Journal of the Acoustical Society of America, Oct 1, 2014
A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of... more A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of Alaska (GoA) during the summer of 2013. The survey area was divided into four sub-strata to reflect four distinct habitats; “inshore,” “slope,” “offshore,” and “seamount.” Passive acoustic monitoring was conducted using a towed-hydrophone array system. One of the main objectives of the acoustic survey was to obtain an acoustic-based density estimate for sperm whales. A total of 241 acoustic encounters of sperm whales during 6,304 km of effort were obtained compared to 19 visual encounters during 4,155 km of effort. Line-transect analytical methods were used to estimate the abundance of sperm whales. To estimate the detection function, target motion analysis was used to obtain perpendicular distances to individual sperm whales. An acoustic-based density and abundance estimate was obtained for each stratum (N = 78; CV = 0.36 offshore; N = 16; CV = 0.55 seamount; N = 121; and CV = 0.18 slope) and for the entire survey area (N = 215; D = 0.0013; and CV = 0.18). These results will be compared to visual-based estimates. The advantages and disadvantages of acoustic-based density estimates as well as application of these methods to other species (e.g., beaked whales) and areas will be discussed.
NOTE – March 2008: In areas outside of Alaska, studies have shown that stock structure is more fi... more NOTE – March 2008: In areas outside of Alaska, studies have shown that stock structure is more fine-scale than is reflected in the Alaska Stock Assessment Reports. At this time, no data are available to reflect stock structure for harbor porpoise in Alaska. However, based on comparisons with other regions, smaller stocks are likely. Should new information on harbor porpoise stocks become available, the harbor porpoise Stock Assessment Reports will be updated.
Risso’s dolphins (Grampus griseus), uncommon prior to the 1970’s, are now regularly observed with... more Risso’s dolphins (Grampus griseus), uncommon prior to the 1970’s, are now regularly observed within the Southern California Bight. During long-term cetacean monitoring programs on United States Navy range areas in the Southern California Bight from 2009–2019, we deployed 16 Argos-linked satellite tags on Risso’s to acquire objective, detailed depictions of their movements and behaviors. Individuals were tracked for a median of 10.7 days (range = 0.8 – 19.7). Kernel density estimation suggested individuals utilized the entire Southern California Bight with the 50% core use area centered around San Clemente and Santa Catalina Islands where most of the tag deployments occurred. Grand median dive depth was 101 m (max = 528) and dive duration was 5.6 min (max = 11.1). We used generalized mixed models to assess seasonal and environmental effects on distribution and diving behavior including month, distance to shore, time of day, lunar phase, sea surface temperature, and chlorophyll-a resi...
Widespread use of unregulated acoustic technologies in maritime industries raises concerns about ... more Widespread use of unregulated acoustic technologies in maritime industries raises concerns about effects on acoustically sensitive marine fauna worldwide. Anthropogenic noise can disrupt behavior and may cause short- to long-term disturbance with possible population-level consequences, particularly for animals with a limited geographic range. Ultrasonic antifouling devices are commercially available, installed globally on a variety of vessel types, and are marketed as an environmentally-friendly method for biofouling control. Here we show that they can be an acoustic disturbance to marine wildlife, as seasonal operation of these hull-mounted systems by tourist vessels in the marine protected area of Guadalupe Island, México resulted in the reduced presence of a potentially resident population of Cuvier’s beaked whales (Ziphius cavirostris). Human activities are rapidly altering soundscapes on local and global scales, and these findings highlight the need to identify key noise source...
Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collecti... more Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
Journal of the Acoustical Society of America, Oct 1, 2014
A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of... more A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of Alaska (GoA) during the summer of 2013. The survey area was divided into four sub-strata to reflect four distinct habitats; “inshore,” “slope,” “offshore,” and “seamount.” Passive acoustic monitoring was conducted using a towed-hydrophone array system. One of the main objectives of the acoustic survey was to obtain an acoustic-based density estimate for sperm whales. A total of 241 acoustic encounters of sperm whales during 6,304 km of effort were obtained compared to 19 visual encounters during 4,155 km of effort. Line-transect analytical methods were used to estimate the abundance of sperm whales. To estimate the detection function, target motion analysis was used to obtain perpendicular distances to individual sperm whales. An acoustic-based density and abundance estimate was obtained for each stratum (N = 78; CV = 0.36 offshore; N = 16; CV = 0.55 seamount; N = 121; and CV = 0.18 slope) and for the entire survey area (N = 215; D = 0.0013; and CV = 0.18). These results will be compared to visual-based estimates. The advantages and disadvantages of acoustic-based density estimates as well as application of these methods to other species (e.g., beaked whales) and areas will be discussed.
NOTE – March 2008: In areas outside of Alaska, studies have shown that stock structure is more fi... more NOTE – March 2008: In areas outside of Alaska, studies have shown that stock structure is more fine-scale than is reflected in the Alaska Stock Assessment Reports. At this time, no data are available to reflect stock structure for harbor porpoise in Alaska. However, based on comparisons with other regions, smaller stocks are likely. Should new information on harbor porpoise stocks become available, the harbor porpoise Stock Assessment Reports will be updated.
Risso’s dolphins (Grampus griseus), uncommon prior to the 1970’s, are now regularly observed with... more Risso’s dolphins (Grampus griseus), uncommon prior to the 1970’s, are now regularly observed within the Southern California Bight. During long-term cetacean monitoring programs on United States Navy range areas in the Southern California Bight from 2009–2019, we deployed 16 Argos-linked satellite tags on Risso’s to acquire objective, detailed depictions of their movements and behaviors. Individuals were tracked for a median of 10.7 days (range = 0.8 – 19.7). Kernel density estimation suggested individuals utilized the entire Southern California Bight with the 50% core use area centered around San Clemente and Santa Catalina Islands where most of the tag deployments occurred. Grand median dive depth was 101 m (max = 528) and dive duration was 5.6 min (max = 11.1). We used generalized mixed models to assess seasonal and environmental effects on distribution and diving behavior including month, distance to shore, time of day, lunar phase, sea surface temperature, and chlorophyll-a resi...
Widespread use of unregulated acoustic technologies in maritime industries raises concerns about ... more Widespread use of unregulated acoustic technologies in maritime industries raises concerns about effects on acoustically sensitive marine fauna worldwide. Anthropogenic noise can disrupt behavior and may cause short- to long-term disturbance with possible population-level consequences, particularly for animals with a limited geographic range. Ultrasonic antifouling devices are commercially available, installed globally on a variety of vessel types, and are marketed as an environmentally-friendly method for biofouling control. Here we show that they can be an acoustic disturbance to marine wildlife, as seasonal operation of these hull-mounted systems by tourist vessels in the marine protected area of Guadalupe Island, México resulted in the reduced presence of a potentially resident population of Cuvier’s beaked whales (Ziphius cavirostris). Human activities are rapidly altering soundscapes on local and global scales, and these findings highlight the need to identify key noise source...
Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collecti... more Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
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