Voglio sapere a riguardo di…

khammond on DSKJM1Z7X2PROD with RULES2

43062

Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Rules and Regulations
did not result in an observed detrimental response i.e., nonresponses in the comment do not necessarily indicate that the animals were unaffected Frid and Dill 2002, Bejder et al. 2006, Laske et al. 2011;
hence, our classification of likely physiological response. Arousals during denning can lead to some increases in body temperature Craighead et al. 1976, Laske et al. 2011, Evans et al. 2016b and heart rate Reynolds et al. 1986, Evans et al.
2016b, both of which require use of valuable energy reserves. Across taxa, unobserved effects, including higher levels of stress hormones Moberg 2000, Keay et al. 2006 and others have been shown to have the potential to be equally as consequential for reproduction Carney and Sydeman 1999, Ellenberg et al. 2006, Rode et al.
2018b. Decreased reproductive success or reproductive failure in bears is documented as a consequence of denning disturbance Ramsay and Dunbrack 1986, Amstrup and Gardner 1994, Linnell et al. 2000, Swenson et al.
1997.
Comment 130: One commenter suggested that the Service should consider additional factors that may cause a polar bear to emerge early from her den without necessarily resulting in reduced cub production and survival, which are referenced in the Rode et al.
2018 study.
Response: We agree with the commenter that there are other hypotheses that may explain the results of Rode et al. 2018, as we acknowledge in the proposed ITR p. 29393.
However, Rode et al. 2018 does indicate that the most likely explanation for their results is the earlier emergence leading to survival consequences for cubs. This makes sense given the altricial nature of cubs when born and the time bears spend at the den site after emergence to allow cubs time to grow more and become acclimated to the outside environment. We do attempt to take into account some of the other causes of emerging from a den without cubs. We allow an average of 7% of simulated dens to emerge without any cubs, so we do account for some females naturally emerging without any offspring, which are not attributed to any form of disturbance from industrial activity. We disagree, however, that because there are other potential hypotheses for the relationship presented in Rode et al. 2018 that we have to ignore the relationship she published. As it currently stands, we dont have any additional data to suggest that the relationship documented in Rode et al. 2018 isnt
VerDate Sep<11>2014

17:26 Aug 04, 2021

Jkt 253001

accurate as portrayed. However, if additional information is published in the future, that would be considered the best scientific information available and we would use it accordingly.
Comment 131: One commenter suggested that the Service should consider whether the variability of mobile activities will affect occupancy rates used to determine take estimates and whether take estimates are overestimated from a conservative occupancy rate.
Response: Occupancy rates for all of the different infrastructure was provided by AOGA as part of their Request.
Comment 132: One commenter suggested that the Service should estimate take for Level A and Level B
harassment zones for in-water activities.
Response: The Service has revised Table 1 to include details regarding the sound measurement units and included peak SPL for impulsive sound sources.
The Service has also revised references to past ITR Level B harassment and TTS
thresholds. With regards to the need for Level A harassment zones, the Service did not calculate this area as no sound sources identified in the proposed activities would produce Level A
threshold noise. As was stated in the proposed rule, the Level B harassment zone was smaller than the impact area of surface activities, so we estimated take using the more conservative impact area.
Comment 133: One commenter suggested that the Service should consider whether the number of takes during aircraft overflights is underestimated considering the increased use of helicopters compared to previous years and the higher polar bear response rate to helicopters.
Response: Any flight paths associated with major construction activities have been incorporated into the aircraft analysis. AOGA provided the Service with a list of aircraft that would likely be used for each activityan increase in helicopter use is speculative. While the harassment rates were calculated using data from AeroCommander flights, the Service discusses results from observational flights using helicopters.
The harassment rates associated with these helicopter flights were found to be lower than the rates used in the AOGA
Request. No significant relationship between polar bear response and distance to aircraft was concluded from the dataset. We are working to further refine our take rates associated with these analyses; however, more data is needed before we can differentiate take rates based on the type of aircraft. More detailed information on behavioral
PO 00000

Frm 00082

Fmt 4701

Sfmt 4700

responses from these overflights can be found in the ITR section Aircraft Impacts to Surface Bears.
Comment 134: A recent peer-reviewed article, Polar bear behavioral response to vessel surveys in northeastern Chukchi Sea, 20082014 by LomacMacNair et al. 2021, should be incorporated into the Services analysis of behavioral responses of polar bears to vessel activity as information in the publication could be used to improve the in-water analysis and could also supplement and support established mitigation measures, such as set-back distances for polar bears, as well.
Response: We agree Lomac-MacNair et al. 2021 is a valuable addition to the body of polar bear disturbance literature. However, the paper published after the proposed rule was published for public comment. We have reviewed the publication, and the authors findings are consistent with the current impact areas used in the proposed and final rules.
Comment 135: The Services discussion of the peer-reviewed article Aquatic behaviour of polar bears Ursus maritimus in an increasingly ice-free Arctic. Lone, et al. 2018, appears to misstate or overstate conclusions contained in that article.
Response: The Service has clarified our discussion regarding the conclusions we draw from this article as needed.
Comment 136: The Service should supplant the Southall et al. 2019
modeled and extrapolated approach by gathering hearing data i.e., TTS and PTS specific to polar bears, rather than relying solely on information attributed to other marine carnivores, and use polar bear-specific acoustic information for future analyses.
Response: We agree that our analysis could be improved with species-specific information for polar bear responses to sound. We also recognize that such efforts may be challenging to obtain on polar bears in the wild or held in captivity. However, we will continue to improve our understanding of polar bear hearing acuity as feasible.
Comment 137: The Service should supplant the Southall et al. 2019
modeled and extrapolated approach by gathering hearing data i.e., TTS and PTS specific to walruses, rather than relying solely on information attributed to other marine carnivores, and use walrus-specific acoustic information for future analyses.
Response: As noted above, we agree that our analysis could be improved with species-specific information for Pacific walrus responses to sound. We also recognize that such efforts may be
E:FRFM05AUR2.SGM

05AUR2