dc.contributor.author | Hjellvik, Vidar | |
dc.contributor.author | Godø, Olav Rune | |
dc.contributor.author | Tjøstheim, Dag | |
dc.date.accessioned | 2012-11-21T16:10:07Z | |
dc.date.available | 2012-11-21T16:10:07Z | |
dc.date.issued | 2004 | |
dc.identifier.citation | This report is not to be cited without prior reference to the authors | no_NO |
dc.identifier.uri | http://hdl.handle.net/11250/106609 | |
dc.description.abstract | Introduction: In the Barents Sea, the echo abundance of demersal fish is about 50% higher at day than at night. Three possible reasons are:
• Fish hide in the bottom dead zone at night.
• Fish target strength changes due to pressure-related swim-bladder changes during vertical migration.
• Fish target strength varies due to higher variation in the tilt-angle distribution at night.
It is very often claimed that the dead zone is most important. We argue that variation in tilt-angle may also be important. | no_NO |
dc.language.iso | eng | no_NO |
dc.publisher | ICES | no_NO |
dc.relation.ispartofseries | ICES CM Documents;2004/R:33 | |
dc.subject | acoustics | no_NO |
dc.subject | akustikk | no_NO |
dc.subject | stock assessment | no_NO |
dc.subject | bestandsberegning | no_NO |
dc.title | Diurnal variation in acoustic densities: why do we se less in the dark? | no_NO |
dc.type | Working paper | no_NO |
dc.subject.nsi | VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fisheries technology: 924 | no_NO |
dc.source.pagenumber | 1 s. | no_NO |