Size-at-age and condition of cod in subdivision 3Ps as determined from bottom-trawl surveys (1972-1997) / by G.R. Lilly. : Fs70-1/1998-94E-PDF
Cod (Gadus morhua) in several areas of Atlantic Canada experienced pronounced declines in growth and condition during the late 1980s and early 1990s. The degree to which such changes occured in the stock off the south coast of Newfoundland (Subdivision 3Ps) is difficult to assess because the DFO bottom-trawl surveys have varied considerably in timing and there appear to be strong year effects in size-at-age data that have not yet been explained. The major purpose of this paper is to explore in more detail the size at age and condition data available from cod sampled during the surveys in 1972-1996 and to update the analyses with data collected in 1997. A second purpose is to document the method used to calculate the January 1 weights-at-age used during the 1998 assessment of 3Ps cod. The relative merits of commercial data and research vessel data are discussed, and the reasons for continuing to use commercial weights-at-age at this time are described.
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| Ministère/Organisme | Canada. Department of Fisheries and Oceans. Canada. Canadian Stock Assessment Secretariat. |
|---|---|
| Titre | Size-at-age and condition of cod in subdivision 3Ps as determined from bottom-trawl surveys (1972-1997) / by G.R. Lilly. |
| Titre de la série | Canadian Stock Assessment Secretariat research document, 1480-4883 ; 98/94 |
| Type de publication | Série - Voir l'enregistrement principal |
| Langue | [Anglais] |
| Format | Électronique |
| Document électronique | |
| Note(s) | Includes bibliographical references (p. 9-10). |
| Information sur la publication | Ottawa : Fisheries and Oceans Canada, 1998. |
| Auteur / Contributeur | Lilly, G. R.,1945- |
| Description | 29 p. : fig., graphs, tables. |
| Numéro de catalogue |
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| Descripteurs | Fisheries resources Salt water fish Fishing area Fisheries management |
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