Blar i Brage IMR på forfatter "Dalen, John"
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Forsøk med akustiske merker i Barentshavet vinteren 1975
Dalen, John (Fisken og havet;1975 - Nr.2, Research report, 1975)Experiments on acoustic tagging on cod took place in a limited area of the Barents Sea in February 1975. The work was done during a survey with R.V. «G.O. Sars» when looking for the distribution, abundance and size composition ... -
Forsøk med akustiske merker i Lofoten i mars 1974
Dalen, John (Fisken og havet, Research report, 1974)Introductory experiments on acoustic tagging were carried out on cod in Lofoten in March 1974. The research vessel used 'was «G. O. Sars» because of her excellent sonar equipment. Two fishes were tagged. The tags used ... -
Ikkje skadeleg for bestandane [debattinnlegg i Fiskeribladet Fiskaren]
Misund, Ole Arve; Dalen, John; Løkkeborg, Svein; Olsen, Erik (Others, 2008-05-28) -
The influence of wind-induced bubbles on echo integration surveys
Løvik, Arne; Dalen, John (Journal article, 1981)An investigation of attenuation of acoustic energy caused by gas bubbles in the surface layers has been carried out. This was done primarily to study the effect on echo integration of fish abundance when using hull-mounted ... -
Investigations on demersal fish in the Barents Sea in winter 1977
Dalen, John; Hylen, Arvid; Smedstad, Odd M. (ICES CM Documents;1977/F:23, Working paper, 1977) -
Kunnskapsstatus og forskningsbehov med hensyn til skremmeeffekter og skadevirkninger av seismiske lydbølger på fisk og sjøpattedyr : rapport til Oljedirektoratet, Fiskeridirektoratet og Statens forurensningstilsyn fra spesielt nedsatt forskergruppe
Dalen, John; Hovem, Jens Martin; Karlsen, Hans Erik; Kvadsheim, Petter H.; Løkkeborg, Svein; Mjelde, Rolf; Pedersen, Audun; Skiftesvik, Anne Berit (Research report, 2008) -
Loddeundersøkelser i Barentshavet i mai - juni 1974
Dalen, John; Dommasnes, Are (Fisken og havet, Research report, 1974)During May—June 1974 observations were made on the distribution, abundance and year-class composition of capelin in the Barents Sea. Good concentrations of capelin were found over a considerably larger area than at the ... -
Loddeundersøkelser i Barentshavet i september-oktober 1974
Buzeta, Ramon; Dalen, John; Dommasnes, Are; Hamre, Johannes; Nakken, Odd (Fisken og havet, Research report, 1975)During September-October 1974 observations were made on the distribution, abundance and year-class composition of capelin in the Barents Sea. Specifically it was of great importance to get an abundance estimate of the 1975 ... -
Marinøkologiske ringvirkninger av vindmølleparker til havs
Steen, Henning; Nilssen, Kjell Tormod; Agnalt, Ann-Lisbeth; Alvsvåg, John; Asplin, Lars; Jelmert, Anders; Dahl, Einar; Dalen, John (Fisken og havet, Research report, 2008)There is an increasing need for energy. Considerable efforts are being made to develop environmentally friendly energy sources. Generating electric energy using wind turbines is one of the methods that has gained widespread, ... -
Measurements of Target stength and Spatial Orientation of Euphausiids (krill).
