The National Marine Fisheries Service (NMFS), an agency under the National Oceanic and Atmospheric Administration (NOAA) within the Department of Commerce, has issued six Letters of Authorization (LOAs) to various oil and gas industry operators, permitting the incidental take of marine mammals. These authorizations enable companies including WesternGeco, TGS, Future Energy Consultants (FEC), bp Exploration & Production Inc. (bp), Viridien, and LLOG Exploration Offshore, L.L.C. to conduct geophysical survey activities in the Gulf of America. The LOAs, which have staggered effective dates through early 2031 for some operators, signify the continuation of a federal regulatory framework aimed at balancing critical energy exploration with the protection of marine mammal populations under the Marine MammA Protection Act (MMPA).
The Marine Mammal Protection Act Framework
The MMPA (16 U.S.C. 1361 et seq.) mandates that the Secretary of Commerce allow the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens engaged in specific activities, provided certain findings are made. Key among these findings is that the taking will have a "negligible impact" on the species or stock and will not have an "unmitigable adverse impact" on their availability for subsistence uses. NMFS defines "negligible impact" as an impact not reasonably expected to adversely affect a species or stock through effects on annual rates of recruitment or survival. "Harassment" is broadly defined to include any act with the potential to injure (Level A harassment) or disturb behavioral patterns (Level B harassment) of a marine mammal. This regulatory structure is critical for industrial activities that involve underwater sound, such as geophysical surveys, which can produce acoustic impacts on marine life.
Evolution of Incidental Take Regulations in the Gulf of America
The current issuance of LOAs follows a complex regulatory history. NMFS initially issued a final rule on January 19, 2021, effective April 19, 2021, to govern the unintentional taking of marine mammals incidental to geophysical survey activities in the U.S. waters of what is now known as the Gulf of America. The name change from Gulf of Mexico to Gulf of America was enacted through Executive Order 14172, "Restoring Names That Honor American Greatness," and Department of the Interior Secretarial Order 3423, both attributed to President Trump.
However, NMFS later discovered that the 2021 rule was based on "erroneous take estimates." This prompted a subsequent rulemaking process, culminating in a new final rule issued in April 2024, which became effective on May 24, 2024. To prevent a lapse in incidental take coverage, especially as the 2021 ITR approached its expiration, NMFS's Office of Protected Resources received a request from its Office of Policy in August 2025 for reimplementation. The Bureau of Ocean Energy Management (BOEM), the original petitioner, joined as a co-petitioner. This led to a new final rule, effective April 20, 2026, through April 19, 2031, which continues the established framework for issuing LOAs without altering the specified activities, geographical region, or associated mitigation, monitoring, and reporting requirements.
Current Authorizations and Survey Specifics
The recently issued LOAs detail the specific activities and timeframes for each company. WesternGeco's LOA, effective April 20, 2026, through August 31, 2026, allows for a three-dimensional (3D) ocean bottom node (OBN) survey over 200 lease blocks in the Green Canyon and Walker Ridge areas. Their operations involve conventional airgun arrays and, in some cases, a low-frequency tuned pulse source (TPS). NMFS previously reviewed the TPS as a "new and unusual technology" and determined its effects would not exceed those considered in traditional airgun array modeling.
TGS received an LOA effective April 20, 2026, through May 31, 2026, to conduct a 3D OBN survey over 453 lease blocks in the East Breaks area. TGS anticipates using two source vessels with a low-frequency airgun source known as Gemini, also deemed a "new and unusual technology" by NMFS but not expected to cause effects beyond those modeled for traditional airguns. Both WesternGeco and TGS had previous LOAs under the 2021 ITR that required reissuance or modification due to survey changes and the expiration of the prior regulatory period.
Future Energy Consultants (FEC) will conduct a FloatSeis seismic field trial survey in lease block LA5A, utilizing both 2,450 cubic inch and 220 cubic inch airgun arrays. Other companies, bp, Viridien, and LLOG, also received LOAs with varying effective dates, with LLOG's extending until April 19, 2031, indicating longer-term operational plans. All authorizations are contingent upon adherence to specified mitigation, monitoring, and reporting requirements designed to ensure the least practicable adverse impact on marine mammals.
Regulatory Safeguards and Ongoing Oversight
Under the regulations, the issuance of an LOA is predicated on a determination that the level of incidental take will be consistent with the total taking allowable under the broader regulations, and that the amount authorized represents "small numbers" of takes. These determinations are made based on acoustic exposure modeling and updated survey plans. The continuous oversight and revision of these regulations by NMFS underscore the ongoing commitment to adapt to new scientific information and operational realities, such as the need to correct erroneous take estimates and ensure uninterrupted regulatory coverage for industry activities.
