A meta-analytic approach to quantifying scientific uncertainty in stock assessments

Ralston, Stephen and Punt, André E. and Hamel, Owen S. and DeVore, John D. and Conser, Ramon J. (2011) A meta-analytic approach to quantifying scientific uncertainty in stock assessments. Fishery Bulletin, 109(2), pp. 217-231.

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Quantifying scientific uncertainty when setting total allowable catch limits for fish stocks is a major challenge, but it is a requirement in the United States since changes to national fisheries legislation. Multiple sources of error are readily identifiable, including estimation error, model specification error, forecast error, and errors associated with the definition and estimation of reference points. Our focus here, however, is to quantify the influence of estimation error and model specification error on assessment outcomes. These are fundamental sources of uncertainty in developing scientific advice concerning appropriate catch levels and although a study of these two factors may not be inclusive, it is feasible with available information. For data-rich stock assessments conducted on the U.S. west coast we report approximate coefficients of variation in terminal biomass estimates from assessments based on inversion of the assessment of the model’s Hessian matrix (i.e., the asymptotic standard error). To summarize variation “among” stock assessments, as a proxy for model specification error, we characterize variation among multiple historical assessments of the same stock. Results indicate that for 17 groundfish and coastal pelagic species, the mean coefficient of variation of terminal biomass is 18%. In contrast, the coefficient of variation ascribable to model specification error (i.e., pooled among-assessment variation) is 37%. We show that if a precautionary probability of overfishing equal to 0.40 is adopted by managers, and only model specification error is considered, a 9% reduction in the overfishing catch level is indicated.

Item Type: Article
Title: A meta-analytic approach to quantifying scientific uncertainty in stock assessments
Personal Creator/Author:
Ralston, Stephen
Punt, André E.
Hamel, Owen S.
DeVore, John D.
Conser, Ramon J.
Refereed: Yes
Journal or Publication Title: Fishery Bulletin
Volume: 109
Number: 2
Page Range: pp. 217-231
Date: 2011
ISSN: 0090-0656
Issuing Agency: United States National Marine Fisheries Service
Subjects: Biology
Item ID: 8718
Depositing User: Patti M. Marraro
Date Deposited: 07 Jun 2012 14:54
Last Modified: 07 Jun 2012 14:54
URI: http://aquaticcommons.org/id/eprint/8718

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