Federal Register Vol. 83, No.36,

The Animal and Plant Health Inspection Service (APHIS) is proposing to issue permits for the release of a mite, Aceria drabae, into the continental United States for use as a biological control agent to reduce the severity of hoary cress infestations.

On December 5, 2017, we published in the Federal Register (82 FR 57424-57425, Docket No. APHIS-2017-0086) a notice 1 in which we announced the availability, for public review and comment, of an environmental assessment (EA) that examined the potential environmental impacts associated with the proposed release of this biological control agent into the continental United States.

We solicited comments on the EA for 30 days ending January 4, 2018. We received one comment by the close of the comment period. The commenter was generally opposed to the release of insects for biological control but did not raise any specific or substantive issues.

In this document, we are advising the public of our finding of no significant impact (FONSI) regarding the release of Aceria drabae into the continental United States for use as a biological control agent to reduce the severity of hoary cress infestations. The finding, which is based on the EA, reflects our determination that release of this biological control agent will not have a significant impact on the quality of the human environment.

The EA and FONSI may be viewed on the Regulations.gov website (see footnote 1). Copies of the EA and FONSI are also available for public inspection in our reading room, which is located in room 1141 of the USDA South Building, 14th Street and Independence Avenue SW, Washington, DC. Normal reading room hours are 8 a.m. to 4:30 p.m., Monday through Friday, except holidays. To be sure someone is there to help you, please call (202) 799-7039 before coming. In addition, copies may be obtained by calling or writing to the individual listed under FOR FURTHER INFORMATION CONTACT.

The EA and FONSI have been prepared in accordance with: (1) The National Environmental Policy Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), (2) regulations of the Council on Environmental Quality for implementing the procedural provisions of NEPA (40 CFR parts 1500-1508), (3) USDA regulations implementing NEPA (7 CFR part 1b), and (4) APHIS' NEPA Implementing Procedures (7 CFR part 372).

Interested members of the public may listen to the discussion by calling the following toll-free conference call number: 1-800-310-7032 and conference call ID: 2757439. Please be advised that before placing them into the conference call, the conference call operator may ask callers to provide their names, their organizational affiliations (if any), and email addresses (so that callers may be notified of future meetings). Callers can expect to incur charges for calls they initiate over wireless lines, and the Commission will not refund any incurred charges. Callers will incur no charge for calls they initiate over land-line connections to the toll-free telephone number herein.

Persons with hearing impairments may also follow the discussion by first calling the Federal Relay Service at 1-800-877-8339 and providing the operator with the toll-free conference call number: 1-800-310-7032 and conference call ID: 2757439.

Members of the public are invited to submit written comments; the comments must be received in the regional office approximately 30 days after each scheduled meeting. Written comments may be mailed to the Eastern Regional Office, U.S. Commission on Civil Rights, 1331 Pennsylvania Avenue, Suite 1150, Washington, DC 20425, or emailed to Evelyn Bohor at [email protected]. Persons who desire additional information may contact the Eastern Regional Office at (202) 376-7533.

Records and documents discussed during the meeting will be available for public viewing as they become available at https://www.facadatabase.gov/committee/meetings.aspx?cid=272; click the “Meeting Details” and “Documents” links. Records generated from this meeting may also be inspected and reproduced at the Eastern Regional Office, as they become available, both before and after the meetings. Persons interested in the work of this advisory committee are advised to go to the Commission's website, www.usccr.gov, or to contact the Eastern Regional Office at the above phone number, email or street address.

On October 23, 2017, the Department of Commerce (Commerce) initiated antidumping duty (AD) investigations on polyethylene terephthalate resin from Brazil, Indonesia, the Republic of Korea, Pakistan, and Taiwan.1 Commerce exercised its discretion to toll all deadlines affected by the closure of the Federal Government from January 20 through 22, 2018. If the new deadline falls on a non-business day, in accordance with Commerce's practice, the deadline will become the next business day. Accordingly, the current deadline for the preliminary determinations of these investigations is March 8, 2018.

Section 733(b)(1)(A) of the Tariff Act of 1930, as amended (the Act), requires Commerce to issue the preliminary determination in an AD investigation within 140 days after the date on which Commerce initiated the investigation. However, section 733(c)(1)(A) of the Act and 19 CFR 351.205(e) allow Commerce to postpone the preliminary determination at the request of the petitioner.

On January 29, 2018, the petitioners 2 submitted a timely request pursuant to 19 CFR 351.205(e) to postpone the preliminary determinations.3 They noted that Commerce is still gathering data and questionnaire responses from the foreign producers in these investigations and additional time is necessary for Commerce and interested parties to fully and properly analyze all questionnaire response.4 For these reasons, and because there are no compelling reasons to deny the request, Commerce, in accordance with section 733(c)(1)(A) of the Act and 19 CFR 351.205(e), is postponing the deadline for the preliminary determinations to no later than 190 days after the day on which the investigations were initiated. Accordingly, Commerce will issue the preliminary determinations no later than April 27, 2018, a date that has been adjusted for the period of the closure of the Federal Government. In accordance with section 735(a)(1) of the Act and 19 CFR 351.210(b)(1), the deadline for the final determinations of these investigations will continue to be 75 days after the date of the preliminary determinations, unless postponed.

This notice is issued and published pursuant to section 733(c)(2) of the Act and 19 CFR 351.205(f)(1).

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.

An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth.

NMFS has defined “negligible impact” in 50 CFR 216.103 as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.

The MMPA states that the term “take” means to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal.

Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as: Any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

To comply with the National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, NMFS must review our proposed action (i.e., the issuance of an incidental harassment authorization) with respect to potential impacts on the human environment.

Accordingly, NMFS is preparing an Environmental Assessment (EA) to consider the environmental impacts associated with the issuance of the proposed IHA. We will review all comments submitted in response to this notice prior to concluding our NEPA process or making a final decision on the IHA request.

On November 9, 2017, NMFS received a request from Statoil for an IHA to take marine mammals incidental to marine site characterization surveys off the coast of New York as part of the Empire Wind Project in the area of the Commercial Lease of Submerged Lands for Renewable Energy Development on the Outer Continental Shelf (OCS-A 0512) and coastal waters where one or more cable route corridors will be established. A revised application was received on January 8, 2018. NMFS deemed that request to be adequate and complete. Statoil's request is for take of 11 marine mammal species by Level B harassment. Neither Statoil nor NMFS expects serious injury or mortality to result from this activity and the activity is expected to last no more than one year, therefore, an IHA is appropriate.

Statoil proposes to conduct marine site characterization surveys including high-resolution geophysical (HRG) and geotechnical surveys in the marine environment of the approximately 79,350-acre Lease Area located approximately 11.5 nautical miles (nm) from Jones Beach, New York (see Figure 1 in the IHA application). Additionally, one or more cable route corridors will be established between the Lease Area and New York, identified as the Cable Route Area (see Figure 1 in the IHA application). See the IHA application for further information. Cable route corridors are anticipated to be 152 meters (m, 500 feet (ft)) wide and may have an overall length of as much as 135 nm. For the purpose of this IHA, the survey area is designated as the Lease Area and cable route corridors that will be established in advance of conducting the HRG survey activity. Water depths across the Lease Area range from approximately 22 to 41 m (72 to 135 ft) while the cable route corridors will extend to shallow water areas near landfall locations. Surveys would occur from approximately March 2018 through July 2018.

The purpose of the marine site characterization surveys are to support the siting, design, and deployment of up to three meteorological data buoy deployment areas and to obtain a baseline assessment of seabed/sub-surface soil conditions in the Lease Area and cable route corridors to support the siting of the proposed wind farm. Underwater sound resulting from Statoil's proposed site characterization surveys have the potential to result in incidental take of marine mammals in the form of behavioral harassment.

Surveys will last for approximately 20 weeks and are anticipated to commence upon issuance of the requested IHA, if appropriate. This schedule is based on 24-hour operations and includes potential down time due to inclement weather. Based on 24-hour operations, the estimated duration of the HRG survey activities would be approximately 142 days (including estimated weather down time).

Statoil's survey activities will occur in the approximately 79,350-acre Lease Area located approximately 11.5 nm from Jones Beach, New York (see Figure 1 in the IHA application). Additionally, one or more cable route corridors would be surveyed between the Lease Area and New York. Cable route corridors are anticipated to be 152 meters (m, 500 ft) wide and may have an overall length of as much as 135 nm.

Statoil's proposed marine site characterization surveys include HRG and geotechnical survey activities. These activities are described below.

The HRG survey activities proposed by Statoil would include the following:

• Depth sounding (multibeam echosounder) to determine site bathymetry and elevations;

• Magnetic intensity measurements for detecting local variations in regional magnetic field from geological strata and potential ferrous objects on and below the bottom;

• Seafloor imaging (sidescan sonar survey) for seabed sediment classification purposes, to identify natural and man-made acoustic targets resting on the bottom as well as any anomalous features;

• Shallow penetration sub-bottom profiler (pinger/chirp) to map the near surface stratigraphy (top 0 to 5 m (0 to 16 ft) of soils below seabed);

• Medium penetration sub-bottom profiler (sparker) to map deeper subsurface stratigraphy as needed (soils down to 75 to 100 m (246 to 328 ft) below seabed); and

• Ultra short baseline positioning system (USBL) for position referencing for the dynamic positioning (DP) vessel.

Table 1 identifies the representative survey equipment that may be used in support of planned HRG survey activities. The make and model of the listed HRG equipment will vary depending on availability but will be finalized as part of the survey preparations and contract negotiations with the survey contractor. The final selection of the survey equipment will be confirmed prior to the start of the HRG survey program. Any survey equipment selected would have characteristics similar to the systems described below, if different.

The HRG survey activities would be supported by a vessel approximately 30 to 55 m (98 to 180 ft) in length and capable of maintaining course and a survey speed of approximately 4 nm per hour (7.4 kilometers per hour (km/hr)) while transiting survey lines. Surveys would be conducted along tracklines spaced 30 m (98 ft) apart, with tie-lines spaced every 500 m (1640 ft). The multichannel array sub-bottom profiler would be operated on 150-m (492-ft) spaced primary lines, while the single channel array sub-bottom profiler would be operated on 30-m (98-ft) line spacing to meet Bureau of Ocean Energy Management (BOEM) requirements as set out in BOEM's Guidelines for Providing Geophysical, Geotechnical, and Geohazard Information Pursuant to Archeological and Historic Property Information to 30 CFR part 585.

To minimize cost, the duration of survey activities, and the period of potential impact on marine species while surveying, Statoil has proposed that HRG survey operations would be conducted continuously 24 hours per day. Based on 24-hour operations, the estimated duration of the HRG survey activities would be approximately 142 days (including estimated weather down time) including 123 survey days in the Lease Area and 19 survey days in the cable route corridors.

The deployment of HRG survey equipment, including the equipment planned for use during Statoil's planned activity, produces sound in the marine environment that has the potential to result in harassment of marine mammals. Based on the frequency ranges of the potential equipment planned to be used in support of HRG survey activities (Table 1) the ultra-short baseline (USBL) positioning system and the sub-bottom profilers (shallow and medium penetration) operate within functional marine mammal hearing ranges and have the potential to result in harassment of marine mammals.

Statoil's proposed geotechnical survey activities would include the following:

• Vibracores would be taken to determine the geological and geotechnical characteristics of the sediments; and

• Cone Penetration Testing (CPT) would be performed to determine stratigraphy and in-situ conditions of the sediments.

Statoil's proposed geotechnical survey activities would begin no earlier than March 2018 and would last up to 30 days. It is anticipated that geotechnical surveys would entail sampling of vibracores and CPT. A sample would be taken approximately every one kilometer (km) along the selected cable route, alternating between CPTs and vibracores, such that intervals for each vibracore and CPT location would be approximately 2 km. Precise cable routes were not known at the time the IHA application was submitted. As many as three cable routes may be identified for geotechnical sampling, with cable routes likely to range in length from 20 km to 65 km. Assuming a maximum, minimum, and median route length for the three potential cable corridors, the total length of survey corridor would be approximately 128 km. Therefore it is anticipated that approximately 128 locations would be sampled (approximately one sample taken per km), located equidistant between the lease area and the New York shoreline (as depicted in Figure 1 of the IHA Application as the Cable Route Area). The duration of each sampling event would take approximately 2-4 hours and geotechnical survey activities would occur 24 hours per day during the survey. Statoil anticipates a production rate of approximately 5 samples per day.

In considering whether marine mammal harassment is an expected outcome of exposure to a particular activity or sound source, NMFS considers both the nature of the exposure itself (e.g., the magnitude, frequency, or duration of exposure) and the conditions specific to the geographic area where the activity is expected to occur (i.e., whether the activity is planned in a foraging area, breeding area, nursery or pupping area, or other biologically important area for the species). We then consider the expected response of the exposed animal and whether the nature and duration or intensity of that response is expected to cause disruption of behavioral patterns (e.g., migration, breathing, nursing, breeding, feeding, or sheltering) or injury.

Geotechnical survey activities would be conducted from a drill ship equipped with DP thrusters. DP thrusters would be used to position the sampling vessel on station and maintain position at each sampling location during the sampling activity. A ship has not yet been assigned to conduct the survey, but Statoil anticipates that survey activities would likely be conducted from a typical offshore sampling vessel, ranging from 250ft to 350ft (76 m to 107 m). Sound produced through use of DP thrusters is similar to that produced by transiting vessels and DP thrusters are typically operated in a similarly predictable manner. NMFS does not believe acoustic impacts from DP thrusters are likely to result in take of marine mammals in the absence of activity- or location-specific circumstances that may otherwise represent specific concerns for marine mammals (i.e., activities proposed in area known to be of particular importance for a particular species), or associated activities that may increase the potential to result in take when in concert with DP thrusters, largely due to the low likelihood of marine mammal behavioral response to DP thrusters that would rise to the level of a take (versus less consequential behavioral reactions). In this case, we are not aware of any such circumstances. Monitoring of past projects that entailed use of DP thrusters has shown a lack of observed marine mammal responses as a result of exposure to sound from DP thrusters. Therefore, NMFS believes the likelihood of DP thrusters used during the proposed geotechnical surveys resulting in harassment of marine mammals to be so low as to be discountable. As DP thrusters are not expected to result in take of marine mammals, these activities are not analyzed further in this document.

Vibracoring entails driving a hydraulic or electric pulsating head through a hollow tube into the seafloor to recover a stratified representation of the sediment. The vibracoring process is short in duration and is performed from a dynamic positioning vessel. The vessel would use DP thrusters to maintain the vessel's position while the vibracore sample is taken, as described above. The vibracoring process would always be performed in concert with DP thrusters, and DP thrusters would begin operating prior to the activation of the vibracore to maintain the vessel's position; thus, we expect that any marine mammals in the project area would detect the presence and noise associated with the vessel and the DP thrusters prior to commencement of vibracoring. Any reaction by marine mammals would be expected to be similar to reactions to the concurrent vessel noise, which are expected to be minor and short term. In this case, vibracoring is not planned in any areas of particular biological significance for any marine mammals. Thus while a marine mammal may perceive noise from vibracoring and may respond briefly, we believe the potential for this response to rise to the level of take to be so low as to be discountable, based on the short duration of the activity and the fact that marine mammals would be expected to react to the vessel and DP thrusters before vibracoring commences, potentially through brief avoidance. In addition, the fact that the geographic area is not biologically important for any marine mammal species means that such reactions are not likely to carry any meaningful significance for the animals.

Field studies conducted off the coast of Virginia to determine the underwater noise produced by CPTs found that these activities did not result in underwater noise levels that exceeded current thresholds for Level B harassment of marine mammals (Kalapinski, 2015). Given the small size and energy footprint of CPTs, NMFS believes the likelihood that noise from these activities would exceed the Level B harassment threshold at any appreciable distance is so low as to be discountable. Therefore, geotechnical survey activities, including CPT and vibracores, are not expected to result in harassment of marine mammals and are not analyzed further in this document.

Proposed mitigation, monitoring, and reporting measures are described in detail later in this document (please see “Proposed Mitigation” and “Proposed Monitoring and Reporting”).

Sections 3 and 4 of Statoil's IHA application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history, of the potentially affected species. Additional information regarding population trends and threats may be found in NMFS's Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical and behavioral descriptions) may be found on NMFS's website (www.nmfs.noaa.gov/pr/species/mammals/).

Table 2 lists all species with expected potential for occurrence in the survey area and summarizes information related to the population or stock, including regulatory status under the MMPA and ESA and potential biological removal (PBR), where known. For taxonomy, we follow Committee on Taxonomy (2017). PBR is defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population (as described in NMFS's SARs). While no mortality is anticipated or authorized here, PBR is included here as gross indicators of the status of the species 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's 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's U.S. 2017 draft SARs (e.g., Hayes et al., 2018). All values presented in Table 2 are the most recent available at the time of publication and are available in the 2017 draft SARs (Hayes et al., 2018).

All species that could potentially occur in the proposed survey areas are included in Table 2. However, the temporal and/or spatial occurrence of 26 of the 37 species listed in Table 2 is such that take of these species is not expected to occur, and they are not discussed further beyond the explanation provided here. Take of these species is not anticipated either because they have very low densities in the project area, are known to occur further offshore than the project area, or are considered very unlikely to occur in the project area during the proposed survey due to the species' seasonal occurrence in the area.

Three marine mammal species are listed under the Endangered Species Act (ESA) and are known to be present, at least seasonally, in the survey area and are included in the take request: North Atlantic right whale, fin whale, and sperm whale.

Below is a description of the species that are both common in the survey area southeast of New York and that have the highest likelihood of occurring, at least seasonally, in the survey area and are thus are expected to be potentially be taken by the proposed activities. For the majority of species potentially present in the specific geographic region, NMFS has designated only a single generic stock (e.g., “western North Atlantic”) for management purposes. This includes the “Canadian east coast” stock of minke whales, which includes all minke whales found in U.S. waters. For humpback and sei whales, NMFS defines stocks on the basis of feeding locations, i.e., Gulf of Maine and Nova Scotia, respectively. However, our reference to humpback whales and sei whales in this document refers to any individuals of the species that are found in the specific geographic region.

The North Atlantic right whale ranges from the calving grounds in the southeastern United States to feeding grounds in New England waters and into Canadian waters (Waring et al., 2016). Surveys have demonstrated the existence of seven areas where North Atlantic right whales congregate seasonally, including Georges Bank, Cape Cod, and Massachusetts Bay (Waring et al., 2016). In the late fall months (e.g., October), right whales generally disappear from the feeding grounds in the North Atlantic and move south to their breeding grounds. The proposed survey area is within the North Atlantic right whale migratory corridor. During the proposed survey (i.e., March through August) right whales may be migrating through the proposed survey area and the surrounding waters.

The western North Atlantic population demonstrated overall growth of 2.8 percent per year between 1990 to 2010, despite a decline in 1993 and no growth between 1997 and 2000 (Pace et al. 2017). However, since 2010 the population has been in decline, with a 99.99 percent probability of a decline of just under 1 percent per year (Pace et al. 2017). Between 1990 and 2015, calving rates varied substantially, with low calving rates coinciding with all three periods of decline or no growth (Pace et al. 2017). On average, North Atlantic right whale calving rates are estimated to be roughly half that of southern right whales (Eubalaena australis) (Pace et al. 2017), which are increasing in abundance (NMFS 2015).

The current abundance estimate for this stock is 458 individuals (Hayes et al., 2018). Data indicates that the number of adult females fell from 200 in 2010 to 186 in 2015 while males fell from 283 to 272 in the same timeframe (Pace et al., 2017). In addition, elevated North Atlantic right whale mortalities have occurred since June 7, 2017. A total of 17 confirmed dead stranded whales (12 in Canada; 5 in the United States), with an additional 5 live whale entanglements in Canada, have been documented to date. This event has been declared an Unusual Mortality Event (UME). More information is available online at: http://www.nmfs.noaa.gov/pr/health/mmume/2017northatlanticrightwhaleume.html.

Humpback whales are found worldwide in all oceans. The humpback whale population within the North Atlantic has been estimated to include approximately 11,570 individuals (Waring et al., 2016). Humpbacks occur off southern New England in all four seasons, with peak abundance in spring and summer. In winter, humpback whales from waters off New England, Canada, Greenland, Iceland, and Norway migrate to mate and calve primarily in the West Indies (including the Antilles, the Dominican Republic, the Virgin Islands and Puerto Rico), where spatial and genetic mixing among these groups occurs (Waring et al., 2015). While migrating, humpback whales utilize the mid-Atlantic as a migration pathway between calving/mating grounds to the south and feeding grounds in the north (Waring et al. 2007).

