Proposed Rule2024-24580
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Port of Alaska Modernization Program Phase 2B: Cargo Terminals Replacement Project in Anchorage, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
October 28, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS received a request from the Don Young Port of Alaska (POA) for authorization to take marine mammals incidental to the Cargo Terminals Replacement Project at the existing port facility in Anchorage, Alaska over the course of 5 construction seasons (2026 through 2030). Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is proposing regulations setting forth permissible methods of taking, other means of effecting the least practicable adverse impact on such marine mammal stocks (i.e., mitigation measures), and requirements pertaining to monitoring and reporting such takes and requests comments on the proposed regulations. NMFS will consider public comments prior to making any final decision on the promulgation of the requested MMPA regulations, and NMFS's responses to public comments will be summarized in the final notification of our decision.
Full Text
<html>
<head>
<title>Federal Register, Volume 89 Issue 208 (Monday, October 28, 2024)</title>
</head>
<body><pre>
[Federal Register Volume 89, Number 208 (Monday, October 28, 2024)]
[Proposed Rules]
[Pages 85686-85747]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-24580]
[[Page 85685]]
Vol. 89
Monday,
No. 208
October 28, 2024
Part III
Department of Commerce
-----------------------------------------------------------------------
National Oceanic and Atmospheric Administration
-----------------------------------------------------------------------
50 CFR Part 217
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to the Port of Alaska Modernization Program
Phase 2B: Cargo Terminals Replacement Project in Anchorage, Alaska;
Proposed Rule
Federal Register / Vol. 89, No. 208 / Monday, October 28, 2024 /
Proposed Rules
[[Page 85686]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 241018-0276]
RIN 0648-BM30
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Port of Alaska Modernization
Program Phase 2B: Cargo Terminals Replacement Project in Anchorage,
Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS received a request from the Don Young Port of Alaska
(POA) for authorization to take marine mammals incidental to the Cargo
Terminals Replacement Project at the existing port facility in
Anchorage, Alaska over the course of 5 construction seasons (2026
through 2030). Pursuant to the Marine Mammal Protection Act (MMPA),
NMFS is proposing regulations setting forth permissible methods of
taking, other means of effecting the least practicable adverse impact
on such marine mammal stocks (i.e., mitigation measures), and
requirements pertaining to monitoring and reporting such takes and
requests comments on the proposed regulations. NMFS will consider
public comments prior to making any final decision on the promulgation
of the requested MMPA regulations, and NMFS's responses to public
comments will be summarized in the final notification of our decision.
DATES: Comments and information must be received no later than November
27, 2024.
ADDRESSES: A plain language summary of this proposed rule is available
at <a href="https://www.regulations.gov/docket/NOAA-NMFS-2024-0030">https://www.regulations.gov/docket/NOAA-NMFS-2024-0030</a>. You may
submit comments on this document, identified by NOAA-NMFS-2024-0030, by
the following method:
<bullet> Electronic Submission: Submit all electronic public
comments via the Federal e-Rulemaking Portal. Visit <a href="https://www.regulations.gov">https://www.regulations.gov</a> and type NOAA-NMFS-2024-0030 in the Search box.
Click on the ``Comment'' icon, complete the required fields, and enter
or attach your comments.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
<a href="https://www.regulations.gov">https://www.regulations.gov</a> without change. All personal identifying
information (e.g., name, address, etc.), confidential business
information, or otherwise sensitive information submitted voluntarily
by the sender will be publicly accessible. NMFS will accept anonymous
comments (enter ``N/A'' in the required fields if you wish to remain
anonymous).
Electronic copies of the application and supporting documents, as
well as a list of the references cited in this document, may be
obtained online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization">https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization</a>. In case of problems accessing these documents, please
call the contact listed below.
FOR FURTHER INFORMATION CONTACT: Cara Hotchkin, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, promulgated under the authority of the
MMPA (16 U.S.C. 1361 et seq.), would provide a framework for
authorizing the take of marine mammals incidental to construction
activities associated with the POA's Modernization Program, including
impact and vibratory pile driving.
NMFS received an application from the POA requesting 5-year
regulations and a letter of authorization issued thereunder to take
individuals of seven species, comprising nine stocks of marine mammals
by Level A harassment and Level B harassment incidental to the POA's
activities. No serious injury or mortality is anticipated or proposed
for authorization. Please see Background below for definitions of
harassment.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs
the Secretary of Commerce to allow, upon request, the incidental, but
not intentional taking of small numbers of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region for up to 5 years if,
after notice and public comment, the agency makes certain findings and
promulgates regulations that set forth permissible methods of taking
pursuant to that activity and other means of effecting the ``least
practicable adverse impact'' on the affected species or stocks and
their habitat (see the discussion below in the Proposed Mitigation
section), as well as monitoring and reporting requirements. Section
101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR
part 216, subpart I provide the legal basis for issuing this proposed
rule containing 5-year regulations and for any subsequent Letters of
Authorization (LOAs).
Summary of Major Provisions Within the Proposed Rule
Following is a summary of the major provisions of this proposed
rule regarding POA's activities. These measures include:
<bullet> Prescribing permissible methods of taking of small numbers
of marine mammals by Level A harassment and/or Level B harassment
incidental to the Cargo Terminals Replacement Project;
<bullet> Required monitoring of the construction areas to detect
the presence of marine mammals before beginning construction
activities;
<bullet> Establishment of shutdown zones equivalent to the
estimated Level B harassment zone for beluga whales;
<bullet> Establishment of shutdown zones equivalent to or greater
than the estimated Level A harassment zones for other species;
<bullet> Bubble curtains required for all impact and vibratory
driving of permanent (72-inch (in) (1.83 meter (m))) piles in more than
3 m of water depth in all months and for vibratory driving of all
temporary (24-in (0.61 m) or 36-in (0.91 m)) and permanent (72-in)
piles between August and October;
<bullet> Soft start for impact pile driving to allow marine mammals
the opportunity to leave the area prior to beginning impact pile
driving at full power; and
<bullet> Submittal of monitoring reports including a summary of
marine mammal species and behavioral observations, construction
shutdowns or delays, and construction work completed.
Through adaptive management, the proposed regulations would allow
NMFS Office of Protected Resources to modify (e.g., remove, revise, or
add to) the existing mitigation, monitoring, or reporting measures
summarized above and required by the LOA.
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of
[[Page 85687]]
marine mammals by U.S. citizens who engage in a specified activity
(other than commercial fishing) within a specified geographical region
if certain findings are made and either regulations are promulgated or
an incidental harassment authorization is issued.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). If such findings are made, NMFS must prescribe the
permissible methods of taking and other ``means of effecting the least
practicable adverse impact'' on the affected species or stocks and
their habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance, and on the availability of
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and requirements pertaining to the
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must evaluate our proposed action's (i.e., promulgation of
regulations and subsequent issuance of a LOA thereunder) and
alternatives to that action's potential impacts on the human
environment.
Accordingly, NMFS has prepared an Environmental Assessment (EA) to
evaluate the environmental impacts associated with the issuance of the
proposed regulations and LOA. NMFS' EA is available at <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization">https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization</a>. We will
review all comments submitted in response to this notice prior to
concluding our NEPA process or making a final decision on this request.
Summary of Request
On January 3, 2023, NMFS received a request from the POA for
regulations and a subsequent LOA to take marine mammals incidental to
construction activities related to the POA Modernization Program (PAMP)
Phase 2B: Cargo Terminals Replacement (CTR) at the POA in Anchorage,
Alaska. NMFS provided comments on the application on March 3, 2023,
April 20, 2023, and May 18, 2023. After POA submitted a revised
application on October 13, 2023, and responded to additional questions
sent on December 20, 2023, we determined the application was adequate
and complete on February 12, 2024.
On March 4, 2024, we published a notice of receipt (NOR) of
application in the Federal Register (89 FR 15548), requesting comments
and information during a 30-day public comment period related to the
POA's request. We received one comment letter from the Center for
Biological Diversity. NMFS has reviewed all submitted material and
taken the information into consideration during the drafting of this
proposed rule.
The POA's request is for take of seven species of marine mammals by
Level B harassment and for a subset of these species, Level A
harassment. Neither POA nor NMFS expect serious injury or mortality to
result from the specified activities. If promulgated, the regulations
would be effective for the first 5 construction seasons (2026-2030).
NMFS previously issued IHAs to the POA for similar work (85 FR
19294, April 6, 2020; 86 FR 50057, September 7, 2021; 89 FR 2832,
January 14, 2024). The POA complied with all the requirements (e.g.,
mitigation, monitoring, and reporting) of the previous IHAs and
information regarding their monitoring results may be found in the
Effects of the Specified Activity on Marine Mammals and their Habitat
and Estimated Take of Marine Mammals sections of this proposed rule and
online at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>.
Description of the Specified Activities
Overview
The POA, located on Knik Arm in upper Cook Inlet, provides critical
infrastructure for the citizens of Anchorage and a majority of the
citizens of Alaska. The POA was constructed primarily in the 1960s and
is currently in poor condition and substantially past its initial
design life. The existing cargo terminals T1, T2, and T3 are
deteriorating and in poor structural condition and present safety and
security concerns for human health and the economic stability of the
state of Alaska. The PAMP is designed to replace the existing
facilities with new infrastructure incorporating modern seismic codes
over a 75-year design life. PAMP Phase 2B includes the demolition and
replacement of terminals T1 and T2 and the partial demolition of T3.
This phase is expected to take approximately 6 years of in-water work
to complete. If promulgated, the regulations would be effective for the
first 5 construction seasons (2026-2030).
In-water pile installation will include both temporary (24-in (0.61
m) or 36-in (0.91 m)) and permanent (72-in (1.83 m)) steel pipe piles
by impact and vibratory hammers. Removal of temporary piles (24- or 35-
in) and existing structures (16-in (0.41 m) to 42-in (1.07 m) steel
pipe piles) would be primarily by cutting; dead-pull and vibratory
extraction methods may also be used. Existing piles may also be left
standing in their current positions. In-water work associated with the
project would include installation of approximately 275 permanent piles
and 450 temporary piles and vibratory extraction of approximately 46
temporary piles over the 5-year period.
Dates and Duration
The POA anticipates that in-water construction activities
associated with this proposed rule would begin on April 1, 2026 and
extend through November 30, 2030. In-water pile installation and
removal associated with the CTR project is anticipated to take place
over approximately 689 hours on approximately 337 nonconsecutive days
between the months of April and November over the 5 year period (see
table 1 for estimated production rates and durations). While the exact
sequence of demolition and construction is uncertain, an estimated
schedule is shown in table 2. This schedule is based on best available
information and is not intended to be a limitation on the number of
pile installation or removal hours that may occur in any given month.
The POA has presented the schedule shown in table 2 using the best
available information derived from what is known of the existing Cargo
Terminals site and the POA's experience with similar construction and
demolition projects. A typical construction season at the POA extends
from approximately mid-April to mid-October (6 months) and may include
November. Exact dates of ice-out in the spring and formation of new ice
in the fall vary from year to year and cannot be predicted with
accuracy. In-water pile installation and removal cannot occur during
the winter months when ice is present because of the hazards associated
with moving ice floes that change directions four times a day,
preventing the use of tugs, barges, workboats, and other vessels. Ice
[[Page 85688]]
movement also prevents accurate placement of piles.
While the POA plans to conduct as much work as possible between
April and July, when there is lower Cook Inlet beluga whale (CIBW;
Delphinapterus leucas) abundance (see the Description of Marine Mammals
in the Area of Specified Activities section for details on CIBW
presence at the POA), front-loading of work is dependent on
construction sequencing. Construction sequencing requires that
temporary piles are installed as a template, then larger permanent
piles are installed, and then the temporary piles are removed. This
required sequence plays out many times, in this order, during the open
water construction season. It is not possible to install all of the
larger permanent piles during the early season and install temporary
piles later in the season; the larger and smaller piles must be
alternated. Exact project sequencing and installation and extraction
methods are at the discretion of the construction crew. Construction
dates may change because of unexpected project delays, ongoing
construction activities in other areas of the POA, timing of ice-out
and spring breakup, and other factors. Therefore, the estimated
schedule (table 2) reflects a realistic scenario for the proposed
project, but conditions on the ground may result in slight changes to
this estimated schedule.
[[Page 85689]]
Table 1--Pile Installation and Removal Methods, Estimated Amounts, and Estimated Durations for Years 1-5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Average Average
Total Estimated number Average vibratory impact Estimated Total duration of production
Activity type Pile size and type estimated of piles in the duration per pile duration impact removal or rate, piles Estimated number of
number of water \1\ (minutes) per pile strikes per installation in per day days over 5 years
piles (minutes) pile water (hours) (range)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary pile installation.......... 24- or 36-in (61- or 91- 565 450 30 ......... ........... 225 hours 2-4 144.
cm) Steel pipe.
Temporary pile removal............... 24- or 36-in (61- or 91- 161 46 45 ......... ........... 35 hours 2-4 15.
cm) Steel pipe.
Permanent pile installation.......... 72-in (182-cm) Steel 310 275 10 86 5,743 440 hours 0.5-3 159.
pipe.
---------------------------------------------------------------------------------------------------------------------------------
Total............................ ....................... 1,036 771 ................. ......... ........... 700 hours ........... 337 days.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: cm = centimeter(s); 1--Piles installed above the mean lower low water line are considered ``in the dry'' (i.e., not in-water). It is anticipated that the permanent and temporary piles in
the three bents nearest the shore for all five trestles would be installed in the dry at low tide levels. An additional bent would be installed in the dry for the northernmost trestle of T1
and for the three trestles of T2. These piles are not considered to have the potential for impact to marine mammals and are thus excluded from the following analyses.
Table 2--Estimated Timing and Duration (in Hours per Month) of Pile Installation and Removal Activities \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Duration (hours of activity by month and year)
-----------------------------------------------------------------------------------------------------------------------------------------------
Activity Apr May Jun Jul Aug Sep Oct Nov
-----------------------------------------------------------------------------------------------------------------------------------------------
Imp \2\ Vib \3\ Imp Vib Imp Vip Imp Vib Imp Vib Imp Vib Imp Vib Imp Vib
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1--2026
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24- or 36-in Temporary Pile Installation........ ....... 2.5 ....... 6.0 ....... 6.0 ....... 6.0 ....... 6.0 ....... 6.0 ....... 3.0 ....... 2
24- or 36-in Temporary Pile Removal............. ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8
72-in Permanent Pile Installation \4\........... 7.2 0.8 15.8 1.8 15.8 1.8 15.8 1.8 12.9 1.5 12.9 1.5 12.9 1.5 5.7 0.7
-----------------------------------------------------------------------------------------------------------------------------------------------
Year 1 total hours.......................... 7.2 4.1 15.8 8.6 15.8 8.6 15.8 8.6 12.9 8.3 12.9 8.3 12.9 5.3 5.7 3.4
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Year 2--2027
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24- or 36-in Temporary Pile Installation........ ....... 3.0 ....... 5.0 ....... 5.0 ....... 5.0 ....... 5.0 ....... 5.0 ....... 2.5 ....... 2
24- or 36-in Temporary Pile Removal............. ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... .......
