Blar i Brage IMR på forfatter "Ona, Egil"
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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) -
Fish reaction to trawling noise: The significance for trawl sampling
Ona, Egil; Godø, Olav Rune (Conference object, 1990)The reactions of fish during trawling were observed with a stationary echo sounder as a trawling vessel passed close to the transducer. Several strong, downward avoidance reactions of haddock (Melanogrammus aeglefinus ) ... -
Fjordranching with conditioned cod
Midling, Kjell; Kristiansen, Tore S.; Ona, Egil; Øiestad, Victor (ICES CM Documents;1987/F:29, Working paper, 1987)In June 1986, 1600 pond-reared one-year old cod were released into a fjord after being conditioned with a pulsed 160 Hz sound signal to search for food at a feeding location. Echosounders, UW-video and ultrasonic ... -
Fremtidsmetodar: Teknologi og fiskeriforskning
Ona, Egil; Godø, Olav Rune (Havforskningstema, Working paper, 2004) -
Haddock avoidance reactions during trawling
Ona, Egil; Chruickshank, O. (ICES CM Documents;1986/B:36, Working paper, 1986)Fish reaction to the whole trawling operation was studied using a stationary echo sounder-system observing the fish in front of the vessel and during trawl passage. Strong avoidance reactions were observed on haddock, ... -
Herring tilt angles, measured through target tracking
Ona, Egil (Report / Alaska Sea Grant College Program, Chapter, 2001)The target strength of herring in captivity was monitored experimentally at three frequencies (18, 38, and 120 kHz) over a period of 3 years using split-beam echo sounders. One of the fundamental parameters of a target ... -
High-resolution target strength measurements in deep water
Ona, Egil; Svellingen, Ingvald (Others, 1999) -
How many trawl hauls, and how many fish from each haul are needed to obtain a given precision in the age structure estimate for Norwegian spring spawning herring? A bootstrap approach
Hjellvik, Vidar; Ona, Egil (ICES CM documents, Working paper, 2006)The Norwegian spring spawning herring is assessed each year from acoustic surveys. The age structure in the stock is estimated from trawl samples. Typically, about 10 trawl samples are taken per survey, and 100 fish from ... -
Hull mounted, protruding transducer for improving echo integration in bad weather
Ona, Egil; Traynor, Jimmie J. (ICES CM documents, Working paper, 1990)A 38 kHz split beam survey transducer has been mounted on the tip of a 4 m vertical protrusile stabilizing keel of the United States NOAA fishery research vessel R/V Miller Freeman. Air blocking problems, generally ... -
Hull mounted, protruding transducer for improving echo integration in bad weather
Ona, Egil; Traynor, Jimmie J. (ICES CM Documents;1990/B:31, Working paper, 1990)A 38 kHz split beam survey transducer has been mounted on the tip of a 4 m vertical protrusile stabilizing keel of the United States NOAA fishery research vessel R/V Miller Freeman. Air blocking problems, generally ... -
Hydroacoustic performance of fishery survey instruments
Knudsen, Hans Petter; Ona, Egil; Svellingen, Ingvald (Others, 2001) -
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 ... -
In situ determination of bottom trawl ground gear contact
Engås, Arill; Ona, Egil; Ramberg, Kjell (ICES CM documents, Working paper, 2001)Exact definition of towed distance with proper ground gear contact is an essential parameter in bottom trawl swept area estimates of fish abundance. Errors in this key parameter may lead to a first order bias in abundance ... -
In situ observations of swimbladder compression in herring
Ona, Egil (ICES CM documents, Working paper, 1984)The hydrostatic function of the swimbladder in herring is experimentally investigated through in situ diver-assisted measurements of swimbladder volume on net-caught and caged fish. In agreement with morpho-physiological ... -
In situ target strength observations on haddock
Ona, Egil; Hansen, Kaare A. (ICES CM Documents;1986/B:39, Working paper, 1986)In situ target strength measurements of ideally resolved haddock have been made using the ES-400 split-beam echo sounder. The measurements are compared with the mean target strength obtained simultaneously by counting ... -
International acoustic herring survey: Norwegian sea [28/4 - 2/6, 1999]
Holst, Jens Christian; Ona, Egil ([Toktrapport/Havforskningsinstituttet];, Working paper, 1999) -
Kan måle fiskestørrelse før fangsting
Ona, Egil (Havforskningsnytt;Nr. 6-2016, Working paper, 2016) -
Lateral-aspect target strength measurements of in situ herring (Clupea harengus)
Pedersen, Geir; Handegard, Nils Olav; Ona, Egil (Journal article; Peer reviewed, 2009-07)Surveys of schooling herring with the new multi-beam sonar (Simrad MS70) pose new challenges when converting the echo energy to estimates of biomass. Since the sonar projects horizontally, data and models of lateral-aspect ... -
Lateral-aspect target strength measurements of in situ herring (Clupea harengus)
Pedersen, Geir; Handegard, Nils Olav; Ona, Egil (Journal article; Peer reviewed, 2009-07)Surveys of schooling herring with the new multi-beam sonar (Simrad MS70) pose new challenges when converting the echo energy to estimates of biomass. Since the sonar projects horizontally, data and models of lateral-aspect ... -
Måling av fiskestørrelse i stim med bredbånds ekkolodd
Ona, Egil (Havforskningsnytt;Nr. 6 - 2014, Working paper, 2014)