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Department of Commerce National Oceanic and Atmospheric Administration
50 CFR Part 217 [Docket No. 241018-0276] RIN 0648-BM30 AGENCY:
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION:
Proposed rule; request for comments.
SUMMARY:
NMFS received a request from the Don Young Port of Alaska (POA) for authorization to take marine mammals incidental to the Cargo Terminals Replacement Project at the existing port facility in Anchorage, Alaska over the course of 5 construction seasons (2026 through 2030). Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is proposing regulations setting forth permissible methods of taking, other means of effecting the least practicable adverse impact on such marine mammal stocks ( i.e., mitigation measures), and requirements pertaining to monitoring and reporting such takes and requests comments on the proposed regulations. NMFS will consider public comments prior to making any final decision on the promulgation of the requested MMPA regulations, and NMFS's responses to public comments will be summarized in the final notification of our decision.
DATES:
Comments and information must be received no later than November 27, 2024.
ADDRESSES:
A plain language summary of this proposed rule is available at https://www.regulations.gov/docket/NOAA-NMFS-2024-0030 . You may submit comments on this document, identified by NOAA-NMFS-2024-0030, by the following method:
- Electronic Submission: Submit all electronic public comments via the Federal e-Rulemaking Portal. Visit https://www.regulations.gov and type NOAA-NMFS-2024-0030 in the Search box. Click on the “Comment” icon, complete the required fields, and enter or attach your comments.
Instructions: Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on https://www.regulations.gov without change. All personal identifying information ( e.g., name, address, etc.), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous).
Electronic copies of the application and supporting documents, as well as a list of the references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization. In case of problems accessing these documents, please call the contact listed below.
FOR FURTHER INFORMATION CONTACT:
Cara Hotchkin, Office of Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, promulgated under the authority of the MMPA (16 U.S.C. 1361 et seq.), would provide a framework for authorizing the take of marine mammals incidental to construction activities associated with the POA's Modernization Program, including impact and vibratory pile driving.
NMFS received an application from the POA requesting 5-year regulations and a letter of authorization issued thereunder to take individuals of seven species, comprising nine stocks of marine mammals by Level A harassment and Level B harassment incidental to the POA's activities. No serious injury or mortality is anticipated or proposed for authorization. Please see Background below for definitions of harassment.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs 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 for up to 5 years if, after notice and public comment, the agency makes certain findings and promulgates regulations that set forth permissible methods of taking pursuant to that activity and other means of effecting the “least practicable adverse impact” on the affected species or stocks and their habitat (see the discussion below in the Proposed Mitigation section), as well as monitoring and reporting requirements. Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I provide the legal basis for issuing this proposed rule containing 5-year regulations and for any subsequent Letters of Authorization (LOAs).
Summary of Major Provisions Within the Proposed Rule
Following is a summary of the major provisions of this proposed rule regarding POA's activities. These measures include:
- Prescribing permissible methods of taking of small numbers of marine mammals by Level A harassment and/or Level B harassment incidental to the Cargo Terminals Replacement Project;
- Required monitoring of the construction areas to detect the presence of marine mammals before beginning construction activities;
- Establishment of shutdown zones equivalent to the estimated Level B harassment zone for beluga whales;
- Establishment of shutdown zones equivalent to or greater than the estimated Level A harassment zones for other species;
- Bubble curtains required for all impact and vibratory driving of permanent (72-inch (in) (1.83 meter (m))) piles in more than 3 m of water depth in all months and for vibratory driving of all temporary (24-in (0.61 m) or 36-in (0.91 m)) and permanent (72-in) piles between August and October;
- Soft start for impact pile driving to allow marine mammals the opportunity to leave the area prior to beginning impact pile driving at full power; and
- Submittal of monitoring reports including a summary of marine mammal species and behavioral observations, construction shutdowns or delays, and construction work completed.
Through adaptive management, the proposed regulations would allow NMFS Office of Protected Resources to modify ( e.g., remove, revise, or add to) the existing mitigation, monitoring, or reporting measures summarized above and required by the LOA.
Background
The MMPA prohibits the “take” of marine mammals, with certain exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) 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 promulgated or an incidental harassment authorization is issued.
Authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s) and will not have an unmitigable adverse impact on the availability of the species or stock(s) for taking for subsistence uses (where relevant). If such findings are made, NMFS must prescribe the permissible methods of taking and other “means of effecting the least practicable adverse impact” on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stocks for taking for certain subsistence uses (referred to in shorthand as “mitigation”); and requirements pertaining to the monitoring and reporting of the takings are set forth. The definitions of all applicable MMPA statutory terms cited above are included in the relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, NMFS must evaluate our proposed action's ( i.e., promulgation of regulations and subsequent issuance of a LOA thereunder) and alternatives to that action's potential impacts on the human environment.
Accordingly, NMFS has prepared an Environmental Assessment (EA) to evaluate the environmental impacts associated with the issuance of the proposed regulations and LOA. NMFS' EA is available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization. We will review all comments submitted in response to this notice prior to concluding our NEPA process or making a final decision on this request.
Summary of Request
On January 3, 2023, NMFS received a request from the POA for regulations and a subsequent LOA to take marine mammals incidental to construction activities related to the POA Modernization Program (PAMP) Phase 2B: Cargo Terminals Replacement (CTR) at the POA in Anchorage, Alaska. NMFS provided comments on the application on March 3, 2023, April 20, 2023, and May 18, 2023. After POA submitted a revised application on October 13, 2023, and responded to additional questions sent on December 20, 2023, we determined the application was adequate and complete on February 12, 2024.
On March 4, 2024, we published a notice of receipt (NOR) of application in the Federal Register (89 FR 15548), requesting comments and information during a 30-day public comment period related to the POA's request. We received one comment letter from the Center for Biological Diversity. NMFS has reviewed all submitted material and taken the information into consideration during the drafting of this proposed rule.
The POA's request is for take of seven species of marine mammals by Level B harassment and for a subset of these species, Level A harassment. Neither POA nor NMFS expect serious injury or mortality to result from the specified activities. If promulgated, the regulations would be effective for the first 5 construction seasons (2026-2030).
NMFS previously issued IHAs to the POA for similar work (85 FR 19294, April 6, 2020; 86 FR 50057, September 7, 2021; 89 FR 2832, January 14, 2024). The POA complied with all the requirements ( e.g., mitigation, monitoring, and reporting) of the previous IHAs and information regarding their monitoring results may be found in the Effects of the Specified Activity on Marine Mammals and their Habitat and Estimated Take of Marine Mammals sections of this proposed rule and online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
Description of the Specified Activities
Overview
The POA, located on Knik Arm in upper Cook Inlet, provides critical infrastructure for the citizens of Anchorage and a majority of the citizens of Alaska. The POA was constructed primarily in the 1960s and is currently in poor condition and substantially past its initial design life. The existing cargo terminals T1, T2, and T3 are deteriorating and in poor structural condition and present safety and security concerns for human health and the economic stability of the state of Alaska. The PAMP is designed to replace the existing facilities with new infrastructure incorporating modern seismic codes over a 75-year design life. PAMP Phase 2B includes the demolition and replacement of terminals T1 and T2 and the partial demolition of T3. This phase is expected to take approximately 6 years of in-water work to complete. If promulgated, the regulations would be effective for the first 5 construction seasons (2026-2030).
