On the implication of tagging analyses for the shape of selectivity at age for Gulf of Maine Cod

 

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dc.contributor.author Butterworth, Doug S
dc.contributor.author Rademeyer, Rebecca A
dc.date.accessioned 2016-04-26T09:12:42Z
dc.date.available 2016-04-26T09:12:42Z
dc.date.issued 2008
dc.identifier.citation Butterworth, D. S., & Rademeyer, R. A. (2008). On the Implications of Tagging Analyses for the Shape of Selectivity at Age for Gulf of Maine Cod. US North East Fisheries Science Centre GARM WP4, 8, 1-5. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/19203
dc.description.abstract This paper provides some comments in response to Hart and Miller’s (2008) interpretation of the implications of their analyses of tagging data regarding the dome shape estimated for selectivity for Gulf of Maine cod in the ASPM Reference Case assessment of Butterworth and Rademeyer (2008a). It is first informative to consider the sensitivity of the 2007 Reference Case ASPM assessment of Butterworth and Rademeyer (2008a) to alternative values of age-independent natural mortality M. The results are shown in Table 1 and Fig. 1 below. From Fig. 1 it is clear that the inference or otherwise of a dome in selectivity depends strongly on the value assumed for M. If M=0.2 yr-1 as assumed for the Butterworth and Rademeyer (2008a) Reference Case, then selectivity for the NEFSC surveys is appreciably dome shaped with a rapid decline with age above age 7. However for M ~ 0.4 – 0.5, the selectivity for these ages becomes effectively flat. Interestingly, the tagging analyses of Hart and Miller (2008), from which they infer such flat selectivity, estimate (approximately) M=0.5 for length60 cm. en_ZA
dc.language eng en_ZA
dc.subject.other tagging analyses
dc.subject.other Gulf of Maine Cod
dc.title On the implication of tagging analyses for the shape of selectivity at age for Gulf of Maine Cod en_ZA
dc.type Working Paper en_ZA
dc.date.updated 2016-04-26T09:09:06Z
uct.type.publication Research en_ZA
uct.type.resource Research paper en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Resource Assessment and Management Group en_ZA
uct.type.filetype Text


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