509 research outputs found
Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring
No full textThis work was funded by two partners under the National Oceanographic Partnership Program: the Ocean Acoustics Program of the U.S. National Marine Fisheries Service, Office of Protected Resources, and the International Association of Oil and Gas Producers Joint Industry Programme on Exploration and Production Sound and Marine Life. Research permits were issued to John Boreman (US NMFS 1121-1900), Peter Tyack (US NMFS 981-1578), and Ian Boyd (Bahamas permit #02/07). M.J. and P.T. are supported by the Marine Alliance for Science and Technology Scotland.The presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dB(rms97). The mean 3 dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13 degrees and 23 dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6 degrees/s over an angular range of some +/-10 degrees. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging. [http://dx.doi.org/10.1121/1.4776177]Peer reviewe
Vessel noise affects beaked whale behavior : results of a dedicated acoustic response study
No full text© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 7 (2012): e42535, doi:10.1371/journal.pone.0042535.Some beaked whale species are susceptible to the detrimental effects of anthropogenic noise. Most studies have
concentrated on the effects of military sonar, but other forms of acoustic disturbance (e.g. shipping noise) may disrupt
behavior. An experiment involving the exposure of target whale groups to intense vessel-generated noise tested how these
exposures influenced the foraging behavior of Blainville’s beaked whales (Mesoplodon densirostris) in the Tongue of the
Ocean (Bahamas). A military array of bottom-mounted hydrophones was used to measure the response based upon
changes in the spatial and temporal pattern of vocalizations. The archived acoustic data were used to compute metrics of
the echolocation-based foraging behavior for 16 targeted groups, 10 groups further away on the range, and 26 nonexposed
groups. The duration of foraging bouts was not significantly affected by the exposure. Changes in the hydrophone
over which the group was most frequently detected occurred as the animals moved around within a foraging bout, and
their number was significantly less the closer the whales were to the sound source. Non-exposed groups also had
significantly more changes in the primary hydrophone than exposed groups irrespective of distance. Our results suggested
that broadband ship noise caused a significant change in beaked whale behavior up to at least 5.2 kilometers away from
the vessel. The observed change could potentially correspond to a restriction in the movement of groups, a period of more
directional travel, a reduction in the number of individuals clicking within the group, or a response to changes in prey
movement.The research reported here was financially supported by the United States (U.S.) Office of Naval Research (www.onr.navy.mil) grants N00014-07-10988,
N00014-07-11023, N00014-08-10990; the U.S. Strategic Environmental Research and Development Program (www.serdp.org) grant SI-1539, the Environmental
Readiness Division of the U.S. Navy (http://www.navy.mil/local/n45/), the U.S. Chief of Naval Operations Submarine Warfare Division (Undersea Surveillance), the
U.S. National Oceanic and Atmospheric Administration (National Marine Fisheries Service, Office of Science and Technology) (http://www.st.nmfs.noaa.gov/), U.S.
National Oceanic and Atmospheric Administration Ocean Acoustics Program (http://www.nmfs.noaa.gov/pr/acoustics/), and the Joint Industry Program on Sound
and Marine Life of the International Association of Oil and Gas Producers (www.soundandmarinelife.org)
Echolocation : clicking for supper
No full textWhen close to prey, porpoises actively widen their sonar beam, which may make it harder for the prey to escape.Peer reviewe
A digital acoustic recording tag for measuring the response of wild marine mammals to sound
No full textDefinitive studies on the response of marine mammals to anthropogenic sound are hampered by the short surface time and deep-diving lifestyle of many species. A novel archival tag, called the DTAG, has been developed to monitor the behavior of marine mammals, and their response to sound, continuously throughout the dive cycle. The tag contains a large array of solid-state memory and records continuously from a built-in hydrophone and suite of sensors. The sensors sample the orientation of the animal in three dimensions with sufficient speed and resolution to capture individual fluke strokes. Audio and sensor recording is synchronous so the relative timing of sounds and motion can be determined precisely. The DTAG has been attached to more than 30 northern right whales (Eubalaena glacialis) and 20 sperm whales (Physeter macrocephalus) with recording duration of up to 12 h per deployment. Several deployments have included sound playbacks to the tagged whale and a transient response to at least one playback is evident in the tag data.Peer reviewe
Beaked whales respond to simulated and actual navy sonar
No full textThis article is distributed under the terms of the Creative Commons Public Domain declaration. The definitive version was published in PLoS One 6 (2011): e17009, doi:10.1371/journal.pone.0017009.Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2–3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2–3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 µPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance.The research reported here was financially supported by the United States (U.S.) Office of Naval Research (www.onr.navy.mil) Grants N00014-07-10988,
N00014-07-11023, N00014-08-10990; the U.S. Strategic Environmental Research and Development Program (www.serdp.org) Grant SI-1539, the Environmental
Readiness Division of the U.S. Navy (http://www.navy.mil/local/n45/), the U.S. Chief of Naval Operations Submarine Warfare Division (Undersea Surveillance), the
U.S. National Oceanic and Atmospheric Administration (National Marine Fisheries Service, Office of Science and Technology) (http://www.st.nmfs.noaa.gov/), U.S.
