[Federal Register Volume 82, Number 12 (Thursday, January 19, 2017)]
[Notices]
[Pages 6627-6634]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-01271]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

[FWS-R8-ES-2016-N187; FXES111608M0000]


Marine Mammals; Incidental Take During Specified Activities; 
Proposed Incidental Harassment Authorization

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of receipt of application and proposed incidental 
harassment authorization; request for comments.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), have 
received an application from the California Department of Fish and 
Wildlife, Central Region, for authorization to take small numbers of 
marine mammals by harassment incidental to construction activities as 
part of a tidal marsh restoration project within the Minhoto-Hester 
Marsh in Elkhorn Slough, Monterey County, California. In accordance 
with provisions of the Marine Mammal Protection Act of 1972,

[[Page 6628]]

as amended, we request comments on our proposed authorization for the 
applicant to take incidentally, by harassment, small numbers of 
southern sea otters (Enhydra lutris nereis) over the course of 
approximately 11 months beginning between January 2017 and June 2017. 
We anticipate no take by injury or death and include none in this 
proposed authorization, which would be for take by harassment only.

DATES: Comments and information must be received by February 21, 2017.

ADDRESSES: Comment submission: You may submit comments by any one of 
the following methods:
    1. U.S. mail or hand-delivery: Steve Henry, Field Supervisor, 
Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, 
CA 93003.
    2. Fax: 805-644-3958, attention to Steve Henry, Field Supervisor.
    3. Electronic mail (email): [email protected]. Please 
include your name and U.S. mail address in your message.
    Document availability: Electronic copies of the incidental 
harassment authorization request, the Marine Mammal Monitoring Plan, 
and other supporting materials, such as the list of references used in 
this notice, may be obtained by writing to the address specified above, 
telephoning the contact listed in FOR FURTHER INFORMATION CONTACT, or 
visiting the Internet at http://www.fws.gov/ventura/endangered/species/info/sso.html. Documents cited in this notice may also be viewed, by 
appointment, during regular business hours, at the aforementioned U.S. 
mail address.

FOR FURTHER INFORMATION CONTACT: Lilian Carswell, Southern Sea Otter 
Recovery & Marine Conservation Coordinator, (805) 612-2793, or by email 
at [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the Marine Mammal Protection Act 
of 1972, as amended, (MMPA; 16 U.S.C. 1371 (a)(5)(A) and (D)), 
authorize the Secretary of the Interior 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, provided 
that we make certain findings and either issue regulations or, if the 
taking is limited to harassment, provide a notice of a proposed 
authorization to the public for review and comment.
    We may grant authorization to incidentally take marine mammals if 
we find 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 subsistence uses. As part 
of the authorization process, we prescribe permissible methods of 
taking and other means of effecting the least practicable impact on the 
species or stock and its habitat, and requirements pertaining to the 
monitoring and reporting of such takings.
    The term ``take,'' as defined by the MMPA, means to harass, hunt, 
capture, or kill, or to attempt to harass, hunt, capture, or kill, any 
marine mammal. Harassment, as defined by the MMPA, means ``any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild [the MMPA calls this 
Level A harassment], or (ii) has the potential to disturb a marine 
mammal or marine mammal stock in the wild by causing disruption of 
behavioral patterns, including, but not limited to, migration, 
breathing, nursing, breeding, feeding, or sheltering [the MMPA calls 
this Level B harassment].''
    The terms ``negligible impact,'' ``small numbers,'' and 
``unmitigable adverse impact'' are defined in title 50 of the Code of 
Federal Regulations at 50 CFR 18.27, the Service's regulations 
governing take of small numbers of marine mammals incidental to 
specified activities. ``Negligible impact'' is defined as ``an impact 
resulting from the specified activity that cannot be reasonably 
expected to, and is not reasonably likely to, adversely affect the 
species or stock through effects on annual rates of recruitment or 
survival.'' The term ``small numbers'' is also defined in the 
regulations as ``a portion of a marine mammal species or stock whose 
taking would have a negligible impact on that species or stock.'' 
However, we do not rely on that definition here, as it conflates the 
terms ``small numbers'' and ``negligible impact,'' which we recognize 
as two separate and distinct requirements. Instead, in our small 
numbers determination, we evaluate whether the number of marine mammals 
likely to be taken is small relative to the size of the overall 
population. ``Unmitigable adverse impact'' is defined as ``an impact 
resulting from the specified activity (1) that is likely to reduce the 
availability of the species to a level insufficient for a harvest to 
meet subsistence needs by (i) causing the marine mammals to abandon or 
avoid hunting areas, (ii) directly displacing subsistence users, or 
(iii) placing physical barriers between the marine mammals and the 
subsistence hunters; and (2) that cannot be sufficiently mitigated by 
other measures to increase the availability of marine mammals to allow 
subsistence needs to be met.'' The subsistence provision applies to 
northern sea otters (Enhydra lutris kenyoni) in Alaska but not to 
southern sea otters.