In-water pile installation will include both temporary (24-in (0.61 m) or 36-in (0.91 m)) and permanent (72-in (1.83 m)) steel pipe piles by impact and vibratory hammers. Removal of temporary piles (24- or 35-in) and existing structures (16-in (0.41 m) to 42-in (1.07 m) steel pipe piles) would be primarily by cutting; dead-pull and vibratory extraction methods may also be used. Existing piles may also be left standing in their current positions. In-water work associated with the project would include installation of approximately 275 permanent piles and 450 temporary piles and vibratory extraction of approximately 46 temporary piles over the 5-year period.
Dates and Duration
The POA anticipates that in-water construction activities associated with this proposed rule would begin on April 1, 2026 and extend through November 30, 2030. In-water pile installation and removal associated with the CTR project is anticipated to take place over approximately 689 hours on approximately 337 nonconsecutive days between the months of April and November over the 5 year period (see table 1 for estimated production rates and durations). While the exact sequence of demolition and construction is uncertain, an estimated schedule is shown in table 2. This schedule is based on best available information and is not intended to be a limitation on the number of pile installation or removal hours that may occur in any given month.
The POA has presented the schedule shown in table 2 using the best available information derived from what is known of the existing Cargo Terminals site and the POA's experience with similar construction and demolition projects. A typical construction season at the POA extends from approximately mid-April to mid-October (6 months) and may include November. Exact dates of ice-out in the spring and formation of new ice in the fall vary from year to year and cannot be predicted with accuracy. In-water pile installation and removal cannot occur during the winter months when ice is present because of the hazards associated with moving ice floes that change directions four times a day, preventing the use of tugs, barges, workboats, and other vessels. Ice movement also prevents accurate placement of piles.
While the POA plans to conduct as much work as possible between April and July, when there is lower Cook Inlet beluga whale (CIBW; Delphinapterus leucas) abundance (see the Description of Marine Mammals in the Area of Specified Activities section for details on CIBW presence at the POA), front-loading of work is dependent on construction sequencing. Construction sequencing requires that temporary piles are installed as a template, then larger permanent piles are installed, and then the temporary piles are removed. This required sequence plays out many times, in this order, during the open water construction season. It is not possible to install all of the larger permanent piles during the early season and install temporary piles later in the season; the larger and smaller piles must be alternated. Exact project sequencing and installation and extraction methods are at the discretion of the construction crew. Construction dates may change because of unexpected project delays, ongoing construction activities in other areas of the POA, timing of ice-out and spring breakup, and other factors. Therefore, the estimated schedule (table 2) reflects a realistic scenario for the proposed project, but conditions on the ground may result in slight changes to this estimated schedule.
Table 1—Pile Installation and Removal Methods, Estimated Amounts, and Estimated Durations for Years 1-5
| Activity type | Pile size and type | Total estimated number of piles | Estimated number of piles in the water | Average vibratory duration per pile (minutes) | Average impact duration per pile (minutes) | Estimated impact strikes per pile | Total duration of removal or installation in water (hours) | Average production rate, piles per day (range) | Estimated number of days over 5 years |
| Temporary pile installation | 24- or 36-in (61- or 91-cm) Steel pipe | 565 | 450 | 30 | | | 225 hours | 2-4 | 144. |
| Temporary pile removal | 24- or 36-in (61- or 91-cm) Steel pipe | 161 | 46 | 45 | | | 35 hours | 2-4 | 15. |
| Permanent pile installation | 72-in (182-cm) Steel pipe | 310 | 275 | 10 | 86 | 5,743 | 440 hours | 0.5-3 | 159. |
| Total | | 1,036 | 771 | | | | 700 hours | | 337 days. |
| Note: cm = centimeter(s); 1—Piles installed above the mean lower low water line are considered “in the dry” ( i.e., not in-water). It is anticipated that the permanent and temporary piles in the three bents nearest the shore for all five trestles would be installed in the dry at low tide levels. An additional bent would be installed in the dry for the northernmost trestle of T1 and for the three trestles of T2. These piles are not considered to have the potential for impact to marine mammals and are thus excluded from the following analyses. |
Table 2—Estimated Timing and Duration (in Hours per Month) of Pile Installation and Removal Activities
| Activity | Duration (hours of activity by month and year) |
| Apr | May | Jun | Jul | Aug | Sep | Oct | Nov |
| Imp | Vib | Imp | Vib | Imp | Vip | Imp | Vib | Imp | Vib | Imp | Vib | Imp | Vib | Imp | Vib |
| Year 1—2026 |
| 24- or 36-in Temporary Pile Installation | | 2.5 | | 6.0 | | 6.0 | | 6.0 | | 6.0 | | 6.0 | | 3.0 | | 2 |
| 24- or 36-in Temporary Pile Removal | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 |
| 72-in Permanent Pile Installation | 7.2 | 0.8 | 15.8 | 1.8 | 15.8 | 1.8 | 15.8 | 1.8 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 5.7 | 0.7 |
| Year 1 total hours | 7.2 | 4.1 | 15.8 | 8.6 | 15.8 | 8.6 | 15.8 | 8.6 | 12.9 | 8.3 | 12.9 | 8.3 | 12.9 | 5.3 | 5.7 | 3.4 |
| Year 2—2027 |
| 24- or 36-in Temporary Pile Installation | | 3.0 | | 5.0 | | 5.0 | | 5.0 | | 5.0 | | 5.0 | | 2.5 | | 2 |
| 24- or 36-in Temporary Pile Removal | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | |
