90 FR 107 pgs. 23891-23914 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the City of Whittier's Whittier Harbor Rebuild Phase III Project in Whittier, Alaska
Type: NOTICEVolume: 90Number: 107Pages: 23891 - 23914
Pages: 23891, 23892, 23893, 23894, 23895, 23896, 23897, 23898, 23899, 23900, 23901, 23902, 23903, 23904, 23905, 23906, 23907, 23908, 23909, 23910, 23911, 23912, 23913, 23914Docket number: [RTID 0648-XE898]
FR document: [FR Doc. 2025-10232 Filed 6-4-25; 8:45 am]
Agency: Commerce Department
Sub Agency: National Oceanic and Atmospheric Administration
Official PDF Version: PDF Version
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE898]
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the City of Whittier's Whittier Harbor Rebuild Phase III Project in Whittier, Alaska
AGENCY:
National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION:
Notice; proposed incidental harassment authorization; request for comments on proposed authorization and possible renewal.
SUMMARY:
NMFS has received a request from the City of Whittier for authorization to take marine mammals incidental to the Whittier Harbor Rebuild Phase III Project in Whittier, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
DATES:
Comments and information must be received no later than July 7, 2025.
ADDRESSES:
Comments should be addressed to the Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service and should be submitted via email to ITP.Potlock@noaa.gov. 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/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems accessing these documents, please call the contact listed below.
Instructions: NMFS is not responsible for comments sent by any other method, to any other address or individual, or received after the end of the comment period. Comments, including all attachments, must not exceed a 25-megabyte file size. All comments received are a part of the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying information ( e.g., name, address) voluntarily submitted by the commenter may be publicly accessible. Do not submit confidential business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT:
Kelsey Potlock, Office of Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
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 proposed or, if the taking is limited to harassment, a notice of a proposed IHA is provided to the public for review.
[top] 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). Further, 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
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 review our proposed action ( i.e., the issuance of an IHA) with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified in Categorical Exclusion B4 (IHAs with no anticipated serious injury or mortality) of the Companion Manual for NAO 216-6A, which do not individually or cumulatively have the potential for significant impacts on the quality of the human environment and for which we have not identified any extraordinary circumstances that would preclude this categorical exclusion. Accordingly, NMFS has preliminarily determined that the issuance of the proposed IHA qualifies to be categorically excluded from further NEPA review.
We will review all comments submitted in response to this notice prior to concluding our NEPA process or making a final decision on the IHA requests.
Summary of Request
On January 14, 2025, NMFS received a request from the City of Whittier (CoW) for an IHA to take marine mammals incidental to construction activities for the Whittier Harbor Rebuild Phase III Project in Whittier, Alaska. Following NMFS' review of the application, CoW submitted a revised version on March 18, 2025. The application was deemed adequate and complete on March 14, 2025. CoW's request is for take of killer whales ( Orcinus orca ), Dall's porpoise ( Phocoenoides dalli ), harbor seals ( Phoca vitulina ), and Steller sea lions ( Eumetopias jubatus ) by Level B harassment only. Neither CoW nor NMFS expect serious injury or mortality to result from this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
The CoW has requested an IHA to remove and subsequently install in-water structures and piles. The purpose of the project is to provide safe moorage for the boating public by removing and replacing all timber piles and three damaged floats in the highly trafficked Whittier Harbor. There have been two previous expansions (in 1980 and 2010) since the construction of the Harbor in 1972; however, the Harbor's slip waitlist is currently around 360 vessels long, which equates to a five to seven year waiting period. Several components that currently exist at the site (specifically float systems A, G, and H) consist of broken and rotted wood components well past the standard life expectancy of such structures. This proposed project is crucial to continue the operation of businesses and residents to the citizens of Whittier.
To date, Phases I and II have been completed (in the early 2000s (around 2008-2009)) and Phase III is necessary for the final improvements to the harbor. To complete Phase III of the Whitter Harbor Rebuild Project, three of the harbor's 11 float systems (consisting of 42 boat slips and their associated walkways, and water/fire systems) require pile driving via a vibratory hammer. Overall, CoW would need to remove 155 existing creosote-treated timber piles (12- to 16-inch (in; 30.5- to 40.6-centimeter (cm))), 10 existing steel piles (16-in (40.6-cm)), 3 walkway floats, and 42 float "fingers" ( i.e., a small floating pontoon or structure that both separates and provides access to berthed boats in a marina; they facilitate the transit of passengers to a berthed vessel) that make up the boat slips, and subsequently install 90 steel piles (16-in (40.6-cm)), 3 new walkway floats, and 42 new float "fingers".
Given the use of vibratory pile driving to both remove and install piles, there is potential for take of marine mammals, by Level B harassment only; no take by Level A harassment is expected or requested for this project.
Dates and Duration
CoW anticipates that this project would require up to 104 hours over 29 non-consecutive days during a 6 to 7 month period. Currently, construction activities are anticipated for fall 2025.
Specific Geographic Region
The proposed project would occur in the Whittier Harbor, located within the city limits of Whittier in southcentral Alaska (latitude: 60.77774, longitude: -148.6890). The Whittier Harbor is east of the Whittier cruise ship dock and Cliffside Marina and west of the ferry terminal. The construction work would occur nearshore behind the breakwater located at the project site (see figure 1).
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[Federal Register graphic "EN05JN25.000" is not available. Please view the graphic in the PDF version of this document.]
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Figure 1-CoW's Proposed Project Activities in Whittier, Alaska
Detailed Description of the Specified Activity
Within Whittier Harbor, 360 slips measuring 0 to 60-feet (ft) in length (0 to 18.3 meters (m)) for both commercial and recreational activities currently exist. The Harbor was constructed in 1972 and expanded twice (in 1980 and in 2010) but still retains an extensive waitlist for slips (approximately 360 vessels long), with a duration of five to seven years. The Harbor is utilized by a mix of commercial/business interests (primarily fishing charters and ocean cruises) as well as residents of Whittier. Furthermore, the Harbor also serves as a substantial revenue stream to the City of Whittier through moorage, other fees, and a vessel property tax for year-round moorage. This project is necessary because the existing timber piles throughout the Harbor have significantly aged and need to be replaced and the existing float system for A, G, and H floats also require replacement given advanced age. The issues with the Harbor's existing structures ( i.e., rotted wood, cracked surfacing, and holes) pose as safety risks for users in this highly trafficked area in Whittier.
[top] The Project is broken up into the Project Unit West and the Project Unit East (see figure 13 in the ITA application). Collectively across the Project, CoW has proposed to remove up to 155 existing 12- to 16-in (30.5- to 40.6-cm) creosote-treated timber piles, 10 existing 16-in (40.6-cm) steel piles, three walkway floats ( i.e., A, G, and H), and 42 float "fingers" which make up
For the activities, CoW would utilize several construction vessels, including:
• One 100-ft x 400-ft (30.5-m x 122-m) (or similar) supply barge carrying new replacement floats and piles;
• Two construction crane barges: one, approximately 41-ft x 148-ft (12.5-m x 45-m) barge to support areas accessible by it and to carry removed A, G, and H floats and timber piles;
• One, approximately 38-ft x 70-ft (1.6-m x 21.3-m), barge to support construction in confined spaces;
• One, approximately 25-ft x 26-ft (7.6-m x 7.9-m), tug to transport and maneuver project barges; and
• Two skiffs, transported to the project site by barge, to support construction and potentially marine mammal monitoring activities.
At Whittier, all barges would be secured with below-surface anchors. Upon demolition of the existing old structures, the larger construction barge would tow the removed timber piles and floats for A, G, and H to Valdez for disposal at the local landfill.
All construction is expected to begin in mid-September 2025 and continue through the spring of 2026. CoW estimates that all in-water pile-driving activities (removal and installation) are expected to occur for a total of 104 hours over 29 days, of which the days may not be consecutive as other activities occur between bouts of pile driving. Overall, the entire project is expected to occur over 6 to 7 months. This IHA, if issued, would authorize take incidental to the third (non-consecutive) year of work (2025-2026); the initial two projects (Phase I and II) were completed in the early 2000s (around 2008-2009).
All of the quantitative information found here can be found in table 1 below.
| Removal/installation parameters | Timber pile removal | Steel pile removal | Steel pile installation |
|---|---|---|---|
| Summary | |||
| Pile Diameter | 12-16 in (30-41 cm) | 16 in (41 cm) | 16 (41 cm) |
| Number of Piles | 155 | 10 | 90 |
| Installation/Removal Information | |||
| Maximum Number of Piles Per Day | 12 | 10 | 6 |
| Estimated Vibratory Time Per Pile (minutes) | 5 | 5 | 60 |
| Maximum Vibratory Time Per Day (minutes) | 60 | 50 | 360 |
| Total Duration Estimated (days)? a | 13 | 1 | 15 |
| Total Time Estimated (hours) | 13 | 1 | 90 |
| a ?Rounded to the nearest day. | |||
Proposed mitigation, monitoring, and reporting measures are described in detail later in this document (please see Proposed Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history of the potentially affected species. NMFS fully considered all of this information, and we refer the reader to these descriptions, instead of reprinting the information. Additional information regarding population trends and threats may be found in NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments ) and more general information about these species ( e.g., physical and behavioral descriptions) may be found on NMFS' website ( https://www.fisheries.noaa.gov/find-species).
Table 2 lists all species or stocks for which take is expected and proposed to be authorized for CoW's activities in Whittier and summarizes information related to the population or stock, including regulatory status under the MMPA and Endangered Species Act (ESA) and potential biological removal (PBR), where known. PBR is defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population (as described in NMFS' SARs). While no serious injury or mortality is anticipated or proposed to be authorized here, PBR and annual serious injury and mortality (M/SI) from anthropogenic sources are included here as gross indicators of the status of the species or stocks and other threats.
[top] Marine mammal abundance estimates presented in this document represent the total number of individuals that make up a given stock or the total number estimated within a particular study or survey area. NMFS' stock abundance estimates for most species represent the total estimate of individuals within the geographic area, if known, that comprises that stock. For some species, this geographic area may extend beyond U.S. waters. All managed stocks in this region are assessed in NMFS' draft 2024 Alaska and Pacific SARs. All values presented in table 2 are the most recent available at the time of publication (including from the draft 2024 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
| Common name | Scientific name | Stock | ESA/MMPA status; strategic (Y/N)? b | Stock abundance (CV; N min ; most recent abundance survey)? c | PBR | Annual M/SI? d |
|---|---|---|---|---|---|---|
| Order Artiodactyla-Cetacea-Superfamily Odontoceti (toothed whales, dolphins, and porpoises) | ||||||
| Family Delphinidae: | ||||||
| Killer whale | Orcinus orca | Alaska Resident | -, -, N | 1,920 (N/A, 1,920, 2019)? e | 18 | 1.3 |
| Gulf of Alaska/Aleutian Islands/Bering Sea Transient | -, -, N | 587 (N/A, 587, 2012)? f | 5.9 | 0.8 | ||
| Family Phocoenidae (porpoises): | ||||||
| Dall's porpoise | Phocoenoides dalli | Alaska | -, -, N | UND (UND, UND, 2015)? g | UND | 37 |
| Order Carnivora-Pinnipedia | ||||||
| Family Otariidae (eared seals and sea lions): | ||||||
| Steller sea lion | Eumetopias jubatus | Western | E, D, Y | 49,837 (N/A, 49,837, 2022)? h | 299 | 267 |
| Family Phocidae (earless seals): | ||||||
| Harbor seal | Phoca vitulina | Prince William Sound | -, -, N | 44,756 (N/A, 41,776, 2015) | 1,253 | 413 |
| a ?Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy ( https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy, 2024). | ||||||
| b ?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. | ||||||
| c ?NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; N min is the minimum estimate of stock abundance. In some cases, CV is not applicable. | ||||||
| d ?These values, found in NMFS' 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. A CV associated with estimated mortality due to commercial fisheries is presented in some cases. | ||||||
| e ?N est is based upon counts of individuals identified from photo-ID catalogs. | ||||||
| f ?N est is based upon counts of individuals identified from photo-ID catalogs. | ||||||
| g ?The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small portion of the stock's range. | ||||||
| h ?N est is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the United States only. The overall N min is 73,211 and overall PBR is 439. | ||||||
As indicated above in table 2, all four species (with five managed stocks) temporally and spatially co-occur with the activity to the degree that take is reasonably likely to occur. All species that could potentially occur in the proposed project areas are included in section 4 and table 5 of CoW's IHA application. For humpback whales ( Megaptera novaeangliae), the inland waters of Southeast Alaska are a seasonal feeding biologically important area (BIA) from May through September (Wild et al., 2023). However, the applicant has requested no take of this species given they would shut down/delay any pile driving activities in the event that a humpback whale is observed at the edge of the Level B harassment isopleth. Because of this, no take is expected to occur given the enhanced mitigation measures. Furthermore, Whittier Harbor is located in a small passageway of the Prince William Sound area, and represents a tiny portion of the available habitat for humpback whales. The AT1 Transient stock of killer whales (consisting of seven individuals) has been reported in the area of Whittier, but the likelihood of this stock occurring in the project area during the short proposed project timeframe (29 days) during active pile driving is low, and no take of this stock is proposed for authorization. Therefore, they are not discussed further in this notice. In addition, sea otters ( Enhydra lutris ) may be found in both the Prince William Sound and Whittier, Alaska. However, this species is managed by the U.S. Fish and Wildlife Service (see https://www.fws.gov/species/sea-otter-enhydra-lutris ) and therefore not discussed further in this document.