Summary of Request

    On May 23, 2016, we received an application from the California 
Department of Fish and Wildlife, Central Region (CDFW), for 
authorization to take southern sea otters incidental to construction 
activities associated with a 47-acre tidal marsh restoration project 
within the Minhoto-Hester Marsh in Elkhorn Slough, Monterey County, 
California. The project would reduce tidal prism in Elkhorn Slough, 
reducing the potential for ongoing tidal scour and associated marsh 
loss. It would also improve marsh sustainability with sea level rise, 
as the restored marsh would be higher in the tidal frame and further 
from the drowning threshold, and marsh vegetation in the restored areas 
would accrete organic material that would help the restored marsh plain 
rise with sea level. The full Elkhorn Slough Tidal Marsh Restoration 
Project includes the anticipated restoration of 147 acres, but future 
phases are not part of this application because they would not likely 
occur for several years. If any future phase of the project would 
result in harassment of southern sea otters, another IHA would have to 
be requested and received prior to its implementation.
    A detailed description of the proposed project is contained in the 
incidental harassment authorization request submitted to us by CDFW 
(ESA/ESNERR 2016). CDFW submitted revised versions of the application 
on July 26, 2016, August 24, 2016, August 29, 2016, and September 6, 
2016. A final version, submitted on September 15, 2016, was determined 
to be adequate and complete. Work would begin between January 2017 and 
June 2017 and require approximately 11 months to complete. This period 
includes buffers for adverse weather and other conditions when work is 
not possible. Construction activities are expected to produce noise and 
visual disturbance that have the potential to result in behavioral 
harassment of southern sea otters. We are proposing to authorize take, 
by Level B harassment only, of southern sea otters as a result of the 
specified activity.

[[Page 6629]]

Description of the Activity

    The proposed project would restore approximately 47 acres of tidal 
marsh within the Minhoto-Hester Marsh area and additional tidal marsh, 
upland ecotone, and native grassland in a buffer area, intended to 
absorb upland sediment and contaminants, between the remnant marsh and 
agricultural fields. Approximately 170,000 cubic yards of fill would be 
required to raise the marsh plain an average height of 2.4 feet, or 1.9 
feet after 1 year of soil consolidation. The entire remnant marsh plain 
would be raised to an elevation that would allow emergent wetland 
vegetation to reestablish naturally and persist.
    The buffer area would be graded to increase marsh area and to 
create a gently sloping ecotone band along the edge of the restored 
marsh. Excavation would widen the existing marsh by up to 150 feet and 
create a band of gentle slope on the hillside, fostering creation of a 
wider ecotone habitat. A 35-acre portion of the buffer area would be 
restored to native-dominated perennial grassland. A weed-resistant 
border of rhizomatous perennial plants would be planted between the 
grassland and ecotone. The remaining 6-acre portion of the buffer area 
would be used as a stockpile location for future restoration phases and 
would be revegetated with annual barley until future phases were 
complete, at which time it would be restored to native-dominated 
perennial grassland.
    Remnant historic channels onsite would generally be left in place 
or filled and re-excavated in the same place. Smaller channels would be 
filled as needed for marsh access. As much of the existing tidal 
channel network would be maintained as feasible, and the post-project 
channel alignments would be similar to those under existing conditions. 
The density of channels (length of channel per acre of marsh) after 
restoration would be comparable to the density in natural reference 
marshes.
    Low levees (less than 0.5 feet above the marsh plain) composed of 
fill material would be constructed along the larger channels to 
simulate natural channel levees. The project would re-create natural 
levee features along the sides of the main channel into the Minhoto-
Hester area. Fill would be placed as close to the edge of the channel 
as possible to simulate the form and function of a natural channel 
bank. Borrow ditches that date from the times of historical wetland 
reclamation in these areas would be blocked or filled completely if 
fill is available after raising the marsh plain. Blocking borrow 
ditches would route more flow through the natural channels and slightly 
increase hydraulic resistance, which may achieve benefits from reducing 
tidal prism and associated scour in the Elkhorn Slough system.
    Construction sequencing would begin with water management and/or 
turbidity control measures constructed around the work areas prior to 
placing material on the marsh. Work areas on the remnant marsh plain 
would for the most part be isolated from the tides and dewatered to 
allow construction to occur in non-tidal conditions. Water control 
structures such as temporary berms would be utilized to isolate the 
fill placement area during the construction period. Existing berms 
would be used where possible. It is likely that the mouth of the 
restoration area could be closed with an earthen dam or an inflatable 
dam; however, a sheet pile wall at the mouth of the restoration area 
could be installed using vibratory hammering if the earthen and 
inflatable dam options proved to be infeasible. Tidal channels into 
work areas would be blocked. The isolated work areas would be drained 
using a combination of gravity and pumps. Water levels within the 
blocked areas would be managed to keep them mostly free of water (with 
some ponded areas remaining) to allow fill placement at all stages of 
the tides. Blocking of tidal channels would occur at low tide. Upon 
completion of sediment placement, the berms would be lowered to the 
target marsh elevation, reintroducing tidal inundation. Any blocked 
tidal channels would be re-excavated. After fill placement on the 
marsh, any temporary features, such as water management berms, sheet 
piles, and culverts, would be removed.
    All material needed for the current phase of the project is onsite. 
Additional material may be delivered to the restoration areas by trucks 
if it becomes available. Construction crews and equipment would access 
the existing stockpile area and Minhoto Marsh from Dolan Road via 
existing roadways that were used for delivery of the existing sediment 
stockpile, located alongside existing agricultural fields. The Hester 
Marsh staging area may be accessed from Via Tanques Road.
    Construction equipment would include haul trucks, heavy earthmoving 
equipment (such as bulldozers, backhoes, and loaders), and excavators 
to transport dry material out onto the marsh. A conveyor system could 
be used to transport material from a stockpile out to the marsh in lieu 
of bulldozers. In such cases, timber matting would be temporarily 
placed on the marsh to provide a stable footing for the conveyors. A 
mobile radial stacker at the end of the conveyor belt would be rotated 
to spread the material.

