NMFS Biological Opinion on U.S. Navy training ... - Govsupport.us

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FINAL PROGRAMMATIC BIOLOGICAL OPINION ON U.S. NAVY ACTIVITIES IN THE HAWAII RANGE COMPLEX 2008-2013 (for example, engine noise, helicopter rotors, ordnance discharges, explosions, or some combination of these) or whether fin whales would avoid being exposed to specific received levels, the entire sound field associated with an exercise, or the general area in which an exercise would occur. Particular whales’ might not respond to the vessels, while in other circumstances, fin whales are likely to change their vocalizations, surface time, swimming speed, swimming angle or direction, respiration rates, dive times, feeding behavior, and social interactions (Amaral and Carlson 2005; Au and Green 2000, Cockeron 1995, Erbe 2002, Félix 2001, Magalhães et al. 2002, Richter et al. 2003, Scheidat et al. 2004, Simmonds 2005, Watkins 1986, Williams et al. 2002). Some of these whales might experience physiological stress (but not “distress”) responses if they attempt to avoid one ship and encounter a second ship during that attempt. However, because of the relatively short duration of the different exercises and the small number of times the exercises are likely to be repeated from December 2008 to December 2013, we do not expect these responses of fin whales to reduce the fitness of the fin whales that occur in the Hawai'i Range Complex. Based on the evidence available, we conclude that training exercises and other activities the U.S. Navy plans to conduct in the Hawai'i Range Complex each year from December 2008 through December 2013 are not likely to adversely affect the population dynamics, behavioral ecology, and social dynamics of individual fin whales in ways or to a degree that would reduce their fitness. As we discussed in the Approach to the Assessment section of this opinion, an action that is not likely to reduce the fitness of individual whales would not be likely to reduce the viability of the populations those individual whales represent (that is, we would not expect reductions in the reproduction, numbers, or distribution of those populations). As a result, the activities the U.S. Navy plans to conduct in the Hawai'i Range Complex each year from December 2008 through December 2013 are not likely to appreciably reduce the fin whales’ likelihood of surviving and recovering in the wild. HUMPBACK WHALES. Because future Rim of the Pacific exercises occurs in the Hawai’i Range Complex in July when humpback whales do not occur in waters off Hawai’i, humpback whales would not be exposed to the potential stressors associated with that exercise so the remainder of this discussions focuses on the probable responses of humpback whales to activities the U.S. Navy plan to conduct in the Hawai'i Range Complex each year from December 2008 through December 2013. As discussed in our Exposure Analyses, we believe the estimates produced by our second and third exposure scenarios are more likely to represent the number of instances in which humpback whale might be exposed to midfrequency active sonar. The second scenario is more representative because it assumes that humpback whales are most likely to avoid initial or continued exposure to active sonar. The third scenario is representative because it captures patterns of abundance and migration by these whales in waters off the Hawai'ian Islands better than the alternatives. However, both models are sensitive to our assumptions about the rate at which whale densities would change in response to initial or continued exposure and when training activities would actually occur (that is, the scenarios are sensitive to assumptions about whether they would be evenly distributed throughout the year, would occur primarily during periods of low humpback whale density, or during periods of high humpback whale density). Based on the information that is available, we would not expect humpback whales to be exposed to sound fields produced by active sonar associated with all of the training exercises and other activities that would occur in the 242
FINAL PROGRAMMATIC BIOLOGICAL OPINION ON U.S. NAVY ACTIVITIES IN THE HAWAII RANGE COMPLEX 2008-2013 Hawai'i Range Complex over the next five years. For example, monitoring surveys associated with the November 2007 Undersea Warfare Exercises did not report any sightings of humpback whales while monitoring surveys associated with the March 2008 Undersea Warfare Exercises reported 40 sightings of 68 humpback whales during the exercise. Nevertheless, for the purposes of our analyses and assuming that humpback whales would be exposed to active sonar associated with all training exercises that occur during their tenure in Hawai'i, we would expect each USWEX exercise would result in between 1,682 and 5,448 instances in which humpback whales might be exposed to active sonar (between 8,410 and 27, 240 instances of exposure each year) while the other 32 anti-submarine warfare exercises would result in between 991 and 6,425 instances in which humpback whales might be exposed to active sonar. We assume that the humpback whales that might be exposed to active sonar between their arrival in waters off Hawai'i might be any gender, age, or reproductive condition. However, historic patterns suggest that immature humpback whales and females without calves would arrive in the Maui Basin and Penguin Banks before females with calves, pregnant females, and males; as discussed previously, the pattern off the Island of Hawai'i is different (females without calves arrive before immature whales) and may be different in other areas of Hawai'i. Because humpback whales do not tend to reside in waters off Hawai'i for more than 6 to 8 weeks, we would not expect individual whales to be exposed to major training exercises (for example, Undersea Warfare Exercises) multiple times, although individual whales might be exposed to multiple unit-level or intermediate-level training exercises. Humpback whales produce a wide variety of sounds. During the breeding season males sing long, complex songs, with frequencies in the 25-5000 Hz range and intensities as high as 181 dB (Payne 1970; Winn et al. 1970a; Thompson et al. 1986). Source levels average 155 dB and range from 144 to 174 dB (Thompson et al. 1979). The songs appear to have an effective range of approximately 10 to 20 km. Animals in mating groups produce a variety of sounds (Tyack 1981; Tyack and Whitehead 1983, Silber 1986). Humpback whales produce sounds less frequently in their summer feeding areas. Feeding groups produce distinctive sounds ranging from 20 Hz to 2 kHz, with median durations of 0.2-0.8 sec and source levels of 175-192 dB (Thompson et al. 1986). These sounds are attractive and appear to rally animals to the feeding activity (D’Vincent et al. 1985; Sharpe and Dill 1997). Humpback whales have been known to react to low frequency industrial noises at estimated received levels of 115- 124 dB (Malme et al. 1985), and to conspecific calls at received levels as low as 102 dB (Frankel et al. 1995). Malme et al. (1985) found no clear response to playbacks of drill ship and oil production platform noises at received levels up to 116 dB re 1 μPa. Studies of reactions to airgun noises were inconclusive (Malme et al. 1985). Humpback whales on the breeding grounds did not stop singing in response to underwater explosions (Payne and McVay 1971). Humpback whales on feeding grounds did not alter short-term behavior or distribution in response to explosions with received levels of about 150dB re 1 μPa/Hz at 350Hz (Lien et al. 1993; Todd et al. 1996). However, at least two individuals were probably killed by the high-intensity, impulsed blasts and had extensive mechanical injuries in their ears (Ketten et al. 1993; Todd et al. 1996). The explosions may also have increased the number of humpback whales entangled in fishing nets (Todd et al. 1996). Frankel and Clark (1998) showed that breeding humpbacks showed only a slight statistical reaction to playbacks of 60 - 90 Hz sounds with a received level of up to 243
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