72-in Permanent Pile Installation \4\........... 7.2 0.8 12.9 1.5 12.9 1.5 12.9 1.5 12.9 1.5 11.5 1.3 11.5 1.3 5.7 0.7
-----------------------------------------------------------------------------------------------------------------------------------------------
Year 2 total hours.......................... 7.2 4.6 12.9 7.3 12.9 7.3 12.9 7.3 12.9 7.3 11.5 7.1 11.5 4.6 5.7 2.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Year 3--2028
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24- or 36-in Temporary Pile Installation........ ....... 6.5 ....... 13.0 ....... 13.0 ....... 13.0 ....... 13.0 ....... 13.0 ....... 6.5 ....... 2
24- or 36-in Temporary Pile Removal............. ....... 0.8 ....... 2.3 ....... 2.3 ....... 2.3 ....... 1.5 ....... 1.5 ....... 0.8 ....... 0.8
72-in Permanent Pile Installation \4\........... 5.7 0.7 5.7 0.7 5.7 0.7 4.3 0.5 4.3 0.5 4.3 0.5 4.3 0.5 4.3 0.5
-----------------------------------------------------------------------------------------------------------------------------------------------
Year 3 total hours.......................... 5.7 7.9 5.7 15.9 5.7 15.9 4.3 15.8 4.3 15.0 4.3 15.0 4.3 7.8 4.3 3.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Year 4--2029
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24- or 36-in Temporary Pile Installation........ ....... 2.5 ....... 5.5 ....... 5.5 ....... 6.0 ....... 5.5 ....... 5.5 ....... 2.5 ....... 2
24- or 36-in Temporary Pile Removal............. ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8 ....... .......
72-in Permanent Pile Installation \4\........... 7.2 0.8 12.9 1.5 12.9 1.5 12.9 1.5 12.9 1.5 11.5 1.3 11.5 1.3 5.7 0.7
-----------------------------------------------------------------------------------------------------------------------------------------------
Year 4 total hours.......................... 7.2 4.1 12.9 7.8 12.9 7.8 12.9 8.3 12.9 7.8 11.5 7.6 11.5 4.6 5.7 2.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Year 5--2030
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
24- or 36-in Temporary Pile Installation........ ....... 2.5 ....... 6.0 ....... 6.0 ....... 6.0 ....... 6.0 ....... 5.5 ....... 5.5 ....... 2.5
24- or 36-in Temporary Pile Removal............. ....... 0.8 ....... 0.8 ....... 1.5 ....... 1.5 ....... 0.8 ....... 0.8 ....... 0.8 ....... 0.8
72-in Permanent Pile Installation \4\........... 4.3 0.5 12.9 1.5 12.9 1.5 12.9 1.5 11.5 1.3 11.5 1.3 11.5 1.3 4.3 0.5
-----------------------------------------------------------------------------------------------------------------------------------------------
Year 5 total hours.............................. 4.3 3.8 12.9 8.3 12.9 8.3 12.9 8.3 11.5 8.1 11.5 7.6 11.5 7.6 4.3 3.8
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Duration estimates assume a single hammer active at any time and therefore likely overestimates of actual time needed due to simultaneous pile installation and removal;
\2\ Impact pile installation;
[[Page 85690]]
\3\ Vibratory pile installation or extraction;
\4\ To account for piles driven in water less than 3m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5
minutes of vibratory driving) each month. Numbers may not add exactly due to rounding.
[[Page 85691]]
Specific Geographic Region
The specific geographic region for this action encompasses the land
occupied by the POA, as well as the shoreline and waters extending from
the POA across Knik Arm, northeast towards Wasilla, and southwest
towards Fire Island and the Little Susitna River delta (figure 1).
Northern Cook Inlet bifurcates into Knik Arm to the north and
Turnagain Arm to the east. Knik Arm is generally considered to begin at
Point Woronzof, 7.4 km southwest of the POA. From Point Woronzof, Knik
Arm extends about 48 km in a north-northeasterly direction to the
mouths of the Matanuska and Knik rivers. At Cairn Point, just northeast
of the POA, Knik Arm narrows to about 2.4 km before widening to as much
as 8 km at the tidal flats northwest of Eagle Bay at the mouth of Eagle
River.
Knik Arm comprises narrow channels flanked by large tidal flats
composed of sand, mud, or gravel, depending upon location.
Approximately 60 percent of Knik Arm is exposed at Mean Lower Low Water
(MLLW). The intertidal (tidally influenced) areas of Knik Arm are
mudflats, both vegetated and unvegetated, which consist primarily of
fine, silt-sized glacial flour. Freshwater sources often are glacially
born waters, which carry high suspended sediment loads as well as a
variety of metals such as zinc, barium, mercury, and cadmium. Surface
waters in Cook Inlet typically carry high silt and sediment loads,
particularly during summer, making Knik Arm an extremely silty, turbid
waterbody with low visibility through the water column. The Matanuska
and Knik Rivers contribute the majority of freshwater and suspended
sediment into Knik Arm during summer. Smaller rivers and creeks also
enter along the sides of Knik Arm (U.S. Department of Transportation
and Port of Anchorage, 2008). During winter, sea, beach, and river ice
are dominant physical forces within Cook Inlet and Knik Arm. In upper
Cook Inlet, sea ice generally forms in October to November and
continues to develop through February or March (Moore et al., 2000).
Tides in Cook Inlet are semidiurnal, with two unequal high and low
tides per tidal day (tidal day = 24 hours, 50 minutes). Due to Knik
Arm's predominantly shallow depths and narrow widths, tides near
Anchorage are greater than those in the main body of Cook Inlet. The
tides at the POA have a mean range of about 8 m, and the maximum water
level has been measured at more than 12.5 m at the Anchorage station
(NMFS, 2015). Currents throughout Cook Inlet are strong and tidally
periodic, with average velocities ranging from 3 to 6 knots (5.6 to
11.1 kilometers (km)/hour (h)) (Sharma and Burrell, 1970). Maximum
current speeds in Knik Arm, observed during spring ebb tide, exceed 7
knots (13 km/h). These tides result in strong currents in alternating
directions through Knik Arm and a well-mixed water column. The
navigation harbor at the POA is a dredged basin in the natural tidal
flat. Sediment loads in upper Cook Inlet can be high; spring thaws
occur, and accompanying river discharges introduce considerable amounts
of sediment into the system (Ebersole and Raad, 2004). Natural
sedimentation processes act to continuously infill the dredged basin
each spring and summer.
The Municipality of Anchorage is located in the lower reaches of
Knik Arm of upper Cook Inlet (see figure 2-1 in the POA's application).
The POA sits on the industrial waterfront of Anchorage, just south of
Cairn Point and north of Ship Creek (lat. 61[deg]15' N, long.
149[deg]52' W; Seward Meridian) (figure 1). The POA's boundaries
currently occupy an area of approximately 0.52 km\2\ (figure 2). Other
commercial and industrial activities related to secured maritime
operations are located near the POA on Alaska Railroad Corporation
property immediately south of the POA, on approximately 0.45 km\2\ at a
similar elevation. The POA is located north of Ship Creek, an area that
experiences concentrated marine mammal activity during seasonal runs of
several salmon species. Ship Creek serves as an important recreational
fishing resource and is stocked twice each summer. Ship Creek flows
into Knik Arm through the Municipality of Anchorage industrial area.
Joint Base Elmendorf-Richardson (JBER) is located east of the POA,
approximately 30.5 m higher in elevation. The U.S. Army Defense Fuel
Support Point-Anchorage site is located east of the POA, south of JBER,
and north of Alaska Railroad Corporation property. The perpendicular
distance to the west bank directly across Knik Arm from the POA is
approximately 4.2 km. The distance from the POA (east side) to nearby
Port MacKenzie (west side) is approximately 4.9 km.
BILLING CODE 3510-22-P
[[Page 85692]]
[GRAPHIC] [TIFF OMITTED] TP28OC24.002
[[Page 85693]]
[GRAPHIC] [TIFF OMITTED] TP28OC24.003
BILLING CODE 3510-22-C
Detailed Description of the Specified Activities
As discussed previously, marine-side infrastructure and facilities
at the POA are in need of replacement because they are substantially
past their design life and in poor and deteriorating structural
condition. Those facilities include three general cargo terminals, two
petroleum terminals, a dry barge landing, and an upland sheet-pile-
supported storage and work area. To address deficiencies, the POA is
modernizing its marine terminals through the PAMP to enable safe,
reliable, and cost-effective Port operations. The PAMP will support
infrastructure resilience in the event of
[[Page 85694]]
a catastrophic natural disaster over a 75-year design life.
The PAMP is critical to maintaining food and fuel security for the
state. At the completion of the PAMP, the POA will have modern, safe,
resilient, and efficient facilities through which more than 90 percent
of Alaskans will continue to obtain food, supplies, tools, vehicles,
and fuel. The PAMP is divided into five separate phases; these phases
are designed to include projects that have independent utility yet
streamline agency permitting. The projects associated with the PAMP
include:
<bullet> Phase 1: Petroleum and Cement Terminal (PCT Phase 1 and 2)
and South Floating Dock (SFD) replacement;
<bullet> Phase 2A: North Extension Stabilization Phase 1 (NES1);
<bullet> Phase 2B: CTR;
<bullet> Phase 3: Petroleum, Oil and Lubricants Terminal 2
Replacement;
<bullet> Phase 4: North Extension Stabilization part 2; and
<bullet> Phase 5: Demolition of Terminal 3.
Phase 1 of the PAMP was completed in 2022. NMFS issued IHAs for
take incidental to the now completed PCT (Phase 1 and Phase 2; 85 FR
19294, April 6, 2020) and SFD projects (86 FR 50057, September 7,
2021). Phase 2A of the PAMP began in 2023; an IHA was issued for phase
one of the NES project (89 FR 2832, January 14, 2024) and in-water
construction associated with this project is planned for 2024. The
project discussed herein, CTR, is Phase 2B of the PAMP and is proposed
to begin onshore preparation in 2025 and in-water construction work in
2026.
The purpose of the CTR project is to replace the existing general
cargo docks. It would address deteriorating conditions of the existing
cargo facilities; improve operational safety and efficiency;
accommodate modern (existing and future) shipping operations; and
improve the resiliency of the POA to extreme seismic events, all while
sustaining ongoing cargo operations. This project is urgently needed
due to severe corrosion of the foundation piles and deteriorating
structural conditions at Terminals 1, 2, and 3. The existing terminals
are more than 50 years old and suffer from severe damage to the
foundation piles caused by corrosion and seismic forces. The piles have
exceeded their useful service life, and multiple engineering
investigations have highlighted the probability of wharf and trestle
structure failure during a future major seismic event. The remaining
service life of the cargo terminals is unknown. These facilities must
be replaced with new resilient terminals for the Port to continue to
meet its critical role serving Alaska's general cargo needs as well as
supporting national defense and military readiness capabilities.
The geographical isolation of Alaska and the POA's role as the
containerized logistic hub and distribution center for much of the
state make the cargo terminals a critical lifeline for the southcentral
region and Alaska. There are no other ports with the cargo capacity,
proximity to Alaska's population centers, and intermodal transportation
capabilities that can support the logistic missions sustained by the
POA, including commerce, national defense, and earthquake resiliency/
disaster response and recovery.
CTR Project Activities
The CTR project includes construction of new terminals T1 and T2,
which include planned wharves and access trestles. The two new
terminals would be located 140 feet (ft) (42.7 meters (m)) seaward of
the existing T1, T2, and T3. It is anticipated that this more seaward
location of the new terminals will reduce sedimentation, improve room
for handling of berthing ships, and allow construction of the new
terminals while the existing terminals remain in use. CTR also includes
demolition of the existing Petroleum, Oil, and Lubricants Terminal 1
(POL1) and general cargo terminals (T1, T2, and T3).
The southernmost end of the new T1 and T2 would be approximately
1.4 km (0.9 mile (mi)) north of Ship Creek. Construction of the Project
will include completion of the following components:
<bullet> Component 1. Onshore ground improvement shoreline
stabilization (2025)
<bullet> Component 2. Shoreline expansion and protection (2026)
<bullet> Component 3. General cargo terminals (new Terminals 1 and
2) construction (2026-2031)
<bullet> Component 4. Demolition of existing terminals (POL1 and
general cargo terminals (existing Terminals 1, 2, and 3)) (2026-2031)
<bullet> Component 5. Onshore utilities and storm drain outfall
replacement (2030-2031)
Of these activities, only Components 3 and 4 include construction
work that would occur in the water, and therefore, these would be the
only components of the project expected to potentially impact marine
mammals.
Landside Activities
Landside activities include work which takes place ``in the dry,''
either above the high tide line or in the intertidal zone but de-
watered. These activities include shoreline stabilization and
protection as well as placement of onshore utilities and decking
components.
Ground Improvement Shoreline Stabilization--A ground improvement
technique, such as deep soil mixing (DSM), or a similar technique would
be used to stabilize the shoreline. DSM and similar techniques
mechanically mix weak soils with a cement binder causing the soils to
behave more like soft rock. This process is used to create foundations
for buildings and roads and is used in earthquake-prone areas to
prevent soil liquefaction. Soil improvements at trestle abutments, and
potentially between the abutments, will mitigate the potential for
seismic-induced slope failure that could result in catastrophic
structural failure.
The first stage of construction would include installation of soil
improvements in the five locations where the access trestles meet the
beach to provide geotechnical stability to the embankment. Centered at
each of the five trestle abutments, the ground improvement technique
would create approximately 200- by 96-ft (61- by 29-m) blocks of
treated soil extending from the surface to the top of the clay layer
approximately 85-ft (25.9-m) deep (see figure 1-2 of the POA's
application). The size of the block is designed to create enough
contact area with the clay layer to restrain and significantly reduce
the overall ground movements of the liquefiable soils surrounding the
trestle abutment. If deemed necessary for geotechnical stability,
ground improvements would extend along the embankment in areas between
the abutments.
During construction, a temporary soil work pad would be constructed
at each of the five trestles to provide a level temporary work surface.
The ground improvement panels/columns would extend approximately 100
feet (ft) (30.5-m) seaward and shoreward of the crest of the slope and
approximately 30 ft (9-m) to either side of the trestle structure.
Temporary armoring will protect the work pad from water forces while in
use. After completion of the ground improvement work, the temporary
construction work pads will be removed and the foreshore graded and
armored.
Shoreline Expansion and Protection--The existing shoreline behind
the existing Terminals 1, 2, and 3 is irregular, with two areas where
the shoreline is located about 100 ft (30-m) to the east of the typical
shoreline (see figure 1-3 of the POA's application). These areas would
be excavated to remove deposited silts before the areas
[[Page 85695]]
are then filled with more dense, stable materials such as clean gravel
and rock. The filled area would provide a consistent shoreline and
additional container storage area.
Excavation for the CTR project would be limited to removal of
materials that are above the high-water line or below the high-water
line in a dewatered state. Sea-based dredging of materials under water
will not take place as part of this project.
After ground improvement work and shoreline expansion have been
completed, the slope along the shore would be secured with armor stone
placed over the clean gravel and rock fill. Placement of armor rock
requires good visibility of the shore as each rock is placed carefully
to interlock with surrounding armor rock. It is therefore anticipated
that placement of most armor rock, filter rock, and granular fill will
occur in the dry at low tide levels; however, some placement of armor
rock, filter rock, and granular fill may occur in shallow water (i.e.,
less than 3 m deep). After placement of armor rock, the top of the fill
will be paved to match the existing backland pavements.
Onshore utilities and storm drain outfall replacement--The
replacement of onshore utilities will involve construction on land and
replacement of utilities above the high tide line, on land. Similarly,
the storm drain outfall replacement will involve construction on land
and replacement of four outfall pipes above the high tide line. No in-
water work is proposed as a part of this component.
Ground improvement shoreline stabilization, shoreline expansion and
protection, and onshore utilities and storm drain outfall replacement
activities would take place on land or in the dry. While a minimal
amount of fill and armor rock placement may occur in water, this
activity would not be expected to impact marine mammals. Therefore,
take of marine mammals related to these activities is not anticipated
or proposed to be authorized, and it will not be considered further in
this proposed rulemaking.
