Browsing Havforskningsinstituttet by Subject "akustikk"
Now showing items 41-60 of 286
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Akustiske undersøkelser i Risør- og Kragerøområdet på den norske Skagerrakkysten
(Rapport fra forskningsstasjonen Flødevigen;1993 Nr.2, Working paper, 1993) -
An acoustic survey on 0-group gadoids in the northern North Sea and the Shetland-Orkney area, July 1984
(ICES CM Documents;1985/G:17, Working paper, 1985)An acoustic survey was carried out by two research vessels in July 1984 to assess the distribution and abundance of 0-group gadoids. The 0-groups were distributed in scattering layers by night and in schools by day. ... -
Analysis of spatial variability of Georges Bank haddock (Melanogrammus aeglefinus) from trawl survey data using a linear regression model with spatial interaction
(ICES CM Documents;1990/D:36, Working paper, 1990)A regression model with spatially autocorrelated errors is used to test if there is systematic spatial variation across the study area in haddock catch per tow data from the NEFC annual fall survey from 1963 - 1987. A ... -
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 ... -
Assigning values of target strength and equivalent beam angle in acoustic surveys of fish
(ICES CM Documents;1991/B:34, Working paper, 1991)Contrary to popular opinion, the equivalent beam angle (~) is not determined solely by the transducer directivity. Rather, like the target strength TS, it also depends on the scattering properties of the target fish, but ... -
Automatic recording of fish heart rate on a personal computer
(ICES CM Documents;1988/B:34, Working paper, 1988)From acoustic tags operated into fish in a closed system, the heartbeat signals are sent via underwater telemetry and counted on a personal computer. The computer removes false pulses caused by noise, and calculates the ... -
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 ... -
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) -
Botnfiskundersøkingar i Barentshavet (norsk sone) vinteren 1997
(Fisken og havet, Research report, 1997)Eit kombinert akustikk- og botntråltokt med sikte på å kartleggja utbreiing, mengde og vekst hos torsk, hyse, blåkveite og uerartene er gjennomført sidan 1981 i Barentshavet. Vinteren 1997 vart dekkinga svært mangelfull ... -
Botnfiskundersøkingar i Barentshavet (redusert område) vinteren 1998
(Fisken og havet, Research report, 1998)A combined acoustic and bottom trawl survey to obtain indices of abundance and estimates of length and weight at age has been carried out each winter (4-6 weeks in January- March) since 1981 in the Barents Sea. The target ... -
Botnfiskundersøkingar i Barentshavet vinteren 1996
(Fisken og havet, Research report, 1996)A combined acoustic and bottom trawl survey to obtain indices of abundance and estimates of length and weight at age has been carried out each winter (4-6 weeks in January- March) since 198 1 in the Barents Sea. The ... -
Botnfiskundersøkingar i Barentshavet vinteren 1999
(Fisken og havet, Research report, 1999)A combined acoustic and bottom trawl survey to obtain indices of abundance and estimates of length and weight at age has been carried out each winter (4-6 weeks in January- March) since 1981 in the Barents Sea. The ... -
Bunnfiskundersøkelser i Barentshavet sommeren 1995
(Fisken og havet, Research report, 1996)The report presents the results from the first in a series of surveys which the Institute of Marine Research (IMR) has inititated in order to monitor the stocks of demersal fish in the Barents Sea area. The survey was ... -
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 subjective evaluation of echograms improve correlation between bottom trawl and acoustic densities?
(ICES CM documents, Working paper, 2004)Direct comparison of acoustic densities and trawl catches involves fundamental difficulties related to species and size selectivity of the trawl and efficiency of the acoustic instrumentation. In some surveys, therefore, ... -
Can the precision of bottom trawl indices be increased by using simultaneously collected acoustic data? The Barents Sea experience
(ICES CM documents, Conference object, 2006)