Blar i Brage IMR på forfatter "Agersted, Mette Dalgaard"
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Acoustic micronektonic distribution and density is structured by macroscale oceanographic processes across 17–48° N latitudes in the North Atlantic Ocean
García-Seoane, Eva; Klevjer, Thor A.; Mork, Kjell Arne; Agersted, Mette Dalgaard; Macaulay, Gavin; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2023)This study investigates the large-scale distribution patterns of the acoustic scattering layers and micronekton density across the Northeast Atlantic Ocean during daylight hours. A research cruise on board R/V “Kronprins ... -
Application of an unsupervised clustering algorithm on in situ broadband acoustic data to identify different mesopelagic target types
Agersted, Mette Dalgaard; Khodabandeloo, Babak; Liu, Yi; Melle, Webjørn Raunsgård; Klevjer, Thor Aleksander (Peer reviewed; Journal article, 2021)The mesopelagic zone (200–1000 m depth) contains high fish species diversity but biomass and abundances are uncertain yet essential to understand ecosystem functioning. Hull-mounted acoustic systems (usually 38 kHz) often ... -
Calanus finmarchicus basin scale life history traits and role in community carbon turnover during spring
Jónasdóttir, Sigrún H; Naustvoll, Lars Johan; Teglhus, Frederik Wolff; Agersted, Mette Dalgaard; Grenwald, Julie C; Melle, Webjørn Raunsgård; Nielsen, Torkel Gissel (Peer reviewed; Journal article, 2022)The copepod Calanus finmarchicus was investigated in four Subpolar Basins, Labrador, Irminger, Iceland, and Norwegian Seas, during spring, covering the time of ascent, grazing, and initiation of reproduction in the area. ... -
A comparison of CTD satellite-linked tags for large cetaceans - Bowhead whales as real-time autonomous sampling platforms
Teilmann, Jonas; Agersted, Mette Dalgaard; Heide-Jørgensen, Mads-Peter (Peer reviewed; Journal article, 2020)There is an increasing need for comprehensive oceanographic sampling, and taking advantage of marine mammal studies of movements and habitat use for augmenting spatial and temporal coverage, especially in remote and ... -
Effects of airgun discharges used in seismic surveys on development and mortality in nauplii of the copepod Acartia tonsa
Vereide, Emilie Hernes; Mihaljevic, Marina; Browman, Howard; Fields, David M.; Agersted, Mette Dalgaard; Titelman, Josefin; Jong, Karen de (Peer reviewed; Journal article, 2023)Seismic surveys are conducted worldwide to explore for oil and gas deposits and to map subsea formations. The airguns used in these surveys emit low-frequency sound waves. Studies on zooplankton responses to airguns report ... -
Effects of airgun discharges used in seismic surveys on development and mortality in nauplii of the copepod Acartia tonsa
Vereide, Emilie Hernes; Mihaljevic, Marina; Browman, Howard; Fields, David M.; Agersted, Mette Dalgaard; Titelman, Josefin; Jong, Karen de (Peer reviewed; Journal article, 2023)Seismic surveys are conducted worldwide to explore for oil and gas deposits and to map subsea formations. The airguns used in these surveys emit low-frequency sound waves. Studies on zooplankton responses to airguns report ... -
Estimating target strength and physical characteristics of gas-bearing mesopelagic fish from wideband in situ echoes using a viscous-elastic scattering model
Khodabandeloo, Babak; Agersted, Mette Dalgaard; Klevjer, Thor Aleksander; Macaulay, Gavin John; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2021)Wideband (38 and 50–260 kHz) target strength of organisms were measured in situ using a towed platform in mesopelagic (200–1000 m depth) layers. Organisms with a gas-inclusion are strong scatterers of sound and acoustically ... -
Mass estimates of individual gas-bearing mesopelagic fish from in situ wideband acoustic measurements ground-truthed by biological net sampling
Agersted, Mette Dalgaard; Khodabandeloo, Babak; Klevjer, Thor A.; García-Seoane, Eva; Strand, Espen; Underwood, Melanie; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2021)A new acoustic approach to estimate the mass of individual gas-bearing fish at their resident depth at more than 400 m was tested on Cyclothone spp.. Cyclothone are small and slender, and possibly numerically underestimated ... -
Mesopelagic flesh shear viscosity estimation from in situ broadband backscattering measurements by a viscous–elastic model inversion
Khodabandeloo, Babak; Agersted, Mette Dalgaard; Klevjer, Thor A.; Pedersen, Geir; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2021)In fisheries acoustics, target strength (TS) is a key parameter in converting acoustic measurements to biological information such as biomass. Modelling is a versatile tool to estimate TS of marine organisms. For swimbladdered ... -
Resource partitioning may limit interspecific competition among Arctic fish species during early life
Bouchard, Caroline; Chawarski, Julek; Geoffroy, Maxime; Klasmeier, Apasiri; Møller, Eva Friis; Mohn, Christian; Agersted, Mette Dalgaard (Peer reviewed; Journal article, 2022)Arctic cod (Boreogadus saida) strongly dominates the ichthyoplankton assemblages of High Arctic seas, hence competition with other native species seldom has been studied. Yet, interspecific competition could negatively ...