Since January 2016, elevated humpback whale mortalities have occurred along the Atlantic coast from Maine through North Carolina. Partial or full necropsy examinations have been conducted on approximately half of the 62 known cases. A portion of the whales have shown evidence of pre-mortem vessel strike; however, this finding is not consistent across all of the whales examined so more research is needed. NOAA is consulting with researchers that are conducting studies on the humpback whale populations, and these efforts may provide information on changes in whale distribution and habitat use that could provide additional insight into how these vessel interactions occurred. Three previous UMEs involving humpback whales have occurred since 2000, in 2003, 2005, and 2006. More information is available at www.nmfs.noaa.gov/pr/health/mmume/2017humpbackatlanticume.html.

Fin whales are common in waters of the U.S. Atlantic Exclusive Economic Zone (EEZ), principally from Cape Hatteras northward (Waring et al., 2016). Fin whales are present north of 35-degree latitude in every season and are broadly distributed throughout the western North Atlantic for most of the year (Waring et al., 2016). Fin whales are found in small groups of up to 5 individuals (Brueggeman et al., 1987). The current abundance estimate for the western North Atlantic stock of fin whales is 1,618 individuals (Hayes et al., 2017). The main threats to fin whales are fishery interactions and vessel collisions (Waring et al., 2016).

Minke whales can be found in temperate, tropical, and high-latitude waters. The Canadian East Coast stock can be found in the area from the western half of the Davis Strait (45° W) to the Gulf of Mexico (Waring et al., 2016). This species generally occupies waters less than 100 m deep on the continental shelf. There appears to be a strong seasonal component to minke whale distribution in which spring to fall are times of relatively widespread and common occurrence, and when the whales are most abundant in New England waters, while during winter the species appears to be largely absent (Waring et al., 2016). The main threats to this stock are interactions with fisheries, strandings, and vessel collisions.

The distribution of the sperm whale in the U.S. EEZ occurs on the continental shelf edge, over the continental slope, and into mid-ocean regions (Waring et al., 2014). The basic social unit of the sperm whale appears to be the mixed school of adult females plus their calves and some juveniles of both sexes, normally numbering 20-40 animals in all. There is evidence that some social bonds persist for many years (Christal et al., 1998). This species forms stable social groups, site fidelity, and latitudinal range limitations in groups of females and juveniles (Whitehead, 2002). In summer, the distribution of sperm whales includes the area east and north of Georges Bank and into the Northeast Channel region, as well as the continental shelf (inshore of the 100-m isobath) south of New England. In the fall, sperm whale occurrence south of New England on the continental shelf is at its highest level, and there remains a continental shelf edge occurrence in the mid-Atlantic bight. In winter, sperm whales are concentrated east and northeast of Cape Hatteras. The current abundance estimate for this stock is 2,288 (Hayes et al., 2017).

White-sided dolphins are found in temperate and sub-polar waters of the North Atlantic, primarily in continental shelf waters to the 100-m depth contour from central West Greenland to North Carolina (Waring et al., 2016). There are three stock units: Gulf of Maine, Gulf of St. Lawrence, and Labrador Sea stocks (Palka et al., 1997). The Gulf of Maine population of white-sided dolphins is most common in continental shelf waters from Hudson Canyon (approximately 39° N) to Georges Bank, and in the Gulf of Maine and lower Bay of Fundy. Sighting data indicate seasonal shifts in distribution (Northridge et al., 1997). During January to May, low numbers of white-sided dolphins are found from Georges Bank to Jeffreys Ledge (off New Hampshire), with even lower numbers south of Georges Bank, as documented by a few strandings collected on beaches of Virginia to South Carolina. From June through September, large numbers of white-sided dolphins are found from Georges Bank to the lower Bay of Fundy. From October to December, white-sided dolphins occur at intermediate densities from southern Georges Bank to southern Gulf of Maine (Payne and Heinemann 1990). Sightings south of Georges Bank, particularly around Hudson Canyon, occur year round but at low densities. The current abundance estimate for this stock is 48,819 (Hayes et al., 2017). The main threat to this species is interactions with fisheries.

The short-beaked common dolphin is found worldwide in temperate to subtropical seas. In the North Atlantic, short-beaked common dolphins are commonly found over the continental shelf between the 100-m and 2,000-m isobaths and over prominent underwater topography and east to the mid-Atlantic Ridge (Waring et al., 2016). Only the western North Atlantic stock may be present in the Lease Area. The current abundance estimate for this stock is 70,184 animals (Hayes et al., 2017). The main threat to this species is interactions with fisheries.

There are two distinct bottlenose dolphin morphotypes: The coastal and offshore forms in the western North Atlantic (Waring et al., 2016). The offshore form is distributed primarily along the outer continental shelf and continental slope in the Northwest Atlantic Ocean from Georges Bank to the Florida Keys and is the only type that may be present in the survey area as the survey area is north of the northern extent of the range of the Western North Atlantic Northern Migratory Coastal Stock. The current abundance estimate for the western north Atlantic stock is 77,532 (Hayes et al., 2017). The main threat to this species is interactions with fisheries.

In the Lease Area, only the Gulf of Maine/Bay of Fundy stock may be present. This stock is found in U.S. and Canadian Atlantic waters and is concentrated in the northern Gulf of Maine and southern Bay of Fundy region, generally in waters less than 150 m deep (Waring et al., 2016). They are seen from the coastline to deep waters (>1800 m; Westgate et al. 1998), although the majority of the population is found over the continental shelf (Waring et al., 2016). Average group size for this stock in the Bay of Fundy is approximately four individuals (Palka 2007). The current abundance estimate for this stock is 79,883 (Hayes et al., 2017). The main threat to this species is interactions with fisheries, with documented take in the U.S. northeast sink gillnet, mid-Atlantic gillnet, and northeast bottom trawl fisheries and in the Canadian herring weir fisheries (Waring et al., 2016).

The harbor seal is found in all nearshore waters of the North Atlantic and North Pacific Oceans and adjoining seas above about 30° N (Burns, 2009). In the western North Atlantic, they are distributed from the eastern Canadian Arctic and Greenland south to southern New England and New York, and occasionally to the Carolinas (Waring et al., 2016). Haulout and pupping sites are located off Manomet, MA and the Isles of Shoals, ME, but generally do not occur in areas in southern New England (Waring et al., 2016). The current abundance estimate for this stock is 75,834 (Hayes et al., 2017). The main threat to this species is interactions with fisheries.

There are three major populations of gray seals found in the world; eastern Canada (western North Atlantic stock), northwestern Europe and the Baltic Sea. The gray seals that occur in the Project Area belong to the western North Atlantic stock, which ranges from New Jersey to Labrador. Current population trends show that gray seal abundance is likely increasing in the U.S. Atlantic EEZ (Waring et al., 2016). Although the rate of increase is unknown, surveys conducted since their arrival in the 1980s indicate a steady increase in abundance in both Maine and Massachusetts (Waring et al., 2016). It is believed that recolonization by Canadian gray seals is the source of the U.S. population (Waring et al., 2016).

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. Current data indicate that 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) recommended that marine mammals be divided into functional hearing groups based on directly measured or estimated hearing ranges on the basis of available behavioral response data, audiograms derived using auditory evoked potential techniques, anatomical modeling, and other data. Note that no direct measurements of hearing ability have been successfully completed for mysticetes (i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described generalized hearing ranges for these marine mammal hearing groups. Generalized hearing ranges were chosen based on the approximately 65 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. The functional groups and the associated frequencies are indicated below (note that these frequency ranges correspond to the range for the composite group, with the entire range not necessarily reflecting the capabilities of every species within that group):

• Low-frequency cetaceans (mysticetes): generalized hearing is estimated to occur between approximately 7 Hertz (Hz) and 35 kilohertz (kHz);

• Mid-frequency cetaceans (larger toothed whales, beaked whales, and most delphinids): generalized hearing is estimated to occur between approximately 150 Hz and 160 kHz;

• High-frequency cetaceans (porpoises, river dolphins, and members of the genera Kogia and Cephalorhynchus; including two members of the genus Lagenorhynchus, on the basis of recent echolocation data and genetic data): generalized hearing is estimated to occur between approximately 275 Hz and 160 kHz.

• Pinnipeds in water; Phocidae (true seals): generalized hearing is estimated to occur between approximately 50 Hz to 86 kH;

The pinniped functional hearing group was modified from Southall et al. (2007) on the basis of data indicating that phocid species have consistently demonstrated an extended frequency range of hearing compared to otariids, especially in the higher frequency range (Hemilä et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 2013).

For more detail concerning these groups and associated frequency ranges, please see NMFS (2016) for a review of available information. Eleven marine mammal species (nine cetacean and two pinniped (both phocid) species) have the reasonable potential to co-occur with the proposed survey activities. Please refer to Table 2. Of the cetacean species that may be present, five are classified as low-frequency cetaceans (i.e., all mysticete species), three are classified as mid-frequency cetaceans (i.e., all delphinid species and the sperm whale), and one is classified as a high-frequency cetacean (i.e., harbor porpoise).

This section includes a summary and discussion of the ways that components of the specified activity may impact marine mammals and their habitat. The “Estimated Take” 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” 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 how those impacts on individuals are likely to impact marine mammal species or stocks.

Sound is a physical phenomenon consisting of minute vibrations that travel through a medium, such as air or water, and is generally characterized by several variables. Frequency describes the sound's pitch and is measured in Hz or kHz, while sound level describes the sound's intensity and is measured in decibels (dB). Sound level increases or decreases exponentially with each dB of change. The logarithmic nature of the scale means that each 10-dB increase is a 10-fold increase in acoustic power (and a 20-dB increase is then a 100-fold increase in power). A 10-fold increase in acoustic power does not mean that the sound is perceived as being 10 times louder, however. Sound levels are compared to a reference sound pressure (micro-Pascal) to identify the medium. For air and water, these reference pressures are “re: 20 micro Pascals (µPa)” and “re: 1 µPa,” respectively. Root mean square (RMS) is the quadratic mean sound pressure over the duration of an impulse. RMS is calculated by squaring all of the sound amplitudes, averaging the squares, and then taking the square root of the average (Urick 1975). 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. 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 rather than by peak pressures.

When sound travels (propagates) from its source, its loudness decreases as the distance traveled by the sound increases. Thus, the loudness of a sound at its source is higher than the loudness of that same sound one km away. Acousticians often refer to the loudness of a sound at its source (typically referenced to one meter from the source) as the source level and the loudness of sound elsewhere as the received level (i.e., typically the receiver). For example, a humpback whale 3 km from a device that has a source level of 230 dB may only be exposed to sound that is 160 dB loud, depending on how the sound travels through water (e.g., spherical spreading (6 dB reduction with doubling of distance) was used in this example). As a result, it is important to understand the difference between source levels and received levels when discussing the loudness of sound in the ocean or its impacts on the marine environment.

As sound travels from a source, its propagation in water is influenced by various physical characteristics, including water temperature, depth, salinity, and surface and bottom properties that cause refraction, reflection, absorption, and scattering of sound waves. Oceans are not homogeneous and the contribution of each of these individual factors is extremely complex and interrelated. The physical characteristics that determine the sound's speed through the water will change with depth, season, geographic location, and with time of day (as a result, in actual active sonar operations, crews will measure oceanic conditions, such as sea water temperature and depth, to calibrate models that determine the path the sonar signal will take as it travels through the ocean and how strong the sound signal will be at a given range along a particular transmission path). As sound travels through the ocean, the intensity associated with the wavefront diminishes, or attenuates. This decrease in intensity is referred to as propagation loss, also commonly called transmission loss.

Geophysical surveys may temporarily impact marine mammals in the area due to elevated in-water sound levels. Marine mammals are continually exposed to many sources of sound. Naturally occurring sounds such as lightning, rain, sub-sea earthquakes, and biological sounds (e.g., snapping shrimp, whale songs) are widespread throughout the world's oceans. Marine mammals produce sounds in various contexts and use sound for various biological functions including, but not limited to: (1) Social interactions; (2) foraging; (3) orientation; and (4) predator detection. Interference with producing or receiving these sounds may result in adverse impacts. Audible distance, or received levels of sound depend on the nature of the sound source, ambient noise conditions, and the sensitivity of the receptor to the sound (Richardson et al., 1995). Type and significance of marine mammal reactions to sound are likely dependent on a variety of factors including, but not limited to, (1) the behavioral state of the animal (e.g., feeding, traveling, etc.); (2) frequency of the sound; (3) distance between the animal and the source; and (4) the level of the sound relative to ambient conditions (Southall et al., 2007).

When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different frequencies of sound. Current data indicate that not all marine mammal species have equal hearing capabilities (Richardson et al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008).

Animals are less sensitive to sounds at the outer edges of their functional hearing range and are more sensitive to a range of frequencies within the middle of their functional hearing range. For mid-frequency cetaceans, functional hearing estimates occur between approximately 150 Hz and 160 kHz with best hearing estimated to occur between approximately 10 to less than 100 kHz (Finneran et al., 2005 and 2009, Natchtigall et al., 2005 and 2008; Yuen et al., 2005; Popov et al., 2011; and Schlundt et al., 2011).

Marine mammals may experience temporary or permanent hearing impairment when exposed to loud sounds. Hearing impairment is classified by temporary threshold shift (TTS) and permanent threshold shift (PTS). PTS is considered auditory injury (Southall et al., 2007) and occurs in a specific frequency range and amount. Irreparable damage to the inner or outer cochlear hair cells may cause PTS; however, other mechanisms are also involved, such as exceeding the elastic limits of certain tissues and membranes in the middle and inner ears and resultant changes in the chemical composition of the inner ear fluids (Southall et al., 2007). There are no empirical data for onset of PTS in any marine mammal; therefore, PTS-onset must be estimated from TTS-onset measurements and from the rate of TTS growth with increasing exposure levels above the level eliciting TTS-onset. PTS is presumed to be likely if the hearing threshold is reduced by ≥40 dB (that is, 40 dB of TTS).

TTS is the mildest form of hearing impairment that can occur during exposure to a loud sound (Kryter 1985). While experiencing TTS, the hearing threshold rises and a sound must be stronger in order to be heard. At least in terrestrial mammals, TTS can last from minutes or hours to (in cases of strong TTS) days, can be limited to a particular frequency range, and can occur to varying degrees (i.e., a loss of a certain number of dBs of sensitivity). For sound exposures at or somewhat above the TTS threshold, hearing sensitivity in both terrestrial and marine mammals recovers rapidly after exposure to the noise ends.

Marine mammal hearing plays a critical role in communication with conspecifics and in interpretation of environmental cues for purposes such as predator avoidance and prey capture. 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. For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that takes place during a time when the animals 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 a time when communication is critical for successful mother/calf interactions could have more serious impacts if it were in the same frequency band as the necessary vocalizations and of a severity that it impeded communication. The fact that animals exposed to levels and durations of sound that would be expected to result in this physiological response would also be expected to have behavioral responses of a comparatively more severe or sustained nature is also notable and potentially of more importance than the simple existence of a TTS.

Currently, TTS data only exist for four species of cetaceans (bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor porpoise, and Yangtze finless porpoise (Neophocaena phocaenoides)) and three species of pinnipeds (northern elephant seal (Mirounga angustirostris), harbor seal, and California sea lion (Zalophus californianus)) exposed to a limited number of sound sources (i.e., mostly tones and octave-band noise) in laboratory settings (e.g., Finneran et al., 2002 and 2010; Nachtigall et al., 2004; Kastak et al., 2005; Lucke et al., 2009; Mooney et al., 2009; Popov et al., 2011; Finneran and Schlundt, 2010). In general, harbor seals (Kastak et al., 2005; Kastelein et al., 2012a) and harbor porpoises (Lucke et al., 2009; Kastelein et al., 2012b) have a lower TTS onset than other measured pinniped or cetacean species. However, even for these animals, which are better able to hear higher frequencies and may be more sensitive to higher frequencies, exposures on the order of approximately 170 dB rms or higher for brief transient signals are likely required for even temporary (recoverable) changes in hearing sensitivity that would likely not be categorized as physiologically damaging (Lucke et al., 2009). Additionally, the existing marine mammal TTS data come from a limited number of individuals within these species. There are no data available on noise-induced hearing loss for mysticetes. For summaries of data on TTS in marine mammals or for further discussion of TTS onset thresholds, please see Finneran (2016).

Scientific literature highlights the inherent complexity of predicting TTS onset in marine mammals, as well as the importance of considering exposure duration when assessing potential impacts (Mooney et al., 2009a, 2009b; Kastak et al., 2007). Generally, with sound exposures of equal energy, quieter sounds (lower sound pressure levels (SPL)) of longer duration were found to induce TTS onset more than louder sounds (higher SPL) of shorter duration (more similar to sub-bottom profilers). For intermittent sounds, less threshold shift will occur than from a continuous exposure with the same energy (some recovery will occur between intermittent exposures) (Kryter et al., 1966; Ward 1997). For sound exposures at or somewhat above the TTS-onset threshold, hearing sensitivity recovers rapidly after exposure to the sound ends; intermittent exposures recover faster in comparison with continuous exposures of the same duration (Finneran et al., 2010). NMFS considers TTS as Level B harassment that is mediated by physiological effects on the auditory system.

Animals in the Lease Area during the HRG survey are unlikely to incur TTS hearing impairment due to the characteristics of the sound sources, which include low source levels (208 to 221 dB re 1 µPa-m) and generally very short pulses and duration of the sound. Even for high-frequency cetacean species (e.g., harbor porpoises), which may have increased sensitivity to TTS (Lucke et al., 2009; Kastelein et al., 2012b), individuals would have to make a very close approach and also remain very close to vessels operating these sources in order to receive multiple exposures at relatively high levels, as would be necessary to cause TTS. Intermittent exposures—as would occur due to the brief, transient signals produced by these sources—require a higher cumulative SEL to induce TTS than would continuous exposures of the same duration (i.e., intermittent exposure results in lower levels of TTS) (Mooney et al., 2009a; Finneran et al., 2010). Moreover, most marine mammals would more likely avoid a loud sound source rather than swim in such close proximity as to result in TTS. Kremser et al. (2005) noted that the probability of a cetacean swimming through the area of exposure when a sub-bottom profiler emits a pulse is small—because if the animal was in the area, it would have to pass the transducer at close range in order to be subjected to sound levels that could cause TTS and would likely exhibit avoidance behavior to the area near the transducer rather than swim through at such a close range. Further, the restricted beam shape of the sub-bottom profiler and other HRG survey equipment makes it unlikely that an animal would be exposed more than briefly during the passage of the vessel. Boebel et al. (2005) concluded similarly for single and multibeam echosounders and, more recently, Lurton (2016) conducted a modeling exercise and concluded similarly that likely potential for acoustic injury from these types of systems is negligible but that behavioral response cannot be ruled out. Animals may avoid the area around the survey vessels, thereby reducing exposure. Any disturbance to marine mammals is likely to be in the form of temporary avoidance or alteration of opportunistic foraging behavior near the survey location.

Masking is the obscuring of sounds of interest to an animal by other sounds, typically at similar frequencies. Marine mammals are highly dependent on sound, and their ability to recognize sound signals amid other sound is important in communication and detection of both predators and prey (Tyack 2000). Background ambient sound may interfere with or mask the ability of an animal to detect a sound signal even when that signal is above its absolute hearing threshold. Even in the absence of anthropogenic sound, the marine environment is often loud. Natural ambient sound includes contributions from wind, waves, precipitation, other animals, and (at frequencies above 30 kHz) thermal sound resulting from molecular agitation (Richardson et al., 1995).

Background sound may also include anthropogenic sound, and masking of natural sounds can result when human activities produce high levels of background sound. Conversely, if the background level of underwater sound is high (e.g., on a day with strong wind and high waves), an anthropogenic sound source would not be detectable as far away as would be possible under quieter conditions and would itself be masked. Ambient sound is highly variable on continental shelves (Myrberg 1978; Desharnais et al., 1999). This results in a high degree of variability in the range at which marine mammals can detect anthropogenic sounds.

