Browsing Articles by Author "Knutsen, Tor"
Now showing items 1-20 of 24
-
An Antarctic krill (Euphausia superba) hotspot: population characteristics, abundance and vertical structure explored from a krill fishing vessel
Krafft, Bjørn Arne; Skaret, Georg; Knutsen, Tor (Journal article; Peer reviewed, 2015-06-17) -
Antarctic krill swarm characteristics in the Southeast Atlantic sector of the Southern Ocean
Krafft, Bjørn A.; Skaret, Georg; Knutsen, Tor; Melle, Webjørn; Klevjer, Thor A.; Søiland, Henrik (Journal article; Peer reviewed, 2012-09-28)Knowledge about swarm dynamics and underlying causes is essential to understand the ecology and distribution of Antarctic krill Euphausia superba. We collected acoustic data and key environmental data continuously across ... -
Broadband echo spectra from euphausiids and copepods
Foote, Kenneth G.; Knutsen, Tor; Atkins, Philip R.; Bongiovanni, Claire; Francis, David T. I.; Eriksen, Peter K.; Larsen, Mette Torp; Mortensen, Tom (Others, 2000) -
Coincident mass occurrence of gelatinous zooplankton in Northern Norway
Knutsen, Tor; Hosia, Aino; Falkenhaug, Tone; Skern-Mauritzen, Rasmus; Wiebe, Peter H.; Larsen, Roger B.; Aglen, Asgeir; Berg, Erik (Peer reviewed; Journal article, 2018)In autumn 2015, several sources reported observations of large amounts of gelatinous material in a large north Norwegian fjord system, either caught when trawling for other organisms or fouling fishing gear. The responsible ... -
Comparison of two multiple plankton samplers: MOCNESS and Multinet Mammoth
Strand, Espen; Broms, Cecilie Thorsen; Bagøien, Espen; Knutsen, Tor; Arnesen, Hilde; Mozfar, Bahar (Peer reviewed; Journal article, 2022)To ensure an optimal continuation of a long time series of zooplankton monitoring surveys, two types of equipment for depth-stratified mesozooplankton sampling were compared. The Institute of Marine Research (Norway) has ... -
A deep scattering layer under the North Pole pack ice
Snoeijs-Leijonmalm, Pauline; Gjøsæter, Harald; Ingvaldsen, Randi Brunvær; Knutsen, Tor; Korneliussen, Rolf; Ona, Egil; Skjoldal, Hein Rune; Stranne, Christian; Mayer, Larry; Jakobsson, Martin; Gårdfeldt, Katarina (Peer reviewed; Journal article, 2021)The 3.3 million km2 marine ecosystem around the North Pole, defined as the Central Arctic Ocean (CAO), is a blind spot on the map of the world’s fish stocks. The CAO essentially comprises the permanently ice-covered deep ... -
Distribution of rorquals and Atlantic cod in relation to their prey in the Norwegian high Arctic
Solvang, Hiroko K.; Haug, Tore; Knutsen, Tor; Gjøsæter, Harald; Bogstad, Bjarte; Hartvedt, Siri; Øien, Nils; Lindstrøm, Ulf (Peer reviewed; Journal article, 2021)Recent warming in the Barents Sea has led to changes in the spatial distribution of both zooplankton and fish, with boreal communities expanding northwards. A similar northward expansion has been observed in several rorqual ... -
Dynamics of phytoplankton species composition, biomass and nutrients in the North Atlantic during spring and summer - A trans-Atlantic study
Naustvoll, Lars Johan; Melle, Webjørn Raunsgård; Klevjer, Thor A.; Drinkwater, Kenneth F.; Strand, Espen; Knutsen, Tor (Peer reviewed; Journal article, 2020)During a return trip in May–June 2013 from Bergen, Norway, to Nuuk, Greenland, on the Institute of Marine Research's R/V “G. O. Sars”, four ocean basins, the Norwegian, Iceland, Irminger and Labrador seas, were surveyed ... -
Ecology of mesozooplankton across four North Atlantic basins
Strand, Espen; Klevjer, Thor A.; Melle, Webjørn Raunsgård; Knutsen, Tor (Peer reviewed; Journal article, 2020)A comparative study of the mesozooplankton in four North Atlantic basins is presented. During a trans-Atlantic expedition with R/V G.O. Sars in May and June 2013, the Norwegian Sea, Iceland Sea, Irminger Sea and Labrador ... -