a. Timing of Activity

    Construction is anticipated to require approximately 11 months. The 
11-month window would include 132 days of construction activity and (if 
needed) 4 days of vibratory pile driving, totaling 136 days of project 
activity. The 11-month window includes the time required for ecotone 
and grassland restoration work. Most work on the marsh plane would 
likely be completed within 6 to 8 months. The length of the 
construction period is based on the assumption that construction 
contractors would work between the hours of 5:00 a.m. to 6:00 p.m., 
Monday through Friday. However, some construction activity could also 
be required during these times on Saturdays. The proposed IHA would be 
valid for 1 year from the date of issuance, with project activities 
beginning between January 2017 and June 2017.

b. Geographic Location of Activity

    The proposed project is located in the Elkhorn Slough estuary, a 
network of intertidal marshes, mudflats, and subtidal channels 90 miles 
south of San Francisco and 20 miles north of Monterey (see Figure 1-1 
of ESA/ESNERR 2016). The Minhoto-Hester Marsh, where the proposed 
restoration work would occur, is a low-lying area within Elkhorn Slough 
consisting of subsided pickleweed (Salicornia pacifica) marsh, 
intertidal mudflats, tidal channels, and remnant levees. The project 
area is on land owned and managed by CDFW as part of the Elkhorn Slough 
National Estuarine Research Reserve (ESNERR) (see Figure 1-2 of ESA/
ESNERR 2016). One Marine Protected Area (MPA), a State Marine Reserve, 
partially overlaps with the project area. Two additional MPAs are 
located within 1 mile of the project area. The Minhoto-Hester Marsh has 
multiple cross-levees and both natural and dredged channels, with a 
major dredged channel (exceeding 100 feet in width in some locations) 
that runs north to south through the remnant marsh.

Description of Marine Mammals in the Area of the Activity

    Southern sea otters and Pacific harbor seals (Phoca vitulina 
richardii) are present in or near the project site. Pacific harbor 
seals are under the jurisdiction of the National Marine Fisheries 
Service (NMFS) and are

[[Page 6630]]

considered under a separate proposed IHA notice. Therefore, we do not 
address them further here. The only marine mammal species under the 
jurisdiction of the Service that occurs in the proposed project area is 
the southern sea otter.
    Southern sea otters are listed as threatened under the Endangered 
Species Act of 1973, as amended (ESA) (42 FR 2965; January 14, 1977), 
and, because of their threatened status, are considered ``depleted'' 
under the MMPA. The State of California also recognizes the sea otter 
as a fully protected mammal (Fish and Game Code section 4700) and as a 
protected marine mammal (Fish and Game Code section 4500). All members 
of the sea otter population in California are descendants of a small 
group that survived the fur trade and persisted near Big Sur, 
California. Historically ranging from at least as far north as Oregon 
(Valentine et al. 2008) to Punta Abreojos, Baja California, Mexico, in 
the south, sea otters currently occur in only two areas of California. 
The mainland population ranges from San Mateo County to Santa Barbara 
County, and a translocated population exists at San Nicolas Island, 
Ventura County. The most recent (2016) California-wide index of 
abundance is 3,272 individuals (www.werc.usgs.gov/seaottercount). 
Additional general information on status and trends of the southern sea 
otter may be found in the stock assessment report, available at http://www.fws.gov/ventura/endangered/species/info/sso.html.
    Sea otters occur in Elkhorn Slough year round. As many as 150 sea 
otters (mostly male) raft together in the harbor at the mouth of 
Elkhorn Slough, and more than 50 females and pups, and a few 
territorial males, utilize protected tidal creeks and adjacent waters 
further up the slough (Scoles et al. 2012). Sea otters occur in the 
harbor, in tidal channels, and where eelgrass (Zostera marina) is 
present. Seal Bend, which is located approximately 0.8 river miles west 
of the proposed project area, is an important area for sea otter 
activity due to the large patch of eelgrass present there. When not 
disturbed, sea otters also frequently come ashore to rest, interact, 
and groom (Scoles et al. 2012).
    Sea otters use areas within the project footprint minimally (ESA/
ESNERR 2016; USGS, Monterey Bay Aquarium, and ESNERR unpublished data). 
A maximum of two sea otters at any one time were observed within the 
project footprint during pre-project monitoring conducted in 2013 (Beck 
2014). These animals were observed resting in water in area M3 of 
Minhoto Marsh (see Figure 4-2 of ESA/ESNERR 2016) when tidal heights 
were approximately 4 feet or higher. The maximum length of time a sea 
otter was observed in M3 during any monitoring session was 1.5 hours 
(Beck 2014).
    Up to 50 southern sea otters may be present in the area in and 
around Minhoto Marsh, Parsons Slough, Yampah Marsh, and the portion of 
Elkhorn Slough Channel that could be exposed to construction-related 
noise or disturbance (ESA/ESNERR 2016). Three main sea otter resting 
locations occur in these areas: One in the Parsons Slough Complex near 
the Avila Property and two near Yampah Island, southwest of the Union 
Pacific Railroad Bridge (see Figure 4-3 of ESA/ESNERR 2016; note that 
one marker is used to represent the two Yampah Island resting areas, 
which are located immediately to the west and east of its location on 
the map). Each of these areas consists of a territorial male and 
females with or without pups. Up to 35 sea otters were observed within 
the Parsons Slough Complex and Yampah Marsh during monitoring for an 
earlier project (ESNERR 2011). The closest area of concentrated sea 
otter activity to the project footprint is in Yampah Marsh, 
approximately 800 feet to the northeast (ESA/ESNERR 2016). The Yampah 
Marsh area is used heavily by females with and without pups for 
resting, hauling out, grooming, and (for females with pups) nursing 
(ESA 2016; USGS, Monterey Bay Aquarium, and ESNERR unpublished data).