| 72-in Permanent Pile Installation | 7.2 | 0.8 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 11.5 | 1.3 | 11.5 | 1.3 | 5.7 | 0.7 |
| Year 2 total hours | 7.2 | 4.6 | 12.9 | 7.3 | 12.9 | 7.3 | 12.9 | 7.3 | 12.9 | 7.3 | 11.5 | 7.1 | 11.5 | 4.6 | 5.7 | 2.7 |
| Year 3—2028 |
| 24- or 36-in Temporary Pile Installation | | 6.5 | | 13.0 | | 13.0 | | 13.0 | | 13.0 | | 13.0 | | 6.5 | | 2 |
| 24- or 36-in Temporary Pile Removal | | 0.8 | | 2.3 | | 2.3 | | 2.3 | | 1.5 | | 1.5 | | 0.8 | | 0.8 |
| 72-in Permanent Pile Installation | 5.7 | 0.7 | 5.7 | 0.7 | 5.7 | 0.7 | 4.3 | 0.5 | 4.3 | 0.5 | 4.3 | 0.5 | 4.3 | 0.5 | 4.3 | 0.5 |
| Year 3 total hours | 5.7 | 7.9 | 5.7 | 15.9 | 5.7 | 15.9 | 4.3 | 15.8 | 4.3 | 15.0 | 4.3 | 15.0 | 4.3 | 7.8 | 4.3 | 3.3 |
| Year 4—2029 |
| 24- or 36-in Temporary Pile Installation | | 2.5 | | 5.5 | | 5.5 | | 6.0 | | 5.5 | | 5.5 | | 2.5 | | 2 |
| 24- or 36-in Temporary Pile Removal | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | 0.8 | | |
| 72-in Permanent Pile Installation | 7.2 | 0.8 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 11.5 | 1.3 | 11.5 | 1.3 | 5.7 | 0.7 |
| Year 4 total hours | 7.2 | 4.1 | 12.9 | 7.8 | 12.9 | 7.8 | 12.9 | 8.3 | 12.9 | 7.8 | 11.5 | 7.6 | 11.5 | 4.6 | 5.7 | 2.7 |
| Year 5—2030 |
| 24- or 36-in Temporary Pile Installation | | 2.5 | | 6.0 | | 6.0 | | 6.0 | | 6.0 | | 5.5 | | 5.5 | | 2.5 |
| 24- or 36-in Temporary Pile Removal | | 0.8 | | 0.8 | | 1.5 | | 1.5 | | 0.8 | | 0.8 | | 0.8 | | 0.8 |
| 72-in Permanent Pile Installation | 4.3 | 0.5 | 12.9 | 1.5 | 12.9 | 1.5 | 12.9 | 1.5 | 11.5 | 1.3 | 11.5 | 1.3 | 11.5 | 1.3 | 4.3 | 0.5 |
| Year 5 total hours | 4.3 | 3.8 | 12.9 | 8.3 | 12.9 | 8.3 | 12.9 | 8.3 | 11.5 | 8.1 | 11.5 | 7.6 | 11.5 | 7.6 | 4.3 | 3.8 |
| Duration estimates assume a single hammer active at any time and therefore likely overestimates of actual time needed due to simultaneous pile installation and removal; |
| Impact pile installation; |
| Vibratory pile installation or extraction; |
| To account for piles driven in water less than 3m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5 minutes of vibratory driving) each month. Numbers may not add exactly due to rounding. |
Table 3—Potential Concurrent Driving Scenarios That Could Occur During CTR Construction
| Equipment type and quantity | Pile type and size | Construction months |
| Vibratory × 2 | 2 x 36-in steel pipe | April-July. |
| Vibratory, Impact | 2 x 72-in steel pipe OR 1 x 72-in steel pipe (impact) and 1 x 36-in steel pipe (vibratory) | April-November. |
| POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to have larger ensonified areas, we have used these piles in our analyses of concurrent activities; |
| All 72-in piles driven concurrently will be attenuated. |
Table 4—Species Likely Impacted by the Specified Activities
| Common name | Scientific name | MMPA stock | ESA/ MMPA status; strategic (Y/N) | Stock abundance Nbest, (CV, Nmin, most recent abundance survey) | PBR | Annual M/SI |
| Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales) |
| Family Eschrichtiidae: | | | | | | |
| Gray whale | Eschrichtius robustus | Eastern N Pacific | -/-; N | 26,960 (0.05, 25,849, 2016) | 801 | 131 |
| Family Balaenopteridae (rorquals): | | | | | | |
| Humpback whale | Megaptera novaeangliae | Hawaii | -, -, N | 11,278 (0.56, 7,265, 2020) | 127 | 27.09 |
| | | Mexico-North Pacific | T, D, Y | N/A (N/A, N/A, 2006) | UND | 0.57 |
| Order Cetartiodactyla—Superfamily Odontoceti (toothed whales, dolphins, and porpoises) |
| Family Delphinidae: | | | | | | |
| Killer whale | Orcinus orca | Eastern North Pacific Alaska Resident | -/-; N | 1,920 (N/A, 1,920, 2019) | 19 | 1.3 |
| | | Eastern North Pacific Gulf of Alaska, Aleutian Islands and Bering Sea Transient | -/-; N | 587 (N/A, 587, 2012) | 5.9 | 0.8 |
| Family Monodontidae: | | | | | | |
| Beluga whale | Delphinapterus leucas | Cook Inlet | E/D; Y | 331 (0.076, 290, 2022) | 0.53 | 0 |
| Family Phocoenidae (porpoises): | | | | | | |
| Harbor porpoise | Phocoena phocoena | Gulf of Alaska | -/-; Y | 31,046 (0.214, N/A, 1998) | UND | 72 |
| Order Carnivora—Superfamily Pinnipedia |
| Family Otariidae (eared seals and sea lions): | | | | | | |
| Steller sea lion | Eumetopias jubatus | Western | E/D; Y | 49,837 (N/A, 49,837 2022) | 299 | 267 |
| Family Phocidae (earless seals): | | | | | | |
| Harbor seal | Phoca vitulina | Cook Inlet/Shelikof Strait | -/-; N | 28,411 (N/A, 26,907, 2018) | 807 | 107 |
| Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock. |
| NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.). |
| These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined ( e.g., commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. |
| This abundance estimate is from Goetz et al. (2023); which was published after the most recent CIBW SAR (Young et al., 2023). |
| UND means undetermined. |
Table 5—Marine Mammal Hearing Groups
[NMFS, 2018]
| Hearing group | Generalized hearing range * |
| Low-frequency (LF) cetaceans (baleen whales) | 7 Hz to 35 kHz. |
| Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) | 150 Hz to 160 kHz. |
| High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, Cephalorhynchid, Lagenorhynchus cruciger & L. australis) | 275 Hz to 160 kHz. |
| Phocid pinnipeds (PW) (underwater) (true seals) | 50 Hz to 86 kHz. |
| Otariid pinnipeds (OW) (underwater) (sea lions and fur seals) | 60 Hz to 39 kHz. |
| * Represents the generalized hearing range for the entire group as a composite ( i.e., all species within the group), where individual species' hearing ranges are typically not as broad. Generalized hearing range chosen based on ~65 dB threshold from normalized composite audiogram, with the exception for lower limits for LF cetaceans (Southall et al. 2007) and PW pinniped (approximation). |
Table 6—Marine Mammal Hearing Groups
[NMFS 2024]
| Hearing group | Generalized hearing range * |
| Underwater: | |
| Low-frequency (LF) cetaceans (baleen whales) | 7 Hz to 36 kHz. |
| High-frequency (HF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) | 150 Hz to 160 kHz. |
