMS and 

industry before major capital expenditures on deepwater and subsea projects are committed. 

Deepwater technology has been evolving faster than MMS’s ability to revise OCS regulations; 

the DWOP was established through the NTL process, which provides for a more timely and 

flexible approach to keep pace with the expanding deepwater operations and subsea technology. 

On August 30, 2005, the DWOP requirements were incorporated into MMS operating regulations 

via revisions to 30 CFR 250 Subpart B. 

The DWOP is intended to address the different functional requirements of production equipment 

in deep water, particularly the technological requirements associated with subsea production 

systems, and the complexity of deepwater production facilities. The DWOP provides MMS with 

information specific to deepwater equipment issues to demonstrate that a deepwater project is 

being developed in an acceptable manner as mandated in the OCSLA, as amended, and the MMS 

operating regulations at 30 CFR 250. The MMS reviews deepwater development activities from a 

total system perspective, emphasizing operational safety, environmental protection, and 
34

conservation of natural resources. The DWOP process is a phased approach that parallels the 

operator’s state of knowledge about how a field will be developed. A DWOP outlines the design, 

fabrication, and installation of the proposed development/production system and its components. 

A DWOP will include structural aspects of the facility (fixed, floating, subsea); stationkeeping 

(includes mooring system); wellbore, completion, and riser systems; safety systems; offtake; and 

hazards and operability of the production system. The DWOP provides MMS with the 

information to determine that the operator has designed and built sufficient safeguards into the 

production system to prevent the occurrence of significant safety or environmental incidents. The 

DWOP, in conjunction with other permit applications, provides MMS the opportunity to assure 

that the production system is suitable for the conditions in which it will operate. 

The MMS recently completed a review of several industry-developed, recommended practices 

that address the mooring and risers for floating production facilities. The recommended practices 

address such things as riser design, mooring system design (stationkeeping), and hazard analysis. 

The MMS is in the process of incorporating these recommended practices into the existing 

regulations. Hazard analyses allow MMS to be assured that the operator has anticipated 

emergencies and is prepared to address such, either through their design or through the operation 

of the equipment in question.

Development Operations and Coordination Documents 

Before any development operations can begin on a lease in the proposed lease sale area, a DOCD 

must be submitted to MMS for review and decision. A DOCD describes the proposed 

development activities, drilling activities, platforms or other facilities, proposed production 

operations, environmental monitoring plans, and other relevant information, and it includes a 

proposed schedule of development and production activities. Requirements for lessees and 

operators submitting a DOCD are addressed in 30 CFR 250.241-250.242, and information 

guidelines for DOCD’s are given in NTL’s 2006-G14 and 2006-G15. 

After receiving a DOCD, MMS performs technical and environmental reviews. The MMS 

evaluates the proposed activity for potential impacts relative to geohazards and manmade hazards 

(including existing pipelines), archaeological resources, endangered species, sensitive biological 

features, water and air quality, oil-spill response, State CZMA requirements, and other uses (e.g., 

military operations) of the OCS. The DOCD is reviewed for compliance with all applicable laws 

and regulations. 

A CER, EA, and/or EIS are prepared in support of the NEPA environmental review of a DOCD. 

The CER, EA, and/or EIS is based on available information, which may include the geophysical 

report (for determining the potential for the presence of deepwater benthic communities); 

archaeological report; air emissions data; live-bottom survey and report; biological monitoring 

plan; and recommendations by the affected State(s), DOD, FWS (for selected plans under 

provisions of a DOI agreement), NOAA Fisheries Service, and/or internal MMS offices. 

As part of the review process, the DOCD and supporting environmental information may be sent 

to the affected State(s) for consistency certification review and determination under the States’ 

federally approved coastal program. The OCSLA (43 U.S.C. 1345(a) through (d) and 43 U.S.C. 

1351(a)(3)) provides for this coordination and consultation with the affected State and local 

governments concerning a DOCD.

Marine Plastic Pollution Research and Control Act 

The Marine Plastic Pollution Research and Control Act of 1987 (MPPRCA) (33 U.S.C. 1901 et 

seq.) implements Annex V of the International Convention for the Prevention of Pollution from 

Ships (MARPOL). Under provisions of the law, all ships and watercraft, including all commercial 

and recreational fishing vessels, are prohibited from dumping plastics at sea. The law also 

severely restricts the legality of dumping other vessel-generated garbage and solid-waste items 

both at sea and in U.S. navigable waters. The USCG is responsible for enforcing the provisions of 
35

this law and has developed final rules for its implementation (33 CFR 151, 155, and 158), calling 

for adequate trash reception facilities at all ports, docks, marinas, and boat-launching facilities. 

The GOM has received “Special Area” status under MARPOL, thereby prohibiting the disposal 

of all solid waste into the marine environment. Fixed and floating platforms, drilling rigs, manned 

production platforms, and support vessels operating under a Federal oil and gas lease are required 

to develop waste management plans and to post placards reflecting discharge limitations and 

restrictions. 

Waste Management Plans require oil and gas operators to describe procedures for collecting, 

processing, storing, and discharging garbage and to designate the person who is in charge of 

carrying out the plan. The MMS regulations explicitly prohibit the disposal of equipment, cables, 

chains, containers, or other materials into offshore waters. Portable equipment, spools or reels, 

drums, pallets, and other loose items must be marked in a durable manner with the owner’s name 

prior to use or transport over offshore waters. Smaller objects must be stored in a marked 

container when not in use. These rules also apply to all oceangoing ships of 12 m (39 feet (ft)) or 

more in length that are documented under the laws of the U.S. or numbered by a State and that 

are equipped with a galley and berthing. Placards noting discharge limitations and restrictions, as 

well as penalties for noncompliance, apply to all boats and ships 8 m (26 ft) or more in length. 

Furthermore, the Shore Protection Act of 1988 (33 U.S.C. 2601 et seq.) requires ships 

transporting garbage and refuse to assure that the garbage and refuse is properly contained onboard so that it will not be lost in the water from inclement wind or weather conditions.

Marine Debris Research, Prevention, and Reduction Act 

The Marine Debris Research, Prevention, and Reduction Act (P.L l09-449) was enacted in 

December 2006. The purposes of this Act are (1) to help identify, determine sources of, assess, 

reduce, and prevent marine debris and its adverse impacts on the marine environment and 

navigation safety; (2) to reactivate the Interagency Marine Debris Coordinating Committee; and 

(3) to develop a Federal marine debris information clearinghouse. The Act established, within the 

National Oceanic and Atmospheric Administration, a Marine Debris Prevention and Removal 

Program to reduce and prevent the occurrence and adverse impacts of marine debris on the 

marine environment and navigation safety. 

Under the program, the Administrator shall (1) in consultation with relevant Federal agencies, 

undertake marine debris mapping, identification, impact assessment, prevention, and removal 

efforts, with a focus on marine debris posing a threat to living marine resources and navigation 

safety; (2) improve efforts to reduce adverse impacts of lost and discarded fishing gear on living 

marine resources and navigation safety; (3) undertake outreach and education of the public and 

other stakeholders, such as the fishing industry, fishing gear manufacturers, and other marinedependent industries, and the plastic and waste management industries, on sources of marine 

debris, threats associated with marine debris and approaches to identify, determine sources of, 

assess, reduce, and prevent marine debris and its adverse impacts on the marine environment and 

navigational safety, including outreach and education activities through public-private initiatives; 

and (4) acting through the Program, enter into cooperative agreements and contracts and provide 

financial assistance in the form of grants for projects to accomplish the purpose set forth in the 

Act. 

As stated in Section 8, nothing in this Act supersedes, or limits the authority of the Secretary of 

the Interior under, the Outer Continental Shelf Lands Act (43 U.S.C. 1331 et seq.).

Marine Debris Elimination and Awareness Notice To Lessees

The Marine Debris Elimination and Awareness NTL requires operators to place placards in 

prominent places on vessels and structures and to encourage awareness and minimize the 
36

unintentional and accidental release of debris. Offshore workers are required to attend annual 

marine debris awareness training. The text of the NTL is available on the MMS website at 

www.mms.gov. 

Protected Species Lease Stipulation 

A protected species stipulation has been applied to all blocks leased in the GOM since 2001. This 

stipulation would be a part of any lease resulting from the proposed actions, i.e., Sales 205, 206, 

208, 213, 216, and 222. The stipulation reads as follows: 

Protected Species Stipulation 

To reduce the potential taking of federally protected species (e.g., sea turtles, marine mammals, 

Gulf sturgeon, and other listed species): 

(a) The MMS will condition all permits issued to lessees and their operators to 

require them to collect and remove flotsam resulting from activities related to 

exploration, development, and production of this lease. 

(b) The MMS will condition all permits issued to lessees and their operators 

to require them to post signs in prominent places on all vessels and platforms 

used as a result of activities related to exploration, development, and production 

of this lease detailing the reasons (legal and ecological) why release of debris 

must be eliminated. 

(c) The MMS will require that vessel operators and crews watch for marine 

mammals and sea turtles, reduce vessel speed to 10 knots or less when 

assemblages of cetaceans are observed and maintain a distance of 90 m or greater 

from whales, and a distance of 45 m or greater from small cetaceans and sea 

turtles. 

(d) The MMS will require that all seismic surveys employ mandatory 

mitigation measures including the use of a 500-meter “exclusion zone” based 

upon the appropriate water depth, ramp-up and shut-down procedures, visual 

monitoring and reporting. Seismic operations must immediately cease when 

certain marine mammals are detected within the 500-meter exclusion zone. 

Ramp-up procedures and seismic surveys may be initiated only during daylight 

unless alternate monitoring methods approved by MMS are used. 

(e) The MMS will require lessees and operators to instruct offshore personnel 

to immediately report all sightings and locations of injured or dead protected 

species (marine mammals and sea turtles) to the appropriate stranding network. If 

oil and gas industry activity is responsible for the injured or dead animals (e.g. 

because of a vessel strike), the responsible parties should remain available to 

assist the stranding network. If the injury or death was caused by a collision with 

your vessel, you must notify MMS within 24 hours of the strike. 

(f) The MMS will require oil spill contingency planning to identify important 

habitats, including designated critical habitat, used by listed species (e.g. sea 

turtle nesting beaches, piping plover critical habitat), and require the strategic 

placement of spill cleanup equipment to be used only by personnel trained in 

less-intrusive cleanup techniques on beach and bay shores. 

Lessees and operators will be instructed how to implement these mitigation measures in NTL’s. 

This stipulation was developed in consultation with NOAA Fisheries Service and FWS, and is 

designed to minimize or avoid potential adverse impacts to federally protected species. 

Oil Spill Mitigation Measures 

Oil spills are accidental, unplanned events incidental to an otherwise legal activity (oil 

production). Large oil spills associated with OCS activities are low-probability events. However, 

should one occur, it has the highest potential of industry-related impacts to adversely affect 

coastal birds, and nesting and hatchling sea turtles. Public input through scoping meetings and 
37

Federal and State agencies’ input through consultation and coordination indicate that oil spills 

continue to be a major issue. The MMS and other responsible agencies have incorporated 

numerous regulations and mitigations to minimize the potential for adverse impact to the 

environment and the species. 

Spill Prevention 

Beginning in the 1980's, MMS established comprehensive pollution prevention requirements that 

include redundant safety systems, as well as inspection and testing requirements to confirm that 

these devices are working properly. An overall reduction in spill volume has occurred over the 

past 40 years while oil production has generally increased. The MMS attributes this improvement 

to MMS operational requirements, ongoing efforts by the oil and gas industry to enhance safety 

and pollution prevention, and the evolution and improvement of offshore technology. 

Part of those safety systems are subsurface safety valves (SSSV) and downhole safety valves 

(DSV). Should a platform be damaged, these valves “shut-in” production flow to prevent 

pollution events until the production can be safely reestablished. During Hurricanes Ivan, Katrina 

and Rita, these valves performed successfully (U.S. Senate, Committee on Energy and Natural 

Resources, 2005; USDOI, MMS, 2005). 

Likelihood of an Offshore Spill <1,000 bbl Occurring and Contacting Modeled 

Locations of Environmental Resources

Because spills <1,000 bbl are not expected to persist as a slick on the surface of the water beyond 

a few days and because spills on the OCS would occur at least 3-10 nmi from shore, it is unlikely 

that any spills would make landfall prior to breaking up. For an offshore spill <1,000 bbl to make 

landfall, the spill would have to occur proximate to State waters (defined as 3-12 mi from shore). 

If a spill were to occur proximate to State waters, only a spill >50 bbl would be expected to have 

a chance of persisting long enough to reach land. Spills >50 and <1,000 bbl size are very 

infrequent. Should such a spill occur, the volume that would make landfall would be expected to 

be extremely small (a few barrels). These assumptions are supported by a previous analysis of 3-

day trajectory model runs, previous weathering analyses, and historical records of spill incidents.

Likelihood of Coastal Spill Contact with Various Resources

The coastal spill rate is based on historical spills and the projected amount of oil production. For 

the purpose of this analysis, coastal spills are assumed to occur where oil production is brought to 

shore. Because the majority of oil production from a WPA proposed action is projected to be 

brought to shore in the Galveston/Houston/Texas City Area, it is assumed the majority of coastal 

spills from a WPA proposed action will also occur in this area. It is projected that the majority of 

oil production for a CPA proposed action will be brought to shore in eastern Louisiana, from 

Atchafalaya Bay to east of the Mississippi River. Based on this assumption the majority of coastal 

spills are projected to occur in this area, including one spill >1,000 bbl (assumed size 3,000 bbl) 

estimated to occur as the result of a CPA proposed action.

