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Federal Register / Vol. 86, No. 171 / Wednesday, September 8, 2021 / Proposed Rules
Harvey, 1999; and Kucey and Trites, 2006. Numerous studies have shown that human activity can flush harbor seals off haulout sites Allen et al., 1984;
Calambokidis et al., 1991; and Suryan and Harvey 1999 or lead Hawaiian monk seals Neomonachus schauinslandi to avoid beaches Kenyon 1972. In one case, human disturbance appeared to cause Steller sea lions to desert a breeding area at Northeast Point on St. Paul Island, Alaska Kenyon 1962.
In cases where vessels actively approached marine mammals e.g., whale watching or dolphin watching boats, scientists have documented that animals exhibit altered behavior such as increased swimming speed, erratic movement, and active avoidance behavior Acevedo, 1991; Trites and Bain, 2000; Williams et al., 2002;
Constantine et al., 2003, reduced blow interval Richter et al., 2003, disruption of normal social behaviors Lusseau 2003; 2006, and the shift of behavioral activities which may increase energetic costs Constantine et al., 2003; 2004. In 1997, Henry and Hammil 2001
conducted a study to measure the impacts of small boats i.e., kayaks, canoes, motorboats and sailboats on harbor seal haul out behavior in Metis Bay, Quebec, Canada. During that study, the authors noted that the most frequent disturbances n=73 were caused by lower speed, lingering kayaks, and canoes 33.3 percent as opposed to motorboats 27.8 percent conducting high speed passes. The seals flight reactions could be linked to a surprise factor by kayaks and canoes which approach slowly, quietly, and low on the water making them look like predators. However, the authors note that once the animals were disturbed, there did not appear to be any significant lingering effect on the recovery of numbers to their predisturbance levels. In conclusion, the study showed that boat traffic at current levels has only a temporary effect on the haul out behavior of harbor seals.
In 2004, Acevedo-Gutierrez and Johnson 2007 evaluated the efficacy of buffer zones for watercraft around harbor seal haulout sites on Yellow Island, Washington. The authors estimated the minimum distance between the vessels and the haulout sites; categorized the vessel types; and evaluated seal responses to the disturbances. During the course of the 7weekend study, the authors recorded 14
human-related disturbances which were associated with stopped powerboats and kayaks. During these events, hauled out seals became noticeably active and moved into the water. The flushing
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occurred when stopped kayaks and powerboats were at distances as far as 453 and 1,217 ft 138 and 371 m, respectively. The authors note that the seals were unaffected by passing powerboats, even those approaching as close as 128 ft 39 m, possibly indicating that the animals had become tolerant of the brief presence of the vessels and ignored them. The authors reported that on average, the seals quickly recovered from the disturbances and returned to the haulout site in less than or equal to 60 minutes. Seal numbers did not return to predisturbance levels within 180 minutes of the disturbance less than one quarter of the time observed. The study concluded that the return of seal numbers to pre-disturbance levels and the relatively regular seasonal cycle in abundance throughout the area counter the idea that disturbances from powerboats may result in site abandonment Johnson and AcevedoGutierrez, 2007.
Stampede There are other ways in which disturbance, as described previously, could result in more than Level B
harassment of marine mammals. They are most likely to be consequences of stampeding, a potentially dangerous occurrence in which large numbers of animals succumb to mass panic and rush away from a stimulus. These situations are particularly injurious when: 1 Animals fall when entering the water at high-relief locations; 2
there is extended separation of mothers and pups; and 3 crushing of pups by large males occurs during a stampede.
However, NMFS does not expect any of these scenarios to occur at NWSR as the proposed action occurs outside of the pupping/breeding season, no mother/
pup pairs are expected to be at the Station, there are no cliffs on NWSR, and previous monitoring has not recorded stampeding events during prior authorizations. The haulout sites at NWSR consist of ridges with unimpeded and non-obstructive access to the water. If disturbed, the small number of hauled out adult animals may move toward the water without risk of encountering barriers or hazards that would otherwise prevent them from leaving the area or increase injury potential. Moreover, the proposed area would not be crowded with large numbers of Steller sea lions, further eliminating the possibility of potentially injurious mass movements of animals attempting to vacate the haulout. Thus, in this case, NMFS considers the risk of injury, serious injury, or death to hauled out animals as extremely low.

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Stress Responses An animals perception of a threat may be sufficient to trigger stress responses consisting of some combination of behavioral responses, autonomic nervous system responses, neuroendocrine responses, or immune responses e.g., Seyle, 1950; Moberg, 2000. In many cases, an animals first and sometimes most economical in terms of energetic costs response is behavioral avoidance of the potential stressor. Autonomic nervous system responses to stress typically involve changes in heart rate, blood pressure, and gastrointestinal activity. These responses have a relatively short duration and may or may not have a significant long-term effect on an animals fitness.
Neuroendocrine stress responses often involve the hypothalamus-pituitaryadrenal system. Virtually all neuroendocrine functions that are affected by stressincluding immune competence, reproduction, metabolism, and behaviorare regulated by pituitary hormones. Stress-induced changes in the secretion of pituitary hormones have been implicated in failed reproduction, altered metabolism, reduced immune competence, and behavioral disturbance e.g., Moberg, 1987; Blecha, 2000.
Increases in the circulation of glucocorticoids are also equated with stress Romano et al., 2004.
The primary distinction between stress which is adaptive and does not normally place an animal at risk and distress is the 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 serious fitness consequences. 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 functions. This state of distress will last until the animal replenishes its energetic reserves sufficient to restore normal function.
Relationships between these physiological mechanisms, animal behavior, and the costs of stress responses are well-studied through controlled experiments and for both laboratory and free-ranging animals e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; Lankford et al., 2005. Stress responses due to exposure to anthropogenic sounds or other stressors and their effects on marine mammals have also been reviewed Fair and Becker, 2000; Romano et al., 2002b
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