| Very High-frequency (VHF) cetaceans (true porpoises, Kogia, river dolphins, Cephalorhynchid, Lagenorhynchus cruciger & L. australis) | 200 Hz to 165 kHz. |
| Phocid pinnipeds (PW) (underwater) (true seals) | 40 Hz to 90 kHz. |
| Otariid pinnipeds (OW) (underwater) (sea lions and fur seals) | 60 Hz to 68 kHz. |
| In-air: | |
| Phocid pinnipeds (PA) (true seals) | 42 Hz to 52 kHz. |
| Otariid pinnipeds (OA) (sea lions and fur seals) | 90 Hz to 40 kHz. |
| * Represents the generalized hearing range for the entire group as a composite ( i.e., all species within the group), where individual species' hearing ranges may not be as broad. Generalized hearing range chosen based on ~65 dB threshold from composite audiogram, previous analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall et al. 2019. Additionally, animals are able to detect very loud sounds above and below that “generalized” hearing range |
Table 7—NMFS' 2018 Thresholds Identifying the Onset of Permanent Threshold Shift (PTS)
| Hearing group | PTS onset acoustic thresholds * (received level) |
| Impulsive | Non-impulsive |
| Low-Frequency (LF) Cetaceans | Cell 1: L pk,flat : 219 dB; L E,LF,24h : 183 dB | Cell 2: L E,LF,24h : 199 dB. |
| Mid-Frequency (MF) Cetaceans | Cell 3: L pk,flat : 230 dB; L E,MF,24h : 185 dB | Cell 4: L E,MF,24h : 198 dB. |
| High-Frequency (HF) Cetaceans | Cell 5: L pk,flat : 202 dB; L E,HF,24h : 155 dB | Cell 6: L E,HF,24h : 173 dB. |
| Phocid Pinnipeds (PW)(Underwater) | Cell 7: L pk,flat : 218 dB; L E,PW,24h : 185 dB | Cell 8: L E,PW,24h : 201 dB. |
| Otariid Pinnipeds (OW)(Underwater) | Cell 9: L pk,flat : 232 dB; L E,OW,24h : 203 dB | Cell 10: L E,OW,24h : 219 dB. |
| * Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should also be considered. |
| Note: Peak sound pressure ( L pk ) has a reference value of 1 µPa, and cumulative sound exposure level ( L E ) has a reference value of 1µPa s. In this Table, thresholds are abbreviated to reflect American National Standards Institute standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as incorporating frequency weighting, which is not the intent for NMFS' 2018 Technical Guidance. Hence, the subscript “flat” is being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be exceeded in a multitude of ways ( i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be exceeded. |
Table 8—NMFS' 2024 Thresholds Identifying the Onset of Auditory Injury (AUD INJ)
| Hearing group | AUD INJ acoustic thresholds * (received level) |
| Impulsive | Non-impulsive |
| Underwater: | | |
| Low-Frequency (LF) Cetaceans | Cell 1: L p,0-pk,flat : 222 dB; L E,p,LF,24h : 183 dB | Cell 2: L E,p,LF,24h : 197 dB. |
| High-Frequency (HF) Cetaceans | Cell 3: L p,0-pk,flat : 230 dB; L E,p,HF,24h : 193 dB | Cell 4: L E,p,HF,24h : 201 dB. |
| Very High-Frequency (VHF) Cetaceans | Cell 5: L p,0-pk,flat : 202 dB; L E,p,VHF,24h : 159 dB | Cell 6: L E,p,VHF,24h : 181 dB. |
| Phocid Pinnipeds (PW) (Underwater) | Cell 7: L p,0-pk.flat : 223 dB; L E,p,PW,24h : 183 dB | Cell 8: L E,p,PW,24h : 195 dB. |
| Otariid Pinnipeds (OW) (Underwater) | Cell 9: L p,0-pk,flat : 230 dB; L E,p,OW,24h : 185 dB | Cell 10: L E,p,OW,24h : 199 dB. |
| In-air: | | |
| Phocid Pinnipeds (PA) (In-Air) | Cell 11: L p,0-pk.flat : 162 dB; L E,p,PA,24h : 140 dB | Cell 12: L E,p,PA,24h : 154 dB. |
| Otariid Pinnipeds (OA) (In-Air) | Cell 13: L p,0-pk,flat : 177 dB; L E,p,OA,24h : 163 dB | Cell 14: L E,p,OA,24h : 177 dB. |
| * Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should also be considered. |
| Note: Peak sound pressure ( L pk ) has a reference value of 1 µPa, and cumulative sound exposure level ( L E ) has a reference value of 1µPa s. In this Table, thresholds are abbreviated to reflect American National Standards Institute standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as incorporating frequency weighting, which is not the intent for NMFS' 2018 Technical Guidance. Hence, the subscript “flat” is being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be exceeded in a multitude of ways ( i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be exceeded. |
Table 9—Summary of Unattenuated In-Water Pile Driving Proxy Levels
[at 10 m]
| Vibratory hammer |
| Method and pile type | dB rms | TL coefficient | Data source for source levels |
| 24-in steel installation | 161 | 16.5 | U.S. Navy 2015. |
| 24-in steel removal | 169 | | NMFS average 2023; see 89 FR 2832. |
| 36-in steel installation | 166 | | U.S. Navy 2015. |
| 36-in steel removal | 159 | | NMFS average 2023; see 89 FR 2832. |
| 72-in steel | 171 | | I&R 2003, unpublished data for Castrol Oil berthing dolphin in Richmond, CA. |
| Impact hammer |
| | dB rms | dB SEL | dB peak | TL coefficient | Data source for source levels |
| 24-in steel | 193 | 181 | 210 | 15.0 | U.S. Navy 2015. |
| 36-in steel | 193 | 184 | 211 | | U.S. Navy 2015. |
| 72-in steel | 203 | 191 | 217 | | I&R model. Estimate based on interpolation of data for piles 24 to 144 inches in diameter. |
Table 10—Summary of Attenuated In-Water Pile Driving Proxy Levels
[at 10 m]
| Vibratory hammer |
| Method and pile type | dB rms | TL coefficient | Reference for proxy levels |
| 24-in steel installation | 158.5 | 15.0 | I&R 2021a (measured). |
| 24-in steel removal | 157 | | I&R 2021a (measured). |
| 36-in steel installation | 160.5 | | I&R 2021a, 2021b (measured). |
| 36-in steel removal | 154 | | I&R 2021a (measured). |
| 72-in steel | 164 | | Assumed 7-dB reduction supported by I&R 2021a. |
| Impact hammer |
| | dB rms | dB SEL | dB peak | TL coefficient | Reference for proxy levels |
| 24-in steel | 186 | 174 | 203 | 15.0 | Assumed 7-dB reduction supported by I&R 2021a. |
| 36-in steel | 186 | 177 | 204 | | Assumed 7-dB reduction supported by I&R 2021a. |
| 72-in steel | 196 | 184 | 210 | | Assumed 7-dB reduction supported by Caltrans Compendium (2020). |
Table 11—Source Values for Potential Concurrent Driving Scenarios
| Activity | Method | Pile type/size | Attenuated or unattenuated | Proxy source value | TL coefficient | # Piles per day |
| dB RMS | dB SEL | dB peak |