In-Water Construction
New terminals T1 and T2 would be constructed as seismically
resilient adjoining terminals on a continuous berthline with mooring
features and appurtenances as required to support safe ship mooring for
lift-on/lift-off and roll-on/roll-off related cargo handling
operations. The new T1 wharf would be 870 ft x 120 ft (265- x 37-m)
with two 36-ft-wide (11-m) trestles of varying length. The new T2 wharf
would be 932 ft x 120 ft (284- x 37-m) with two 259-ft- long x 54-ft-
wide (79- x 16.5-m) trestles and one 259-ft-long x 76-ft-wide (79- x
23-m) trestle. Both T1 and T2 would be constructed using 48- and 72-in-
diameter (121- and 183-centimeter (cm), respectively) steel piles. The
48-in-diameter piles will be installed in the dry.
Both new terminals would be designed to accommodate lift-on/lift-
off container operations serviced by rail-mounted ship-to-shore cranes.
Structural, in-deck, and surface features to support operational
interface for three 100-gauge rail mounted gantry cranes, and
associated appurtenances along with an on-terminal combination
stevedore-operations building, would be included on the wharf.
Additionally, T2 would be designed to support roll-on/roll-off
container operations and other multi-purpose cargo functions. The
reinforced concrete deck structure for both new terminals and all new
access trestles would be designed to 1,000 pound per square foot load
capacity. Construction would also include installation of power,
lighting, communications, and signal infrastructure to terminal and
onshore electrically powered features; potable water service including
ship's water; and fire-flow water for terminal-related operations. The
on-terminal stevedore-operations building would also be constructed
with a connection to the onshore, existing public utility
infrastructure.
In addition to these permanent structures, temporary work including
temporary pile installation and removal would be required to support
construction. Temporary piles would likely be 36-in-diameter (91-cm)
steel; however, 24-in (61-cm) steel piles may be used in place of some
of the larger temporary piles. Various work boats and barges would be
utilized and would be moored at or in the immediate vicinity of the
project, but these vessels are not expected to increase overall noise
levels at the POA above existing operational levels. No thrusters or
other dynamic positioning methods will be used during pile driving
activities.
Construction of each terminal would require installation and
removal of temporary steel pipe piles, including template piles, and
installation of permanent steel pipe piles. Pile installation would
occur in water depths that range from a few feet or dry (dewatered)
conditions nearest the shore to approximately 20 meters (70 ft) at the
outer face of the wharves, depending on tidal stage; the mean diurnal
tide range at the POA is approximately 8.0 meters (26 ft; NOAA 2015).
Concurrent Activities--In-water construction activities would occur
at multiple locations across the project site simultaneously; the POA
anticipates that two ``spreads'' (a construction crew with crane and
pile driving hammer) would be on site and working throughout the
construction season, with a third ``spread'' present on some days. Of
the two regular spreads, one would be designated for permanent (72-in)
piles and one for temporary (24-in or 36-in) piles. Each spread would
operate a single hammer at a time (impact or vibratory), with no more
than two vibratory hammers simultaneously active in-water at any given
time. It is not expected that three piles would be driven concurrently,
and this scenario is not addressed further in this analysis. The only
combinations of vibratory hammers that could be used simultaneously
would be for installation of an attenuated (through use of a bubble
curtain; see Proposed Mitigation later in this notice) 72-in pile and
an attenuated temporary pile, an attenuated 72-in pile and an
unattenuated temporary pile, or two temporary piles. There would be no
simultaneous driving of unattenuated 72-in piles in water. Simultaneous
use of two hammers would increase production rates.
Duration of active hammer use is anticipated to be brief each day
(see table 1), and it is, therefore, anticipated that overlap in use of
hammers would be uncommon. Pile installation and removal would occur
intermittently over the work period, for durations of minutes to hours
at a time. Use of two simultaneous hammers would serve to reduce the
overall duration of in-water pile installation and removal during each
construction season. One construction crane would likely be based on a
floating work barge, and one would likely be based on land or on an
access trestle. Table 3 provides a summary of concurrent pile driving
scenarios.
[[Page 85696]]
Table 3--Potential Concurrent Driving Scenarios That Could Occur During CTR Construction
----------------------------------------------------------------------------------------------------------------
Equipment type and quantity Pile type and size Construction months
----------------------------------------------------------------------------------------------------------------
Vibratory x 2........................... 2 x 36-in steel pipe \1\.................. April-July.
Vibratory, Impact....................... 2 x 72-in steel pipe \2\ OR 1 x 72-in April-November.
steel pipe \2\ (impact) and
1 x 36-in steel pipe (vibratory)..........
----------------------------------------------------------------------------------------------------------------
\1\ POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to
have larger ensonified areas, we have used these piles in our analyses of concurrent activities;
\2\ All 72-in piles driven concurrently will be attenuated.
Pile Installation and Removal--Vibratory and impact hammers would
be used for the installation of 72-in (182-cm) permanent piles.
Vibratory hammers would be used for installation and removal of 24-
(61-cm) and or 36-in (91-cm) temporary piles; however, if obstructions
are encountered during installation, impact driving may be necessary.
Installation and removal of piles in the dry would be maximized as much
as feasible, depending on construction sequencing and tide heights.
However, the exact number of piles that may be installed and removed in
the dry is unknown (see table 1 for estimates and numbers of piles
analyzed for in-water construction activities). Impact and vibratory
pile driving activities conducted in the dry are not expected to impact
marine mammals and therefore, are not discussed further in this rule.
Pile Cutting--A majority of in-water temporary piles (approximately
90 percent) would be cut off at the mudline and remain in place,
removed via direct pulling, or would remain in place intact (without
cutting). Temporary piles that conflict with construction or operations
or that can be removed in the dry would be removed. Leaving piles in
place below the mudline supports stability of the soil. Also, many of
the existing T1 and T2 piles are corroded and may break during removal,
with the lower part remaining in place. The existing structure is
closer to shore than new construction, and many piles can be cut or
removed in the dry when their location is dewatered.
The number of piles that would be cut or remain in place would be
maximized as feasible; however, the exact number of piles that may be
cut or can remain in place is unknown (see table 1 for best estimates
of piles to be removed). While the exact method of pile cutting is at
the discretion of the construction contractor, any methodology
considered for cutting and removing the piles would account for worker
safety, constructability, and minimization of potential acoustic
impacts that the operation may have on marine mammals. Potential
methods of underwater cutting include ultrathermic cutting, pile
clippers or wire-saws.
Underwater ultrathermic cutting is performed by commercial divers
using hand-held equipment to cut or melt through ferrous and non-
ferrous metals. These systems operate through a torch-like process,
initiated by applying a melting amperage to a steel tube packed with
alloy steel rods, sometimes mixed with aluminum rods to increase the
heat output. In the hands of skilled commercial divers, underwater
ultrathermic cutting is reputed to be relatively fast and efficient,
cutting through approximately 2 to 4 inches (5 to 10 cm) per minute,
depending upon the number of divers deployed. This efficacy may be
constrained by the requirement to secure the severed piles from falling
into the inlet to prevent an extreme hazard to the diver cutting the
piles. Tidally driven currents in Cook Inlet may limit dive times to
approximately 2 to 3 hours per high- and low-tide event, depending upon
the tide cycle and the ability of divers to efficiently perform the
cutting task while holding position during high current periods. This
activity is not considered to produce sound.
Pile clipping and underwater sawing generate noise that is
typically non-impulsive, low-level, and short duration (typically less
than 15 seconds per pile) (NAVFAC SW, 2020). Potential pile cutting
methodologies are not anticipated to result in incidental take of
marine mammals because they are either above water, do not last for
sufficient duration to present the reasonable potential for disruption
of behavioral patterns, do not produce sound levels likely to result in
marine mammal harassment, or some combination of the above. Impacts on
marine mammals from pile cutting are therefore considered de minimis
and NMFS is not proposing to authorize incidental take from this
activity.
Demolition of Existing Terminals--Once the new T1, T2, and
petroleum products transfer system are complete and operational, any
remaining existing T1, T2, and POL1 platforms, wharves, and trestles
would be dismantled (see figure 1-5 of the POA's application). Existing
and most temporary piles would be cut and removed, removed via
vibratory extraction or direct pull, or left in place. The selection of
construction equipment by the contractor, including cranes and barges,
would determine the plans and sequencing for demolition. Portions of
the existing terminals may be used for construction phasing and as
support platforms for ongoing new construction, as feasible.
T3 may be partially demolished during Phase 2B construction of T1
and T2, especially where the existing infrastructure may interfere with
new construction. Elements of T3 that remain after Phase 2B is complete
would remain in place until Phase 5, when they would be removed at that
time.
Demolition would take place above the water, and demolished
decking, pipes, and other superstructure materials would be contained
before they fall into the water following best management practices.
Demolished materials would be removed by barge or truck. Because work
would take place out of water with best management practices in place
to limit any release of material into Cook Inlet, in addition to
cutting off or leaving existing piles in place, impacts on marine
mammals from demolition of the existing terminals are considered de
minimis and NMFS is not proposing to authorize incidental take from
this activity.
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 Specified Geographical Region
There are seven species, comprising 9 stocks, of marine mammals
that may be found in upper Cook Inlet during the proposed construction
and demolition activities. Sections 3 and 4 of the POA's application
and request for regulations 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
[[Page 85697]]
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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 4 lists all species or stocks for which take is likely and
proposed to be authorized for the specified activities 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'' (16
U.S.C. 1362(20)). While no serious injury or mortality is anticipated
or proposed to be authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species or stocks and other threats.
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' U.S. Alaska and Pacific SARs (e.g., Carretta, et al., 2023; Young
et al., 2023, 2024). Values presented in table 4 are the most recent
available at the time of publication (including from the draft 2023
SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports</a>. The most recent abundance estimate for CIBWs is available from
Goetz et al. (2023) and available online at <a href="https://www.fisheries.noaa.gov/feature-story/new-abundance-estimate-endangered-cook-inlet-beluga-whales">https://www.fisheries.noaa.gov/feature-story/new-abundance-estimate-endangered-cook-inlet-beluga-whales</a>.
Table 4--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance
ESA/ MMPA status; Nbest, (CV, Nmin, Annual M/
Common name Scientific name MMPA stock strategic (Y/N) \1\ most recent abundance PBR SI \3\
survey) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale..................... Eschrichtius robustus. Eastern N Pacific..... -/-; N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Humpback whale................. Megaptera novaeangliae Hawaii................ -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific.. T, D, Y N/A (N/A, N/A, 2006). UND \5\ 0.57
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
Killer whale................... Orcinus orca.......... Eastern North Pacific -/-; N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019).
Eastern North Pacific -/-; N 587 (N/A, 587, 2012). 5.9 0.8
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
Family Monodontidae:
Beluga whale................... Delphinapterus leucas. Cook Inlet............ E/D; Y 331 (0.076, 290, 0.53 0
2022) \4\.
Family Phocoenidae (porpoises):
Harbor porpoise................ Phocoena phocoena..... Gulf of Alaska........ -/-; Y 31,046 (0.214, N/A, UND \5\ 72
1998).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
sea lions):
Steller sea lion............... Eumetopias jubatus.... Western............... E/D; Y 49,837 (N/A, 49,837 299 267
2022).
Family Phocidae (earless seals):
Harbor seal.................... Phoca vitulina........ Cook Inlet/Shelikof -/-; N 28,411 (N/A, 26,907, 807 107
Strait. 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a> assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ This abundance estimate is from Goetz et al. (2023); which was published after the most recent CIBW SAR (Young et al., 2023).
\5\ UND means undetermined.
[[Page 85698]]
As indicated above, all seven species (nine managed stocks) in
table 4 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. Minke whales
(Balaenoptera acutorostrata) and Dall's porpoises (Phocoenoides dalli)
also occur in Cook Inlet; however, the spatial occurrence of these
species is such that take is not likely to occur, and they are not
discussed further beyond the explanation provided here. Data from the
Alaska Marine Mammal Stranding Network database (NMFS, unpublished
data) provide additional support for these determinations. From 2011 to
2020, only one minke whale and one Dall's porpoise were documented as
stranded in the portion of Cook Inlet north of Point Possession. Both
were dead upon discovery; it is unknown if they were alive upon their
entry into upper Cook Inlet or drifted into the area with the tides.
With very few exceptions, minke whales and Dall's porpoises do not
occur in upper Cook Inlet, and therefore, take of these species is
considered unlikely.
In addition to what is included in sections 3 and 4 of the POA's
application (<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization">https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization</a>), the SARs (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>), and NMFS'
website, we provide further detail below informing the baseline for
species likely to be found in the project area (e.g., information
regarding current UMEs and known important habitat areas, such as
Biologically Important Areas (BIAs; <a href="https://oceannoise.noaa.gov/biologically-important-areas">https://oceannoise.noaa.gov/biologically-important-areas</a>) (Van Parijs et al., 2015)).
Gray Whale
Gray whales are infrequent visitors to Cook Inlet but can be
seasonally present during spring and fall in the lower inlet (Bureau of
Ocean Energy Management (BOEM), 2021). Migrating gray whales pass
through the lower inlet during their spring and fall migrations to and
from their primary summer feeding areas in the Bering, Chukchi, and
Beaufort seas (Swartz, 2018; Silber et al., 2021; BOEM, 2021). There
are no BIAs for gray whales in Cook Inlet.
Gray whales are rarely documented in upper Cook Inlet and in the
project area. Gray whales were not documented during POA construction
or scientific monitoring from 2005 to 2011 or during 2016 (Prevel-Ramos
et al., 2006; Markowitz and McGuire, 2007; Cornick and Saxon-Kendall,
2008, 2009; Cornick et al., 2010, 2011; Integrated Concepts and
Research Corporation (ICRC), 2009, 2010, 2011, 2012; Cornick and
Pinney, 2011; Cornick and Seagars, 2016); however, one gray whale was
observed near Port MacKenzie during 2020 PCT construction (61 North
(61N) Environmental, 2021) and a second whale was observed off of Ship
Creek during 2021 PCT construction monitoring (61N Environmental,
2022a, Easley-Appleyard and Leonard, 2022). The whale observed in 2020
is believed to be the same whale that later stranded in the Twentymile
River, at the eastern end of Turnagain Arm, approximately 80 km
southeast of Knik Arm. There was no indication that work at the PCT had
any effect on the animal, which was reported to be in ``fair to poor''
condition during evaluation (see <a href="https://www.fisheries.noaa.gov/feature-story/alaska-gray-whale-ume-update-twentymile-river-whale-likely-one-twelve-dead-gray-whales">https://www.fisheries.noaa.gov/feature-story/alaska-gray-whale-ume-update-twentymile-river-whale-likely-one-twelve-dead-gray-whales</a> for more information). No gray
whales were observed during POA's transitional dredging or SFD
construction monitoring from May to August, 2022 (61N Environmental,
2022b, 2022c).
Under the MMPA, a UME is defined as ``a stranding that is
unexpected; involves a significant die-off of any marine mammal
population; and demands immediate response'' (16 U.S.C. 1421h(6)). A
recently closed UME for gray whales along the West Coast and in Alaska
occurred from December 17, 2018 through November 9, 2023. During that
time, 146 gray whales stranded off the coast of Alaska. The
investigative team concluded that the preliminary cause of the UME was
localized ecosystem changes in the whale's Subarctic and Arctic feeding
areas that led to changes in food, malnutrition, decreased birth rates,
and increased mortality (see <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2023-gray-whale-unusual-mortality-event-along-west-coast-and">https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2023-gray-whale-unusual-mortality-event-along-west-coast-and</a> for more information). Given the changing
environment in the polar regions due to climate change, there is
potential for changes to gray whale behavior and distribution in the
near future.