Analysis of Spill Risk to Sensitive Coastal Environments

Sensitive coastal environments located in the GOM consist primarily of coastal barrier beaches, 

wetlands, and seagrass communities. 

Risk from Offshore Spills >1,000 bbl 

Because of the widespread distribution of sensitive coastal environments along the Gulf Coast, 

specific resource locations were not analyzed by the OSRA model trajectory simulations. The 

probabilities of an offshore spill >1,000 bbl occurring and contacting coastal counties and 

parishes was used as an indicator of the risk of a slick from such a spill reaching sensitive coastal 

environments. Figures 4-13 and 4-14 show the GOM coastal counties and parishes having a risk 

>0.5 percent of being contacted within 10 days by an offshore spill >1,000 bbl occurring as a 

result of a proposed action. Most counties and parishes have a <0.5 percent probability of a spill 

>1,000 bbl occurring and contacting (combined probability) their shorelines within 10 days; six 

counties in Texas and eight parishes in Louisiana have a 1-15 percent chance of an OCS offshore 
38

spill >1,000 bbl occurring and reaching their shoreline within 10 days. In Louisiana, Plaquemines 

Parish has the greatest risk (10-15%) of a spill occurring and contacting its shoreline within 10 

days as a result of a CPA proposed action. In Texas, Matagorda County has the greatest risk (3-

5%) of being contacted within 10 days by a spill occurring offshore as a result of a WPA 

proposed action. 

Risk from Offshore Spills <1,000 bbl 

For spills <1,000 bbl, only those >50 bbl would be expected to have a chance of persisting as a 

cohesive slick long enough for the slick to reach land. Few offshore spills 50-1,000 bbl are 

estimated to occur as a result of a proposed action, and few of these slicks are expected to occur 

proximate to State waters and to reach shore. Should a slick from such a spill make landfall, the 

volume of oil remaining in the slick is expected to be small. 

Risk from Coastal Spills 

Approximately 61-136 spills are estimated to occur within Gulf coastal waters from activities 

supporting the WPA and CPA proposed actions combined. Most (about 90%) of these spills 

would be #1 bbl. The most likely locations of the estimated 6-15 coastal spills >1 bbl would be 

proximate to the major oil pipeline shore facilities. Except for two 3,000-bbl spills estimated to 

occur in Louisiana and Texas coastal waters under the high resource-estimate scenario, MMS 

estimates that coastal spills >1,000 bbl resulting from a proposed action will have a low 

probability of occurrence. 

Based on the assumption that spill occurrence is proportional to the volume of oil handled, 

sensitive coastal environments located near the coastal waters of the Galveston/Houston/Texas 

City area have the greatest risk of being contacted by coastal spills related to a proposed action in 

the WPA. A total of 80 percent of all oil estimated to be produced as a result of a proposed action 

in the WPA is projected to be to be brought into this area. Sensitive coastal environments in 

eastern Louisiana, from Atchafalaya Bay to east of the Mississippi River, including Barataria 

Bay, have the greatest risk of being contacted by spills from operations related to a CPA proposed 

action. The greatest risk of contact would be from the assumed 3,000-bbl spill should it occur 

within or near wetlands. 

Pipelines 

Regulatory processes and jurisdictional authority concerning pipelines on the OCS and in coastal 

areas are shared by several Federal agencies, including DOI, DOT, COE, the Federal Energy 

Regulatory Commission (FERC), and the USCG. Aside from pipeline regulations, these agencies 

have the responsibility of overseeing and regulating the following areas: the placement of 

structures on the OCS and pipelines in areas that affect navigation; the certification of proposed 

projects involving the transportation or sale of interstate natural gas, including OCS gas; and the 

right of eminent domain exercised by pipeline companies onshore. In addition, DOT is 

responsible for promulgating and enforcing safety regulations for the transportation in or 

affecting interstate commerce of natural gas, liquefied natural gas (LNG), and hazardous liquids 

by pipeline. This includes, for the most part, offshore pipelines on State lands beneath navigable 

waters and on the OCS that are operated by transmission companies. The regulations are 

contained in 49 CFR 191 through 193 and 195. In a MOU between DOT and DOI dated 

December 10, 1996, each party’s respective regulatory responsibilities are outlined. The DOT is 

responsible for establishing and enforcing design, construction, operation, and maintenance 

regulations, and for investigating accidents for all OCS transportation pipelines beginning 

downstream of the point at which operating responsibility transfers from a producing operator to 

a transporting operator. The DOI’s responsibility extends upstream from the transfer point 

described above. 

The MMS is responsible for regulatory oversight of the design, installation, and maintenance of 

OCS producer-operated oil and gas pipelines. The MMS operating regulations for pipelines found 

at 30 CFR 250 Subpart J are intended to provide safe and pollution-free transportation of fluids in 
39

a manner that does not unduly interfere with other users of the OCS. Pipeline applications are 

usually submitted and reviewed separately from DOCD’s. Pipeline applications may be for onlease pipelines or right-of-way for pipelines that cross other lessees’ leases or unleased areas of 

the OCS. Pipeline permit applications to MMS include the pipeline location drawing, profile 

drawing, safety schematic drawing, pipe design data, a shallow hazard survey report, and an 

archaeological report, if applicable. 

The DOI has regulatory responsibility for all producer-operated pipelines. The DOI’s 

responsibility extends downstream from the first production well to the last valve and associated 

safety equipment on the last OCS-related production system along the pipeline. The DOT’s 

regulatory responsibility extends shoreward from the last valve on the last OCS-related 

production facility. 

The MMS evaluates the design, fabrication, installation, and maintenance of all OCS pipelines. 

Proposed pipeline routes are evaluated for potential seafloor or subsea geologic hazards and other 

natural or manmade seafloor or subsurface features or conditions (including other pipelines) that 

could have an adverse impact on the pipeline or that could be adversely impacted by the proposed 

operations. Routes are also evaluated for potential impacts on archaeological resources and 

biological communities. A NEPA review is conducted in accordance with applicable policies and 

guidelines. The MMS prepares an EA on all pipeline rights-of-way that go ashore. For Federal 

consistency, applicants must comply with the requirements of NTL 2002-G15. All Gulf States 

require consistency review of ROW pipeline applications as described in the subject NTL. 

The design of the proposed pipeline is evaluated for an appropriate cathodic protection system to 

protect the pipeline from leaks resulting from the effects of external corrosion of the pipe; an 

external pipeline coating system to prolong the service life of the pipeline; measures to protect the 

inside of the pipeline from the detrimental effects, if any, of the fluids being transported; the 

submersibility of the line (i.e., that the pipeline will remain in place on the seafloor and not have 

the potential to float, even if empty or filled with gas rather than liquids); proposed operating 

pressure of the line, and protection of other pipelines crossing the proposed route. Such an 

evaluation includes (1) reviewing the calculations used by the applicant in order to determine 

whether the applicant properly considered such elements as the grade of pipe to be used, the wall 

thickness of the pipe, derating factors related to the submerged and riser portions of the pipeline, 

the pressure rating of any valves or flanges to be installed in the pipeline, the pressure rating of 

any other pipeline(s) into which the proposed line might be tied, the required pressure to which 

the line must be tested before it is placed in service; (2) protective safety devices such as pressure 

sensors and remotely operated valves, the physical arrangement of those devices proposed to be 

installed by the applicant for the purposes of protecting the pipeline from possible overpressure 

conditions and for detecting and initiating a response to abnormally low-pressure conditions; and 

(3) the applicant’s planned compliance with regulations requiring that pipelines installed in water 

depths less than 200 ft (61 m) be buried to a depth of at least 3 ft (1 m) (30 CFR 250.1003). In 

addition, pipelines crossing fairways require a COE permit and must be buried to a depth of at 

least 10 ft (3 m) and to 16 ft (5 m) if crossing an anchorage area. 

Operators are required to periodically inspect pipeline routes. Monthly overflights are conducted 

to inspect pipeline routes for leakage. 

Applications for pipeline decommissioning must also be submitted for MMS review and 

approval. Decommissioning applications are evaluated to ensure they will render the pipeline 

inert and/or to minimize the potential for the pipeline becoming a source of pollution by flushing 

and plugging the ends; and to minimize the likelihood that the decommissioned line will become 

an obstruction to other users of the OCS by filling it with water and burying the ends. 

Natural Seepage
40

Natural seeps provide the largest petroleum input to the offshore GOM, about 95 percent of the 

total. Estimates have ranged from 28,000 bbl per year to 204,000 bbl of oil per year (McDonald, 

1998; Wilson et al., 1973). Using commercial remote-sensing data, Mitchell et al. (1999) 

estimated a range of 280,000 bbl to 700,000 bbl per year with an average of 490,000 bbl for the 

northern GOM, excluding the Bay of Campeche. Using this estimate and assuming seep scales 

are proportional to surface area, the NRC (2003) estimated annual seepage for the entire GOM at 

about 980,000 bbl per year. As seepage is a natural occurrence, the rate is expected to remain the 

same throughout the 40-year analysis period

Trends in Reported Spill Volumes and Numbers

Databases on spills that have occurred in the GOM are not comprehensive. As almost 38 percent 

of all U.S. spills have occurred within the waters of the GOM and Gulf Coast States, the trends 

for all U.S. spills is assumed to be representative of trends in spills that have occurred in the 

northern GOM. The following is a summary of what is known about trends in U.S. spill risk and 

is derived from USCG data through 2004. Comprehensive data on spills for 2005 is not yet 

available (USDOT, Coast Guard, 2007): 

Volumes 

• The volume of reported spill incidents in U.S. waters has been on a steady 

downward trend since 1973. There has been a general downward trend in the 

number of spills over 24 bbl (1,000 gallons). 

• There has been no oil spills reported over 23,810 bbl (1 million gallons) since 

1991. The total volume spilled in 2003 is at the lowest amount in over 25 years. 

• The majority of reported spills since 1973 involved discharges between 0.024 

and 2.4 bbl (1 and 100 gallons). 

• The decline in oil-spill volume, particularly in the face of growing domestic 

demand for imported oil, represents the combined effects of an increasingly 

effective campaign of positive prevention and preparedness initiatives to protect 

U.S. coastal waters from oil pollution. 

Number 

• Prior to 2002, the total number of reported spill incidents remained relatively 

constant from year to year. 

• The total number of reported spill incidents dropped dramatically in 2002 and 

remained relatively constant from 2002 to 2004. 

Location 

• Most (74.6%) of all reported spills from 1973 to 2004 occurred within 3 nmi of 

shore. 

• Most (83.6%) of the volume of all reported spills occurred in waters within 3 

nmi of shore. 

Sources 

• Spills from tank vessels (ships/barges) account for the majority of volume 

spilled: 46.7 percent of the volume of oil spilled from 1973 to 2004 came from 

tank vessels; 22 percent from facilities and other non-vessels; 17.3 percent from 

pipelines; 7.7 percent from mystery spills; and 6 percent from non-tank vessels. 

• 33.1 percent of the number of all spills from 1973 to 2004 occurred from nontank vessels; 25.1 percent were “mystery” spills; 28.8 percent were from 

facilities and other non-vessels; 9.8 percent were from tank vessels (ships and 

barges carrying oil); and 3.2 percent were from pipelines. 

• The rates for oil spills ∃1,000 bbl from OCS platforms, tankers, and barges 

continues to decline. 
41

Types of Oil 

• A combination of crude oil and heavy oil is the type of oil with the greatest 

volumes spilled (61.7%). 

• Crude oil and heavy oil were the most frequent types of oil spilled (34.7% of 

the number of spills from 1973 to 2004 were the discharge of crude oil or heavy 

oil). 

Inspection and Enforcement 

The OCSLA authorizes and requires MMS to provide for both an annual scheduled inspection 

and a periodic unscheduled (unannounced) inspection of all oil and gas operations on the OCS. 

The inspections are to assure compliance with all regulatory constraints that allowed 

commencement of the operation. 

The primary objective of an initial inspection is to assure proper installation of mobile drilling 

units and fixed structures, and proper functionality of their safety and pollution prevention 

equipment. After operations begin, additional announced and unannounced inspections are 

conducted. Unannounced inspections are conducted to foster a climate of safe operations, to 

maintain an MMS presence, and to focus on operators with a poor performance record. These 

inspections are also conducted after a critical safety feature has previously been found defective. 

Poor performance generally means that more frequent, unannounced inspections may be 

conducted on a violator’s operation. 

The annual inspection examines all safety equipment designed to prevent blowouts, fires, spills, 

or other major accidents. These annual inspections involve the inspection for installation and 

performance of all platform safety-system components. 