For more details on the species that are likely to occur near the project area and may be taken by CoW's proposed activities, see CoW's IHA application, the draft SARs, and NMFS' website.
Marine Mammal Hearing
[top] Hearing is the most important sensory modality for marine mammals underwater, and exposure to anthropogenic sound can have deleterious effects. To appropriately assess the potential effects of exposure to sound, it is necessary to understand the frequency ranges marine mammals can hear. Not all marine mammal species have equal hearing capabilities ( e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. (2007, 2019) recommended that marine mammals be divided into hearing groups based on directly measured (behavioral or auditory evoked potential techniques) or estimated hearing ranges (behavioral response data, anatomical modeling, etc. ). Generalized hearing ranges were chosen based on the ~65 decibel (dB) threshold from composite audiograms, previous analyses in NMFS (2024), and/or data from Southall et al. (2007) and Southall et al. (2019). We note that the names of two hearing groups and the generalized hearing ranges of all marine mammal hearing groups have been recently updated (NMFS, 2024), as reflected below in table 3. Of the species that could be potentially taken in the proposed project area, none are considered low-frequency (LF) cetaceans, one is considered a high-frequency (HF) cetacean, one is considered a very high-frequency (VHF) cetacean, one is an otariid pinniped, and one is a phocid pinniped.
| Hearing group | Generalized hearing range?* |
|---|---|
| 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. |
| *?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) and Southall et al. (2019). Additionally, animals are able to detect very loud sounds above and below that "generalized" hearing range. Hz = Hertz; kHz = kilohertz. | |
For more detail concerning these groups and associated generalized hearing ranges, please see (NMFS, 2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their Habitat
This section includes a summary and provides a discussion of the ways in which components of the specified activity may impact marine mammals and their habitat. The Estimated Take of Marine Mammals section later in this document includes a quantitative analysis of the number of individuals that are expected to be taken by this activity. The Negligible Impact Analysis and Determination section considers the content of this section, the Estimated Take of Marine Mammals section, and the Proposed Mitigation section, to draw conclusions regarding the likely impacts of these activities on the reproductive success or survivorship of individuals and whether those impacts are reasonably expected to, or reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activities are expected to potentially occur from vibratory pile removal and installation. The effects of underwater noise from CoW's proposed activities have the potential to result in take by Level B harassment of marine mammals in the project area.
Overall, the proposed activities would result in the removal of 165 piles (155 timber and 10 steel) by vibratory pile driving, 3 walkway floats, and 42 float "fingers". CoW would then install 90 steel piles by vibratory pile driving, 3 new walkway floats, and 42 float "fingers" in Whittier Harbor. There are a variety of types and degrees of effects to marine mammals, prey species, and habitat that could occur because of the proposed project. Below we provide a brief description of the types of sound sources that would be generated by the project, the general impacts from these types of activities, and an analysis of the anticipated impacts on marine mammals from the project, with consideration of the proposed mitigation measures.
Description of Sound Sources for the Specified Activities
Activities associated with the proposed project that have the potential to incidentally take marine mammals though exposure to sound would include vibratory pile removal and installation. Vibratory hammers install piles by vibrating them and allowing the weight of the hammer to push them into the substrate. Vibratory hammers typically produce less sound ( i.e., lower levels) than impact hammers. Peak sound pressure levels (SPLs) may be 180 dB or greater, but are generally 10 to 20 dB lower than SPLs generated during impact pile driving of the same-sized pile (Oestman et al., 2009; California Department of Transportation (CALTRANS; 2015, 2020). Sounds produced by vibratory hammers are non-impulsive; compared to sounds produced by impact hammers, the rise time is slower, reducing the probability and severity of injury, and the sound energy is distributed over a greater amount of time (Nedwell and Edwards, 2002; Carlson et al., 2005).
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic environment from vibratory pile driving is the primary means by which marine mammals may be harassed from CoW's specified activities. Anthropogenic sounds cover a broad range of frequencies and sound levels and can have a range of highly variable impacts on marine life from none or minor to potentially severe responses depending on received levels, duration of exposure, behavioral context, and various other factors. Broadly, underwater sound from active acoustic sources, such as those in the Project, can potentially result in one or more of the following: temporary or permanent hearing impairment, non-auditory physical or physiological effects, behavioral disturbance, stress, and masking (Richardson et al., 1995; Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007; Götz et al., 2009).
We describe the more severe effects of certain non-auditory physical or physiological effects only briefly as we do not expect that use of the vibratory hammer is reasonably likely to result in such effects (see below for further discussion). Potential effects from impulsive sound sources can range in severity from effects such as behavioral disturbance or tactile perception to physical discomfort, slight injury of the internal organs and the auditory system, or mortality (Yelverton et al., 1973). Non-auditory physiological effects or injuries that theoretically might occur in marine mammals exposed to high level underwater sound or as a secondary effect of extreme behavioral reactions ( e.g., change in dive profile as a result of an avoidance reaction) caused by exposure to sound include neurological effects, bubble formation, resonance effects, and other types of organ or tissue damage (Cox et al., 2006; Southall et al., 2007; Zimmer and Tyack, 2007; Tal et al., 2015). The project activities considered here do not involve the use of devices such as explosives or mid-frequency tactical sonar that are associated with these types of effects.
[top] In general, animals exposed to natural or anthropogenic sound may experience physical and psychological effects, ranging in magnitude from none to severe (Southall et al., 2007, 2019). Exposure to anthropogenic noise has the potential to result in auditory threshold shifts and behavioral reactions ( e.g., avoidance, temporary cessation of foraging and vocalizing, changes in dive behavior). It can also lead to non-observable physiological responses,
The degree of effect of an acoustic exposure on marine mammals is dependent on several factors, including, but not limited to, sound type ( e.g., impulsive vs. non-impulsive), signal characteristics, the species, age and sex class ( e.g., adult male vs. mom with calf), duration of exposure, the distance between the noise source and the animal, received levels, behavioral state at time of exposure, and previous history with exposure (Wartzok et al., 2004; Southall et al., 2007). In general, sudden, high-intensity sounds can cause hearing loss, as can longer exposures to lower-intensity sounds. Moreover, any temporary or permanent loss of hearing, if it occurs at all, will occur almost exclusively for noise within an animal's hearing range. We describe below the specific manifestations of acoustic effects that may occur based on the activities proposed by CoW.
Richardson et al. (1995) described zones of increasing intensity of effect that might be expected to occur in relation to distance from a source and assuming that the signal is within an animal's hearing range. First (at the greatest distance) is the area within which the acoustic signal would be audible (potentially perceived) to the animal but not strong enough to elicit any overt behavioral or physiological response. The next zone (closer to the receiving animal) corresponds with the area where the signal is audible to the animal and of sufficient intensity to elicit behavioral or physiological responsiveness. The third is a zone within which, for signals of high intensity, the received level is sufficient to potentially cause discomfort or tissue damage to auditory or other systems. Overlaying these zones to a certain extent is the area within which masking ( i.e., when a sound interferes with or masks the ability of an animal to detect a signal of interest that is above the absolute hearing threshold) may occur; the masking zone may be highly variable in size.
Below, we provide additional detail regarding potential impacts on marine mammals and their habitat from noise in general, starting with hearing impairment, as well as from the specific activities CoW plans to conduct, to the degree it is available.
Hearing Threshold Shifts. NMFS defines a noise-induced threshold shift (TS) as a change, usually an increase, in the threshold of audibility at a specified frequency or portion of an individual's hearing range above a previously established reference level (NMFS, 2018, 2024). The amount of threshold shift is customarily expressed in dB. TS can be permanent or temporary. As described in NMFS (2018, 2024) there are numerous factors to consider when examining the consequence of TS, including, but not limited to, the signal temporal pattern ( e.g., impulsive or non-impulsive), likelihood an individual would be exposed for a long enough duration or to a high enough level to induce a TS, the magnitude of the TS, time to recovery (seconds to minutes, or hours to days), the frequency range of the exposure ( i.e., spectral content), the hearing frequency range of the exposed species relative to the signal's frequency spectrum ( i.e., how animal uses sound within the frequency band of the signal; e.g., Kastelein et al., 2014), and the overlap between the animal and the source ( e.g., spatial, temporal, and spectral).
Auditory Injury (AUD INJ). NMFS (2024) defines AUD INJ as damage to the inner ear that can result in destruction of tissue, such as the loss of cochlear neuron synapses or auditory neuropathy (Houser, 2021; Finneran, 2024). AUD INJ may or may not result in a permanent threshold shift (PTS). PTS is subsequently defined as a permanent, irreversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range above a previously established reference level (NMFS, 2024). PTS does not generally affect more than a limited frequency range, and an animal that has incurred PTS has some level of hearing loss at the relevant frequencies; typically animals with PTS or other AUD INJ are not functionally deaf (Au and Hastings, 2008; Finneran, 2016). Available data from humans and other terrestrial mammals indicate that a 40-dB threshold shift approximates AUD INJ onset (see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson et al., 2008). AUD INJ levels for marine mammals are estimates, as with the exception of a single study unintentionally inducing PTS in a harbor seal ( Phoca vitulina ) (Kastak et al., 2008), there are no empirical data measuring AUD INJ in marine mammals largely due to the fact that, for various ethical reasons, experiments involving anthropogenic noise exposure at levels inducing AUD INJ are not typically pursued or authorized (NMFS, 2024).
Temporary Threshold Shift (TTS). TTS is a temporary, reversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range above a previously established reference level (NMFS, 2024), and is not considered an AUD INJ. Based on data from marine mammal TTS measurements (see Southall et al., 2007, 2019), a TTS of 6 dB is considered the minimum threshold shift clearly larger than any day-to-day or session-to-session variation in a subject's normal hearing ability (Finneran et al., 2000, 2002; Schlundt et al., 2000). As described in Finneran (2015), marine mammal studies have shown the amount of TTS increases with the 24-hour cumulative sound exposure level (SEL 24 ) in an accelerating fashion: at low exposures with lower SEL 24 , the amount of TTS is typically small and the growth curves have shallow slopes. At exposures with higher SEL 24 , the growth curves become steeper and approach linear relationships with the sound exposure level (SEL).
Depending on the degree (elevation of threshold in dB), duration ( i.e., recovery time), and frequency range of TTS, and the context in which it is experienced, TTS can have effects on marine mammals ranging from discountable to more impactful (similar to those discussed in auditory masking, below). For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that takes place during a time when the animal is traveling through the open ocean, where ambient noise is lower and there are not as many competing sounds present. Alternatively, a larger amount and longer duration of TTS sustained during time when communication is critical for successful mother/calf interactions could have more severe impacts. We note that reduced hearing sensitivity as a simple function of aging has been observed in marine mammals, as well as humans and other taxa (Southall et al., 2007), so we can infer that strategies exist for coping with this condition to some degree, though likely not without cost.