Potential Impacts of the Proposed Action on Sea Otters

    In this section we provide a qualitative discussion of the 
potential impacts of the proposed project. The ``Estimated Take by 
Incidental Harassment'' section later in this document includes a 
quantitative analysis of the number of individuals that may be taken by 
Level B harassment as a result of this activity. Sea otters that have 
been observed to use Minhoto Marsh would be prevented from accessing 
the area and would be displaced to other areas of Elkhorn Slough for 
the duration of the project. Sea otters using the marsh areas adjacent 
to the project site for resting and foraging would be exposed to 
construction noise and activity, which could deter them from using 
these areas and displace them to adjacent areas of Elkhorn Slough. If 
sheet pile (rather than an earthen dam or inflatable dam) is required 
to isolate the construction area from tidal waters, vibratory hammering 
would increase ambient noise levels at the site for 4 days. Noise 
generated by vibratory pile driving could cause sea otters that forage 
or rest in the portion of the main channel adjacent to the restoration 
area to relocate temporarily to nearby areas. Behavioral changes 
resulting from disturbance could include startle responses, the 
interruption of resting behaviors (while in water or hauled out on 
pickleweed), and changes in foraging patterns. Impacts of the proposed 
project are limited to behavioral disturbance that may reach the 
threshold of Level B harassment. These impacts could result from 
airborne noise and visual disturbance caused by the presence of 
construction equipment and workers over a period of 11 months and (if 
sheet pile installation is required) from underwater noise caused by 
vibratory pile driving over a 4-day period.
    Relatively little is known regarding the effects of noise on sea 
otters, but they have not been reported to be particularly sensitive to 
noise disturbance, especially in comparison to other marine mammals 
(Riedman 1983, 1984). Many marine mammals depend on acoustic cues for 
vital biological functions, such as orientation, communication, 
locating prey, and avoiding predators. However, sea otters are not 
known to use acoustic information to orient or to locate prey, nor are 
they known to communicate underwater. Ghoul and Reichmuth (2014) 
obtained aerial and underwater audiograms for a captive adult male sea 
otter and evaluated his hearing in the presence of noise. In air, the 
sea otter's hearing was similar to that of a sea lion (Zalophus 
californianus) but less sensitive to high-frequency (greater than 22 
kHz) and low-frequency (less than 2 kHz) sounds than terrestrial 
mustelids. Underwater, the sea otter's hearing was less sensitive than 
that of sea lions and other pinnipeds, particularly at frequencies 
below 1 kHz. Critical ratios were more than 10 dB above those measured 
in pinnipeds, suggesting that sea otters have a relatively poor 
capacity to detect acoustic signals in noise.
    Observed responses of wild sea otters to disturbance are highly 
variable, probably reflecting the level of noise and activity to which 
they have been exposed and become acclimated over time and the 
particular location and social or behavioral state of that individual 
(G. Bentall pers. comm. 2010). Sea otters appeared to be relatively 
undisturbed by pile driving activities in Elkhorn Slough during the 
construction of the Parsons Slough Sill (adjacent to the Minoto-Hester 
Marsh), with many showing no response to pile driving and generally 
reacting more strongly to passing vessels associated