Although masking is a phenomenon which may occur naturally, the introduction of loud anthropogenic sounds into the marine environment at frequencies important to marine mammals increases the severity and frequency of occurrence of masking. For example, if a baleen whale is exposed to continuous low-frequency sound from an industrial source, this would reduce the size of the area around that whale within which it can hear the calls of another whale. The components of background noise that are similar in frequency to the signal in question primarily determine the degree of masking of that signal. In general, little is known about the degree to which marine mammals rely upon detection of sounds from conspecifics, predators, prey, or other natural sources. In the absence of specific information about the importance of detecting these natural sounds, it is not possible to predict the impact of masking on marine mammals (Richardson et al., 1995). In general, masking effects are expected to be less severe when sounds are transient than when they are continuous. Masking is typically of greater concern for those marine mammals that utilize low-frequency communications, such as baleen whales, because of how far low-frequency sounds propagate.

Marine mammal communications would not likely be masked appreciably by the sub-bottom profiler signals given the directionality of the signal and the brief period when an individual mammal is likely to be within its beam.

Classic stress responses begin when an animal's central nervous system perceives a potential threat to its homeostasis. That perception triggers stress responses regardless of whether a stimulus actually threatens the animal; the mere perception of a threat is sufficient to trigger a stress response (Moberg 2000; Seyle 1950). Once an animal's central nervous system perceives a threat, it mounts a biological response or defense that consists of a combination of the four general biological defense responses: behavioral responses, autonomic nervous system responses, neuroendocrine responses, or immune responses.

In the case of many stressors, an animal's first and sometimes most economical (in terms of biotic costs) response is behavioral avoidance of the potential stressor or avoidance of continued exposure to a stressor. An animal's second line of defense to stressors involves the sympathetic part of the autonomic nervous system and the classical “fight or flight” response which includes the cardiovascular system, the gastrointestinal system, the exocrine glands, and the adrenal medulla to produce changes in heart rate, blood pressure, and gastrointestinal activity that humans commonly associate with “stress.” These responses have a relatively short duration and may or may not have significant long-term effect on an animal's welfare.

An animal's third line of defense to stressors involves its neuroendocrine systems; the system that has received the most study has been the hypothalamus-pituitary-adrenal system (also known as the HPA axis in mammals). Unlike stress responses associated with the autonomic nervous system, virtually all neuro-endocrine 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 (Moberg 1987; Rivier 1995), altered metabolism (Elasser et al., 2000), reduced immune competence (Blecha 2000), and behavioral disturbance. Increases in the circulation of glucocorticosteroids (cortisol, corticosterone, and aldosterone in marine mammals; see Romano et al., 2004) have been equated with stress for many years.

The primary distinction between stress (which is adaptive and does not normally place an animal at risk) and distress is the biotic 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 a risk to the animal's welfare. 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 biotic function, which impairs those functions that experience the diversion. For example, when mounting a stress response diverts energy away from growth in young animals, those animals may experience stunted growth. When mounting a stress response diverts energy from a fetus, an animal's reproductive success and its fitness will suffer. In these cases, the animals will have entered a pre-pathological or pathological state which is called “distress” (Seyle 1950) or “allostatic loading” (McEwen and Wingfield 2003). This pathological state will last until the animal replenishes its biotic reserves sufficient to restore normal function. Note that these examples involved a long-term (days or weeks) stress response exposure to stimuli.

Relationships between these physiological mechanisms, animal behavior, and the costs of stress responses have also been documented fairly well through controlled experiments; because this physiology exists in every vertebrate that has been studied, it is not surprising that stress responses and their costs have been documented in both laboratory and free-living animals (for examples see, Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer, 2000). Information has also been collected on the physiological responses of marine mammals to exposure to anthropogenic sounds (Fair and Becker 2000; Romano et al., 2002). 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.

Studies of other marine animals and terrestrial animals would also lead us to expect some marine mammals to experience physiological stress responses and, perhaps, physiological responses that would be classified as “distress” upon exposure to high frequency, mid-frequency and low-frequency sounds. For example, Jansen (1998) reported on the relationship between acoustic exposures and physiological responses that are indicative of stress responses in humans (for example, elevated respiration and increased heart rates). Jones (1998) reported on reductions in human performance when faced with acute, repetitive exposures to acoustic disturbance. Trimper et al. (1998) reported on the physiological stress responses of osprey to low-level aircraft noise while Krausman et al. (2004) reported on the auditory and physiology stress responses of endangered Sonoran pronghorn to military overflights. Smith et al. (2004a, 2004b), for example, identified noise-induced physiological transient stress responses in hearing-specialist fish (i.e., goldfish) that accompanied short- and long-term hearing losses. Welch and Welch (1970) reported physiological and behavioral stress responses that accompanied damage to the inner ears of fish and several mammals.

Hearing is one of the primary senses marine mammals use to gather information about their environment and to communicate with conspecifics. Although empirical information on the relationship between sensory impairment (TTS, PTS, and acoustic masking) on marine mammals remains limited, it seems reasonable to assume that reducing an animal's ability to gather information about its environment and to communicate with other members of its species would be stressful for animals that use hearing as their primary sensory mechanism. Therefore, we assume that acoustic exposures sufficient to trigger onset PTS or TTS would be accompanied by physiological stress responses because terrestrial animals exhibit those responses under similar conditions (NRC 2003). More importantly, marine mammals might experience stress responses at received levels lower than those necessary to trigger onset TTS. Based on empirical studies of the time required to recover from stress responses (Moberg 2000), we also assume that stress responses are likely to persist beyond the time interval required for animals to recover from TTS and might result in pathological and pre-pathological states that would be as significant as behavioral responses to TTS.

In general, there are few data on the potential for strong, anthropogenic underwater sounds to cause non-auditory physical effects in marine mammals. The available data do not allow identification of a specific exposure level above which non-auditory effects can be expected (Southall et al., 2007). There is no definitive evidence that any of these effects occur even for marine mammals in close proximity to an anthropogenic sound source. In addition, marine mammals that show behavioral avoidance of survey vessels and related sound sources are unlikely to incur non-auditory impairment or other physical effects. NMFS does not expect that the generally short-term, intermittent, and transitory HRG and geotechnical activities would create conditions of long-term, continuous noise and chronic acoustic exposure leading to long-term physiological stress responses in marine mammals.

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 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., 2003; Southall et al., 2007; Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not only among individuals but also within an individual, depending on previous experience with a sound source, context, and numerous other factors (Ellison et al., 2012), and can vary depending on characteristics associated with the sound source (e.g., whether it is moving or stationary, number of sources, distance from the source). Please see Appendices B-C of Southall et al. (2007) for a review 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., 2003). 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, 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; NRC 2003; Wartzok et al., 2003). Controlled experiments with captive marine mammals have shown pronounced behavioral reactions, including avoidance of loud sound sources (Ridgway et al., 1997; Finneran et al., 2003). Observed responses of wild marine mammals to loud, pulsed sound sources (typically seismic airguns or acoustic harassment devices) have been varied but often consist of avoidance behavior or other behavioral changes suggesting discomfort (Morton and Symonds, 2002; see also Richardson et al., 1995; 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. 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,b). 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. As for other types of behavioral response, the frequency, duration, and temporal pattern of signal presentation, as well as differences in species sensitivity, are likely contributing factors to differences in response in any given circumstance (e.g., Croll et al., 2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 2007). A determination of whether foraging disruptions incur fitness consequences would require information on or estimates of the energetic requirements of the affected individuals and the relationship between prey availability, foraging effort and success, and the life history stage of the animal.

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, 2005b, 2006; Gailey et al., 2007).

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; Foote et al., 2004), while right whales 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., 2007b). In some cases, animals may cease sound production during production of aversive signals (Bowles et al., 1994).

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). Avoidance may be short-term, with animals returning to the area once the noise has ceased (e.g., Bowles et al., 1994; Goold 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). Longer-term displacement is possible, however, which may lead to changes in abundance or distribution patterns of the affected species in the affected region if habituation to the presence of the sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al., 2006).

A flight response is a dramatic change in normal movement to a directed and rapid movement away from the perceived location of a sound source. The flight response differs from other avoidance responses in the intensity of the response (e.g., directed movement, rate of travel). Relatively little information on flight responses of marine mammals to anthropogenic signals exist, although observations of flight responses to the presence of predators have occurred (Connor and Heithaus, 1996). 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 (Evans and England, 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 fish 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 five-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 one day and not recurring on subsequent days is not considered particularly severe unless it could directly affect reproduction or survival (Southall et al., 2007). Note that there is a difference between multi-day substantive 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.

Marine mammals are likely to avoid the HRG survey activity, especially the naturally shy harbor porpoise, while the harbor seals might be attracted to them out of curiosity. However, because the sub-bottom profilers and other HRG survey equipment operate from a moving vessel, and the maximum radius to the Level B harassment threshold is relatively small, the area and time that this equipment would be affecting a given location is very small. Further, once an area has been surveyed, it is not likely that it will be surveyed again, thereby reducing the likelihood of repeated HRG-related impacts within the survey area.

We have also considered the potential for severe behavioral responses such as stranding and associated indirect injury or mortality from Statoil's use of HRG survey equipment, on the basis of a 2008 mass stranding of approximately 100 melon-headed whales in a Madagascar lagoon system. An investigation of the event indicated that use of a high-frequency mapping system (12-kHz multibeam echosounder) was the most plausible and likely initial behavioral trigger of the event, while providing the caveat that there is no unequivocal and easily identifiable single cause (Southall et al., 2013). The investigatory panel's conclusion was based on (1) very close temporal and spatial association and directed movement of the survey with the stranding event; (2) the unusual nature of such an event coupled with previously documented apparent behavioral sensitivity of the species to other sound types (Southall et al., 2006; Brownell et al., 2009); and (3) the fact that all other possible factors considered were determined to be unlikely causes. Specifically, regarding survey patterns prior to the event and in relation to bathymetry, the vessel transited in a north-south direction on the shelf break parallel to the shore, ensonifying large areas of deep-water habitat prior to operating intermittently in a concentrated area offshore from the stranding site; this may have trapped the animals between the sound source and the shore, thus driving them towards the lagoon system. The investigatory panel systematically excluded or deemed highly unlikely nearly all potential reasons for these animals leaving their typical pelagic habitat for an area extremely atypical for the species (i.e., a shallow lagoon system). Notably, this was the first time that such a system has been associated with a stranding event. The panel also noted several site- and situation-specific secondary factors that may have contributed to the avoidance responses that led to the eventual entrapment and mortality of the whales. Specifically, shoreward-directed surface currents and elevated chlorophyll levels in the area preceding the event may have played a role (Southall et al., 2013). The report also notes that prior use of a similar system in the general area may have sensitized the animals and also concluded that, for odontocete cetaceans that hear well in higher frequency ranges where ambient noise is typically quite low, high-power active sonars operating in this range may be more easily audible and have potential effects over larger areas than low frequency systems that have more typically been considered in terms of anthropogenic noise impacts. It is, however, important to note that the relatively lower output frequency, higher output power, and complex nature of the system implicated in this event, in context of the other factors noted here, likely produced a fairly unusual set of circumstances that indicate that such events would likely remain rare and are not necessarily relevant to use of lower-power, higher-frequency systems more commonly used for HRG survey applications. The risk of similar events recurring may be very low, given the extensive use of active acoustic systems used for scientific and navigational purposes worldwide on a daily basis and the lack of direct evidence of such responses previously reported.

Numerous studies have shown that underwater sounds from industrial activities are often readily detectable by marine mammals in the water at distances of many km. However, other studies have shown that marine mammals at distances more than a few km away often show no apparent response to industrial activities of various types (Miller et al., 2005). This is often true even in cases when the sounds must be readily audible to the animals based on measured received levels and the hearing sensitivity of that mammal group. Although various baleen whales, toothed whales, and (less frequently) pinnipeds have been shown to react behaviorally to underwater sound from sources such as airgun pulses or vessels under some conditions, at other times, mammals of all three types have shown no overt reactions (e.g., Malme et al., 1986; Richardson et al., 1995; Madsen and Mohl 2000; Croll et al., 2001; Jacobs and Terhune 2002; Madsen et al., 2002; Miller et al., 2005). In general, pinnipeds seem to be more tolerant of exposure to some types of underwater sound than are baleen whales. Richardson et al. (1995) found that vessel sound does not seem to affect pinnipeds that are already in the water. Richardson et al. (1995) went on to explain that seals on haul-outs sometimes respond strongly to the presence of vessels and at other times appear to show considerable tolerance of vessels, and Brueggeman et al. (1992) observed ringed seals (Pusa hispida) hauled out on ice pans displaying short-term escape reactions when a ship approached within 0.16-0.31 miles (0.25-0.5 km). Due to the relatively high vessel traffic in the Lease Area it is possible that marine mammals are habituated to noise (e.g., DP thrusters) from project vessels in the area.

Ship strikes of marine mammals can cause major wounds, which may lead to the death of the animal. An animal at the surface could be struck directly by a vessel, a surfacing animal could hit the bottom of a vessel, or a vessel's propeller could injure an animal just below the surface. The severity of injuries typically depends on the size and speed of the vessel (Knowlton and Kraus 2001; Laist et al., 2001; Vanderlaan and Taggart 2007).

The most vulnerable marine mammals are those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives (e.g., the sperm whale). In addition, some baleen whales, such as the North Atlantic right whale, seem generally unresponsive to vessel sound, making them more susceptible to vessel collisions (Nowacek et al., 2004). These species are primarily large, slow moving whales. Smaller marine mammals (e.g., bottlenose dolphin) move quickly through the water column and are often seen riding the bow wave of large ships. Marine mammal responses to vessels may include avoidance and changes in dive pattern (NRC 2003).

An examination of all known ship strikes from all shipping sources (civilian and military) indicates vessel speed is a principal factor in whether a vessel strike results in death (Knowlton and Kraus 2001; Laist et al., 2001; Jensen and Silber 2003; Vanderlaan and Taggart 2007). In assessing records with known vessel speeds, Laist et al. (2001) found a direct relationship between the occurrence of a whale strike and the speed of the vessel involved in the collision. The authors concluded that most deaths occurred when a vessel was traveling in excess of 24.1 km/h (14.9 mph; 13 knots (kn)). Given the slow vessel speeds and predictable course necessary for data acquisition, ship strike is unlikely to occur during the geophysical and geotechnical surveys. Marine mammals would be able to easily avoid the survey vessel due to the slow vessel speed. Further, Statoil would implement measures (e.g., protected species monitoring, vessel speed restrictions and separation distances; see Proposed Mitigation Measures) set forth in the BOEM lease to reduce the risk of a vessel strike to marine mammal species in the survey area.

There are no feeding areas, rookeries or mating grounds known to be biologically important to marine mammals within the proposed project area. The area is part of an important migratory area for North Atlantic right whales; this important migratory area is comprised of the waters of the continental shelf offshore the East Coast of the U.S. and extends from Florida through Massachusetts. Given the limited spatial extent of the proposed survey and the large spatial extent of the migratory area, we do not expect North Atlantic right whale migration to be negatively impacted by the proposed survey. There is no designated critical habitat for any ESA-listed marine mammals in the proposed survey area. NMFS' regulations at 50 CFR part 224.105 designated the nearshore waters of the Mid-Atlantic Bight as the Mid-Atlantic U.S. Seasonal Management Area (SMA) for right whales in 2008. Mandatory vessel speed restrictions (less than 10 kn) are in place in that SMA from November 1 through April 30 to reduce the threat of collisions between ships and right whales around their migratory route and calving grounds.

Bottom disturbance associated with the HRG survey activities may include grab sampling to validate the seabed classification obtained from the multibeam echosounder/sidescan sonar data. This will typically be accomplished using a Mini-Harmon Grab with 0.1 m2 sample area or the slightly larger Harmon Grab with a 0.2 m2 sample area. The HRG survey equipment will not contact the seafloor and does not represent a source of pollution. We are not aware of any available literature on impacts to marine mammal prey from HRG survey equipment. However, as the HRG survey equipment introduces noise to the marine environment, there is the potential for it to result in avoidance of the area around the HRG survey activities on the part of marine mammal prey. Any avoidance of the area on the part of marine mammal prey would be expected to be short term and temporary.

Because of the temporary nature of the disturbance, the availability of similar habitat and resources (e.g., prey species) in the surrounding area, and the lack of important or unique marine mammal habitat, the impacts to marine mammals and the food sources that they utilize are not expected to cause significant or long-term consequences for individual marine mammals or their populations. Impacts on marine mammal habitat from the proposed activities will be temporary, insignificant, and discountable.

This section provides an estimate of the number of incidental takes proposed for authorization through this IHA, which will inform both NMFS' consideration of “small numbers” and the negligible impact determination.

Harassment is the only type of take expected to result from these activities. Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

Authorized takes would be by Level B harassment, as use of the HRG equipment has the potential to result in disruption of behavioral patterns for individual marine mammals. NMFS has determined take by Level A harassment is not an expected outcome of the proposed activity and thus we do not propose to authorize the take of any marine mammals by Level A harassment. This is discussed in greater detail below. As described previously, no mortality or serious injury is anticipated or proposed to be authorized for this activity. Below we describe how the take is estimated for this project.

Described in the most basic way, we estimate take by considering: (1) Acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be behaviorally harassed or incur some degree of permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and, (4) and the number of days of activities. Below, we describe these components in more detail and present the proposed take estimate.

NMFS uses acoustic thresholds that identify the received level of underwater sound above which exposed marine mammals would be reasonably expected to be behaviorally harassed (equated to Level B harassment) or to incur PTS of some degree (equated to Level A harassment).

Level B harassment—Though significantly driven by received level, the onset of behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the sound source (e.g., frequency, predictability, duty cycle); the environment (e.g., bathymetry); and the receiving animals (hearing, motivation, experience, demography, behavioral context); therefore can be difficult to predict (Southall et al., 2007, Ellison et al., 2011). NMFS uses a generalized acoustic threshold based on received level to estimate the onset of Level B (behavioral) harassment. NMFS predicts that marine mammals may be behaviorally harassed when exposed to underwater anthropogenic noise above received levels 160 dB re 1 μPa (rms) for non-explosive impulsive (e.g., seismic HRG equipment) or intermittent (e.g., scientific sonar) sources. Statoil's proposed activity includes the use of impulsive sources. Therefore, the 160 dB re 1 μPa (rms) criteria is applicable for analysis of Level B harassment.

Level A harassment—NMFS' Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2016) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). The Technical Guidance identifies the received levels, or thresholds, above which individual marine mammals are predicted to experience changes in their hearing sensitivity for all underwater anthropogenic sound sources, reflects the best available science, and better predicts the potential for auditory injury than does NMFS' historical criteria.

These thresholds were developed by compiling and synthesizing the best available science and soliciting input multiple times from both the public and peer reviewers to inform the final product, and are provided in Table 3 below. The references, analysis, and methodology used in the development of the thresholds are described in NMFS 2016 Technical Guidance, which may be accessed at: www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. As described above, Statoil's proposed activity includes the use of intermittent and impulsive sources

Here, we describe operational and environmental parameters of the activity that will feed into estimating the area ensonified above the acoustic thresholds.

The proposed survey would entail the use of HRG survey equipment. The distance to the isopleth corresponding to the threshold for Level B harassment was calculated for all HRG survey equipment with the potential to result in harassment of marine mammals (i.e., the USBL and the sub-bottom profilers; Table 1) based on source characteristics as described in Crocker and Fratantonio (2016) using the practical transmission loss (TL) equation: TL = 15log10 r. Of the HRG survey equipment planned for use that has the potential to result in harassment of marine mammals, acoustic modeling indicated the Sig ELC 820 Sparker would be expected to produce sound that would propagate the furthest in the water (Table 4); therefore, for the purposes of the take calculation, it was assumed the Sig ELC 820 Sparker would be active during the entirety of the survey. Thus the distance to the isopleth corresponding to the threshold for Level B harassment for the Sig ELC 820 Sparker (1,166 m; Table 4) was used as the basis of the Level B take calculation for all marine mammals.

Predicted distances to Level A harassment isopleths, which vary based on marine mammal functional hearing groups (Table 5), were also calculated by Statoil. The updated acoustic thresholds for impulsive sounds (such as HRG survey equipment) contained in the Technical Guidance (NMFS, 2016) were presented as dual metric acoustic thresholds using both SELcum and peak sound pressure level metrics. As dual metrics, NMFS considers onset of PTS (Level A harassment) to have occurred when either one of the two metrics is exceeded (i.e., metric resulting in the largest isopleth). The SELcum metric considers both level and duration of exposure, as well as auditory weighting functions by marine mammal hearing group. In recognition of the fact that calculating Level A harassment ensonified areas could be more technically challenging to predict due to the duration component and the use of weighting functions in the new SELcum thresholds, NMFS developed an optional User Spreadsheet that includes tools to help predict a simple isopleth that can be used in conjunction with marine mammal density or occurrence to facilitate the estimation of take numbers. Statoil used the NMFS optional User Spreadsheet to calculate distances to Level A harassment isopleths based on SELcum (shown in Appendix A of the IHA application) and used the practical spreading loss model (similar to the method used to calculate Level B isopleths as described above) to calculate distances to Level A harassment isopleths based on peak pressure. Modeled distances to isopleths corresponding to Level A harassment thresholds for the Sig ELC 820 Sparker are shown in Table 5.