[top] Many studies have examined noise-induced hearing loss in marine mammals (see Finneran (2015) and Southall et al. (2019) for summaries). TTS is the mildest form of hearing impairment that can occur during exposure to sound (Kryter, 2013). While experiencing TTS, the hearing threshold rises, and a sound must be at a higher level in order to be heard. In terrestrial and marine mammals, TTS can last from minutes or hours to days (in cases of strong TTS). In many cases, hearing sensitivity recovers rapidly after exposure to the sound ends. For cetaceans, published data on the onset
The amount and onset of TTS depends on the exposure frequency. Sounds below the region of best sensitivity for a species or hearing group are less hazardous than those near the region of best sensitivity (Finneran and Schlundt, 2013). At low frequencies, onset-TTS exposure levels are higher compared to those in the region of best sensitivity ( e.g., a low frequency noise would need to be louder to cause TTS onset when TTS exposure level is higher), as shown for harbor porpoises and harbor seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor seals and harbor porpoises have a lower TTS onset than other measured pinniped or cetacean species (Finneran, 2015). In addition, TTS can accumulate across multiple exposures, but the resulting TTS will be less than the TTS from a single, continuous exposure with the same SEL (Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014, 2015). This means that TTS predictions based on the total, SEL 24 will overestimate the amount of TTS from intermittent exposures, such as sonars and impulsive sources. Nachtigall et al. (2018) describe measurements of hearing sensitivity of multiple odontocete species (bottlenose dolphin, harbor porpoise, beluga ( Delphinapterus leucas ), and false killer whale ( Pseudorca crassidens )) when a relatively loud sound was preceded by a warning sound. These captive animals were shown to reduce hearing sensitivity when warned of an impending intense sound. Based on these experimental observations of captive animals, the authors suggest that wild animals may dampen their hearing during prolonged exposures or if conditioned to anticipate intense sounds. Another study showed that echolocating animals (including odontocetes) might have anatomical specializations that might allow for conditioned hearing reduction and filtering of low-frequency ambient noise, including increased stiffness and control of middle ear structures and placement of inner ear structures (Ketten et al., 2021). Data available on noise-induced hearing loss for mysticetes are currently lacking (NMFS, 2024). Additionally, the existing marine mammal TTS data come from a limited number of individuals within these species.
Relationships between TTS and AUD INJ thresholds have not been studied in marine mammals, and there are no measured PTS data for cetaceans, but such relationships are assumed to be similar to those in humans and other terrestrial mammals. AUD INJ typically occurs at exposure levels at least several dB above that inducing mild TTS ( e.g., a 40-dB threshold shift approximates AUD INJ onset (Kryter et al., 1966; Miller, 1974), while a 6-dB threshold shift approximates TTS onset (Southall et al., 2007, 2019). Based on data from terrestrial mammals, a precautionary assumption is that the AUD INJ thresholds for impulsive sounds (such as impact pile driving pulses as received close to the source) are at least 6 dB higher than the TTS threshold on a peak-pressure basis and AUD INJ cumulative sound exposure level thresholds are 15 to 20 dB higher than TTS cumulative sound exposure level thresholds (Southall et al., 2007, 2019). Given the higher level of sound or longer exposure duration necessary to cause AUD INJ as compared with TTS, it is considerably less likely that AUD INJ could occur.
Behavioral Effects. Exposure to noise also has the potential to behaviorally disturb marine mammals to a level that rises to the definition of harassment under the MMPA. Generally speaking, NMFS considers a behavioral disturbance that rises to the level of harassment under the MMPA a non-minor response-in other words, not every response qualifies as behavioral disturbance, and for responses that do, those of a higher level, or accrued across a longer duration, have the potential to affect foraging, reproduction, or survival. Behavioral disturbance may include a variety of effects, including subtle changes in behavior ( e.g., minor or brief avoidance of an area or changes in vocalizations), more conspicuous changes in similar behavioral activities, and more sustained and/or potentially severe reactions, such as displacement from or abandonment of high-quality habitat. Behavioral responses may include changing durations of surfacing and dives, changing direction and/or speed; reducing/increasing vocal activities; changing/cessation of certain behavioral activities (such as socializing or feeding); eliciting a visible startle response or aggressive behavior (such as tail/fin slapping or jaw clapping); and avoidance of areas where sound sources are located. In addition, pinnipeds may increase their haul out time, possibly to avoid in-water disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-specific and any reactions depend on numerous intrinsic and extrinsic factors ( e.g., species, state of maturity, experience, current activity, reproductive state, auditory sensitivity, time of day), as well as the interplay between factors ( e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not only among individuals but also within an individual, depending on previous experience with a sound source, context, and numerous other factors (Ellison et al., 2012), and can vary depending on characteristics associated with the sound source ( e.g., whether it is moving or stationary, number of sources, distance from the source). In general, pinnipeds seem more tolerant of, or at least habituate more quickly to, potentially disturbing underwater sound than do cetaceans, and generally seem to be less responsive to exposure to industrial sound than most cetaceans. Please see Appendices B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews of studies involving marine mammal behavioral responses to sound.
[top] Habituation can occur when an animal's response to a stimulus wanes with repeated exposure, usually in the absence of unpleasant associated events (Wartzok et al., 2004). Animals are most likely to habituate to sounds that are predictable and unvarying. It is important to note that habituation is appropriately considered as a "progressive reduction in response to stimuli that are perceived as neither aversive nor beneficial," rather than as, more generally, moderation in response to human disturbance (Bejder et al., 2009). The opposite process is sensitization, when an unpleasant experience leads to subsequent
As noted above, behavioral state may affect the type of response. For example, animals that are resting may show greater behavioral change in response to disturbing sound levels than animals that are highly motivated to remain in an area for feeding (Richardson et al., 1995; Wartzok et al., 2004; National Research Council (NRC), 2005). Controlled experiments with captive marine mammals have shown pronounced behavioral reactions, including avoidance of loud sound sources (Ridgway et al., 1997; Finneran et al., 2003). Observed responses of wild marine mammals to loud-pulsed sound sources ( e.g., seismic airguns) have been varied but often consist of avoidance behavior or other behavioral changes (Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater sound; therefore, it is difficult to predict specifically how any given sound in a particular instance might affect marine mammals perceiving the signal ( e.g., Erbe et al., 2019). If a marine mammal does react briefly to an underwater sound by changing its behavior or moving a small distance, the impacts of the change are unlikely to be significant to the individual, let alone the stock or population. If a sound source displaces marine mammals from an important feeding or breeding area for a prolonged period, impacts on individuals and populations could be significant ( e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 2005). However, there are broad categories of potential response, which we describe in greater detail here, that include alteration of dive behavior, alteration of foraging behavior, effects to breathing, interference with or alteration of vocalization, avoidance, and flight.
Avoidance and displacement. Changes in dive behavior can vary widely and may consist of increased or decreased dive times and surface intervals as well as changes in the rates of ascent and descent during a dive ( e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013a, 2013b; Blair et al., 2016). Variations in dive behavior may reflect interruptions in biologically significant activities ( e.g., foraging) or they may be of little biological significance. The impact of an alteration to dive behavior resulting from an acoustic exposure depends on what the animal is doing at the time of the exposure and the type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with anthropogenic sound exposure, so it is usually inferred by observed displacement from known foraging areas, the appearance of secondary indicators ( e.g., bubble nets or sediment plumes), or changes in dive behavior. Acoustic and movement bio-logging tools also have been used in some cases to infer responses to anthropogenic noise. For example, Blair et al. (2015) reported significant effects on humpback whale foraging behavior in Stellwagen Bank in response to ship noise including slower descent rates, and fewer side-rolling events per dive with increasing ship nose. In addition, Wisniewska et al. (2018) reported that tagged harbor porpoises demonstrated fewer prey capture attempts when encountering occasional high-noise levels resulting from vessel noise as well as more vigorous fluking, interrupted foraging, and cessation of echolocation signals observed in response to some high-noise vessel passes. As for other types of behavioral response, the frequency, duration, and temporal pattern of signal presentation, as well as differences in species sensitivity, are likely contributing factors to differences in response in any given circumstance ( e.g., Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 2007). A determination of whether foraging disruptions incur fitness consequences would require information on or estimates of the energetic requirements of the affected individuals and the relationship between prey availability, foraging effort and success, and the life history stage of the animal.
Respiration rates vary naturally with different behaviors, and alterations to breathing rate as a function of acoustic exposure can be expected to co-occur with other behavioral reactions, such as a flight response or an alteration in diving. However, respiration rates in and of themselves may be representative of annoyance or an acute stress response. Various studies have shown that respiration rates may either be unaffected or could increase, depending on the species and signal characteristics, again highlighting the importance in understanding species differences in the tolerance of underwater noise when determining the potential for impacts resulting from anthropogenic sound exposure ( e.g., Kastelein et al., 2001; 2005; 2006; Gailey et al., 2007). For example, harbor porpoise respiration rates increased in response to pile driving sounds at and above a received broadband SPL of 136 dB (zero-peak SPL: 151 dB micropascal (re 1 µPa); SEL of a single strike (SEL ss ): 127 dB re 1 square micropascals per second (µPa 2 -s; Kastelein et al., 2013).
Avoidance is the displacement of an individual from an area or migration path because of the presence of a sound or other stressors, and is one of the most obvious manifestations of disturbance in marine mammals (Richardson et al., 1995). For example, gray whales are known to change direction-deflecting from customary migratory paths-in order to avoid noise from seismic surveys (Malme et al., 1984). Harbor porpoises, Atlantic white-sided dolphins ( Lagenorhynchus actusus ), and minke whales ( Balaenoptera acutorostrata ) have demonstrated avoidance in response to vessels during line transect surveys (Palka and Hammond, 2001). In addition, beluga whales in the St. Lawrence Estuary in Canada have been reported to increase levels of avoidance with increased boat presence by way of increased dive durations and swim speeds, decreased surfacing intervals, and by bunching together into groups (Blane and Jaakson, 1994). Avoidance may be short-term, with animals returning to the area once the noise has ceased ( e.g., Bowles et al., 1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). Longer-term displacement is possible, however, which may lead to changes in abundance or distribution patterns of the affected species in the affected region if habituation to the presence of the sound does not occur ( e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a directed and rapid movement away from the perceived location of a sound source. The flight response differs from other avoidance responses in the intensity of the response ( e.g., directed movement, rate of travel). Relatively little information on flight responses of marine mammals to anthropogenic signals exist, although observations of flight responses to the presence of predators have occurred (Connor and Heithaus, 1996; Bowers et al., 2018). The result of a flight response could range from brief, temporary exertion and displacement from the area where the signal provokes flight to, in extreme cases, marine mammal strandings (England et al., 2001). However, it should be noted that response to a perceived predator does not necessarily invoke flight (Ford and Reeves, 2008), and whether individuals are solitary or in groups may influence the response.
[top] Behavioral disturbance can also impact marine mammals in more subtle ways. Increased vigilance may result in costs related to diversion of focus and
Many animals perform vital functions, such as feeding, resting, traveling, and socializing, on a diel cycle (24-hour cycle). Disruption of such functions resulting from reactions to stressors such as sound exposure are more likely to be significant if they last more than one diel cycle or recur on subsequent days (Southall et al., 2007). Consequently, a behavioral response lasting less than one day and not recurring on subsequent days is not considered particularly severe unless it could directly affect reproduction or survival (Southall et al., 2007). Note that there is a difference between multi-day substantive ( i.e., meaningful) behavioral reactions and multi-day anthropogenic activities. For example, just because an activity lasts for multiple days does not necessarily mean that individual animals are either exposed to activity-related stressors for multiple days or, further, exposed in a manner resulting in sustained multi-day substantive behavioral responses.
Physiological stress responses. An animal's perception of a threat may be sufficient to trigger stress responses consisting of some combination of behavioral responses, autonomic nervous system responses, neuroendocrine responses, or immune responses ( e.g., Selye, 1950; Moberg, 2000). In many cases, an animal's first and sometimes most economical (in terms of energetic costs) response is behavioral avoidance of the potential stressor. Autonomic nervous system responses to stress typically involve changes in heart rate, blood pressure, and gastrointestinal activity. These responses have a relatively short duration and may or may not have a significant long-term effect on an animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine functions that are affected by stress-including immune competence, reproduction, metabolism, and behavior-are regulated by pituitary hormones. Stress-induced changes in the secretion of pituitary hormones have been implicated in failed reproduction, altered metabolism, reduced immune competence, and behavioral disturbance ( e.g., Moberg, 1987; Blecha, 2000). Increases in the circulation of glucocorticoids are also equated with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does not normally place an animal at risk) and "distress" is the cost of the response. During a stress response, an animal uses glycogen stores that can be quickly replenished once the stress is alleviated. In such circumstances, the cost of the stress response would not pose serious fitness consequences. However, when an animal does not have sufficient energy reserves to satisfy the energetic costs of a stress response, energy resources must be diverted from other functions. This state of distress will last until the animal replenishes its energetic reserves sufficient to restore normal function.
