Je veux savoir à propos de…

tkelley on DSKBCP9HB2PROD with NOTICES2

Federal Register / Vol. 86, No. 33 / Monday, February 22, 2021 / Notices in the biological opinion, including a shutdown zone of 215 m for screeding.
NMFS has added this specific requirement to the final IHA as well.
Gravel deposition will produce a continuous sound of a relatively short duration, does not require seafloor penetration, and will affect a very small portion of habitat for marine mammals and their prey. Therefore, NMFS does not expect gravel deposition to result in marine mammal harassment. Further, a portion of the gravel deposition will occur behind sheet piles, which will act as an acoustic barrier which further supports the conclusion that take from gravel deposition is unlikely to occur.
Regarding the planned multi-beam hydrographic surveys, which AGDC will perform to identify high and low spots in the seabed prior to each season, the survey would be conducted with equipment emitting sound above 200
kiloHertz kHz, which as described in the Marine Mammal Hearing section of the notice of the proposed IHA 85 FR
43382; July 16, 2020, is above the highest frequency in the generalized hearing ranges of marine mammals 35
kHz for LF cetaceans, 160 kHz for MF
and HF cetaceans, 86 kHz for phocids, and 39 kHz for otariids. We do not expect these surveys to take marine mammals, as marine mammals are unlikely to hear the surveys, much less respond to them. The stranding events in Madagascar and the Gulf of California described in Comment 12, below involved different sources from that which AGDC plans to use, and in those events, the sources were within marine mammal hearing ranges.
NMFS included the barge bridge tail wall piles to be installed in-water in its analysis. A large portion of the barge bridge tail wall piles will be driven into dry ground, and therefore installation is unlikely to result in take of marine mammals. Please see Comment 16 for information about why NMFS does not expect take from in-air noise such as pile driving on land.
Construction of the seabed pad includes drilling or augering holes through the sea ice, an initial throughice bathymetric survey, and smoothing of the seabed including potential gravel fill and installation of rock-filled marine mattresses is not predicted to result in the take of marine mammals for the reasons described below.
Drilling/augering and the through-ice bathymetric survey are the first steps of the seabed pad preparation, which is expected to begin in February.
Cetaceans are not predicted to be present in the area during this time Quakenbush et al., 2018, Citta et al., 2016 and while ringed seals likely will
VerDate Sep<11>2014

20:43 Feb 19, 2021

Jkt 253001

be present, few, if any, spotted or bearded seals are likely to be present during that time Bengston et al., 2005;
Lowry et al., 1998; Simpkins et al., 2003. Therefore, take of cetaceans from drilling/augering is not expected, and take of spotted or bearded seals is so low as to be discountable. Given that drilling/augering is expected to occur in February, prior to ringed seals establishing lairs, we would not expect ringed seals to build their lairs close enough to the project so as to be disturbed by the drilling/augering activity. The potential that a seal might be disturbed by the activity and build its lair in an alternate location due to drilling/augering is accounted for in the Level B harassment takes, which have considered all likely take by behavioral disturbance, including that which could influence lair location.
Smoothing of seabed screeding is unlikely to result in take, and NMFS has included a shutdown zone for screeding, as described above. Gravel deposition is not expected to take marine mammals for the reasons described above. While placement of rock-filled mattresses could result in take due to the physical presence of the equipment and mattresses, the likelihood of marine mammals being close enough to this activity to be taken is discountable, as the activity will occur in very shallow water surface of the pad will be 6 ft 1.8 m MLLW.
As NMFS stated in the in the In-water Construction Effects on Potential Foraging Habitat section, a small amount of seafloor habitat will be disturbed or covered as a result of pile driving, gravel deposition, screeding, and other seabed preparation; however, for the reasons described in that section, NMFS does not expect those activities to meaningfully impact the amount of habitat available to marine mammals, and it will not result in the take of marine mammals. Further, while the project will likely increase turbidity in the immediate project area, this increased turbidity will be very localized and of a short duration, and it is not expected to have a significant impact on marine mammal habitat for the reasons described in the In-water Construction Effects on Potential Foraging Habitat section of the proposed IHA. The filling and screeding activities could also result in the suspension, and potentially consumption, of contaminants by marine mammal prey, and subsequently marine mammals, as suggested by the commenter; however, given the limited duration of filling and screeding activates, we expect suspension and consumption of contaminants by marine
PO 00000

Frm 00007

Fmt 4701

Sfmt 4703

10663

mammals and their prey would be minimal, and would not impact the fitness of any individual marine mammal.
Installation of the barge bridge involves moving two barges into place against the mooring dolphins with tugs, where they will be ballasted and fastened to the causeway abutments and to each other. Moving the barges into place is expected to occur in a relatively slow, predictable manner, and while marine mammals do respond to vessel noise, NMFS does not expect that any behavioral responses to movement of the barges are likely to qualify as take of marine mammals. Ballasting the barges is unlikely to take a marine mammal, given the nature of the activity.
Regarding discussion of the cumulative impacts from screeding, gravel deposition, and vessel traffic, NMFS has described immediately above and in responses to Comments 13 and 14 for vessel noise and vessel strike why these activities are unlikely to result in the take of marine mammals and the discussion is applicable to the unlikelihood of aggregate impacts of these activities as well.
Comment 12: A commenter stated that geophysical surveys with echosounders and sonar have been linked to marine mammal harm and harassment. The proposed project will include geophysical surveys conducted prior to pipeline construction, including singlebeam echosounder, multi-beam echosounder, and side-scan sonar. In 2008, an Independent Scientific Review Panel identified a multi-beam echosounder as the most plausible and likely behavioral trigger for a massive stranding event of hundreds of whales in Madagascar. In 2002, in the Gulf of California a beaked whale stranding event also correlated with a scientific research survey using multi-beam sonar.
While these echosounders and sonar may have used lower frequencies than the one proposed here, it is concerning that high-power echosounders have the potential to negatively impact marine mammals across far distances from the source. NMFS failed to adequately consider the potential impacts from these surveys, and it should mitigate them with restrictions on low-frequency systems, larger safety zones, and time area closures.
Response: As stated in response to Comment 11, AGDC will perform multibeam echosounder hydrographic surveys to identify high and low spots in the seabed prior to each season;
however, the survey would be conducted with equipment emitting
E:FRFM22FEN2.SGM

22FEN2