Section 1 Introduction - National Marine Fisheries Service - NOAA

NBK at Bangor EHW-1 Pile Replacement Project Final Marine Mammal Monitoring Report
3. No marine mammals were observed within the 164 ft (50 m) EZ during the 3 pulses of
hammer activity associated with soft start of the vibratory hammer.
4. Any marine mammal that entered the 164 ft (50 m) EZ did so of its own volition, and was
therefore, not being injured or frightened by the sound energy being produced by the
hammer.
5. Pile driving was allowed to continue while the MMOs tracked the animal to note its
distance from the pile, and to observe any signs of behavioral distress.
6. If signs of behavioral distress were noted, an all-stop on construction was implemented
(Note: this situation never occurred during EHW-1 construction activities).
All five instances where the “hazardous piling” standard was invoked occurred on 15 and 17
October, and all resulted in Level B harbor seal takes (Tables 10 and 12). There were no Level
A takes for any marine mammal species during the EHW-1 PRP because the average RMS
sound level recorded during construction activity was 166 dB RMS (re: 1µPa) at 10 meters
which would be below the injury thresholds for both pinnipeds and cetaceans at the source.
Even the maximum RMS sound level recorded of 174 dB RMS (re: 1µPa) at 10 meters would be
below the pinnipeds injury threshold of 190 dB RMS at the source and would only be above the
cetacean injury threshold of 180 dB RMS out to less than 4 meters from the pile (NAVFAC
2012). No cetacean ever approached or entered the WRA (over 500 meters from EHW-1)
therefore there was no risk of injury to these species even though the sound pressure levels were
above the 180 dB isopleth on occasion.
During non-hazardous pile driving, there were five construction shutdowns and 20 construction
delays due to: (1) marine mammals (in all cases harbor seals) present in the 164 ft (50 m)
shutdown zone prior to, or during, pile driving activities; or (2) Steller sea lions observed in the
water or moving towards the water while hauled out on submarines at Delta Pier (Figure 5).
Either of these scenarios triggered an automatic shutdown of construction to avoid unauthorized
Level B Steller sea lion takes (Table 10). After 12 October, two MMOs were stationed the Delta
Pier during construction in order to perform regular Steller sea lion counts and behavioral focal
follows. If a Steller sea lion was observed changing from a resting to active behavioral state
while hauled out at Delta pier, the Delta Pier MMO alerted the MC of the potential for a
shutdown via handheld VHF radio. If the animal(s) moved towards the water, the MC
immediately initiated a construction shutdown, or delayed imminent construction (Table 12).
Construction was delayed on 14 October because of a Steller sea lion moving towards the water
from a resting position. Construction was not resumed until the MMO and MC were confident
that the animal did not intend on returning to the water. Construction was delayed again on
15 October because of a Steller sea lion observed in the water prior to construction start, and
construction was not allowed to resume until the animal had left the monitored zone. Ongoing
construction was shut down on 21 October because a Steller sea lion was observed coming out of
the water to haul out on a submarine. The animal approached the submarine from a distance
while remaining underwater, and was therefore unseen by the MMOs until it hauled out, as a
result this observation was recorded as an unauthorized Level B take.
Another four construction shutdowns were triggered on 12 October, 13 October and 27 October
due to a harbor seal observed within the shutdown zone while construction was ongoing. In all
cases, construction was not resumed until the animal had left the area. There were a total of 20
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