In this case, due to the very small estimated distances to Level A harassment thresholds for all marine mammal functional hearing groups, based on both SELcum and peak SPL (Table 5), and in consideration of the proposed mitigation measures, including marine mammal exclusion zones that greatly exceed the largest modeled isopleths to Level A harassment thresholds (see the Proposed Mitigation section for more detail) NMFS has determined that the likelihood of Level A take of marine mammals occurring as a result of the proposed survey is so low as to be discountable.

We note that because of some of the assumptions included in the methods used, isopleths produced may be overestimates to some degree. The acoustic sources proposed for use in Statoil's survey do not radiate sound equally in all directions but were designed instead to focus acoustic energy directly toward the sea floor. Therefore, the acoustic energy produced by these sources is not received equally in all directions around the source but is instead concentrated along some narrower plane depending on the beamwidth of the source. However, the calculated distances to isopleths do not account for this directionality of the sound source and are therefore conservative. For mobile sources, such as the proposed survey, the User Spreadsheet predicts the closest distance at which a stationary animal would not incur PTS if the sound source traveled by the animal in a straight line at a constant speed.

In this section we provide the information about the presence, density, or group dynamics of marine mammals that will inform the take calculations.

The best available scientific information was considered in conducting marine mammal exposure estimates (the basis for estimating take). For cetacean species, densities calculated by Roberts et al. (2016) were used. The density data presented by Roberts et al. (2016) incorporates aerial and shipboard line-transect survey data from NMFS and from other organizations collected over the period 1992-2014. Roberts et al. (2016) modeled density from 8 physiographic and 16 dynamic oceanographic and biological covariates, and controlled for the influence of sea state, group size, availability bias, and perception bias on the probability of making a sighting. In general, NMFS considers the models produced by Roberts et al. (2016) to be the best available source of data regarding cetacean density in the Atlantic Ocean. More information, including the model results and supplementary information for each model, is available online at: seamap.env.duke.edu/models/Duke-EC-GOM-2015/.

For the purposes of the take calculations, density data from Roberts et al. (2016) were mapped within the boundary of the survey area for each survey segment (i.e., the Lease Area survey segment and the cable route area survey segment; See Figure 1 in the IHA application) using a geographic information system. Monthly density data for all cetacean species potentially taken by the proposed survey was available via Roberts et al. (2016). Monthly mean density within the survey area, as provided in Roberts et al. (2016), were averaged by season (i.e., Winter (December, January, February), Spring (March, April, May), Summer (June, July, August), Fall (September, October, November)) to provide seasonal density estimates. For the Lease Area survey segment, the highest average seasonal density as reported by Roberts et al. (2016) was used based on the planned survey dates of March through July. For the cable route area survey segment, the average spring seasonal densities within the maximum survey area were used, given the planned start date and duration of the survey within the cable route area.

Systematic, offshore, at-sea survey data for pinnipeds are more limited than those for cetaceans. The best available information concerning pinniped densities in the proposed survey area is the U.S. Navy's Navy Operating Area (OPAREA) Density Estimates (NODEs) (DoN, 2007). These density models utilized vessel-based and aerial survey data collected by NMFS from 1998-2005 during broad-scale abundance studies. Modeling methodology is detailed in DoN (2007). The NODEs density estimates do not include density data for gray seals. For the purposes of this IHA, gray seal density in the project area was assumed to be the same as harbor seal density. Mid-Atlantic OPAREA Density Estimates (DoN, 2007) as reported for the spring and summer season were used to estimate pinniped densities for the purposes of the take calculations.

Here we describe how the information provided above is brought together to produce a quantitative take estimate.

In order to estimate the number of marine mammals predicted to be exposed to sound levels that would result in harassment, radial distances to predicted isopleths corresponding to harassment thresholds are calculated, as described above. Those distances are then used to calculate the area(s) around the HRG survey equipment predicted to be ensonified to sound levels that exceed harassment thresholds. The area estimated to be ensonified to relevant thresholds in a single day of the survey is then calculated, based on areas predicted to be ensonified around the HRG survey equipment and estimated trackline distance traveled per day by the survey vessel. The estimated daily vessel track line distance was determined using the estimated average speed of the vessel (4 kn) multiplied by 24 (to account for the 24 hour operational period of the survey). Using the maximum distance to the Level B harassment threshold of 1,166 m (Table 4) and estimated daily track line distance of approximately 177.8 km (110.5 mi), it was estimated that an area of 418.9 km2 (161.7 mi2) per day would be ensonified to the Level B harassment threshold (Table 6).

The number of marine mammals expected to be incidentally taken per day is then calculated by estimating the number of each species predicted to occur within the daily ensonified area, using estimated marine mammal densities as described above. In this case, estimated marine mammal density values varied between the Lease Area and cable route corridor survey areas, therefore the estimated number of each species taken per survey day was calculated separately for the Lease Area survey area and cable route corridor survey area. Estimated numbers of each species taken per day are then multiplied by the number of survey days to generate an estimate of the total number of each species expected to be taken over the duration of the survey. In this case, as the estimated number of each species taken per day varied depending on survey area (Lease Area and cable route corridor), the number of each species taken per day in each respective survey area was multiplied by the number of survey days anticipated in each survey area (i.e., 123 survey days in the Lease Area portion of the survey and 19 survey days in the cable route corridor portion of the survey) to get a total number of takes per species in each respective survey area. Total take numbers for each respective survey area (Lease Area and cable route corridor) were then rounded. These numbers were then summed to get a total number of each species expected to be taken over the duration of all surveys (Table 9).

As described above, due to the very small estimated distances to Level A harassment thresholds (based on both SELcum and peak SPL; Table 5), and in consideration of the proposed mitigation measures, the likelihood of the proposed survey resulting in take in the form of Level A harassment is considered so low as to be discountable, therefore we do not propose to authorize take of any marine mammals by Level A harassment. Proposed take numbers are shown in Tables 7, 8 and 9. Take numbers proposed for authorization (Tables 7, 8 and 9) are slightly different than those requested in the IHA application (Table 7 in the IHA application) due to slight differences in take calculation methods.

In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses (latter not applicable for this action). NMFS regulations require applicants for incidental take authorizations to include information about the availability and feasibility (economic and technological) of equipment, methods, and manner of conducting such activity or other means of effecting the least practicable adverse impact upon the affected species or stocks and their habitat (50 CFR 216.104(a)(11)).

In evaluating how mitigation may or may not be appropriate to ensure the least practicable adverse impact on species or stocks and their habitat, as well as subsistence uses where applicable, we carefully consider two primary factors:

(1) The manner in which, and the degree to which, the successful implementation of the measure(s) is expected to reduce impacts to marine mammals, marine mammal species or stocks, and their habitat. This considers the nature of the potential adverse impact being mitigated (likelihood, scope, range). It further considers the likelihood that the measure will be effective if implemented (probability of accomplishing the mitigating result if implemented as planned) the likelihood of effective implementation (probability implemented as planned), and;

(2) The practicability of the measures for applicant implementation, which may consider such things as relative cost and impact on operations.

With NMFS' input during the application process, and as per the BOEM Lease, Statoil is proposing the following mitigation measures during the proposed marine site characterization surveys.

As required in the BOEM lease, marine mammal exclusion zones (EZ) will be established around the HRG survey equipment and monitored by protected species observers (PSO) during HRG surveys as follows:

• 50 m EZ for pinnipeds and delphinids (except harbor porpoises);

• 100 m EZ for large whales including sperm whales and mysticetes (except North Atlantic right whales) and harbor porpoises;

• 500 m EZ for North Atlantic right whales.

In addition, PSOs will visually monitor to the extent of the Level B zone (1,166 m), or as far as possible if the extent of the Level B zone is not fully visible.

Statoil intends to submit a sound source verification report showing sound levels associated with HRG survey equipment. If results of the sound source verification report indicate that actual distances to isopleths corresponding to harassment thresholds are larger than the EZs and/or Level B monitoring zones, NMFS may modify the zone(s) accordingly. If results of source verification indicate that actual distances to isopleths corresponding to harassment thresholds are less than the EZs and/or Level B monitoring zones, Statoil has indicated an intention to request modification of the zone(s), as appropriate. NMFS would review any such request and may modify the zone(s) depending on review of the report on source verification. Any such modification may be superseded by EZs required by BOEM.

As per the BOEM lease, visual and acoustic monitoring of the established exclusion and monitoring zones will be performed by qualified and NMFS-approved PSOs. It will be the responsibility of the Lead PSO on duty to communicate the presence of marine mammals as well as to communicate and enforce the action(s) that are necessary to ensure mitigation and monitoring requirements are implemented as appropriate. PSOs will be equipped with binoculars and have the ability to estimate distances to marine mammals located in proximity to the vessel and/or exclusion zone using range finders. Reticulated binoculars will also be available to PSOs for use as appropriate based on conditions and visibility to support the siting and monitoring of marine species. Digital single-lens reflex camera equipment will be used to record sightings and verify species identification. During surveys conducted at night, night-vision equipment and infrared technology will be available for PSO use, and passive acoustic monitoring (PAM; described below) will be used.

For all HRG survey activities, Statoil would implement a 30-minute pre-clearance period of the relevant EZs prior to the initiation of HRG survey equipment (as required by BOEM). During this period the EZs would be monitored by PSOs, using the appropriate visual technology for a 30-minute period. HRG survey equipment would not be initiated if marine mammals are observed within or approaching the relevant EZs during this pre-clearance period. If a marine mammal were observed within or approaching the relevant EZ during the pre-clearance period, ramp-up would not begin until the animal(s) has been observed exiting the EZ or until an additional time period has elapsed with no further sighting of the animal (15 minutes for small delphinoid cetaceans and pinnipeds and 30 minutes for all other species). This pre-clearance requirement would include small delphinoids that approach the vessel (e.g., bow ride). PSOs would also continue to monitor the zone for 30 minutes after survey equipment is shut down or survey activity has concluded.

As required in the BOEM lease, PAM would be required during HRG surveys conducted at night. In addition, PAM systems would be employed during daylight hours as needed to support system calibration and PSO and PAM team coordination, as well as in support of efforts to evaluate the effectiveness of the various mitigation techniques (i.e., visual observations during day and night, compared to the PAM detections/operations). PAM operators will also be on call as necessary during daytime operations should visual observations become impaired. BOEM's lease stipulations require the use of PAM during nighttime operations. However, these requirements do not require that any mitigation action be taken upon acoustic detection of marine mammals. Given the range of species that could occur in the survey area, the PAM system will consist of an array of hydrophones with both broadband (sampling mid-range frequencies of 2 kHz to 200 kHz) and at least one low-frequency hydrophone (sampling range frequencies of 75 Hz to 30 kHz). The PAM operator would monitor the hydrophone signals in real time both aurally (using headphones) and visually (via the monitor screen displays). PAM operator would communicate detections to the Lead PSO on duty who will ensure the implementation of the appropriate mitigation procedures. A mitigation and monitoring communications flow diagram has been included as Appendix C of the IHA application.

As required in the BOEM lease, where technically feasible, a ramp-up procedure would be used for HRG survey equipment capable of adjusting energy levels at the start or re-start of HRG survey activities. The ramp-up procedure would be used at the beginning of HRG survey activities in order to provide additional protection to marine mammals near the survey area by allowing them to vacate the area prior to the commencement of survey equipment use at full energy. A ramp-up would begin with the power of the smallest acoustic equipment at its lowest practical power output appropriate for the survey. When technically feasible the power would then be gradually turned up and other acoustic sources added in way such that the source level would increase gradually.

As required in the BOEM lease, if a marine mammal is observed within or approaching the relevant EZ (as described above) an immediate shutdown of the survey equipment is required. Subsequent restart of the survey equipment may only occur after the animal(s) has either been observed exiting the relevant EZ or until an additional time period has elapsed with no further sighting of the animal (15 minutes for delphinoid cetaceans and pinnipeds and 30 minutes for all other species). HRG survey equipment may be allowed to continue operating if small delphinids voluntarily approach the vessel (e.g., to bow ride) when HRG survey equipment is operating.

As required in the BOEM lease, if the HRG equipment shuts down for reasons other than mitigation (i.e., mechanical or electronic failure) resulting in the cessation of the survey equipment for a period greater than 20 minutes, a 30 minute pre-clearance period (as described above) would precede the restart of the HRG survey equipment. If the pause is less than less than 20 minutes, the equipment may be restarted as soon as practicable at its full operational level only if visual surveys were continued diligently throughout the silent period and the EZs remained clear of marine mammals during that entire period. If visual surveys were not continued diligently during the pause of 20 minutes or less, a 30-minute pre-clearance period (as described above) would precede the re-start of the HRG survey equipment. Following a shutdown, HRG survey equipment may be restarted following pre-clearance of the zones as described above.

Statoil will ensure that vessel operators and crew maintain a vigilant watch for cetaceans and pinnipeds by slowing down or stopping the vessel to avoid striking marine mammals. Survey vessel crew members responsible for navigation duties will receive site-specific training on marine mammal sighting/reporting and vessel strike avoidance measures. Vessel strike avoidance measures will include, but are not limited to, the following, as required in the BOEM lease, except under circumstances when complying with these requirements would put the safety of the vessel or crew at risk:

• All vessel operators and crew will maintain vigilant watch for cetaceans and pinnipeds, and slow down or stop their vessel to avoid striking these protected species;

• All vessel operators will comply with 10 knot (18.5 km/hr) or less speed restrictions in any SMA per NOAA guidance. This applies to all vessels operating at any time of year;

• All vessel operators will reduce vessel speed to 10 knots (18.5 km/hr) or less when any large whale, any mother/calf pairs, pods, or large assemblages of non-delphinoid cetaceans are observed near (within 100 m [330 ft]) an underway vessel;

• All survey vessels will maintain a separation distance of 500 m (1640 ft) or greater from any sighted North Atlantic right whale;

• If underway, vessels must steer a course away from any sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less until the 500 m (1640 ft) minimum separation distance has been established. If a North Atlantic right whale is sighted in a vessel's path, or within 100 m (330 ft) to an underway vessel, the underway vessel must reduce speed and shift the engine to neutral. Engines will not be engaged until the North Atlantic right whale has moved outside of the vessel's path and beyond 100 m. If stationary, the vessel must not engage engines until the North Atlantic right whale has moved beyond 100 m;

• All vessels will maintain a separation distance of 100 m (330 ft) or greater from any sighted non-delphinoid cetacean. If sighted, the vessel underway must reduce speed and shift the engine to neutral, and must not engage the engines until the non-delphinoid cetacean has moved outside of the vessel's path and beyond 100 m. If a survey vessel is stationary, the vessel will not engage engines until the non-delphinoid cetacean has moved out of the vessel's path and beyond 100 m;

• All vessels will maintain a separation distance of 50 m (164 ft) or greater from any sighted delphinoid cetacean. Any vessel underway remain parallel to a sighted delphinoid cetacean's course whenever possible, and avoid excessive speed or abrupt changes in direction. Any vessel underway reduces vessel speed to 10 knots (18.5 km/hr) or less when pods (including mother/calf pairs) or large assemblages of delphinoid cetaceans are observed. Vessels may not adjust course and speed until the delphinoid cetaceans have moved beyond 50 m and/or the abeam of the underway vessel;

• All vessels underway will not divert or alter course in order to approach any whale, delphinoid cetacean, or pinniped. Any vessel underway will avoid excessive speed or abrupt changes in direction to avoid injury to the sighted cetacean or pinniped; and

• All vessels will maintain a separation distance of 50 m (164 ft) or greater from any sighted pinniped.

The training program would be provided to NMFS for review and approval prior to the start of surveys. Confirmation of the training and understanding of the requirements will be documented on a training course log sheet. Signing the log sheet will certify that the crew members understand and will comply with the necessary requirements throughout the survey event.

Between watch shifts, members of the monitoring team will consult NMFS' North Atlantic right whale reporting systems for the presence of North Atlantic right whales throughout survey operations. However, the proposed survey activities will occur outside of the SMA located off the coasts of New Jersey and New York. Members of the monitoring team will monitor the NMFS North Atlantic right whale reporting systems for the establishment of a Dynamic Management Area (DMA). If NMFS should establish a DMA in the survey area, within 24 hours of the establishment of the DMA Statoil will work with NMFS to shut down and/or alter the survey activities to avoid the DMA.

The proposed mitigation measures are designed to avoid the already low potential for injury in addition to some Level B harassment, and to minimize the potential for vessel strikes. There are no known marine mammal feeding areas, rookeries, or mating grounds in the survey area that would otherwise potentially warrant increased mitigation measures for marine mammals or their habitat (or both). The proposed survey would occur in an area that has been identified as a biologically important area for migration for North Atlantic right whales. However, given the small spatial extent of the survey area relative to the substantially larger spatial extent of the right whale migratory area, the survey is not expected to appreciably reduce migratory habitat nor to negatively impact the migration of North Atlantic right whales, thus mitigation to address the proposed survey's occurrence in North Atlantic right whale migratory habitat is not warranted. Further, we believe the proposed mitigation measures are practicable for the applicant to implement.

Based on our evaluation of the applicant's proposed measures, NMFS has preliminarily determined that the proposed mitigation measures provide the means of effecting the least practicable impact on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.

In order to issue an IHA for an activity, Section 101(a)(5)(D) of the MMPA states that NMFS must set forth, requirements pertaining to the monitoring and reporting of such taking. The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for authorizations must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present in the proposed action area. Effective reporting is critical both to compliance as well as ensuring that the most value is obtained from the required monitoring.

Monitoring and reporting requirements prescribed by NMFS should contribute to improved understanding of one or more of the following:

• Occurrence of marine mammal species or stocks in the area in which take is anticipated (e.g., presence, abundance, distribution, density);

• Nature, scope, or context of likely marine mammal exposure to potential stressors/impacts (individual or cumulative, acute or chronic), through better understanding of: (1) Action or environment (e.g., source characterization, propagation, ambient noise); (2) affected species (e.g., life history, dive patterns); (3) co-occurrence of marine mammal species with the action; or (4) biological or behavioral context of exposure (e.g., age, calving or feeding areas);

• Individual marine mammal responses (behavioral or physiological) to acoustic stressors (acute, chronic, or cumulative), other stressors, or cumulative impacts from multiple stressors;

• How anticipated responses to stressors impact either: (1) Long-term fitness and survival of individual marine mammals; or (2) populations, species, or stocks;

• Effects on marine mammal habitat (e.g., marine mammal prey species, acoustic habitat, or other important physical components of marine mammal habitat); and

• Mitigation and monitoring effectiveness.

As described above, visual monitoring of the EZs and monitoring zone will be performed by qualified and NMFS-approved PSOs. Observer qualifications will include direct field experience on a marine mammal observation vessel and/or aerial surveys and completion of a PSO and/or PAM training program, as appropriate. As proposed by the applicant and required by BOEM, an observer team comprising a minimum of four NMFS-approved PSOs and a minimum of two certified PAM operator(s), operating in shifts, will be employed by Statoil during the proposed surveys. PSOs and PAM operators will work in shifts such that no one monitor will work more than 4 consecutive hours without a 2 hour break or longer than 12 hours during any 24-hour period. During daylight hours the PSOs will rotate in shifts of one on and three off, while during nighttime operations PSOs will work in pairs (per BOEM's requirements?). The PAM operators will also be on call as necessary during daytime operations should visual observations become impaired. Each PSO will monitor 360 degrees of the field of vision. Statoil will provide resumes of all proposed PSOs and PAM operators (including alternates) to NMFS for review and approval at least 45 days prior to the start of survey operations.

Also as described above, PSOs will be equipped with binoculars and have the ability to estimate distances to marine mammals located in proximity to the vessel and/or exclusion zone using range finders. Reticulated binoculars will also be available to PSOs for use as appropriate based on conditions and visibility to support the siting and monitoring of marine species. Digital single-lens reflex camera equipment will be used to record sightings and verify species identification. During night operations, PAM, night-vision equipment, and infrared technology will be used to increase the ability to detect marine mammals. Position data will be recorded using hand-held or vessel global positioning system (GPS) units for each sighting. Observations will take place from the highest available vantage point on the survey vessel. General 360-degree scanning will occur during the monitoring periods, and target scanning by the PSO will occur when alerted of a marine mammal presence.

