Data/hora: 01/06/2024 18:50:55

Provedor de dados: | 5
País: | France
Título: | Evaluation of the performance and robustness of VPA-based stock assessment and MSY-based management strategy to process error: the Atlantic bluefin tuna case study
Autores: | Fromentin, Jean-marc; Kell, Laurence T.
Data: | 2009
Ano: | 2009
Palavras-chave: | Thunnus thynnus; Stock assessment; VPA; Biological reference points; MSY; Management strategy; Simulation model.
Resumo: | An integrative simulation framework was built to evaluate the consequences of variability attributable to changes in carrying capacity or the stock’s migration pattern of Atlantic bluefin tuna on the ICCAT stock assessment and management procedures. We also evaluated the performances of stock assessment methods with respect to their ability to provide good estimates of MSY, FMSY and BMSY and tested the robustness of the current ICCAT management strategy to uncertainty about the true dynamics and historical exploitation levels. The results clearly indicate that the VPA performances were seriously impaired if the long-term variations in catches are due to changes in migration/availability. There is further considerable confounding between the underlying dynamics and increasing effort that makes it difficult to draw any inference about the actual dynamics based on commercial catch data. Reference points based on F (e.g., F0.1) were less biased and more precise than those based on yield and/or SSB and were also more robust to uncertainty about the true dynamics than absolute values of F and SSB. However, F0.1 cannot indicate past and current levels of exploitation relative to FMSY when there is uncertainty about the dynamics. Therefore, while reference points such as F0.1 may be good proxies for FMSY, the MSY concept may be difficult to make operational. A size limit strategy generates greater yields than the more sophisticated F0.1, but lower SSB. However, the performances of both strategies were strongly dependent on the period over which they are implemented relative to the intrinsic cycle of the population. We finally stressed that the performances and robustness of management strategies also depend on concrete objectives, such as fleet composition, gear selectivity and economic constraints.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/00192/30295/28786.pdf

http://archimer.ifremer.fr/doc/00192/30295/

Editor: | ICCAT
Formato: | application/pdf
Fonte: | Collective Volume of Scientific Papers (1021-5212) (ICCAT), 2009 , Vol. 64 , N. 2 , P. 491-506

Fonte:

ICCAT

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