Blar i Articles på emneord "akustikk"
Viser treff 1-20 av 21
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Acoustic abundance estimation of midwater animals
(Journal article; Peer reviewed, 1999) -
Acoustic observations of jellyfish in the Namibian Benguela
(Journal article; Peer reviewed, 2001-01-26)Multi-frequency acoustic data (18, 38 and 120 kHz) were collected in conjunction with pelagic trawl sampling for gelatinous macrozooplankton during a cruise to the Namibian Benguela in September 1999. Sampling focused ... -
Antarctic krill swarm characteristics in the Southeast Atlantic sector of the Southern Ocean
(Journal article; Peer reviewed, 2012-09-28)Knowledge about swarm dynamics and underlying causes is essential to understand the ecology and distribution of Antarctic krill Euphausia superba. We collected acoustic data and key environmental data continuously across ... -
Behavior of individual mesopelagic fish in acoustic scattering layers of Norwegian fjords
(Journal article; Peer reviewed, 2008-05-22)Mesopelagic acoustic scattering layers (SLs) in 2 fjords were studied from a stationary research vessel. Diel vertical movements of SLs were assessed by hull-mounted transducers, while in situ behavior of individuals ... -
Behavioral responses of herring (Clupea harengus) to 1–2 and 6–7 kHz sonar signals and killer whale feeding sounds
(Journal article; Peer reviewed, 2009-01)Military antisubmarine sonars produce intense sounds within the hearing range of most clupeid fish. The behavioral reactions of overwintering herring (Clupea harengus) to sonar signals of two different frequency ranges ... -
Bioacoustics and D. V. Holliday: a scientific tribute
(Others, 2004) -
Can predator avoidance explain varying overwintering depth of Calanus in different oceanic water masses?
(Journal article; Peer reviewed, 1999-04-15)Distributions of overwintering Calanus spp. in the upper 1000 m in the Norwegian and Greenland Seas were studied in relation to hydrography, invertebrate predators and acoustic scattering layers (38 kHz). C, finmarchicus ... -
Can the precision of bottom trawl indices be increased by using simultaneously collected acoustic data? The Barents Sea experience
(Journal article; Peer reviewed, 2007-12)Acoustic data are recorded continuously during the winter survey for demersal fish in the Barents Sea. This paper presents a method for using the information from the acoustic recordings between trawl stations in an attempt ... -
Detecting Atlantic herring by parametric sonar
(Journal article; Peer reviewed, 2010-03-17)The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1–6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools ... -
An effective method for the recapture of escaped farmed salmon
(Journal article; Peer reviewed, 2011-04-04)The search for effective strategies to prevent and mitigate accidental releases of aquaculture fishes is on-going. To test a new recapture strategy and evaluate the individual dispersal behaviour of escaped farmed Atlantic ... -
Hydroacoustic performance of fishery survey instruments
(Others, 2001) -
Lateral-aspect target strength measurements of in situ herring (Clupea harengus)
(Journal article; Peer reviewed, 2009-07)Surveys of schooling herring with the new multi-beam sonar (Simrad MS70) pose new challenges when converting the echo energy to estimates of biomass. Since the sonar projects horizontally, data and models of lateral-aspect ... -
Observations of cod reaction to trawling noise
(Working paper, 1988-04)Observations made from a stationary echo sounder, passed by a trawling vessel, clearly demonstrate the flight reaction of cod as a response to the noise from the vessel. Horizontal dispersal and downward swimming has been ... -
Observing individual fish behavior in fish aggregations: Tracking in dense fish aggregations using a split-beam echosounder
(Journal article; Peer reviewed, 2007)Acoustic instruments are important tools for observing the behavior of aquatic organisms. This paper presents a simple but efficient method for improving the tracking of closely spaced targets using a split-beam echosounder. ... -
Observing the behavioral response of herring exposed to mid-frequency sonar signals. (A)
(Conference object, 2010-03)There is general concern on how mid-frequency military sonars might affect aquatic animals. Approaches used to investigate possible effects on Norwegian spring spawning herring (Clupea harengus) are presented. Experiments ... -
Ocean Acoustic Waveguide Remote Sensing (OAWRS) of marine ecosystems
(Journal article; Peer reviewed, 2009-12-03)Ocean Acoustic Waveguide Remote Sensing (OAWRS) has recently been shown to be capable of instantaneously imaging and continuously monitoring fish populations over continental shelf-scale areas, covering thousands of km2. ... -
Toward a Global Ocean Ecosystem Mid-trophic Automatic Acoustic Sampler (MAAS)
(Journal article; Peer reviewed, 2009-05-26)Despite their huge biomass and pivotal role, the mid-trophic levels of marine ecosystems are not generally subject to systematic monitoring. Data from such monitoring is crucial for parameterizing, validating, and constraining ...