Norwegian acoustic survey of North East Arctic cod on the spawning grounds off Lofoten

An acoustic survey of the spawning stock of North East Arctic Cod off Lofoten has been performed annually in March-April since 1982. The estimates for 1985-1997 have been recalculated and mean length and weight at age are shown together with the abundance indices (both numbers and biomass). The abun...

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Bibliographic Details
Main Author: Korsbrekke, Knut
Format: Report
Language:English
Published: ICES 1997
Subjects:
arctic cod
arktisk torsk
spawning areas
gyteplasser
acoustics
akustikk
stock assessment
bestandsberegning
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Catch: 925
VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923
Arctic
Lofoten
Arctic cod
Arktis*
Online Access:http://hdl.handle.net/11250/105785
Description
Summary:An acoustic survey of the spawning stock of North East Arctic Cod off Lofoten has been performed annually in March-April since 1982. The estimates for 1985-1997 have been recalculated and mean length and weight at age are shown together with the abundance indices (both numbers and biomass). The abundance indices for each age are compared with VPA results from a reasonably converged part of the series. It is shown that the VPA tuning assumption of constant log catchability at age should not be used for this survey series. As the survey produces abundance indices for the mature part of the cod stock these indices should be corrected with proportions mature before they are used in traditional assessment methods estimating year class strength.

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