Humpback Whale
The 2022 Alaska and Pacific SARs described a revised stock
structure for humpback whales, which modifies the previous stocks
designated under the MMPA to align more closely with the ESA-designated
distinct population segments (DPSs) (Carretta et al., 2023; Young et
al., 2023). Specifically, the three previous North Pacific humpback
whale stocks (Central and Western North Pacific stocks and a CA/OR/WA
stock) were replaced by five stocks, largely corresponding with the
ESA-designated DPSs. These include Western North Pacific and Hawaii
stocks and a Central America/Southern Mexico-CA/OR/WA stock (which
corresponds with the Central America DPS). The remaining two stocks,
corresponding with the Mexico DPS, are the Mainland Mexico-CA/OR/WA and
Mexico-North Pacific stocks (Carretta et al., 2023; Young et al.,
2023). The former stock is expected to occur along the west coast from
California to southern British Columbia, while the latter stock may
occur across the Pacific, from northern British Columbia through the
Gulf of Alaska and Aleutian Islands/Bering Sea region to Russia.
The Hawaii stock consists of one demographically independent
population (DIP) (Hawaii--Southeast Alaska/Northern British Columbia
DIP) and the Hawaii--North Pacific unit, which may or may not be
composed of multiple DIPs (Wade et al., 2021). The DIP and unit are
managed as a single stock at this time, due to the lack of data
available to separately assess them and lack of compelling conservation
benefit to managing them separately (NMFS, 2019, 2022b, 2023). The DIP
is delineated based on two strong lines of evidence: genetics and
movement data (Wade et al., 2021). Whales in the Hawaii--Southeast
Alaska/Northern British Columbia DIP winter off Hawaii and largely
summer in Southeast Alaska and Northern British Columbia (Wade et al.,
2021). The group of whales that migrate from Russia, western Alaska
(Bering Sea and Aleutian Islands), and central Alaska (Gulf of Alaska
excluding Southeast Alaska) to Hawaii have been delineated as the
Hawaii-North Pacific unit (Wade et al., 2021). There are a small number
of whales that migrate between Hawaii and southern British Columbia/
Washington, but current data and analyses do not provide a clear
understanding of which unit these whales belong to (Wade et al., 2021;
Carretta et al., 2023; Young et al., 2023).
The Mexico-North Pacific stock is likely composed of multiple DIPs,
based on movement data (Martien et al., 2021; Wade, 2021; Wade et al.,
2021). However, because currently available data and analyses are not
sufficient to delineate or assess DIPs within the unit, it was
designated as a single stock (NMFS, 2019, 2022c, 2023). Whales in this
stock winter off Mexico and the Revillagigedo Archipelago and summer
primarily in Alaska waters (Martien et al., 2021; Carretta et al.,
2023; Young et al., 2023).
[[Page 85699]]
The most comprehensive photo-identification data available suggest
that approximately 89 percent of all humpback whales in the Gulf of
Alaska are members of the Hawaii stock, 11 percent are from the Mexico-
North Pacific stock, and less than 1 percent are from the Western North
Pacific stock (Wade, 2021). Members of different stocks are known to
intermix in feeding grounds.
On October 9, 2019, NMFS proposed to designate critical habitat for
the Western North Pacific, Mexico, and Central America DPSs of humpback
whales (84 FR 54354). NMFS issued a final rule on April 21, 2021 to
designate critical habitat for ESA-listed humpback whales pursuant to
section 4 of the ESA (86 FR 21082). There is no designated critical
habitat for humpback whales in or near the Project area (86 FR 21082,
April 21, 2021), nor does the project overlap with any known BIAs.
Humpback whales are encountered regularly in lower Cook Inlet and
occasionally in mid-Cook Inlet; however, sightings are rare in upper
Cook Inlet (e.g., Witteveen et al., 2011). During aerial surveys
conducted in summers between 2005 and 2012, Shelden et al. (2013)
reported dozens of sightings in lower Cook Inlet, a handful of
sightings in the vicinity of Anchor Point and in lower Cook Inlet, and
no sightings north of 60[deg] N latitude. NMFS changed to a biennial
survey schedule starting in 2014 after analysis showed there would be
little reduction in the ability to detect a trend given the current
growth rate of the population (Hobbs, 2013). No survey took place in
2020. Instead, consecutive surveys took place in 2021 and 2022 (Shelden
et al., 2022). During the 2014-2022 aerial surveys, sightings of
humpback whales were recorded in lower Cook Inlet and mid-Cook Inlet,
but none were observed in upper Cook Inlet (Shelden et al., 2015b,
2017, 2019, 2022). Vessel-based observers participating in the Apache
Corporation's 2014 survey operations recorded three humpback whale
sightings near Moose Point in upper Cook Inlet and two sightings near
Anchor Point, while aerial and land-based observers recorded no
humpback whale sightings, including in the upper inlet (Lomac-MacNair
et al., 2014). Observers monitoring waters between Point Campbell and
Fire Island during summer and fall 2011 and spring and summer 2012
recorded no humpback whale sightings (Brueggeman et al., 2013).
Monitoring of Turnagain Arm during ice-free months between 2006 and
2014 yielded one humpback whale sighting (McGuire, unpublished data,
cited in LGL Alaska Research Associates, Inc., and DOWL, 2015).
There have been few sightings of humpback whales in the vicinity of
the proposed project area. Humpback whales were not documented during
POA construction or scientific monitoring from 2005 to 2011, in 2016,
or during 2020 (Prevel-Ramos et al., 2006; Markowitz and McGuire, 2007;
Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010, 2011;
ICRC, 2009, 2010, 2011, 2012; Cornick and Pinney, 2011; Cornick and
Seagars, 2016; 61N Environmental, 2021). Observers monitoring the Ship
Creek Small Boat Launch from August 23 to September 11, 2017 recorded
two sightings, each of a single humpback whale, which was presumed to
be the same individual (POA, 2017). One other humpback whale sighting
has been recorded for the immediate vicinity of the project area. This
event involved a stranded whale that was sighted near a number of
locations in upper Cook Inlet before washing ashore at Kincaid Park in
2017; it is unclear as to whether the humpback whale was alive or
deceased upon entering Cook Inlet waters. Another juvenile humpback
stranded in Turnagain Arm in April 2019 near mile 86 of the Seward
Highway. One additional humpback whale was observed in July during 2022
transitional dredging monitoring (61N Environmental, 2022c). No
humpback whales were observed during the 2020 to 2021 PCT construction
monitoring, the NMFS marine mammal monitoring, or the 2022 SFD
construction monitoring from April to June (61N Environmental, 2021,
2022a, 2022b, 2022c; Easley-Appleyard and Leonard, 2022).
Killer Whale
Killer whales are rare in Cook Inlet, and there are no known BIAs
for this species in Cook Inlet. Most sightings of killer whales in the
area are in lower Cook Inlet (Shelden et al., 2013). The infrequent
sightings of killer whales that are reported in upper Cook Inlet tend
to occur when their primary prey (anadromous fish for resident killer
whales and beluga whales for transient killer whales) are also in the
area (Shelden et al., 2003). During CIBW aerial surveys between 1993
and 2012, killer whales were sighted in lower Cook Inlet 17 times, with
a total of 70 animals (Shelden et al., 2013); no killer whales were
observed in upper Cook Inlet during this time. Surveys over 20 years by
Shelden et al. (2003) documented an increase in CIBW sightings and
strandings in upper Cook Inlet beginning in the early 1990s. Several of
these sightings and strandings reported evidence of killer whale
predation on CIBWs. The pod sizes of killer whales preying on CIBWs
ranged from one to six individuals (Shelden et al., 2003). Passive
acoustic monitoring efforts throughout Cook Inlet documented killer
whales at the Beluga River, Kenai River, and Homer Spit, although they
were not encountered within Knik Arm (Castellote et al., 2016). These
detections were likely resident killer whales. Transient killer whales
likely have not been acoustically detected due to their propensity to
move quietly through waters to track prey (Small, 2010; Lammers et al.,
2013).
Few killer whales, if any, are expected to approach or be in the
vicinity of the proposed project area. No killer whales were spotted in
the vicinity of the POA during surveys by Funk et al. (2005), Ireland
et al. (2005), or Brueggeman et al. (2007, 2008a, 2008b). Killer whales
have also not been documented during any POA construction or scientific
monitoring from 2005 to 2011, in 2016, or in 2020 (Prevel-Ramos et al.,
2006; Markowitz and McGuire, 2007; Cornick and Saxon-Kendall, 2008;
ICRC, 2009, 2010, 2011, 2012; Cornick et al., 2010, 2011; Cornick and
Pinney, 2011; Cornick and Seagars, 2016; 61N Environmental, 2021). Two
killer whales, one male and one juvenile of unknown sex, were sighted
offshore of Point Woronzof in September 2021 during PCT Phase 2
construction monitoring (61N Environmental, 2022a). The pair of killer
whales moved up Knik Arm, reversed direction near Cairn Point, and
moved southwest out of Knik Arm toward the open water of Upper Cook
Inlet. No killer whales were sighted during the 2021 NMFS marine mammal
monitoring or the 2022 transitional dredging and SFD construction
monitoring that occurred between May and June 2022 (61N Environmental,
2022b, 2022c; Easley-Appleyard and Leonard, 2022).
Beluga Whale
Five stocks of beluga whales are recognized in Alaska: the Beaufort
Sea stock, eastern Chukchi Sea stock, eastern Bering Sea stock, Bristol
Bay stock, and Cook Inlet stock (Young et al., 2023). The Cook Inlet
stock is geographically and genetically isolated from the other stocks
(O'Corry-Crowe et al., 1997; Laidre et al., 2000) and resides year-
round in Cook Inlet (Laidre et al., 2000; Castellote et al., 2020).
Only the CIBW stock inhabits the proposed project area. CIBWs were
designated as a DPS and listed as endangered under the ESA in October
2008 (73 FR 62919, October 10, 2008).
[[Page 85700]]
On June 15, 2023, NMFS released an updated abundance estimate for
CIBWs (Goetz et al., 2023) that incorporates aerial survey data from
June 2021 and 2022, which represents an update from the most recent SAR
(Young et al., 2023) and suggest that the CIBW population is stable or
may be slightly increasing. The methodology in the 2023 report is the
same as that used for NMFS's SARs (Young et al. 2023) and incorporates
the same time-series of data from previous years. The only change was
the inclusion of more recent data from 2021 and 2022 surveys; the 2021
data collection efforts were delayed from 2020 due to COVID-19. Goetz
et al. (2023) estimated that the population size is currently between
290 and 386, with a median best estimate of 331. We have determined
that Goetz et al. (2023) represents the most recent and best available
science.
Goetz et al. (2023) also present an analysis of population trends
for the most recent 10-year period (2012-2022). The addition of data
from the 2021 and 2022 survey years in the analysis resulted in a 65.1
percent probability that the CIBW population is now increasing at 0.9
percent per year (95 percent prediction interval of -3 to 5.7 percent).
This increase drops slightly to 0.2 percent per year (95 percent
prediction interval of -1.8 to 2.6 percent) with a 60 percent
probability that the CIBW population is increasing more than 1 percent
per year when data from 2021, which had limited survey coverage due to
poor weather, are excluded from the analysis. Median group size
estimates in 2021 and 2022 were 34 and 15, respectively (Goetz et al.,
2023). NMFS has determined that the carrying capacity of Cook Inlet is
1,300 CIBWs (65 FR 34590, May 31, 2000) based on historical CIBW
abundance estimated by Calkins (1989). Additional information may be
found in NMFS' 2023 report on the abundance and trend of CIBWs in Cook
Inlet in June 2021 and June 2022, available online at <a href="https://www.fisheries.noaa.gov/resource/document/abundance-and-trend-belugas-delphinapterus-leucas-cook-inlet-alaska-june-2021-and">https://www.fisheries.noaa.gov/resource/document/abundance-and-trend-belugas-delphinapterus-leucas-cook-inlet-alaska-june-2021-and</a>.
Live stranding events of CIBWs have been regularly observed in
upper Cook Inlet. This can occur when an individual or group of
individuals strands as the tide recedes. Most live strandings have
occurred in Knik Arm and Turnagain Arm, which are shallow and have
large tidal ranges, strong currents, and extensive mudflats. Most
whales involved in a live stranding event survive, although some
associated deaths may not be observed if the whales die later from
live-stranding-related injuries (Vos and Shelden, 2005; Burek-
Huntington et al., 2015). Between 2014 and 2018, there were reports of
approximately 79 CIBWs involved in 3 known live stranding events plus 1
suspected live stranding event with two associated deaths reported
(NMFS, 2016b; NMFS, unpublished data; Muto et al., 2020). In 2014,
necropsy results from two whales found in Turnagain Arm suggested that
a live stranding event contributed to their deaths as both had
aspirated mud and water. No live stranding events were reported prior
to the discovery of these dead whales suggesting that not all live
stranding events are observed.
Another source of CIBW mortality in Cook Inlet is predation by
transient-type (mammal-eating) killer whales (NMFS, 2016b; Shelden et
al., 2003). No human-caused mortality or serious injury of CIBWs
through interactions with commercial, recreational, and subsistence
fisheries or because of other human-caused events (e.g., entanglement
in marine debris, ship strikes) has been recently documented, and
subsistence harvesting of CIBWs has not occurred since 2008 (NMFS,
2008b).
Recovery Plan. The Final Recovery Plan for CIBW was published in
the Federal Register on January 5, 2017 (82 FR 1325), available online
at <a href="https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas">https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas</a>.
In its Recovery Plan (82 FR 1325, January 5, 2017), NMFS identified
several potential threats to CIBWs, including: (1) high concern:
catastrophic events (e.g., natural disasters, spills, mass strandings),
cumulative effects of multiple stressors, and noise; (2) medium
concern: disease agents (e.g., pathogens, parasites, and harmful algal
blooms), habitat loss or degradation, reduction in prey, and prohibited
take (e.g., entanglements, strikes, poaching or intentional harassment,
and close approaches by private vessels); and (3) low concern:
pollution, predation, and subsistence harvest. The recovery plan did
not treat climate change as a distinct threat but rather as a
consideration in the threats of high and medium concern. Other
potential threats most likely to result in direct human-caused
mortality or serious injury of this stock include vessel strikes.
Critical Habitat. On April 11, 2011, NMFS designated two areas of
critical habitat for CIBW (76 FR 20179). The designation includes 7,800
km\2\ of marine and estuarine habitat within Cook Inlet, encompassing
approximately 1,909 km\2\ in Area 1 and 5,891 km\2\ in Area 2 (see
figure 1 in 76 FR 20179). Area 1 of the CIBW critical habitat
encompasses all marine waters of Cook Inlet north of a line connecting
Point Possession (lat. 61.04[deg] N, long. 150.37[deg] W) and the mouth
of Three Mile Creek (lat. 61.08.55[deg] N, long. 151.04.40[deg] W),
including waters of the Susitna, Little Susitna, and Chickaloon Rivers
below mean higher high water. From spring through fall, Area 1 critical
habitat has the highest concentration of CIBWs due to its important
foraging and calving habitat. Area 2 critical habitat has a lower
concentration of CIBWs in spring and summer but is used by CIBWs in
fall and winter. Critical habitat does not include two areas of
military usage: the Eagle River Flats Range on Fort Richardson and
military lands of JBER between Mean Higher High Water and MHW.
