Je veux savoir à propos de…

Federal Register / Vol. 86, No. 171 / Wednesday, September 8, 2021 / Proposed Rules The gradual and deliberate approach to the islet resulted in the sea lions present initially becoming aware of the helicopter and calmly moving into the water. Further, the USFWS reported that all responses fell well within the range of Level B harassment i.e., limited, short-term displacement resulting from aircraft noise due to helicopter overflights.
Several factors complicate the analysis of longand short-term effects for aircraft overflights. Information on behavioral effects of overflights by military aircraft or component stressors on most wildlife species is sparse. Moreover, models that relate behavioral changes to abundance or reproduction, and those that relate behavioral or hearing effects thresholds from one population to another are generally not available. In addition, the aggregation of sound frequencies, durations, and the view of the aircraft into a single exposure metric is not always the best predictor of effects and it may also be difficult to calculate.
Overall, there has been no indication that single or occasional aircraft flying above pinnipeds in water cause long term displacement of these animals Richardson et al., 1995. The Lowest Observed Adverse Effects Level LOAEL for aircraft elevation disturbance are rather variable for pinnipeds on land, ranging from just over 150 m 492 ft to about 2,000 m 6,562 ft Efroymson et al., 2001.
Bowles and Stewart 1980 estimated an LOAEL of 305 m 1,000 ft for helicopters low and landing affecting California sea lions and harbor seals observed on San Miguel Island, CA;

animals responded to some degree by moving within the haulout and entering into the water, stampeding into the water, or clearing the haul out completely. Both species always responded with the raising of their heads. California sea lions appeared to react more to the visual cue of the helicopter than the noise.
It is possible that the initial helicopter approach to NWSR would cause a subset of the marine mammals hauled out to react. CCR found a range of from 0 to 40 percent of all pinnipeds present on the island were temporarily displaced flushed due to initial helicopter landings in 1998. Their data suggested that the majority of these animals returned to the island once helicopter activities ceased, over a period of minutes to 2 hours CCR, 2001. Far fewer animals flushed into the water on subsequent takeoffs and landings, suggesting rapid habituation to helicopter landing and departure CCR, 2001; Guy Towers, Society, pers.
comm.. CCRs data also showed that the number of pinnipeds that flush is low when takeoffs and landings occur less than 30 minutes apart, which is the case for all of the flights by the Society.
Observations from monitoring to date for this work confirms the above pattern of partial flushing at initial landing and increasing habituation thereafter.
Any noise associated with restoration and maintenance activities is likely to be from light construction e.g., sanding, hammering, or use of hand drills. The Society will confine all restoration activities to inside the existing structure, which would occur mostly on the upper levels of the Station.

50311

Pinnipeds hauled out on NWSR do not have access to the upper levels of the Station and sound levels are not likely to exceed the thresholds.
Human Presence The appearance of Society personnel may have the potential to cause Level B
harassment of marine mammals hauled out on NWSR. Disturbance includes a variety of effects, from subtle to conspicuous changes in behavior, movement, and displacement.
Disturbance may result in reactions ranging from an animal simply becoming alert to the presence of the Societys restoration personnel e.g., turning the head, assuming a more upright posture to flushing from the haulout site into the water. NMFS does not consider the lesser reactions to constitute behavioral harassment, or Level B harassment takes, but rather assumes that pinnipeds that move greater than two body lengths or longer, or if already moving, a change of direction of greater than 90 degrees in response to the disturbance, or pinnipeds that flush into the water, are behaviorally harassed, and thus considered incidentally taken by Level B harassment. NMFS uses a 3-point scale Table 2 to determine which disturbance reactions constitute take under the MMPA. Levels two and three movement and flush are considered take, whereas level one alert is not.
Animals that respond to the presence of the Societys personnel by becoming alert, but do not move or change the nature of locomotion as described, are not considered to have been subject to behavioral harassment.

TABLE 2DISTURBANCE SCALE OF PINNIPED RESPONSES TO IN-AIR SOURCES TO DETERMINE TAKE
Level
Type of response
Definition
1

Alert

2

Movement

3

Flush

Seal head orientation or brief movement in response to disturbance, which may include turning head towards the disturbance, craning head and neck while holding the body rigid in a u-shaped position, changing from a lying to a sitting position, or brief movement of less than twice the animals body length.
Movements in response to the source of disturbance, ranging from short withdrawals at least twice the animals body length to longer retreats over the beach, or if already moving a change of direction of greater than 90 degrees.
All retreats flushes to the water.

jbell on DSKJLSW7X2PROD with PROPOSALS

Only Levels 2 and 3 are considered take, whereas Level 1 is not.

Reactions to human presence, if any, depend on species, state of maturity, experience, current activity, reproductive state, time of day, and many other factors Richardson et al., 1995; Southall et al., 2007; Weilgart 2007. If a marine mammal does react briefly to human presence by changing its behavior or moving a small distance, the impacts of the change are unlikely
VerDate Sep<11>2014

16:57 Sep 07, 2021

Jkt 253001

to be significant to the individual, let alone the stock or population. However, if visual stimuli from human presence displace 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. Nevertheless, this is not likely to occur during the
PO 00000

Frm 00023

Fmt 4702

Sfmt 4702

proposed activities since rapid habituation or movement to nearby haulouts is expected to occur after a potential pinniped flush.
Disturbances resulting from human activity can impact shortand long-term pinniped haulout behavior Renouf et al., 1981; Schneider and Payne, 1983;
Terhune and Almon, 1983; Allen et al., 1984; Stewart, 1984; Suryan and
E:FRFM08SEP1.SGM

08SEP1