Publication Abstract
- Title
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The precision of international market sampling for North Sea cod (Gadhus morhua L.) and its influence on stock assessment
- Publication Abstract
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The precision of international market sampling for North Sea cod (Gadhus morhua L.) and its influence on stock assessment
C.M. O'Brien, C.D. Darby, B.D. Rackham, D.L. Maxwell, H. Degel, S. Flatman, M. Mathewson, M.A. Pastoors, E.J. Simmonds and M. Vinther
Market sampling is an essential source of data for age-based finfish stock assessment. Previously, little has been documented about the influence of potential error in these data on the precision of stock assessments and the management information they produce. This paper presents the results of a EU-funded study (CFP Study Project 98/075) of the precision of North Sea cod (Gadus morhua L.) fish market sampling carried out by the United Kingdom (England & Wales, Scotland), Denmark, and the Netherlands. Data from eight years of market sampling conducted for the period 1991–1998 were analysed to obtain the precision of estimated numbers-at-age in the landed catch. The annual market sample data were then used to generate 1000 realisations of the international numbers-at-age and mean weights-at-age in the landed catch for the eight-year period selected. Matrices of the catch numbers-at-age were computed for the generated realisations, and these were used to produce 1000 stock assessments conditional on the XSA (Extended Survivors Analysis) model as implemented in 1999 at the ICES Working Group on the Assessment of Demersal Stocks in the North Sea. From the outcome of these assessments the influence of the market sampling programmes on the management of the stock are graphically presented as simulation envelopes on the main management parameters.
Reference:
C.M. O'Brien, C.D. Darby, B.D. Rackham, D.L. Maxwell, H. Degel, S. Flatman, M. Mathewson, M.A. Pastoors, E.J. Simmonds and M. Vinther, 2001. The precision of international market sampling for North Sea cod (Gadhus morhua L.) and its influence on stock assessment. ICES CM 2001/P:14. 29pp.
- Publication Internet Address of the Data
- Publication Authors
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C.M. O'Brien*, C.D. Darby*, B.D. Rackham*, D.L. Maxwell*, H. Degel, S. Flatman*, M. Mathewson, M.A. Pastoors, E.J. Simmonds and M. Vinther
- Publication Date
- January 2001
- Publication Reference
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ICES CM2001/P:14: 29pp
- Publication DOI: https://doi.org/
