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Federal Register / Vol. 86, No. 86 / Thursday, May 6, 2021 / Rules and Regulations TABLE 5LEVEL A AND LEVEL B HARASSMENT ISOPLETHSContinued Site
Level A harassment isopleth m
Pile size and type LF cetacean
Craney Island
Lamberts Point
1 Please
I

MF cetacean
16-in Composite/12-in Timber
I

HF cetacean
I

Phocid
Level B
harassment isopleth m 1

<10m
3,001
7,161

refer to Tables 65 and 66 in the Navys application for the areas of the Level B harassment zones.

Marine Mammal Occurrence and Take Calculation and Estimation In this section we provide the information about the presence, density, or group dynamics of marine mammals that will inform the take calculations.
We describe how the information provided above is brought together to produce a quantitative take estimate.
Humpback Whale Humpback whales occur in the mouth of the Chesapeake Bay and nearshore waters of Virginia during winter and spring months. Most detections during shipboard surveys were of one or two juveniles per sighting. Although two individuals were detected in the vicinity of MPU project activities, there is no evidence that they linger for multiple days. Because no density estimates are available for the species in this area, the Navy estimated one take for every 60 days of pile driving.
However, given the potential group size of two, as indicated by the sightings referenced above, NMFS has estimated that two humpback whales may be taken by Level B harassment for every 60 days of pile driving. Therefore, given the number of project days expected in
each year Table 4, NMFS may authorize a total of 24 takes by Level B
harassment of humpback whale over the five-year authorization, with no more than eight takes by Level B harassment in one year.
The largest Level A harassment zone for low-frequency cetaceans extends approximately 52 m from the source during impact pile driving of 24-in concrete piles at the MWR Marina Table 5. For most activities, the Level A harassment zone is less than 20 m.
The Navy is planning to implement a 55-m shutdown zone for humpback whales during impact pile driving of 24in concrete piles, and shutdown zones that include the entire Level A
harassment isopleth for all activities, as indicated in Table 11. Therefore, the Navy did not request, and NMFS will not authorize Level A harassment take of humpback whale.
Bottlenose Dolphin The expected number of bottlenose dolphins in the project area was estimated using inshore seasonal densities provided in Engelhaupt et al.
2016 from vessel line-transect surveys near NAVSTA Norfolk and adjacent
areas near Virginia Beach, Virginia, from August 2012 through August 2015
Engelhaupt et al. 2016. To calculate Level B harassment takes of bottlenose dolphin, NMFS used the Chesapeake Bay density of 1.38 dolphins/km2
Engelhaupt et al. 2016. This density includes sightings inshore of the Chesapeake Bay from NAVSTA Norfolk west to the Thimble Shoals Bridge, and is the most representative density for the project area. NMFS conservatively multiplied the density of 1.38 dolphins/
km2 by the largest Level B harassment zone for each project location Table 7
and then by the proportional number of estimated pile driving days at each location for each year Table 6. For example, to calculate Level B
harassment takes associated with work at Pier 3 in 2021, NMFS multiplied the density 1.38 dolphins/km2 by largest Level B harassment zone for Pier 3 10.3
km2 by the proportional number of pile driving days at Pier 3 in 2021 24.6 for a total of 350 Level B harassment takes at Pier 3 in 2021. Therefore, NMFS may authorize 7,566 takes by Level B
harassment of bottlenose dolphin across all five years, with no more than 2,742
in one year.

TABLE 6ESTIMATED NUMBER OF PILE DRIVING DAYS AT EACH PROJECT LOCATION
Estimated number of pile driving days all seasons
khammond on DSKJM1Z7X2PROD with RULES

Location 1

Proportional number of pile driving days 3
2021

2022

2023

2024

2025

Pier 3
Pier 12
MWR Marina
V-Area
Craney Island
Lamberts Point

68
352
52
44
52
8

24.6
127.6
18.8
15.9
18.8
2.9

10.0
51.5
7.6
6.4
7.6
1.2

2.1
11.0
1.6
1.4
1.6
0.3

9.0
46.6
6.9
5.8
6.9
1.1

22.3
115.3
17.0
14.4
17.0
2.6

Estimated Total Pile Driving Days per Year

2 574

208

84

18

76

188

Percentage of Total Pile Driving Days

36

15

3

13

33

1 While the Navy plans to conduct work at additional locations not listed here, these locations are assumed to be representative of the overall project site ex: all pile driving lumped together at Lamberts Point Deperming Station, as noted in Appendix A of the Navys application. Pile driving at these additional locations is included in the total number of pile driving days assumed here.
2 NMFS recognizes that due to rounding, the sum of the estimated number of work days at each location is 576, not 574. However, as mentioned previously, the Navy expects construction to last 574 days across all five years.
3 The number of pile driving days indicated per year at each location is intended to inform our assessment of both the total and maximum annual taking allowable under the rule. NMFS does not expect that the Navy will conduct exactly the fractional number of days of pile driving indicated for each year in each location.

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