[[Page 6631]]

with construction than to the sounds of machinery (ESNERR 2011). Sea 
otters in Elkhorn Slough are likely acclimated to loud noises, as they 
occupy an area near an active railroad track, which produces in-air 
sound levels comparable to those produced by the vibratory driving of H 
piles (ESNERR 2011). Approximately 15-20 trains pass through Elkhorn 
Slough each day within 400 feet of the easternmost portion of the 
project area (Vinnedge Environmental Consulting 2010). A vehicle 
dismantling and recycling yard is located approximately 300 feet from 
the project area.
    The proposed construction activity may generate airborne noise 
above ambient levels or create a visual disturbance (during typical 
construction hours/workdays) for a period of 11 months. However, only 
work in the northern and eastern portions of Minhoto Marsh would be 
expected to disturb sea otters due to their proximity to the adjacent 
areas used by sea otters. Work in these portions of the marsh would 
likely be accomplished within approximately 6 months (132 construction 
days). Airborne noise produced by heavy earth-moving equipment such as 
backhoes and front-end loaders may produce sound levels of 80-90 dB re 
20[mu]Pa at 50 feet (Federal Highway Administration 2015). Vibratory 
driving of steel sheet piles, which may occur during 4 of the 136 total 
days of construction, is expected to produce maximum airborne sound 
levels of 97 dBA re 20[mu]Pa at 33 feet and 90 dBA re 20[mu]Pa at 98 
feet (where dBA refers to dB with A-weighting designed to match the 
average frequency response of human hearing, which enables comparison 
of the intensity of noises with different frequency characteristics) 
(ESNERR 2011). Vibratory driving of sheet piles would generate 
underwater noise to which sea otters in the vicinity would be exposed 
while diving or performing other behaviors that cause immersion of the 
ears. However, because of acoustic shadowing due to the winding 
configuration of Elkhorn Slough, underwater sound transmission would be 
relatively limited. The likely extent of transmission of sound 
exceeding 120 dB re 1 [micro]Pa is pictured in Figure 6-4 of ESA/ESNERR 
(2016).
    NMFS employs acoustic exposure criteria to define Level A 
harassment (injury) and Level B harassment (disturbance) resulting from 
sound for the marine mammal species under its jurisdiction. For 
underwater non-impulsive noise (which includes vibratory pile driving 
and removal), NMFS uses 219 dB re 1 [micro]Pa (cumulative 24-hour sound 
exposure level) as the threshold for Level A harassment of otariid 
pinnipeds (e.g., sea lions) (NMFS 2016) and 120 dB re 1 [micro]Pa 
(received level) as the threshold for Level B harassment. For airborne 
noise, NMFS uses 100 dB re 20 [micro]Pa (received level) as a 
guideline, but not formal threshold, for the onset of Level B 
harassment for pinnipeds other than harbor seals (79 FR 13991; March 
12, 2014). NMFS does not have a guideline for the onset of Level A 
harassment of pinnipeds by airborne noise (A. Scholik-Schlomer, Office 
of Protected Resources, Marine Mammal and Sea Turtle Conservation 
Division, pers. comm. 2014). However, Southall et al. (2007) propose an 
injury criterion for sea lions exposed to airborne noise of 172.5 dB re 
20 [micro]Pa.
    In the absence of sufficient data on which to base noise exposure 
thresholds specific to sea otters, but in light of experimental 
evidence suggesting that the hearing sensitivities of sea lions and sea 
otters are generally comparable (although, as noted above, sea otter 
hearing appears to be less sensitive than sea lion hearing underwater), 
we use the thresholds, guidelines, and criteria applicable to sea lions 
as proxies. With regard to underwater noise, we use the thresholds 
adopted by NMFS for sea lions to evaluate whether noise exposure levels 
would constitute Level A or Level B harassment of sea otters. With 
regard to airborne noise, we use the guideline that NMFS uses for 
pinnipeds other than harbor seals to evaluate whether anticipated 
exposure levels resulting from this project would constitute Level B 
harassment of sea otters and the injury criterion proposed in Southall 
et al. (2007) for sea lions to evaluate whether the anticipated 
airborne noise exposures would constitute Level A harassment. 
Specifically, we use 219 dB re 1 [micro]Pa as the threshold for Level A 
harassment underwater and 120 dB re 1 [micro]Pa (for non-impulse 
sources) as the threshold for Level B harassment underwater. Similarly, 
we adopt for sea otters the 100 dB re 20 [micro]Pa guideline that NMFS 
uses for in-air Level B harassment of pinnipeds other than harbor 
seals. We use the Southall et al. (2007) criterion of 172.5 dB re 20 
[micro]Pa for sea lions to approximate the airborne noise levels that 
may cause injury to sea otters. Given that sea otters are not known to 
use sound to communicate underwater, to orient, or to locate prey, and 
given sea otters' decreased sensitivity to underwater noise relative to 
that of sea lions, we acknowledge that these thresholds are likely 
highly conservative. As additional behavioral or other data on sea 
otter responses to sound become available, we may determine that one or 
more of these thresholds are not applicable to sea otters.

