# Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas Activities in the Gulf of America (Formerly Gulf of Mexico)
**AGENCY:**
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
**ACTION:**
Notice; issuance of letter of authorization.
**SUMMARY:**
In accordance with the Marine Mammal Protection Act (MMPA), as amended, its implementing regulations, and NMFS' MMPA regulations for taking marine mammals incidental to geophysical surveys related to oil and gas activities in the Gulf of America, originally published as “Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas Activities in the Gulf of Mexico,” notification is hereby given that NMFS has issued a revised Letter of Authorization (LOA) to WesternGeco LLC (WesternGeco), in place of Viridien, for the take of marine mammals incidental to geophysical survey activity in the Gulf of America (GOA).
**DATES:**
The LOA is effective through April 19, 2026.
**ADDRESSES:**
The LOA, LOA request, and supporting documentation are available online at: *https://www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-america.* In case of problems accessing these documents, please call the contact listed below (see *FOR FURTHER INFORMATION CONTACT* ).
**FOR FURTHER INFORMATION CONTACT:**
Jenna Harlacher, Office of Protected Resources, NMFS, (301) 427-8401.
**SUPPLEMENTARY INFORMATION:**
**Background**
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 *et seq.* ) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.
An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. NMFS has defined “negligible impact” in 50 CFR 216.103 as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.
Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as: any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).
On January 19, 2021, we issued a final rule with regulations to govern the unintentional taking of marine mammals incidental to geophysical survey activities conducted by oil and gas industry operators, and those persons authorized to conduct activities on their behalf (collectively “industry operators”), in U.S. waters of the GOA [^1] over the course of 5 years (86 FR 5322, January 19, 2021). The rule was based on our findings that the total taking from the specified activities over the 5-year period will have a negligible impact on the affected species or stock(s) of marine mammals and will not have an unmitigable adverse impact on the availability of those species or stocks for subsistence uses, and became effective on April 19, 2021.
[^1] Pursuant to Executive Order 14172, “Restoring Names That Honor American Greatness,” and Department of the Interior Secretarial Order 3423, “The Gulf of America,” the body of water formerly known as the Gulf of Mexico is now called the Gulf of America. Accordingly, NMFS amended the incidental take regulations to reflect the change. See 90 FR 38001 (August 7, 2025).
The regulations at 50 CFR 217.180 *et seq.* allow for the issuance of LOAs to industry operators for the incidental take of marine mammals during geophysical survey activities and prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species or stocks and their habitat (often referred to as mitigation), as well as requirements pertaining to the monitoring and reporting of such taking. Under 50 CFR 217.186(e), issuance of an LOA shall be based on a determination that the level of taking will be consistent with the findings made for the total taking allowable under these regulations and a determination that the amount of take authorized under the LOA is of no more than small numbers.
NMFS subsequently discovered that the 2021 rule was based on erroneous take estimates. We conducted another rulemaking using correct take estimates and other newly available and pertinent information relevant to the analyses supporting some of the findings in the 2021 final rule and the taking allowable under the regulations. We issued a final rule in April 2024, effective May 24, 2024 (89 FR 31488, April 24, 2024).
The 2024 final rule made no changes to the specified activities or the specified geographical region in which those activities would be conducted, nor to the original 5-year period of effectiveness. In consideration of the new information, the 2024 rule presented new analyses supporting affirmance of the negligible impact determinations for all species, and affirmed that the existing regulations, which contain mitigation, monitoring, and reporting requirements, are consistent with the “least practicable adverse impact” standard of the MMPA.
**Summary of Request and Analysis**
On August 1, 2025, NMFS issued an LOA to Viridien (90 FR 37842, August 6, 2025) to take marine mammals incidental to a three-dimensional (3D) ocean bottom node (OBN) survey over 2,023 lease blocks in the Garden Banks, Keathley Canyon, East Breaks, and Alaminos Canyon areas, with water depths ranging from approximately 185 to 2,095 meters (m). See section F of the LOA application for a map of the area. Additional description of the planned survey, as well as analysis related to the issuance of that LOA, is available in Viridien's LOA application and the aforementioned *Federal Register* notice of issuance.
On December 9, 2025, Viridien requested the transfer of the LOA to its partner in the planned survey effort (WesternGeco). WesternGeco confirmed to NMFS that it similarly requested transfer of the LOA. With the transfer of the LOA, WesternGeco agrees to comply with the associated terms, conditions, stipulations, and restrictions of the original LOA. No other changes were requested. The revised LOA remains effective through April 19, 2026.
The revised LOA sets forth only a change in the LOA holder. There are no other changes to the LOA as described in the August 6, 2025, *Federal Register* notice of issuance (90 FR 37842): the specified activity; estimated take by incidental harassment; and small numbers analysis and determination; and the period of effectiveness remain unchanged and are herein incorporated by reference.
**Authorization**
NMFS has determined that the level of taking for this LOA request is consistent with the findings made for the total taking allowable under the incidental take regulations and that the amount of take authorized under the LOA is of no more than small numbers. Accordingly, we have issued an LOA to WesternGeco authorizing the take of marine mammals incidental to its geophysical survey activity, as described above.
Dated: December 19, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries Service.