Browsing Brage IMR by Author "Dalen, John"
Now showing items 1-20 of 55
-
Acoustic estimation of size distribution and abundance of zooplankton
Kristensen, Åge; Dalen, John (Journal article; Peer reviewed, 1986)A series of investigations were undertaken to observe and describe the sound backscattering process from larger zooplankton (euphausiids). The target strength versus frequency, size, and aspect angle of the organism was ... -
Acoustic fish data analysis and recommendations related to survey procedures and acoustic data acquisition.
Dalen, John (Rapport/Notat Fysisk oseanografi, Working paper, 1987)During 5 to 23 February 1987 a consultancy was performed in La Goulette, Tunis for the "Tunisian-German Fisheries Project" on behalf of the Deutsche Gesellschaft für Technische Zusammenarbeid GmbH (GTZ) and the Institut ... -
Acoustic method for estimating absolute abundance of young cod and haddock in the Barents Sea
Dalen, John; Smedstad, Odd M. (ICES CM documents, Working paper, 1979) -
Acoustic survey of deep-water fish of the Skagerrak
Bergstad, Odd Aksel; Gordon, John D.M.; Dalen, John (ICES CM Documents;1992/H:15, Working paper, 1992)Introduction: Two fish species, the greater silver smelt Argentina silus and the roundnose grenadier Coryphaenoides rupestris, are highly abundant in the deep-water areas of the Skagerrak. Since the 1970s, a small aimed ... -
Akustisk mengdemåling av torsk og hyse i Barentshavet i februar 1976
Dalen, John; Hylen, Arvid; Smedstad, Odd M. (Fisken og havet, Research report, 1977)From l to 20 February observations of cod and haddock were carried out by R.V. "G.O. Sars" in the centra1 and eastern part of the Barents Sea. The survey was part of a program with the aim of estimating the abundance of ... -
Bunnfiskundersøkelser i Barentshavet vinteren 1977
Dalen, John; Midttun, Lars; Rørvik, Carl Jakob; Smedstad, Odd M. (Fisken og havet, Research report, 1977)This report describes the results from a survey on demersal fish in the Barents Sea from 16 January to 4 February 1977. The work was carried out by two vessels, R.V. "Johan Hjort" which covered the area from a line along ... -
Bunnfiskundersøkelser i Barentshavet vinteren 1978
Dalen, John; Smedstad, Odd M. (Fisken og havet, Research report, 1979)This report describes the results from a survey on demersal fish in the Barents Sea from 30 January to 15 March 1978. The work was carried out by R.V. "G.O.Sars". Maps and tables are presented which show the hydrographic ... -
Bunnfiskundersøkelser ved Bjørnøya og Vest-Spitsbergen høsten 1976
Dalen, John; Rørvik, Carl Jakob; Smedstad, Odd M. (Fisken og havet, Research report, 1977)This report describes the results from a survey with R.V. "G.O. Sars" from 4 October to 8 November on demersal fish in the area of Bear Island and West-Spitsbergen. The most numerous species in the trawl catches were ... -
Bunnfiskundersøkelser ved Bjørnøya og Vestspitsbergen høsten 1977
Dalen, John; Smedstad, Odd M. (Fisken og havet, Research report, 1978)This report describes the results from a survey with R.V. "G.O.Sars" from 10 October to 5 November 1977 on demersal fish in the area off Bear Island and West-Spitsbergen. The most abundant species in the trawl catches ... -
Characteristics of sardinella aggregations in Angolan waters
Dalen, John; Misund, Ole Arve; Luyeye, Nkosi; Boyer, D.; Coetzee, Janet; Cloete, Rudi; Oechslin, Gerhard (ICES CM documents, Working paper, 1998) -
Comparative studies of theoretical and empirical target-strength models of euphausiids (krill) in relation to field-experiment data
