Browsing Brage IMR by Author "Engås, Arill"
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A method to reduce survey bottom trawl variability
Engås, Arill; Ona, Egil (ICES CM Documents;1991/B:39, Working paper, 1991)A technique for limiting the variability of trawl doorspread is described. In addition, modifications of trawling technique which enable the doors to stay upright and maintain constant ground contact under different ... -
A new radio link telemetry positioning system, experiences from tracking of fish and crustaceans
Bjordal, Åsmund; Engås, Arill; Soldal, Aud Vold; Øvredal, Jan Tore (ICES CM Documents;1993/B:23, Working paper, 1993)Telemetry positioning systems based on hydrophone arrays have been used for different tracking applications. The main improvement of this new system is the wire-less transmission of signals from hydrophone - radio buoys ... -
Accuracy of VMS data from Norwegian demersal stern trawlers for estimating trawled areas in the Barents Sea
Skaar, Kristian; Jørgensen, Terje; Ulvestad, Bente Hoddevik; Engås, Arill (Journal article; Peer reviewed, 2011-06-08)The accuracy of vessel monitoring system (VMS) data, used to determine fishing activity in the trawl fishery for gadoids in the Barents Sea, was studied by observer notes and Global Positioning System (GPS) data from two ... -
Acoustic abundance estimation of the stock of Norwegian spring spawning herring, winter 1995- 1996
Foote, Kenneth G.; Ostrowski, Marek; Røttingen, Ingolf; Engås, Arill; Hansen, Kaare A.; Hauge, Kjellrun Hiis; Skeide, Roar L.; Slotte, Aril; Torgersen, Øyvind (ICES CM Documents;1996/H:33, Working paper, 1996)Standard echo integration methodology has been applied to the stock of Norwegian spring spawning herring (Clupea harengus) wintering in the Ofotfjord-Tysfjord-Vestfjord system during late autumn 1995 and early winter ... -
Avoidance reactions of ultrasonic tagged cod during bottom trawling in shallow water
Engås, Arill; Soldal, Aud Vold; Øvredal, Jan Tore (ICES CM Documents;1991/B:41, Working paper, 1991)Introduction: Observations made by echo sounder (Ona 1988) have shown that cod (Gadus morhua L.) may avoid an approaching survey vessel horizontally and vertically. However, there has been a lack of information on the ... -
Behavior-dependent selectivity of yellowtail flounder (Limanda ferruginea) in the mouth of a commercial bottom trawl
Underwood, Melanie; Winger, Paul D.; Fernø, Anders; Engås, Arill (Journal article; Peer reviewed, 2015-09-02)To improve the efficiency of a commercial bottom trawl for catching yellowtail flounder (Limanda ferruginea), we studied the behavior of individuals in the middle of the trawl mouth. Observations were conducted with ... -
Catch comparison between rockhoppers and bobbins ground gear on the Norwegian bottom sampling trawl
Engås, Arill; Jacobsen, Jan Arge; Soldal, Aud Vold (ICES CM Documents;1988/B:31, Working paper, 1988)In a study aimed at improving the reliability of the Norwegian bottom sampling trawl, comparative fishing between standard bobbins gear and rockhopper ground gear were carried out in the Barents Sea. The catch ratios ... -
Collecting size-selectivity data for Antarctic krill (Euphausia superba) with a trawl independent towing rig
Krag, Ludvig Ahm; Krafft, Bjørn Arne; Engås, Arill; Herrmann, Bent (Peer reviewed; Journal article, 2018)For the development of efficient trawls to minimize catch loss, escape mortality and potential negative ecosystem impacts from the fishery, the understanding about trawl selectivity processes are crucial. Small crustaceans ... -
CRISP- Toktrapport. Testing trålutstyr og instrumentering. G. O. Sars 1.-11. mars 2015
Valdemarsen, John Willy; Øvredal, Jan Tore; Aasen, Asbjørn; Engås, Arill; Rosen, Shale; Macaulay, Gavin; Mæstad, Odd Kjartan; Sæstad, Arvid; Nedrebø, Trond; Bærhaugen, Thor; Vågstøl, Håvard; Knotten, Vidar (Rapport fra havforskningen;10-2016, Research report, 2016) -
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 ... -
Day and night fish distribution pattern in the net mouth area of the Norwegian bottom-sampling trawl
Engås, Arill; Ona, Egil (Journal article; Peer reviewed, 1990)A high-frequency scanning sonar, mounted as a net sonde, was used to study fish behaviour in the mouth area of the Norwegian bottom-sampling trawl. Fish distribution patterns were significantly different by day and night. ... -
Deep Vision: An In-Trawl Stereo Camera Makes a Step Forward in Monitoring the Pelagic Community
Underwood, Melanie J.; Rosen, Shale; Engås, Arill; Eriksen, Elena (Journal article; Peer reviewed, 2014-11-13)Ecosystem surveys are carried out annually in the Barents Sea by Russia and Norway to monitor the spatial distribution of ecosystem components and to study population dynamics. One component of the survey is mapping the ... -
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 ... -
Development of a species-selective trawl for demersal gadoid fisheries
Engås, Arill; West, Charles W. (ICES CM Documents;1995/B+G+H+J+K:1, Working paper, 1995)An experiment was carried out to test a prototype species-selective bottom trawl for separating cod from haddock, secondarily saithe, in the Norwegian commercial roundfish fisheries. A sorting system incorporating a ... -
Diurnal changes in bottom trawl catches and vertical fish distribution
Engås, Arill; Jacobsen, Jan Arge; Soldal, Aud Vold (ICES CM Documents;1988/B:32, Working paper, 1988)Bottom sampling trawl catches and acoustic abundance estimates of North-East Arctic cod and haddock in the Barents Sea were collected and examined according to time of day. The trawl catches were at average larger by day ... -
Effects of seismic shooting on catch and catch-availability of cod and haddock
Engås, Arill; Løkkeborg, Svein; Ona, Egil; Soldal, Aud Vold (Fisken og havet, Research report, 1993) -
Effects of seismic shooting on local abundance and catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)
Engås, Arill; Løkkeborg, Svein; Ona, Egil; Soldal, Aud Vold (Journal article; Peer reviewed, 1996)To determine whether seismic exploration affected abundance or catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus), acoustic mapping and fishing trials with trawls and longlines were conducted in the ... -
Effekter av seismisk skyting på fangst og fangsttilgjengelighet av torsk og hyse
Engås, Arill; Løkkeborg, Svein; Ona, Egil; Soldal, Aud Vold (Fisken og havet, Research report, 1993) -
Employing a trawl independent multi-compartment towing rig to study selectivity of crustaceans in trawls
Krag, Ludvig Ahm; Krafft, Bjørn Arne; Engås, Arill; Herrmann, Bent (Conference object, 2016-09-22) -
Experiences using the constraint technique on bottom trawl doors
Engås, Arill; Ona, Egil (ICES CM Documents;1993/B:18, Working paper, 1993)The constraint technique, i.e. using a rope between the warps, has the intention of minimizing the variability in trawl geometry with depth. Experiments with the constraint technique on two different bottom trawls used ...