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  • ICES CM documents authored by IMR scientists (1949-2011)
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Acoustic assessment of Norwegian spring spawning herring in the wintering area, December 1995 and January 1995

Foote, Kenneth G.; Røttingen, Ingolf
Working paper
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CM_1995_H_9.pdf (2.029Mb)
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http://hdl.handle.net/11250/105435
Issue date
1995
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  • ICES CM documents authored by IMR scientists (1949-2011) [3135]
Original version
This report is not to be cited without prior reference to the authors  
Abstract
The abundance of the mature component of the stock of Norwegian spring

spawning herring has been estimated based on a series of echo integration

surveys. These were performed in the wintering area of Ofotfjord, Tysfjord,

and Vestfjord in December 1994 and January 1995 using the SIMRAD EK500/38 kHz

echo sounder and Bergen Echo Integrator postprocessing system. Compensation

has been made for extinction, assuming that the ratio of extinction and

backscattering cross sections is 2.41. Three considerations have dictated the

form of stratification of the wintering area: coastline compexity, presence of

herring, and herring size distribution as determined by pelagic trawling. The

variogram has been computed for each stratum to determine the characteristic

scale size of aggregation. Geostatistical theory has been applied to estimate

the variance associated with abundance estimates due to the degree of survey

coverage in relation to observed aggregation properties and fjord geometry.
Publisher
ICES
Series
ICES CM Documents;1995/H:9

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