| Concurrent Driving (2 sources) | Vibratory/Vibratory | 36-in and 36-in | Attenuated/Attenuated Attenuated/Unattenuated Unattenuated/Unattenuated | 163.5 169 171 | | | 15 15.75 16.5 | 8 8 8 |
| | | 36-in and 72-in | Attenuated/Attenuated Unattenuated/Attenuated | 166 169 | | | 15 15.75 | 7 7 |
| | Vibratory/Impact | 36-in and 72-in | Attenuated/Attenuated Unattenuated/Attenuated | 160.5/196 166/196 | —/184 —/184 | —/210 —/210 | 15/15 16.5/15 | 8 7 |
| Concurrent vibratory and impact driving source values and TL coefficients are the same as for the piles driven individually (shown in tables 7 and 8), with no adjustments for concurrent driving. The Level A harassment isopleths would be determined by the calculated impact pile driving isopleths, and Level B harassment isopleth would be generated by vibratory pile driving. |
| POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to have larger ensonified areas, we have used these piles in our analyses of concurrent activities. |
| Piles per day were calculated as the maximum daily number of each type of pile (24-in and 36-in = 4 piles per hammer per day; 72-in piles = 3 piles per day) with complete overlap for 45 minutes of driving with the largest possible combined source value, a scenario that would over-estimate duration of noise production given the estimated time required to drive 72-in piles with a vibratory hammer (10 minutes). |
Table 12—NMFS User Spreadsheet Inputs for 72-in Permanent Piles
| | Impact pile driving | Vibratory pile driving |
| Attenuated | Unattenuated | Attenuated | Unattenuated |
| Spreadsheet tab used | (E.1) Impact pile driving | (A.1) Non-Impul, Stat, Cont. |
| Source Level | 184 dB SEL | 191 dB SEL | 164 dB RMS | 171 dB RMS |
| Transmission Loss Coefficient | 15 | 15 | 15 | 16.5 |
| Weighting Factor Adjustment (kHz) | 2 | 2.5 |
| Time to install single pile (minutes) | — | 10 |
| Number of strikes per pile | 5,743 | — |
| Piles per day | 1—3 | 1 | 3 |
| Distance of sound pressure level measurement (m) | 10 |
| To account for piles driven in water less than 3m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5 minutes of vibratory driving) each month. |
Table 13—NMFS User Spreadsheet Inputs for Temporary (24- or 36- in ) Piles
| Vibratory pile driving |
| | 24-in (61-cm) steel pipe | 36-in (91-cm) steel pipe |
| Installation | Removal | Installation | Removal |
| Atten. | Unatten. | Atten. | Unatten. | Atten. | Unatten. | Atten. | Unatten. |
| Spreadsheet Tab Used | (A.1) Non-Impul, Stat, Cont. |
| Source Level (dB RMS) | 158.5 | 161 | 157 | 169 | 160.5 | 166 | 154 | 159 |
| Transmission Loss Coefficient | 15 | 16.5 | 15 | 16.5 | 15 | 16.5 | 15 | 16.5 |
| Weighting Factor Adjustment (kHz) | 2.5 |
| Time to install or remove single pile (minutes) | 30 | 45 | 30 | 45 |
| Number of strikes per pile | — |
| Piles per day | 4 |
| Distance of sound pressure level measurement (m) | 10 |
| Impact Pile Driving |
| | 24-in (61-cm) steel pipe | 36-in (91-cm) steel pipe |
| | Attenuated | Unattenuated | Attenuated | Unattenuated |
| Spreadsheet Tab Used | (E.1) Impact pile driving |
| Source Level (dB RMS) | 174 dB SEL | 181 dB SEL | 177 dB SEL | 184 dB SEL |
| Transmission Loss Coefficient | 15 |
| Weighting Factor Adjustment (kHz) | 2 |
| Time to install or remove single pile (minutes) | — |
| |
| Number of strikes per pile | 1,000 |
| Piles per day | 1 |
| Distance of sound pressure level measurement (m) | 10 |
Table 14—NMFS User Spreadsheet Inputs for Concurrent Vibratory Driving
| | 24- or 36-in AND 24-in or 36-in | 24- or 36-in AND 72-in |
| Attenuated/ attenuated | Attenuated/ unattenuated | Unattenuated/ unattenuated | Attenuated/ attenuated | Unattenuated/ attenuated |
| Spreadsheet Tab Used | (A.1) Non-Impul, Stat, Cont. |
| Source Level (dB RMS) | 163.5 | 170 | 172 | 166 | 170 |
| Transmission Loss Coefficient | 15 | 15.75 | 16.5 | 15 | 15.75 |
| Weighting Factor Adjustment (kHz) | 2.5 |
| Time to install or remove a single pile (minutes) | 45 |
| Number of strikes per pile | — |
| Piles per day | 8 | 7 |
| Distance of sound pressure level measurement (m) | 10 |
Table 15—Calculated Distance of Level A (based on NMFS' 2018 Technical Guidance) and Level B Harassment Isopleths by Pile Type and Pile Driving Method
| Activity | Pile type/size | Attenuated or unattenuated | Level A harassment distance (m) | Level B harassment distance (m) all hearing groups |
| LF | MF | HF | PW | OW |
| Impact | 24-in (61-cm) | Unattenuated | 735 | 27 | 876 | 394 | 29 | 1,585 |
| | | Attenuated | 251 | 9 | 299 | 135 | 10 | 541 |
| | 36-in (91-cm) | Unattenuated | 1,165 | 42 | 1,387 | 624 | 46 | 1,585 |
| | | Attenuated | 398 | 15 | 474 | 213 | 16 | 541 |
| | 72-in (182-cm) | Unattenuated | 10,936 | 389 | 13,026 | 5,853 | 427 | 7,356 |
| | | Attenuated (1 pile per day) | 3,734 | 133 | 4,448 | 1,999 | 146 | 2,512 |
| | | Attenuated (2 piles per day) | 5,928 | 211 | 7,061 | 3,173 | 231 | |
| | | Attenuated (3 piles per day) | 7,767 | 277 | 9,252 | 4,157 | 303 | |
| Vibratory Installation | 24-in (61-cm) | Unattenuated | 11 | 2 | 16 | 7 | 1 | 2,247 |
| | | Attenuated | 8 | 1 | 11 | 5 | 1 | 2,630 |
| | 36-in (91-cm) | Unattenuated | 22 | 3 | 31 | 14 | 2 | 4,514 |
| | | Attenuated | 11 | 1 | 15 | 7 | 1 | 3,575 |
| | 72-in (182-cm) | Unattenuated | 19 | 3 | 27 | 12 | 2 | 9,069 |
| | | Attenuated | 7 | 1 | 11 | 5 | 1 | 6,119 |
| Vibratory Removal | 24-in (61-cm) | Unattenuated | 42 | 4.6 | 60 | 27 | 2.4 | 6,861 |
| | | Attenuated | 16 | 1.7 | 23 | 11 | 1 | 2,583 |
| | 36-in (91-cm) | Unattenuated | 11 | 2 | 15 | 7 | 1 | 1,699 |
| | | Attenuated | 5 | 1 | 8 | 3 | 1 | 1,318 |
| Concurrent Vibratory | 36-in AND 36-in | Attenuated/Attenuated | 33 | 2.9 | 49 | 20 | 1.4 | 5,667 |
| | | Attenuated/Unattenuated | 81 | 8.0 | 118 | 51 | 4.0 | 9,363 |
| | | Unattenuated/Unattenuated | 98 | 11 | 139 | 62 | 5.5 | 9,069 |
| | 36-in AND 72-in | Attenuated/Attenuated | 45 | 3.9 | 66 | 27 | 1.9 | 8,318 |
| | | Unattenuated/Attenuated | 75 | 7.4 | 108 | 47 | 3.7 | 9,363 |
