Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas Activities in the Gulf of Mexico

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 GOM 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. The rule became effective on April 19, 2021.

Our 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” (LPAI) standard of the MMPA.

NMFS issued a LOA to Murphy on March 20, 2024, for the take of marine mammals incidental to a three-dimensional (3D) ocean bottom node survey in the Green Canyon protraction areas, including approximately 44 lease blocks, effective April 1, 2024, through October 31, 2024. Please see the Federal Register notice of issuance (89 FR 20946, March 26, 2024) for additional detail regarding the LOA and the survey activity.

Murphy has requested that the October 31, 2024, expiration date be extended to January 31, 2025, due to survey delays (the survey has not begun). Since we issued the LOA to Murphy, we have updated the final rule to include corrected take estimates and new information as discussed above; therefore, we have updated the authorized take numbers accordingly based on this new information. There are no changes to the planned survey, as described in the previous notice of issuance (89 FR 20946, March 26, 2024), including the planned location and duration of the survey.

As discussed in the previous notice of issuance (89 FR 20946, March 26, 2024), no 3D OBN surveys were included in the modeled survey types, thus the coil proxy was selected. Murphy plans to cover approximately 25.6 square kilometers (km² ) per day compared to the 144 km² in the coil proxy, and although Murphy is not proposing to perform a survey using the coil geometry, the coil proxy is most representative of the effort planned by Murphy in terms of predicted Level B harassment exposures. Additionally, Murphy plans to use a 28-element, 5,230 cubic inch (in³ ) airgun array and therefore the 5,110 in³ proxy was selected.

The survey will take place over approximately 44 days with 40 days of sound source operation, all planned in Zone 5. The monthly distribution of survey days is not known in advance, though we assume that the planned 40 days of source operation would occur contiguously. Take estimates for each species are based on the time period that produces the greatest value. There are no other changes to Murphy's planned activity.

For the Rice's whale, take estimates based solely on the modeling yielded results that are not realistically likely to occur when considered in light of other relevant information available during the rulemaking process regarding marine mammal occurrence in the GOM. The approach used in the acoustic exposure modeling, in which seven modeling zones were defined over the U.S. GOM, necessarily averages fine-scale information about marine mammal distribution over the large area of each modeling zone. Thus, although the modeling conducted for the rule is a natural starting point for estimating take, the rule acknowledged that other information could be considered (see, e.g.,86 FR 5442, January 19, 2021, discussing the need to provide flexibility and make efficient use of previous public and agency review of other information and identifying that additional public review is not necessary unless the model or inputs used differ substantively from those that were previously reviewed by NMFS and the public). For this survey, NMFS has other relevant information reviewed during the rulemaking that indicates use of the acoustic exposure modeling to generate a take estimate may produce results inconsistent with what is known regarding their occurrence in the GOM. Accordingly, we have adjusted the calculated take estimates as described below.

NMFS' 2024 final rule provided detailed discussion regarding Rice's whale habitat (see, e.g.,89 FR 31508, 31519). In summary, recent survey data, sightings, and acoustic data support Rice's whale occurrence in waters throughout the GOM between approximately 100 m and 400 m depth along the continental shelf break, and associated habitat-based density modeling has identified similar habitat ( i.e., approximately 100 to 400 m water depths along the continental shelf break) as being Rice's whale habitat (Garrison et al., 2023; Soldevilla et al., 2022, 2024).

Although Rice's whales may occur outside of the general depth range expected to provide suitable habitat, we expect that any such occurrence would be rare. Murphy's planned activities will occur in water depths of approximately 914 to 3,372 m in the central GOM. Thus, NMFS does not expect there to be the reasonable potential for take of Rice's whale in association with this survey and, accordingly, does not authorize take of Rice's whale through the LOA.

Based on the results of our analysis, NMFS has determined that the level of taking expected for this survey and authorized through the LOA is consistent with the findings made for the total taking allowable under the regulations. See table 1 in this notice and table 6 of the rule (89 FR 31488, April 24, 2024).

Small Numbers Determination

Under the GOM rule, NMFS may not authorize incidental take of marine mammals in an LOA if it will exceed “small numbers.” In short, when an acceptable estimate of the individual marine mammals taken is available, if the estimated number of individual animals taken is up to, but not greater than, one-third of the best available abundance estimate, NMFS will determine that the numbers of marine mammals taken of a species or stock are small (see 89 FR 31535, May 24, 2024). For more information please see NMFS' discussion of small numbers in the 2021 final rule (86 FR 5438, January 19, 2021).

The take numbers for authorization are determined as described above. Subsequently, the total incidents of harassment for each species are multiplied by scalar ratios to produce a derived product that better reflects the number of individuals likely to be taken within a survey (as compared to the total number of instances of take), accounting for the likelihood that some individual marine mammals may be taken on more than 1 day (see 86 FR 5404, January 19, 2021). The output of this scaling, where appropriate, is incorporated into adjusted total take estimates that are the basis for NMFS' small numbers determinations, as depicted in table 1.

This product is used by NMFS in making the necessary small numbers determinations through comparison with the best available abundance estimates (see discussion at 86 FR 5391, January 19, 2021). For this comparison, NMFS' approach is to use the maximum theoretical population, determined through review of current stock assessment reports (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments ) and model-predicted abundance information ( https://seamap.env.duke.edu/models/Duke/GOM/ ). Information supporting the small numbers determinations is provided in table 1.