The inspectors follow the guidelines as established by the regulations, API RP 14C, and the 

specific MMS-approved plan. The MMS inspectors perform these inspections using a national 

checklist called the Potential Incident of Noncompliance (PINC) list. This list is a compilation of 

yes/no questions derived from all regulated safety and environmental requirements. The MMS 

administers an active civil penalties program (30 CFR 250, Subpart N). A civil penalty in the 

form of substantial monetary fines may be issued against any operator that commits a violation 

that may constitute a threat of serious, irreparable, or immediate harm or damage to life, property, 

or the environment. The MMS may make recommendations for criminal penalties if a willful 

violation occurs. In addition, the regulation at 30 CFR 250.173(a) authorizes suspension of any 

operation in the GOM Region if the lessee has failed to comply with a provision of any applicable 

law, regulation, or order or provision of a lease or permit. Furthermore, the Secretary may invoke 

his authority under 30 CFR 250.185(c) to cancel a nonproductive lease with no compensation. 

Exploration and development activities may be canceled under 30 CFR 250.182 and 250.183. 

Pollution Prevention 

Pollution prevention is addressed through proper design and requirements for safety devices. The 

MMS regulations at 30 CFR 250.400 require that the operator take all necessary precautions to 

keep its wells under control at all times. The lessee is required to use the best available and safest 

drilling technology in order to enhance the evaluation of conditions of abnormal pressure and to 

minimize the potential for the well to flow or kick. Redundancy is provided for critical safety 

devices that will shut off flow from the well if loss of control is encountered. 

In addition, MMS regulations at 30 CFR 250.500, 250.600, and 250.800 require that the lessee 

assure the safety and protection of the human, marine, and coastal environments during 

completion, workover, and production operations. All production facilities, including separators, 

treaters, compressors, headers, and flowlines are required to be designed, installed, tested, 

maintained, and used in a manner that provides for efficiency, safety of operations, and protection 

of the environment. Wells, particularly subsea wells, include a number of sensors that help in 

detecting pressures and the potential for leaks in the production system. Safety devices are 
42

monitored and tested frequently to ensure their operation, should an incident occur. To ensure that 

safety devices are operating properly, MMS incorporates the American Petroleum Institute (API) 

Recommended Practice (RP) 14C into the operating regulations. API RP 14C incorporates the 

knowledge and experience of the oil and gas industry regarding the analysis, design, installation, 

and testing of the safety devices used to prevent pollution. API RP 14C presents proven practices 

for providing these safety devices for offshore production platforms. Proper application of these 

practices, along with good design, maintenance, and operation of the entire production facility, 

should provide an operationally safe and pollution-free production platform. 

Also, MMS regulations at 30 CFR 250.1000 require that pipelines and associated valves, flanges, 

and fittings be designed, installed, operated, maintained, and abandoned to provide safe and 

pollution-free transportation of fluids in a manner that does not unduly interfere with other uses 

on the OCS. 

The MMS regulation at 30 CFR 250.300(a) requires that lessees not create conditions that will 

pose an unreasonable risk to public health, life, property, aquatic life, wildlife, recreation, 

navigation, commercial fishing, or other uses of the ocean during offshore oil and gas operations. 

The lessee is required to take measures to prevent the unauthorized discharge of pollutants into 

the offshore waters. Control and removal of pollution is the responsibility and at the expense of 

the lessee. Immediate corrective action to a pollution event is required. All hydrocarbon-handling 

equipment for testing and production, such as separators, tanks, and treaters, are required to be 

designed, installed, and operated to prevent pollution. Maintenance and repairs that are necessary 

to prevent pollution is required to be taken immediately. Drilling and production facilities are 

required to be inspected daily or at intervals approved or prescribed by the MMS District 

Supervisor to determine if pollution is occurring. 

Operators are required to install curbs, gutters, drip pans, and drains on platform and rig deck 

areas in a manner necessary to collect all contaminants and debris not authorized for discharge. 

The rules also explicitly prohibit the disposal of equipment, cables, chains, containers, or other 

materials into offshore waters. Portable equipment, spools or reels, drums, pallets, and other loose 

items must be marked in a durable manner with the owner’s name prior to use or transport over 

offshore waters. Smaller objects must be stored in a marked container when not in use. 

Operational discharges such as produced water and drilling muds and cuttings are regulated by 

the USEPA through the NPDES program. The MMS may restrict the rate of drilling fluid 

discharge or prescribe alternative discharge methods. No petroleum based substances, including 

diesel fuel, may be added to the drilling mud system without prior approval of the MMS District 

Supervisor. 

Oil-Spill Response Plans 

The MMS’s responsibilities under OPA 90 include spill prevention, review, and approval of oilspill response plans (OSRP); inspection of oil-spill containment and cleanup equipment; and 

ensuring oil-spill financial responsibility for facilities in offshore waters located seaward of the 

coastline or in any portion of a bay that is connected to the sea either directly or through one or 

more other bays. The MMS regulations (30 CFR 254) require that all owners and operators of oilhandling, storage, or transportation facilities located seaward of the coastline submit an OSRP for 

approval. The term “coastline” means the line of ordinary low water along that portion of the 

coast which is in direct contact with the open sea and the line marking the seaward limit of inland 

waters. The term “facility” means any structure, group of structures, equipment, or device (other 

than a vessel), which is used for one or more of the following purposes: exploring for, drilling for, 

producing, storing, handling, transferring, processing, or transporting oil. A MODU is classified 

as a facility when engaged in drilling or downhole operations. 

The regulation at 30 CFR 254.2 requires that an OSRP must be submitted and approved before an 

operator can use a facility. The MMS can grant an exception to this requirement during the MMS 

review of an operator’s submitted OSRP. In order to be granted this exception during this time 
43

period, an owner/operator must certify in writing to MMS that it is capable of responding to a 

“worst-case” spill or the substantial threat of such a spill. To continue operations, the facility 

must be operated in compliance with the approved OSRP or the MMS-accepted “worst-case” 

spill certification. Owners or operators of offshore pipelines are required to submit an OSRP for 

any pipeline that carries oil, condensate, or gas with condensate; pipelines carrying essentially dry 

gas do not require an OSRP. Current OSRP’s are required for abandoned facilities until they are 

physically removed or dismantled. 

The OSRP describes how an operator intends to respond to an oil spill. The OSRP may be site 

specific or regional (30 CFR 254.3). The term “regional” means a spill response plan that covers 

multiple facilities or leases of an owner or operator, including affiliates, which are located in the 

same MMS GOM Region. Although Regional OSRP’s have not been allowed for facilities 

subject to the State of Florida consistency review in the past, MMS has recently initiated a new 

policy accepting subregional plans for this area. The subregional plan concept is similar to the 

regional concept, which allows leases or facilities to be grouped together for the purposes of (1) 

calculating response times, (2) determining quantities of response equipment, (3) conducting oilspill trajectory analyses, (4) determining worst-case discharge scenarios, and (5) identifying areas 

of special economic and environmental importance that may be impacted and the strategies for 

their protection. The number and location of the leases and facilities allowed to be covered by a 

subregional OSRP will be decided by MMS on a case-by-case basis considering the proximity of 

the leases or facilities proposed to be covered. NTL 2006-G21 includes guidance on the 

preparation and submittal of subregional OSRP’s. 

The Emergency Response Action Plan within the OSRP serves as the core of the MMS required 

OSRP. In accordance with 30 CFR 254.23, the Emergency Response Action Plan requires 

identification of (1) the qualified individual and the spill-response management team, (2) the 

spill-response operating team, (3) the oil-spill response removal organizations under contract for 

response, and (4) the Federal, State, and local regulatory agencies that an owner/operator must 

notify or that they must consult with to obtain site-specific environmental information when an 

oil spill occurs. The OSRP is also required to include an inventory of appropriate equipment and 

materials, their availability, and the time needed for deployment, as well as information 

pertaining to dispersant use, in situ burning, a worse-case discharge scenario, contractual 

agreements, and training and drills. The response plan must provide for response to an oil spill 

from their facility and the operator must immediately carry out the provisions of the plan 

whenever an oil spill from the facility occurs. The OSRP must be in compliance with the National 

Contingency Plan and the Area Contingency Plan(s) (ACP). The operator is also required to carry 

out the training, equipment testing, and periodic drills described in the OSRP. All MMS-approved 

OSRP’s must be reviewed at least every two years. 

Memorandum of Understanding and Memoranda of Agreements Between MMS and Coast 

Guard 

Since the MMS and USCG have closely related jurisdiction over different aspects of safety and 

operations on the OCS, the agencies have established a formal MOU that delineates lead 

responsibilities for managing OCS activities in accordance with OCSLA, as amended, and OPA 

90. The latest MOU, dated September 30, 2004, supersedes the August 1989 and December 1998 

versions of the interagency agreement. The MOU is designed to minimize duplication and 

promote consistent regulation of facilities under the jurisdiction of both agencies. A 

Memorandum of Agreement (MOA) OCS No.1—Agency Responsibilities, between MMS and 

USCG, dated September 30, 2004, further clarifies the technical and process section of the 

MMS/USCG MOU. The MOA requires the participating agencies to review their internal 

procedures and, where appropriate, revise them to accommodate the provisions of the September 

2004 MOA. To facilitate coordination with USCG, MMS has established a full-time position 

within the Office of Offshore Regulatory Programs to provide liaison between the agencies. 
44

Generally, the MOU identifies MMS as the lead agency for matters concerning the equipment 

and operations directly involved in the production of oil and gas. These include, among others, 

design and operation of risers, permanent mooring foundations of the facility, drilling and well 

production and services, inspection and testing of all drilling-related equipment, and platform 

decommissioning. Issues regarding certain aspects of safe operation of the facility, its systems, 

and equipment generally fall under the jurisdiction of the USCG. These include, among others, 

design of vessels, their seakeeping characteristics, propulsion and dynamic positioning systems, 

supply and lightering procedures and equipment, utility systems, safety equipment and 

procedures, and pollution prevention and response procedures. In 2002, MMS was authorized to 

inspect USCG-related safety items on fixed facilities on the OCS. 

Generally, the MOA identifies agency responsibilities (i.e., agency representatives for the 

purpose of keeping each other informed of issues, relevant applications, routine policy 

determinations and to coordinate joint activities), civil penalties (i.e., USCG refers civil penalty 

cases to the MMS), oil-spill financial responsibility (OSFR) (i.e., MMS determines and provides 

OSFR-related information to the USCG upon request), oil-spill preparedness and response 

planning (i.e., MMS requires responsible parties to maintain approved oil-spill-response plans 

consistent with Area Contingency Plans and the National Contingency Plan; personnel receive 

training and response equipment is inspected; jointly approve floating oil storage facilities; and 

advise MMS of spill-response activities), oil-spill response (i.e., reporting all spills to the 

National Response Center and direct measures to abate sources of pollution from an OCS 

facility), accident investigations (i.e., MMS and USCG responsible for investigating and 

preparing report of fires, spillage, injury, fatality and blowouts and collisions and allisions), and 

offshore facility system/subsystem responsibility matrix (identifies lead agency responsible for 

MODU, fixed, and floating systems and subsystem and coordinates with other agencies as 

appropriate). On April 18, 2005, MMS and USCG met to identify MOA’s that needed to be 

developed and to prioritize work. The following subject areas were selected: (a) civil penalties; 

(b) incident investigations; (c) offshore security; (d) oil-spill planning, preparedness, and 

response; (e) deepwater ports; (f) digital databases; (g) mobile offshore drilling units (MODU’s); 

(h) fixed platforms; (i) floating platforms; (j) floating, production, storage, and offloading units 

(FPSO’s); and (k) incident reporting. Joint agency teams have been established to develop the 

MOA’s for the first five subject areas. In addition, an MOA is also being pursued to address 

renewable energy and alternate use of the OCS. The Civil Penalties MOA was approved on 

September 12, 2006. The Oil-Spill Planning MOA has been drafted and is under legal counsel 

review with USCG and DOI. The Incident Investigation MOA has undergone regional review and 

is proceeding toward finalization. 

The Oil Pollution Act 

The Oil Pollution Act of 1990 (OPA or OPA 90) (33 U.S.C. 2701 et seq.) is comprehensive 

legislation that includes, in part, provisions to (1) improve oil-spill prevention, preparedness, and 

response capability; (2) establish limitations on liability for damages resulting from oil pollution; 

and (3) implement a fund for the payment of compensation for such damages. 

The OPA, in part, revised Section 311 of the CWA to expand Federal spill-response authority; 

increase penalties for spills; establish U.S. Coast Guard (USCG), prepositioned, oil-spill response 

equipment sites; require vessel and facility response plans; and provide for interagency 

contingency plans. Many of the statutory changes required corresponding revisions to the 

National Oil and Hazardous Substances Pollution Contingency Plan. 

If a spill or substantial threat of a spill of oil or a hazardous substance from a vessel, offshore 

facility, or onshore facility is considered to be of such a size or character to be a substantial threat 

to the public health or welfare of the U.S., under provisions of the Act, the President (through the 

USCG) now has the authority to direct all Federal, State, and private actions to remove a spill or 

to mitigate or prevent the threat of the spill. Potential impacts from spills of oil or a hazardous 

substance to fish, shellfish, wildlife, other natural resources, or the public and private beaches of 
45

the U.S. would be an example of the degree or type of threat considered to be of such a size or 

character to be a substantial threat to the U.S. public health or welfare. In addition, the USCG’s 

authority to investigate marine accidents involving foreign tankers was expanded to include 

accidents in the Exclusive Economic Zone (EEZ). The Act also established USCG oil-spill, 

district response groups (including equipment and personnel) in each of the 10 USCG districts, 

with a national response unit, the National Strike Force Coordination Center, located in Elizabeth 

City, North Carolina. 

