Browsing Published in cooperation with others by Author "Godø, Olav Rune"
Now showing items 1-20 of 63
-
A preliminary report on the migration and recruitment to the commercial stock of Greenland halibut (Reinhardtius hippoglossoides) in the Svalbard area.
Godø, Olav Rune; Haug, Tore (ICES CM Documents;1985/G:18, Working paper, 1985) -
A stationary acoustic system for monitoring undisturbed and vessel affected fish behaviour
Godø, Olav Rune; Totland, Atle (ICES CM Documents;1996/B:12, Working paper, 1996)Thorough knowledge of the dynamics of natural fish behaviour and distribution within a survey and among surveys is fundamental for reliability of time series of abundance indices. Further, vessel/trawl affected avoidance ... -
A three level pelagic trawl for near surface sampling of juvenile fish
Godø, Olav Rune; Valdemarsen, John Willy (ICES CM Documents;1993/B:19, Working paper, 1993)In the northeast Atlantic Ocean catch rates of juvenile fish from pelagic trawls are used to calculate indices of relative abundance which are applied as a first indication of year class strength. A major constraint for ... -
Acoustic estimates of spawning cod off Lofoten and Møre in 1982
Nakken, Odd; Godø, Olav Rune; Raknes, Askjell (ICES CM documents, Working paper, 1982)Acoustic surveys on spawning cod were carried out in Lofoten and off Møre in order to estimate the stock size and structure. The 1975 yearclass made up the bulk of the spawning stock in both areas. In the Lofoten area the ... -
Acoustic estimates of spawning cod off Lofoten and Møre in 1983
Nakken, Odd; Godø, Olav Rune; Raknes, Askjell (ICES CM documents, Working paper, 1983)Acoustic surveys on spawning cod were arried out in Lofoten and off Møre in order to estimate the stock size and structure. The 1975 year class made up the bulk of the spawning stock in both areas. In the Lofoten area the ... -
Acoustic estimates of spawning cod off Lofoten and Møre in 1984
Nakken, Odd; Godø, Olav Rune; Raknes, Askjell (ICES CM documents, Working paper, 1984)Acoustic surveys on northeast Arctic spawning cod were carried out in Lofoten and off Møre in March-April 1984 in order to estimate the stock size and structure. Within the investigated areas the total number at spawning ... -
Acoustic estimates of spawning cod off Lofoten and Møre in 1985
Godø, Olav Rune; Raknes, Askjell; Sunnanå, Knut (ICES CM Documents;1985/G:66, Working paper, 1985)The annual surveys on the spawning stock of North-east Arctic cod were carried out in the Lofoten and Møre areas in March- April 1985. These surveys were undertaken to estimate the size and age structure of the spawning ... -
Analysis of CPUE from the Norwegian bottom trawl fleet
Salthaug, Are; Godø, Olav Rune (ICES CM Documents;2000/W:14, Working paper, 2000)Commercial logbooks with catch and effort data have been collected and recorded by the Norwegian Direcorate of Fisheries since 1971. Annual age segregated CPUE indices are calculated with different methods for North-east ... -
Behavioural rhythm of cod during migration in the Barents Sea
Stensholt, Boonchai K.; Michalsen, Kathrine; Godø, Olav Rune (ICES CM Documents;2000/K:34, Working paper, 2000)To assess fish abundance by direct methods and to understand and model species interaction, it is important to have proper knowledge about behavioural patterns. Patterns in vertical distribution might strongly affect ... -
Blue whiting — a key species in the mid-water ecosystems of the north-eastern Atlantic
Heino, Mikko; Godø, Olav Rune (ICES CM documents, Working paper, 2002)Blue whiting (Micromesistius poutassou) is a mesopelagic gadoid that is widely distributed in northeastern Atlantic from the Canary Island to Spitsbergen. It is abundant and commercially exploited in the Norwegian Seas, ... -
Can subjective evaluation of echograms improve correlation between bottom trawl and acoustic densities?