Relationships between these physiological mechanisms, animal behavior, and the costs of stress responses are well studied through controlled experiments and for both laboratory and free-ranging animals ( e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; Lankford et al., 2005; Ayres et al., 2012; Yang et al., 2022). Stress responses due to exposure to anthropogenic sounds or other stressors and their effects on marine mammals have also been reviewed (Fair and Becker, 2000; Romano et al., 2002b) and, more rarely, studied in wild populations ( e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found that noise reduction from reduced ship traffic in the Bay of Fundy was associated with decreased stress in North Atlantic right whales ( Eubalaena glacialis ). In addition, Lemos et al. (2022) observed a correlation between higher levels of fecal glucocorticoid metabolite concentrations (indicative of a stress response) and vessel traffic in gray whales. Yang et al. (2022) studied behavioral and physiological responses in captive bottlenose dolphins exposed to playbacks of "pile-driving-like" impulsive sounds, finding significant changes in cortisol and other physiological indicators but only minor behavioral changes. These and other studies lead to a reasonable expectation that some marine mammals will experience physiological stress responses upon exposure to acoustic stressors and that it is possible that some of these would be classified as "distress." In addition, any animal experiencing TTS would likely also experience stress responses (NRC, 2005), however distress is an unlikely result of this project based on observations of marine mammals during previous, similar construction projects.
Vocalizations and Auditory Masking. Since many marine mammals rely on sound to find prey, moderate social interactions, and facilitate mating (Tyack, 2008), noise from anthropogenic sound sources can interfere with these functions, but only if the noise spectrum overlaps with the hearing sensitivity of the receiving marine mammal (Southall et al., 2007; Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive, though not high-intensity, noise could cause masking at particular frequencies for marine mammals that utilize sound for vital biological functions (Clark et al., 2009). Acoustic masking is when other noises such as from human sources interfere with an animal's ability to detect, recognize, or discriminate between acoustic signals of interest ( e.g., those used for intraspecific communication and social interactions, prey detection, predator avoidance, navigation) (Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain circumstances, marine mammals whose acoustical sensors or environments are being severely masked could also be impaired from maximizing their performance fitness in survival and reproduction. The ability of a noise source to mask biologically important sounds depends on the characteristics of both the noise source and the signal of interest ( e.g., signal-to-noise ratio, temporal variability, direction), in relation to each other and to an animal's hearing abilities ( e.g., sensitivity, frequency range, critical ratios, frequency discrimination, directional discrimination, age or TTS hearing loss), and existing ambient noise and propagation conditions (Hotchkin and Parks, 2013).
[top] Marine mammals vocalize for different purposes and across multiple modes, such as whistling, echolocation click production, calling, and singing. Changes in vocalization behavior in response to anthropogenic noise can occur for any of these modes and may result from a need to compete with an increase in background noise or may reflect increased vigilance or a startle
Under certain circumstances, marine mammals experiencing significant masking could also be impaired from maximizing their performance fitness in survival and reproduction. Therefore, when the coincident (masking) sound is human-made, it may be considered harassment when disrupting or altering critical behaviors. It is important to distinguish TTS and PTS, which persist after the sound exposure, from masking, which occurs during the sound exposure. Because masking (without resulting in TS) is not associated with abnormal physiological function, it is not considered a physiological effect, but rather a potential behavioral effect (though not necessarily one that would be associated with harassment).
The frequency range of the potentially masking sound is important in determining any potential behavioral impacts. For example, low-frequency signals may have less effect on high-frequency echolocation sounds produced by odontocetes but are more likely to affect detection of mysticete communication calls and other potentially important natural sounds such as those produced by surf and some prey species. The masking of communication signals by anthropogenic noise may be considered as a reduction in the communication space of animals ( e.g., Clark et al., 2009) and may result in energetic or other costs as animals change their vocalization behavior ( e.g., Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt et al., 2009). Masking can be reduced in situations where the signal and noise come from different directions (Richardson et al., 1995), through amplitude modulation of the signal, or through other compensatory behaviors, including modifications of the acoustic properties of the signal or the signaling behavior (Hotchkin and Parks, 2013). Masking can be tested directly in captive species ( e.g., Erbe, 2008), but in wild populations it must be either modeled or inferred from evidence of masking compensation. There are few studies addressing real-world masking sounds likely to be experienced by marine mammals in the wild ( e.g., Branstetter et al., 2013).
Since noises generated from the proposed construction activities are mostly concentrated at low frequencies (<2 kHz), these activities likely have less effect on mid-frequency echolocation sounds produced by odontocetes (toothed whales). However, lower frequency noises are more likely to affect detection of communication calls and other potentially important natural sounds such as surf and prey noise. Low-frequency noise may also affect communication signals when they occur near the frequency band for noise and thus reduce the communication space of animals ( e.g., Clark et al., 2009) and cause increased stress levels ( e.g., Holt et al., 2009). Unlike TS, masking, which can occur over large temporal and spatial scales, can potentially affect the species at population, community, or even ecosystem levels, in addition to individual levels. Masking affects both senders and receivers of the signals, and at higher levels for longer durations, could have long-term chronic effects on marine mammal species and populations. However, the noise generated by CoW's proposed activities will only occur intermittently, across an estimated 46 days during the proposed authorization period in a relatively small area focused around the proposed construction site. Thus, while CoW's proposed activities may mask some acoustic signals that are relevant to the daily behavior of marine mammals, the short-term duration and limited areas affected make it very unlikely that the fitness of individual marine mammals would be impacted.
While in some cases marine mammals have exhibited little to no obviously detectable response to certain common or routine industrialized activities (Cornick et al., 2011; Horley and Larson, 2023), it is possible some animals may at times be exposed to received levels of sound above the Level B harassment thresholds during the proposed project. This potential exposure in combination with the nature of planned activity ( e.g., vibratory pile driving) means it is possible that take by Level B harassment could occur over the total estimated period of activities; therefore, NMFS, in response to the CoW's IHA application, proposes to authorize take by Level B harassment from the CoW's proposed construction activities.
Airborne Acoustic Effects. Pinnipeds that occur near the project site could be exposed to airborne sounds associated with construction activities that have the potential to cause behavioral harassment, depending on their distance from these activities. Airborne noise would primarily be an issue for pinnipeds that are swimming or hauled out near the project site within the range of noise levels elevated above airborne acoustic harassment criteria. Within the project area, no haul-out areas are known. Cetaceans are not expected to be exposed to airborne sounds that would result in harassment as defined under the MMPA.
We recognize that pinnipeds in the water could be exposed to airborne sound that may result in behavioral harassment when looking with their heads above water. Most likely, any airborne sound would cause behavioral responses similar to those discussed above in relation to underwater sound. For instance, anthropogenic sound could cause hauled out pinnipeds (if any are opportunistically present) to exhibit changes in their normal behavior, such as reduction in vocalizations, or cause them to flush from haul-outs, temporarily abandon the area, and or move further from the source. However, these animals would previously have been `taken' because of exposure to underwater sound above the behavioral harassment thresholds, which are in all cases larger than those associated with airborne sound. Thus, the behavioral harassment of these animals is already accounted for in these estimates of potential take. Therefore, we do not believe that authorization of incidental take resulting from airborne sound for pinnipeds is warranted, and airborne sound is not discussed further here.
Potential Effects on Marine Mammal Habitat
[top] CoW's proposed activities could have localized, temporary impacts on marine mammal habitat, including prey, by increasing in-water SPLs. Increased noise levels may affect acoustic habitat and adversely affect marine mammal prey near the project area (see
The total area likely impacted by CoW's activities is relatively small compared to the available habitat in and around Whittier Harbor. Avoidance by potential prey ( i.e., fish) of the immediate area due to increased noise is possible. The duration of fish and marine mammal avoidance of this area after pile driving stops is unknown, but a rapid return to normal recruitment, distribution, and behavior is anticipated. Any behavioral avoidance by fish or marine mammals of the disturbed area would still leave significantly large areas of fish and marine mammal foraging habitat in the nearby vicinity.
The proposed project will occur within the approximate footprint of existing marine infrastructure. The nearshore and intertidal habitat where the proposed project will occur is an area of relatively high marine vessel traffic. Most marine mammals do not generally use the area within the footprint of the project area. Temporary, intermittent, and short-term habitat alteration may result from increased noise levels during the proposed construction activities. Effects on marine mammals will be limited to temporary displacement from pile installation and removal noise, and effects on prey species will be similarly limited in time and space.
Water quality. Temporary and localized reduction in water quality will occur because of in-water construction activities. Most of this effect would occur during the installation and removal of piles when bottom sediments are disturbed. The installation and removal of piles using the vibratory hammer would disturb bottom sediments and may cause a temporary increase in suspended sediment in the project area. During pile extraction, sediment attached to the pile moves vertically through the water column until gravitational forces cause it to slough off under its own weight. The small resulting sediment plume is expected to settle out of the water column within a few hours. Studies of the effects of turbid water on fish (marine mammal prey) suggest that concentrations of suspended sediment can reach thousands of milligrams per liter before an acute toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-term, minor, and localized. Following the completion of sediment-disturbing activities, suspended sediments in the water column should dissipate and quickly return to background levels in all construction scenarios. Turbidity within the water column has the potential to reduce the level of oxygen in the water and irritate the gills of prey fish species in the proposed project area. However, turbidity plumes associated with the project would be temporary and localized, and fish in the proposed project area would be able to move away from and avoid the areas where plumes may occur. Therefore, it is expected that the impacts on prey fish species from turbidity, and therefore on marine mammals, would be minimal and temporary. In general, the area likely impacted by the proposed construction activities is relatively small compared to the available marine mammal habitat in and around Whittier Harbor.
Potential Effects on Prey. Sound may affect marine mammals through impacts on the abundance, behavior, or distribution of prey species ( e.g., crustaceans, cephalopods, fishes, and zooplankton). Marine mammal prey varies by species, season, and location and, for some, is not well documented. Studies regarding the effects of noise on known marine mammal prey are described here.
Fishes utilize the soundscape and components of sound in their environment to perform important functions such as foraging, predator avoidance, mating, and spawning ( e.g., Zelick et al., 1999; Fay, 2009). Depending on their hearing anatomy and peripheral sensory structures, which vary among species, fishes hear sounds using pressure and particle motion sensitivity capabilities and detect the motion of surrounding water (Fay et al., 2008). The potential effects of noise on fishes depends on the overlapping frequency range, distance from the sound source, water depth of exposure, and species-specific hearing sensitivity, anatomy, and physiology. Key impacts to fishes may include behavioral responses, hearing damage, barotrauma (pressure-related injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent low-frequency sounds and behavioral responses such as flight or avoidance are the most likely effects. Short duration, sharp sounds can cause overt or subtle changes in fish behavior and local distribution. The reaction of fish to noise depends on the physiological state of the fish, past exposures, motivation ( e.g., feeding, spawning, migration), and other environmental factors. Hastings and Popper (2005) identified several studies that suggest fish may relocate to avoid certain areas of sound energy. Additional studies have documented effects of pile driving on fishes ( e.g. Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Several studies have demonstrated that impulse sounds might affect the distribution and behavior of some fishes, potentially impacting foraging opportunities or increasing energetic costs ( e.g., Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999; Paxton et al., 2017). However, some studies have shown no or slight reaction to impulse sounds ( e.g., Peña et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott et al., 2012). More commonly, though, the impacts of noise on fishes are temporary.