Data on all PAM/PSO observations will be recorded based on standard PSO collection requirements. This will include dates and locations of survey operations; time of observation, location and weather; details of the sightings (e.g., species, age classification [if known], numbers, behavior); and details of any observed “taking” (behavioral disturbances). The data sheet will be provided to NMFS for review and approval prior to the start of survey activities. In addition, prior to initiation of survey work, all crew members will undergo environmental training, a component of which will focus on the procedures for sighting and protection of marine mammals. A briefing will also be conducted between the survey supervisors and crews, the PSOs, and Statoil. The purpose of the briefing will be to establish responsibilities of each party, define the chains of command, discuss communication procedures, provide an overview of monitoring purposes, and review operational procedures.

Acoustic Field Verification—As described above, field verification of sound levels associated with survey equipment will be conducted. Results of the field verification may be used to request modification of the EZs and monitoring zones. The details of the applicant's plan for field verification of sound levels are provided as Appendix B to the IHA application.

Statoil will provide the following reports as necessary during survey activities:

• The Applicant will contact NMFS within 24 hours of the commencement of survey activities and again within 24 hours of the completion of the activity.

• Notification of Injured or Dead Marine Mammals—In the unanticipated event that the specified HRG and geotechnical activities lead to an injury of a marine mammal (Level A harassment) or mortality (e.g., ship-strike, gear interaction, and/or entanglement), Statoil would immediately cease the specified activities and report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources and the NMFS Greater Atlantic Stranding Coordinator. The report would include the following information:

• Time, date, and location (latitude/longitude) of the incident;

• Name and type of vessel involved;

• Vessel's speed during and leading up to the incident;

• Description of the incident;

• Status of all sound source use in the 24 hours preceding the incident;

• Water depth;

• Environmental conditions (e.g., wind speed and direction, Beaufort sea state, cloud cover, and visibility);

• Description of all marine mammal observations in the 24 hours preceding the incident;

• Species identification or description of the animal(s) involved;

• Fate of the animal(s); and

• Photographs or video footage of the animal(s) (if equipment is available).

Activities would not resume until NMFS is able to review the circumstances of the event. NMFS would work with Statoil to minimize reoccurrence of such an event in the future. Statoil would not resume activities until notified by NMFS.

In the event that Statoil discovers an injured or dead marine mammal and determines that the cause of the injury or death is unknown and the death is relatively recent (i.e., in less than a moderate state of decomposition), Statoil would immediately report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources and the NMFS Greater Atlantic Stranding Coordinator. The report would include the same information identified in the paragraph above. Activities would be able to continue while NMFS reviews the circumstances of the incident. NMFS would work with Statoil to determine if modifications in the activities are appropriate.

In the event that Statoil discovers an injured or dead marine mammal and determines that the injury or death is not associated with or related to the activities authorized in the IHA (e.g., previously wounded animal, carcass with moderate to advanced decomposition, or scavenger damage), Statoil would report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources, and the NMFS Greater Atlantic Regional Stranding Coordinator, within 24 hours of the discovery. Statoil would provide photographs or video footage (if available) or other documentation of the stranded animal sighting to NMFS. Statoil may continue its operations under such a case.

• Within 90 days after completion of survey activities, a final technical report will be provided to NMFS that fully documents the methods and monitoring protocols, summarizes the data recorded during monitoring, estimates the number of marine mammals estimated to have been taken during survey activities, and provides an interpretation of the results and effectiveness of all mitigation and monitoring. Any recommendations made by NMFS must be addressed in the final report prior to acceptance by NMFS.

NMFS has defined negligible impact as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival. A negligible impact finding is based on the lack of likely adverse effects on annual rates of recruitment or survival (i.e., population-level effects). An estimate of the number of takes alone is not enough information on which to base an impact determination. In addition to considering estimates of the number of marine mammals that might be “taken” through harassment, NMFS considers other factors, such as the likely nature of any responses (e.g., intensity, duration), the context of any responses (e.g., critical reproductive time or location, migration), as well as effects on habitat, and the likely effectiveness of the mitigation. We also assess the number, intensity, and context of estimated takes by evaluating this information relative to population status. Consistent with the 1989 preamble for NMFS's implementing regulations (54 FR 40338; September 29, 1989), the impacts from other past and ongoing anthropogenic activities are incorporated into this analysis via their impacts on the environmental baseline (e.g., as reflected in the regulatory status of the species, population size and growth rate where known, ongoing sources of human-caused mortality, or ambient noise levels).

To avoid repetition, our analysis applies to all the species listed in Table 9, given that NMFS expects the anticipated effects of the proposed survey to be similar in nature.

NMFS does not anticipate that serious injury or mortality would occur as a result of Statoil's proposed survey, even in the absence of proposed mitigation. Thus the proposed authorization does not authorize any serious injury or mortality. As discussed in the Potential Effects section, non-auditory physical effects and vessel strike are not expected to occur.

We expect that all potential takes would be in the form of short-term Level B behavioral harassment in the form of temporary avoidance of the area or decreased foraging (if such activity were occurring), reactions that are considered to be of low severity and with no lasting biological consequences (e.g., Southall et al., 2007).

Potential impacts to marine mammal habitat were discussed previously in this document (see Potential Effects of the Specified Activity on Marine Mammals and their Habitat). Marine mammal habitat may be impacted by elevated sound levels, but these impacts would be temporary. In addition to being temporary and short in overall duration, the acoustic footprint of the proposed survey is small relative to the overall distribution of the animals in the area and their use of the area. Feeding behavior is not likely to be significantly impacted, as no areas of biological significance for marine mammal feeding are known to exist in the survey area. Prey species are mobile and are broadly distributed throughout the project area; therefore, marine mammals that may be temporarily displaced during survey activities are expected to be able to resume foraging once they have moved away from areas with disturbing levels of underwater noise. Because of the temporary nature of the disturbance, the availability of similar habitat and resources in the surrounding area, and the lack of important or unique marine mammal feeding habitat, the impacts to marine mammals and the food sources that they utilize are not expected to cause significant or long-term consequences for individual marine mammals or their populations. In addition, there are no rookeries or mating or calving areas known to be biologically important to marine mammals within the proposed project area. The proposed survey area is within a biologically important migratory area for North Atlantic right whales (effective March-April and November-December) that extends from Massachusetts to Florida (LaBrecque, et al., 2015). Off the coast of New York, this biologically important migratory area extends from the coast to the shelf break. Due to the fact that that the proposed survey is temporary and short in overall duration, and the fact that the spatial acoustic footprint of the proposed survey is very small relative to the spatial extent of the available migratory habitat in the area, right whale migration is not expected to be impacted by the proposed survey.

The proposed mitigation measures are expected to reduce the number and/or severity of takes by (1) giving animals the opportunity to move away from the sound source before HRG survey equipment reaches full energy; (2) preventing animals from being exposed to sound levels that may otherwise result in injury. Additional vessel strike avoidance requirements will further mitigate potential impacts to marine mammals during vessel transit to and within the survey area.

NMFS concludes that exposures to marine mammal species and stocks due to Statoil's proposed survey would result in only short-term (temporary and short in duration) effects to individuals exposed. Marine mammals may temporarily avoid the immediate area, but are not expected to permanently abandon the area. Major shifts in habitat use, distribution, or foraging success are not expected. NMFS does not anticipate the proposed take estimates to impact annual rates of recruitment or survival.

In summary and as described above, the following factors primarily support our preliminary determination that the impacts resulting from this activity are not expected to adversely affect the species or stock through effects on annual rates of recruitment or survival:

• No mortality, serious injury, or Level A harassment is anticipated or authorized;

• The anticipated impacts of the proposed activity on marine mammals would be temporary behavioral changes due to avoidance of the area around the survey vessel;

• The availability of alternate areas of similar habitat value for marine mammals to temporarily vacate the survey area during the proposed survey to avoid exposure to sounds from the activity;

• The proposed project area does not contain areas of significance for feeding, mating or calving;

• Effects on species that serve as prey species for marine mammals from the proposed survey are not expected;

• The proposed mitigation measures, including visual and acoustic monitoring and shutdowns, are expected to minimize potential impacts to marine mammals.

Based on the analysis contained herein of the likely effects of the specified activity on marine mammals and their habitat, and taking into consideration the implementation of the proposed monitoring and mitigation measures, NMFS preliminarily finds that the total marine mammal take from the proposed activity will have a negligible impact on all affected marine mammal species or stocks.

As noted above, only small numbers of incidental take may be authorized under Section 101(a)(5)(D) of the MMPA for specified activities other than military readiness activities. The MMPA does not define small numbers and so, in practice, where estimated numbers are available, NMFS compares the number of individuals taken to the most appropriate estimation of abundance of the relevant species or stock in our determination of whether an authorization is limited to small numbers of marine mammals. Additionally, other qualitative factors may be considered in the analysis, such as the temporal or spatial scale of the activities.

The numbers of marine mammals that we propose for authorization to be taken, for all species and stocks, would be considered small relative to the relevant stocks or populations (less than 6 percent of each species and stock). See Table 9. Based on the analysis contained herein of the proposed activity (including the proposed mitigation and monitoring measures) and the anticipated take of marine mammals, NMFS preliminarily finds that small numbers of marine mammals will be taken relative to the population size of the affected species or stocks.

There are no relevant subsistence uses of the affected marine mammal stocks or species implicated by this action. Therefore, NMFS has determined that the total taking of affected species or stocks would not have an unmitigable adverse impact on the availability of such species or stocks for taking for subsistence purposes.

Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq.) requires that each Federal agency insure that any action it authorizes, funds, or carries out is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of designated critical habitat. To ensure ESA compliance for the issuance of IHAs, NMFS consults internally, in this case with the NMFS Greater Atlantic Regional Fisheries Office (GARFO), whenever we propose to authorize take for endangered or threatened species.

The NMFS Office of Protected Resources is proposing to authorize the incidental take of three species of marine mammals which are listed under the ESA: The North Atlantic right, fin, and sperm whale. BOEM consulted with NMFS GARFO under section 7 of the ESA on commercial wind lease issuance and site assessment activities on the Atlantic Outer Continental Shelf in Massachusetts, Rhode Island, New York and New Jersey Wind Energy Areas. NMFS GARFO issued a Biological Opinion concluding that these activities may adversely affect but are not likely to jeopardize the continued existence of the North Atlantic right, fin, and sperm whale. The Biological Opinion can be found online at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. NMFS will conclude the ESA section 7 consultation prior to reaching a determination regarding the proposed issuance of the authorization. If the IHA is issued, the Biological Opinion may be amended to include an incidental take statement for these marine mammal species, as appropriate.

As a result of these preliminary determinations, NMFS proposes to issue an IHA to Statoil for conducting marine site assessment surveys offshore New York and along potential submarine cable routes from the date of issuance for a period of one year, provided the previously mentioned mitigation, monitoring, and reporting requirements are incorporated. This section contains a draft of the IHA itself. The wording contained in this section is proposed for inclusion in the IHA (if issued).

1. This IHA is valid for a period of one year from the date of issuance.

2. This IHA is valid only for marine site characterization survey activity, as specified in the IHA application, in the Atlantic Ocean.

3. General Conditions.

(a) A copy of this IHA must be in the possession of Statoil Wind U.S. LLC (Statoil), the vessel operator and other relevant personnel, the lead PSO, and any other relevant designees of Statoil operating under the authority of this IHA.

(b) The species authorized for taking are listed in Table 9. The taking, by Level B harassment only, is limited to the species and numbers listed in Table 9. Any taking of species not listed in Table 9, or exceeding the authorized amounts listed in Table 9, is prohibited and may result in the modification, suspension, or revocation of this IHA.

(c) The taking by injury, serious injury or death of any species of marine mammal is prohibited and may result in the modification, suspension, or revocation of this IHA.

(d) Statoil shall ensure that the vessel operator and other relevant vessel personnel are briefed on all responsibilities, communication procedures, marine mammal monitoring protocols, operational procedures, and IHA requirements prior to the start of survey activity, and when relevant new personnel join the survey operations.

4. Mitigation Requirements—the holder of this Authorization is required to implement the following mitigation measures:

(a) Statoil shall use at least four (4) NMFS-approved protected species observers (PSOs) during HRG surveys. The PSOs must have no tasks other than to conduct observational effort, record observational data, and communicate with and instruct relevant vessel crew with regard to the presence of marine mammals and mitigation requirements. PSO resumes shall be provided to NMFS for approval prior to commencement of the survey.

(b) Visual monitoring must begin no less than 30 minutes prior to initiation of survey equipment and must continue until 30 minutes after use of survey equipment ceases.

(c) Exclusion Zones and Watch Zone—PSOs shall establish and monitor marine mammal Exclusion Zones and Watch Zones. The Watch Zone shall represent the extent of the Level B harassment zone (1,166 m) or, as far as possible if the extent of the Level B zone is not fully visible. The Exclusion Zones are as follows:

(i) a 50 m Exclusion Zone for pinnipeds and delphinids (except harbor porpoises);

(ii) a 100 m Exclusion Zone for large whales including sperm whales and mysticetes (except North Atlantic right whales) and harbor porpoises;

(iii) a 500 m Exclusion Zone for North Atlantic right whales.

(d) Shutdown requirements—If a marine mammal is observed within, entering, or approaching the relevant Exclusion Zones as described under 4(c) while geophysical survey equipment is operational, the geophysical survey equipment must be immediately shut down.

(i) Any PSO on duty has the authority to call for shutdown of survey equipment. When there is certainty regarding the need for mitigation action on the basis of visual detection, the relevant PSO(s) must call for such action immediately.

(ii) When a shutdown is called for by a PSO, the shutdown must occur and any dispute resolved only following shutdown.

(iii) The shutdown requirement is waived for small delphinoids that approach the vessel (e.g., bow ride).

(iv) Upon implementation of a shutdown, survey equipment may be reactivated when all marine mammals have been confirmed by visual observation to have exited the relevant Exclusion Zone or an additional time period has elapsed with no further sighting of the animal that triggered the shutdown (15 minutes for small delphinoid cetaceans and pinnipeds and 30 minutes for all other species).

(v) If geophysical equipment shuts down for reasons other than mitigation (i.e., mechanical or electronic failure) resulting in the cessation of the survey equipment for a period of less than 20 minutes, the equipment may be restarted as soon as practicable if visual surveys were continued diligently throughout the silent period and the relevant Exclusion Zones are confirmed by PSOs to have remained clear of marine mammals during the entire 20 minute period. If visual surveys were not continued diligently during the pause of 20 minutes or less, a 30 minute pre-clearance period shall precede the restart of the geophysical survey equipment as described in 4(e). If the period of shutdown for reasons other than mitigation is greater than 20 minutes, a pre-clearance period shall precede the restart of the geophysical survey equipment as described in 4(e).

(e) Pre-clearance observation—30 minutes of pre-clearance observation shall be conducted prior to initiation of geophysical survey equipment. geophysical survey equipment shall not be initiated if marine mammals are observed within or approaching the relevant Exclusion Zones as described under 4(d) during the pre-clearance period. If a marine mammal is observed within or approaching the relevant Exclusion Zone during the pre-clearance period, geophysical survey equipment shall not be initiated until the animal(s) is confirmed by visual observation to have exited the relevant Exclusion Zone or until an additional time period has elapsed with no further sighting of the animal (15 minutes for small delphinoid cetaceans and pinnipeds and 30 minutes for all other species).

(f) Ramp-up—when technically feasible, survey equipment shall be ramped up at the start or re-start of survey activities. Ramp-up will begin with the power of the smallest acoustic equipment at its lowest practical power output appropriate for the survey. When technically feasible the power will then be gradually turned up and other acoustic sources added in way such that the source level would increase gradually.

(g) Vessel Strike Avoidance—Vessel operator and crew must maintain a vigilant watch for all marine mammals and slow down or stop the vessel or alter course, as appropriate, to avoid striking any marine mammal, unless such action represents a human safety concern. Survey vessel crew members responsible for navigation duties shall receive site-specific training on marine mammal sighting/reporting and vessel strike avoidance measures. Vessel strike avoidance measures shall include the following, except under circumstances when complying with these requirements would put the safety of the vessel or crew at risk:

(i) The vessel operator and crew shall maintain vigilant watch for cetaceans and pinnipeds, and slow down or stop the vessel to avoid striking marine mammals;

(ii) The vessel operator will reduce vessel speed to 10 knots (18.5 km/hr) or less when any large whale, any mother/calf pairs, whale or dolphin pods, or larger assemblages of non-delphinoid cetaceans are observed near (within 100 m (330 ft)) an underway vessel;

(iii) The survey vessel will maintain a separation distance of 500 m (1640 ft) or greater from any sighted North Atlantic right whale;

(iv) If underway, the vessel must steer a course away from any sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less until the 500 m (1640 ft) minimum separation distance has been established. If a North Atlantic right whale is sighted in a vessel's path, or within 100 m (330 ft) to an underway vessel, the underway vessel must reduce speed and shift the engine to neutral. Engines will not be engaged until the North Atlantic right whale has moved outside of the vessel's path and beyond 100 m. If stationary, the vessel must not engage engines until the North Atlantic right whale has moved beyond 100 m;

(v) The vessel will maintain a separation distance of 100 m (330 ft) or greater from any sighted non-delphinoid cetacean. If sighted, the vessel underway must reduce speed and shift the engine to neutral, and must not engage the engines until the non-delphinoid cetacean has moved outside of the vessel's path and beyond 100 m. If a survey vessel is stationary, the vessel will not engage engines until the non-delphinoid cetacean has moved out of the vessel's path and beyond 100 m;

(vi) The vessel will maintain a separation distance of 50 m (164 ft) or greater from any sighted delphinoid cetacean. Any vessel underway remain parallel to a sighted delphinoid cetacean's course whenever possible, and avoid excessive speed or abrupt changes in direction. Any vessel underway reduces vessel speed to 10 knots (18.5 km/hr) or less when pods (including mother/calf pairs) or large assemblages of delphinoid cetaceans are observed. Vessels may not adjust course and speed until the delphinoid cetaceans have moved beyond 50 m and/or the abeam of the underway vessel;

(vii) All vessels underway will not divert or alter course in order to approach any whale, delphinoid cetacean, or pinniped. Any vessel underway will avoid excessive speed or abrupt changes in direction to avoid injury to the sighted cetacean or pinniped; and

(viii) All vessels will maintain a separation distance of 50 m (164 ft) or greater from any sighted pinniped.

(ix) The vessel operator will comply with 10 knot (18.5 km/hr) or less speed restrictions in any Seasonal Management Area per NMFS guidance.

(x) If NMFS should establish a Dynamic Management Area (DMA) in the area of the survey, within 24 hours of the establishment of the DMA Statoil shall work with NMFS to shut down and/or alter survey activities to avoid the DMA as appropriate.

5. Monitoring Requirements—The Holder of this Authorization is required to conduct marine mammal visual monitoring and passive acoustic monitoring (PAM) during geophysical survey activity. Monitoring shall be conducted in accordance with the following requirements:

(a) A minimum of four NMFS-approved PSOs and a minimum of two certified (PAM) operator(s), operating in shifts, shall be employed by Statoil during geophysical surveys.

(b) Observations shall take place from the highest available vantage point on the survey vessel. General 360-degree scanning shall occur during the monitoring periods, and target scanning by PSOs will occur when alerted of a marine mammal presence.

(c) PSOs shall be equipped with binoculars and have the ability to estimate distances to marine mammals located in proximity to the vessel and/or Exclusion Zones using range finders. Reticulated binoculars will also be available to PSOs for use as appropriate based on conditions and visibility to support the sighting and monitoring of marine species. Digital single-lens reflex camera equipment will be used to record sightings and verify species identification.

(d) PAM shall be used during nighttime geophysical survey operations. The PAM system shall consist of an array of hydrophones with both broadband (sampling mid-range frequencies of 2 kHz to 200 kHz) and at least one low-frequency hydrophone (sampling range frequencies of 75 Hz to 30 kHz). PAM operators shall communicate detections or vocalizations to the Lead PSO on duty who shall ensure the implementation of the appropriate mitigation measure.

(e) During night surveys, night-vision equipment and infrared technology shall be used in addition to PAM. Specifications for night-vision and infrared equipment shall be provided to NMFS for review and acceptance prior to start of surveys.