Additionally, the POA, adjacent navigation channel, and turning basin
(approximately 6.84 km\2\) were excluded from the critical habitat
designation due to national security reasons (76 FR 20180, April 11,
2011). The POA exclusion area is within Area 1, however, marine mammal
monitoring results from the POA suggest that this exclusion area is not
a particularly important feeding or calving area. CIBWs have been
occasionally documented to forage around Ship Creek (south of the POA)
but are typically transiting through the area to other, potentially
richer, foraging areas to the north (e.g., Six Mile Creek, Eagle River,
Eklutna River) (e.g., 61N Environmental, 2021, 2022a, 2022b, 2022c,
Easley-Appleyard and Leonard, 2022). These locations contain
predictable salmon runs, an important food source for CIBWs, and the
timing of these runs has been correlated with CIBW movements into the
upper reaches of Knik Arm (Ezer et al., 2013). More information on CIBW
critical habitat can be found at <a href="https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale">https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale</a>.
The designation identified the following Primary Constituent
Elements (PCE), essential features important to the conservation of the
CIBW:
(1) Intertidal and subtidal waters of Cook Inlet with depths of
less than 9 m (MLLW) and within 8 km of high- and medium-flow
anadromous fish streams;
(2) Primary prey species, including four of the five species of
Pacific salmon (chum (Oncorhynchus keta), sockeye (Oncorhynchus nerka),
Chinook (Oncorhynchus tshawytscha), and coho (Oncorhynchus kisutch)),
Pacific eulachon (Thaleichthys pacificus), Pacific cod (Gadus
macrocephalus), walleye pollock (Gadus chalcogrammus), saffron cod
(Eleginus
[[Page 85701]]
gracilis), and yellowfin sole (Limanda aspera);
(3) The absence of toxins or other agents of a type or amount
harmful to CIBWs;
(4) Unrestricted passage within or between the critical habitat
areas; and
(5) The absence of in-water noise at levels resulting in the
abandonment of habitat by CIBWs.
The area around the POA, while exempted from the Critical Habitat
designation due to national security issues, does contain the requisite
bathymetric features in the first PCE, as well as the presence of
primary prey species. However, given the industrialized nature of the
POA and the historical use of the site from the early 1900s, the other
physical features are more difficult to confirm. Sediment contamination
was examined during a 2008 U.S. Army Corps of Engineers dredging
project near the Port, and contaminant levels of volatile and semi-
volatile organic compounds, total recoverable petroleum hydrocarbons,
PCBs, pesticides, cadmium, mercury, selenium, silver, arsenic, barium,
chromium, and lead were found to be suitable for in-water discharge
(USACE 2008). Ambient and background noise levels at the POA have been
measured and are addressed quantitatively later in this document;
briefly, noise levels are elevated due to both anthropogenic activities
(i.e., commercial shipping, dredging, and construction) and normal
environmental factors (e.g., high current velocity, ice movement,
seismic activity). While neither contaminants nor noise have been shown
to approach the ``harmful'' and ``habitat abandonment'' thresholds
described in the PCEs, the concentration of both stressors is highest
closer to the POA facilities, within the exemption area, ultimately
degrading the habitat at POA relative to the surrounding areas. In
total, the exempted area surrounding the POA represents approximately
0.35 percent of the designated Critical Habitat Area 1.
Biologically Important Areas. Wild et al. (2023) delineated
portions of Cook Inlet, including near the proposed project area, as a
BIA for the small and resident population of CIBWs based on scoring
methods outlined by Harrison et al. (2023) (see <a href="https://oceannoise.noaa.gov/biologically-important-areas">https://oceannoise.noaa.gov/biologically-important-areas</a> for more information).
The BIA is used year-round by CIBWs for feeding and breeding, and there
are limits on food supply such as salmon runs and seasonal movement of
other fish species (Wild et al., 2023). The boundary of the CIBW BIA is
consistent with NMFS' critical habitat designation and does not include
the aforementioned exclusion areas (e.g., the POA and surrounding
waters) (Wild et al., 2023).
Foraging Ecology. CIBWs feed on a wide variety of prey species,
particularly those that are seasonally abundant. From late spring
through summer, most CIBW stomachs sampled contained salmon, which
corresponded to the timing of fish runs in the area. Anadromous smolt
and adult fish aggregate at river mouths and adjacent intertidal
mudflats (Calkins, 1989). All five Pacific salmon species (i.e.,
Chinook, pink (Oncorhynchus gorbuscha), coho, sockeye, and chum) spawn
in rivers throughout Cook Inlet (Moulton, 1997; Moore et al., 2000).
Overall, Pacific salmon represent the highest percent frequency of
occurrence of prey species in CIBW stomachs. This suggests that their
spring feeding in upper Cook Inlet, principally on fat-rich fish, such
as salmon and eulachon, is important to the energetics of these animals
(NMFS, 2016b).
The nutritional quality of Chinook salmon in particular is
unparalleled, with an energy content four times greater than that of a
Coho salmon. It is suggested the decline of the Chinook salmon
population has left a nutritional void in the diet of the CIBWs that no
other prey species can fill in terms of quality or quantity (Norman et
al., 2020, 2022).
In fall, as anadromous fish runs begin to decline, CIBWs consume
fish species (cod and bottom fish) found in nearshore bays and
estuaries. Stomach samples from CIBWs are not available for winter
(December through March), although dive data from CIBWs tagged with
satellite transmitters suggest that they feed in deeper waters during
winter (Hobbs et al., 2005), possibly on such prey species as flatfish,
cod, sculpin, and pollock.
Fish runs in the Anchorage and Matanuska-Susitna area include
Chinook (May-August), sockeye (June-September), coho (July-September),
pin (July-August), and chum (July-September) salmon, as well as dolly
varden, rainbow and lake trout, northern pike, burbot, grayling, smelt,
and whitefish. In proximity to the POA, anadromous fish runs occur at
Ship Creek, which is heavily used by recreational anglers. On June 26,
2024, the Alaska Department of Fish and Game (ADF&G) issued an
emergency closure of recreational fishing on Ship Creek until July 13,
2024, and limited Chinook catching to catch-and-release for the
remainder of the season due to low returns of Chinook in the creek.
ADF&G anticipates a poor return of this species throughout Knik Arm for
2024, in keeping with a trend of declining Chinook Runs throughout Cook
Inlet since 2008 (ADF&G 2019). The Gulf of Alaska Chinook salmon is
currently under review for listing under the ESA (89 FR 45815, May 24,
2024).
Distribution in Cook Inlet. The CIBW stock remains within Cook
Inlet throughout the year, showing only small seasonal shifts in
distribution (Goetz et al., 2012a; Lammers et al., 2013; Castallotte et
al., 2015; Shelden et al., 2015a, 2018; Lowery et al., 2019). During
spring and summer, CIBWs generally aggregate near the warmer waters of
river mouths where prey availability is high and predator occurrence is
low (Moore et al., 2000; Shelden and Wade, 2019; McGuire et al., 2020).
In particular, CIBW groups are seen in the Susitna River Delta
approximately 36 km (23 mi) to the west of the POA across the mouth of
Knik arm in Upper Cook Inlet, the Beluga River (approximately 55 km (34
mi) west) and along the shore to the Little Susitna River (21 km (13
mi) west), within all of Knik Arm, and along the shores of Chickaloon
Bay to the south of Anchorage, across Turnagain Arm (figure 3). Small
groups were recorded farther south in Kachemak Bay, Redoubt Bay (Big
River), and Trading Bay (McArthur River) prior to 1996 but rarely
thereafter. Since the mid-1990s, most CIBWs (96 to 100 percent)
aggregate in shallow areas near river mouths in upper Cook Inlet, and
they are only occasionally sighted in the central or southern portions
of Cook Inlet during summer (Hobbs et al., 2008). Almost the entire
population can be found in northern Cook Inlet from late spring through
the summer and into the fall (Muto et al., 2020).
[[Page 85702]]
[GRAPHIC] [TIFF OMITTED] TP28OC24.004
Data from tagged whales (14 tags deployed July 2000 through March
2003) show that CIBWs use upper Cook Inlet intensively between summer
and late autumn (Hobbs et al., 2005). CIBWs tagged with satellite
transmitters continue to use Knik Arm, Turnagain Arm, and Chickaloon
Bay as late as October, but some range into lower Cook Inlet to
Chinitna Bay, Tuxedni Bay, and Trading Bay (McArthur River) in fall
(Hobbs et al., 2005, 2012). From September through November, CIBWs move
between Knik Arm, Turnagain Arm, and Chickaloon Bay (Hobbs et al.,
2005; Goetz et al., 2012b). By December, CIBWs are distributed
throughout the upper to mid-inlet. From January into March, they move
as far south as Kalgin Island and slightly beyond in central offshore
waters. CIBWs make occasional excursions into Knik Arm and Turnagain
Arm in February and March in spite of ice cover (Hobbs et al., 2005).
Although tagged CIBWs move widely around Cook Inlet throughout the
year, there is no indication of seasonal migration in and out of Cook
Inlet (Hobbs et al., 2005). Data from NMFS aerial surveys,
opportunistic sighting reports, and corrected satellite-tagged CIBWs
confirm that they are more widely dispersed throughout Cook Inlet
during winter (November-April), with animals found between Kalgin
Island and Point Possession. Generally fewer observations of CIBWs are
reported from the Anchorage and Knik Arm area from November through
April as documented
[[Page 85703]]
in the designation of Critical Habitat (76 FR 20179, April 11, 2011;
Rugh et al., 2000, 2004).
The NMFS Marine Mammal Lab has conducted long-term passive acoustic
monitoring demonstrating seasonal shifts in CIBW concentrations
throughout Cook Inlet. Castellote et al. (2015) conducted long-term
acoustic monitoring at 13 locations throughout Cook Inlet between 2008
and 2015: North Eagle Bay, Eagle River Mouth, South Eagle Bay, Six
Mile, Point MacKenzie, Cairn Point, Fire Island, Little Susitna, Beluga
River, Trading Bay, Kenai River, Tuxedni Bay, and Homer Spit; the
former 6 stations being located within Knik Arm. In general, the
observed seasonal distribution is in accordance with descriptions based
on aerial surveys and satellite telemetry: CIBW detections are higher
in the upper inlet during summer, peaking at Little Susitna, Beluga
River, and Eagle Bay, followed by fewer detections at those locations
during winter. Higher detections in winter at Trading Bay, Kenai River,
and Tuxedni Bay suggest a broader CIBW distribution in the lower inlet
during winter, particularly in Tuxedni Bay in the months of September
through March (Castellote et al., 2015, 2018, 2024; Castellote et al.
2024).
Goetz et al. (2012b) modeled habitat preferences using NMFS' 1994-
2008 June abundance survey data. In large areas, such as the Susitna
Delta (Beluga to Little Susitna Rivers) and Knik Arm, there was a high
probability that CIBWs were in larger groups. CIBW presence and
acoustic foraging behavior also increased closer to rivers with Chinook
salmon runs, such as the Susitna River (e.g., Castellote et al., 2021).
Movement has been correlated with the peak discharge of seven major
rivers emptying into Cook Inlet. Boat-based surveys from 2005 to the
present (McGuire and Stephens, 2017) and results from passive acoustic
monitoring across the entire inlet (Castellote et al., 2015) also
support seasonal patterns observed with other methods. Based on long-
term passive acoustic monitoring, seasonally, foraging behavior was
more prevalent during summer, particularly at upper inlet rivers, than
during winter. Foraging index was highest at Little Susitna, with a
peak in July[hyphen]August and a secondary peak in May, followed by
Beluga River and then Eagle Bay; monthly variation in the foraging
index indicates CIBWs shift their foraging behavior among these three
locations from April through September.
CIBWs are believed to mostly calve in the summer and concurrently
breed between late spring and early summer (NMFS, 2016b), primarily in
upper Cook Inlet. McGuire et al. (2020) documented three suspected
calving events between July and September with no neonates observed
during surveys conducted from April to June. The first neonates
encountered during each field season from 2005 through 2015 were always
seen in the Susitna River Delta in July. Important calving grounds are
thought to be located near the river mouths of upper Cook Inlet--both
potential births documented in July were at the Susitna River Delta;
the third was in Turnagain Arm in September (McGuire et al., 2020). The
photographic identification team's documentation of the dates of the
first neonate of each year indicate that calving begins in mid-late
July/early August, generally coinciding with the observed timing of
annual maximum group size. Probable mating behavior of CIBWs was
observed during all months of the aerial surveys (McGuire et al.,
2020). Young CIBWs are nursed for 2 years and may continue to associate
with their mothers for a considerable time thereafter (Colbeck et al.,
2013). Demographic rates were modeled for this population, indicating
that low survival of non-breeding (i.e., subadult, male, and non-
breeding adult female) CIBWs and general low reproductive rates are
likely contributing to the non-recovery of the population (Himes Boor
et al., 2022).
Presence in Project Area. Knik Arm is one of three areas in upper
Cook Inlet where CIBWs are concentrated during spring, summer, and
early fall. Most CIBWs observed in or near the POA are transiting
between upper Knik Arm and other portions of Cook Inlet, and the POA
itself is not considered high-quality foraging habitat. CIBWs tend to
follow their anadromous prey and travel in and out of Knik Arm with the
tides. The predictive habitat model derived by Goetz et al. (2012a)
indicated that the highest predicted densities of CIBWs are in Knik Arm
near the mouth of the Susitna River and in Chickaloon Bay. The model
suggests that the density of CIBWs ranges from 0 to 1.12 whales per
km\2\ in Cook Inlet but is lower at the mouth of Knik Arm, near the
POA, ranging between approximately 0.013 and 0.062 whales per km\2\.
The distribution presented by Goetz et al. (2012a) is generally
consistent with CIBW distribution documented in upper Cook Inlet
throughout ice-free months (NMFS, 2016b).
Several marine mammal monitoring programs and studies have been
conducted at or near the POA during the last 17 years. These studies
offer some of the best available information on the presence of CIBWs
in the proposed project area. Studies that occurred prior to 2020 are
summarized in Section 4.5.5 of the POA's application. More recent
programs, which most accurately portray current information regarding
CIBW presence in the proposed project area, are summarized here.
PCT Construction Monitoring (2020-2021). A marine mammal monitoring
program was implemented during construction of the PCT in 2020 (Phase
1) and 2021 (Phase 2), as required by the NMFS IHAs (85 FR 19294, April
6, 2020). PCT Phase 1 construction included impact installation of 48-
in (122-cm) attenuated piles; impact installation of 36-in (91-cm) and
48-in (122-cm) unattenuated piles; vibratory installation of 24-in (61-
cm), 36-in (91-cm), and 48-in (122 cm) attenuated and unattenuated
piles; and vibratory installation of an unattenuated 72-in (183-cm)
casing for a confined bubble curtain across 95 days. PCT Phase 2
construction included vibratory installation of 36-in (91-cm)
attenuated piles and impact and vibratory installation of 144-in (366-
cm) attenuated breasting and mooring dolphins across 38 days. Marine
mammal monitoring in 2020 occurred during 128 non-consecutive days with
a total of 1,238.7 hours of monitoring from April 27 to November 24,
2020 (61N Environmental, 2021). Marine mammal monitoring in 2021
occurred during 74 non-consecutive days with a total of 734.9 hours of
monitoring from April 26 to June 24 and September 7 to 29, 2021 (61N
Environmental, 2022a). A total of 1,504 individual CIBWs across 377
groups were sighted during PCT construction monitoring. Sixty-five and
67 percent of CIBW observations occurred on non-pile driving days or
before pile driving occurred on a given day during PCT Phase 1 and PCT
Phase 2 construction, respectively.