The OPA strengthened spill planning and prevention activities by providing for the establishment 

of interagency spill contingency plans for areas of the U.S. To achieve this goal, Area 

Committees composed of qualified Federal, State, and local officials were created to develop 

Area Contingency Plans. The OPA mandates that contingency plans address the response to a 

“worst case” oil spill or a substantial threat of such a spill. It also required that vessels and both 

onshore and offshore facilities have response plans approved by the President. These plans were 

required to adhere to specified requirements, including the demonstration that they had contracted 

with private parties to provide the personnel and equipment necessary to respond to or mitigate a 

“worst case” spill. In addition, the Act provided for increased penalties for violations of statutes 

related to oil spills, including payment of triple costs by persons who fail to follow contingency 

plan requirements. 

The Act further specifies that vessel owners, not cargo owners, are liable for spills and raises the 

liability limits from $150 (dollars) per gross ton to $1,200 per gross ton for vessels. The 

maximum liability for offshore facilities is set at $75 million plus unlimited removal costs; 

liability for onshore facilities or a deepwater port is set at $350 million. Willful misconduct, 

violation of any Federal operating or safety standard, failure to report an incident, or refusal to 

participate in a cleanup subjects the spiller to unlimited liability under provisions of the Act. 

Pursuant to the Act, double hulls are required on all newly constructed tankers. Double hulls or 

double containment systems are required on all tank vessels less than 5,000 gross tons (i.e., 

barges). Since 1995, existing single-hull tankers are being phased out based on size and age. 

An Interagency Coordinating Committee on Oil Pollution Research was established by the 

provisions of the Act and tasked with submitting a plan for the implementation of an oil-pollution 

research, development, and demonstration program to Congress. The plan was submitted to 

Congress in April 1992. This program addressed, in part, an identification of important oilpollution research gaps, an establishment of research priorities and goals, and an estimate of the 

resources and timetables necessary to accomplish the identified research tasks. In 1992, the 

program plan was also provided to the Marine Board of the National Research Council for review 

and comment as required by OPA 90. Upon review, the Marine Board recommended that the plan 

be revised using a framework that addresses spill prevention, human factors, and field testing 

demonstration of developed response technology. This was accomplished in April, 1997. 

In October 1991, Executive Order 12777 delegated the provisions of OPA to various departments 

and agencies within the U.S. Government, including the USCG, USEPA, U.S. Department of 

Transportation (USDOT or DOT), and DOI. The Secretary was delegated Federal Water 

Pollution Control Act authority over offshore facilities and associated pipelines (except 

deepwater ports) for all Federal and State waters. The Secretary’s functions under the Executive 

Order include spill prevention, Oil Spill Contingency Plans (OSCP’s), equipment, financial 

responsibility certification, and civil penalties. 

The Oil Spill Liability Trust Fund (OSLTF), authorized under OPA and administered by the 

USCG, is available to pay for removal costs and damages not recovered from responsible parties. 

The Fund provides up to $1 billion per incident for cleanup costs and other damages. The OSLTF 

was originally established under Section 9509 of the Internal Revenue Code of 1986. It was one 

of several similar Federal trust funds funded by various levies set up to provide for the costs of 
46

water pollution. The OPA generally consolidated the liability and compensation schemes of these 

prior, Federal oil-pollution laws and authorized the use of the OSLTF, which consolidated the 

funds supporting those regimes. Those prior laws included the Federal Water Pollution Control 

Act, Trans-Alaska Pipeline Authorization Act, Deepwater Port Act, and OCSLA. On February 

20, 1991, the National Pollution Funds Center (NPFC) was commissioned to serve as fiduciary 

agent for the OSLTF. 

The OPA 90 provides that parties responsible for offshore facilities demonstrate, establish, and 

maintain oil-spill financial responsibility (OSFR) for those facilities. The OPA 90 replaced and 

rescinded the OCSLA OSFR requirements. Executive Order 12777 assigned the OSFR 

certification function to the DOI; the Secretary, in turn, delegated this function to MMS. 

The minimum amount of OSFR that must be demonstrated is $35 million for covered offshore 

facilities (COF’s) located on the OCS and $10 million for COF’s located in State waters. A COF 

is any structure and all of its components, equipment, pipeline, or device (other than a vessel or 

other than a pipeline or deepwater port licensed under the Deepwater Port Act of 1974) used for 

exploring for, drilling for, or producing oil or for transporting oil from such facilities. The 

regulation provides an exemption for persons responsible for facilities having a potential worstcase oil spill of 1,000 barrel (bbl) or less, unless the risks posed by a facility justify a lower 

threshold volume. 

The Secretary of Transportation has authority for vessel oil-pollution financial responsibility, and 

the USCG regulates the oil-spill financial responsibility program for vessels. A MODU is 

classified as a vessel. However, a well drilled from a MODU is classified as an offshore facility 

under this rule. 

Comprehensive Environmental Response, Compensation, and Liability Act 

The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 

(CERCLA) (42 U.S.C. 9601 et seq.), modified by the 1986 Superfund Amendments and 

Reauthorization Act (SARA) and Section 1006 of OPA 90, requires the promulgation of 

regulations for the assessment of natural resource damages from oil spills and hazardous 

substances. These Acts provide for the designation of trustees who determine resource injuries, 

assess natural resource damages (including the costs of assessing damages), present claims, 

recover damages, and develop and implement plans for the restoration, rehabilitation, 

replacement, or acquisition of the equivalent of the injured natural resources under the 

trusteeship. 

The DOI was given the authority under CERCLA to develop regulations and procedures for the 

assessment of damages for natural resource injuries resulting from the release of a hazardous 

substance or oil spills (Natural Resource Damage Assessment (NRDA) Regulations). These 

rulemakings are all codified at 43 CFR 11. The CERCLA specified two types of procedures to be 

developed: type “A” procedures for simplified, standard assessments requiring minimal field 

observations in cases of minor spills or releases in certain environments; and type “B” sitespecific procedures for detailed assessments for individual cases.

Spill Response 

MMS Spill Response Requirements and Initiatives 

To ensure that industry maintains effective oil-spill-response capabilities, MMS 

• requires immediate notification for spills >1 bbl—all spills require notification 

to the USCG and MMS receives notification from the USCG of all spills #1 bbl; 

• conducts investigations to determine the cause of a spill; 
47

• assesses civil and criminal penalties, if needed; 

• oversees spill source control and abatement operations by industry; 

• sets requirements and reviews and approves oil-spill response plans for offshore 

facilities; 

• conducts unannounced drills to ensure compliance with oil-spill response plans; 

• requires operators to ensure that their spill-response operating and management 

teams receive appropriate spill-response training; 

• conducts inspections of oil-spill response equipment; 

• requires industry to show financial responsibility to respond to possible spills; 

and 

• provides research leadership to improve the capabilities for detecting and 

responding to an oil spill in the marine environment. 

Offshore Response and Cleanup Technology 

A number of cleanup techniques are available for response to an oil spill. Open-water response 

options include mechanical recovery, chemical dispersion, in-situ burning, or natural dispersion. 

Although bioremediation was at one time considered for use in open water, studies have shown 

that this technique is not an effective spill-response option in open water because of the high 

degree of dilution of the product and the rapid movement of oil in open water. Effective use of 

bioremediation requires that the products remain in contact with the oil for extended periods of 

time. 

Single or multiple spill-response cleanup techniques may be used in abating a spill. The cleanup 

technique chosen for a spill response will vary depending upon the unique aspects of each 

situation. The selected mix of countermeasures will depend upon the shoreline and natural 

resources that may be impacted; the size, location, and type of oil spilled; weather; and other 

variables. The overall objective of on-water recovery is to minimize the risk of impact by 

preventing the spread of free-floating oil. The physical and chemical properties of crude oil can 

greatly affect the effectiveness of containment and recovery equipment, dispersant application, 

and in-situ burning. It is expected that oil found in the proposed lease sale areas could range from 

medium-weight oil to condensates. 

Mechanical Cleanup 

Generally, mechanical containment and recovery is the primary oil-spill-response method used 

(33 CFR 153.305(a)). Mechanical recovery is the process of using booms and skimmers to pick 

up oil from the water surface. In a typical offshore oil-spill scenario, a boom is deployed in a V, J, 

or U configuration to gather and concentrate oil on the surface of the water. The oil is gathered in 

the wide end of the boom (front) and travels backward toward the narrow apex of the boom 

(back). The skimmer is positioned at the apex of the boom, where the oil is the thickest. The 

skimmer recovers the oil by sucking in the top layer via a weir skimmer, or the oil adheres to and 

is removed from a moving surface (i.e., an oleophylic skimmer). The oil is then pumped from the 

skimmer to temporary storage on an attendant vessel or barge, the latter of which serves as the 

skimming platform. When this on-board storage is full, the oil must be pumped into a larger 

storage vessel. 

Mechanical oil-spill-response equipment that is contractually available to the operators through 

Oil Spill Removal Organization (OSRO) membership or contracts would be called out to respond 

to an offshore spill in the proposed lease sale areas. Each individual operator’s response to a spill 
48

would differ according to the location of the spill, the volume and source of the spill, the OSRO 

under contract, etc. At this time, in the Gulf of Mexico, there are three major OSRO’s that can 

respond to spills in the open ocean: (1) Clean Gulf Associates, (2) Marine Spill Response 

Corporation (MSRC), and (3) National Response Corporation. The equipment owned by these 

OSRO’s is strategically located near the busier port areas throughout the Gulf to service the oil 

and gas exploration and production operators and, in some cases, the marine transportation 

industry. Numerous smaller OSRO’s that stockpile additional shoreline and nearshore response 

equipment are also located throughout the Gulf coastal area. 

It is expected that the oil-spill-response equipment needed to respond to an offshore spill in the 

proposed lease sale areas could be called out from one or more of the following oil-spill 

equipment base locations: Corpus Christi, Aransas Pass, Houston, La Porte, Ingleside, Port 

Arthur, and Galveston, Texas; Lake Charles, New Iberia, Belle Chase, Cameron, Cocodrie, 

Morgan City, New Orleans, Sulphur, Houma, Fourchon, Fort Jackson, and Venice, Louisiana; 

Pascagoula, Mississippi; Theodore and Mobile, Alabama; or Pensacola, Ft. Lauderdale, Panama 

City, and Tampa, Florida. Response times for any of this equipment would vary, dependent on 

the location of the equipment, the staging area, and the spill site; and on the transport 

requirements for the type of equipment procured. 

It is assumed that 10-30 percent of an oil spill in an offshore environment can be mechanically 

removed from the water prior to the spill making landfall (U.S. Congress, Office of Technology 

Assessment, 1990). 

Should an oil spill occur during a storm, spill response from shore would occur following the 

storm. Spill response would not be possible while storm conditions continued, given the sea state 

limitations for skimming vessels and containment boom deployment. However, oil released onto 

the ocean surface during a storm event would be subject to accelerated rates of weathering and 

dissolution (i.e., oil and water would be agitated, forcing oil into smaller droplets and facilitating 

dissolution of the high end aromatic compounds present). 

Dispersants 

When dispersants are applied to spilled crude oil, the surface tension of the oil is reduced. This 

allows normal wind and wave action to break the oil into tiny droplets, which are dispersed into 

the upper portion of the water column. Natural processes then break down these droplets much 

quicker than they would if the oil were allowed to remain on the water surface. 

Dispersant use must be in accordance with the Regional Response Teams’ Preapproved 

Dispersant Use Manual and any conditions outlined within a Regional Response Team sitespecific dispersant approval given after a spill event. Consequently, dispersant use would be in 

accordance with the restrictions for specific water depths, distances from shore, or monitoring 

requirements. For a deepwater >1,000 ft water depth) spill ∃1,000 bbl, dispersant application may 

be a preferred response in the open water environment to prevent oil from reaching a coastal area, 

in addition to mechanical response. 

Based on the present location of dispersant stockpiles and dispersant application equipment in the 

GOM, it is expected that the dispersant application aircraft initially called out for an oil-spill 

response to an offshore spill in the proposed lease sale area will come from Houma, Louisiana; 

Stennis, Mississippi; or Coolidge, Arizona. The dispersants will come from locations primarily in 

Texas and Louisiana. Response times for this equipment would vary, depending on the spill site 

and on the transport time for additional supplies of dispersants to arrive at a staging location. 

Based on historic information, this EIS assumes that dispersant application will be effective on 

20-50 percent (S.L. Ross Environmental Research Ltd., 2000) of the treated oil. 

Should an oil spill occur during a storm, dispersant application would occur following the storm. 

Aerial and vessel dispersant application would not be possible while storm conditions continued. 
49

However, oil released onto the ocean surface during a storm event would be subject to accelerated 

rates of weathering and dissolution (i.e., oil and water would be agitated, forcing oil into smaller 

droplets and facilitating dissolution of the high-end aromatic compounds present). 

In-situ Burning 

In-situ burning is an oil-spill cleanup technique that involves the controlled burning of the oil at 

or near a spill site. The use of this spill-response technique can provide the potential for the 

removal of large amounts of oil over an extensive area in less time than other techniques. In-situ 

burning involves the same oil collection process used in mechanical recovery, except instead of 

going into a skimmer, the oil is funneled into a fire-boom, a specialized boom that has been 

constructed to withstand the high temperatures from burning oil. Fire resistant booms are used to 

isolate the oil from the source of the slick. The oil in the fire-boom is then ignited and allowed to 

burn. While in-situ burning is another method for disposing of oil that has been collected in a 

boom, this method is typically more effective than skimmers when the oil is highly concentrated. 

