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dc.contributor.authorRøttingen, Ingolf
dc.contributor.authorFoote, Kenneth G.
dc.contributor.authorHuse, Ingvar
dc.contributor.authorOna, Egil
dc.date.accessioned2012-09-10T15:07:45Z
dc.date.available2012-09-10T15:07:45Z
dc.date.issued1994
dc.identifier.citationThis report is not to be cited without prior reference to the authorsno_NO
dc.identifier.urihttp://hdl.handle.net/11250/105253
dc.description.abstractThe spawning component and part of the juvenile stock of Norwegian spring spawning herring have been wintering in a fjord system in northern Norway in recent years. Conditions for measuring the stock size have been excellent. Here, results are presented from the December 1993 and January 1994 cruises with RIV "Johan Hjort", supplemented by measurements with RIV "Michael Sars" in December 1993. Following a review of the biology, principal elements of the survey are described, namely design, acoustic measurements, and biological sampling. A variety of auxiliary studies, some ongoing, are breifly reviewed. The subjects of these are ( 1) acoustic extinction, (2) fish orientation in situ, (3) fish target strength in situ, ( 4) geographic differences in size distribution and associated dynamics, ( 5) herring fat content, ( 6) hydrography with respect to herring distribution, (7) inter-ship calibration of echo integrators, and (8) multi-frequency echo integration. Methods of analysis: criteria for echogram interpretation, stratification, global averaging, and geostatistical estimation of variance, are described. Results of the acoustic survey are expressed through absolute numbers for abundance, composite size distribution, and estimates of confidence associated with the degree of coverage based on geostatistics. The results are placed in the context of other methods of assessment and prognoses. Error sources in the acoustic abundance estimate are enumerated and critiqued. Outstanding problems, if obvious, are mentioned.no_NO
dc.language.isoengno_NO
dc.publisherICESno_NO
dc.relation.ispartofseriesICES CM Documents;1994/(B+D+G+H):1
dc.subjectacousticsno_NO
dc.subjectakustikkno_NO
dc.subjectherringno_NO
dc.subjectsildno_NO
dc.subjectstock assessmentno_NO
dc.subjectbestandsberegningno_NO
dc.subjectsamplingno_NO
dc.subjectprøvetakingno_NO
dc.subjectdistributionno_NO
dc.subjectutbredelseno_NO
dc.titleAcoustic abundance estimation of wintering Norwegian spring spawning herring, with emphasis on methodological aspectsno_NO
dc.typeWorking paperno_NO
dc.subject.nsiVDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fisheries technology: 924no_NO
dc.subject.nsiVDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452no_NO
dc.subject.nsiVDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Resource biology: 921no_NO
dc.subject.nsiVDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923no_NO
dc.source.pagenumber36 s.no_NO


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