• Herding mesopelagic fish by light 

      Kaartvedt, Stein; Røstad, Anders; Opdal, Anders Frugård; Aksnes, Dag Lorents (Peer reviewed; Journal article, 2019)
      To assess organisms forming mesopelagic scattering layers in the Red Sea, we took advantage of their reactions to light. We used a remotely operated vehicle (ROV) equipped with LED lamps for herding the acoustic targets ...
    • Heterogeneous distribution of plankton within the mixed layer and its implications for bloom formation in tropical seas 

      Calbet, Albert; Agersted, Mette Dalgaard; Kaartvedt, Stein; Møhl, Malene; Møller, Eva Friis; Enghoff-Poulsen, Søren; Paulsen, Maria Lund; Solberg, Ingrid; Tang, Kam W.; Tönnesson, Kajsa; Raitsos, Dionysios E.; Nielsen, Torkel Gissel (Peer reviewed; Journal article, 2015-06-11)
      Intensive sampling at the coastal waters of the central Red Sea during a period of thermal stratification, prior to the main seasonal bloom during winter, showed that vertical patches of prokaryotes and microplankton ...
    • Impact of hatch-date on early life growth and survival of Mueller's pearlside (Maurolicus Muelleri) larvae, and life-history consequences 

      Folkvord, Arild; Gundersen, Geir; Albretsen, Jon; Asplin, Lars; Kaartvedt, Stein; Giske, Jarl (Peer reviewed; Journal article, 2016-02)
      Growth and survival of Maurolicus muelleri larvae in Herdlefjorden, Norway, were investigated by daily otolith increment analysis. While high egg densities were generally observed throughout the spawning season, three ...
    • Jellyfish distribute vertically according to irradiance 

      Bozman, Andrea; Titelman, Josefin; Kaartvedt, Stein; Eiane, Ketil; Aksnes, Dag Lorents (Peer reviewed; Journal article, 2017-03)
      We tested the hypothesis that the coronate jellyfish Periphylla periphylla distributes vertically according to a preferential range of absolute light intensities. The study was carried out in Lurefjorden, Norway, a fjord ...
    • Large mesopelagic fishes biomass and trophic efficiency in the open ocean 

      Irigoien, Xabier; Klevjer, Thor A.; Røstad, Anders; Martinez, U.; Boyra, G.; Acuna, J. L.; Bode, A.; Echevarria, F.; Gonzalez-Gordillo, J. I.; Hernández-León, Santiago; Augsti, S.; Aksnes, Dag Lorents; Duarte, C. M.; Kaartvedt, Stein (Peer reviewed; Journal article, 2014-02-07)
      With a current estimate of ~1,000 million tons, mesopelagic fishes likely dominate the world total fishes biomass. However, recent acoustic observations show that mesopelagic fishes biomass could be significantly larger ...
    • Light comfort zone in a mesopelagic fish emerges from adaptive behaviour along a latitudinal gradient 

      Langbehn, Tom; Aksnes, Dag Lorents; Kaartvedt, Stein; Fiksen, Øyvind; Jørgensen, Christian (Peer reviewed; Journal article, 2019)
      Throughout the oceans, small fish and other micronekton migrate between daytime depths of several hundred meters and near-surface waters at night. These diel vertical migrations of mesopelagic organisms structure pelagic ...
    • Light comfort zones of mesopelagic acoustic scattering layers in two contrasting optical environments 

      Røstad, Anders; Kaartvedt, Stein; Aksnes, Dag Lorents (Peer reviewed; Journal article, 2016-07)
      We make a comparison of the mesopelagic sound scattering layers (SLs) in two contrasting optical environments; the clear Red Sea and in murkier coastal waters of Norway (Masfjorden). The depth distributions of the SL in ...
    • Light penetration structures the deep acoustic scattering layers in the global ocean 

      Aksnes, Dag Lorents; Røstad, Anders; Kaartvedt, Stein; Martinez, Udane; Duarte, Carlos M.; Irigoien, Xabier (Peer reviewed; Journal article, 2017)
      The deep scattering layer (DSL) is a ubiquitous acoustic signature found across all oceans and arguably the dominant feature structuring the pelagic open ocean ecosystem. It is formed by mesopelagic fishes and pelagic ...
    • Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides 

      Busserolles de, Fanny; Cortesi, Fabio; Helvik, Jon Vidar; Davies, Wayne I. L.; Templin, Rachel M.; Sullivan, Robert K. P.; Michell, Craig T.; Mountford, Jessica K.; Collin, Shaun P.; Irigoien, Xabier; Kaartvedt, Stein; Marshall, Justin (Peer reviewed; Journal article, 2017)
      Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light ...
    • Vertical distribution and trophic interactions of zooplankton and fish in Masfjorden, Norway 

      Giske, Jarl; Aksnes, Dag Lorents; Balino, Beatriz M.; Kaartvedt, Stein; Lie, Ulf; Nordeide, Jarle Tryti; Salvanes, Anne Gro Vea; Wakili, Sami M.; Aadnesen, Agnes (Peer reviewed; Journal article, 1990)
      The distribution, biomass, and predator-prey relationships of the pelagic assemblage in Masfjorden, western Norway, was studied in January 1989. The pelagic biomass was dominated by particulate organic matter. Biomasses ...