| Concurrent Vibratory/Impact | 36-in AND 72-in | Attenuated/Attenuated (1 pile per day) | 3,734 | 133 | 4,448 | 1,999 | 146 | 3,575 |
| | | Attenuated/Attenuated (2 piles per day) | 5,928 | 211 | 7,061 | 3,173 | 231 | |
| | | Attenuated/Attenuated (3 piles per day) | 7,767 | 277 | 9,252 | 4,157 | 303 | |
| | | Unattenuated/Attenuated (1 pile per day) | 3,734 | 133 | 4,448 | 1,999 | 146 | 4,514 |
| | | Unattenuated/Unattenuated (2 piles per day) | 5,928 | 211 | 7,061 | 3,173 | 231 | |
| | | Unattenuated/Attenuated (3 piles per day) | 7,767 | 277 | 9,252 | 4,157 | 303 | |
| Distances to thresholds are as modeled; however, interaction with shorelines would truncate zones. See figures 6-1 thorough 6-10 in the POA's application for further details. |
Table 16—Calculated Distance and Areas of Level A (based on NMFS' Proposed 2024 Update to the 2018 Technical Guidance) and Level B Harassment Isopleths by Pile Type and Pile Driving Method
| Activity | Pile type/size | Attenuated or unattenuated | Level A harassment distance (m) | Level B harassment distance (m) all hearing groups |
| LF | HF | VHF | PW | OW |
| Impact | 24-in (61-cm) | Unattenuated | 732 | 94 | 1,133 | 651 | 243 | 1,585 |
| | | Attenuated | 250 | 32 | 387 | 222 | 83 | 541 |
| | 36-in (91-cm) | Unattenuated | 1,160 | 148 | 1,796 | 1,031 | 385 | 1,585 |
| | | Attenuated | 397 | 51 | 613 | 352 | 132 | 541 |
| | 72-in (182-cm) | Unattenuated | 10,896 | 1,390 | 16,861 | 9,679 | 3,608 | 7,356 |
| | | Attenuated (1 pile per day) | 3,720 | 474.7 | 5,757 | 3,305 | 1,232 | 2,512 |
| | | Attenuated (2 piles per day) | 5,906 | 753.5 | 9,139 | 5,246 | 1,956 | |
| | | Attenuated (3 piles per day) | 7,739 | 987.4 | 11,976 | 6,875 | 2,563 | |
| Vibratory Installation | 24-in (61-cm) | Unattenuated | 14.1 | 5.9 | 11.8 | 17.8 | 6.6 | 2,247 |
| | | Attenuated | 10 | 3.8 | 8.1 | 12.8 | 4.3 | 2,630 |
| | 36-in (91-cm) | Unattenuated | 28.4 | 11.9 | 23.6 | 35.7 | 13.3 | 4,514 |
| | | Attenuated | 13.6 | 5.2 | 11.1 | 17.5 | 5.9 | 3,575 |
| | 72-in (182-cm) | Unattenuated | 24.6 | 10.3 | 20.5 | 31 | 11.5 | 9,069 |
| | | Attenuated | 9.2 | 3.5 | 7.5 | 11.9 | 4 | 6,119 |
| Vibratory Removal | 24-in (61-cm) | Unattenuated | 55.2 | 23.1 | 45.9 | 69.5 | 25.8 | 6,861 |
| | | Attenuated | 10.4 | 4 | 8.5 | 13.4 | 4.5 | 2,583 |
| | 36-in (91-cm) | Unattenuated | 13.7 | 5.7 | 11.4 | 17.2 | 6.4 | 1,699 |
| | | Attenuated | 6.6 | 2.5 | 5.4 | 8.4 | 2.8 | 1,318 |
| Concurrent Vibratory/Vibratory | 36-in AND 36-in | Attenuated/Attenuated | 44.7 | 17.2 | 36.5 | 57.5 | 19.4 | 5,667 |
| | | Attenuated/Unattenuated | 107.6 | 43.3 | 88.8 | 136.9 | 48.5 | 9,363 |
| | | Unattenuated/Unattenuated | 127.7 | 53.5 | 106.3 | 160.7 | 59.7 | 9,069 |
| | 36-in AND 72-in | Attenuated/Attenuated | 60 | 23.1 | 49 | 77.3 | 26 | 8,318 |
| | | Unattenuated/Attenuated | 98.9 | 39.8 | 81.6 | 125.8 | 44.6 | 9,363 |
| Concurrent Vibratory/Impact | | Attenuated/Attenuated (1 pile per day) | 3,720 | 474.7 | 5,757 | 3,305 | 1,232 | 3,575 |
| | | Attenuated/Attenuated (2 piles per day) | 5,906 | 753.5 | 9,139 | 5,246 | 1,956 | |
| | | Attenuated/Attenuated (3 piles per day) | 7,739 | 987.4 | 11,976 | 6,875 | 2,563 | |
| | 36-in AND 72-in | Unattenuated/Attenuated (1 pile per day) | 3,720 | 474.7 | 5,757 | 3,305 | 1,232 | 4,514 |
| | | Unattenuated/Attenuated (2 piles per day) | 5,906 | 753.5 | 9,139 | 5,246 | 1,956 | |
| | | Unattenuated/Attenuated (3 piles per day) | 7,739 | 987.4 | 11,976 | 6,875 | 2,563 | |
| Distances to thresholds are as modeled; however, interaction with shorelines would truncate zones. See figures 6-1 thorough 6-10 in the POA's application for further details. |
Table 17—Estimated Occurrence for Non-CIBW Species at the POA
| Species | Timeframe | Estimated occurrence rates | Estimated annual occurrence | Estimated 5-year occurrence |
| Gray whale | Yearly | 6/year | 6 | 30 |
| Humpback whale | | 4/year | 4 | 20 |
| Killer whale | | 6/year | 6 | 30 |
| Steller sea lion | | 9/year | 9 | 45 |
| Harbor porpoise | Hourly | 0.15/hour | 1,314 | 6,570 |
| Harbor seal | | 1/hour | 8,760 | 43,800 |
Table 18—Marine Mammal Monitoring Data Used for CIBW Sighting Rate Calculations
| Year | Monitoring type and data source | Number of CIBW group fixes | Number of CIBW groups | Number of CIBWs |
| 2020 | PCT: POA Construction Monitoring 61N Environmental, 2021 | 2,653 | 245 | 987 |
| 2021 | PCT: NMFS Monitoring Easley-Appleyard and Leonard, 2022 | 694 | 109 | 575 |
| 2021 | PCT: POA Construction Monitoring 61N Environmental, 2021, 2022a | 1,339 | 132 | 517 |
| 2022 | SFD: POA Construction Monitoring 61N Environmental, 2022b | 151 | 9 | 41 |
| This number differs slightly from Table 6-8 in the POA's application due to our removal of a few duplicate data points in the NMFS data set. |
Table 19—CIBW Monthly Sighting Rates for Different Spatially-Based Bin Sizes
| Bin number | Distance (m) | CIBW/Hour |
| April | May | June | July | August | September | October | November |
| 1 | 196 | 0.05 | 0.06 | 0.10 | 0.04 | 0.82 | 0.59 | 0.51 | 0.10 |
| 2 | 2,338 | 0.34 | 0.16 | 0.15 | 0.09 | 1.55 | 1.42 | 1.09 | 0.65 |
| 3 | 3,155 | 0.36 | 0.22 | 0.21 | 0.09 | 2.02 | 1.89 | 1.98 | 0.72 |
| 4 | 6,974 | 0.67 | 0.33 | 0.29 | 0.13 | 2.24 | 2.18 | 2.42 | 0.73 |
| 5 | >6,974 | 0.71 | 0.39 | 0.30 | 0.13 | 2.29 | 2.23 | 2.56 | 0.73 |
| Observation hours have been totaled from the PCT 2020 and 2021 programs, the NMFS 2021 data collection effort, and the SFD 2022 program (61N Environmental 2021, 2022a, 2022b; Easley-Appleyard and Leonard, 2022). |
Table 20—Estimated Predicted Number of Hours of Impact and Vibratory Hammer Use for Each Construction Year
| Year | Impact duration (hrs) | Vibratory duration (hrs) | Total duration (hrs) | Proportion of impact hammer use |
| 1 | 98.90 | 55.00 | 153.90 | 0.64 |
| 2 | 87.43 | 47.92 | 135.35 | 0.65 |
| 3 | 38.70 | 96.50 | 135.20 | 0.29 |
| 4 | 87.43 | 50.42 | 137.85 | 0.63 |
| 5 | 81.70 | 55.50 | 137.20 | 0.60 |
Table 21—Estimated Take by Level A Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal Species in the Proposed CTR Project Area
| Species | Potential level A harassment by year |
