PROJECTS

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from September 2017 to June 2018 and from April to September 2019 to record the low-frequency ambient soundscape and detect marine mammal and anthropogenic sounds during times of naval exercises in the area. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at two locations: a continental slope site in deep water (~900–1,000 m depth, site CB) and a deep-water site off Kodiak Island (~1,000 m depth, site KOA). The low-frequency ambient soundscape showed spectrum level peaks at both sites during winter and fall, related to the seasonally increased presence of blue and fin whales.

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from September 2017 to September 2019 to record the low-frequency ambient soundscape and detect marine mammal and anthropogenic sounds during times of naval exercises in the area. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at two locations: a continental slope site in deep water (~900–1,000 m depth, site CB) and a continental shelf site off Kodiak Island (~1,000 m depth, site KOA).

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from May to September 2015 and from April to September 2017 to record the low-frequency ambient soundscape and detect marine mammal and anthropogenic sounds during times of naval exercises in the area. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at three locations: a continental slope site in deep water (900 m depth, site CB), a deep water site (hydrophone was placed at 1200 m at a location where depth was approximately 4000 m, site AB), and a deep offshore site at Quinn Seamount (900 m depth, site QN).

A pair of fin whales (Balaenoptera physalus) were concurrently tracked in the Gulf of Alaska from their 40-Hz calls recorded on an array of passive acoustic monitoring instruments. Calls were produced during movement of the whales along convergent tracks, but following a close-approach (~500 m) between the whales, there was no extended period of close proximity. Call frequency, swim speed, and root-mean-square (rms) source sound pressure levels (SL) were different between the two animals. One whale called more frequently, more often, at a higher frequency and with higher SL, but had slower swim speeds than the other whale.

Underwater ambient and anthropogenic sounds were recorded over multiple years at two U.S. Navy training areas, one in the Gulf of Alaska and the other offshore of the northwest coast of the continental U.S. The Gulf of Alaska Temporary Maritime Activities Area (GATMAA) was acoustically monitored for marine mammal, ambient, and anthropogenic sounds from July 2011 to September 2015. The Northwest Training Range Complex (NWTRC) was also monitored for sounds from marine mammals, ambient soundscape, and anthropogenic sources from September 2004 to May 2014.

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from April 2014 to May 2015 to detect marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at five locations: a shelf site offshore Kenai Peninsula (200 m depth, site CA), a continental slope site in deep water (900 m depth, site CB), a slope site offshore Kodiak Island (200 m depth, site KO), a deep offshore site at Pratt Seamount (1000 m depth, site PT), and a deep offshore site at Quinn Seamount (900 m depth, site QN).

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from June 2013 to May 2014 to detect marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at five locations: a shelf site offshore Kenai Peninsula (200 m depth, site CA), a continental slope site in deep water (850 m depth, site CB), a slope site offshore Kodiak Island (230 m depth, site KO), a deep offshore site at Pratt Seamount (1000 m depth, site PT), and a deep offshore site at Quinn Seamount (930 m depth, site QN).