(f) PSOs and PAM operators shall work in shifts such that no one monitor will work more than 4 consecutive hours without a 2 hour break or longer than 12 hours during any 24-hour period. During daylight hours the PSOs shall rotate in shifts of 1 on and 3 off, and while during nighttime operations PSOs shall work in pairs.

(g) PAM operators shall also be on call as necessary during daytime operations should visual observations become impaired.

(h) Position data shall be recorded using hand-held or vessel global positioning system (GPS) units for each sighting.

(i) A briefing shall be conducted between survey supervisors and crews, PSOs, and Statoil to establish responsibilities of each party, define chains of command, discuss communication procedures, provide an overview of monitoring purposes, and review operational procedures.

(j) Statoil shall provide resumes of all proposed PSOs and PAM operators (including alternates) to NMFS for review and approval at least 45 days prior to the start of survey operations.

(k) PSO Qualifications shall include direct field experience on a marine mammal observation vessel and/or aerial surveys.

(a) Data on all PAM/PSO observations shall be recorded based on standard PSO collection requirements. PSOs must use standardized data forms, whether hard copy or electronic. The following information shall be reported:

(i) PSO names and affiliations.

(ii) Dates of departures and returns to port with port name.

(iii) Dates and times (Greenwich Mean Time) of survey effort and times corresponding with PSO effort.

(iv) Vessel location (latitude/longitude) when survey effort begins and ends; vessel location at beginning and end of visual PSO duty shifts.

(v) Vessel heading and speed at beginning and end of visual PSO duty shifts and upon any line change.

(vi) Environmental conditions while on visual survey (at beginning and end of PSO shift and whenever conditions change significantly), including wind speed and direction, Beaufort sea state, Beaufort wind force, swell height, weather conditions, cloud cover, sun glare, and overall visibility to the horizon.

(vii) Factors that may be contributing to impaired observations during each PSO shift change or as needed as environmental conditions change (e.g., vessel traffic, equipment malfunctions).

(viii) Survey activity information, such as acoustic source power output while in operation, number and volume of airguns operating in the array, tow depth of the array, and any other notes of significance (i.e., pre-ramp-up survey, ramp-up, shutdown, testing, shooting, ramp-up completion, end of operations, streamers, etc.).

(ix) If a marine mammal is sighted, the following information should be recorded:

(A) Watch status (sighting made by PSO on/off effort, opportunistic, crew, alternate vessel/platform);

(B) PSO who sighted the animal;

(C) Time of sighting;

(D) Vessel location at time of sighting;

(E) Water depth;

(F) Direction of vessel's travel (compass direction);

(G) Direction of animal's travel relative to the vessel;

(H) Pace of the animal;

(I) Estimated distance to the animal and its heading relative to vessel at initial sighting;

(J) Identification of the animal (e.g., genus/species, lowest possible taxonomic level, or unidentified); also note the composition of the group if there is a mix of species;

(K) Estimated number of animals (high/low/best);

(L) Estimated number of animals by cohort (adults, yearlings, juveniles, calves, group composition, etc.);

(M) Description (as many distinguishing features as possible of each individual seen, including length, shape, color, pattern, scars or markings, shape and size of dorsal fin, shape of head, and blow characteristics);

(N) Detailed behavior observations (e.g., number of blows, number of surfaces, breaching, spyhopping, diving, feeding, traveling; as explicit and detailed as possible; note any observed changes in behavior);

(O) Animal's closest point of approach and/or closest distance from the center point of the acoustic source;

(P) Platform activity at time of sighting (e.g., deploying, recovering, testing, data acquisition, other); and

(Q) Description of any actions implemented in response to the sighting (e.g., delays, shutdown, ramp-up, speed or course alteration, etc.) and time and location of the action.

6. Reporting—a technical report shall be provided to NMFS within 90 days after completion of survey activities that fully documents the methods and monitoring protocols, summarizes the data recorded during monitoring, estimates the number of marine mammals that may have been taken during survey activities, describes the effectiveness of the various mitigation techniques (i.e. visual observations during day and night compared to PAM detections/operations) and provides an interpretation of the results and effectiveness of all monitoring tasks. Any recommendations made by NMFS shall be addressed in the final report prior to acceptance by NMFS.

(a) Reporting injured or dead marine mammals:

(i) In the event that the specified activity clearly causes the take of a marine mammal in a manner not prohibited by this IHA (if issued), such as serious injury or mortality, Statoil shall immediately cease the specified activities and immediately report the incident to NMFS. The report must include the following information:

(A) Time, date, and location (latitude/longitude) of the incident;

(B) Vessel's speed during and leading up to the incident;

(C) Description of the incident;

(D) Status of all sound source use in the 24 hours preceding the incident;

(E) Water depth;

(F) Environmental conditions (e.g., wind speed and direction, Beaufort sea state, cloud cover, and visibility);

(G) Description of all marine mammal observations in the 24 hours preceding the incident;

(H) Species identification or description of the animal(s) involved;

(I) Fate of the animal(s); and

(J) Photographs or video footage of the animal(s).

Activities shall not resume until NMFS is able to review the circumstances of the prohibited take. NMFS will work with Statoil to determine what measures are necessary to minimize the likelihood of further prohibited take and ensure MMPA compliance. Statoil may not resume their activities until notified by NMFS.

(ii) In the event that Statoil discovers an injured or dead marine mammal, and the lead PSO determines that the cause of the injury or death is unknown and the death is relatively recent (e.g., in less than a moderate state of decomposition), Statoil shall immediately report the incident to NMFS. The report must include the same information identified in condition 6(b)(i) of this IHA. Activities may continue while NMFS reviews the circumstances of the incident. NMFS will work with Statoil to determine whether additional mitigation measures or modifications to the activities are appropriate.

(iii) In the event that Statoil discovers an injured or dead marine mammal, and the lead PSO determines that the injury or death is not associated with or related to the specified activities (e.g., previously wounded animal, carcass with moderate to advanced decomposition, or scavenger damage), Statoil shall report the incident to NMFS within 24 hours of the discovery. Statoil shall provide photographs or video footage or other documentation of the sighting to NMFS.

7. This Authorization may be modified, suspended or withdrawn if the holder fails to abide by the conditions prescribed herein, or if NMFS determines the authorized taking is having more than a negligible impact on the species or stock of affected marine mammals.

We request comment on our analyses, the draft authorization, and any other aspect of this Notice of Proposed IHA for the proposed marine site characterization surveys. Please include with your comments any supporting data or literature citations to help inform our final decision on the request for MMPA authorization.

On a case-by-case basis, NMFS may issue a one-year renewal IHA without additional notice when (1) another year of identical or nearly identical activities as described in the Specified Activities section is planned, or (2) the activities would not be completed by the time the IHA expires and renewal would allow completion of the activities beyond that described in the Dates and Duration section, provided all of the following conditions are met:

• A request for renewal is received no later than 60 days prior to expiration of the current IHA.

• The request for renewal must include the following:

(1) An explanation that the activities to be conducted beyond the initial dates either are identical to the previously analyzed activities or include changes so minor (e.g., reduction in pile size) that the changes do not affect the previous analyses, take estimates, or mitigation and monitoring requirements.

(2) A preliminary monitoring report showing the results of the required monitoring to date and an explanation showing that the monitoring results do not indicate impacts of a scale or nature not previously analyzed or authorized.

• Upon review of the request for renewal, the status of the affected species or stocks, and any other pertinent information, NMFS determines that there are no more than minor changes in the activities, the mitigation and monitoring measures remain the same and appropriate, and the original findings remain valid.

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.

An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth.

NMFS has defined “negligible impact” in 50 CFR 216.103 as “. . . an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.”

The MMPA states that the term “take” means to harass, hunt, capture, kill or attempt to harass, hunt, capture, or kill any marine mammal. Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as: Any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

To comply with the National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, NMFS must review our proposed action (i.e., the issuance of an incidental harassment authorization) with respect to potential impacts on the human environment.

This action is consistent with categories of activities identified in CE B4 of the Companion Manual for NOAA Administrative Order 216-6A, which do not individually or cumulatively have the potential for significant impacts on the quality of the human environment and for which we have not identified any extraordinary circumstances that would preclude this categorical exclusion. Accordingly, NMFS has preliminarily determined that the issuance of the proposed IHA qualifies to be categorically excluded from further NEPA review.

We will review all comments submitted in response to this notice prior to concluding our NEPA process or making a final decision on the IHA request.

On October 17, 2017, NMFS received a request from the City of Astoria (City) for an IHA to take marine mammals incidental to replacement of bridges in downtown Astoria along the Columbia River. The application was considered adequate and complete on January 17, 2018. The City's request is for take of California sea lions (Zalophus californianus), Steller sea lions (Eumetopias jubatus), and harbor seals (Phoca vitulina richardii) by Level B harassment only. Neither the City nor NMFS expect mortality to result from this activity and, therefore, an IHA is appropriate.

The City is seeking an IHA for the first year of a two-year project to remove and replace piles supporting six waterfront bridges in Astoria, Oregon. Phase I of the project, which would occur under this IHA, involves the removal and replacement of three bridges connecting 7th, 9th, and 11th Streets to waterfront piers. The bridges are currently supported by decayed timber piles and concrete footings that will be removed and replaced with steel piles. Roadway construction, timber pile removal, and steel pile driving are expected to result in Level B auditory harassment of California sea lions, harbor seals, and Steller sea lions.

The proposed project would occur along the Lower Columbia River. The action area is not expected to exceed 1,600 meters (m) beyond each bridge site. Construction for Phase I of the project, removing and replacing the 7th, 9th, and 11th Street bridge crossings, is expected to occur between October 2018 and April 2019.

Project work is expected to begin in October 2018 with roadway and rail superstructure removal. Timber pile removal and steel pile installation will occur within the Oregon Department of Fish and Wildlife (ODFW) prescribed in-water work period (IWWP) for the Lower Columbia River (November 1 through February 28). Timber pile and concrete foundation removal will be initiated at the onset of the IWWP. These activities will likely occur over the entire IWWP, or 80 work days. Vibratory timber pile removal is expected to take approximately 26 days and impact hammer pile installation will take approximately 42 days. The remaining 12 days in the IWWP will be used to remove all concrete footings and a concrete retaining wall. The contractor will likely remove existing structures concurrent with construction of new foundations. Pile removal and installation will occur over an eight hour period each day.

Additional above-water construction may be completed between March 2019 and August 2019. Rail superstructure construction is expected to occur over 13 work days between March 1 and April 11. Construction of approach superstructure and roadway improvements will be conducted between April and August 2019. An offsite storm water facility will be constructed during the summer of 2019.

The project site is located in the Baker Bay-Columbia River subwatershed. This section of the Columbia River represents the most saline portion of the river's estuarine environment. Tidal influence extends 146 miles upriver to the Bonneville Dam. The Columbia River is over nine miles wide in the area around Astoria and contains multiple islands, buoys, and sandbars that marine mammals utilize to haul out. The upland portions of the region of activity have been highly altered by human activities, with substantial shoreline development and remnants of historical development. This includes thousands of timber piles, overwater buildings, a railroad trestle, and vehicular bridges. The downtown Astoria waterfront is a busy area for pedestrians, vehicles, and boats. In addition to onshore development, the Lower Columbia River is utilized by various types of vessels, including cargo ships, dredging vessels, fishing vessels, trawlers, pollution control vessels, and search and rescue vessels, among others.

The remainder of the region of activity is located within the river channel within the intertidal and subtidal zones. The substrate in this area is primarily made up of historical rip rap and other rocks/cobbles. All in-water construction will occur in the intertidal and subtidal zones. Some piles may be removed and installed completely in the dry while others may remain inundated in water over 75 percent of the time. Section 1 of the application describes the tidal conditions of each crossing in detail.

Phase I of the project involves the removal and replacement of three bridges connecting 7th, 9th, and 11th Streets to waterfront piers. Each bridge has pedestrian and vehicle access. A railroad trestle runs parallel to the shoreline between the bridges along the waterfront. Demolition of the existing bridge crossings will require the removal of bridge decks and other aboveground components for the rail trestle and roadway approaches. Demolition of the superstructures will likely be accomplished using standard roadway and bridge construction equipment. The existing bridge crossings are primarily founded on a timber substructure. All timber elements supporting the roadway approach and trestle crossing will be removed. Most of the structures are below the Mean High Water (MHW) elevation; the remaining timber elements are below the Mean Higher-High Water (MHHW) or the Highest Measured Tide (HMT) elevation, with only a few piles being removed landward of the HMT elevation. Each bridge contains 85 timber structures to be removed. Most timber piles are 12 inches (in) diameter but some may be up to 14 in. The contractor will use a vibratory hammer or direct pull to remove the timber piles. In addition to timber structures, each bridge is supported by concrete footings ranging in size from 16 in by 16 in to 12 feet (ft) by 3 ft. Seven concrete structures will be removed from the 7th Street crossing, four from the 9th Street crossing, and eight from the 11th Street crossing (Table 1). A concrete retaining wall at the 9th Street crossing will also be removed to facilitate construction of the new roadway approach. The wall is located below the HMT elevation and is frequently exposed to surface flows. The contractor will use a concrete saw to cut the retaining wall into manageable pieces.

Abutment wingwalls will be constructed at the 9th Street crossing to help contain the roadway approach fill. The wingwalls will be cast-in-place concrete retaining walls. The eastern retaining wall will be located above the HMT and the western wall will be above the MHHW. As a result, the work will be completed in the dry; however, the contractor will install measures when necessary to isolate the work area.

Most of the piles to be installed are within 40 ft of the existing abutments, so the piles will be installed from a crane staged on the south side of the bridges. However, piling at the 9th Street crossing is up to 60 ft from the south abutment. The size and length of the piling as well as the weight of the pile hammer and leads places additional demand on the supporting crane. As a result, the contractor will construct temporary shoring consisting of two bents comprised of five 16-in piles each for a total of ten piles. Both bents will be located within two ft of the MLW elevation. Therefore, all piles are likely to be inundated by water levels greater than 2 ft deep at least 75 percent of the time during installation and extraction. Construction of the work platform will be initiated following removal of the superstructures, retaining wall, and approach fill at the 9th Street crossing. Due to the soft soils, it is anticipated that each pile installed will advance predominately under its own weight with a limited number of impact hammer strikes prior to reaching the bedrock surface. To finish pile installation, the contractor will be required to use an impact hammer to secure the piles into the bedrock and verify the required bearing resistances. All temporary pilings will be installed and removed during the ODFW prescribed IWWP and will remain in place for only one construction season.

A total of 74 24-in diameter permanent steel piles are expected to be driven for Phase I of this project (21 at the 7th Street crossing, 25 at the 9th Street crossing, and 28 at the 11th Street crossing, Table 1). As with the temporary shoring, it is expected that the permanent piles will advance under their own weight with a limited number of hammer strikes before reaching the bedrock surface.

The IWWP prescribed by ODFW includes 80 work days. Construction work is assumed to occur over an eight hour period each day. It is assumed that the contractor will drive the first 40 ft of piling for each pile location (each pile location consists of two 40-foot pile sections) over the first few days of pile driving, then splice on the additional 40 ft of piling at each location over the next few days. After the first 40-ft pile section is driven, a backer bar is tack welded on to the first pile section, then the second pile section is aligned with a crane, and welded on. Once all of the piles are spliced, the contractor will resume pile driving activities to set each pile to the desired depth. It is estimated that the contractor can install four 40-foot piles a day at an estimated 250 strikes per pile. With a total of 84 piles to be driven (74 permanent and 10 temporary), given the rate of four 40-ft piles per day, impact pile driving will take 42 days with a total of 1000 strikes per day (Table 2). This would leave 38 work days for the removal of existing timber piling and concrete substructures. The contractor will attempt to extract the existing piles via direct pull or vibratory hammer. Vibratory removal of timber piles will take approximately 30 minutes per pile. A total of 255 timber piles are anticipated to be extracted. At an average of 10 piles removed per day, existing timber pile removal is expected to take 26 days (Table 2) which leaves 12 days remaining in the work period to cover the removal of all concrete footings and the 9th Street retaining wall. It is anticipated that the contractor will be removing existing substructure elements concurrent with the construction of the new foundations.

The construction activities that could potentially result in acoustic and visual disturbance to pinnipeds within the action area include rail and roadway superstructure and concrete foundation removal activities, temporary work platform construction, piling installation, wingwall construction, and construction of the new rail and roadway superstructures. Most of these activities will require work in water during the IWWP (November 1 through February 28). Sound from pile removal and installation will likely extend out into the river channel where California sea lions, Steller sea lions, and harbor seals may be transiting. Work occurring in-air includes the removal of bridge decks and other aboveground components for the rail trestle crossings and roadway approaches as well as construction of the new rail superstructures and roadway improvements, which occurs directly above the river banks where hauled out California sea lions may be located. California sea lions may be harassed by the presence of construction equipment during above-water construction.

Proposed mitigation, monitoring, and reporting measures are described in detail later in this document (please see “Proposed Mitigation” and “Proposed Monitoring and Reporting”).

Sections 3 and 4 of the application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history, of the potentially affected species. Additional information regarding population trends and threats may be found in NMFS's Stock Assessment Reports (SAR; https://www.fisheries.noaa.gov/topic/population-assessments/marine-mammals) and more general information about these species (e.g., physical and behavioral descriptions) may be found on NMFS's website (https://www.fisheries.noaa.gov/find-species).

Table 3 lists all species with expected potential for occurrence in Astoria and summarizes information related to the population or stock, including regulatory status under the MMPA and ESA and potential biological removal (PBR), where known. For taxonomy, we follow Committee on Taxonomy (2016). PBR is defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population (as described in NMFS's SARs). While no mortality is anticipated or authorized here, PBR and annual serious injury and mortality from anthropogenic sources are included here as gross indicators of the status of the species 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's 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's U.S. 2016 SARs (e.g., Caretta et al. 2017). All values presented in Table 3 are the most recent available at the time of publication and are available in the 2016 SARs (Caretta et al. 2017, Muto et al., 2017).

All species that could potentially occur in the proposed survey areas are included in Table 3. As described below, all three species temporally and spatially co-occur with the activity to the degree that take is reasonably likely to occur, and we have proposed authorizing it.

California sea lions (Zalophus californianus) are distributed along the North Pacific waters from central Mexico to southeast Alaska, with breeding areas restricted primarily to island areas off southern California (the Channel Islands), Baja California, and in the Gulf of California (Wright et al., 2010). California sea lions are dark brown with broad fore flippers and a long, narrow snout. There are five genetically distinct geographic populations. The population seen in Oregon is the Pacific Temperate stock, which are commonly seen in Oregon from September through May (ODFW 2015). The approximate growth rate for this species is 5.4 percent annually (Caretta et al., 2004). Threats to this species include incidental catch and entanglement in fishing gear, such as gillnets; biotoxins, as a result of harmful algal blooms; and gunshot wounds and other human-caused injuries, as California sea lions are sometimes viewed as a nuisance by commercial fishermen (NOAA 2016).

Almost all California sea lions in the Pacific Northwest are sub-adult or adult males (NOAA 2008). California sea lions feed in both the Columbia River and adjacent nearshore marine areas. Their population is lowest in Oregon in the summer months, from May to September, as they migrate south to the Channel Islands in California to breed. California sea lions have been observed near several crossings within the Project site; however, this is not their main haul out. Their main haul out is the East Mooring Basin, which is located over one mile upstream, outside of the Region of Activity. Construction activities are proposed between October and April, which includes the tail end of peak usage of the lower river by California sea lions. Counts of California sea lions are highest in September but taper off until March when the sea lions travel south past Oregon toward their breeding sites (Brown et al., 2015). Recent years have shown an increase in the record numbers of California sea lions at the East Mooring Basin with a 2015 spring record of 2,340 individuals (up from 1,420 in 2014), though in past years, typical spring counts were closer to 100-300 individuals (Profita 2015). Changes in climate, food sources, and a growing population approaching 300,000 are all cited as possible reasons for these increases. Counts of California sea lions at the South Jetty haulout at the mouth of the Columbia River (10 miles downstream of project site) date back to 1995 (ODFW 2007) but more reliable monthly counts from Washington Department of Fish and Wildlife (WDFW) are available from 2000-2014 (WDFW 2014).

The Pacific harbor seal (Phoca vitulina richardii) is the most widespread and abundant resident pinniped in Oregon. They are generally blue-gray with light and dark speckling; they lack external ear flaps and have short forelimbs. Harbor seals are generally non-migratory and occur on both the U.S. east and west coasts. On the west coast they range from Alaska to Baja California, Mexico (ODFW 2015).