The monitoring effort and data collection were conducted before,
during, and after pile driving activities from four locations as
stipulated by the PCT IHAs (85 FR 19294, April 6, 2020): (1) the
Anchorage Public Boat Dock by Ship Creek, (2) the Anchorage Downtown
Viewpoint near Point Woronzof, (3) the PCT construction site, and (4)
the North End (North Extension) at the north end of the POA, near Cairn
Point. Marine mammal sighting data from April to September both before,
during, and after pile driving indicate that CIBWs swam near the POA
and lingered there for periods of time ranging from a few minutes to a
few hours. CIBWs were most often seen traveling at a slow or moderate
pace, either from the north near Cairn Point or from the south or
milling at the
[[Page 85704]]
mouth of Ship Creek. Groups of CIBWs were also observed swimming north
and south in front of the PCT construction and did not appear to
exhibit avoidance behaviors either before, during, or after pile
driving activities (61N Environmental, 2021, 2022a). CIBW sightings in
June were concentrated on the west side of Knik Arm from the Little
Susitna River Delta to Port MacKenzie. From July through September,
CIBWs were most often seen milling and traveling on the east side of
Knik Arm from Point Woronzof to Cairn Point (61N Environmental, 2021,
2022a).
SFD Construction Monitoring and Transitional Dredging (2022). In
2022, a marine mammal monitoring program almost identical to that used
during PCT construction was implemented during construction of the SFD,
as required by the NMFS IHA (86 FR 50057, September 7, 2021). SFD
construction included the vibratory installation of ten 36-in (91-cm)
attenuated plumb piles and two unattenuated battered piles (61N
Environmental, 2022b). Marine mammal monitoring was conducted during 13
non-consecutive days with a total of 108.2 hours of monitoring
observation from May 20 through June 11, 2022 (61N Environmental,
2022b). Forty-one individual CIBWs across 9 groups were sighted (61N
Environmental, 2022b). One group was observed on a day with no pile-
driving, three groups were seen on days before pile driving activities
started, and five groups were seen during vibratory pile driving
activities (61N Environmental, 2022b).
During SFD construction, the position of the Ship Creek monitoring
station was adjusted to allow monitoring of a portion of the shoreline
north of Cairn Point that could not be seen by the station at the
northern end of the POA (61N Environmental, 2022b). Eleven protected
species observers (PSOs) worked from four monitoring stations located
along a 9-km (6-mi) stretch of coastline surrounding the POA. The
monitoring effort and data collection were conducted at the following
four locations: (1) Point Woronzof approximately 6.5 km (4 mi)
southwest of the SFD, (2) the promontory near the boat launch at Ship
Creek, (3) the SFD project site, and (4) the northern end of the POA
(61N Environmental, 2022b).
Ninety groups comprised of 529 CIBWs were also sighted during the
transitional dredging monitoring that occurred from May 3 to 15, 2022
and June 27 to August 24, 2022 (61N Environmental, 2022b). Of the nine
groups of CIBWs sighted during SFD construction, traveling was recorded
as the primary behavior for each group (61N Environmental, 2022b).
CIBWs traveled and milled between the SFD construction area, Ship
Creek, and areas to the south of the POA for more than an hour at a
time, delaying some construction activities.
Harbor Porpoise
Harbor porpoises occur throughout Cook Inlet with passive acoustic
detections being more prevalent in lower Cook Inlet. Although harbor
porpoises have been frequently observed during aerial surveys in Cook
Inlet (Shelden et al., 2014), most sightings are of single animals and
are concentrated at Chinitna and Tuxedni bays on the west side of lower
Cook Inlet (Rugh et al., 2005). The occurrence of larger numbers of
porpoise in the lower Cook Inlet may be driven by greater availability
of preferred prey and possibly less competition with CIBWs as CIBWs
move into upper inlet waters to forage on Pacific salmon during the
summer months (Shelden et al., 2014). There are no known BIAs for
harbor porpoise in Cook Inlet.
An increase in harbor porpoise sightings in upper Cook Inlet has
been observed over recent decades (e.g., 61N Environmental, 2021,
2022a; Shelden et al., 2014). Small numbers of harbor porpoises have
been consistently reported in upper Cook Inlet between April and
October (Prevel-Ramos et al., 2008). The overall increase in the number
of harbor porpoise sightings in upper Cook Inlet is unknown, although
it may be an artifact from increased studies and marine mammal
monitoring programs in upper Cook Inlet. It is also possible that the
apparent contraction in the CIBW's range has opened up previously
occupied CIBW range to harbor porpoises (Shelden et al., 2014).
Harbor porpoises have been observed within Knik Arm during
monitoring efforts from 2005 to 2016. Between April 27 and November 24,
2020, 18 harbor porpoises were observed near the POA during the PCT
Phase 1 construction monitoring (61N Environmental, 2021). Twenty-seven
harbor porpoises were observed near the POA during the PCT Phase 2
construction monitoring conducted between April 26 and September 29,
2021 (61N Environmental, 2022a). During NMFS marine mammal monitoring
conducted in 2021, one harbor porpoise was observed in August and six
harbor porpoises were observed in October (Easley-Appleyard and
Leonard, 2022). During 2022, five harbor porpoises were sighted during
transitional dredging monitoring (61N Environmental, 2022c). No harbor
porpoises were sighted at the POA during the 2022 SFD construction
monitoring that occurred between May and June 2022 (61N Environmental,
2022b).
Steller Sea Lion
Two DPSs of Steller sea lion occur in Alaska: the western DPS and
the eastern DPS. The western DPS includes animals that occur west of
Cape Suckling, Alaska and therefore, includes individuals within the
Project area. The western DPS was listed under the ESA as threatened in
1990 (55 FR 49204, November 26, 1990), and its continued population
decline resulted in a change in listing status to endangered in 1997
(62 FR 24345, May 5, 1997). Since 2000, studies indicate that the
population east of Samalga Pass (i.e., east of the Aleutian Islands)
has increased and is potentially stable (Young et al., 2023).
NMFS designated critical habitat for Steller sea lions on August
27, 1993 (58 FR 45269). The critical habitat designation for the
Western DPS of was determined to include a 37-km (20-nautical mile)
buffer around all major haul-outs and rookeries, and associated
terrestrial, atmospheric, and aquatic zones, plus three large offshore
foraging areas, none of which occurs in the project area. There are no
known BIAs for Steller sea lions in Cook Inlet.
Within Cook Inlet, Steller sea lions primarily inhabit lower Cook
Inlet. However, they occasionally venture to upper Cook Inlet and Knik
Arm and may be attracted to salmon runs in the region. Steller sea
lions have not been documented in upper Cook Inlet during CIBW aerial
surveys conducted annually in June from 1994 through 2012 and in 2014
(Shelden et al., 2013, 2015b, 2017; Shelden and Wade, 2019); however,
there has been an increase in individual Steller sea lion sightings
near the POA in recent years.
Steller sea lions were observed near the POA in 2009, 2016, and
2019 through 2022 (ICRC, 2009; Cornick and Seagars, 2016; POA, 2019;
61N Environmental, 2021, 2022a, 2022b, 2022c). In 2009, there were
three Steller sea lion sightings that were believed to be the same
individual (ICRC, 2009). In 2016, Steller sea lions were observed on 2
separate days. On May 2, 2016, one individual was sighted, while on May
25, 2016, there were five Steller Sea lion sightings within a 50-minute
period, and these sightings occurred in areas relatively close to one
another (Cornick and Seagars, 2016). Given the proximity in time and
space, it is believed these five sightings were of the same individual
sea lion. In 2019, one Steller sea lion was observed in June at the POA
during transitional dredging (POA,
[[Page 85705]]
2019). There were six sightings of individual Steller sea lions near
the POA during PCT Phase 1 construction monitoring (61N Environmental,
2021). At least two of these sightings may have been re-sights on the
same individual. An additional seven unidentified pinnipeds were
observed that could have been Steller sea lions or harbor seals (61N
Environmental, 2021). In 2021, there were a total of eight sightings of
individual Steller sea lions observed near the POA during PCT Phase 2
construction monitoring (61N Environmental, 2022a). During NMFS marine
mammal monitoring, one Steller sea lion was observed in August 2021 in
the middle of the inlet (Easley-Appleyard and Leonard, 2022). In 2022,
there were three Steller sea lion sightings during the transitional
dredging monitoring and three during SFD construction monitoring (61N
Environmental, 2022b, 2022c). All sightings occurred during summer,
when the sea lions were likely attracted to ongoing salmon runs. Sea
lion observations near the POA may be increasing due to more consistent
observation effort or due to increased presence; observations continue
to be occasional.
Harbor Seal
Harbor seals inhabit the coastal and estuarine waters of Cook Inlet
and are observed in both upper and lower Cook Inlet throughout most of
the year (Boveng et al., 2012; Shelden et al., 2013), though there are
no known BIAs for this species in this area. Recent research on
satellite-tagged harbor seals observed several movement patterns within
Cook Inlet (Boveng et al., 2012), including a strong seasonal pattern
of more coastal and restricted spatial use during the spring and summer
(breeding, pupping, molting) and more wide-ranging movements within and
outside of Cook Inlet during the winter months, with some seals ranging
as far as Shumagin Islands. During summer months, movements and
distribution were mostly confined to the west side of Cook Inlet and
Kachemak Bay, and seals captured in lower Cook Inlet generally
exhibited site fidelity by remaining south of the Forelands in lower
Cook Inlet after release (Boveng et al., 2012). In the fall, a portion
of the harbor seals appeared to move out of Cook Inlet and into
Shelikof Strait, northern Kodiak Island, and coastal habitats of the
Alaska Peninsula. The western coast of Cook Inlet had higher usage by
harbor seals than eastern coast habitats, and seals captured in lower
Cook Inlet generally exhibited site fidelity by remaining south of the
Forelands in lower Cook Inlet after release (south of Nikiski; Boveng
et al., 2012).
The presence of harbor seals in upper Cook Inlet is seasonal.
Harbor seals are commonly observed along the Susitna River and other
tributaries within upper Cook Inlet during eulachon and salmon
migrations (NMFS, 2003). The major haulout sites for harbor seals are
in lower Cook Inlet; however, there are a few haulout sites in upper
Cook Inlet, including near the Little and Big Susitna rivers, Beluga
River, Theodore River, and Ivan River (Barbara Mahoney, personal
communication, November 16, 2020; Montgomery et al., 2007). During CIBW
aerial surveys of upper Cook Inlet from 1993 to 2012, harbor seals were
observed 24 to 96 km south-southwest of Anchorage at the Chickaloon,
Little Susitna, Susitna, Ivan, McArthur, and Beluga rivers (Shelden et
al., 2013). Harbor seals have been observed in Knik Arm and in the
vicinity of the POA (Shelden et al., 2013), but they are not known to
haul out within the proposed project area.
Harbor seals were observed during construction monitoring at the
POA from 2005 through 2011 and in 2016, in groups of one to seven
individuals (Prevel-Ramos et al., 2006; Markowitz and McGuire, 2007;
Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010, 2011;
Cornick and Seagars, 2016). Harbor seals were also observed near the
POA during construction monitoring for PCT Phase 1 in 2020 and PCT
Phase 2 in 2021, NMFS marine mammal monitoring in 2021, and
transitional dredging monitoring and SFD construction monitoring in
2022 (61N Environmental, 2021, 2022a, 2022b, 2022c, Easley-Appleyard
and Leonard, 2022). During the 2020 PCT Phase 1 and 2021 PCT Phase 2
construction monitoring, harbor seals were regularly observed in the
vicinity of the POA with frequent observations near the mouth of Ship
Creek, located approximately 1,500 m southeast of the CTR location.
Harbor seals were observed almost daily during 2020 PCT Phase 1
construction, with 54 individuals documented in July, 66 documented in
August, and 44 sighted in September (61N Environmental, 2021). During
the 2021 PCT Phase 2 construction, harbor seals were observed with the
highest numbers of sightings in June (87 individuals) and in September
(124 individuals) (61 N Environmental, 2022a). Over the 13 days of SFD
construction monitoring in May and June 2022, 27 harbor seals were
observed (61N Environmental, 2022b). Seventy-two groups of 75 total
harbor seals (3 groups of 2 individuals) were observed during
transitional dredging monitoring in 2022 (61N Environmental, 2022c).
Sighting rates of harbor seals have been highly variable and may have
increased since 2005. It is unknown whether any potential increase was
due to local population increases or habituation to ongoing
construction activities. It is possible that increased sighting rates
are correlated with more intensive monitoring efforts in 2020 and 2021,
when the POA used 11 PSOs spread among four monitoring stations.
Marine Mammal Hearing
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 are able to 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.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2018, 2024) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained.
On May 3, 2024, NMFS published and solicited public comment on its
draft Updated Technical Guidance (89 FR 36762), which includes updated
hearing ranges and names for the marine mammal hearing groups and is
intended to replace the 2018 Technical Guidance once finalized. The
public comment period ended on June 17th, 2024. Because NMFS may
finalize the Guidance prior to taking a final agency action on this
proposed rulemaking, we considered both the 2018 and 2024 Technical
Guidance in our effects and estimated take analysis below. Marine
mammal hearing groups and their associated hearing ranges from NMFS
(2018) and NMFS (2024) are provided in tables 5 and 6. In the draft
Updated
[[Page 85706]]
Technical Guidance, mid-frequency cetaceans have been re-classified as
high-frequency cetaceans, and high-frequency cetaceans have been
updated to very-high-frequency (VHF) cetaceans. Additionally, the draft
Updated Technical Guidance includes in-air data for phocid (PA) and
otariid (OA) pinnipeds.
Table 5--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
Table 6--Marine Mammal Hearing Groups
[NMFS 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Underwater:
Low-frequency (LF) cetaceans 7 Hz to 36 kHz.
(baleen whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales,
beaked whales, bottlenose
whales).
Very High-frequency (VHF) 200 Hz to 165 kHz.
cetaceans (true porpoises,
Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) 40 Hz to 90 kHz.
(underwater) (true seals).
Otariid pinnipeds (OW) 60 Hz to 68 kHz.
(underwater) (sea lions and fur
seals).
In-air:
Phocid pinnipeds (PA) (true 42 Hz to 52 kHz.
seals).
Otariid pinnipeds (OA) (sea lions 90 Hz to 40 kHz.
and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall
et al. 2019. Additionally, animals are able to detect very loud sounds
above and below that ``generalized'' hearing range
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018, 2024) for a review of available
information.
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
This section 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 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 installation and
removal and impact pile installation. The effects of underwater noise
from the POA's proposed activities have the potential to result in
Level B harassment of marine mammals in the project area and, for some
species as a result of certain activities, Level A harassment.
Background on Sound
This section contains a brief technical background on sound, on the
characteristics of certain sound types and on metrics used relevant to
the specified activity and to a discussion of the potential effects of
the specified activities on marine mammals found later in this
document. For general information on sound and its interaction with the
marine environment, please see: Erbe and Thomas (2022); Au and Hastings
(2008); Richardson et al. (1995); Urick (1983); as well as the
Discovery of Sound in the Sea website at <a href="https://dosits.org/">https://dosits.org/</a>.
Sound is a vibration that travels as an acoustic wave through a
medium such as a gas, liquid or solid. Sound waves alternately compress
and decompress the medium as the wave travels. In water, sound waves
radiate in a manner similar to ripples on the surface of a pond and may
be either directed in a beam (narrow beam or directional sources) or
sound may radiate in all directions (omnidirectional sources), as is
the case for sound produced by the construction activities considered
here. The compressions and decompressions associated with sound waves
are detected as changes in pressure by marine mammals and human-made
sound receptors such as hydrophones.