For oil to ignite on water, it must be at least 2-3 mm thick. Most oils must be contained with 

fireproof boom to maintain this thickness. Oils burn at a rate of 3-4 mm per minute. Most oils will 

burn, although emulsions may require treatment before they will burn. Water in the oil will affect 

the burn rate; however, recent research has indicated that this effect will be marginal. One 

approximately 200—m length of fire resistant boom can contain up to 355 bbl (11,000 gallons) of 

oil, which takes about 45 minutes to burn. In total, it would take about three hours to collect this 

amount of oil, tow it away from a slick, and burn it (Fingas, 2001). Response times for bringing a 

fire-resistant boom onsite would vary, dependent on the location of the equipment, the staging 

area, and the spill site. 

Should an oil spill occur during a storm, in-situ burning would occur following the storm. In-situ 

burning would not be possible while storm conditions continued. 

Natural Dispersion 

In some instances, the best response to a spill may be to allow the natural dispersion of a slick to 

occur. Natural dispersion may be a preferred option for smaller spills of lighter nonpersistent oils 

and condensates that form slicks that are too thin to be removed by conventional methods and are 

expected to dissipate rapidly, particularly if there are no identified potential impacts to offshore 

resources and a potential for shoreline impact is not indicated. In addition, natural dispersion may 

also be a preferred option in some nearshore environments when the potential damage caused by 

a cleanup effort could cause more damage than the spill itself.

Onshore Response and Cleanup 

Offshore response and cleanup is preferable to shoreline cleanup; however, if an oil slick reaches 

the coastline it is expected that the specific shoreline cleanup countermeasures identified and 

prioritized in the appropriate Area Contingency Plans (ACP’s) for various habitat types would be 

used. The sensitivity of the contaminated shoreline is the most important factor in the 

development of cleanup recommendations. Shorelines of low productivity and biomass can 

withstand more intrusive cleanup methods such as pressure washing. Shorelines of high 

productivity and biomass are very sensitive to intrusive cleanup methods, and in many cases, the 

cleanup is more damaging than allowing natural recovery. 

Oil-spill response planning in the United States is accomplished through a mandated set of 

interrelated plans. The ACP represents the third tier of the National Response Planning System 

and was mandated by OPA 90. The ACP’s cover subregional geographic areas. The ACP’s are a 

focal point of response planning, providing detailed information on response procedures, 

priorities, and appropriate countermeasures. The Gulf coastal area that falls within USCG District 

8 is covered by the One Gulf Plan ACP, which includes separate Geographic Response Plans for 

areas covered by USCG Sector Corpus Christi, Sector Houston/Galveston, Sector Port Arthur, 

Sector Morgan City, Sector New Orleans, and Sector Mobile. The Miami ACP covers the 

remaining Gulf coastal area. The ACP’s are written and maintained by Area Committees 
50

assembled from Federal, State, and local governmental agencies that have pollution response 

authority; nongovernmental participants may attend meetings and provide input. The coastal Area 

Committees are chaired by respective Federal On-Scene Coordinators from the appropriate 

USCG Office and are comprised of members from local or area-specific jurisdictions. Response 

procedures identified within an ACP or its Geographic Response Plan(s) reflect the priorities and 

procedures agreed to by members of the Area Committees. 

The single most frequently recommended spill-response strategy for the areas identified for 

protection in all of the applicable ACP’s or it’s Geographic Response Plans is the use of a 

shoreline boom to deflect oil away from coastal resources such as seagrass beds, marinas, resting 

areas for migratory birds, bird and turtle nesting areas, etc. If a shoreline is oiled, the selection of 

the type of shoreline remediation to be used will depend on the following: (1) the type and 

amount of oil on the shore; (2) the nature of the affected coastline; (3) the depth of oil penetration 

into the sediments; (4) the accessibility and the ability of vehicles to travel along the shoreline; 

(5) the possible ecological damage of the treatment to the shoreline environment; (6) weather 

conditions; (7) the current state of the oil; and (8) jurisdictional considerations. 

Shoreline Cleanup Countermeasures 

The following assumptions regarding the cleanup of spills that contact coastal resources in the 

area of consideration reflect a generalization of the site-specific guidance provided in the ACP’s 

or its Geographic Response Plans applicable to the GOM. As stated in Chapter 4.3.1.4, for this 

analysis it is expected that typical oil spilled as a result of an accident associated with a proposed 

action would be within the range of 30-35 degrees API. Since the following discussion is 

intended to address the most likely spill scenario discussed in Chapter 4.3.5.3, cleanup 

countermeasures for a medium-weight oil are all that are included in the following discussion. 

The ACP’s applicable to the Gulf coastal area cover a vast geographical area. The differences in 

the response priorities and procedures among the various ACP’s or its Geographic Response 

Plans reflect the differences in the identified resources needing spill protection in the area covered 

by each ACP or its Geographic Response Plans: 

• Barrier Island/Fine Sand Beaches Cleanup: After the oiling of a barrier 

island/fine sand beach with a medium-weight oil, applicable cleanup options are 

manual removal, trenching (recovery wells), sediment removal, cold-water 

deluge flooding, shore removal/replacement, and warm-water washing. Other 

possible shoreline countermeasures include low-pressure cold-water washing, 

burning, and nutrient enhancement. Responders are requested to avoid the 

following countermeasures: no action; passive collection (sorbents); highpressure, cold-water washing; hot-water washing; slurry sand blasting; vacuum; 

and vegetation cutting. 

• Fresh or Salt Marsh Cleanup: In all cases, cleanup options that avoid causing 

additional damage to the marshes will be selected. After the oiling of a fresh or 

salt marsh with a medium-weight oil, the preferred cleanup option would be to 

take no action. Another applicable alternative would be trenching (recovery 

wells). Shore removal/replacement, vegetation cutting, or nutrient enhancement 

could be used. The option of using vegetation cutting as a shoreline 

countermeasure will depend upon the time of the year and will be considered 

generally only if re-oiling of birds is possible. Chemical treatment, burning, and 

bacterial addition as countermeasures are under consideration. Responders are 

advised to avoid manual removal, passive collection, debris removal/heavy 

equipment, sediment removal, cold-water flooding, high- or low-pressure coldwater washing, warm-water washing, hot-water washing, slurry sand blasting, 

and shore removal/replacement. 
51

• Coarse Sand/Gravel Beaches Cleanup: After the oiling of a coarse sand/gravel 

beach with a medium-weight oil applicable cleanup options are manual removal, 

trenching (recovery wells), sediment removal, cold-water deluge flooding, and 

shore removal/ replacement. Other possible shoreline countermeasures include 

low-pressure, coldwater washing; burning; warm-water washing; and nutrient 

enhancement. Responders are requested to avoid the following countermeasures: 

no action; passive collection (sorbents); high-pressure, cold-water washing; hotwater washing; slurry sand blasting; vacuum; and vegetation cutting. 

• Exposed or Sheltered Tidal Flats Cleanup: After the oiling of an exposed or 

sheltered tidal flat with a medium-weight oil, the preferred cleanup option is no 

action. Other applicable shoreline countermeasures for this resource include 

trenching (recovery wells) and cold-water deluge flooding. Other possible 

shoreline countermeasures listed include low-pressure, cold-water washing; 

vacuum; vegetation cutting; and nutrient enhancement. Responders are requested 

to avoid manual removal; passive collection; debris removal/heavy equipment; 

sediment removal; high-pressure, cold-water washing; warm-water washing; hotwater washing; slurry sand blasting; and shore removal replacement. 

• Seawall/Pier Cleanup: After the oiling of a seawall or pier with a mediumweight oil, the applicable cleanup options include manual removal; cold-water 

flooding; low- and high-pressure, cold-water washing; warm-water washing; hotwater washing; slurry sand blasting; vacuum; and shore removal replacement. 

Other possible shoreline countermeasures listed include burning and nutrient 

enhancement. Responders are requested to avoid no action, passive collection 

(sorbents), trenching, sediment removal, and vegetation cutting.

Mitigation in Response to USFWS Conservation Recommendations

The following mitigating measures were recommended by FWS in their Central Planning Area 

(CPA) and Western Planning Area (WPA) Biological Opinion and have been adhered to by 

MMS: 

Oil Spill and Other Hazardous Emergency Contingency Plans ─ In order to reduce impacts 

on threatened and endangered species, MMS will continue to require the petroleum industry to 

prepare adequate hazardous spill contingency plans for all activities. This will include the 

strategic placement of appropriate spill cleanup equipment, personnel training in non-intrusive 

cleanup techniques, and demonstration of response commitment, capabilities, and 

implementation. The response plans will include, but are not limited to, identification of the 

identified species' habitat (including designated critical habitat), oil-spill trajectory modeling to 

ascertain the time for oil to reach the habitats, implementation plans for protection of the species 

and their habitats in case of an oil spill, cleanup methods, and State and Federal resource manager 

contacts. Several of the mitigation measures listed above have been put into place since the 2002 

USFWS Biological Opinion. Consideration of threatened and endangered species is a stated 

requirement. Also, the Final Rule on Protection of Marine Mammals and Threatened and 

Endangered Species, issued on April 16, 2007, requires Federal oil and gas lessees in the OCS to 

provide information on how their activities will conform to the requirements of the Endangered 

Species Act and the Marine Mammal Protection Act. The Protected Species Lease Stipulation 

states: 

The MMS will require oil spill contingency planning to identify important 

habitats, including designated critical habitat, used by listed species (e.g. sea 

turtle nesting beaches, piping plover critical habitat), and require the strategic 
52

placement of spill cleanup equipment to be used only by personnel trained in 

less-intrusive cleanup techniques on beach and bay shores.

The MMS will ensure that oil spill contingency plans are prepared to meet the requirements of the 

agency, identify specific locations on nesting beaches utilized by sea turtles, and include 

provisions for removal of sea turtle eggs from beaches that are imminently expected to receive 

spilled oil. The eggs should be relocated and incubated and the hatchlings released in an 

uncontaminated area. The plan should also name qualified and permitted rehabilitators to handle 

oiled and/or stranded sea turtles. 

Further, MMS will coordinate annually with the U.S. Coast Guard (USCG) to assure that the spill 

contingency and response plans contain current and up-to-date sensitive areas information 

regarding the Kemp’s ridley and loggerhead sea turtle, piping plover, bald eagle, and brown 

pelican. An updated MOU with the USCG was signed in May 2007 to continue and improve 

coordination of industry activities and rapid response should a spill occur. 

Aircraft Impacts ─ To minimize impacts to endangered and threatened species, MMS 

advises the lessees' aircraft operators to adhere to the altitude restrictions over National 

Wildlife Refuges (NWR) and parks (including national seashores). Federal Aviation 

Administration requirements, as well as corporate helicopter guidelines, give minimum 

altitudes for aircraft flying over sensitive areas. 

Marine Debris and Trash ─ The MMS will continue to enforce their regulations 

regarding marine debris disposal from offshore oil and gas operations (NTL 86-11) and 

promulgated regulations (30 Code of Federal Regulations (CFR) 250.40). These 

regulations are to assure that lessees do not create conditions that will pose an 

unreasonable risk to public health, life, property, aquatic life, wildlife, recreation, 

navigation, commercial fishing, or other uses of the ocean during offshore oil and gas 

operations. 

MMS issued the Marine Debris Awareness and Elimination NTL in 2003. This NTL 

requires annual marine debris awareness training for all offshore personnel. Placards that 

bring attention to marine debris, and the unintentional contribution to debris from 

accidental loss, are required to be posted on vessels and structures. 

Species Studies ─ The MMS contributed funding to the Piping Plover Conference held 

in Georgia in 2005. Those Proceedings are not yet available. The hurricanes of 2004 and 

2005 altered habitat, particularly the sea turtle nesting areas of the Chandeleur Islands. 

MMS will consider funding requests for studies to assess the status and impacts on sea 

turtles and Gulf sturgeon. 

Findings of Affect

The analyses of the potential impacts are based on a scenario for a typical proposed action. These 

scenarios provide assumptions and estimates on the amounts, locations, and timing for OCS 

exploration, development, and production operations and facilities, both offshore and onshore and 

on oil spills and other accidental events. The mitigating measures are considered part of a 

proposed action for analysis purposes. There are three possible Findings of Affects: No Effect; 

May Affect – is Not Likely to Adversely Affect; and May Affect – is Likely to Adversely Affect. 
53

A determination of No Effect means there are absolutely no effects of the project, either positive 

or negative. A determination of May Affect – is Not Likely to Adversely Affect means that all 

effects are beneficial, insignificant, or discountable. Beneficial effects have contemporaneous 

positive effects without any adverse effects to the species or habitat. Insignificant effects relate to 

the size of the impact. Discountable effects are those extremely unlikely to occur. A 

determination of May Affect – is Likely to Adversely Affect means that all effects cannot be 

avoided. 

