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Developing age determination criteria for Bocaccio (Sebastes paucispinus)
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2015
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[PDF-941.49 KB]
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Alternative Title:Age determination criteria for Bocaccio
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Description:Bocaccio (Sebastes paucispinus) are an important part of the commercial and recreational fisheries in California. Since 1983, this species has been repeatedly subjected to stock assessments. By the early 1990's, it was apparent that the species was in danger of being overfished, and regulatory measures were implemented to protect it. In spite of those efforts, the species was declared overfished in 2000, and catches in the fishery were heavily constrained. Age data were only marginally useful in early assessments because the species was deemed too difficult to age, and reliable criteria had not been developed. Since 1999, assessments have excluded age data due to inconsistencies with the length data. In this paper we describe how we finally developed age determination criteria for this species. The approach to development relied on using otoliths from Washington as well as a combination of other methods, based on fish length compositions and cross-sectioning of the otoliths, to obtain a better idea of how annuli were formed. After developing the criteria, a total of 850 otolith samples were double-read by two age readers. Age determination error analysis showed that there were generally good agreements between the two age readers. Estimated standard deviations of age determination errors increased for older fish, ranged from 0.270 for age 1 to 6.77 for age 36.
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Content Notes:Donald E. Pearson, Lyndsey S. Lefebvre, Xi, He.
"April 2015."
System requirements: Adobe Acrobat Reader.
Includes bibliographical references (pages 22-24).
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Rights Information:Public Domain
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