The Oregon/Washington Coast stock abundance was estimated in 1999 to be 24,732. However, the data used to establish that abundance was eight years old at the time and no more recent stock abundance estimates exist (Caretta et al., 2017). The 1999 abundance estimate will be used for the purposes of this analysis. The Oregon/Washington Coast stock of Pacific harbor seals is not listed under the ESA nor are they considered depleted or strategic under the MMPA.

Harbor seals utilize specific shoreline locations on a regular basis as haulouts including beaches, rocks, floats, and buoys. They must rest at haulout locations to regulate body temperature, interact with one another, and sleep (NOAA 2016). Harbor seals are present throughout the year at the mouth of the Columbia River and adjacent nearshore marine areas. Harbor seals are an infrequent visitor at the Astoria Mooring Basin, but they are known to transit through the Region of Activity. Their closest haulout and pupping area is Desdemona Sands which is downstream of the Astoria-Megler Bridge and outside the Region of Activity. Pupping occurs from Mid-April to July, outside of the proposed project work period (Susan Riemer, pers. comm., 2016). Due to their year-round occurrence in the Columbia River, harbor seals are likely to be found transiting the area during in-water construction.

The Steller sea lion (Eumetopias jubatus) range extends along the Pacific Rim, from northern Japan to central California. For management purposes, Steller sea lions inhabiting U.S. waters have been divided into two DPS: The Western U.S. and the Eastern U.S. The population known to occur within the Lower Columbia River is the Eastern DPS. The Western U.S. stock of Steller sea lions are listed as endangered under the ESA and depleted and strategic under the MMPA. The Eastern U.S. stock (including those living in Oregon) was de-listed in 2013 following a population growth from 18,000 in 1979 to 70,000 in 2010 (an estimated annual growth of 4.18 percent) (NOAA 2013). The current abundance estimate for the Eastern U.S. stock is 41,638 (Muto et al., 2017). Threats to Steller sea lions include: Boat/ship strikes, contaminants/pollutants, habitat degradation, illegal hunting/shooting, offshore oil and gas exploration, and interactions (direct and indirect) with fisheries (NOAA 2016). Critical habitat was designated for Steller sea lions on August 27, 1993 (58 FR 45269), but is not present within the Region of Activity. Critical habitat is associated with specific breeding and haulout sites in Alaska, California, and Oregon (NOAA 2016).

Steller sea lions are present year-round at the mouth of the Columbia River, with the primary haulout point on the top South Jetty (approximately 10 miles downstream of the action area) and they are at their peak in the lower river from September through March. The South Jetty haulout is the only artificial structure Steller sea lions regularly use along the Oregon coast. Steller sea lions feed in both the Columbia River and adjacent nearshore marine areas. Due to their year-round presence and peak of presence during the winter months, Steller sea lions are likely to be transiting the area during in-water construction activities.

This section includes a summary and discussion of the ways that components of the specified activity may impact marine mammals and their habitat. The Estimated Take by Incidental Harassment 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 by Incidental Harassment 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 how those impacts on individuals are likely to impact marine mammal species or stocks.

Sound travels in waves, the basic components of which 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 of a sound wave; lower frequency sounds have longer wavelengths than higher frequency sounds. Amplitude is the height of the sound pressure wave or the `loudness' of a sound and is typically measured using the decibel (dB) scale. A dB is the ratio between a measured pressure (with sound) and a reference pressure (sound at a constant pressure, established by scientific standards). It is a logarithmic unit that accounts for large variations in amplitude; therefore, relatively small changes in dB ratings correspond to large changes in sound pressure. When referring to sound pressure levels (SPLs; the sound force per unit area), sound is referenced in the context of underwater sound pressure to 1 microPascal (µPa). One Pascal is the pressure resulting from a force of one Newton exerted over an area of one square meter. The source level (SL) represents the sound level at a distance of 1 m from the source (referenced to 1 µPa). The received level is the sound level at the listener's position. Note that all underwater sound levels in the document are referenced to a pressure of 1 µPa and all airborne sound levels in this document are referenced to a pressure of 20 µPa.

Root mean square (rms) is the quadratic mean sound pressure over the duration of an impulse. 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 pressures.

When underwater objects vibrate or activity occurs, sound-pressure waves are created. These waves alternately compress and decompress the water as the sound wave travels. Underwater sound waves radiate in all directions away from the source (similar to ripples on the surface of a pond), except in cases where the source is directional. The compressions and decompressions associated with sound waves are detected as changes in pressure by aquatic life and man-made sound receptors such as hydrophones.

Even in the absence of sound from the specified activity, the underwater environment is typically loud due to ambient sound. Ambient sound is defined as environmental background sound levels lacking a single source or point (Richardson et al., 1995), and 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., waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds produced by marine mammals, fish, and invertebrates), and anthropogenic sound (e.g., vessels, dredging, aircraft, construction). A number of sources contributed to ambient sound, including the following (Richardson et al., 1995):

• Wind and waves: The complex interactions between wind and water surface, including processes such as breaking waves and wave-induced bubble oscillations and cavitation, are a main source of naturally occurring ambient noise for frequencies between 200 Hz and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient sound levels tend to increase with increasing wind speed and wave height. Surf noise becomes important near shore, with measurements collected at a distance of 8.5 km from shore showing an increase of 10 dB in the 100 to 700 Hz band during heavy surf conditions.

• Precipitation: Sound from rain and hail impacting the water surface can become an important component of total noise frequencies above 500 Hz, and possibly down to 100 Hz during quiet times.

• Biological: Marine mammals can contribute significantly to ambient noise levels, as can some fish and shrimp. The frequency band for biological contributions is from approximately 12 Hz to over 100 kHz.

• Anthropogenic: Sources of ambient noise related to human activity include transportation (surface vessels and aircraft), dredging and construction, oil and gas drilling and production, seismic surveys, sonar, explosions, and ocean acoustic studies. Shipping noise typically dominates the total ambient noise for frequencies between 20 and 300 Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz and, if higher frequency sound levels are created, they attenuate rapidly (Richardson et al., 1995). Sound from identifiable anthropogenic sources other than the activity of interest (e.g., a passing vessel) is sometimes termed background sound, as opposed to ambient sound. Representative levels of anthropogenic sound are displayed in Table 4.

The sum of the various natural and anthropogenic sound sources at any given location and time—which comprise “ambient” or “background” sound—depends not only on the source levels (as determined by current weather conditions and levels of biological and shipping activity) but also on the ability of sound to propagate through the environment. In turn, 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, 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 10-20 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.

In-water construction activities associated with the Project include impact pile driving and vibratory pile removal. The sounds produced by these activities fall into one of two general sound types: pulsed and non-pulsed (defined in the following). The distinction between these two sound types is important because they have differing potential to cause physical effects, particularly with regard to hearing (e.g., Ward 1997 in Southall et al., 2007). Please see Southall et al., (2007) for an in-depth discussion of these concepts.

Pulsed sound sources (e.g., impact pile driving) product signals that are brief (typically considered to be less than one second), broadband, atonal transients (ANSI 1986; Harris 1998; NIOSH 1998; ISO 2003; ANSI 2005) and occur either as isolated events or repeated in some succession. Pulsed 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.

Non-pulsed sounds can be tonal, narrowband or broadband, brief or prolonged, and may be wither continuous or non-continuous (ANSI 1995; NIOSH 1998). Some of these non-pulsed sounds can be transient signals of short duration without the essential properties of pulses (e.g., rapid rise time). Examples of non-pulsed sounds include those produced by vessels, aircraft, machinery operations such as drilling or dredging, vibratory pile driving, and active sonar systems (such as those used by the U.S. Navy). The duration of such sounds, as received at a distance, can be greatly extended in a highly reverberant environment.

Impact hammers operate by repeatedly dropping a heavy piston onto a pile to drive the pile into the substrate. Sound generated by impact hammers is 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 produce significantly less sound 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., 2005).

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. Current data indicate that 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) recommended that marine mammals be divided into functional hearing groups based on directly measured or estimated hearing ranges on the basis of available behavioral response data, audiograms derived using auditory evoked potential techniques, anatomical modeling, and other data. Note that no direct measurements of hearing ability have been successfully completed for mysticetes (i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described generalized hearing ranges for these marine mammal hearing groups. Generalized hearing ranges were chosen based on the approximately 65 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. The functional groups and the associated frequencies are indicated below in Table 5 (note that these frequency ranges correspond to the range for the composite group, with the entire range not necessarily reflecting the capabilities of every species within that group).

The pinniped functional hearing group was modified from Southall et al. (2007) on the basis of data indicating that phocid species have consistently demonstrated an extended frequency range of hearing compared to otariids, especially in the higher frequency range (Hemilä et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 2013).

For more detail concerning these groups and associated frequency ranges, please see NMFS (2016) for a review of available information. As mentioned previously in this document, three marine mammal species (zero cetacean and three pinniped (two otariid and one phocid) species) have the reasonable potential to co-occur with the proposed activities (Table 3). Harbor seals are classified as members of the phocid pinnipeds in water functional hearing group, while Steller and California sea lions are grouped under the otariid pinnipeds in water functional hearing group. A species' functional hearing group is a consideration when we analyze the effects of exposure to sound on marine mammals.

Please refer to the information given previously (Description of Sound Sources) regarding sound, characteristics of sound types, and metrics used in this document. Anthropogenic sounds cover a broad range of frequencies and sound levels and can have a range of highly variable impacts on marine life, from none or minor to potentially severe responses, depending on received levels, duration of exposure, behavioral context, and various other factors. The potential effects of underwater sound form active acoustic sources can potentially result in one or more of the following: Temporary or permanent hearing impairment, non-auditory physical or physiological effects, behavioral disturbance, stress, and masking (Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 2007; Southall et al., 2007; Gotz et al., 2009). The effects of pile driving on marine mammals are dependent on several factors, including the size, type, and depth of the animal; the depth, intensity, and duration of the pile driving sound; the depth of the water column; the substrate of the habitat; the standoff distance between the pile and the animal; and the sound propagation properties of the environment. Impacts to marine mammals from pile driving activities are expected to result primarily from acoustic pathways. As such, the degree of effect is intrinsically related to the received level and duration of the sound exposure, which are in turn influenced by the distance between the animal and the source. The further away from the source, the less intense the exposure should be. The substrate and depth of the habitat affect the sound propagation properties of the environment. Shallow environments are typically more structurally complex, which leads to rapid sound attenuation. In addition, substrates that are soft (e.g., sand) would absorb or attenuate the sound more readily than hard substrates (e.g., rock) which may reflect the acoustic wave. Soft porous substrates would also likely require less time to drive the pile, and possibly less forceful equipment, which would ultimately decrease the intensity of the acoustic source.

In the absence of mitigation, impacts to marine species would be expected to result from physiological and behavioral responses to both the type and strength of the acoustic signature (Viada et al., 2008). The type and severity of behavioral impacts are more difficult to define due to limited studies addressing the behavioral effects of impulse sounds on marine mammals. Potential effects from impulse sound sources can range in severity from effects such as behavioral disturbance or tactile perception to physical discomfort, slight injury of the internal organs and the auditory system, or mortality (Yelverton et al., 1973).

Hearing Impairment and Other Physical Effects—Marine mammals exposed to high intensity sound repeatedly or for prolonged periods can experience hearing threshold shift (TS), which is the loss of hearing sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt et al., 2000; Finneran et al., 2002, 2005). TS can be permanent (PTS) in which case the loss of hearing sensitivity is not recoverable, or temporary (TTS), in which the animal's hearing threshold would recover over time (Southall et al., 2007). Marine mammals depend on acoustic cues for vital biological functions (e.g., orientation, communication, foraging, avoiding predators); thus, TTS may result in reduced fitness in survival and reproduction. However, this depends on the frequency and duration of TTS, as well as the biological context in which it occurs. TTS of limited duration, occurring in a frequency range that does not coincide with that used for recognition of important acoustic cues, would have little to no effect on an animal's fitness. Repeated sound exposure that leads to TTS could cause PTS. PTS constitutes injury, but TTS does not (Southall et al., 2007). The following subsections discuss in somewhat more detail the possibilities of TTS, PTS, and non-auditory physical effects.

Temporary Threshold Shift—TTS is the mildest form of hearing impairment that can occur during exposure to a strong sound (Kryter 1985). While experiencing TTS, the hearing threshold rises, and a sound must be stronger in order to be heard. In terrestrial mammals, TTS can last from minutes or hours to days (in cases of strong TTS). For sound exposures at or somewhat above the TTS threshold, hearing sensitivity in both terrestrial and marine mammals recovers rapidly after exposure to the sound ends. Few data on sound levels necessary to elicit mild TTS have been obtained for marine mammals, and none of the published data concern TTS elicited by exposure to multiple pulses of sound. Available data on TTS in marine mammals are summarized in Southall et al. (2007).

Permanent Threshold Shift—When PTS occurs, there is physical damage to the sound receptors in the ear. In severe cases, there can be total or partial deafness, while in other cases the animal has an impaired ability to hear sounds in specific frequency ranges (Kryter 1985). There is no specific evidence that exposure to pulses of sound can call PTS in any marine mammal. However, given the possibility that mammals close to a sound source might incur TTS, there has been further speculation about the possibility that some individuals might incur PTS. Single or occasional occurrences of mild TTS are not indicative of permanent auditory damage but repeated (or in some cases) single exposures to a level well above that causing TTS onset might elicit PTS.

Relationships between TTS and PTS thresholds have not been studied in marine mammals—PTS data exists only for a single harbor seal (Kastak et al., 2008)—but are assumed to be similar to those in humans and other terrestrial mammals. PTS might occur at a received sound level at least several decibels above that inducing mild TTS if the animal were exposed to strong sound pulses with rapid rise time. Based on data from terrestrial mammals, a precautionary assumption is that the PTS threshold for impulse sounds (such as pile driving pulses received close to the source) is at least 6 dB higher than the TTS threshold on a peak-pressure basis and PTS cumulative sound exposure level threshold are 15 to 20 dB higher than TTS cumulative sound exposure level thresholds (Southall et al., 2007). 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. The City will enforce a Level A exclusion zone to prevent PTS for all activities (see Proposed Mitigation section below).

Non-auditory Physiological Effects—Non-auditory physiological effects or injuries that might theoretically occur in marine mammals exposed to strong underwater sound include stress, neurological effects, bubble formation, resonance effects, and other types of organ or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies examining such effects are limited. In general, little is known about the potential for pile driving to cause auditory impairment or other physical effects in marine mammals. Available data suggest that such effects, if they occur at all, would presumably be limited to short distances from the sound source and to activities that extend over a prolonged period. The available data do not allow identification of a specific exposure level above which non-auditory effects can be expected (Southall et al., 2007) or any meaningful quantitative predictions of the numbers (if any) of marine mammals that might be affected in those ways. However, the proposed activities do not involve the use of devices such as explosives or mid-frequency active sonar that are associated with these types of effects. Therefore, non-auditory physiological impacts to marine mammals are considered unlikely.

Disturbance includes a variety of effects, including subtle changes in behavior, more conspicuous changes in activities, and displacement. Behavioral responses to sound are highly variable and context-specific and reactions, if any, depend on species, state of maturity, experience, current activity, reproductive state, auditory sensitivity, time of day, and many other factors (Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007).

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., 2003). Animals are most likely to habituate to sounds that are predictable and unvarying. 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. Behavioral state may affect the type of response as well. 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; NRC 2003; Wartzok et al., 2003).

Controlled experiments with captive marine mammals showed pronounced behavioral reactions, including avoidance of loud sound sources (Ridgeway et al., 1997; Finneran et al., 2003). Responses to continuous sound, such as vibratory pile installation, have not been documented as well as responses to pulsed sounds.

With vibratory pile driving (and removal, as in this project), it is likely that the onset of pile driving could result in temporary, short term changes in an animal's typical behavior and/or avoidance of the affected area. These behavioral changes may include (Richardson et al., 1995): Changing durations of surfacing and dives; moving direction and/or speed; reduced/increased vocal activities; changing/cessation of certain behavioral activities (such as socializing or feeding); visible startle response or aggressive behavior; avoidance of areas where sound sources are located; and/or flight responses (e.g., pinnipeds flushing into the water from haul-outs or rookeries). Pinnipeds may also increase their haul-out time, possibly to avoid in-water disturbance (Thorson and Reyff, 2006).

The biological significance of many of these behavioral disturbances is difficult to predict, especially if the detected disturbances appear minor. However, the consequences of behavioral modification could be expected to be biologically significant if the change affects growth, survival, or reproduction. Significant behavioral modifications that could potentially lead to effects on growth, survival, or reproduction include:

• Drastic changes in diving/surfacing patterns;

• Habitat abandonment due to loss of desirable acoustic environment; and

• Cessation of feeding or social interaction.

The onset of behavioral disturbances from anthropogenic sound depends on both external factors (characteristics of sound sources and their paths) and the specific characteristics of the receiving animals (hearing, motivation, experience, demography) and is difficult to predict (Southall et al., 2007).

Natural and artificial sounds can disrupt behavior by masking, or interfering with, a marine mammal's ability to hear other sounds. Masking occurs when the receipt of a sound is interfered with by another coincident sound at similar frequencies and at similar or higher levels. Chronic exposure to excessive, though not high-intensity, sound could cause masking at particular frequencies for marine mammals which utilize sound for vital biological functions. Masking can interfere with detection of acoustic signals such as communication calls, echolocation sounds, and environmental sounds important to marine mammals. 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. If the coincident (masking) sound were man-made, it could potentially be harassing if it disrupted hearing-related behavior. It is important to distinguish TTS and PTS, which persist after the sound exposure, from masking, which occurs only 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.

The frequency range of the potentially masking sound is important in determining any potential behavioral impacts. Because sound generated from in-water vibratory pile driving is mostly concentrated at low frequency ranges, it may have less effect on high frequency echolocation sounds by odontocetes, which may hunt harbor seals. However, lower frequency man-made sounds are more likely to affect detection of communication calls and other potentially important natural sounds such as surf and prey sound. It may also affect communication signals when they occur near the sound band and thus reduce the communication space of animals (e.g., Clark et al., 2009) and cause increased stress levels (e.g., Foote et al., 2004; Holt et al., 2009).

Masking affects both senders and receivers of acoustic signals and can potentially have long-term chronic effects on marine mammals at the population level as well as the individual level. Low-frequency ambient sound levels have increased by as much as 20 dB (more than three times in terms of SPL) in the world's ocean from pre-industrial periods, with most of the increase from distant commercial shipping (Hildebrand 2009). All anthropogenic sound sources, but especially chronic and lower-frequency signals (e.g., from vessel traffic), contribute to elevated ambient sound levels, thus intensifying masking.

Vibratory pile removal is relatively short-term, with rapid oscillations occurring for approximately 30 minutes per pile. It is possible that the vibratory pile removal resulting from this proposed action may mask acoustic signals important to the behavior and survival of marine mammal species, but the short-term duration and limited affected area would result in insignificant impacts from masking. Any masking event that could possibly rise to Level B harassment under the MMPA would occur concurrently within the zones of behavioral harassment already estimated for vibratory pile driving, and which have already been taken into account in the exposure analysis.

Acoustic Effects, Airborne—Marine mammals, specifically California sea lions, that occur in the project area could be exposed to airborne sounds associated with pile driving and other construction activities (e.g., concrete removal) that have the potential to cause harassment, depending on their distance from pile driving activities. Airborne construction sounds may be an issue for pinnipeds either hauled-out or looking with heads above water in the project area. 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 their habitat and move further from the source. Studies by Blackwell et al. (2002) and Moulton et al. (2005) indicate a tolerance or lack of response to unweighted airborne sounds as high as 112 dB peak and 96 dB rms.

Visual Disturbance—While three species of pinnipeds occur in the project area, only California sea lions are known to haul out in the vicinity of the bridges. California sea lions hauled out on the riverbanks below the bridge crossings and rail trestle may be visually disturbed by the increased presence of humans and construction equipment. Much of the work will occur above the riverbanks but some work will occur on the shore (e.g., concrete footing removal) in the vicinity of California sea lions. Sea lions may flush from their haul out site if construction equipment (e.g., excavator, crane, concrete saw) or personnel are present. General construction work associated with the demolition and installation of roadway and railway superstructures has the potential to visually disturb California sea lions.

The primary potential effects to marine mammal habitat are associated with elevated sound levels produced by construction activities (e.g., pile driving, concrete removal) in the area. However, other potential impacts to the surrounding habitat from physical disturbance are also possible.