Sea Turtles 

Five sea turtles were analyzed for potential effects in the EIS: loggerhead (Caretta caretta), 

green (Chelonia mydas), leatherback (Dermochelys coriacea), Kemp’s ridley (Lepidochelys 

kempii), and hawksbill (Eretmochelys imbricata). The hawksbill sea turtle is not known to nest 

on GOM beaches in Louisiana, Mississippi, or Alabama and only rarely nests on the GOM coast 

of Florida; in 1999, one nest was confirmed in Texas. Thus, because of low nesting numbers and 

the low probability of an oil spill occurring when hawksbill sea turtles and their nest would be 

present, the Finding of Affect for a proposed action on hawksbills is Not Likely to Adversely 

Affect. 

Potential sources of impacts to nesting and hatchling sea turtles from a proposed action include 

OCS related offshore and coastal oil spills, coastal and onshore spill-response activities, and trash 

and debris from OCS offshore activities. Trash and debris contribute to the degradation of 

nesting habitat and could entangle a hatchling emerging from the nest and crawling to the sea. 

Loggerhead nesting and hatchling emergence occur at night; therefore, disturbance from aircraft 

and/or boat vessel traffic would be minimal because traffic activity during this time period is 

minimal to negligible. Since Kemp’s ridley nesting and hatchling emergence occur during 

daylight hours, it is not known how this would affect nesting Kemp’s ridley sea turtles; however, 

minimal disturbance would be expected. Air emissions are not expected to be a concern for 

nesting adult sea turtles because of the limited time spent on the beach; however, impacts to 

developing embryos and hatchlings in the nest are unknown. Offshore pipeline installation is not 

expected to impact nesting sea turtles. Onshore beach installation could have an impact if 

onshore pipeline installation on sea turtle nesting beaches is conducted during the nesting season 

from May 1 through October 31; however, if a new onshore pipeline is needed, an environmental 

impact analysis is required before approval. Where pipeline landfall occurs, the permitting 

process encourages construction outside the nesting season and the use of directional boring to 

greatly reduce and potentially eliminate impacts to barrier beaches. 

Oil spills impacting the nesting beaches of sea turtles are of concern and would have a significant 

impact, depending upon the amount of weathering the oil has undergone, the height of deposition 

on the beach, and the stage of nesting. Effects of petroleum on the development and survival of 

marine turtle embryos are variable. Impacts would be different if the oil impacts the beach before 

nesting, during nest preparation, or during incubation and migration of hatchlings to the sea. 

Study results indicate that oil remaining on the beach approximately one year after a spill did not 

cause significant mortality in sea turtle eggs; however, fresh crude oil deposited on sand above a 

nest can cause extensive mortality to incubating sea turtle eggs (Fritts and McGehee, 1982). Fritz 

and McGehee (1982) noted that sea turtle eggs were damaged by contact with weathered oil 

released from the 1979 Ixtoc spill which oiled the Rancho Nuevo beaches in Mexico. In 1994, 

when beaches on St. Vincent NWR in the Florida panhandle became fouled with tar, female sea 

turtles crawled through the tar to lay nests, transferring the tar to the nest. However, no tar was 

found on the eggs in the nest. It has been proposed that olfactory clues are imprinted on 
54

hatchlings and guide them back to their natal beach for nesting when they reach maturity. Oil on 

the beach could interfere with these chemical guides (Lutz et al., 1985; Ogren, 1990; Possardt, 

1990). 

Oil collecting at beaches through which nesting adults or retreating hatchlings must pass can also 

affect the survivability of turtles in several ways. Damage can occur by toxic ingestion, with 

blockage of the digestive tract or internal and external inflammatory responses including infection 

and poisoning. Most impacts are believed to be sublethal, but little is known about the impacts of 

chronically ingested oil accumulating in organs. Studies have indicated that sea turtles do not 

seem to avoid oil slicks and may ingest or become fouled with the oil. There is concern that longterm chronic impacts would affect the survivability of turtles, both young and old. More 

definitive information is needed to assess the impacts of oiling on sea turtle nesting beaches. 

As delineated in OSRA, sea turtles’ nesting, mating, and general habitat extends to most of the 

Texas, Louisiana, Alabama, Mississippi, Florida coasts (Ji et al., 2002). According to OSRA, the 

highest estimated probability of an oil spill >1,000 bbl occurring and contacting sea turtle nesting 

habitats within 10 days is 3-4 percent (Ji et al., 2007) (Figure 4-20). Most GOM nesting habitat 

has an estimated probability of occurrence and contact of an oil spill >1,000 bbl within 30 days of 

1 percent or less. This represents a minimal threat to nesting adults or hatchling loggerhead, 

green, leatherback, and Kemp’s ridley sea turtles. In addition, MMS, USEPA, and USCG have 

regulations, requirements, and recommendations that are expected to prevent or reduce the 

likelihood of a spill occurring, and, if a spill occurs, prevent or reduce impacts to sea turtles. This 

and the weathering of oil in the environment are expected to significantly minimize potential 

impacts on sea turtles and their nesting habitat. 

The Finding of Affect for a proposed action on Kemp’s ridley and loggerhead sea turtles is Not 

Likely to Adversely Affect.

Alabama, Choctawhatchee, St. Andrew, and Perdido Key Beach Mice 

The proposed actions are not expected to have an impact on the Alabama (Peromyscus polionotus 

ammobates), Choctawhatchee (Peromyscus polionotus allophyrus), St. Andrew (Peromyscus 

polionotus peninsularius) and Perdido Key (Peromyscus polionotus trissyllepsis) beach mice 

because of the location of the proposed activities (100 mi offshore); the location of the primary 

and secondary onshore service bases (in Alabama, Mississippi, Louisiana, and Texas) are away 

from critical habitat; the low probability of an oil spill >1,000 bbl occurring and contacting their 

habitats within 10 days (<0.5%) (Figure 4-21); and the low probability of the species ingesting 

marine trash and debris. 

The Finding of Affect for a proposed action on the Alabama, Choctawhatchee, St. Andrew, and 

Perdido Key beach mice Not Likely to Adversely Affect; in addition, a proposed action is Not 

Likely to Adversely Modify Designated Critical Habitat for the Alabama, Choctawhatchee, and 

Perdido Key beach mice. 

Birds 

Four endangered or threatened birds were analyzed for potential effects in the EIS: piping plover, 

bald eagle, brown pelican, and whooping crane. Potential impact-producing factors for 

endangered or threatened birds include OCS-related helicopter and service-vessel traffic, air 

emissions, habitat degradation, trash and debris from service-vessels and OCS structures, oil 

spills, and spill-response activities. 

Piping Plover 
55

Potential impacts of particular concern regarding the piping plover (Charadrius melodus) would 

be from disturbance to its wintering habitat resulting from development of onshore facilities, 

aircraft and boat vessel traffic, and trash and debris (USDOI, FWS, 1989). Based on the National 

Park Service’s (NPS) marine debris study, it is also anticipated that impacts to wintering piping 

plovers from ingestion of, contact with, or entanglement in trash and debris would remain the 

same or decrease as a result of a proposed action. 

Low-altitude aircraft overflights related to OCS oil and gas operations could affect the wintering 

piping plover by temporary displacement. Birds startled by aircraft may leave and cease using 

their preferred feeding areas and possibly seek less-desirable ones. Rodgers and Smith (1997) 

found that shorebirds had the shortest flushing distances when disturbed by human activities 

(walking, all-terrain and other vehicles, and boats). Thus, piping plovers may be more 

susceptible to disturbance during foraging and loafing periods, resulting in increased energy 

expenditure via flight and alertness, and reduced energy intake via lower feeding rates. A 

minimum buffer of 100 m (328 ft) to minimize disturbance from walking, all-terrain vehicles, 

automobiles, and boats has been recommended (Rodgers and Smith, 1997). 

The FWS, FAA, NPS, and the U.S. Bureau of Land Management have an Interagency Agreement 

to reduce low-level flights over natural resource areas. The recommended minimum flight 

altitude is 2,000 ft above ground level. This limitation is included on aeronautical sectional maps. 

The FAA also encourages pilots to maintain higher-than-minimum altitudes over noise-sensitive 

areas. The MMS’s GOM OCS Region Office reminds lessees and operators that all aircraft, 

when used in support of their OCS oil and gas operations, must maintain altitudes of 2,000 ft or 

more when flying over all lands located within NWR’s, national parks, and seashores. If aircraft 

operators abide by the information provided on aeronautical maps and MMS’s recommended 

altitude over natural resource areas, impacts to piping plovers are expected to be minimal. 

Another potential source of impacts to the piping plover would be the fouling of wintering habitat 

from oil spills. The piping plover may be among the more vulnerable species because they forage 

in intertidal areas. Ingestion of oil could occur during the feeding process. Some oiling may 

occur through direct contact with oiled sediments or waves in the splash zone. The OSRA 

indicates that there is a 7-11 percent and a 16-26 percent probability piping plover wintering 

habitats in Texas, Louisiana, Mississippi, Alabama, and Florida would be impacted by an oil spill 

>1,000 bbl within 10 days from a WPA and CPA proposed action, respectively (Figure 4-22). It 

should be noted that the increase in probability since the 2002 OSRA models is not due to an 

increase in oil spills, but rather based on the expected increase in production. The amount of oil 

spilled has decreased. Oil spill prevention and response technology and mitigations have greatly 

improved and are expected to minimize the number of oil spills and the impact of spilled oil. 

The Finding of Affect for a proposed action on the wintering piping plover is Not Likely to 

Adversely Affect. In addition, a proposed action is Not Likely to Adversely Modify Designated 

Critical Habitat for the wintering piping plover. 

Bald Eagle 

Potential impacts of particular concern regarding the bald eagle (Haliaeetus leucocephalus) 

would be from OCS-related offshore, coastal, and inshore oil spills; OCS-related coastal and 

inshore spill-response activities, and disturbance from coastal and inshore transportation service 

operations. Most offshore activities are not a concern with respect to bald eagles since the birds 

do not forage that far offshore. 
56

Disturbance from helicopter or service-vessel traffic could sporadically disturb feeding, resting, 

or nesting bald eagles or cause abandonment of suitable habitats. Adherence of flight altitude 

restrictions by helicopter pilots and implementation of safe navigation practices by service-vessel 

captains is expected to significantly minimize the potential impacts to bald eagles from noise or 

collisions. Strict adherence to and enforcement of regulations regarding trash and debris disposal 

is also expected to minimize potential effects on bald eagles. 

Potential impacts to the eagle from an oil spill would be through direct contact of oil or 

contamination of its food source. It can be expected that bald eagles would be attracted to the 

area of a spill by dead and dying fish and birds to feed and thereby consume oil adhering to prey 

species or get oil on their feathers. Depending on the time of year, a decrease in the number of 

bald eagles at some or all life stages, could occur as a result of a spill. For offshore spills in 

deeper waters, with projected spill response, cleanup efforts, and natural weathering, most of the 

spill is expected to be recovered at the facility or before it reaches areas along the coast where the 

birds nest or feed. Spills in inshore waters are expected to originate near shore-base locations and 

are expected to affect a localized area but should be at a distance from bald eagle nests and 

foraging areas to not be a concern 

According to OSRA, there is a 1- 2 and an 18 - 29 percent chance of an oil spill >1,000 bbl 

occurring and contacting bald eagle coastal habitats within 10 days (Figure 4-25). If a spill were 

to occur, spill response, cleanup efforts, and natural weathering would result in most of a spill 

being recovered or dissipated. Oil-spill contingency plans as required by the Oil Pollution Act of 

1990 and MMS must address protection of sensitive species and habitats in the response plans. 

Any remaining oil or by-product is expected to affect a small area and dissipate rapidly. It should 

be noted that the increase in probability since the 2002 OSRA models is not due to an increase in 

oil spills, but rather based on the expected increase in production. The amount of oil spilled has 

decreased. Oil spill prevention and response technology and mitigations have greatly improved 

and are expected to minimize the number of oil spills and the impact of spilled oil. 

The Finding of Affect for a proposed action on the bald eagle is Not Likely to Adversely Affect. 

Brown Pelican 

Potential impacts of particular concern regarding the brown pelican (Pelicanus occidentalis) 

would be from air emissions, development of onshore facilities and infrastructure, associated 

aircraft and boat vessel traffic, and offshore oil- and gas-related trash and debris. 

Contamination of birds by air emissions can occur in two ways: absorption, and inhalation (the 

most common mode is inhalation). The major effects of air pollution include direct mortality, 

debilitating injury, disease, physiological stress, anemia, hypocalcemic condition, 

bioaccumulation of air pollutants with associated decrease in resistance to debilitating factors, 

and population declines (Newman, 1979). Levels of sulphur oxide (mainly SO2) emission from 

hydrocarbon combustion from OCS oil and gas activities is a concern in relation to birds. Due to 

their lack of tracheal submucosal glands, birds appear to have more tolerance for inhaled SO2

than most mammals (Llacuna et al., 1993; Okuyama et al., 1979). Direct and indirect effects 

include change in population distribution, food web contamination and habitat degradation, and 

synergistic effects with other natural and manmade stresses. Offshore operators are currently 

required by MMS to inventory their emissions. The total pollutant emissions per year are not 

uniform. During the early years of a proposed action, emissions would be small, increasing over 

time with full platform emplacements and production. After reaching a maximum during the 
57

development and production phase, emissions would decrease as all platforms and wells are 

removed. 