Sound travels more efficiently in water than almost any other form
of energy, making the use of sound as a primary sensory modality ideal
for inhabitants of the aquatic environment. In seawater, sound travels
at roughly 1,500 meters per second (m/s). In air, sound waves travel
much more slowly at about 340 m/s. However, the speed of sound in water
can vary by a small amount based on characteristics of the
[[Page 85707]]
transmission medium such as temperature and salinity.
The basic characteristics of a sound wave are frequency,
wavelength, velocity, and amplitude. Frequency is the number of
pressure waves that pass by a reference point per unit of time and is
measured in hertz (Hz) or cycles per second. Wavelength is the distance
between two peaks or corresponding points of a sound wave (length of
one cycle). Higher frequency sounds have shorter wavelengths than lower
frequency sounds, and typically attenuate (decrease) more rapidly with
distance. The amplitude of a sound pressure wave is related to the
subjective ``loudness'' of a sound and is typically expressed in dB,
which are a relative unit of measurement that is used to express the
ratio of one value of a power or pressure to another. A sound pressure
level (SPL) in dB is described as the ratio between a measured pressure
and a reference pressure, and is a logarithmic unit that accounts for
large variations in amplitude; therefore, a relatively small change in
dB corresponds to large changes in sound pressure. For example, a 10-dB
increase is a ten-fold increase in acoustic power. A 20-dB increase is
then a 100-fold increase in power and a 30-dB increase is a 1,000-fold
increase in power. However, a ten-fold increase in acoustic power does
not mean that the sound is perceived as being 10 times louder due to
the anatomy of mammalian ears. A 10-dB increase in sound is perceived
as a doubling of loudness to the human ear, and marine mammal studies
of loudness perception are ongoing (Houser et al. 2017).
The dB is a relative unit comparing two pressures; therefore, a
reference pressure must always be indicated. For underwater sound, this
is 1 microPascal ([mu]Pa). For in-air sound, the reference pressure is
20 microPascal ([mu]Pa). The amplitude of a sound can be presented in
various ways; however, NMFS typically considers three metrics: sound
exposure level (SEL), root-mean-square (RMS) SPL, and peak SPL (defined
below). The source level represents the SPL referenced at a standard
distance from the source, typically 1 m (Richardson et al., 1995;
American National Standards Institute (ANSI, 2013), while the received
level is the SPL at the receiver's position. For pile driving
activities, the SPL is typically referenced at 10 m.
SEL (represented as dB referenced to 1 micropascal squared second
(re 1 [mu]Pa\2\-s)) represents the total energy in a stated frequency
band over a stated time interval or event, and considers both intensity
and duration of exposure. The per-pulse SEL (e.g., single strike or
single shot SEL) is calculated over the time window containing the
entire pulse (i.e., 100 percent of the acoustic energy). SEL can also
be a cumulative metric; it can be accumulated over a single pulse (for
pile driving this is the same as single-strike SEL, above;
SEL<INF>ss</INF>), or calculated over periods containing multiple
pulses (SEL<INF>cum</INF>). Cumulative SEL (SEL<INF>cum</INF>)
represents the total energy accumulated by a receiver over a defined
time window or during an event. The SEL metric is useful because it
allows sound exposures of different durations to be related to one
another in terms of total acoustic energy. The duration of a sound
event and the number of pulses, however, should be specified as there
is no accepted standard duration over which the summation of energy is
measured.
RMS SPL is equal to 10 times the logarithm (base 10) of the ratio
of the mean-square sound pressure to the specified reference value, and
given in units of dB (International Organization for Standardization
(ISO), 2017). RMS is calculated by squaring all of the sound
amplitudes, averaging the squares, and then taking the square root of
the average (Urick, 1983). RMS accounts for both positive and negative
values; squaring the pressures makes all values positive so that they
may be accounted for in the summation of pressure levels (Hastings and
Popper, 2005). This measurement is often used in the context of
discussing behavioral effects, in part because behavioral effects,
which often result from auditory cues, may be better expressed through
averaged units than by peak SPL. For impulsive sounds, RMS is
calculated by the portion of the waveform containing 90 percent of the
sound energy from the impulsive event (Madsen, 2005).
Peak SPL (also referred to as zero-to-peak sound pressure or 0-pk)
is the maximum instantaneous sound pressure measurable in the water,
which can arise from a positive or negative sound pressure, during a
specified time, for a specific frequency range at a specified distance
from the source, and is represented in the same units as the RMS sound
pressure (ISO, 2017). Along with SEL, this metric is used in evaluating
the potential for permanent threshold shift (PTS) and temporary
threshold shift (TTS) associated with impulsive sound sources.
Sounds are also characterized by their temporal components.
Continuous sounds are those whose sound pressure level remains above
that of the ambient or background sound with negligibly small
fluctuations in level (ANSI, 2005) while intermittent sounds are
defined as sounds with interrupted levels of low or no sound (National
Institute for Occupational Safety and Health (NIOSH), 1998). A key
distinction between continuous and intermittent sound sources is that
intermittent sounds have a more regular (predictable) pattern of bursts
of sounds and silent periods (i.e., duty cycle), which continuous
sounds do not.
Sounds may be either impulsive or non-impulsive (defined below).
The distinction between these two sound types is important because they
have differing potential to cause physical effects, particularly with
regard to noise-induced hearing loss (e.g., Ward, 1997 in Southall et
al., 2007). Please see NMFS (2018) and Southall et al. (2007, 2019) for
an in-depth discussion of these concepts.
Impulsive sound sources (e.g., explosions, gunshots, sonic booms,
seismic airgun shots, impact pile driving) produce signals that are
brief (typically considered to be less than 1 second), broadband,
atonal transients (ANSI, 1986, 2005; NIOSH, 1998) and occur either as
isolated events or repeated in some succession. Impulsive sounds are
all characterized by a relatively rapid rise from ambient pressure to a
maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features. Impulsive
sounds are intermittent in nature. The duration of such sounds, as
received at a distance, can be greatly extended in a highly reverberant
environment.
Non-impulsive sounds can be tonal, narrowband, or broadband, brief
or prolonged, and may be either continuous or non-continuous (i.e.,
intermittent) (ANSI, 1995; NIOSH, 1998). Some of these non-impulsive
sounds can be transient signals of short duration but without the
essential properties of impulses (e.g., rapid rise time). Examples of
non-impulsive sounds include those produced by vessels, aircraft,
machinery operations such as drilling or dredging, vibratory pile
driving, and active sonar systems.
Even in the absence of sound from the specified activity, the
underwater environment is characterized by sounds from both natural and
anthropogenic sound sources. Ambient sound is defined as a composite of
naturally-occurring (i.e., non-anthropogenic) sound from many sources
both near and far (ANSI, 1995). Background sound is similar but
includes all sounds, including anthropogenic sounds minus
[[Page 85708]]
the sound produced by the proposed activities (NMFS, 2012, 2016a). The
sound level of a region is defined by the total acoustical energy being
generated by known and unknown sources. These sources may include
physical (e.g., wind and waves, earthquakes, ice, atmospheric sound),
biological (e.g., sounds produced by marine mammals, fish, and
invertebrates), and anthropogenic (e.g., vessels, dredging,
construction) sound. A number of sources contribute to background and
ambient sound, including wind and waves, which are a main source of
naturally occurring ambient sound for frequencies between 200 Hz and 50
kilohertz (kHz) (Mitson, 1995). In general, background and ambient
sound levels tend to increase with increasing wind speed and wave
height. Precipitation can become an important component of total sound
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times. Marine mammals can contribute significantly to background and
ambient sound levels, as can some fish and snapping shrimp. The
frequency band for biological contributions is from approximately 12 Hz
to over 100 kHz. Sources of background sound related to human activity
include transportation (surface vessels), dredging and construction,
oil and gas drilling and production, geophysical surveys, sonar, and
explosions. Vessel noise typically dominates the total background sound
for frequencies between 20 and 300 Hz. In general, the frequencies of
many anthropogenic sounds, particularly those produced by construction
activities, are below 1 kHz (Richardson et al., 1995). When sounds at
frequencies greater than 1 kHz are produced, they generally attenuate
relatively rapidly (Richardson et al., 1995), particularly above 20 kHz
due to propagation losses and absorption (Urick, 1983).
Transmission loss (TL) defines the degree to which underwater sound
has spread in space and lost energy after having moved through the
environment and reached a receiver. It is defined by the ISO as the
reduction in a specified level between two specified points that are
within an underwater acoustic field (ISO, 2017). Careful consideration
of transmission loss and appropriate propagation modeling is a crucial
step in determining the impacts of underwater sound, as it helps to
define the ranges (isopleths) to which impacts are expected and depends
significantly on local environmental parameters such as seabed type,
water depth (bathymetry), and the local speed of sound. Geometric
spreading laws are powerful tools which provide a simple means of
estimating TL, based on the shape of the sound wave front in the water
column. For a sound source that is equally loud in all directions and
in deep water, the sound field takes the form of a sphere, as the sound
extends in every direction uniformly. In this case, the intensity of
the sound is spread across the surface of the sphere, and thus we can
relate intensity loss to the square of the range (as area = 4*pi*r\2\).
This can be expressed logarithmically, where TL =
20*Log<INF>10</INF>(range). This situation is known as spherical
spreading. In shallow water, the sea surface and seafloor will bound
the shape of the sound wave, leading to a more cylindrical shape, as
the top and bottom of the sphere is truncated by the largely reflective
boundaries. This situation is termed cylindrical spreading, and is
given by TL = 10*Log<INF>10</INF>(range) (Urick, 1983). An intermediate
scenario may be defined by the equation TL =
15*Log<INF>10</INF>(range), and is referred to as practical spreading.
Though these geometric spreading scenarios do not capture many often
important details (scattering, absorption, etc.), they offer a
reasonable and simple approximation of how sound decreases in intensity
as it is transmitted. In the absence of measured data indicating the
level of transmission loss at a given site for a specific activity,
NMFS recommends practical spreading (i.e., TL =
15*Log<INF>10</INF>(range)) to model acoustic propagation for
construction activities in most nearshore environments.
The sum of the various natural and anthropogenic sound sources at
any given location and time depends not only on the source levels, but
also on the propagation of sound through the environment. Sound
propagation is dependent on the spatially and temporally varying
properties of the water column and sea floor, and is frequency-
dependent. As a result of the dependence on a large number of varying
factors, background and ambient sound levels can be expected to vary
widely over both coarse and fine spatial and temporal scales. Sound
levels at a given frequency and location can vary by 10 to 20 dB from
day to day (Richardson et al., 1995). The result is that, depending on
the source type and its intensity, sound from the specified activity
may be a negligible addition to the local environment or could form a
distinctive signal that may affect marine mammals.
Background underwater noise levels in the CTR Project area are both
variable and relatively high, primarily because of extreme tidal
activity, elevated sediment loads in the water column, periodic high
winds, the seasonal presence of ice, and anthropogenic activities.
Sources of anthropogenic noise in the CTR Project area consist of
dredging operations, boats, ships, oil and gas operations, construction
noise, and aircraft overflights from JBER and Ted Stevens International
Airport, all of which contribute to high underwater noise levels in
upper Cook Inlet (e.g., Blackwell and Greene, 2002; (Knik Arm Bridge
and Toll Authority (KABATA), 2011; Castellote et al., 2018).
Background sound levels were measured at the POA during the PAMP
2016 Test Pile Program (TPP) in the absence of pile driving at two
locations during a 3[hyphen]day break in pile installation. Median
background noise levels, measured at a location just offshore of the
POA SFD and at a second location about 1 km offshore, were 117 and
122.2 dB RMS, respectively (Austin et al., 2016). NMFS considers the
median sound levels to be most appropriate when considering background
noise levels for purposes of evaluating the potential impacts of the
proposed project on marine mammals (NMFS, 2012). By using the median
value, which is the 50th percentile of the measurements, for background
noise levels, one will be able to eliminate the few transient loud
identifiable events that do not represent the true ambient condition of
the area. This is relevant because during 2 of the 4 days (50 percent)
when background measurement data were being collected, the USACE was
dredging Terminal 3 (located just north of the Ambient-Offshore
hydrophone) for 24 hours per day with two 1-hour breaks for crew
change. On the last 2 days of data collection, no dredging occurred.
Therefore, the median provides a better representation of background
noise levels when the CTR project would be occurring. During the
measurements, some typical sound signals were noted, such as noise from
current flow and the passage of vessels.
With regard to spatial considerations of the measurements, the
offshore location is most applicable to assessing background sound
during the CTR project (NMFS, 2012). The median background noise level
measured at the offshore hydrophone was 122.2 dB RMS. The measurement
location closer to the POA was quieter, with a median of 117 dB;
however, that hydrophone was placed very close to a dock. During PCT
acoustic monitoring, noise levels in Knik Arm absent pile driving were
also collected (Illingworth & Rodkin (I&R), 2021a, 2022b)); however,
the PCT IHAs did not require background noise
[[Page 85709]]
measurements to be collected in adherence with NMFS (2012)
methodological recommendations. Despite this, the noise levels measured
during the PCT project were not significantly different from 122.2 dB
(I&R, 2021a, 2022b). If additional background data are collected in the
future in this region, NMFS may re-evaluate the data to appropriately
characterize background sound levels in Knik Arm.
Description of Sound Sources for the Specified Activities
In-water construction activities associated with the project that
have the potential to incidentally take marine mammals through exposure
to sound would include impact pile installation and vibratory pile
installation and removal. Impact hammers typically operate by
repeatedly dropping and/or pushing a heavy piston onto a pile to drive
the pile into the substrate. Sound generated by impact hammers is
impulsive, characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
typically produce less sound (i.e., lower levels) than impact hammers.
Peak 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; 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).
The likely or possible impacts of the POA's proposed activities on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, given there are no
known pinniped haul-out sites in the vicinity of the CTR project site,
visual and other non-acoustic stressors would be limited, and any
impacts to marine mammals are expected to primarily be acoustic in
nature.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving is the primary means by which marine
mammals may be harassed from the POA's specified activity. 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 pile driving 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). Exposure to anthropogenic noise
can also lead to non-observable physiological responses, such as an
increase in stress hormones. Additional noise in a marine mammal's
habitat can mask acoustic cues used by marine mammals to carry out
daily functions, such as communication and predator and prey detection.
The effects of pile driving noise on marine mammals are dependent on
several factors, including, but not limited to, sound type (e.g.,
impulsive vs. non-impulsive), the species, age and sex class (e.g.,
adult male vs. mom with calf), duration of exposure, the distance
between the pile and the animal, received levels, behavior at time of
exposure, and previous history with exposure (Wartzok et al., 2004;
Southall et al., 2007). Here, we discuss physical auditory effects
(threshold shifts) followed by behavioral effects and potential impacts
on habitat.
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). The amount of
threshold shift is customarily expressed in dB. A 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 and Permanent Threshold Shift (PTS). NMFS defines
auditory injury as ``damage to the inner ear that can result in
destruction of tissue . . . which may or may not result in PTS'' (NMFS,
2024). NMFS defines PTS 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 incurred some
level of hearing loss at the relevant frequencies; typically, animals
with PTS 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 PTS onset (see Ward
et al., 1958, 1959, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et
al., 1996; Henderson et al., 2008). PTS levels for marine mammals are
estimates, as with the exception of a single study unintentionally
inducing PTS in a harbor seal (Kastak et al., 2008), there are no
empirical data measuring PTS in marine mammals largely due to the fact
that, for various ethical reasons, experiments involving anthropogenic
noise exposure at levels inducing PTS are not typically pursued or
authorized (NMFS, 2018).