Potential Pile Driving Effects on Prey—Construction activities would produce continuous (i.e., vibratory pile driving) and impulsive (i.e., impact pile driving) sounds. Fish react to sounds that are especially strong and/or intermittent low-frequency sounds. Short duration, sharp sounds can cause overt or subtle changes in fish behavior and local distribution. 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 fish, although several are based on studies in support of large, multiyear bridge construction projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound pulses at received levels of 160 dB may cause subtle changes in fish behavior. SPLs of 180 dB may cause noticeable changes in behavior (Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient strength have been known to cause injury to fish and fish mortality. The most likely impact to fish from pile driving activities at the project area would be temporary behavioral avoidance of the area. The duration of fish avoidance of this area after pile driving stops is unknown, but a rapid return to normal recruitment, distribution, and behavior is anticipated. In general, impacts to marine mammal prey species are expected to be minor and temporary due to the short timeframe for the project.

Effects to Foraging Habitat—Pile installation and removal may temporarily increase turbidity resulting from suspended sediments. Any increases would be temporary, localized, and minimal. The City of Astoria must comply with state water quality standards during these operations by limiting the extent of turbidity to the immediate project area. In general, turbidity associated with pile installation is localized to about a 25-ft (7.62 m) radius around the pile (Everitt et al., 1980). Natural tidal currents and flow patterns in the Columbia River routinely disturb sediments. High volume tidal events can result in hydraulic forces that re-suspend benthic sediments, temporarily elevating turbidity locally. Any temporary increase as a result of the proposed action is not anticipated to measurably exceed levels caused by these normal, natural periods.

In summary, given the short daily duration of sound associated with individual pile driving and removal events and the relatively small areas being affected, the proposed activities are not likely to have a permanent adverse effect on any fish habitat, or populations of fish species. Thus, any impacts to marine mammal habitat are not expected to cause significant or long-term consequences for individual marine mammals or their populations.

This section provides an estimate of the number of incidental takes proposed for authorization through this IHA, which will inform both NMFS' consideration of whether the number of takes is “small” and the negligible impact determination.

Harassment is the only type of take expected to result from these activities. Except with respect to certain activities not pertinent here, section 3(18) of the MMPA defines “harassment” as: Any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

Authorized takes would be by Level B harassment only, for individual marine mammals resulting from exposure to pile driving and construction activities. Based on the nature of the activity and the anticipated effectiveness of the mitigation measures (i.e., shutdown— discussed in detail below in Proposed Mitigation section), Level A harassment is neither anticipated nor proposed to be authorized.

As described previously, no mortality is anticipated or proposed to be authorized for this activity. Below we describe how the take is estimated.

Described in the most basic way, we estimate take by considering: (1) Acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be behaviorally harassed or incur some degree of permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and, (4) and the number of days of activities. Below, we describe these components in more detail and present the proposed take estimate.

Using the best available science, NMFS has developed acoustic thresholds that identify the received level of underwater sound above which exposed marine mammals would be reasonably expected to be behaviorally harassed (equated to Level B harassment) or to incur PTS of some degree (equated to Level A harassment). Thresholds have also been developed identifying the received level of in-air sound above which exposed pinnipeds would likely be behaviorally harassed.

Level B Harassment for non-explosive sources—Though significantly driven by received level, the onset of behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source (e.g., frequency, predictability, duty cycle), the environment (e.g., bathymetry), and the receiving animals (hearing, motivation, experience, demography, behavioral context) and can be difficult to predict (Southall et al., 2007, Ellison et al., 2011). Based on what the available science indicates and the practical need to use a threshold based on a factor that is both predictable and measurable for most activities, NMFS uses a generalized acoustic threshold based on received level to estimate the onset of behavioral harassment. NMFS predicts that marine mammals are likely to be behaviorally harassed in a manner we consider Level B harassment when exposed to underwater anthropogenic noise above received levels of 120 dB re 1 μPa (rms) for continuous (e.g. vibratory pile-driving, drilling) and above 160 dB re 1 μPa (rms) for non-explosive impulsive (e.g., seismic airguns) or intermittent (e.g., scientific sonar) sources. For in-air sounds, NMFS predicts that pinnipeds exposed above received levels of 100 dB re 20 μPa (rms) will be behaviorally harassed.

The City's proposed activities include the use of continuous (vibratory pile driving) and impulsive (impact pile driving) sources, and therefore the 120 and 160 dB re 1 μPa (rms) are applicable.

Level A harassment for non-explosive sources—NMFS' Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Technical Guidance, 2016) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). The City's proposed activities include the use of impulsive (impact pile driving) and non-impulsive (vibratory pile driving) sources.

These thresholds were developed by compiling and synthesizing the best available science and soliciting input multiple times from both the public and peer reviewers to inform the final product, and are provided in Table 6 below. The references, analysis, and methodology used in the development of the thresholds are described in NMFS 2016 Technical Guidance, which may be accessed at: https://www.fisheries.noaa.gov/resource/document/underwater-acoustic-thresholds-onset-permanent-and-temporary-threshold-shifts.

Here, we describe operational and environmental parameters of the activity that will feed into identifying the area ensonified above the acoustic thresholds.

In-Air Disturbance during General Construction Activities—Level B behavioral disturbance may occur incidental to the use of construction equipment during general construction that is proposed in the dry, above water, or inland within close proximity to the river banks. These construction activities are associated with the removal and construction of the rail superstructures, and the removal of the existing concrete foundations and the 9th Street retaining wall. Possible equipment includes an excavator, crane, dump truck, and chain saw. It is estimated that the sound levels during these activities will range from 78 to 93 dB RMS at 20 m from the sound source, with the loudest airborne noise produced by the use of a concrete saw (Hanan & Associates, 2014). These noise levels are based on acoustic data collected during the City of San Diego Lifeguard Station Demolition and Construction Monitoring project. Using the Spherical Spreading Loss Model (20logR), a maximum sound source level of 93 dB RMS at 20 m, sound levels in-air would attenuate below the 90dB RMS Level B harassment threshold for harbor seals at 28 m, and below the 100 dB RMS threshold for all other pinnipeds at 9 m. Harbor seals are only present in the main river channel and are not expected to occur within 28 m of the activity and are therefore not expected to be harassed by in-air sound. Additionally, the city is proposing a 10 m shutdown zone for all general construction work to prevent injury from physical interaction with equipment. The City would therefore shut down equipment before hauled out sea lions could be acoustically harassed by the sound produced. No Level B harassment is expected to occur due to increased sounds from railway and roadway construction. However, sea lions may be disturbed by the presence of construction equipment and increased human presence during above-water construction.

Although some piles may potentially be driven or removed in the dry due to tidal conditions, the City is assuming all pile driving and removal will occur in water. The Level B zone of influence for in-water pile driving and removal is greater than the airborne zone of influence so no airborne harassment is requested from pile driving or removal. All harassment due to pile driving and removal is assumed to be in-water.

In-Water Disturbance during Vibratory Pile Removal—Level B behavioral disturbance may occur incidental to the use of a vibratory hammer due to propagation of underwater noise during the removal of the existing timber substructures. An estimated 255 timber piles will need to be removed to facilitate construction of the three new crossings. It is anticipated that the contractor will need to utilize a vibratory hammer during extraction. Removal via vibratory hammer will result in the greatest amount of underwater noise during construction and will be the farthest reaching extent of aquatic impacts during pile removal activities. We note that some pile removal will occur in the dry (depending on tidal stage); however, we are conservatively assuming all work would occur in-water since it is not feasible to determine how many piles would be removed in the dry. When piles are removed at lower tidal stages, we do not anticipate sound to propagate as far or, in the case of no water, at all.

Washington State Department of Transportation (WSDOT) monitored underwater noise during the removal of three 12-in timber dolphin piles at Port Townsend (Laughlin, 2011a). Most of the timber piles to be removed in this project are 12-in but some may be up to 14-in. Average noise levels during vibratory removal of the wood piles were measured at 150 dB RMS at 16 m from the source. The Practical Spreading Loss Model (15logR) was used to calculate the in-water Level B Zone of Influence (ZOI) during vibratory pile removal. Using a measurement of 150dB at 16 m, a 1,600 m Level B ZOI (120 dB RMS threshold) is expected for vibratory pile removal activities. Based on the contours of the shoreline and 1,600 m ZOI, a total of 4.5 square kilometers (km2) is expected to be ensonified due to vibratory pile removal (see Figure 10 in application) (Table 7).

In-Water Disturbance during Impact Pile Driving—Level B behavioral disturbance may occur incidental to the use of an impact hammer due to the propagation of underwater noise during the installation of permanent and temporary steel piles. The City proposes to install a total of 74 24-in and 10 16-in steel piles. The City used the sound source levels from 24-in piles only to estimate the ZOI due to pile driving as the sound source levels from 24-in piles are greater than those of 16-in piles. The City will use the ZOI created by installation of 24-in piles during the installation of 16-in piles to be conservative.

Based on the most recent WSDOT data, the unmitigated sound pressure level associated with impact pile driving 24-in steel piles is 194 dB RMS at 10 m (WSDOT, 2016). The contractor will be required to use a bubble curtain device during impact pile driving in compliance with the Federal Aid Highway Program (FAHP) Programmatic Biological Opinion which will be utilized for ESA coverage for listed salmonids. Use of a bubble curtain device was assumed to decrease initial sound levels by 10 dB (Reyff 2007), resulting in an initial SPL of 184 dB RMS at 10 m from the source. Using the values from WSDOT in the Practical Spreading Loss Model (15logR), the distance to the 160 dB behavioral disturbance threshold is calculated to be 398 m from the pile when a noise attenuation device is used (Table 7) as opposed to 1,848 m when a device is not used. The use of a noise attenuation device would shrink the distance at which noise exceeds the thresholds by approximately 80 percent, resulting in a significantly smaller area of potential impact. With a 398 m ZOI, a total of 0.40 km2 is expected to be ensonified by impact pile driving (Figure 11 in application).

When NMFS Technical Guidance (2016) was published, in recognition of the fact that ensonified area/volume could be more technically challenging to predict because of the duration component in the new thresholds, we developed a User Spreadsheet that includes tools to help predict a simple isopleth that can be used in conjunction with marine mammal density or occurrence to help predict takes. We note that because of some of the assumptions included in the methods used for these tools, we anticipate that isopleths produced are typically going to be overestimates of some degree, which will result in some degree of overestimate of Level A take. However, these tools offer the best way to predict appropriate isopleths when more sophisticated 3D modeling methods are not available, and NMFS continues to develop ways to quantitatively refine these tools, and will qualitatively address the output where appropriate. For stationary sources (such as impact and vibratory pile driving), NMFS User Spreadsheet predicts the closest distance at which, if a marine mammal remained at that distance the whole duration of the activity, it would not incur PTS. Inputs used in the User Spreadsheet, and the resulting isopleths are reported below.

The resulting small PTS isopleths assume an animal would remain stationary at that distance for the duration of the activity. Given the extended durations and due to the relatively small distances to PTS onset from each activity, and the mitigation measures (See “Proposed Mitigation”) proposed by the City, Level A take is neither expected nor authorized.

In this section we provide the information about the presence, density, or group dynamics of marine mammals that will inform the take calculations.

The City used species counts from 2000-2014 taken by WDFW from the South Jetty at the mouth of the Columbia River to determine the number of pinnipeds that may be in the vicinity of the project. Although the South Jetty is over 10 miles away from the project site, WDFW monthly counts are the best available data for potential marine mammal occurrence near the project site. Numbers of California sea lions hauled out at the South Jetty ranged from 1 to 1,214, with a general trend of lower numbers in the summer and winter, and peak counts in the fall and spring. Monthly counts of Steller sea lions ranged from 177 to 1,663, with the highest numbers occurring in late fall and winter. Counts of harbor seals were not conducted every month, but the numbers of harbor seals at the South Jetty ranged from one to 57 seals.

Here we describe how the information provided above is brought together to produce a quantitative take estimate.

Although three species of pinniped occur in the vicinity of the project, they do not occur in equal numbers. Harbor seals and Steller sea lions are only known to occur out in the river channel and would only be harassed if they are transiting through the Zone of Influence (1,600 m for vibratory pile removal, 398 m for impact pile driving). Harbor seals and Steller sea lions would only be harassed during the in-water work period (November through February). California sea lions are the most commonly seen in the area, and are known to haul out on the riverbanks and structures near the bridges. California sea lions may be harassed by underwater sound resulting from vibratory pile removal and impact pile driving (at the distances listed above) as well as airborne sound resulting from roadway and railway demolition and construction. Using the highest sound source (concrete saw, 93 dBRMS re: 20 µPa at 20 m), the isopleth to Level B harassment from airborne noise (100 dB re: 20 µPa) is 9 m. The City is proposing a 10 m shutdown zone during all railway and roadway above-water construction to prevent injury from physical interaction with equipment (see “Proposed Mitigation”). The City would therefore shut down equipment before sea lions would be acoustically harassed by the sound produced and no Level B acoustic harassment would occur. However, the City anticipates that California sea lions hauled out on the banks of the river in the vicinity of the construction work may be visually disturbed by the presence of construction equipment and may flush, resulting in Level B take. Therefore, the City is requesting take of California sea lions during the above-water work period (October 2018 and March-April 2019).

While harbor seals and Steller sea lions would only be harassed during the in-water work period (November through February), California sea lions may be harassed over the entire duration of the project (October through April). To determine the estimated pinniped exposure and take, average monthly counts for each species from the South Jetty haulout (Table 12) were multiplied by the duration (months) of their expected exposure (Table 13).

For example, California sea lion take was estimated by multiplying the average monthly count at the South Jetty haulout from October through April (372) by the number of months of project activity (7) for a total of 2,604.

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.

An incidental take authorization shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth.

NMFS has defined “negligible impact” in 50 CFR 216.103 as an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.

The MMPA states that the term “take” means to harass, hunt, capture, kill or attempt to harass, hunt, capture, or kill any marine mammal.

Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as any act of pursuit, torment, or annoyance, which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

On February 6, 2018, NMFS received an adequate and complete application from the NPS requesting authorization for take of marine mammals incidental to glaucous-winged gull and climate monitoring research activities in GLBA NP, Alaska. The requested regulations would be valid for five years, from March 2019 through December 2023. The NPS plans to conduct necessary work, including gull and climate monitoring to assist in informing future native egg harvests and fill crucial climate data gaps. The proposed action may incidentally expose marine mammals occurring in the vicinity to either acoustic disturbance from motorboat sounds or visual disturbance from the presence of observers, thereby resulting in incidental take, by Level B harassment only. Therefore, the NPS requests authorization to incidentally take eastern pacific harbor seals.

The purpose for the monitoring activities are as follows. Gull monitoring studies are mandated by a Record of Decision of a Legislative Environmental Impact Statement (LEIS) (NPS 2010) which states that NPS must initiate a monitoring program for glaucous-winged gulls (Larus glaucescens) to inform future native egg harvest by the Hoonah Tlingit in Glacier Bay, Alaska. Installation of a new weather station on Lone Island is being planned as one of several installations intended to fill coverage gaps among existing weather stations in GLBA NP (NPS 2015a). These new stations will be operated as the foundation of a new long-term climate-monitoring program for GLBA NP. The maximum number of days the NPS will conduct annual monitoring activities that require a Letter of Authorization will be 24 days during each of the five years of work. This consists of four possible yearly climate monitoring visits to Lone Island during the months of October to April and five possible annual gull monitoring visits each to Boulder Island, Geikie Rock, Lone Island and Flapjack Island during the months of May to September. Eastern Pacific harbor (Phoca vitulina richardii) seals are the only marine mammals expected to be taken by the activities as the NPS will maintain a distance of 100 meters from all Steller sea lions.

Interested persons may submit information, suggestions, and comments concerning the NPS' request (see ADDRESSES). NMFS will consider all information, suggestions, and comments related to the request during the development of proposed regulations governing the incidental taking of marine mammals by the NPS, if appropriate.

The Department of Education (ED), in accordance with the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3506(c)(2)(A)), provides the general public and Federal agencies with an opportunity to comment on proposed, revised, and continuing collections of information. This helps the Department assess the impact of its information collection requirements and minimize the public's reporting burden. It also helps the public understand the Department's information collection requirements and provide the requested data in the desired format. ED is soliciting comments on the proposed information collection request (ICR) that is described below. The Department of Education is especially interested in public comment addressing the following issues: (1) Is this collection necessary to the proper functions of the Department; (2) will this information be processed and used in a timely manner; (3) is the estimate of burden accurate; (4) how might the Department enhance the quality, utility, and clarity of the information to be collected; and (5) how might the Department minimize the burden of this collection on the respondents, including through the use of information technology. Please note that written comments received in response to this notice will be considered public records.

Title of Collection: Migrant Student Information Exchange User Application Form.

OMB Control Number: 1810-0686.

Type of Review: An extension of an existing information collection.

Respondents/Affected Public: State, Local, and Tribal Governments.

Total Estimated Number of Annual Responses: 420.

Total Estimated Number of Annual Burden Hours: 210.

Abstract: The Department requests to extend the collection of the existing MSIX User Application. State educational agencies (SEAs) with MEPs will collect the information from state and local education officials who desire access to the MSIX system. The collection instrument verifies the applicant's need for MSIX data and authorizes the user's access to that data. The burden hours associated with the data collection are required to meet the statutory mandate in Sec. 1308(b) of Elementary and Secondary Education Act (ESEA), as amended by the Every Student Succeeds Act, which is to facilitate the electronic exchange by the SEAs of a set of minimum data elements to address the educational and related needs of migratory children.

The Department of Education (ED), in accordance with the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3506(c)(2)(A)), provides the general public and Federal agencies with an opportunity to comment on proposed, revised, and continuing collections of information. This helps the Department assess the impact of its information collection requirements and minimize the public's reporting burden. It also helps the public understand the Department's information collection requirements and provide the requested data in the desired format. ED is soliciting comments on the proposed information collection request (ICR) that is described below. The Department of Education is especially interested in public comment addressing the following issues: (1) Is this collection necessary to the proper functions of the Department; (2) will this information be processed and used in a timely manner; (3) is the estimate of burden accurate; (4) how might the Department enhance the quality, utility, and clarity of the information to be collected; and (5) how might the Department minimize the burden of this collection on the respondents, including through the use of information technology. Please note that written comments received in response to this notice will be considered public records.

Title of Collection: Program for International Student Assessment (PISA 2018) Main Study.

OMB Control Number: 1850-0755.

Type of Review: A revision of an existing information collection.

Respondents/Affected Public: Individuals or Households.

Total Estimated Number of Annual Responses: 57,878.

Total Estimated Number of Annual Burden Hours: 22,604.

Abstract: The Program for International Student Assessments (PISA) is an international assessment of 15-year-olds which focuses on assessing students' reading, mathematics, and science literacy. PISA was first administered in 2000 and is conducted every three years. The United States has participated in all of the previous cycles, and is participating in 2018 in order to track trends and to compare the performance of U.S. students with that of students in other education systems. PISA 2018 is sponsored by the Organization for Economic Cooperation and Development (OECD). In the United States, PISA is conducted by the National Center for Education Statistics (NCES), within the U.S. Department of Education. In each administration of PISA, one of the subject areas (reading, mathematics, or science literacy) is the major domain and has the broadest content coverage, while the other two subjects are the minor domains. PISA emphasizes functional skills that students have acquired as they near the end of mandatory schooling (aged 15 years), and students' knowledge and skills gained both in and out of school environments. PISA 2018 will focus on reading literacy as the major domain. Mathematics and science literacy will also be assessed as minor domains, with additional assessment of financial literacy. In addition to the cognitive assessments described above, PISA 2018 will include questionnaires administered to assessed students, school principals, and teachers. The PISA 2018 Recruitment and Field Test were approved in September 2016 with the latest change request approved in September 2017 (1850-0755 v.18-20). The PISA 2018 field test was conducted in March-May 2017. The PISA 2018 main study recruitment began in October 2017 and data collection will be conducted October-November 2018. This request provides the final plans, burden, and materials for PISA 2018 main study.

Background: On January 24, 2018, we published in the Federal Register (83 FR 3335) a notice of a call for written third-party comments with respect to accrediting agencies currently undergoing review for purposes of recognition by the Secretary of Education. Under that notice, the public comment period closes on February 16, 2018. On February 15, 2018, the U.S. District Court for the Southern District of New York ordered the Department of Education to extend the comment period to March 1, 2018, for comments on the initial application for recognition of ACICS and the compliance report submitted by the ABA. (See The Century Foundation v. Betsy Devos, case number 18-cv-1128).

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