Potential Effects of the Proposed Action on Sea Otter Habitat

    Habitat within the project footprint would be inaccessible to sea 
otters for the duration of construction. However, these impacts would 
be minimal, as past surveys documented a maximum of two sea otters 
using this area. Construction activity would result in a slight 
increased risk of accidental water contamination from equipment 
refueling, fluid leakage, or maintenance activities within or near 
water bodies. Leaks or spills of petroleum hydrocarbon products found 
in construction equipment could have adverse effects on sea otters by 
contaminating their fur (interfering with thermoregulation) and through 
ingestion during grooming. Vibratory pile driving (if required by the 
project) would not be expected to alter the availability of prey 
species to sea otters in the waters or marshlands adjacent to the 
project site because these species are largely sessile benthic 
invertebrates. The proposed action would permanently alter habitat 
within the footprint of the construction area, but the restoration of 
salt marsh would benefit sea otters over the longer term by providing 
additional high-quality habitat within Elkhorn Slough for hauling out 
and foraging.

Potential Impacts on Subsistence Needs

    The subsistence provision of the MMPA does not apply.

Mitigation Measures

    CDFW has proposed the following measures to prevent Level A 
harassment (injury) and to reduce the extent of potential effects from 
Level B harassment (disturbance) to marine mammals.
    1. A Service- and NMFS-approved biologist would conduct mandatory 
biological resources awareness training for construction personnel. The 
awareness training would be provided to all construction personnel to 
brief them on the need to avoid effects on marine mammals. If new 
construction personnel are added to the project, the contractor would 
ensure that the personnel receive the mandatory training before 
starting work.
    2. A biological monitor approved by the Service and NMFS would 
monitor for marine mammal disturbance. Monitoring would occur at all 
times when work is occurring: (a) In water, (b) north of a line 
starting at 36[deg]48'38.91 N. 121[deg]45'08.03 W. and ending 
36[deg]48'38.91 N. 121[deg]45'27.11 W., or (c) within 100

[[Page 6632]]

feet of tidal waters. When work is occurring in other areas, monitoring 
would be implemented for at least the first 3 days of construction. 
Monitoring would continue until there are 3 successive days of no 
observed disturbance, at which point monitoring would be suspended. 
Monitoring would resume when there is a significant change in 
activities or location of activities within the project area or if 
there is a gap in construction activities of more than 1 week. In these 
cases, monitoring would again be implemented for at least the first 3 
days of construction and would not be suspended until there are 3 
successive days of no observed disturbance. The biological monitor 
would have the authority to stop project activities if marine mammals 
approach or enter the exclusion zone. Biological monitoring would begin 
0.5-hour before work begins and will continue until 0.5-hour after work 
is completed each day. Work would commence only with approval of the 
biological monitor to ensure that no marine mammals are present in the 
exclusion zone.
    3. To reduce the risk of potentially startling marine mammals with 
a sudden intensive sound, the construction contractor would begin 
construction activities gradually each day by moving around the project 
area and starting tractors one at a time.
    4. Biological monitors would have authority to stop construction at 
any time for the safety of any marine mammals.
    5. In-water construction work would occur only during daylight 
hours when visual monitoring of marine mammals can be implemented. No 
in-water work would be conducted at night.
    6. If sheet piles are used to isolate construction activities from 
tidal action, all piles would be installed using a vibratory pile 
driver, and an exclusion zone would be implemented. Because the area 
within which underwater sound pressure levels are expected to reach or 
exceed 190 dB re 1 [mu]Pa is less than a foot, the radius of the 
exclusion zone would be set at a minimum of 49 feet to prevent the 
injury of marine mammals from machinery. Pile extraction or driving 
would not commence (or re-commence following a shutdown) until marine 
mammals are not sighted within the exclusion zone for a 15-minute 
period. If a marine mammal enters the exclusion zone during sheet pile 
work, work would stop until the animal leaves the exclusion zone.
    7. If marine mammals are present within the work area, they would 
be allowed to leave on their own volition. If they are not leaving the 
work area on their own, coordination with NMFS or the Service (as 
appropriate) would occur to ensure a government official be present 
should an animal require flushing from within the footprint of the 
construction area.
    8. Fuel storage and all fueling and equipment maintenance 
activities would be conducted at least 100 feet from subtidal and 
intertidal habitat.

Monitoring and Reporting

    CDFW would follow a detailed monitoring plan developed in 
consultation with the Service and NMFS. A Service- and NMFS-approved 
biological monitor would monitor for marine mammal disturbance. 
Monitoring would occur as described in Mitigation Measure #2 above. 
Throughout construction activities that require a monitor, the 
biological monitor would maintain a log that documents numbers of 
marine mammals present before, during, and at the conclusion of daily 
activities. The monitor would record basic weather conditions and 
marine mammal behavior. A final report would be submitted to the 
Service and NMFS within 90 days of the conclusion of monitoring 
efforts. The report would detail the monitoring protocol, summarize the 
data recorded during monitoring, and contain an estimate of the number 
of marine mammals, by species, that may have been harassed.