SPLs of sufficient strength have been known to cause injury to fishes and fish mortality (summarized in Popper et al., 2014). However, in most fish species, hair cells in the ear continuously regenerate and loss of auditory function likely is restored when damaged cells are replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of 4 to 6 dB was recoverable within 24 hours for one species. Impacts would be most severe when the individual fish is close to the source and when the duration of exposure is long. Injury caused by barotrauma can range from slight to severe and can cause death, and is most likely for fish with swim bladders. Barotrauma injuries have been documented during controlled exposure to impact pile driving (Halvorsen et al., 2012a; Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as marine mammal prey could be temporarily affected by noise from pile installation and removal. The frequency range in which fishes generally perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution may change, especially with strong and/or intermittent sounds that could harm fishes. High underwater SPLs have been documented to alter behavior, cause hearing loss, and injure or kill individual fish by causing serious internal injury (Hastings and Popper, 2005).
[top] Zooplankton is a food source for several marine mammal species, as well as a food source for fish that are then preyed upon by marine mammals. Population effects on zooplankton could
The greatest potential impact to marine mammal prey during construction would occur during vibratory pile driving. In-water construction activities would only occur during daylight hours, allowing fish to forage and transit the project area in the evening. Vibratory pile driving would possibly elicit behavioral reactions from fishes such as temporary avoidance of the area but is unlikely to cause injuries to fishes or have persistent effects on local fish populations. Construction is expected to have minimal permanent and temporary impacts on benthic invertebrate species, which are known marine mammal prey source. In addition, the area in question is generally considered low-quality habitat since it is already highly developed and experiences a high level of anthropogenic noise from normal operations and other vessel traffic.
Potential Effects on Foraging Habitat
This proposed project is not expected to result in any habitat related effects that could cause significant or long-term negative consequences for individual marine mammals or their populations, since installation and removal of in-water piles would be temporary and intermittent. The total seafloor area affected by pile installation and removal is a very small area compared to the vast foraging area available to marine mammals outside this project area. For marine mammals, while the area is commonly used or traversed, the proposed project area does not contain any particularly high-value habitat and is not usually important to any of the other species potentially affected by CoW's proposed activities. While opportunistic foraging could occur, more foraging habitat is available in the Passage Canal and Prince William Sound. Overall, the area impacted by the project is relatively small compared to the available habitat just outside the project area, and there are no areas of particular importance that would be impacted by this project during the period planned for activities to occur ( i.e., September through September). Any behavioral avoidance by fish of the disturbed area would still leave significantly large areas of fish and marine mammal foraging habitat in the nearby vicinity. As described in the preceding, the potential for the CoW's construction to affect the availability of prey to marine mammals or to meaningfully impact the quality of physical or acoustic habitat is considered insignificant. Therefore, impacts of the project are not likely to have adverse effects on marine mammal foraging habitat in the proposed project area.
In summary, given the relatively small areas potentially being effected, as well as the temporary and mostly transitory nature of the proposed construction activities, any adverse effects from CoW's activities on prey habitat or prey populations are expected to be minor and temporary. The most likely impact to fishes at the project site would be temporary avoidance of the area. Any behavioral avoidance by fish of the disturbed area would still leave significantly large areas of fish and marine mammal foraging habitat in the nearby vicinity. Thus, we preliminarily conclude that impacts of the specified activities are not likely to have more than short-term adverse effects on any prey habitat or populations of prey species. Further, any impacts to marine mammal habitat are not expected to result in significant or long-term consequences for individual marine mammals, or to contribute to adverse impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes proposed for authorization through the IHA, which will inform NMFS' consideration of "small numbers," the negligible impact determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these activities. Except with respect to certain activities not pertinent here, section 3(18) of 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).
Authorized takes would be by Level B harassment only, in the form behavioral reactions for individual marine mammals resulting from exposure to vibratory pile driving. Based on the nature of the activity and the anticipated effectiveness of the mitigation measures ( i.e., enhanced shutdown zone around the approximate 25 m (82 ft) distance to the Level A harassment threshold) discussed in detail below in the Proposed Mitigation section, Level A harassment is neither anticipated nor proposed to be authorized. Additionally, as described previously, no serious injury or mortality is anticipated or proposed to be authorized for this activity. Below we describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by considering: (1) acoustic criteria above which NMFS believes the best available science indicates marine mammals will likely be behaviorally harassed or incur some degree of AUD INJ; (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and, (4) the number of days of activities. We note that while these factors can contribute to a basic calculation to provide an initial prediction of potential takes, additional information that can qualitatively inform take estimates is also sometimes available ( e.g., previous monitoring results or average group size). Below, we describe the factors considered here in more detail and present the proposed take estimates.
Acoustic Criteria
[top] NMFS recommends the use of acoustic criteria that identify the received level of underwater sound above which exposed marine mammals would be reasonably expected to be behaviorally harassed (equated to Level B harassment) or to incur AUD INJ of some degree (equated to Level A harassment). We note that the criteria for AUD INJ, as well as the names of two hearing groups, have been recently updated (NMFS, 2024) as reflected below in the Level A Harassment section.
Level B Harassment. Though significantly driven by received level, the onset of behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source or exposure context ( e.g., frequency, predictability, duty cycle, duration of the exposure, signal-to-noise ratio, distance to the source), the environment ( e.g., bathymetry, other noises in the area, predators in the area), and the receiving animals (hearing, motivation, experience, demography, life stage, depth) and can be difficult to predict ( e.g., Southall et al., 2007, 2021; Ellison et al., 2012). Based on what the available science indicates and the practical need to use a threshold based on a metric that is both predictable and measurable for most activities, NMFS typically uses a generalized acoustic threshold based on received level to estimate the onset of behavioral harassment. NMFS generally predicts that marine mammals are likely to be behaviorally harassed in a manner considered to be Level B harassment when exposed to underwater anthropogenic noise above root-mean-squared pressure received levels (RMS SPL) of 120 dB (referenced to re 1 µPa)) for continuous ( e.g., vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 µPa for non-explosive impulsive ( e.g., seismic airguns) or intermittent ( e.g., scientific sonar) sources.
For in-air sounds, NMFS predicts that harbor seals exposed above received levels of 90 dB re 20 µPa (RMS) will be behaviorally harassed, and other pinnipeds will be harassed when exposed above 100 dB re 20 µPa (RMS). Generally speaking, Level B harassment take estimates based on these behavioral harassment thresholds are expected to include any likely takes by TTS as, in most cases, the likelihood of TTS occurs at distances from the source less than those at which behavioral harassment is likely. TTS of a sufficient degree can manifest as behavioral harassment, as reduced hearing sensitivity and the potential reduced opportunities to detect important signals ( e.g., conspecific communication, predators, prey) may result in changes in behavior patterns that would not otherwise occur.
CoW's proposed construction includes the use of continuous ( i.e., vibratory pile driving) sources, and therefore the RMS SPL threshold of 120 dB re 1 µPa is applicable.
Level A harassment. NMFS' Updated Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 3.0) (NMFS, 2024) identifies dual criteria to assess AUD INJ (Level A harassment) to five different underwater marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive) (table 4). CoW's proposed construction includes the use of a non-impulsive (vibratory pile driving) source.
The 2024 Updated Technical Guidance criteria include both updated thresholds and updated weighting functions for each hearing group. The thresholds are provided in table 4. The references, analysis, and methodology used in the development of the criteria are described in NMFS' 2024 Updated Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools .
| Hearing group | AUD INJ onset acoustic thresholds?* (received level) | Impulsive | Non-impulsive |
|---|---|---|---|
| Low-Frequency (LF) Cetaceans | Cell 1: L pk,flat : 222 dB; L E,LF,24h : 183 dB | Cell 2: L E,LF,24h : 197 dB. | |
| High-Frequency (HF) Cetaceans | Cell 3: L pk,flat : 230 dB; L E,HF,24h : 193 dB | Cell 4: L E,HF,24h : 201 dB. | |
| Very High-Frequency (VHF) Cetaceans | Cell 5: L pk,flat : 202 dB; L E,VHF,24h : 159 dB | Cell 6: L E,VHF,24h : 181 dB. | |
| Phocid Pinnipeds (PW) (Underwater) | Cell 7: L pk,flat : 223 dB; L E,PW,24h : 183 dB | Cell 8: L E,PW,24h : 195 dB. | |
| Otariid Pinnipeds (OW) (Underwater) | Cell 9: L pk,flat : 230 dB; L E,OW,24h : 185 dB | Cell 10: L E,OW,24h : 199 dB. | |
| *?Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-impulsive sources. | |||
| Note: Peak sound pressure level ( L p,0-pk ) has a reference value of 1 µPa, and weighted cumulative sound exposure level ( L E,p ) has a reference value of 1 µPa 2 s. In this table, criteria are abbreviated to be more reflective of International Organization for Standardization standards (ISO, 2017; ISO, 2020). The subscript "flat" is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing range of marine mammals underwater ( i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted cumulative sound exposure level criteria 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 criteria will be exceeded. | |||
Ensonified Area
Here, we describe operational and environmental parameters of the activity that are used in estimating the area ensonified above the acoustic thresholds, including source levels and transmission loss coefficient.
[top] The sound field in the proposed project area is the existing background noise and any additional construction noise produced from the proposed project. Marine mammals are only expected to be affected by sound generated by CoW's primary component of the project ( i.e., vibratory pile driving). The source level assumed for both removal and installation activities is based on reviews of measurements of the same or similar types and dimensions of piles available in the literature and from similar coastal construction projects. The source levels for the piles and activity are presented in table 5. The source levels for vibratory removal and installation of piles of the same material and diameter are assumed to be the same.
| Method and pile type | Sound source level at 10 meters | Proxy source |
|---|---|---|
| Vibratory Hammer | dB RMS | Proxy Source. |
| 16-inch (41 cm) steel pile installation | 155 | Denes et al. (2016). |
| 12- to 16-inch (30 to 41 cm) timber pile removal | 162 | Denes et al. (2016). |
Transmission Loss ( TL ) is the decrease in acoustic intensity as an acoustic pressure wave propagates out from a source. TL parameters vary with frequency, temperature, sea conditions, current, source and receiver depth, water depth, water chemistry, and bottom composition and topography. The general formula for underwater TL is:
TL = B × Log10(R1/R2),
where:
TL = transmission loss in dB,
B = transmission loss coefficient,
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.
Absent site-specific acoustical monitoring with differing measured TL, a practical spreading value of 15 is used as the TL coefficient in the above formula. Site-specific TL data for Whittier is not available; therefore, the default coefficient of 15 is used to determine the distances to the Level A harassment and Level B harassment thresholds.
The ensonified area associated with Level A harassment is more technically challenging to predict due to the need to account for a duration component. Therefore, NMFS developed an optional User Spreadsheet tool to accompany the 2024 Updated Technical Guidance that can be used to relatively simply predict an isopleth distance for use in conjunction with marine mammal density or occurrence to help predict potential takes. We note that because of some of the assumptions included in the methods underlying this optional tool, we anticipate that the resulting isopleth estimates are typically going to be overestimates of some degree, which may result in an overestimate of potential take by Level A harassment. However, this optional tool offers the best way to estimate isopleth distances when more sophisticated modeling methods are not available or practical. For stationary sources, such as vibratory pile driving, the optional User Spreadsheet tool predicts the distance at which, if a marine mammal remained at that distance for the duration of the activity, it would be expected to incur auditory injury. Inputs used in the optional User Spreadsheet tool, the resulting estimated isopleths, and the resulting zones of influence ( i.e., areas in square kilometers (km 2 )) are reported below in tables 6, 7, and 8, respectively.
