dc.contributor.author | Toresen, Reidar | |
dc.date.accessioned | 2012-08-21T14:28:36Z | |
dc.date.available | 2012-08-21T14:28:36Z | |
dc.date.issued | 1990 | |
dc.identifier.citation | This report is not to be cited without prior reference to the author | no_NO |
dc.identifier.uri | http://hdl.handle.net/11250/104687 | |
dc.description.abstract | The absorption of acoustic energy in herring schools is studied by echo integration of the
bottom signal under various densities of herring. The investigations were carried out in a
fjord in northern Norway, where large schools of adult herring overwinter. The intensity
of the bottom signal, expressed by the integrator value (reflected area in square meters per
square nautical mile(m^2/NM^2
)) of the bottom decreased significantly as the density of
herring increased. The bottom integrator value decreased exponentially from 1.39 to 0.36
· 10^6 as the area density of herring increased from 0 to 550 · 10^3 corresponding to an
increase in number of herring per square meter of 0 - 180. A method for correction of this
effect is also presented. | no_NO |
dc.language.iso | eng | no_NO |
dc.publisher | ICES | no_NO |
dc.relation.ispartofseries | ICES CM Documents;1990/B:2 | |
dc.subject | acoustics | no_NO |
dc.subject | akustikk | no_NO |
dc.subject | herring | no_NO |
dc.subject | sild | no_NO |
dc.title | Absorption of acoustic energy in dense herring schools studied by the attenuation in the bottom echo signal | 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.subject.nsi | VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452 | no_NO |
dc.source.pagenumber | 16 s. | no_NO |