| 1 | 2 | 3 | 4 | 5 | Total |
| Gray whale | 4 | 4 | 2 | 4 | 4 | 18 |
| Humpback whale | 3 | 3 | 1 | 3 | 2 | 12 |
| Killer whale | 6 | 6 |
| Harbor porpoise | 15 | 13 | 6 | 13 | 12 | 59 |
| Steller sea lion | 6 | 6 | 3 | 6 | 5 | 26 |
| Harbor seal | 98 | 88 | 39 | 87 | 82 | 394 |
| Annual take may not be distributed exactly as shown; NMFS proposes to authorize total take over the 5 year construction period, with annual take by Level A harassment for each species not to exceed the maximum annual value shown in years 1-5. |
Table 22—Estimated Take by Level B Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal Species in the Proposed CTR Project Area
| Stock | Potential level B harassment by year |
| 1 | 2 | 3 | 4 | 5 | Total |
| Gray whale | 2 | 2 | 4 | 2 | 2 | 12 |
| Humpback whale | 1 | 1 | 3 | 1 | 2 | 8 |
| Killer whale | 6 | 6 | 6 | 6 | 6 | 30 |
| Harbor porpoise | 8 | 7 | 14 | 8 | 8 | 45 |
| Steller sea lion | 3 | 3 | 6 | 3 | 4 | 20 |
| Harbor seal | 55 | 47 | 96 | 51 | 55 | 304 |
| Annual take may not be distributed exactly as shown; NMFS proposes to authorize total take over the 5 year construction period, not to exceed the sum of the maximum annual values shown in years 1-5 in Tables 21 and 22. |
Table 23—Allocation of Each Level B Harassment Isopleth to a Sighting Rate Bin and CIBW Monthly Sighting Rates for Different Pile Sizes and Hammer Types
| Activity | Level B isopleth distance (m) | Sighting rate bin number and distance | Belugas/Hour |
| Apr | May | Jun | Jul | Aug | Sep | Oct | Nov |
| Unattenuated Values (without the use of a bubble curtain) |
| 36-in Vibratory Removal | 1,699 | 2 (2,338 m) | 0.34 | 0.16 | 0.15 | 0.09 | 1.55 | 1.42 | 1.09 | 0.65 |
| 36-in Vibratory Installation | 4,514 | 4 (6,974 m) | 0.67 | 0.33 | 0.29 | 0.13 | 2.24 | 2.18 | 2.42 | 0.73 |
| 72-in Vibratory Installation | 9,069 | 5 (>6,974) | 0.71 | 0.39 | 0.30 | 0.13 | 2.29 | 2.23 | 2.56 | 0.73 |
| Concurrent 36-in AND 36-in Vibratory Installation | 9,069 | | | | | | | | | |
| Concurrent 36-in AND 36-in OR 72-in Vibratory Installation | 9,363 | | | | | | | | | |
| 36-in Impact Installation | 1,585 | 2 (2,338 m) | 0.34 | 0.16 | 0.15 | 0.09 | 1.55 | 1.42 | 1.09 | 0.65 |
| 72-in Impact Installation | 7,356 | 5 (>6,974) | 0.71 | 0.39 | 0.30 | 0.13 | 2.29 | 2.23 | 2.56 | 0.73 |
| Attenuated Values (with the use of a bubble curtain) |
| 36-in Vibratory Removal | 1,318 | 2 (2,338) | 0.34 | 0.16 | 0.15 | 0.09 | 1.55 | 1.42 | 1.09 | 0.65 |
| 36-in Vibratory Installation | 3,575 | 4 (6,974 m) | 0.67 | 0.33 | 0.29 | 0.13 | 2.24 | 2.18 | 2.42 | 0.73 |
| 72-in Vibratory Installation | 6,119 | | | | | | | | | |
| Concurrent 36-in AND 36-in Vibratory Installation | 5,667 | | | | | | | | | |
| Concurrent 36-in AND 72-in Vibratory Installation | 8,318 | 5 (>6,974) | 0.71 | 0.39 | 0.30 | 0.13 | 2.29 | 2.23 | 2.56 | 0.73 |
| 36-in Impact Installation | 541 | 2 (2,338) | 0.34 | 0.16 | 0.15 | 0.09 | 1.55 | 1.42 | 1.09 | 0.65 |
| 72-in Impact Installation | 2,512 | 3 (3,155 m) | 0.36 | 0.22 | 0.21 | 0.09 | 2.02 | 1.89 | 1.98 | 0.72 |
| Unattenuated vibratory and impact driving of temporary and permanent piles during the months of August through October would be limited to the minimum possible number of piles that must be driven in-water in depths <3 m. |
| Unattenuated and attenuated vibratory installation of 36-in temporary piles both result in bin 4; vibratory removal of this pile type results in bin 2 in both attenuated and unattenuated conditions. Unattenuated and attenuated impact pile driving of 36-in piles results in bin 2 in both conditions. |
| Unattenuated vibratory and impact installation of permanent (72-in) piles will be minimized to the extent possible by driving as many piles as possible in the dry for all months of the construction seasons. To account for piles driven in water less than 3 m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5 minutes of vibratory driving) each month. Impact driving (attenuated and unattenuated) results in Bin 2; vibratory driving (attenuated and unattenuated) results in Bin 5. |
| Both concurrent driving of 2 temporary piles (1 attenuated, 1 unattenuated) and 1 temporary (unattenuated) and 1 permanent (attenuated) piles result in a Level B harassment isopleth of 9,363 m. |
Table 24—Calculated Level B harassment Takes of CIBWs by Month, Year, and Activity
| | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov |
| Year 1 |
| 36″ vibratory installation | 1.68 | 2.01 | 1.76 | 0.78 | 13.44 | 13.10 | 7.26 | 1.47 |
| 36″ vibratory removal | 0.26 | 0.12 | 0.11 | 0.07 | 1.16 | 1.06 | 0.82 | 0.49 |
| |
| 72″ vibratory installation (attenuated) | 0.50 | 0.59 | 0.51 | 0.23 | 3.17 | 3.09 | 3.43 | 0.06 |
| 72″ vibratory installation (unattenuated) | 0.06 | 0.03 | 0.03 | 0.01 | 0.19 | 0.19 | 0.21 | 0.06 |
| 72″ impact installation (attenuated) | 2.35 | 3.36 | 3.19 | 1.40 | 24.67 | 23.08 | 24.18 | 3.62 |
| 72″ impact installation (unattenuated) | 0.49 | 0.27 | 0.21 | 0.09 | 1.60 | 1.56 | 1.79 | 0.51 |
| Year 1 total | | | | | | | | 151 |
| With 59% Correction Factor | | | | | | | | 90 |
| Year 2 |
| 36″ vibratory installation | 2.01 | 1.67 | 1.47 | 0.65 | 11.20 | 10.91 | 6.05 | 1.47 |
| 36″ vibratory removal | 0.26 | 0.12 | 0.11 | 0.07 | 1.16 | 1.06 | 0.82 | 0.00 |
| 72″ vibratory installation (attenuated) | 0.50 | 0.47 | 0.42 | 0.18 | 3.17 | 2.73 | 3.03 | 0.43 |
| 72″ vibratory installation (unattenuated) | 0.06 | 0.03 | 0.03 | 0.01 | 0.19 | 0.19 | 0.21 | 0.06 |
| 72″ impact installation (attenuated) | 2.35 | 2.72 | 2.58 | 1.14 | 24.67 | 20.36 | 21.34 | 3.62 |
| 72″ impact installation (unattenuated) | 0.49 | 0.27 | 0.21 | 0.09 | 1.60 | 1.56 | 1.79 | 0.51 |
| Year 2 total | | | | | | | | 137 |
| With 59% Correction Factor | | | | | | | | 81 |
| Year 3 |
| 36″ vibratory installation | 4.36 | 4.35 | 3.82 | 1.68 | 29.13 | 28.38 | 15.73 | 1.47 |
| 36″ vibratory removal | 0.26 | 0.37 | 0.34 | 0.21 | 2.33 | 2.12 | 0.82 | 0.49 |
| 72″ vibratory installation (attenuated) | 0.39 | 0.20 | 0.17 | 0.05 | 0.93 | 0.91 | 1.01 | 0.31 |