Evidence of diel vertical migration of mesopelagic sound-scattering organisms in the Arctic
Gjøsæter, Harald; Wiebe, Peter H.; Knutsen, Tor; Ingvaldsen, Randi Brunvær (Peer reviewed; Journal article, 2017) -
Feeding ecology of Benthosema glaciale across the North Atlantic
Knutsen, Tor; Strand, Espen; Klevjer, Thor A.; Salvanes, Anne Gro Vea; Broms, Cecilie; Sunde, Synne Myhre; Aksnes, Dag Lorents; García-Seoane, Eva; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2023)The glacier lanternfish Benthosema glaciale is a key myctophid with a wide distribution in the northern Atlantic. It is a species that has a strong vertical migration capacity and have the potential to move between the ... -
Harp seal body condition and trophic interactions with prey in Norwegian high Arctic waters in early autumn
Haug, Tore; Biuw, Martin; Gjøsæter, Harald; Knutsen, Tor; Lindstrøm, Ulf; MacKanzie, Kirsteen M.; Meier, Sonnich; Nilssen, Kjell Tormod (Peer reviewed; Journal article, 2020)In September 2016, a marine ecosystem survey covered all trophic levels from phytoplankton to seals in the Arctic Ocean to the west and north of Svalbard. At the ice edge, 26 harp seals were sampled to assess whether recent ... -
High Latitude Epipelagic and mesopelagic scattering layers-a reference for future Arctic ecosystem change
Knutsen, Tor; Wiebe, Peter H.; Gjøsæter, Harald; Ingvaldsen, Randi Brunvær; Lien, Gunnar (Peer reviewed; Journal article, 2017) -
Micronekton biomass distribution, improved estimates across four north Atlantic basins
Klevjer, Thor A.; Melle, Webjørn Raunsgård; Knutsen, Tor; Strand, Espen; Korneliussen, Rolf; Dupont, Nicolas; Salvanes, Anne Gro Vea; Wiebe, Peter H. (Peer reviewed; Journal article, 2019)Distribution of micronekton was investigated during early summer of 2013, using data from a cruise covering the central parts of four north Atlantic basins, the Norwegian Sea (NS), Iceland Sea (ICS), Irminger Sea (IRS), ... -
Modeling the target strength of Calanus finmarchicus
Francis, David T. I.; Foote, Kenneth G.; Knutsen, Tor; Calise, Lucio (Others, 1999) -
Modeling the target strength of Meganyctiphanes norvegica
Francis, David T. I.; Knutsen, Tor; Foote, Kenneth G.; Calise, Lucio (Others, 1999) -
Schooling of the vertically migrating mesopelagic fish Maurolicus muelleri in light summer nights
Kaartvedt, Stein; Knutsen, Tor; Holst, Jens Christian (Journal article; Peer reviewed, 1998-09-03)Vertically migrating Maurolicus muelleri arrested their nocturnal ascent below the peak zooplankton concentrations during Light summer nights at 62 degrees N. At 69 degrees N, the behavior was further modified, with M, ... -
A seven-octave-bandwidth echo sounding system for application to fish and zooplankton
Foote, Kenneth G.; Knutsen, Tor; Atkins, Philip R.; Bongiovanni, Claire; Francis, David T. I.; Eriksen, Peter K.; Mortensen, Tom (Others, 1999) -
Simple, nonoptimal, real-time classifiers for euphausiid and copepod numerical density estimation
Atkins, Philip R.; Bongiovanni, Claire; Francis, David T. I.; Foote, Kenneth G.; Knutsen, Tor; Eriksen, Peter K.; Larsen, Mette Torp; Mortensen, Tom (Others, 2001) -
Spatial structuring in early life stage fish diversity in the Scotia Sea region of the Southern Ocean
Dornan, Tracey; Knutsen, Tor; Krafft, Bjørn Arne; Kvalsund, Merete; Mateos-Rivera, Alejandro; Tarling, Geraint A.; Wienerroither, Rupert; Hill, Simeon L. (Peer reviewed; Journal article, 2023)The fish community of the Scotia Sea is diverse and plays key roles in Antarctic food webs and biogeochemical cycling. However, knowledge of the spatial and community structure of their early life stages is limited, ...