Browsing Brage IMR by Author "Godø, Olav Rune"
Now showing items 41-60 of 140
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Diurnal variation in acoustic densities: why do we se less in the dark?
Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (ICES CM Documents;2004/R:33, Working paper, 2004)Introduction: In the Barents Sea, the echo abundance of demersal fish is about 50% higher at day than at night. Three possible reasons are: • Fish hide in the bottom dead zone at night. • Fish target strength changes due ... -
Diurnal variation in acoustic densities: why do we see less in the dark?
Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (Journal article; Peer reviewed, 2005)Diurnal fluctuations in total integrated echo abundance and in vertical density profiles were examined using data from the Norwegian combined acoustic and bottom-trawl survey for demersal fish during winter in the ... -
Diurnal variation in bottom trawl survey catches: does it pay to adjust?
Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (ICES CM Documents;2001/Q:11, Working paper, 2001)We have studied the diurnal bias of bottom trawl survey catches with the purpose of adjusting for it and thereby improving the accuracy of abundance estimates. The correction term is estimated with uncertainty, and thus ... -
Diurnal variation in bottom trawl survey catches: does it pay to adjust?
Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (Journal article; Peer reviewed, 2002)The diurnal bias of bottom trawl survey catches is studied with the purpose of adjusting for it and thereby improving the accuracy of abundance estimates. The correction term is estimated with uncertainty and thus ... -
Diurnal variation in frequency response of gadoids in the Barents Sea
Godø, Olav Rune; Hjellvik, Vidar; Tjøstheim, Dag (ICES CM documents, Working paper, 2006)Earlier studies have demonstrated substantial diurnal variation in acoustic abundance of fish. Both the level and the uncertainty of abundance estimates from surveys carried out around the clock are affected. It has been ... -
The effect of attenuation from fish on passive detection of sound sources in ocean waveguide environments
Duane, Daniel; Zhu, Chenyang; Piavsky, Felix; Godø, Olav Rune; Makris, Nicholas C. (Peer reviewed; Journal article, 2021)Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range passive sensing of manmade vehicles, geophysical phenomena, and vocalizing marine life. The effect ... -
Estimates of stock size of Northeast Arctic cod and haddock from survey data 1986/1987
Godø, Olav Rune; Hylen, Arvid; Jacobsen, Jan Arge; Jakobsen, Tore; Mehl, Sigbjørn; Nedreaas, Kjell Harald; Sunnanå, Knut (ICES CM documents, Working paper, 1987)Combined acoustic and bottom trawl survey for cod and haddock were carried out in the Svalbard area in autumn 1986 and in the Barents Sea during the winter 1987. An acoustic survey for spwaning cod was carried out in March ... -
Evaluation of Antarctic krill biomass and distribution off the South Orkney Islands 2011-2015
Skaret, Georg; Krafft, Bjørn Arne; Calise, Lucio; Watkins, J; Pedersen, Ronald; Godø, Olav Rune (;WG-EMM-15/54, Research report, 2015-06-22)Annual acoustic trawl surveys for krill monitoring have been carried out by the Institute of Marine research, Norway near the South Orkney Islands since 2011. The survey has been conducted early in the fishing season ... -
Exploitation of Antarctic krill Euphausia superba by three air-breathing predators with contrasting foraging strategies – implications for fisheries feedback management
Lowther, Andrew D.; Godø, Olav Rune; Kovacs, Kit; Krafft, Bjørn Arne; Lydersen, Christian; Staniland, Iain; Trathan, Phil; Watkins, Jon l (Conference object, 2016)SCAR Open Science Conference, Kuala Lumpur 2016 -
Field methods for fish behaviour studies used in Norway
Bjordal, Åsmund; Godø, Olav Rune (PINRO-IMR Symposium, Conference object, 1997) -
Fish behaviour during sampling as observed from free floating buoys - application for bottom trawl survey assessment
Godø, Olav Rune; Somerton, David; Totland, Atle (ICES CM documents, Working paper, 1999)Varying fish distribution and behaviour during bottom trawl surveys has long been considered important for the reliability of survey abundance estimates. Size and species dependent behaviour may bias the estimates and ... -
Fish reaction to trawling noise: The significance for trawl sampling
Ona, Egil; Godø, Olav Rune (Conference object, 1990)The reactions of fish during trawling were observed with a stationary echo sounder as a trawling vessel passed close to the transducer. Several strong, downward avoidance reactions of haddock (Melanogrammus aeglefinus ) ... -
Fisheries-induced evolution in cod
Heino, Mikko; Godø, Olav Rune; Dieckmann, Ulf (ICES CM documents;2010/M:24, Working paper, 2010)Over the last eight decades, northeast Arctic cod has shown a marked change towards earlier maturation at smaller sizes. At the same time, harvesting shifted from primarily targeting mature cod in the spawning grounds to ... -
Fisheries-induced evolution in cod
Heino, Mikko; Godø, Olav Rune; Dieckmann, Ulf (ICES CM documents;2010/M:24, Working paper, 2010)Over the last eight decades, northeast Arctic cod has shown a marked change towards earlier maturation at smaller sizes. At the same time, harvesting shifted from primarily targeting mature cod in the spawning grounds to ... -
Fiskeåtferd og prøvetaking
Godø, Olav Rune; Totland, Atle (Rapport fra senter for marine ressurser;Nr. 4 - 1993, Working paper, 1993-04) -
A flexible autonomous robotic observatory infrastructure for bentho-pelagic monitoring
Aguzzi, Jacopo; Albiez, Jan; Flögel, Sascha; Godø, Olav Rune; Grimsbø, Endre; Marini, Simone; Pfannkuche, Olaf; Rodriguez, Erik; Thomsen, Laurenz; Torkelsen, Terje; Valencia, Javier; López-vázquez, Vanesa; Wehde, Henning; Zhang, Guosong (Peer reviewed; Journal article, 2020)This paper presents the technological developments and the policy contexts for the project “Autonomous Robotic Sea-Floor Infrastructure for Bentho-Pelagic Monitoring” (ARIM). The development is based on the national ... -
Fordeling og relativ mengde av norsk arktisk torsk, hausten 1990.
Mehl, Sigbjørn; Godø, Olav Rune; Korsbrekke, Knut ([Toktrapport/Havforskningsinstituttet];, Working paper, 1991) -
Foreløpige resultater av merkeforsøk på kysttorsk i området Møre-Helgeland.
Godø, Olav Rune (Fisken og havet, Research report, 1983)Results from previous tagging experiments at the Møre-Helgeland coast in 1956, 1957 and 1964 indicated negligible mingling between the coastal cod populations at the Møre and Helgeland coast, but some migration from ... -
Forskjeller i gytepopulasjonane av norsk-arktisk torsk på Mørekysten og i Lofoten
Godø, Olav Rune (Fisken og havet, Research report, 1983)The yields in the Møre and Lofoten skrei fisheries have varied independantly, i.e, good yields in one spawning area do not necessarily coincide with good yields in the other. Tagging results from the two areas have ... -
Fremtidsmetodar: Teknologi og fiskeriforskning
Ona, Egil; Godø, Olav Rune (Havforskningstema, Working paper, 2004)