| User spreadsheet variables and inputs | Activity analyzed | Vibratory steel pile installation | Vibratory steel pile removal | Vibratory timber pile removal |
|---|---|---|---|---|
| Spreadsheet tab used | A.1) Vibratory pile driving | A.1) Vibratory pile driving | A.1) Vibratory pile driving. | |
| Proxy used | 18-inch (46 cm) pile from Denes et al. (2016) | 18-inch (46 cm) pile from Denes et al. (2016) | 12- to 16-inch (30-41 cm) timber pile from CALTRANS (2020). | |
| Sound Pressure Level (dB) | 155 | 155 | 162. | |
| Distance associated with sound pressure level (meters) | 10 | 10 | 10. | |
| Transmission loss coefficient | 15 | 15 | 15. | |
| Number of piles removed/installed per day | 12 | 10 | 12. | |
| Duration to drive each pile (minutes) | 60 | 5 | 5. | |
| Duration of sound production in a day (seconds) | 43,200 | 3,000 | 3,600. | |
| Marine mammal WFA (kHz) | 2.5 | 2.5 | 2.5. | |
| Cumulative SEL at measured distance | 201.35 | 189.77 | 197.56. |
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| Species group | Level A harassment | Current threshold (dB; SEL cum ) | Distance to threshold (meters) | Level B harassment | Current threshold (dB; SPL RMS ) | Distance to threshold (meters) |
|---|---|---|---|---|---|---|
| Vibratory Steel Pile Installation (16-inch (41 cm)) | ||||||
| Low-frequency cetaceans | 197 | 19.2 | 120 | a ?2,154.4 | ||
| High-frequency cetaceans | 201 | 7.4 | ||||
| Very high-frequency cetaceans | 181 | 15.7 | ||||
| Phocid pinnipeds (in water) | 195 | 24.8 | ||||
| Otariid pinnipeds (in water) | 199 | 8.3 | ||||
| Vibratory Steel Pile Removal (16-inch (41 cm)) | ||||||
| Low-frequency cetaceans | 197 | 3.3 | 120 | a ?2,154.4 | ||
| High-frequency cetaceans | 201 | 1.2 | ||||
| Very high-frequency cetaceans | 181 | 2.7 | ||||
| Phocid pinnipeds (in water) | 195 | 4.2 | ||||
| Otariid pinnipeds (in water) | 199 | 1.4 | ||||
| Vibratory Timber Pile Removal (12- to 16-inch (30-41 cm)) | ||||||
| Low-frequency cetaceans | 197 | 10.8 | 120 | a ?6,309.6 | ||
| High-frequency cetaceans | 201 | 4.1 | ||||
| Very high-frequency cetaceans | 181 | 8.8 | ||||
| Phocid pinnipeds (in water) | 195 | 13.8 | ||||
| Otariid pinnipeds (in water) | 199 | 4.7 | ||||
| a ?Distances represent the calculated radius of the zone. The actual zone may be truncated by landforms. For these zones, the estimated maximum distance that sound would travel in water before being truncated by land is approximately 1,880 meters for the East Unit and 1,700 meters for the West Unit. | ||||||
| Activity | Project unit | Distance (meters) and (area (km 2 )) to NMFS' thresholds | Level A harassment | LFC | HFC | VHFC | PW | OW | Level B harassment? a | All marine mammals |
|---|---|---|---|---|---|---|---|---|---|---|
| Vibratory pile driving/removal activities | ||||||||||
| 12- to 16-inch (30-41 cm) timber pile removal | East West | 10.8 (0.025) 10.8 (0.019) | 4.1 (0.021) 4.1 (0.015) | 8.8 (0.024 8.8 (0.018) | 13.8 (0.027) 13.8 (0.021) | 4.7 (0.021) 4.7 (0.016) | 6,309.6 (0.650) 6,309.6 (1.385) | |||
| 16-inch (41 cm) steel pile removal | East | 3.3 (0.020) | 1.2 (0.019) | 2.7 (0.02) | 4.2 (0.021) | 1.4 (0.019) | 2,154.4 (0.650) | |||
| West | 3.3 (0.015) | 1.2 (0.014) | 2.7 (0.015) | 4.2 (0.015) | 1.4 (0.014) | 2,154.4 (1.385) | ||||
| 16-inch (41 cm) steel pile installation | East West | 19.2 (0.030) 19.2 (0.023) | 7.4 (0.023) 7.4 (0.017) | 15.7 (0.028) 15.7 (0.022) | 24.8 (0.033) 24.8 (0.026) | 8.3 (0.023) 8.3 (0.018) | 2,154.4 (0.650) 2,154.4 (1.385) | |||
| All piles (in-air) | East | PW: 31.7 (0.037) OW: 10.02 (0.028) | ||||||||
| West | PW: 31.7 (0.029) OW: 10.02 (0.021) | |||||||||
| Note: LFC = low-frequency cetaceans; HFC = high-frequency cetaceans; VHFC = very high-frequency cetaceans; PW = phocid pinnipeds (in-water); OW = otariids pinnipeds (in-water). | ||||||||||
| a Distances represent the calculated radius of the zone. The actual km 2 zones may be truncated by landforms. | ||||||||||
Marine Mammal Occurrence and Take Estimation
In this section, we provide information about the occurrence of marine mammals, including density or other relevant information, which will inform the take calculations. Next, we describe how all of the information described above is synthesized to produce a quantitative estimate of the take that is reasonably likely to occur and proposed for authorization.
CoW provided estimation count information based on a synthetization of different resources, including a local whale watching company, reports from previous marine construction projects in the Whittier area, and the available scientific literature (Solstice Alaska Consulting, Inc., 2022; Alaska Department of Transportation and Public Facilities, 2019; Moran et al., 2018; Olsen et al., 2018; Solstice Alaska Consulting, Inc., 2024; Leonard and Wisdom, 2020). Frequency of sightings were determined by first grouping each species/stock into " common, " " infrequent, " " rare, " or " very rare ". Species/stocks who were determined as " common " or " infrequent" were assumed that they could occur at least once per day; other species/stocks who were labeled as " rare " or " very rare " were assumed that occurrence in the project area would be approximately two to four times per month.
[top] More specific information on the occurrence information incorporated into the analysis can be found in table 6 of CoW's ITA application and is not repeated here; instead, we reference the reader there for additional information. For NMFS' analysis, we reviewed the group sizes and occurrence information synthesized in the application and we provide the numerical values here in table 9.
| Species | Frequency determination | Occurrence value | Group size (individuals) |
|---|---|---|---|
| Dall's porpoise | Infrequent | Two groups per month | 5 |
| Killer whale | Infrequent | Two groups per month | 14 |
| Harbor seal | Common | One group per day | 2 |
| Steller sea lion | Common | One group per day | 2 |
Next, all available information was utilized to determine the proposed take for marine mammals incidental to CoW's project. In using the daily occurrence estimates for each species, the estimated group sizes and the number of days or months for each specific type of pile driving were multiplied together (see the below formula):
Estimated take = group size × groups per day/month × # of days of pile driving
The results of this analysis can be found in table 10, where the number of takes that NMFS proposes for authorization are presented.
| Marine mammal species | Stock | N EST | Proposed take | Level A harassment? a | Level B harassment? a | Total | Proposed stock percentage to be taken? b |
|---|---|---|---|---|---|---|---|
| Killer whale | Alaska Resident | 1,920 | 0 | 21 | 21 | 1.1 | |
| Gulf of Alaska/Aleutian Islands/Bering Sea Transient | 587 | 0 | 7 | 7 | 1.2 | ||
| Dall's porpoise | Alaska | 13,110 | 0 | 10 | 10 | 0.1 | |
| Harbor seal | Prince William Sound | c ?44,756 | 0 | 58 | 58 | 0.1 | |
| Steller sea lion | Western | 49,837 | 0 | 58 | 58 | 0.1 | |
| a ?The applicant did not request take by Level A harassment in their final ITA application, nor does NMFS expect take by Level A harassment from the described specified activities; however, NMFS is displaying the column for clarity and descriptive purposes. Only take by Level B harassment was requested, is expected, and proposed for authorization. | |||||||
| b ?The percent stock taken calculation is based on the total estimated take expected (in this case, all from Level B harassment). | |||||||
| c ?No stock abundance is available in NMFS' draft 2024 SARs for this stock; the value presented here is from Young et al. (2023) for the small numbers calculation. | |||||||
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to the activity, and other means of effecting the least practicable impact on the species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stock for taking for certain subsistence uses (latter not applicable for this action). NMFS regulations require applicants for incidental take authorizations to include information about the availability and feasibility (economic and technological) of equipment, methods, and manner of conducting the activity or other means of effecting the least practicable adverse impact upon the affected species or stocks, and their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to ensure the least practicable adverse impact on species or stocks and their habitat, as well as subsistence uses where applicable, NMFS considers two primary factors:
(1) The manner in which, and the degree to which, the successful implementation of the measure(s) is expected to reduce impacts to marine mammals, marine mammal species or stocks, and their habitat. This considers the nature of the potential adverse impact being mitigated (likelihood, scope, range). It further considers the likelihood that the measure will be effective if implemented (probability of accomplishing the mitigating result if implemented as planned), the likelihood of effective implementation (probability implemented as planned), and;
(2) The practicability of the measures for applicant implementation, which may consider such things as cost and impact on operations.
In addition to the measures described later in this section, CoW would be required to follow these general mitigation measures:
• Take proposed to be authorized, by Level B harassment only, would be limited to the species and numbers listed in tables 2 and 10. Proposed construction activities must be halted upon observation of either a species for which incidental take would not be authorized or a species for which incidental take would be authorized but the authorized number of takes has been met, entering or is within the harassment zone;
• The taking by Level A harassment, serious injury, or death of any of the species listed in tables 2 and 10 or any taking of any other species of marine mammal would be prohibited and would result in the modification, suspension, or revocation of the IHA, if issued. Any taking exceeding the authorized amounts listed in table 10 would be prohibited and would result in the modification, suspension, or revocation of the IHA, if issued;
[top] • Ensure that construction supervisors and crews, the marine mammal monitoring team, and relevant CoW staff are trained prior to the start of all construction activities, so that responsibilities, communication procedures, marine mammal monitoring protocol, and operational procedures are clearly understood. New personnel joining during the project must be trained prior to commencing work;
• CoW, construction supervisors and crews, protected species observers (PSOs), and relevant project staff must avoid direct physical interaction with marine mammals during construction activities. If a marine mammal comes within 10 m (32.8 ft) of such activity, operations must cease and vessels must reduce speed to the minimum level required to maintain steerage and safe working conditions, as necessary to avoid direct physical interaction;
• If poor weather conditions restrict the PSO's ability to make observations within the Level A and B harassment zone of pile driving ( e.g., if there is excessive wind or fog), pile installation and removal will be halted; and
• Employ PSOs and establish monitoring locations as described in Section 5 of the IHA and within CoW's Marine Mammal Monitoring Plan (see the proposed Plan found on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities ). CoW would be required to monitor the project area to the maximum extent possible based on the required number of PSOs, required monitoring locations, and environmental conditions.
Additionally, the following mitigation measures apply to CoW's in-water construction activities.
Pre- and Post-Activity Monitoring
CoW would be required to establish pre- and post-monitoring zones with radial distances (based on the distances to the Level B harassment threshold), as identified in table 11, for all construction activities. All pre-start clearance monitoring must be conducted during periods of visibility sufficient for the PSO to determine that the shutdown zones (indicated in table 12) are clear of marine mammals. All monitoring would be required to take place from 30 minutes prior to initiation of pile driving activity ( i.e., pre-clearance monitoring) through 30 minutes post-completion of pile driving activity. Pile driving may commence following 30 minutes of observation when the determination is made that the shutdown zones are clear of marine mammals (see table 12 further below).
| Activity | Level B harassment monitoring zones for all marine mammals (meters)? a | East unit | West unit |
|---|---|---|---|
| Vibratory pile driving installation/removal | |||
| 12- to 16-inch (30-41 cm) timber pile removal | b ?1,880 | b ?1,700 | |
| 16-inch (41 cm) steel pile removal | b ?1,880 | b ?1,700 | |
| 16-inch (41 cm) steel pile installation | b ?1,880 | b ?1,700 | |
| All piles (in-air) | 35 c ?(harbor seals) | ||
| 15 c ?(Steller sea lions) | |||
| a ?The distances refer to the maximum radius of the zone and are rounded to the nearest whole number. | |||
| b ?While NMFS does recognize that these zones are calculated to be much larger ( i.e., 6,310 m and 2,155 m), the estimated maximum distance that sound would travel in water before being truncated by land is approximately 1,880 meters for the East Unit and 1,700 meters for the West Unit so we have carried these forward as more realistic monitoring zones. | |||
| c ?While no take by harassment is expected from in-air activities, these zones are included in the event that hauled out pinnipeds enter the water during active pile driving. | |||
If a break in vibratory pile driving occurs for a duration of 30 minutes or longer, CoW must begin the 30-minute pre-clearance monitoring again to ensure the applicable monitoring zones are clear of marine mammals.
