Terms of Reference
Review of a Simulation Testing Method for Evaluation of Potential Management Strategies for Northern Cod (Divs. 2J3KL)
Regional Science Response Process – Newfoundland and Labrador Region
June 27-28, 2016
St. John’s, NL
Chairperson: Peter Shelton
Context
During the December 2015 Northern Cod Framework Review, Fisheries and Oceans Canada’s (DFO) Science Branch accepted a new quantitative method (NCAM; Cadigan 2016) for assessing the status of the stock. This state-space model is a highly complex representation of population dynamics, integrating various input data sources to provide estimates of stock size.
Fisheries Managers and Industry Stakeholders participating in the informal DFO cod recovery working group have expressed interest in risk-based evaluation of multiple potential Harvest Control Rules (HCRs). Given its complexity, simulation testing of HCR using the NCAM as either the assessment model or as the basis for the operating model would be an extensive research project.
An external consultant to the fishing industry has developed a closed-loop computer simulation framework for evaluating proposed future harvest strategies for Divs. 2J3KL cod. The framework includes an age-structured operating model that mimics past dynamics of the stock as estimated by NCAM (Cadigan 2016, DFO 2016) and several long-term projection scenarios into the future based on different assumptions regarding recruitment, natural mortality, growth, selectivity, etc. Management strategies are evaluated by applying a harvest control to stock estimates obtained with error from a simulated statistical catch at age assessment applied to the historic and the projected period.
Although a HCR will be applied to illustrate future population dynamics, the Regional Science Response Process will not evaluate any candidate HCR or consider performance statistics related to management objectives.
Objectives
- Determine whether the closed-loop computer simulation framework has an operating model that provides a reasonable approximation of the 2016 assessment results generated from NCAM.
- Determine whether the statistical catch at age assessment model applied in the simulations can provide a representative estimate (over the assessment time-period) of the operating model from a dataset generated from the operating model with process and observation errors.
- Determine whether the projection scenarios are plausible and representative of the range of possibilities.
It is recognized that additional issues may arise during the Regional Science Response Process related to this analysis that need to be considered that are not identified above.
Expected Publications
- Science Response
- Research Document
Expected Participation
- Fisheries and Oceans Canada (DFO) (Science and Fisheries Management Branches)
- Department of Fisheries and Aquaculture, Government of Newfoundland and Labrador
- Industry scientists
References
Cadigan, N. 2016. Updates to a Northern Cod (Gadus morhua) State-Space Integrated Assessment Model. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/022. v + 58 p.
DFO. 2016. Stock Assessment of Northern Cod (NAFO Divs. 2J3KL) in 2016. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/026.
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