Major concerns related to helicopter and service-vessel traffic are intense aversion, panic, and 

injury or death following a bird's collision with a helicopter or vessel. Birds may also collide 

with ground structures after being frightened by a near miss with a helicopter or vessel. 

Disturbance from helicopter or service-vessel traffic could sporadically disturb feeding, resting, 

or nesting brown pelicans or cause abandonment of suitable habitat. Acclimation of birds to 

routine vessel traffic diminishes the effect. Adherence by helicopter pilots to flight altitude 

restrictions and safe navigation practices by service-vessel captains is expected to significantly 

minimize the potential impacts to brown pelicans from noise or collisions. 

Marine debris is particularly dangerous and often lethal to aquatic wildlife. Entanglement and 

ingestion of trash and debris would have the greatest impact on brown pelicans. Entanglement 

can result in the inability of birds to feed, care for their young, or fly. Results could include 

maiming and death. Ingesting debris can result in blocking the digestive pathways or remaining 

in the digestive system as inert material. Strict adherence to and enforcement of regulations 

regarding trash and debris is expected to also minimize potential effects on brown pelicans. 

Oil spills pose the greatest potential impact to coastal and marine birds such as brown pelican. 

Brown pelicans are active swimmers and plunge dive for prey. They are susceptible to both 

physical oiling and secondary effects via ingestion of oiled prey. If physical oiling of birds 

occurs, some degree of both acute and chronic physiological stress associated with direct and 

secondary uptake of oil would be expected. Ingestion of oils might reduce the function of the 

immune system and, thus, reduce resistance to infectious diseases (Leighton, 1990). Low levels 

of oil could stress birds by interfering with food detection, feeding impulses, predator avoidance, 

territory definition, susceptibility to physiological disorders, disease resistance, growth rates, 

reproduction, and respiration 

The probability of an oil spill occurring from a proposed action and contacting brown pelican 

habitat within 10 days is 8–13 and 10-16 percent for the WPA and the CPA, respectively (Figure 

4-24). The contact probabilities are considered conservative because they do not account for 

naturally occurring events such as weathering and activities included in a proposed action (e.g., 

clean up, containment, etc.). Thus, with projected spill response, cleanup efforts, and natural 

weathering, most of a spill would be recovered at the facility or before the oil reaches areas along 

the coast where the birds nest or feed. It should be noted that the increase in probability since the 

2002 OSRA models is not due to an increase in oil spills, but rather based on the expected 

increase in production. The amount of oil spilled has decreased. Oil spill prevention and response 

technology and mitigations have greatly improved and are expected to minimize the number of 

oil spills and the impact of spilled oil. 

The Finding of Affect for a proposed action on the brown pelican is Not Likely to Adversely 

Affect. 

Whooping Crane 

Potential impacts to the whooping crane (Grus americana) from proposed oil and gas activities 

are disturbance to its wintering habitats resulting from vessel and aircraft traffic, and trash and 

debris. Adherence by helicopter pilots to flight altitude restrictions and safe navigation practices 

by service-vessel captains is expected to significantly minimize the potential impacts from 

aircraft or vessel disturbance. The location of whooping crane wintering grounds on a protected 
58

wildlife refuge should offer further protection from disturbance. The MMS has issued NTL 

guidelines for handling of debris and for the elimination of accidental and unintentional release of 

trash or debris. Strict adherence to and enforcement of regulations from MMS and other agencies 

regarding trash and debris is expected to also minimize potential effects on whooping cranes. 

Oiled waters in whooping crane habitats could pose a considerable threat if an oil spill occurred 

when whooping cranes are on their wintering grounds in Texas (November to late April). 

Whooping cranes could be affected by ingestion of oil during feeding or by contact with oil in 

sediments or water. 

There is a <0.5 and 1 percent probability that an oil spill >1000 bbls would occur and contact 

whooping crane habitat within 10 days in the WPA and CPA, respectively (Figure 4-23). Though 

the wintering habitat is somewhat protected from oil spills by barrier islands, the loss of even a 

relatively small portion of the Texas population could be very significant. Oil spill prevention and 

mitigation regulations and guidelines by MMS and other agencies, and new technologies 

developed by industry to prevent oil spills and reduce spill impact, should minimize potential 

impacts on whooping cranes. 

The Finding of Affect for a proposed action on the whooping crane is Not Likely to Adversely 

Affect. 

Biological Assessment Conclusion 

The relevant federally protected species considered in this BA and the Finding of Affect for each 

are as follows: 

Birds 

The brown pelican, listed as endangered in Texas, Louisiana, and Mississippi, is Not Likely to be 

Adversely Affected by a proposed action. The bald eagle, listed as threatened in Texas, 

Louisiana, Mississippi, and Alabama, is Not Likely to be Adversely Affected by a proposed 

action. The piping plover, listed as threatened with critical habitat in Texas, Louisiana, 

Mississippi, and Alabama, is Not Likely to be Adversely Affected by a proposed action. The 

Whooping Crane, listed as endangered with critical habitat in Texas, is Not Likely to be 

Adversely Affected by a proposed action. 

Sea Turtles 

The loggerhead sea turtle, listed as threatened in Texas, Louisiana, Mississippi, and Alabama, is 

Not Likely to be Adversely Affected by a proposed action. The Kemp’s ridley, listed as 

endangered in Texas, is Not Likely to be Adversely Affected by a proposed action. 

Beach Mice 

The Alabama beach mouse, listed as endangered with critical habitat in Alabama, is Not Likely to 

be Adversely Affected by a proposed action. The Perdido beach mouse, listed as endangered 

with critical habitat in Alabama, is Not Likely to be Adversely Affected by a proposed action. 

As provided in 50 CFR 402.16, reinitiation of ESA Section 7 Consultation by MMS with FWS 

would occur if (1) new information reveals effects of a proposed action that may affect listed 

species or critical habitat in a manner or to an extent not considered in this opinion; (2) a 

proposed action is subsequently modified in a manner that causes an effect to the listed species or 
59

critical habitat designated that may be affected by the action; or (3) a new species is listed or 

critical habitat designated that may be affected by the action. 

 
ADDENDUM

Biological Assessment 

USFWS Consultation 

Gulf of Mexico OCS Oil and Gas 

Lease Sales: 2007-2012 
Coastal Spills 

In response to a request by the USFWS, this addendum to the Biological Assessment 

addresses coastal oil spill issues including physical characteristics, mitigation, regulation, 

and biological impacts. The greatest potential for an oil spill accident as a result of a 

proposed action occurs in offshore waters, usually at the site of industry development and 

production. MMS has published extensive data on the expected occurrence and the 

possible impacts of an offshore oil spill on a range of habitats, from oceanic waters to 

coastal beaches. However, the potential also exists for a spill to originate in the coastal 

waters as a result of a proposed action. Pipeline spills and barge spills are that two most 

likely sources of OCS-related spills that would occur in the coastal waters. 

In a recent review of spills across the nation, the USCG notes that most spills and spill 

volumes occurred in the Gulf of Mexico coastal waters (USCG, 2007). All types of crude 

oil and petroleum products cross the coastal areas of the Gulf of Mexico. Crude oil from 

the OCS is transported primarily by pipeline to shorebases and on to refineries. Imported 

foreign oil is transported by pipeline, barge and tanker. Bulk volumes of refined 

petroleum products which are also counted as oil spills are distributed for storage and sale 

along the Gulf coast, and lastly, fuel oils are lost from all sorts of vessels during 

consumer use. 

Coastal oil spills are of particular interest because of the presence of communities of 

coastal threatened and endangered species that could be impacted. The window of 

opportunity for response and naturally-occurring weathering is shorter than for offshore 

spills. 

Oil spills will occur in coastal waters as the result of the proposed action. The USCG 

maintains records of spills in coastal waters and State offshore waters, but the database 

does not identify whether the cause or source of the spill is related to OCS activities or 

not. In some cases, such as a pipeline that is carrying both State and OCS production 

from a shore base to a refinery, it is impossible to isolate the OCS spill. In the EIS 

process, MMS has used USCG records to quantify coastal spills likely to be the result of 

OCS activities by assuming that the proportion of spills is equivalent to the proportion of 

OCS oil. Since OCS oil is 19 percent of the total crude oil delivered to the Gulf coast 

states, 19 percent of the spills from OCS-type sources (MODUs, pipelines, etc) were 

assumed to be caused by OCS-related activity. 

Weathering 

The volume of oil spilled will be reduced by weathering. Weathering is dependent upon 

many factors, including water and air temperature, wind speed and the characteristics of 

the oil. The more rapidly the slick is transported to the shoreline, the less time is available 

for weathering. 

The spilled oil will spread out on the water surface, volatile components in the spill will 

evaporate to the atmosphere, water-soluble components will dissolve in water, and some 

droplets will physically disperse in the water column. The greatest volume of evaporation 
will occur within the first hours of the spill. The percent evaporative loss for a medium to 

light oil is 40 – 75 percent over several days (NRC, 2003). Transfer of VOCs to air would 

decrease exposure to aquatic organisms but result in an additional exposure pathway for 

coastal birds and turtles. Other less significant forms of weathering include emulsion 

formation, photo oxidation, biodegradation and sedimentation. 

Oil Spill Projections 

MMS discusses and projects coastal spills in the EIS: Section 4.1.2.4.4.6 and 4.1.3.4.4.7 

(pg 4-76 – 4-77), Section 4.3.1.3.2 ((pg 4-230), Table 4-13, Table 4-36, Table 4-37 and 

Table 4-38. 

An important point about Table 4-13 is that, if one considers it to contain 8 quadrants, 7 

of the 8 are a simple reporting of historical spill counts. All the projected coastal spills 

were determined from historic counts where the assumed size was obtained from 

Anderson and Labelle for the ≥1,000 bbl spills and by averaging the USCG dataset for 

<1000 bbl. 

In contrast, the estimate of OCS offshore spills > 1,000 bbl is obtained from detailed 

study of spills per BBO piped and sophisticated probabilistic analysis of factors by the 

MMS Resource Evaluation section. 

Source of data used in Table 4-13 

OCS source <1000 bbl ≥1,000 bbl 

 Off-shore USCG 

historical data 

1996 – 2001 

Anderson and LaBelle 

(2000) spill rates and 

EIS resource 

projections 

Coastal USCG 

historical data 

1996-2001 

USCG historical data 

1986 – 2001 

Non-OCS source 

 Off-shore USCG 

historical data 

1996-2001

USCG historical data 

1986 – 2001

Coastal USCG 

historical data 

1996-2001 

USCG historical data 

1986 – 2001 

• A recurring problem is that since the largest spills have 

occurred so rarely in recent history the projected number for 

the > 1,000 bbl spills comes out to be less than one. MMS 

wants to communicate that a spill greater than 1000 bbl is rare 

but possible and so the numbers are massaged so that the 

largest spill volume is retained and considered in the discussion 

as a possible future event. 
• For OCS-related coastal spills <1000 bbl: There were an 

average of 42 spills per year (1996-2001); eighty-five percent 

were from an unknown source but were counted as OCSrelated. 

• For OCS-related coastal spills ≥ 1000 bbl: In the USCG 

database, four spills ≥ 1000 bbl from OCS and non-OCS 

activities occurred in coastal waters during the 16 year period, 

1986 – 2001. One spill per six years was used in the table to 

show that a spill is possible. 

Table 4-36 and 4-37 provide a mass balance of spilled oil for in winter and summer. For 

coastal impacts, the column “Estimated Length of Shoreline Contact” is the most 

important column. In coastal waters, there would be less time elapsed for the slick to 

weather. Use of dispersants may not be permitted and there would be less time for 

mobilization for mechanical clean up. Therefore assuming dispersants were approved, a 

very rough estimate of the amount of shoreline contacted from a 4,600 bbl spill over a 

12-hour interval would be 50 km, the highest value in the two tables. However, additional 

modeling should be performed since this table was not directly designed to estimate 

shoreline contact. 

Table 4-38 provides the estimated number and assumed size of spills that could happen in 

coastal waters from an accident related to activities supporting the proposed action. Data 

from the year 2001 were used because it was the year with the most complete data. In 

2001, roughly 3 BBO arrived on the Gulf coast from state waters (<1 percent), OCS 

waters (19 percent) and foreign imports (81 percent). In 2001 there were a total of 270 

coastal spills of which 218 could have been from an OCS source. Included OCS sources 

were fixed platform, MODU, offshore marine facility, OSV, offshore pipeline, tank 

barge, tank ship, and unknown source. Twenty-two sources were not considered OCS 

sources. The elimination of categories such as recreational vessel or fishing vessel is 

straightforward but exclusion of other sources such as shoreline pipeline or unclassified 

vessel may be debated, and may be included in future analysis. 

A coastal spill rate of 74 spills per BBO was determined. Using the volume of oil 

projected for the CPA and WPA Multisale (Table 4-1), the total number of spills was 

determined. Spills were sorted into size category according to the distribution in the 

historical records. As mentioned previously, to avoid showing zero spills in the larger 

size categories, MMS did insert a value of one or more spills into Table 4-38 as needed. 

