Browsing Publikasjoner fra CRIStin by Author "Ona, Egil"
Now showing items 1-15 of 15
-
Accuracy of the Kirchhoff-approximation and Kirchhoff-ray-mode fish swimbladder acoustic scattering models
Macaulay, Gavin; Pena, Hector; Fässler, Sacha M.M.; Pedersen, Geir; Ona, Egil (Journal article; Peer reviewed, 2013)The acoustic backscatter from pressure release prolate spheroids and a three-dimensional representation of a fish swimbladder (Chilean jack mackerel, Trachurus symmetricus murphyi) was calculated using four target strength ... -
Acoustic detection of the Greenland shark (Somniosus microcephalus) using multifrequency split beam echosounder in Svalbard waters
Ona, Egil; Nielsen, Julius (Peer reviewed; Journal article, 2022)The conservation status of the long-lived Greenland shark (Somniosus microcephalus) is unknown, and methods for non-invasively estimating local or regional abundances are wanted. Using a multifrequency split beam echosounder ... -
Antarctic krill (Euphausia superba) catch weight estimated with a trawl-mounted echosounder during fishing
Krafft, Bjørn Arne; Krag, Ludvig A.; Pedersen, Ronald; Ona, Egil; Macaulay, Gavin (Peer reviewed; Journal article, 2023)Reporting reliable catch weight estimates is important for all fisheries management. This study explores the potential for precise and direct estimation of catch weight (green weight) for the Antarctic krill (Euphausia ... -
Atlantic cod (Gadus morhua)feeding over deep water in the high Arctic
Ingvaldsen, Randi Brunvær; Gjøsæter, Harald; Ona, Egil; Michalsen, Kathrine (Peer reviewed; Journal article, 2017) -
Comparisons of echo-integration performance from two different multiplexed echosounders
Macaulay, Gavin; Schoulding, Ben; Ona, Egil; Fässler, Sascha M. M. (Journal article; Peer reviewed, 2018)A time-series of acoustically derived aquatic biomass estimates relies on the acoustic equipment maintaining the same performance throughout the time-series. This is normally achieved through a regular calibration process. ... -
CRIMAC - Annual Report 2020
Ona, Egil; Handegard, Nils Olav; Pedersen, Geir; Forland, Tonje Nesse; Tenningen, Maria; Johnsen, Espen (Research report, 2021) -
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 ... -
Feasibility study on the use of scientific multibeam sonar to characterize the Atlantic Bluefin Tuna spawning stock
Tenningen, Maria; Pena, Hector; Korneliussen, Rolf; Ona, Egil; Pons, Vicent Puig (Rapport fra havforskningen;2019 - 34, Research report, 2019)The Institute of Marine Research (IMR) and the Polytechnic University of Valencia (UPV) were invited by ICCAT Atlantic-Wide Research Program for Bluefin Tuna (GBYP) to carry out a feasibility study on the use of scientific ... -
In situ calibration of observatory broadband echosounders
Ona, Egil; Zhang, Guosong; Pedersen, Geir; Johnsen, Espen (Peer reviewed; Journal article, 2020)Today, numerous scientific echosounders are used as continuously monitoring systems in ocean observatories. These echosounders are usually calibrated in shallow water, either in laboratory tanks or at random ocean docks ... -
Kan måle fiskestørrelse før fangsting
Ona, Egil (Havforskningsnytt;Nr. 6-2016, Working paper, 2016) -
Mesopelagic fish gas bladder elongation, as estimated from wideband acoustic backscattering measurements
Khodabandeloo, Babak; Ona, Egil; Pedersen, Geir; Korneliussen, Rolf; Melle, Webjørn Raunsgård; Klevjer, Thor Aleksander (Peer reviewed; Journal article, 2022)Backscattered acoustic energy from a target varies with frequency and carries information about its material properties, size, shape, and orientation. Gas-bearing organisms are strong reflectors of acoustic energy at the ... -
Nonlinear crosstalk in broadband multi-channel echosounders
Khodabandeloo, Babak; Ona, Egil; Macaulay, Gavin; Korneliussen, Rolf (Peer reviewed; Journal article, 2021)Distortion of acoustic wave caused by nonlinear propagation transfers acoustic energy into higher harmonics of the transmitted signal. When operating several broadband echosounders with non-overlapping frequency bands to ... -
Quantitative processing of broadband data as implemented in a scientific split-beam echosounder
Andersen, Lars Nonboe; Chu, Dezhang; Handegard, Nils Olav; Heimvoll, Harald; Korneliussen, Rolf; Macaulay, Gavin; Ona, Egil; Patel, Ruben; Pedersen, Geir (Peer reviewed; Journal article, 2023)The use of quantitative broadband echosounders for biological studies and surveys can offer considerable advantages over narrowband echosounders. These include improved spectral-based target identification and significantly ... -
Remote sizing of fish-like targets using broadband acoustics
Kubilius, Rokas; Macaulay, Gavin; Ona, Egil (Peer reviewed; Journal article, 2020) -
Study of the Arctic mesopelagic layer with vessel and profiling multifrequency acoustics
Dias Bernardes, Inês; Ona, Egil; Gjøsæter, Harald (Peer reviewed; Journal article, 2020)