Shutdown Zones
CoW would be required to establish shutdown zones with radial distances, as identified in table 12, for all construction activities. The purpose of a shutdown zone is generally to define an area within which shutdown of the activity would occur upon sighting of a marine mammal (or in anticipation of an animal entering the defined area). The shutdown zone during vibratory pile driving is based on the greatest distance to Level A harassment threshold ( i.e., 24.8 m (81.4 ft) (refer to table 8)), initially rounded up to the nearest whole number (25 m (82 ft)). A general 10-m (32.8-ft) shutdown zone would be required for all other activities where harassment is not expected ( i.e., movement of the barges to the pile locations, movement of the barges during position and removal of the float systems, and positioning/stabbing of the pile on the substrate using a crane).
PSOs will be stationed at various land-based observations points during the proposed construction activities and will monitor continuously during in-water work. If a marine mammal is observed entering or within the shutdown zones indicated in table 12, pile-driving activity must be delayed or halted. If pile driving is delayed or halted due to the presence of a marine mammal, the activity may not commence or resume until either the animal has voluntarily exited and been visually confirmed beyond the shutdown zones or 15 minutes have passed without re-detection of the animal. If a marine mammal comes within or approaches the shutdown zone indicated in table 12, such operations must cease.
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| Specified activity | Proposed level A harassment shutdown zones (meters)? a | HFC | VHFC | PW | OW |
|---|---|---|---|---|---|
| Vibratory pile driving installation/removal | |||||
| 12- to 16-inch (30-41 cm) timber pile removal | 10 | 10 | 15 | 10 | |
| 16-inch (41 cm) steel pile removal | 10 | 10 | 10 | 10 | |
| 16-inch (41 cm) steel pile installation | 10 | 20 | 25 | 10 | |
| Note: HFC = high-frequency cetaceans; VHFC = very high-frequency cetaceans; PW = phocid pinnipeds (in-water); OW = otariids pinnipeds (in-water). | |||||
| a ?The distances refer to the maximum radius of the Level A harassment zone and are rounded to the nearest whole number. | |||||
CoW would also be required to establish shutdown zones for all marine mammals for which take has not been authorized or for which incidental take has been authorized but the authorized number of takes has been met. These zones are equivalent to the Level B harassment zones for each activity. If a marine mammal species for which take is not authorized by this IHA, if issued, enters the shutdown zone, all in-water activities would cease until the animal leaves the zone or has not been observed for at least 15 minutes. CoW would then be required to notify NMFS about the species and precautions taken. Vibratory pile driving would proceed if the non-IHA species is observed to leave the Level A harassment zone or if 15 minutes have passed since the last observation.
If shutdown and/or clearance procedures would result in an imminent safety concern, as determined by CoW or its designated officials, the in-water activity would be allowed to continue until the safety concern has been addressed, and the animal would be continuously monitored.
Monitoring Zone During Construction Activities
All marine mammals would be monitored in the Level B harassment zone and throughout the area as far as visual monitoring can take place. If a marine mammal enters the Level B harassment zone, in-water activities would continue and the animal's presence within the estimated harassment zone would be documented.
Based on our evaluation of the proposed mitigation measures, NMFS has preliminarily determined that the measures provide the means of effecting the least practicable impact on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of the MMPA states that NMFS must set forth requirements pertaining to the monitoring and reporting of such taking. The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for authorizations must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present while conducting the activities. Effective reporting is critical, for both compliance as well as ensuring that the most value is obtained from the required monitoring.
Monitoring and reporting requirements prescribed by NMFS should contribute to improved understanding of one or more of the following:
• Occurrence of marine mammal species or stocks in the area in which take is anticipated ( e.g., presence, abundance, distribution, density);
• Nature, scope, or context of likely marine mammal exposure to potential stressors/impacts (individual or cumulative, acute or chronic), through better understanding of: (1) action or environment ( e.g., source characterization, propagation, ambient noise); (2) affected species ( e.g., life history, dive patterns); (3) co-occurrence of marine mammal species with the activity; or (4) biological or behavioral context of exposure ( e.g., age, calving or feeding areas);
• Individual marine mammal responses (behavioral or physiological) to acoustic stressors (acute, chronic, or cumulative), other stressors, or cumulative impacts from multiple stressors;
• How anticipated responses to stressors impact either: (1) long-term fitness and survival of individual marine mammals; or (2) populations, species, or stocks;
• Effects on marine mammal habitat ( e.g., marine mammal prey species, acoustic habitat, or other important physical components of marine mammal habitat); and,
• Mitigation and monitoring effectiveness.
CoW would be required to abide by all monitoring and reporting measures contained within the IHA, if issued, and their Marine Mammal Monitoring Plan (see the proposed Plan found on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities ). A summary of those measures, and additional requirements proposed by NMFS, is described below.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the conditions in this section and the IHA, if issued. Marine mammal monitoring during vibratory pile driving activities would be conducted by PSOs who meet the following requirements:
• PSOs must be independent of the activity contractor (for example, employed by a subcontractor) and have no other assigned tasks during monitoring periods;
• At least one PSO would have prior experience performing the duties of a PSO during construction activity pursuant to a NMFS-issued incidental take authorization;
• Other PSOs may substitute relevant experience, education (degree in biological science or related field), or training for prior experience performing the duties of a PSO during construction activity pursuant to a NMFS-issued incidental take authorization; and
• Where a team of three or more PSOs is required, a lead observer or monitoring coordinator would be designated. The lead observer would be required to have prior experience performing the duties of a PSO during construction activities pursuant to a NMFS-issued incidental take authorization.
PSOs must also have the following additional qualifications:
• Ability to conduct field observations and collect data according to assigned protocols;
• Experience or training in the field identification of marine mammals, including the identification of behaviors;
[top] • Sufficient training, orientation, or experience with the construction operation to provide for personal safety during observations;
• Writing skills sufficient to prepare a report of observations including but not limited to the number and species of marine mammals observed; dates and times when in-water construction activities were conducted; dates, times and reason for implementation of mitigation (or why mitigation was not implemented when required); and marine mammal behavior; and
• Ability to communicate orally, by radio or in person, with project personnel to provide real-time information on marine mammals observed in the area as necessary.
CoW would be required to establish monitoring locations as described in the "Marine Mammal Monitoring Plan" (see the proposed Plan found on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities ). For all pile-driving activities, at least two PSOs would be onsite during in-water activities associated with the proposed Project. These PSOs would be stationed at the Whittier Harbor breakwater near the picnic shelter ("Station 1"), at the Whittier fuel dock ("Station 2"), and at the City of Whittier campground ("Station 3"). The number and locations of PSOs would be based on two work scenarios: during more generic activities, such as all in-water construction not involving any pile driving and during all barge movement ("Scenario #1"); and, during removal and installation of piles using an active vibratory pile hammer ("Scenario #2"). See figure 2 for the planned PSO locations. PSOs would record all observations of marine mammals, regardless of distance from the pile being driven, as well as the additional data indicated below and in the draft IHA, if issued.
[Federal Register graphic "EN05JN25.001" is not available. Please view the graphic in the PDF version of this document.]
Figure 2-Proposed PSO Monitoring Locations During Vibratory Pile Driving Activities for the Whittier Harbor Rebuild Phase III Project.
Monitoring would be conducted 30 minutes before, during, and 30 minutes after all in water construction activities. All PSOs would have access to high-quality binoculars and/or spotting scopes to monitor distances, hand-held global positioning system (GPS) unit/grid-maps and compass/clinometer, and portable two-way radios for maintaining contact with work crews, CoW inspectors, and other PSOs. In addition, CoW would record all incidents of marine mammal occurrence, regardless of distance from the construction activities, and would document any behavioral reactions in concert with distance from piles being driven or removed. Pile driving activities include the time to install or remove a single pile or series of piles, as long as the time elapsed between uses of the pile driving equipment is no more than 30 minutes.
CoW would conduct briefings between construction supervisors and crews, PSOs, CoW staff prior to the start of all pile-driving activities and when new personnel join the work. These briefings would explain responsibilities, communication procedures, marine mammal monitoring protocol, and operational procedures.
AT1 Killer Whale Dorsal Fin Monitoring
Although take of AT1 killer whales is not proposed to be authorized, given the limited likelihood for their presence to overlap the project area in space and time, NMFS has included in the proposed IHA recent photographs (from 2021) of the dorsal fins of all seven members of the AT1 stock. These images are provided courtesy of the North Gulf Oceanic Society ( http://www.whalesalaska.org ) and would be used to aid PSOs in the identification of these specific individual killer whales and to implement mitigation, if necessary, to avoid take.
Reporting
[top] CoW would be required to submit an annual draft summary report on all construction activities and marine mammal monitoring results to NMFS within 90 days following the end of construction or 60 calendar days prior to the requested issuance of any subsequent IHA for similar activity at the same location, whichever comes first. The draft summary report would include an overall description of construction work completed, a
• Dates and times (begin and end) of all marine mammal monitoring;
• Construction activities occurring during each daily observation period, including: (a) how many and what type of piles were driven or removed; (b) the method of removal and installation ( i.e., vibratory pile driving); and (c) the total duration of time needed to drive each pile via vibratory driving;
• PSO locations during marine mammal monitoring; and
• Environmental conditions during monitoring periods (at beginning and end of PSO shift and whenever conditions change significantly), including Beaufort sea state and any other relevant weather conditions including cloud cover, fog, sun glare, and overall visibility to the horizon, and estimated observable distance.
Upon observation of a marine mammal, the following information must be reported:
• Name of PSO who sighted the animal(s) and PSO location and activity at the time of the sighting;
• Time of the sighting;
• Identification of the animal(s) ( e.g., genus/species, lowest possible taxonomic level, or unidentified), PSO confidence in identification, and the composition of the group if there is a mix of species;
• Distance and bearing of each observed marine mammal relative to the pile being driven or removed for each sighting;
• Estimated number of animals (min/max/best estimate);
• Estimated number of animals by cohort ( e.g., adults, juveniles, neonates, group composition, etc. );
• Animal's closest point of approach and estimated time spent within the estimated harassment zone(s);
• Description of any marine mammal behavioral observations ( e.g., observed behaviors such as feeding or traveling), including an assessment of behavioral responses thought to have resulted from the activity ( e.g., no response or changes in behavioral state such as ceasing feeding, changing direction, flushing, or breaching);
• Number of marine mammals detected within the estimated harassment zones, by species; and
• Detailed information about implementation of any mitigation ( e.g., shutdowns and delays), a description of specified actions that ensured, and resulting changes in behavior of the animal(s), if any.
If no comments are received from NMFS within 30 days after the submission of the draft summary report, the draft report would constitute the final report. If CoW received comments from NMFS, a final summary report addressing NMFS' comments must be submitted within 30 days after receipt of comments.
Reporting Injured or Dead Marine Mammals
In the unanticipated event that the specified activity causes the take of a marine mammal in a manner prohibited by the IHA (if issued), such as an injury, serious injury, or mortality, CoW must immediately cease the specified activities and report the incident to the NMFS Office of Protected Resources ( PR.ITP.MonitoringReports@noaa.gov and ITP.potlock@noaa.gov ), and the NMFS Alaska 24-hour Regional Stranding Hotline (877) 925-7773 or (877) 9-AKR-PRD. The report must include the following information:
• Time, date, and location (latitude/longitude) of the first discovery (and updated location information if known and applicable);
• Species identification (if known) or description of the animal(s) involved;
• Condition of the animal(s) (including carcass condition if the animal is dead);
• Observed behaviors of the animal(s), if alive;
• If available, photographs or video footage of the animal(s); and
• General circumstances under which the animal was discovered.
Activities would not resume until NMFS can review the circumstances surrounding the prohibited take. NMFS would work with CoW to determine what is necessary to minimize the likelihood of further prohibited take and ensure MMPA compliance. CoW cannot resume their activities until NMFS has notified them via letter, email, or telephone.
If CoW discovers an injured or dead marine mammal, and the lead PSO determines that the cause of the injury or death is unknown and the death is relatively recent ( e.g., in less than a moderate state of decomposition as described in the next paragraph), then CoW would immediately report the incident to the NMFS Office of Protected Resources ( PR.ITP.MonitoringReports@noaa.gov and ITP.potlock@noaa.gov ), and the NMFS Alaska 24-hour Regional Stranding Hotline at (877) 925-7773 or (877) 9-AKR-PRD. The report would include the same information identified in the paragraph above. Activities would be able to continue while NMFS reviews the circumstances of the incident. NMFS would work with CoW to determine whether modifications in the activities are appropriate.