Coastal Spill Jurisdiction and Contingency Planning for Mitigation and Response 

Role/Responsibility/Jurisdiction
 The responsibilities delegated to MMS under the executive order for OPA 90, are closely 

related to spill prevention and spill response planning. These MMS responsibilities 

include spill prevention, review and approval of oil-spill response plans (OSRP’s), 

inspection of oil-spill containment and cleanup equipment, and ensuring oil-spill 

financial responsibility. MMS responsibilities also include ensuring that the operator of a 

facility carries out the training, equipment testing, and periodic drills described in the 

OSRP. The MMS regulations (30 CFR 254) require that all owners and operators of oil 

handling, storage, or transportation facilities located seaward of the coastline submit an 

OSRP for approval. 

MMS authority extends to facilities located seaward of the coastline. The term 

“coastline” means the line of ordinary low water along that portion of the coast which is 

in direct contact with the open sea and the line marking the seaward limit of inland 

waters. Facilities located inland of this line are subject to EPA, DOT, or USCG response 

plan requirements dependant upon the facility type and location. The term “facility” 

means any structure, group of structures, equipment, or device (other than a vessel), 

which is used for one or more of the following purposes: exploring for, drilling for, 

producing, storing, handling, transferring, processing, or transporting oil. A mobile 

offshore drilling unit is classified as a facility when engaged in drilling or downhole 

operations. 

The USCG’s responsibilities during a spill event is to ensure the effective and immediate 

removal or arrangement for removal of a discharge of oil or hazardous substance; 

mitigation or prevention of a substantial threat of a discharge of oil or hazardous 

substance; consultation with affected trustees; direction or monitoring of all federal, state, 

and private actions during a spill response; and removal completion determinations. 

Contingency Planning 

Oil-spill response planning in the United States is accomplished through a mandated set 

of interrelated plans. The ACP represents the third tier of the National Response 

Planning System and was mandated by OPA 90. The ACP’s cover subregional 

geographic areas. The ACP’s are a focal point of response planning, providing detailed 

information on response procedures, priorities, and appropriate countermeasures. 

Offshore response and cleanup is preferable to shoreline cleanup; however, if an oil slick 

reaches the coastline it is expected that the specific shoreline cleanup countermeasures 

identified and prioritized in the appropriate Area Contingency Plans (ACP’s) for various 

habitat types would be used. The MMS regulation at 30 CFR 254.2 requires that an 

OSRP must be submitted and approved before an operator can use a facility. As 

specified by OPA 90, the OSRP must be consistent with the National Contingency Plan 

and the Area Contingency Plan(s). 

The Gulf coastal area that falls within USCG District 8 is covered by the One Gulf Plan 

ACP, which includes separate Geographic Response Plans for areas covered by USCG 

Sector Corpus Christi, Sector Houston/Galveston, Sector Port Arthur, Sector Morgan 

City, Sector New Orleans, and Sector Mobile. The Miami ACP covers the remaining 

Gulf coastal area. The ACP’s are written and maintained by Area Committees assembled 
from Federal, State, and local governmental agencies that have pollution response 

authority; nongovernmental participants may attend meetings and provide input. 

Response procedures identified within an ACP or its Geographic Response Plan(s) reflect 

the priorities and procedures agreed to by members of the Area Committees. The 

sensitivity of the contaminated shoreline is generally the most important factor in the 

development of cleanup recommendations. 

 

The ACP’s applicable to the Gulf coastal area cover a vast geographical area. The 

differences in the response priorities and procedures among the various ACP’s or its 

Geographic Response Plans reflect the differences in the identified resources needing 

spill protection in the area covered by each ACP or its Geographic Response Plans. In 

the event of an actual spill, the ACP applicable to the potentially impacted area would be 

utilized by the responsible party. 

Spill Response 

The single most frequently recommended spill-response strategy for the areas identified 

for protection in all of the applicable ACP’s or it’s Geographic Response Plans is the use 

of a shoreline boom to deflect oil away from coastal resources such as seagrass beds, 

marinas, resting areas for migratory birds, bird and turtle nesting areas, etc. If a shoreline 

is oiled, the selection of the type of shoreline remediation to be used will depend on the 

following: (1) the type and amount of oil on the shore; (2) the nature of the affected 

coastline; (3) the depth of oil penetration into the sediments; (4) the accessibility and the 

ability of vehicles to travel along the shoreline; (5) the possible ecological damage of the 

treatment to the shoreline environment; (6) weather conditions; and (7) the current state 

of the oil. 

Mechanical response would be the preferred response to attempt to prevent oil from 

reaching shoreline areas. The USCG’s direction or monitoring of all federal, state, and 

private actions during a spill response will include consultation with affected trustees 

regarding the selection of appropriate spill response techniques and prioritization of 

potentially impacted resources during a spill response. Dispersant use and/or insitu 

burning in near shore areas would only be conducted if approval was granted by the 

Federal On-Scene Coordinator, usually the USCG Captain of the Port, in consultation 

with the State and affected federal agencies, pursuant to the National Contingency Plan 

Biological Issues

With the de-listing of the Bald Eagle on August 8, 2007, this informal consultation now 

includes seven species, including the brown pelican, the piping plover, the whooping 

crane, the Alabama beach mouse, the Perdido Key beach mouse, the loggerhead sea turtle 

and the Kemp’s ridley sea turtle. Coastal oil spills from any source, under specific 

conditions, could result in severe impacts to any of these listed species. However, the 

potential of impact of a coastal spill from a proposed action is reduced for some species 

by location (both species of beach mouse) or by seasonal absence from the proposed 

action area (piping plover, whooping crane, loggerhead sea turtle and Kemp’s ridley sea 

turtle). 
Brown pelican 

The only species with a year-round presence in the proposed action area is the brown 

pelican. These birds are found in coastal areas of each of the central and western Gulf 

coast states. Because of the year-round presence, this may be the species most vulnerable 

to coastal oil spills, and press coverage of oiled pelican clean-up has been a very visible 

reminder of past oil spills (most of which are not OCS-related). Pelicans do not generally 

occur in large groups and the small size of typical coastal spills associated with a 

proposed action would not be expected to impact more than several individuals. Past spill 

response experience in recovering pelicans and the location on the Gulf coast of state-ofthe-art pelican response crews and facilities further reduces the potential impact of OCSrelated coastal spills. 

Breeding colonies are the major exception to the typically more dispersed brown pelican 

population. Pelicans migrate to breeding colonies from all along the coast, finding safety 

in numbers for nesting activities. The major colony at Breton Island off the Louisiana 

coast had 2000 nests in 2007. This was particularly noteworthy since Breton was severely 

impacted by Hurricane Katrina in 2005. Pelican egg laying peaks in March and April and 

eggs hatch a month later. Young pelicans fly at about 75 days. This time period 

represents the highest potential for impact from a coastal oil spill as so many pelicans are 

present in a small geographic area. Though the 5-month window and compact area reduce 

the probability of OCS-related spill impact, should one occur, it could affect many birds. 

Fortunately, the number of estimated spills >1bbl are few (Table 4-38). MMS does not 

expect coastal OCS-related oil spills to jeopardize the Gulf Coast brown pelican 

population, which appears to be maintaining sustained growth. 

Piping plover 

Piping plover are not present on the Gulf coast year-round (usually) but overwinter and 

have designated critical habitat in all five Gulf coastal states. Plover begin arriving on the 

Gulf coast in mid-July, though arrivals increase through October. Northern migration 

begins in late February and most of the plovers are gone by May. Thus, for about 30 

percent of the year, piping plover are not present on the coast and not susceptible to 

coastal oil spill impacts. When the plovers are present, an OCS-related coastal spill could 

impact the birds and their critical habitat. However, piping plover are not expected to be 

adversely affected due to the small numbers and size of estimated coastal spills and the 

mitigations to minimize impact. Preliminary findings of the 2006 International Census 

indicate that overall winter numbers were very high with particularly high bird counts in 

Texas. 

Whooping crane 

Although the numbers of whooping cranes in the Aransas National Wildlife Refuge 

population have greatly increased from 57 in winter 2002-03 to 237 in winter 2006-07, 

this fragile population could be severely impacted from a coastal oil spill. The loss of 

only a few individuals of such a small group could have major implications. Since this 

population also represents the majority of the world’s free-ranging whooping cranes, 

avoidance of any disturbance is even more important. Coastal oil spills from OCS-related 
proposed actions are not expected to adversely affect the Aransas whooping cranes for 

two primary reasons: 1) the birds are only present on the Gulf coast for approximately 

half of the year, and 2) the Aransas National Wildlife Refuge and surrounding essential 

habitat for the whooping cranes is not in an area of high probability for coastal oil spills. 

Since pipeline accidents are by far the greatest potential for OCS-related coastal oil spills, 

the areas of highest pipeline concentration (Galveston area in Texas and the Plaquemines 

Parish area in Louisiana) are the areas of highest probability for a coastal spill. 

Alabama and Perdido Key beach mice 

The threat of impact to beach mice from a coastal spill resulting from a proposed action is 

discountable. There are no operations, including pipelines or oil transport, scheduled to 

occur Alabama or Florida coastal waters, where beach mice and their critical habitat are 

located. 

Loggerhead sea turtle 

For the purposes of this FWS consultation, periods of potential impact are restricted to 

the nesting season, which occurs from late April to early September, and the hatching 

season lasting from late June to mid-November. Thus, loggerhead sea turtles are only 

subject to possible coastal oil spill effects for approximately 60 percent of the year. Gulf 

coast loggerhead nests are primarily located in the Florida panhandle, though nesting has 

been reported in other Gulf coast states. As there is no oil transport or other operations 

expected in Florida or Alabama waters from a proposed action, there is negligible 

potential for impact from coastal oil spills to nesting turtles or hatchlings on Florida or 

Alabama beaches. There has been no loggerhead nests recorded in Louisiana in the last 

five years. Texas reported two loggerhead nests in 2006 and three so far in 2007. 

Although numbers for Mississippi were not available, numbers of nests in that state are 

expected to be very low. With a nesting and hatching season of less than seven months a 

year, extremely rare nesting occurrences, and low estimated numbers and volumes of oil 

spilled in coastal waters from a proposed actions, MMS believes that the potential impact 

to nesting or hatchling loggerheads is discountable. 

Kemp’s ridley 

As the most endangered sea turtle, Kemp’s ridley nests were historically confined to 

Rancho Nuevo in Mexico. Efforts in the last few decades to relocate nests and imprint 

hatchlings to the beach at South Padre Island, Texas, as well as mitigate turtle deaths in 

shrimp trawls, are showing signs of success. So far in 2007, 125 Kemp’s ridley nests 

have been counted on South Padre Island which is the highest number since recording 

began in the 1980’s. Fifteen nests were found in the Galveston County area, which is also 

the highest count for that area. 

MMS believes that coastal oil spills as a result of proposed actions are not likely to 

adversely affect Kemp’s ridley nesting and hatchling sea turtles for several reasons: 1) 

the nesting season on the Texas coast for Kemp’s ridley sea turtles is early April through 

mid-June. This means that the nesting turtles would only be subject to coastal oil spill 

impact for approximately 20 percent of the year; 2) the South Padre Island area is not in 

the area of highest pipeline placements and the subsequent highest probability for a 
coastal oil spill (Galveston area); 3) nests and hatchlings on South Padre Island are 

closely monitored and hatchlings are generally protected from impact as they leave the 

nest and crawl to the ocean; 4) nesters and hatchlings on Galveston beaches are in the 

area with higher coastal oil spill probabilities. However, the females are only on the 

beach long enough to nest and recent observer program developments have resulted in 

the eggs being removed from the nest for hatching elsewhere. Thus, the eggs and 

hatchlings are not potentially subject to coastal oil spill affects. Even in the areas of 

higher pipeline concentration, oil spills >1bbl are expected to occur rarely. 
Appendix C 

Attachment 3 

MMS Concurrence Letter 














Appendix C 

Attachment 4 

FWS Correspondence Re: Supplemental EIS 


Appendix C 

Attachment 5 

NMFS Concurrence Letter 


Appendix C 

Attachment 6 

BOEM Email on Reinitiated Consultation
From: Epperson, Deborah [mailto:Deborah.Epperson@boem.gov] 

Sent: Wednesday, May 09, 2012 12:22 PM 

To: Donald Evans 

Cc: Ensz, Holli 

Subject: RE: NMFS Biological Opinion for GOM 

Don,

As we discussed, the current consultation with NMFS was reinitiated following the DWH event and we are

working with NMFS on a new consultation that I am hoping will be completed by the end of this 

year. There were no new species or critical habitats identified and we are still consulting with NMFS on 

sperm whales, all 5 species of sea turtles, and the gulf sturgeon.

 

Please let me know if you need more information.

Deborah 

 

From: Donald Evans [mailto:DOEV@statoil.com] 

Sent: Wednesday, May 09, 2012 11:44 AM 

To: Epperson, Deborah 

Subject: NMFS Biological Opinion for GOM

Deborah, 

Thanks for your time this morning discussing the current NMFS biological opinion and the new 

consultation for the GOM which is currently open and covers all three planning areas (western, central

and eastern). No new endangered species have been included in the new consultation and air quality 

impacts are not expected to adversely impact any threatened or endangered species or critical habitats. 

Thanks again, 

Donald P. Evans 

Lead HSE - Environmental 

Statoil – DPNA UON HSE 

t: 713 485 2203 

m: 832 788 9282 

e: doev@statoil.com

2103 CityWest Blvd 

Suite 800 

Houston, TX 77042 
USA 

www.statoil.com

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