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

FINAL PROGRAMMATIC BIOLOGICAL OPINION ON U.S. NAVY ACTIVITIES IN THE HAWAII RANGE COMPLEX 2008-2013
proposes to conduct in the Hawai'i Range Complex transmits at frequencies that are substantially higher than the
hearing thresholds of sea turtles. As a result, sea turtles are not likely to respond upon being exposed to midfrequency
active sonar.
5.3.5 Probable Responses of Listed Species to Explosions
The U.S. Navy proposes to employ a suite of measures to protect endangered and threatened marine mammals and
sea turtles from being exposed to underwater detonations and mining operations during the activities they plan to
conduct in the Hawai'i Range Complex (including sinking exercises). These measures involve site-selection
procedures, exclusion zones, and monitoring protocols that comply with Marine Protection, Research, and
Sanctuaries Act permits as well as procedures developed and tested during the ship shock trial on the USS WINSTON S
CHURCHILL. These monitoring protocols were studied extensively (Clarke and Norman 2005) and those studies
concluded that the monitoring protocols effectively insured that marine mammals or sea turtles did not occur within
3.7 kilometers of the underwater detonations.
Despite these protective measures, the U.S. Navy identified five instances in which humpback whales might be
exposed to pressure waves or sound fields associated with underwater detonations at received levels that would
cause behaviors that would be considered behavioral harassment (as that term is defined by the MMPA) and in
another four instances in which humpback whales might be exposed at received levels that might temporarily cause
noise-induced hearing losses. that five humpback whales might be exposed to pressure waves or sound fields
associated with underwater detonations and another four humpback whales might be exposed at received levels that
might temporarily cause noise-induced hearing losses. In addition, in nine instances in which sperm whales might be
exposed to pressure waves or sound fields associated with underwater detonations at received levels that would
cause behaviors that would be considered behavioral harassment (as that term is defined by the MMPA) and in
another four instances in which sperm whales might be exposed at received levels that might temporarily cause
noise-induced hearing losses. that five humpback whales might be exposed to pressure waves or sound fields
associated with underwater detonations and another four humpback whales might be exposed at received levels that
might temporarily cause noise-induced hearing losses. In three instances, Hawai’ian monk seals might be exposed at
received levels sufficient to temporarily cause noise-induced hearing loss. The Navy’s analyses and our analyses did
not estimate the number of instances in which one or more species of sea turtle might be exposed to pressure waves
or sound field associated with underwater detonations.
Humpback whales were not reported to change the short-term behavior or distribution in feeding areas 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 as they avoided the area in which the detonations occurred (Todd et al.
1996).
Klima et. al. (1988) conducted an experiment in which Kemp’s ridley and loggerhead turtles were placed in cages at
four distances from a oil platform to be removed with explosives. The cages were submerged to a depth of 15 ft over
the 30 ft sea bottom just prior to the simultaneous explosion of four 50.75 lb charges of nitromethane placed inside
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