Dalen, John; Kristensen, Kurt-Even (Conference object, 1990)The authors considered complete and truncated fluid-sphere models, an approximate fluid-sphere model, complete and truncated fluid finite-length cylinder models, and an empirical model considered as a hybrid fluid bubble/fluid ... -
Deep towed vehicle for fish abundance estimation concept and testing
Dalen, John; Bodholt, Helge (ICES CM Documents;1991/B:53, Working paper, 1991)A research program was initiated in Norway in 1988 for measuring the abundance of fish resources at depth from 500 to 1000 metres. It was decided to develope a deep towed vehicle, to bring acoustic transducers down to ... -
Density in sub-arctic zooplankton
Falk-Petersen, Stig; Køgeler, J. W.; Kristensen, Åge; Pettersen, Fritz; Dalen, John (ICES CM documents, Working paper, 1985)Seasonal variations in specific density were measured for Thysanoessa inermis, Thysanoessa raschii, Meganyctiphanes norvegica, Calanus finmarchicus and Calanus hyperboreus. The density of a 20 mm T. inermis was lowest in ... -
Effects of sound from seismic surveys on fish reproduction, the management case from Norway
Sivle, Lise Doksæter; de Jong, Karen; Vereide, Emilie Hernes; Forland, Tonje Nesse; Wehde, Henning; Dalen, John (Peer reviewed; Journal article, 2021)Anthropogenic noise has been recognized as a source of concern since the beginning of the 1940s and is receiving increasingly more attention. While international focus has been on the effects of noise on marine mammals, ... -
Effektar av luftkanonseismikk på larvar og yngel til havs
Dalen, John (Rapport fra senter for marint miljø, Working paper, 1993)Klarlegge sannsynlege gradar av overlapping mellom skaderisikovolumet rundt luftkanonfelt og opphaldsvolumet for larvar, og framskaffe forhold mellom naturleg neddøying og neddøying pga luftkanonseismikk. -
Effektar av luftkanonskyting på egg, larvar og yngel
Dalen, John (Rapport fra senter for marint miljø, Working paper, 1993)Hovudmålsetninga har vore å fremskaffe nye og supplerande kunnskaper for eit breiare fagleg grunnlag omkring skadeeffektar på egg, larvar og yngel frå seismisk arbeid med luftkanoner. Dette skal medverke til å styrke ... -
Effekter av luftkanonskyting på egg, larver og yngel. Undersøkelser ved Havforskningsinstituttet og Zoologisk laboratorium, UIB
Booman, Clelia; Dalen, John; Leivestad, Helge; Levsen, Arne; van der Meeren, Terje; Toklum, Kjell (Fisken og havet, Research report, 1996)I dette prosjektet har vi utført forsøk med egg, plommesekklarver, larver, postlarver og yngel av fem arter i forbindelse med luftkanonskyting. Deretter har vi observert hvilke effekter dette måtte få for klekkesuksess ... -
Effekter av seismiske undersøkelser på fiskefordeling og fangstrater for garn og line i Vesterålen sommeren 2009 : Effects of seismic surveys on fish distribution and catch rates of gillnets and longlines in Vesterålen in summer 2009
Løkkeborg, Svein; Ona, Egil; Vold, Aud; Peña, Hector; Salthaug, Are; Totland, Bjørn; Øvredal, Jan Tore; Dalen, John; Handegard, Nils Olav (Fisken og havet, Research report, 2010-02-22)In connection with the Norwegian Petroleum Directorate’s seismic survey off the coasts of Vesterålen in summer 2009, a project was carried out to study the degree to which commercial fishes were affected. Four chartered ... -
First data from sea trials with the new MS70 multibeam sonar
Ona, Egil; Dalen, John; Knudsen, Hans Petter; Patel, Ruben; Andersen, Lars Nonboe; Berg, Sverre (Journal article; Peer reviewed, 2006) -
Forsøk med akustiske merker i Barentshavet vinteren 1975
Dalen, John (Fisken og havet, 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 ...