Blar i Brage IMR på forfatter "Øvredal, Jan Tore"

A new radio link telemetry positioning system, experiences from tracking of fish and crustaceans

Bjordal, Åsmund; Engås, Arill; Soldal, Aud Vold; Øvredal, Jan Tore (ICES CM Documents;1993/B:23, Working paper, 1993)

Telemetry positioning systems based on hydrophone arrays have been used for different tracking applications. The main improvement of this new system is the wire-less transmission of signals from hydrophone - radio buoys ...

A PC-based echo integrator system appliable for school structure analyzis

Floen, Svein; Totland, Bjørn; Øvredal, Jan Tore; Misund, Ole Arve (ICES CM Documents;1991/B:43, Working paper, 1991)

A low cost system for integration of echo signals on a PC has been developed. The system calculates the area backscattering strength in surface and bottom layers, and is designed both for the purpose of conventional ...

Acoustic measurements of schooling herring. Estimation of school biomass and target strength

Misund, Ole Arve; Øvredal, Jan Tore (ICES CM Documents;1988/B:26, Working paper, 1988)

The connections between reflected echo energy and dimensions of fatty herring schools were studied by a combination of multibeam sonar and a calibrated echo integration unit. A relation between the area and the biomass ...

Akustisk fangstovervåking i not – Utfordringer og løsningsforslag til bedre metodikk

Tenningen, Maria; Øvredal, Jan Tore; Macaulay, Gavin (Rapport fra havforskningen;42-2018, Research report, 2018)

Akustisk sensor for fangstkontroll i notfiske - Spesifikasjoner for montering og bruk

Tenningen, Maria; Schuster, Erik; Saltskår, Jostein; Øvredal, Jan Tore (Rapport fra havforskningen;2021 - 11, Research report, 2021)

Fangst- og redskapsovervåking gir kontroll over fangstprosessen og kan bidra til å redusere utilsiktet dødelighet og gi et mer målrettet og effektivt fiske. I prosjekt «Fangstkontroll i notfiske etter pelagiske arter» (FHF ...

Akustisk styring av motor for å åpne/lukke luke i styrbare tråldører og funksjonstester av nytt rullegear på semipelagisk rigget bunntrål om bord i M/S ”Fangst” i august 2014

Valdemarsen, John Willy; Øvredal, Jan Tore; Aasen, Asbjørn; Corneliussen, Jon Even; Bærhaugen, Thor; Nedrebø, Trond (Rapport fra Havforskningen;Nr. 26-2014, Working paper, 2014-10)

Automatic recording of fish heart rate on a personal computer

Floen, Svein; Totland, Bjørn; Øvredal, Jan Tore (ICES CM Documents;1988/B:34, Working paper, 1988)

From acoustic tags operated into fish in a closed system, the heartbeat signals are sent via underwater telemetry and counted on a personal computer. The computer removes false pulses caused by noise, and calculates the ...

Automatic species recognition, length measurement and weight determination, using the CatchMeter computer vision system

Svellingen, Cato; Totland, Bjørn; White, Darren; Øvredal, Jan Tore (ICES CM documents, Working paper, 2006)

The collection of biological data on species composition and individual length and weight of specimen has always been an important part of fisheries research. Traditionally, the collected information has been recorded on ...

Avoidance reactions of ultrasonic tagged cod during bottom trawling in shallow water

Engås, Arill; Soldal, Aud Vold; Øvredal, Jan Tore (ICES CM Documents;1991/B:41, Working paper, 1991)

Introduction: Observations made by echo sounder (Ona 1988) have shown that cod (Gadus morhua L.) may avoid an approaching survey vessel horizontally and vertically. However, there has been a lack of information on the ...

Behavioural and welfare implications of a new slipping methodology for purse seine fisheries in Norwegian waters

Anders, Neil; Breen, Michael; Saltskår, Jostein; Totland, Bjørn; Øvredal, Jan Tore; Vold, Aud (Journal article; Peer reviewed, 2019)

The release of unwanted fish from purse seines whilst still in the water is termed slipping and may lead to significant mortality following release. The objective of this study was to determine the fish welfare implications ...

Beste praksis for slipping fra not. Utvikling av standard slippemetode for makrell og sild i fiske med not

Vold, Aud; Anders, Neil; Breen, Mike; Saltskår, Jostein; Totland, Bjørn; Øvredal, Jan Tore (Rapport fra Havforskningen;6-2017, Working paper, 2017)

Ved en Workshop som ble avholdt på Gardermoen desember 2014 ble fiskere, forskere og forvaltning enige om et forslag til «Beste praksis for slipping fra not», dvs. et sett av retningslinjer som skulle beskrive en god ...

CRISP- Toktrapport. Testing trålutstyr og instrumentering. G. O. Sars 1.-11. mars 2015

Valdemarsen, John Willy; Øvredal, Jan Tore; Aasen, Asbjørn; Engås, Arill; Rosen, Shale; Macaulay, Gavin; Mæstad, Odd Kjartan; Sæstad, Arvid; Nedrebø, Trond; Bærhaugen, Thor; Vågstøl, Håvard; Knotten, Vidar (Rapport fra havforskningen;10-2016, Research report, 2016)

Effekter av seismiske undersøkelser på fiskefordeling og fangstrater for garn og line i Vesterålen sommeren 2009 : Effects of seismic surveys on fish distribution and catch rates of gillnets and longlines in Vesterålen in summer 2009

Løkkeborg, Svein; Ona, Egil; Vold, Aud; Peña, Hector; Salthaug, Are; Totland, Bjørn; Øvredal, Jan Tore; Dalen, John; Handegard, Nils Olav (Fisken og havet, Research report, 2010-02-22)

In connection with the Norwegian Petroleum Directorate’s seismic survey off the coasts of Vesterålen in summer 2009, a project was carried out to study the degree to which commercial fishes were affected. Four chartered ...

Elektronisk målebrett for lengdebestemmelse

Øvredal, Jan Tore (Havforskningsnytt, Working paper, 1996)

Er det mulig å standardisere metoder for slipping av pelagiske fiskearter i notfiske?

Isaksen, Bjørnar; Saltskår, Jostein; Vold, Aud; Totland, Bjørn; Øvredal, Jan Tore (Rapport fra Havforskningen;Nr. 5-2014, Working paper, 2014-02)

How and why acoustic detectability and catchability of herring change with individual motivation and physiological state in a variable environment: a multi-scale study on a local herring population in southwestern Norway

Langård, Lise; Nøttestad, Leif; Johannessen, Arne; Fernö, Anders; Øvredal, Jan Tore; Skaret, Georg; Nilsson, Gro N.; Vabø, Rune (ICES CM documents, Working paper, 2006)

The understanding of distribution and aggregation in herring (Clupea harengus) can be enhanced by integrated multi-scale studies in small ecosystems. Hydro-acoustics, underwater cameras, herring and predator gillnet samples ...