| 72″ vibratory installation (unattenuated) | 0.06 | 0.03 | 0.03 | 0.01 | 0.19 | 0.19 | 0.21 | 0.06 |
| 72″ impact installation (attenuated) | 1.83 | 1.12 | 1.07 | 0.34 | 7.28 | 6.81 | 7.13 | 2.59 |
| 72″ impact installation (unattenuated) | 0.49 | 0.27 | 0.21 | 0.09 | 1.60 | 1.56 | 1.79 | 0.51 |
| Year 3 total | | | | | | | | 136 |
| With 59% Correction Factor | | | | | | | | 81 |
| Year 4 |
| 36″ vibratory installation | 4.36 | 4.35 | 3.82 | 1.68 | 29.13 | 28.38 | 15.73 | 1.47 |
| 36″ vibratory removal | 0.26 | 0.37 | 0.34 | 0.21 | 2.33 | 2.12 | 0.82 | 0.49 |
| 72″ vibratory installation (attenuated) | 0.39 | 0.20 | 0.17 | 0.05 | 0.93 | 0.91 | 1.01 | 0.31 |
| 72″ vibratory installation (unattenuated) | 0.06 | 0.03 | 0.03 | 0.01 | 0.19 | 0.19 | 0.21 | 0.06 |
| 72″ impact installation (attenuated) | 1.83 | 1.12 | 1.07 | 0.34 | 7.28 | 6.81 | 7.13 | 2.59 |
| 72″ impact installation (unattenuated) | 0.49 | 0.27 | 0.21 | 0.09 | 1.60 | 1.56 | 1.79 | 0.51 |
| Year 4 total | | | | | | | | 138 |
| With 59% Correction Factor | | | | | | | | 82 |
| Year 5 |
| 36″ vibratory installation | 1.68 | 2.01 | 1.76 | 0.78 | 13.44 | 12.00 | 13.31 | 1.84 |
| 36″ vibratory removal | 0.26 | 0.12 | 0.11 | 0.07 | 1.16 | 1.06 | 0.82 | 0.49 |
| 72″ vibratory installation (attenuated) | 0.28 | 0.47 | 0.42 | 0.18 | 2.80 | 2.73 | 3.03 | 0.31 |
| 72″ vibratory installation (unattenuated) | 0.06 | 0.03 | 0.03 | 0.01 | 0.19 | 0.19 | 0.21 | 0.06 |
| 72″ impact installation (attenuated) | 1.31 | 2.72 | 2.58 | 1.14 | 21.77 | 20.36 | 21.34 | 2.59 |
| 72″ impact installation (unattenuated) | 0.49 | 0.27 | 0.21 | 0.09 | 1.60 | 1.56 | 1.79 | 0.51 |
| Year 5 total | | | | | | | | 143 |
| With 59% Correction Factor | | | | | | | | 85 |
| Years 1-5 Total |
| Project Total Estimated Exposures | | | | | | | | 705 |
| With 59% Correction Factor | | | | | | | | 419 |
| Concurrent driving scenarios that would improve the production efficiency in the months of April through July have been conservatively excluded from this analysis. |
| Unattenuated vibratory driving of temporary and permanent piles during the months of August through October would be limited to the minimum possible number of piles that must be driven in-water in depths <3m. |
| Attenuated and unattenuated bins for this activity are the same. |
| Unattenuated vibratory and impact installation of permanent (72-in) piles will be minimized to the extent possible by driving as many piles as possible in the dry for all months of the construction seasons. This calculation assumes 0.5 72-in piles per month may be driven in water depths <3m and thus be unattenuated. |
| Corrected exposure estimates have been rounded up for each year ( e.g., Year 1 = 0.59 * 151 = 89.1, which has been rounded up to 90). |
Table 25—Number of Proposed Takes as a Percentage of Stock Abundance, by Stock and Harassment Type for the Maximum Annual Estimated Takes of the Project
| Species | Proposed take | Stock | Percent of stock |
| Level A | Level B | Total |
| Gray whale | 4 | 2 | 6 | Eastern North Pacific | 0.02 |
| Humpback whale | 3 | 1 | 4 | Hawai'i | 0.04 |
| | | | | Mexico-North Pacific | UNK |
| Beluga whale | 0 | 90 | 90 | Cook Inlet | 27.2 |
| Killer whale | 6 | 6 | 12 | Eastern North Pacific Alaska Resident | 0.6 |
| | | | | Eastern North Pacific Gulf of Alaska, Aleutian Islands and Bering Sea Transient | 2.04 |
| Harbor porpoise | 16 | 8 | 24 | Gulf of Alaska | 0.08 |
| Steller sea lion | 6 | 3 | 9 | Western | 0.015 |
| Harbor seal | 99 | 55 | 154 | Cook Inlet/Shelikof Strait | 0.54 |
| NMFS conservatively assumes that all takes occur to each stock |
| NMFS does not have an official abundance estimate for this stock and the minimum population estimate is considered to be unknown (Young et al., 2023). See Small Numbers for additional discussion. |
| This abundance estimate is from Goetz et al. (2023); which was published after the most recent CIBW SAR (Young et al., 2023). |
Table 26—Proposed Shutdown Zones During Specified Activities
| Activity | Pile type/size | Attenuated or unattenuated | Shutdown zone (m) |
| LF cetaceans | Non-CIBW MF cetaceans | CIBWs | HF cetaceans | PW | OW |
| Vibratory Installation | 24-in | Unattenuated | 100 | 100 | 2,250 | 100 | 100 | 100 |
| | 36-in | | | | 4,520 | | | |
| | 72-in | | | | | | | |
| | 72-in | | | | 9,100 | | | |
| | 24-in | Attenuated | | | 2,630 | | | |
| | 36-in | | | | 3,580 | | | |
| | 72-in | | | | 6,120 | | | |
| Vibratory Removal | 24-in | Unattenuated | | | 5,970 | | | |
| | 36-in | | | | 1,700 | | | |
| | 24-in | Attenuated | | | 2,100 | | | |
| | 36-in | | | | 1,320 | | | |
| Impact Installation—1 pile per day | 24-in 36-in | Unattenuated | 500 | 500 | 1,600 | 500 | 100 | 100 |
| | 24-in 36-in | Attenuated | 100 | 100 | 550 | 100 | 100 | 100 |
| Impact Installation—1 pile per day | 72-in | Unattenuated | 500 | 500 | 7,360 | 500 | 100 | 100 |
| | | Attenuated | | | 2,520 | | | |
| Impact Installation—2 piles per day | | | | | | | | |
| Impact Installation—3 piles per day | | | | | | | | |
| Concurrent—2 Vibratory sources | 36-in AND 36-in | Attenuated/Attenuated Attenuated/Unattenuated Unattenuated/Unattenuated | 100 | 100 | 5,670 9,370 9,070 | 100 | 100 | 100 |
| | 36-in AND 72-in | Attenuated/Attenuated Unattenuated/Attenuated | | | 8,320 9,370 | | | |
| Concurrent Vibratory/Impact | 36-in AND 72-in | Attenuated/Attenuated (1 pile per day) Attenuated/Attenuated (2 piles per day) Attenuated/Attenuated (3 piles per day) | 500 | 500 | 3,580 | 500 | 100 | 100 |
| | | Unattenuated/Attenuated (1 pile per day) Unattenuated/Attenuated (2 piles per day) Unattenuated/Attenuated (3 piles per day) | | | 4,520 | | | |
| Notes: cm = centimeter(s), m = meter(s); POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to have larger ensonified areas, we have used these piles in our analyses of concurrent activities. |
| In the Updated Technical Guidance (NMFS, 2024), the MF Cetacean hearing group has been re-named the HF Cetacean group; HF Cetaceans from the 2018 Technical Guidance have been re-named VHF Cetaceans. |