Temporary Threshold Shift (TTS). 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, 2018). 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 SEL<INF>cum</INF> in an accelerating fashion: at low exposures
with lower SEL<INF>cum</INF>, the amount of TTS is typically small and
the growth curves have shallow slopes. At exposures with higher
SEL<INF>cum</INF>, the growth curves become steeper and approach linear
relationships with the noise 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 serious (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
[[Page 85710]]
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 serious 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.
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 of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise,
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et
al., 2019). For pinnipeds in water, measurements of TTS are limited to
harbor seals, elephant seals (Mirounga angustirostris), bearded seals
(Erignathus barbatus) and California sea lions (Zalophus californianus)
(Kastak et al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021,
2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020). TTS was not
observed in spotted (Phoca largha) and ringed (Pusa hispida) seals
exposed to single airgun impulse sounds at levels matching previous
predictions of TTS onset (Reichmuth et al., 2016). These studies
examine hearing thresholds measured in marine mammals before and after
exposure to intense or long-duration sound exposures. The difference
between the pre-exposure and post-exposure thresholds can be used to
determine the amount of threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, 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 (i.e., 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, cumulative
SEL 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, 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, 2018).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans. However,
such relationships are assumed to be similar to those in humans and
other terrestrial mammals. PTS typically occurs at exposure levels at
least several dB above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS 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 PTS 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
PTS 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 PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Behavioral Harassment. 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); avoidance of areas where sound sources are located.
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, Erbe et al., 2019). 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
[[Page 85711]]
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.
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
responses, often in the form of avoidance, at a lower level of
exposure.
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 showed
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.
However, 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.
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. However, acoustic and movement bio-logging tools have been
used in some cases, to infer responses of feeding to anthropogenic
noise. For example, Blair et al. (2016) 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.
In response to playbacks of vibratory pile driving sounds, captive
bottlenose dolphins showed changes in target detection and number of
clicks used for a trained echolocation task (Branstetter et al. 2018).
Similarly, harbor porpoises trained to collect fish during playback of
impact pile driving sounds also showed potential changes in behavior
and task success, though individual differences were prevalent
(Kastelein et al. 2019d). 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
relationships among prey availability, foraging effort and success, and
the life history stage(s) of the animal.
Variations in respiration naturally vary 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 rate increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike:
127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
Avoidance is the displacement of an individual from an area or
migration path as a result 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). In response to construction noise from offshore wind farms,
harbor porpoises and harbor seals have demonstrated avoidance on the
scale of hours to weeks (Brandt et al., 2018; Russell et al., 2016).
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
[[Page 85712]]
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.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects.
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 1 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.
Behavioral Reactions Observed at the POA. Specific to recent
construction at the POA, behavioral reactions to pile driving have not
been reported in non-CIBW species. During POA's PCT construction, 81
harbor seals were observed within estimated Level B harassment zones
associated with vibratory and impact installation and removal of 36-in
(61-cm) and 144-in (366-cm) piles, and 5 harbor seals were observed
within estimated Level A harassment zones during the installation of
144-in (366-cm) piles. No observable behavioral reactions were observed
in any of these seals (61N Environmental, 2021, 2022a). One harbor
porpoise was observed within the estimated Level B harassment zone
during vibratory driving of a 36-in (61-cm) pile in May 2021. The
animal was traveling at a moderate pace. No observable reactions to
pile driving were noted by the PSOs. Another harbor porpoise near the
border of (and may have been within) the estimated Level B harassment
zone during the impact installation of 36-in (61-cm) piles in June
2021, but PSOs did not record any behavioral responses of this
individual to the pile driving activities. Similarly 13 harbor seals
observed within estimated Level B harassment zones associated with pile
driving 36-in (61-cm) piles during POA's SFD construction did not
exhibit observable behavioral reactions (61N Environmental, 2022b).
Specific to CIBWs, several years of marine mammal monitoring data
demonstrate behavioral responses to pile driving at the POA. Previous
pile driving activities at the POA include the installation and removal
of sheet piles, the vibratory and impact installation of 24-in (61-cm),
36-in (91-cm), 48-in (122-cm), and 144-in (366-cm) pipe piles, and the
vibratory installation of 72-in (182-cm) air bubble casings.
Kendall and Cornick (2015) provide a comprehensive overview of 4
years of scientific marine mammal monitoring conducted before (2005-
2006) and during the POA's MTRP (2008-2009). These were observations
made by biologists at Alaska Pacific University, funded by the POA and
other groups but independent of the POA's required monitoring for pile
driving activities (i.e., not construction based PSOs). The authors
investigated CIBW behavior before and during pile driving activity at
the POA. Sighting rates, mean sighting duration, behavior, mean group
size, group composition, and group formation were compared between the
two periods. A total of about 2,329 hours of sampling effort was
completed across 349 days from 2005 to 2009. Overall, 687 whales in 177
groups were documented during the 69 days that whales were sighted. A
total of 353 and 1,663 hours of pile driving took place in 2008 and
2009, respectively. There was no relationship between monthly CIBW
sighting rates and monthly pile driving rates (r = 0.19, p = 0.37).
Sighting rates before (n = 12; 0.06 <plus-minus> 0.01) and during (n =
13; 0.01 <plus-minus> 0.03) pile driving were not significantly
different. However, sighting duration of CIBWs decreased significantly
during pile driving (39 <plus-minus> 6 min before and 18 <plus-minus> 3
min during). There were also significant differences in behavior before
versus during pile driving. CIBWs primarily traveled through the study
area both before and during pile driving; however, traveling increased
relative to other behaviors during pile driving. Documentation of
milling was observed on 21 occasions during pile driving. Mean group
size decreased during pile driving; however, this difference was not
statistically significant. In addition, group composition was
significantly different before and during pile driving, with more white
(i.e., likely older) animals being present during pile driving (Kendall
and Cornick, 2015). CIBWs were primarily observed densely packed before
and during pile driving; however, the number of densely packed groups
increased by approximately 67 percent during pile driving. There were
also significant increases in the number of dispersed groups
(approximately 81 percent) and lone white whales (approximately 60
percent) present during pile driving than before pile driving (Kendall
and Cornick, 2015).
During PCT and SFD construction monitoring, behaviors of CIBWs
groups were compared by month and by construction activity (61N
Environmental, 2021, 2022a, 2022b). Little variability was evident in
the behaviors recorded from month to month or among sightings that
coincided with in-water pile installation and removal and those that
did not (61N Environmental, 2021, 2022a). Definitive behavioral
reactions to in-water pile
[[Page 85713]]
driving or avoidance behaviors were not documented; however, potential
reactions (where a group reversed its trajectory shortly after the
start of in-water pile driving occurred; a group reversed its
trajectory as it got closer to the sound source during active in-water
pile driving; or upon an initial sighting, a group was already moving
away from in-water pile driving, raising the possibility that it had
been moving towards, but was only sighted after they turned away) and
instances where CIBWs moved toward active in-water pile driving were
recorded. During these instances, impact driving appeared to cause
potential behavioral reactions more readily than vibratory hammering
(61N Environmental, 2021, 2022a, 2022b). One minor difference
documented during PCT construction was a slightly higher incidence of
milling behavior and diving during the periods of no pile driving and
slightly higher rates of traveling behavior during periods when
potential CIBW behavioral reactions to pile driving, as described
above, were recorded (61N Environmental, 2021, 2022a). Note, narratives
of each CIBW reaction can be found in the appendices of the POA's final
monitoring reports (61N Environmental, 2021, 2022a, 2022b).
Acoustically, Saxon-Kendall et al. (2013) recorded echolocation
clicks (which can be indicative of feeding behavior) during the MTR
Project at the POA both while pile driving was occurring and when it
was not. This indicates that while feeding is not a predominant
behavior that PSOs visually observed in CIBWs sighted near the POA (61N
Environmental, 2021, 2022a, 2022b, 2022c; Easley-Appleyard and Leonard,
2022) CIBWs can and still exhibit feeding behaviors during pile driving
activities. In addition, Castellote et al. (2020) found low
echolocation detection rates in lower Knik Arm (i.e., Six Mile, Port
MacKenzie, and Cairn Point) and suggested that CIBWs moved through that
area relatively quickly when entering or exiting the Arm. No whistles
or noisy vocalizations were recorded during the MTRP construction
activities; however, it is possible that persistent noise associated
with construction activity at the MTR project masked beluga
vocalizations and or that CIBWs did not use these communicative signals
when they were near the MTR Project (Saxon-Kendall et al., 2013).
Recently, McHuron et al. (2023) developed a model to predict
general patterns related to the movement and foraging decisions of
pregnant CIBWs in Cook Inlet. They found that the effects of
disturbance from human activities, such as pile driving activities
occurring at the POA assuming no mitigation measures, are inextricably
linked with prey availability. If prey are abundant during the summer
and early fall and prey during winter is above some critical threshold,
pregnant CIBWs can likely cope with intermittent disruptions, such as
those produced by pile driving at the POA (McHuron et al., 2023).
However, they stress that more information needs to be acquired
regarding CIBW prey and CIBW body condition, specifically in their
critical habitat, to better understand possible behavioral responses to
disturbance.
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). 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. 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. 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.
Norman (2011) reviewed environmental and anthropogenic stressors
for CIBWs. Lyamin et al. (2011) determined that the heart rate of a
beluga whale increases in response to noise, depending on the frequency
and intensity. Acceleration of heart rate in the beluga whale is the
first component of the ``acoustic startle response.'' Romano et al.
(2004) demonstrated that captive beluga whales exposed to high-level
impulsive sounds (i.e., seismic airgun and/or single pure tones up to
201 dB RMS) resembling sonar pings showed increased stress hormone
levels of norepinephrine, epinephrine, and dopamine when TTS was
reached. Thomas et al. (1990) exposed beluga whales to playbacks of an
oil-drilling platform in operation (``Sedco 708,'' 40 Hz-20 kHz; source
level 153 dB). Ambient SPL at ambient conditions in the pool before
playbacks was 106 dB and 134 to 137 dB RMS during playbacks at the
monitoring hydrophone across the pool. All cell and platelet counts and
21 different blood chemicals, including epinephrine and norepinephrine,
were within normal
[[Page 85714]]
limits throughout baseline and playback periods, and stress response
hormone levels did not increase immediately after playbacks. The
difference between the Romano et al. (2004) and Thomas et al. (1990)
studies could be the differences in the type of sound (seismic airgun
and/or tone versus oil drilling), the intensity and duration of the
sound, the individual's response, and the surrounding circumstances of
the individual's environment. The construction sounds in the Thomas et
al. (1990) study would be more similar to those of pile installation
than those in the study investigating stress response to water guns and
pure tones. Therefore, no more than short-term, low-level hormonal
stress responses, if any, of beluga whales or other marine mammals are
expected as a result of exposure to in-water pile installation and
removal during the CTR project.
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 environment
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).
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 response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). Fin whales have also been documented
lowering the bandwidth, peak frequency, and center frequency of their
vocalizations under increased levels of background noise from large
vessels (Castellote et al. 2012). Other alterations to communication
signals have also been observed. For example, gray whales, in response
to playback experiments exposing them to vessel noise, have been
observed increasing their vocalization rate and producing louder
signals at times of increased outboard engine noise (Dahlheim and
Castellote, 2016). Alternatively, animals may cease sound production
during production of aversive signals (Bowles et al., 1994).
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 (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).
Marine mammals at or near the proposed CTR project site may be
exposed to anthropogenic noise, which may be a source of masking.
Vocalization changes may result from a need to compete with an increase
in background noise and include increasing the source level, modifying
the frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks and communication
signals, reduce their overall calling rates, and or increase the
emission of certain call signals to prevent masking by anthropogenic
noise (Lessage et al., 1999; Tyack, 2000; Eickmeier and Vallarta,
2022).
Masking occurs in the frequency band or bands that animals utilize
and is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. Energy
distribution of pile driving covers a broad frequency spectrum, and
sound from pile driving would be within the audible range of pinnipeds
and cetaceans present in the proposed action area. While some
construction during the POA's 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.
Airborne Acoustic Effects. Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with construction
activities that have
[[Page 85715]]
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. Although pinnipeds are known to haul-out regularly
on man-made objects, we believe that incidents of take resulting solely
from airborne sound are unlikely given there are no known pinniped
haulout or pupping sites within the vicinity of the proposed project
area; the nearest known pinniped haulout is located a minimum of 24 km
south-southwest of Anchorage for harbor seals. 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, 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 to exhibit changes in their normal behavior, such as
reduction in vocalizations or cause them to temporarily abandon the
area and 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
The proposed project would occur mostly within the same footprint
as existing marine infrastructure; the new T1 and T2 would extend
approximately 140 ft (47-m) seaward of the existing terminals. The
nearshore and intertidal habitat where the proposed project will occur
is an area of relatively high marine vessel traffic. Temporary,
intermittent habitat alteration may result from increased noise levels
during the proposed construction activities. Noise from impact and
vibratory pile driving may extend across Knik Arm, and affect areas
outside of the area around POA excluded from designated CIBW Critical
Habitat. However, increased noise levels will only be present during
construction activities and will cease when pile driving ends. Pile
driving is not expected on all days during the construction season
(April-November) and is not expected at all during the months of
December-March. Noise exposure is, therefore, expected to be temporary
and intermittent with long periods of typical background noise levels
on a daily and seasonal scale. Effects to CIBW critical habitat are,
therefore, considered to be non-significant. Effects on prey species
will be limited in time and space. The long-term impact on marine
mammal habitat associated with CTR would be a small permanent decrease
in low-quality potential habitat because of the expanded footprint of
the new cargo terminals T1 and T2. Installation and removal of in-water
piles would be temporary and intermittent, and the increased footprint
of the facilities would destroy only a small amount of low-quality
habitat, which currently experiences high levels of anthropogenic
activity.
Water quality--Temporary and localized reduction in water quality
would occur as a result 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 would disturb bottom sediments and may cause a temporary increase
in suspended sediment in the project area. During pile removal,
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. Since the currents are so strong in the
area, 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. Thus, 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 Knik Arm, and does not include any
areas of particular importance.
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, 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 high amplitude and/or
intermittent at low frequencies. 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 impulsive
sounds might affect the distribution and behavior of some fishes,
potentially impacting foraging opportunities or increasing energetic
costs (e.g., Fewtrell
[[Page 85716]]
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., Pe[ntilde]a 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.
During the POA's MTRP, the effects of impact and vibratory
installation of 30-in (76-cm) steel sheet piles at the POA on 133 caged
juvenile coho salmon in Knik Arm were studied (Hart Crowser
Incorporated et al., 2009; Houghton et al., 2010). Acute or delayed
mortalities or behavioral abnormalities were not observed in any of the
coho salmon. Furthermore, results indicated that the pile driving had
no adverse effect on feeding ability or the ability of the fish to
respond normally to threatening stimuli (Hart Crowser Incorporated et
al., 2009; Houghton et al., 2010).
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, 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).
Essential Fish Habitat (EFH) has been designated in the estuarine
and marine waters in the vicinity of the proposed project area for all
five species of salmon (i.e., chum salmon, pink salmon, coho salmon,
sockeye salmon, and Chinook salmon; North Pacific Fishery Management
Council (NPFMC), 2020, 2021), which are common prey of marine mammals,
as well as for o
[…truncated; see source link]Indexed from Federal Register on October 28, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.