Dalen, John; Kristensen, Åge (ICES CM Documents;1981/B:l7, Working paper, 1981) -
Monitoring fish communities at drifting FADs: an autonomous system for data collection in an ecosystems approach
Brehmer, Patrice; Sancho, Gorka; Josse, Erwan; Taquet, Marc; Georgakarakos, Stratis; Itano, David; Moreno, Gala; Palud, Pierre; Trygonis, Vasilis; Aumeeruddy, Riaz; Girard, Charlotte; Peignon, Christophe; Dalen, John; Dagorn, Laurent (ICES CM documents;2009, Theme session I, Working paper, 2009)An increasing proportion of landings by tuna purse seine fishing vessels are taken around drifting Fish Aggregating Devices (FADs). Although these FADs and their use by the fishing industry to capture tropical tuna have ... -
Multibrukssystem for tauete farkoster og droppsonde - forprosjekt: evaluering av operasjoner, teknologi og systemer med utgangspunkt i måle- og observasjonsbehov
Dalen, John; Knudsen, Hans Petter; Knutsen, Tor; Vedeler, Terje; Melle, Webjørn (Fisken og havet, Research report, 2001)I hovedprosjektet skal det utvikles et integrert system av to tauete farkoster og en droppsonde med sine målesystemer, sensorer og kommunikasjonsgrensesnitt for dataoverføring som i stor grad bruker felles teknologi for ... -
Norwegian investigations on young cod and haddock in the Barents Sea during the winter 1982
Dalen, John; Hylen, Arvid; Nakken, Odd; Randa, Kjell; Smedstad, Odd M. (ICES CM documents, Working paper, 1982)An acoustic survey and a bottom trawl survey were carried out in the Barents Sea during winter 1982. Both surveys showed that there has been a reduction in the total number of cod of about 50% and about 75% for haddock in ... -
On the application of the echointegration method
Dalen, John; Nakken, Odd (ICES CM documents;1983/B:19, Working paper, 1983)The echo integration method used by the Institute of Marine Research is described. The model which are used to convert acoustic abundance indices into fish densities using length and species dependant conversion factors, ... -
Planktonforekomster over Svalbardbanken om vinteren: Akustiske registreringer og video-opptak fra en fjernstyrt undervannsfarkost (ROV)
Knutsen, Tor; Melle, Webjørn; Hassel, Arne; Dalen, John (Interne notat, Working paper, 1997)I forbindelse med konsekvensanalysen før eventuell oljeleting innenfor området Barentshavet-Nord er det gjennomført feltundersøkelser for å avdekke om det er et vesentlig gytefelt for polartorsk i Barentshavet. Undersøkelsene ... -
Preliminary report of the Norwegian investigations on young cod and haddock in the Barents Sea during the winter 1982
Nakken, Odd; Dalen, John; Hylen, Arvid; Randa, Kjell; Smedstad, Odd M. (ICES CM documents, Working paper, 1983)An acoustic survey and a bottow trawl survey for cod and haddock were carried out in the Barents Sea during the winter 1983. The two surveys gave different results. The acoustic survey showed a 50 % reduction from 1982 for ... -
Preliminary reports of the Norwegian investigations on young cod and haddock in the Barents Sea during the winter 1984
Nakken, Odd; Dalen, John; Hylen, Arvid; Randa, Kjell; Jakobsen, Tore (ICES CM documents, Working paper, 1984)An acoustic survey and a bottom trawl survey for cod and haddock were carried out in the Barents Sea during the winter 1984. The two surveys gave different results, both in absolute terms and when changes from the 1983 ... -
Reaction of sandeel to seismic shooting: a field experiment and fishery statistics study
Hassel, Arne; Knutsen, Tor; Dalen, John; Skaar, Kristian; Østensen, Øivind; Haugland, Eli Kyrkjebø; Fonn, Merete; Høines, Åge S.; Misund, Ole Arve (Fisken og havet, Research report, 2003)The reaction to seismics of lesser sandeel (Ammodytes marinus) was investigated in the North Sea using steel cages to enclose the fish while burried in the sand. Three cages were exposed to seismic shooting from SV "Falcon ... -
Relationships between the geometric dimensions and biomass of schools
Misund, Ole Arve; Aglen, Asgeir; Beltestad, Arvid K.; Dalen, John (ICES CM Documents;1990/B:41, Working paper, 1990)Acoustic measurements of the geometric dimensions and packing density of herring, sprat and saithe schools have been conducted by multi-beam sonars and echo integrator systems. Relationships between the reflected echo ... -
Seismikkens ringvirkninger : The impact of seismic surveys
Dalen, John; Mæstad, Kjartan (Havforskningsnytt, Working paper, 2008)Sound is an important means of communication for many species of fish, in terms of feeding, survival and reproduction. The sound waves from seismic guns have low frequencies that overlap the range at which fish hear well. ...