Estimated Take by Incidental Harassment

    Based on the proposed construction methodology and mitigation, 
including use of an exclusion zone, no Level A harassment of southern 
sea otters is anticipated as a result of the proposed project. 
Anticipated received noise levels would remain well below the 
thresholds established for Level A harassment. Behavioral harassment 
(Level B) could result from visual disturbance and in-air noise of 100 
dB re 20 [mu]Pa or greater for a period of 132 days and (if pile 
driving is required by the project) visual disturbance, in-air noise of 
100 dB re 20 [mu]Pa or greater, and underwater continuous noise of 120 
dB re 1 [mu]Pa or greater for a period of 4 days.
    In order to quantify take that may occur incidental to the 
specified activity, we determine the area that may be subject to 
project-related disturbance, estimate the number of sea otters likely 
to be present in that area, and multiply the number of sea otters by 
the number of days they could be disturbed during the project. Because 
airborne noise attenuates rapidly, and because of the distance of the 
project site from areas of concentrated sea otter activity (the closest 
such area, Yampah Marsh, is approximately 800 feet away), it is likely 
that few sea otters will be exposed to noise levels exceeding the 100 
dB re 20 [mu]Pa threshold. The area potentially subject to visual 
disturbance from construction activity is larger than and inclusive of 
the area potentially exposed to airborne sound exceeding the threshold 
for Level B harassment. Accordingly, we do not evaluate the number of 
sea otters exposed to airborne noise separately from the number of sea 
otters exposed to visual disturbance.
    Vibratory pile driving (if required) would generate visual 
disturbance and in-air and underwater noise for a period of 4 days. The 
portion of Elkhorn Slough Channel that could be exposed to underwater 
noise of 120 dB re 1 [mu]Pa or greater during pile driving is pictured 
in Figure 6-4 of ESA/ESNERR (2016). An estimated 15 sea otters may use 
this portion of the channel for foraging or traveling from one location 
to another. The area that could potentially be affected by visual 
disturbance and in-air noise of 100 dB re 20 [mu]Pa or greater during 
pile driving includes Minhoto Marsh, Parsons Slough, and Yampah Marsh, 
which are utilized by an average of 35 sea otters (ESA/ESNERR 2016). Up 
to 50 sea otters may be present on land or in water and potentially 
affected by vibratory pile driving for 4 days, resulting in an 
estimated 200 instances of take.
    After sheet piles are installed (or if an earthen dam or an 
inflatable dam is used instead), the project site would be isolated 
from aquatic areas, and sea otters would no longer be able to access 
the work area. At that time, sea otters outside of the work area would 
be subject to reduced levels of disturbance. An average of 10 sea 
otters per day (a subset of the 50 that may be affected by vibratory 
pile driving) could be affected by visual disturbance and in-air noise 
of 100 dB re 20 [mu]Pa or greater during the subsequent 132 days of 
construction work in the northern and eastern portions of the Minhoto 
Marsh, resulting in approximately 1,320 takes.

Findings

    We propose the following findings regarding this action:

Negligible Impact

    We find that any incidental take by harassment that is reasonably 
likely to result from the proposed project would not adversely affect 
the southern sea otter by means of effects on rates of recruitment or 
survival, and would, therefore, have no more than a negligible impact 
on the species or stock

[[Page 6633]]

(all southern sea otters are considered to belong to a single stock). 
In making this finding, we considered the best available scientific 
information, including: (1) The biological and behavioral 
characteristics of the species; (2) information on distribution and 
abundance of sea otters within the area of the proposed activity; (3) 
the potential sources of disturbance during the proposed activity; and 
(4) the potential response of sea otters to disturbance.
    The estimated 200 potential takes (affecting up to 50 sea otters 
per day) during a total of 4 days of vibratory pile driving, if 
required by the project, and 1,320 potential takes (affecting up to 10 
sea otters per day over a period of 132 days) during subsequent 
construction activity are expected to result in negligible impact for 
the following reasons: Received noise levels would remain well below 
the thresholds established for Level A harassment; sea otters do not 
appear to be particularly sensitive to noise (and often do not react 
visibly to it); and any behavioral reactions to noise or visual 
disturbance are expected to be temporary and of short duration. In 
particular, the estimate of the number of sea otters that could be 
harassed by exposure to project-related underwater sound based on the 
120 dB threshold may overstate impacts because this threshold is 
sometimes at or even below the ambient noise level in certain 
locations. Additionally, disturbance resulting from project activities 
would affect only a small portion of the sea otter habitat available to 
and used by sea otters in Elkhorn Slough.
    The mitigation measures outlined above are intended to minimize the 
number of sea otters that could be disturbed by the proposed activity. 
Any impacts to individuals are expected to be limited to Level B 
harassment of short duration. Responses of sea otters to disturbance 
would most likely be common behaviors such as diving and/or swimming 
away from the source of the disturbance. No take by injury or death is 
anticipated. Because any Level B harassment that occurs would be of 
short duration, and because no take by injury or death is anticipated, 
we find that the anticipated harassment caused by the proposed 
activities is not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival.
    Our finding of negligible impact applies to incidental take 
associated with the proposed activity as mitigated through this 
authorization process. This authorization establishes monitoring and 
reporting requirements to evaluate the potential impacts of the 
authorized activities, as well as mitigation measures designed to 
minimize interactions with, and impacts to, sea otters.

