ICCAT MSE
This site hosts work on some of the MSE using R being conducted by the SCRS
MSE involves a number of steps
- Identification of management objectives and mapping these into utility functions or statistical indicators of performance;
- Selection of hypotheses for the operating models (OMs) that serve as the simulated version of reality;
- Conditioning of the OMs using data and knowledge, and weighting of possible model hypotheses depending on their plausibility;
- Identifying candidate management strategies and coding these as MPs;
- Projecting the OMs forward in time using the MPs as a feedback controller, simulating the impact of management \citep{ramaprasad1983definition}; and
- identifying the elements of MPs that best meet management objectives.
Operating Models
There are various ways of developing OMs and the amount of knowledge, data requirements and complexity differs quite markedly depending on the type to be used. Basing an operating model on the current assessment model has arguably the lowest demands for knowledge and data. Although use of the assessment model as the operating model seems to imply that assessment models describe nature almost perfectly, if an MP cannot perform well when reality is as simple as implied by an assessment model, it is unlikely to perform adequately for more realistic representations of uncertainty.
Therefore in the development of MSE within ICCAT the 1st stage is to take the existing assessments as the OMs
Applications
North Atlantic Albacore
ICCAT has asked the SCRS to evaluate a Harvest Control Rule (HCR) for North Atlantic albacore using Management Strategy Evaluation, see http://iccat-mse.github.io/albn-mse.html for a summary.
Work started on the MSE in 2013 when advice was provided in the form of a HCR with target and limit reference points. This HCR was then simulation tested using an Operating Model (OM) based on Multifan-CL.
The code used to conduct the MSE is available from a public github repository, and uses the FLR libraries written in R.
The stock is to be reassessed in 2016 and in light of this new assessment the Commission shall review the results of the MSE conducted so far and make adjustments to the HCRs as required (Rec-015-04).
An Operating Model has been developed based on Multifan-CL, there is already an implicit Management Procedure (MP) based on a biomass dynamic model and a hockey stick Harvest Control Rule. and the OM has been used to simulate test the MP