The Management Strategy Evaluation Approach and the Fishery for Walleye Pollock in the Gulf of Alaska

Author(s):  
Z. Teresa Amar ◽  
Andre Punt ◽  
Martin Dorn
2021 ◽  
Author(s):  
Margaret C. Siple ◽  
Laura E. Koehn ◽  
Kelli F. Johnson ◽  
André E. Punt ◽  
T. Mariella Canales ◽  
...  

2013 ◽  
Vol 26 (4) ◽  
pp. 365-379 ◽  
Author(s):  
Dorleta Garcia ◽  
Agurtzane Urtizberea ◽  
Guzman Diez ◽  
Juan Gil ◽  
Paul Marchal

2019 ◽  
Vol 76 (9) ◽  
pp. 1653-1668 ◽  
Author(s):  
T.R. Carruthers ◽  
A.R. Hordyk

A new indicator is described that uses multivariate posterior predictive data arising from management strategy evaluation (MSE) to detect operating model misspecification (exceptional circumstances) due to changing system dynamics. The statistical power of the indicator was calculated for five case studies for which fishery stock assessments have estimated changes in recruitment, natural mortality rate, growth, fishing efficiency, and size selectivity. The importance of the component data types that inform the indicator was also calculated. The indicator was tested for multiple types of management procedures (e.g., catch limits by stock assessment, size limits, spatial closures) given varying qualities of data. The statistical power of the indicator could be high even over short time periods and depended on the type of system change and quality of data. Statistical power depended strongly on the type of management approach, suggesting that indicators should be established that rigorously account for feedbacks between proposed management and observed data. MSE processes should use alternative operating models to evaluate protocols for exceptional circumstances to ensure they are of acceptable statistical power.


2019 ◽  
Vol 217 ◽  
pp. 198-216 ◽  
Author(s):  
M.A. Haltuch ◽  
E.N Brooks ◽  
J. Brodziak ◽  
J.A. Devine ◽  
K.F. Johnson ◽  
...  

2019 ◽  
Vol 76 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Robert B Thorpe ◽  
José A A De Oliveira

Abstract Maximum sustainable yield (MSY) is a well-established concept that is mandated by legislation, and has a clear theoretical meaning in terms of a single stock. However, its definition is problematic in a multispecies setting, which makes it more difficult to apply the MSY principle. In this study of the North Sea fish community, we consider several possible MSY candidates, and evaluate them in terms of their ability to produce optimum long-term yield whilst avoiding unacceptable risk of stock impairment. We perform this evaluation with an ensemble of size-structured models using a management strategy evaluation approach, in which harvest control rules (HCRs) are used to determine levels of fishing as a function of the proposed MSY target and stock status, taking account of recruitment and model parameter uncertainties. We find that HCRs of the type considered here are always useful in the scenarios we tested, as they reduce overfishing risk much more than average long-term yield. This is independent of the precise form of the HCR, so it is more important to implement one rigorously than obsess over the rule details. For a lax definition of overfishing, which accepts relatively severe stock depletion (B < 10% B0), and using HCRs, risks are “low” across all strategies, and the Nash equilibrium is the best performing MSY approach considered here. For more stringent definitions of “at risk” (e.g. likelihood of B < 20% of B0), the application of HCRs can allow a range of alternative formulations of MSY. Thus, the definition of MSY may be sensitive to judgements about acceptable levels of risk, and consistent application of a sensible management framework may be more important than developing the best possible theoretical definition of MSY.


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