Small Numbers

    For small numbers take analysis, the statute and legislative 
history do not expressly require a specific type of numbers analysis, 
leaving the determination of ``small'' to the agency's discretion. The 
sea otter population in California consists of approximately 3,272 
animals. The number of sea otters that could potentially be taken by 
harassment in association with the proposed project, approximately 50 
animals, is 1.5 percent of the population size. We find that the number 
of sea otters utilizing the affected area is small relative to the size 
of the population.

Impact on Subsistence

    The subsistence provision of the MMPA does not apply to southern 
sea otters.

Endangered Species Act

    The proposed activity will occur within the range of the southern 
sea otter, which is listed as threatened under the ESA. CDFW has 
requested a Pre-Construction Notification (PCN) under U.S. Army Corps 
of Engineers' (Corps') Nationwide Permit (NWP) 27 (USACE 2012). The 
Corps has initiated interagency consultation under section 7 of the ESA 
with the Service's Ventura Fish and Wildlife Office. We will also 
complete intra-Service section 7 consultation on our proposed issuance 
of the IHA.

National Environmental Policy Act (NEPA)

    The types of impacts associated with aquatic habitat restoration, 
establishment, and enhancement activities are described in NWP 27. The 
analyses in the NWP and the coordination undertaken prior to its 
issuance fulfill the requirements of NEPA (42 U.S.C. 4321 et seq.). The 
Service will review the Decision Document for NWP 27 and decide either 
to adopt it or to prepare its own NEPA document before making a 
determination on the issuance of an IHA. Our analysis will be completed 
prior to issuance or denial of the IHA and will be available at http://www.fws.gov/ventura/endangered/species/info/sso.html.

Government-To-Government Relations With Native American Tribal 
Governments

    In accordance with the President's memorandum of April 29, 1994, 
``Government-to-Government Relations with Native American Tribal 
Governments'' (59 FR 22951), Executive Order 13175, Secretarial Order 
3206, Department of the Interior Secretarial Order 3317 of December 1, 
2011 (Tribal Consultation and Policy), the Department of the Interior's 
manual at 512 DM 2, and the Native American Policy of the Service, 
January 20, 2016, we readily acknowledge our responsibility to 
communicate meaningfully with federally recognized Tribes on a 
Government-to-Government basis. We have evaluated possible effects on 
federally recognized Indian Tribes and have determined that there are 
no effects.

Proposed Authorization

    The Service proposes to issue CDFW an IHA for the nonlethal, 
incidental, unintentional take by level B harassment of small numbers 
of southern sea otters while the applicant is completing the Minhoto-
Hester Marsh Restoration Project in Elkhorn Slough, Monterey County, 
California. The 1-year authorization would begin on the date of 
issuance, with an anticipated project start date between January 2017 
and June 2017. Authorization for incidental take beyond the 1-year 
period would require a request for renewal.
    The final IHA would incorporate the mitigation, monitoring, and 
reporting requirements discussed in this proposal. The applicant would 
be responsible for following those requirements. This authorization 
would not allow the intentional taking of sea otters, nor take by 
injury or death.
    If the level of activity exceeded that described by the applicant, 
or the level or nature of take exceeded those projected here, the 
Service would reevaluate its findings. The Secretary may modify, 
suspend, or revoke an authorization if the findings are not accurate or 
the mitigation, monitoring, and reporting requirements described in 
this notice are not being met.

Request for Public Comments

    The Service requests that interested persons submit comments and 
information concerning this proposed IHA. For information on the 
references cited in this notice, see ADDRESSES.
    Consistent with section 101(a)(5)(D)(iii) of the MMPA, we are 
opening the comment period on this proposed authorization for 30 days 
(see

[[Page 6634]]

DATES). We intend any final action resulting from this proposal to be 
as accurate and as effective as possible. Therefore, we request 
comments or suggestions on this proposed authorization.
    We particularly seek comments concerning:
     Whether the proposed authorization, including the proposed 
activities, will have a negligible impact on the species or stock of 
the southern sea otter.
     Whether there are any additional provisions we may wish to 
consider for ensuring the conservation of the southern sea otter.
    You may submit your comments and materials concerning this proposed 
authorization by one of the methods listed in ADDRESSES. Before 
including your address, phone number, email address, or other personal 
identifying information in your comment, you should be aware that your 
entire comment--including your personal identifying information--may be 
made publicly available at any time. While you can ask us in your 
comment to withhold your personal identifying information from public 
review, we cannot guarantee that we will be able to do so.

    Authority:  We issue this notice under the authority of the MMPA 
(16 U.S.C. 1371 et seq.).

    Dated: January 6, 2017.
Paul Souza,
Regional Director, Pacific Southwest Region.
[FR Doc. 2017-01271 Filed 1-18-17; 8:45 am]
 BILLING CODE 4333-15-P