Godø, Olav Rune; Hjellvik, Vidar; Greig, Tony; Beare, Douglas (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
Hjellvik, Vidar; Godø, Olav Rune; Tjøstheim, Dag (ICES CM documents, Conference object, 2006) -
Catfish - King of the sea
Godø, Olav Rune; Huse, Irene; Michalsen, Kathrine (ICES CM Documents;1995/B:16, Working paper, 1995)During an acoustic tagging experiment on cod in the Barents Sea in March 1995 a hierarchy between different fish species was revealed, and the catfish (Anarhichas sp.) was observed to be dominant in relation to cod and ... -
Changes in acoustic abundance - a signal indicatior for stock dynamics for cod (Gadus morhua)
Godø, Olav Rune; Ona, Egil (ICES CM documents, Working paper, 1999)To be able to take the proper and timely management actions, it is crucial to reliably defect major changes in trends of fish stock abundance. For the assessment of Northeast Arctic cod, the Norwegian bottom trawl survey ... -
Comparison between "underway" and "on station" acoustic measurements made during bottom trawl surveys
Nicolas, Bez; Mireille, Bouleau; Godø, Olav Rune; Armstrong, Mike; Gerritsen, Hans D.; Vérin, Yves; Massé, Jacques; Méhault, Sonia (ICES CM Documents;2002/J:3, Working paper, 2002)It becomes in many cases, routine, to collect acoustic data during bottom trawl surveys, both during and between trawls providing “on station” and “underway” acoustic data. Still, the combination of trawl and acoustic data ... -
Comparison of Northeast Atlantic mackerel (Scomber scombrus) distribution patterns in the Norwegian Sea using lidar, sonar, and trawl
Tenningen, Eirik; Godø, Olav Rune; Iversen, Svein A.; Slotte, Aril; Hjellvik, Vidar; Torkelsen, Terje (ICES CM documents, Working paper, 2003)In July 2002 the Institute of Marine Research (IMR), Bergen mapped the distribution and density of mackerel in the Norwegian Sea using lidar, sonar and trawl. A major objective was to test the efficiency of the lidar as ... -
Day / night variation in fish directivity in the trawl opening
Huse, Ingvar; Aglen, Asgeir; Engås, Arill; Godø, Olav Rune; West, Charles W. (ICES CM Documents;1994/B:18, Working paper, 1994)Still photographs of fish in the mouth area of a bottom trawl were taken by a downwards-oriented automated strobe camera mounted near the headrope. Fish angles relative to the towing direction were measured. Fish were ... -
Density dependent catchability in bottom trawl surveys
Aglen, Asgeir; Engås, Arill; Godø, Olav Rune; McCallum, Barry R.; Stansbury, Don; Walsh, Stephen J. (ICES CM Documents;1997/W:16, Working paper, 1997)Fish form schools, layer or patches in which the individual fish's behaviour is not independent of its neighbours movements. On the other hand, at low densities fish may have the freedom to act as single individuals ... -
Designing an Ocean Mid-trophic Automatic Acoustic Sampler (MAAS) - thoughts on how to include echo sounder observatories in ecosystem models
Handegard, Nils Olav; Domokos, Réka; Godø, Olav Rune; Jouanno, Julien; Kloser, Rudy; Lehodey, Patrick; Maury, Olivier; Senina, Inna (ICES CM documents;2009/I:21, Working paper, 2009)Echo sounders are a widely used tool for observing marine ecosystems. Traditionally, carefully designed surveys are used to integrate biomass to a global estimate, which is coupled to traditional stock assessment models. ... -
Differences between near bottom biomass spatial structure observed in the Irish Sea, the North Sea and the Barents Sea in recent years
Mireille, Bouleau; Nicolas, Bez; Hjellvik, Vidar; Godø, Olav Rune; Reid, David; Beare, Douglas; Greig, Tony; Armstrong, Mike; Gerritsen, Hans D.; Mackinson, Steven; Neville, Suzanna; Kooij, Jeroen van der; Vérin, Yves; Massé, Jacques (ICES CM documents, Working paper, 2003)Based on acoustic data and trawl catches collected during bottom trawl surveys, we compare the spatial structure of the biomass available in the first meters above the bottom in three different regions, the Barents Sea ...