Section 1 Introduction - National Marine Fisheries Service - NOAA

NBK at Bangor EHW-1 Pile Replacement Project Final Marine Mammal Monitoring Report
delays to imminent construction from 5 October to 27 October because of harbor seals present in
the shutdown zone (Table 12).
Harbor Porpoise Sightings. A total of 14 harbor porpoise sightings occurred from 4 October to
27 October with a total of 31 individuals (Table 13, Figure 9). Of those 14 sightings, two
sightings (four individuals) were considered to be re-sightings, making a total of 27 individuals
sighted. Six sightings occurred during EHW-1 construction activities, totaling 12 animals. On
7 October, two individuals were seen first at 16:48 (before construction began), again at 16:59
(during a soft start) and again at 17:01 (during actual construction). This sighting represented
two Level B takes, one for each animal, caused by soft start procedures. The animals were not
considered to be “taken” a second time during actual vibratory procedures. Observers were
confident these events were resightings of the same animals, since they were a distinctive
adult/calf pair (see notes in Appendix E). In total, five harbor porpoises were sighted within the
120 dB harassment zone, measured on a per-pile basis (see Appendix F), resulting in five Level
B takes for this species (Table 10).
Steller sea lion sightings. As Steller sea lions typically do not arrive in the vicinity of NBK at
Bangor until well into November (A. Balla-Holden, U.S. Navy, pers. comm.), their appearance
during this project was unexpected. No takes for this species of any kind were permitted under
the issued IHA (NMFS 2011) or through the ESA consultation. The first sighting of this species
during the EHW-1 PRP occurred on 10 October 2011 (Table 14). The majority of sightings
were made near Delta Pier, a berthing facility that accommodates multiple submarines at one
time. The submarines themselves were used as a haul-out site by both Steller and California sea
lions. It is speculated that the heat signature of these vessels provides an attractive haulout site
for pinnipeds to rest and thermoregulate. Based on size and morphology, all Steller sea lions
appeared to be adult or subadult males, and often had mildly agonistic interactions with the
California sea lions also hauled out on the submarines. Steller sea lions were most commonly
observed resting, swimming, and vocalizing, usually during interactions with California sea
lions. One Steller sea lion observed at Delta Pier was branded with a large “102 Y” along its left
flank. This male was branded in July 2002 as a pup at St. George Reef near Crescent City,
California (DeLong and Loughlin 2003).
There were 15 sightings of Steller sea lions for a total of 18 individuals during the course of
EHW-1 repairs. Three of these animals were observed during pile driving. Two of the animals
were hauled out on a submarine at Delta Pier, but the third was seen hauling out onto a
submarine from the water during the course of vibratory driving. As a result, this animal was
noted as a Level B take (Table 14, Figure 5). See Appendix G (photos G-4 and G-5) for a
representative sample of the animals seen and their location relative to the project area.
Sightings that occurred during pile driving activities are indicated in bold type in Table 14.
Resightings of the same animals during pile driving were not considered to be additional takes.
Although several Steller sea lions were observed hauled out during pile driving activities, only
one animal was seen in the water while construction was ongoing. Airborne sound pressure
levels at Delta Pier were never estimated to reach 100 dB; therefore there were no airborne takes
of Steller sea lions (Appendix F, Table 10). Two Steller sea lions were observed swimming in
the WRA (see Figure 5), but both of these sightings were during non-construction periods.
Bangor, Washington 44