National Oceanic and Atmospheric Administration Ocean Acoustics Program (http://www.nmfs.noaa.gov/pr/acoustics/), and the Joint Industry Program on Sound
and Marine Life of the International Association of Oil and Gas Producers (www.soundandmarinelife.org)
Dose response severity functions for acoustic disturbance in cetaceans using recurrent event survival analysis
No full textThis work was financially supported by the U. S. Office of Naval Research grant N00014‐12‐1‐0204, under the project “Multi‐study Ocean acoustics Human effects Analysis” (MOCHA). . L. Tyack received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. The case study data were provided by the 3S project, which was funded by the U.S. Office of Naval Research, the Norwegian Ministry of Defense, the Netherlands Ministry of Defense, and WWF Norway.Behavioral response studies (BRSs) aim to enhance our understanding of the behavior changes made by animals in response to specific exposure levels of different stimuli, often presented in an increasing dosage. Here, we focus on BRSs that aim to understand behavioral responses of free-ranging whales and dolphins to manmade acoustic signals (although the methods are applicable more generally). One desired outcome of these studies is dose-response functions relevant to different species, signals and contexts. We adapted and applied recurrent event survival analysis (Cox proportional hazard models) to data from the 3S BRS project, where multiple behavioral responses of different severities had been observed per experimental exposure and per individual based upon expert scoring. We included species, signal type, exposure number and behavioral state prior to exposure as potential covariates. The best model included all main effect terms, with the exception of exposure number, as well as two interaction terms. The interactions between signal and behavioral state, and between species and behavioral state highlighted that the sensitivity of animals to different signal types (a 6–7 kHz upsweep sonar signal [MFAS] or a 1–2 kHz upsweep sonar signal [LFAS]) depended on their behavioral state (feeding or nonfeeding), and this differed across species. Of the three species included in this analysis (sperm whale [Physeter macrocephalus], killer whale [Orcinus orca] and long-finned pilot whale [Globicephala melas]), killer whales were consistently the most likely to exhibit behavioral responses to naval sonar exposure. We conclude that recurrent event survival analysis provides an effective framework for fitting dose-response severity functions to data from behavioral response studies. It can provide outputs that can help government and industry to evaluate the potential impacts of anthropogenic sound production in the ocean.Peer reviewe
An optical telemetry device to identify which dolphin produces a sound
No full textAuthor Posting. © Acoustical Society of America, 1985. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 78 (1985): 1892-1895, doi:10.1121/1.392777.A small telemetry device, called a "vocalight," was designed for attachment to a dolphin's head using a suction cup. The vocalight lights up a variable number of light-emitting diodes depending upon the loudness of sounds received at a hydrophone within the suction cup. If vocalights matched for sensitivity are put on each dolphin within a captive group, observers can identify which dolphin produces a vocalization. Use of vocalights indicates that source levels of whistles from captive bottlenosed dolphins, Tursiops truncatus, range from approximately 125 to over 140 dB re: 1 µPa at 1 m.This research was performed with financial assistance from a W.H.O.I. Postdoctoral Scholar Award and N.I.H. Postdoctoral Fellowship S-F32-NS07206
Sound production and associated behavior of tagged fin whales (Balaenoptera physalus) in the Southern California Bight
No full textBackground: For marine animals, acoustic communication is critical for many life functions, yet individual calling behavior is poorly understood for most large whale species. These topics are important for understanding whale social behavior and can also serve as a baseline for behavioral studies assessing whale response to disturbance. Using a new technique for identifying the calling individual, we measured body orientation, dive behavior, and surface social behavior in relation to call production for tagged fin whales in Southern California. Results: Behavioral metrics associated with elevated call rates included shallow maximum dive depths (10–15 m), little body movement, negative pitch in body orientation, and moderate body roll. Calling whales were also more likely to be traveling than milling, in groups rather than solitary, and without change in group size compared to non-calling whales. Conclusions: These are the first descriptions of body posture and depths at which fin whales are most likely to call, and some possible sound propagation and/or anatomical reasons for these results are considered. The call behavior characterizations presented here will help in predicting calling behavior from surface behavior, informing interpretation of passive acoustic data, and determining the effects of anthropogenic sound on whales in Southern California.Peer reviewe
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