Finally, in the event that CoW discovers an injured or dead marine mammal and the lead PSO determines that the injury or death is not associated with or related to the activities authorized in the IHA ( e.g., previously wounded animal, carcass with moderate to advanced decomposition, or scavenger damage), CoW would report the incident to the Permits and Conservation Division, Office of Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or by email to the Alaska Regional Stranding Coordinator, within 24 hours of the discovery. CoW would provide photographs, video footage (if available), or other documentation of the stranded animal sighting to NMFS and the Marine Mammal Stranding Network.
Negligible Impact Analysis and Determination
[top] NMFS has defined negligible impact 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 (50 CFR 216.103). A negligible impact finding is based on the lack of likely adverse effects on annual rates of recruitment or survival ( i.e., population-level effects). An estimate of the number of takes alone is not enough information on which to base an impact determination. In addition to considering estimates of the number of marine mammals that might be "taken" through harassment, NMFS considers other factors, such as the likely nature of any impacts or responses ( e.g., intensity, duration), the context of any impacts or responses ( e.g., critical reproductive time or location, foraging impacts affecting energetics), as well as effects on habitat, and the likely effectiveness of the mitigation. We also assess the number, intensity, and context of estimated takes by evaluating this information relative to population status. Consistent with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, September 29, 1989), the impacts from other past and ongoing anthropogenic activities are incorporated into this analysis via their impacts on the baseline ( e.g., as reflected in the regulatory status of the species, population size and growth rate where known, ongoing sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all of the species listed in tables 2 and 10, given that the anticipated effects of this activity on these different marine mammal stocks are expected to be similar. There is little information about the nature or severity of the impacts, or the size, status, or structure of any of these species or stocks that would lead to a different analysis for this activity.
Pile driving activities associated with CoW's proposed construction project have the potential to disturb or displace marine mammals. Specifically, the project activities may result in take, in the form of Level B harassment only, from underwater sounds generated from vibratory pile driving and removal. Potential takes could occur if individuals are present in the ensonified zone when these activities are underway.
The takes by Level B harassment would be due to potential behavioral disturbance. No serious injury or mortality would be expected, even in the absence of required mitigation measures, given the nature of the activities. The potential for harassment would be further minimized through the construction method and the implementation of the planned mitigation measures (see the Proposed Mitigation section). Any potential for take by Level A harassment is also not expected, given the nature of the activities and the small distance to the Level A harassment threshold. The potential for this is further reduced through the required mitigation measures proposed. Given the small harassment zone estimated for vibratory pile driving and the proximity of this zone near the construction barge, an animal would have to remain within the area estimated to be ensonified above the Level A harassment threshold for multiple hours. This is highly unlikely given the small size of the construction location, marine mammal movement in the area ( i.e., no residential species), and the use of observers stationed around the construction site.
Behavioral responses of marine mammals to pile driving in Whittier are expected to be mild, short term, and temporary. Marine mammals within the Level B harassment zones may not show any visual cues they are disturbed by activities or they could become alert, avoid the area, leave the area, or display other mild responses that are not observable, such as changes in vocalization patterns. Given vibratory pile driving would occur for only a portion of the project's duration, any harassment that may occur would be expected to be temporary. Additionally, many of the species present in region would only be present temporarily based on seasonal patterns or during active transit between other habitats. Pinnipeds in the area would have the ability to haul-out to avoid the activities and no in-air harassment is anticipated from the construction activities planned given the type of activities and short isopleths to the Level B harassment threshold (refer to table 8). These temporarily present species would then be exposed to even smaller periods of noise-generating activity, further decreasing the impacts.
Any impacts on marine mammal prey that would occur during CoW's proposed activities would have, at most, short-term effects on foraging of individual marine mammals, and likely no effect on the populations of marine mammals as a whole. Indirect effects on marine mammal prey during the construction are expected to be minor, and these effects are unlikely to cause substantial effects on marine mammals at the individual level, with no expected effect on annual rates of recruitment or survival.
For all species and stocks, take would occur within a limited, confined area of the stock's range, and, there are no known BIAs near the project area that are expected to be impacted by CoW's proposed activities. While Steller sea lions and harbor seals are the species most likely to occur within the immediate project area, the nearest haul out for Steller sea lions is over 40 km (24.9 mi) away, with the closest known sighting (on a mooring buoy) located approximately 8 km (5 mi) away, all of which is outside of the ensonified zone. For harbor seals, although they have been observed occasionally hauling out within Whittier Harbor, there are no known rookeries or major haul-out areas near the project area. Any other species are likely to be transiting through or by Whittier Harbor but are not expected to remain for any extended duration.
In addition, it is unlikely that minor noise effects in a small, localized area of habitat would have any effect on the reproduction or survival of any individuals, much less the stocks' annual rates of recruitment or survival. In combination, we believe that these factors, as well as the available body of evidence from other similar activities, demonstrate that the potential effects of the specified activities would have only minor, short-term effects on individuals. The specified activities are not expected to impact rates of recruitment or survival and would not be expected to result in population-level impacts.
In summary and as described above, the following factors primarily support our preliminary determination that the impacts resulting from this activity are not expected to adversely affect any of the species or stocks through effects on annual rates of recruitment or survival:
• No serious injury or mortality is anticipated or proposed to be authorized;
• No take by Level A harassment was requested, is expected, or is proposed for authorization;
• For all species and stocks, Whittier Harbor is a very small and peripheral part of their range;
• The intensity of anticipated takes by Level B harassment is relatively low for all stocks. Level B harassment would be primarily in the form of behavioral disturbance, resulting in avoidance of the project areas around where vibratory pile driving is occurring;
• Effects on species that serve as prey for marine mammals from the activities are expected to be short-term and, therefore, any associated impacts on marine mammal feeding are not expected to result in significant or long-term consequences for individuals, or to accrue to adverse impacts on their populations;
• Although the Prince William Sound is part of the critical habitat designated for Steller sea lions (both terrestrial and aquatic habitats), the nearest Steller sea lion haul-out is over 40 km (24.9 mi) away, with the closest known sighting (on a mooring buoy) located approximately 8 km (5 mi) away, all of which is outside of the ensonified zone;
• The project area does not overlap any areas of known important habitat ( i.e., BIAs) for marine mammals;
• The ensonified areas are very small relative to the overall habitat ranges of all species and stocks; and
• There is a lack of anticipated significant or long-term negative effects to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the specified activity on marine mammals and their habitat, and taking into consideration the implementation of the proposed monitoring and mitigation measures, NMFS preliminarily finds that the total marine mammal take from the proposed activity will have a negligible impact on all affected marine mammal species or stocks.
Small Numbers
[top] As noted previously, only take of small numbers of marine mammals may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for specified activities other than military readiness activities. The MMPA does not define small numbers and so, in practice, where estimated numbers are
The instances of take NMFS has proposed to authorize is below one-third of the estimate stock abundance for all species. The number of animals proposed for authorization that could be taken from these stocks would be considered small relative to the relevant stocks' abundances even if each estimated taking occurred to a new individual. While there is a potential for some individuals to be taken multiple times per day, PSOs would count them as separate takes if they cannot be individually identified.
Based on the analysis contained herein of the proposed activity (including the proposed mitigation and monitoring measures) and the anticipated take of marine mammals, NMFS preliminarily finds that small numbers of marine mammals would be taken relative to the population size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified activity will not have an "unmitigable adverse impact" on the subsistence uses of the affected marine mammal species or stocks by Alaskan Natives. NMFS has defined "unmitigable adverse impact" in 50 CFR 216.103 as an impact resulting from the specified activity: (1) That is likely to reduce the availability of the species to a level insufficient for a harvest to meet subsistence needs by: (i) Causing the marine mammals to abandon or avoid hunting areas; (ii) Directly displacing subsistence users; or (iii) Placing physical barriers between the marine mammals and the subsistence hunters; and (2) That cannot be sufficiently mitigated by other measures to increase the availability of marine mammals to allow subsistence needs to be met.
While Alaska Natives have historically hunted sea lions and harbor seals in the Prince William Sound, subsistence species hunted more today consist of salmon, halibut, shellfish, and plants ( i.e., wild berries) with a significant decline in marine mammal hunting overall (Poe et al., 2010). CoW has indicated that the last recorded harvest of marine mammals in Whittier was in 1990 during the harvest of seven marine mammals (per ADF&G, 2024b). While other coastal communities along the Prince William Sound report more recent subsistence harvests ( i.e., Cordova, Chenega, and Tatitlek), subsistence hunters have had to travel further form their communities to be successful when harvesting marine mammals (Keating et al., 2020). However, per Fall and Zimpelman (2016), these reported travel ranges do not extend into the Passage Canal and Cordova, Chenega, and Tatitlek are located at least 60 miles (96.56 km) away by boat.
Because of this, NMFS agrees with CoW's preliminary determination that the proposed project is not likely to adversely affect the availability of any marine mammal species/stocks that would traditionally be used for subsistence purposes, or would affect any subsistence harvest in the region because of the following reasons:
• There is no recently recorded subsistence harvest of marine mammals in the area;
• The construction activities would be localized and temporary in nature;
• The proposed mitigation measures would minimize any disturbances of marine mammals in the area;
• NMFS expects that any effects on marine mammals would not rise above behavioral impacts and would be temporary in nature; and
• No serious injury or mortality is expected to result from the project activities, therefore, the project would not result in a signify ant change to the availability of subsistence resources.
Based on the description of the specified activity, the measures described to minimize adverse effects on the availability of marine mammals for subsistence purposes, and the proposed mitigation and monitoring measures; NMFS has preliminarily determined that there will not be an unmitigable adverse impact on subsistence uses from CoW's proposed activities.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq. ) requires that each Federal agency insure that any action it authorizes, funds, or carries out is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of designated critical habitat. To ensure ESA compliance for the issuance of IHAs, NMFS consults internally whenever we propose to authorize take for endangered or threatened species, in this case with the Alaska Regional Office.
NMFS is proposing to authorize take of Steller sea lions (Western DPS), which are listed under the ESA. The Permits and Conservation Division has requested initiation of section 7 consultation with the Alaska Regional Office for the issuance of this IHA. NMFS will conclude the ESA consultation prior to reaching a determination regarding the proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to issue an IHA to CoW for conducting construction activities as part of the Whittier Harbor Rebuild Phase III Project in Whittier, Alaska from September 15, 2025 through September 14, 2026, provided the previously mentioned mitigation, monitoring, and reporting requirements are incorporated. A draft of the proposed IHA can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and any other aspect of this notice of proposed IHA for CoW's proposed Whittier Harbor Rebuild Phase III Project. We also request comment on the potential renewal of this proposed IHA as described in the paragraph below. Please include with your comments any supporting data or literature citations to help inform decisions on the request for this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal IHA following notice to the public providing an additional 15 days for public comments when (1) up to another year of identical or nearly identical activities as described in the Description of Proposed Activity section of this notice is planned or (2) the activities as described in the Description of Proposed Activity section of this notice would not be completed by the time the IHA expires and a renewal would allow for completion of the activities beyond that described in the Dates and Duration section of this notice, provided all of the following conditions are met:
[top] • A request for renewal is received no later than 60 days prior to the needed renewal IHA effective date (recognizing that the renewal IHA expiration date
• The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the requested renewal IHA are identical to the activities analyzed under the initial IHA, are a subset of the activities, or include changes so minor ( e.g., reduction in pile size) that the changes do not affect the previous analyses, mitigation and monitoring requirements, or take estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the required monitoring to date and an explanation showing that the monitoring results do not indicate impacts of a scale or nature not previously analyzed or authorized.
• Upon review of the request for renewal, the status of the affected species or stocks, and any other pertinent information, NMFS determines that there are no more than minor changes in the activities, the mitigation and monitoring measures will remain the same and appropriate, and the findings in the initial IHA remain valid.
Dated: June 2, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries Service.
[FR Doc. 2025-10232 Filed 6-4-25; 8:45 am]
BILLING CODE 3510-22-P