Terms of Reference

Continuation of 4VWX Herring Framework Part II: Operating Model Development

Regional Peer Review – Maritimes Region

May 26-27, 2020
Virtual meeting

Chairperson: Tara McIntyre

Context

Atlantic herring is a pelagic species found on both sides of the North Atlantic. Herring spawn in discrete locations, to which they are presumed to home. Herring first mature and spawn at three or four years of age (23 to 28 cm), then begin a predictable annual pattern of spawning, overwintering, and summer feeding, which often involves considerable migration and mixing with members of other spawning groups. The NAFO areas 4VWX management unit contains a number of spawning areas. Spawning areas in close proximity with similar spawning times, and which share a larval distribution area, are considered part of the same complex. For evaluation and management, the 4VWX herring fisheries are divided into four components:

1. Southwest Nova Scotia/Bay of Fundy (SWNS/BoF) spawning component
2. Offshore Scotian Shelf banks spawning component
3. Coastal (South Shore, Eastern Shore and Cape Breton) Nova Scotia spawning component
4. Southwest New Brunswick migrant juveniles.

Recommendations from the last assessment framework conducted in 2011 included a focus on model improvement and exploration for the next framework (DFO 2011). This assessment framework will focus on the SWNS/BoF spawning component. The last stock assessment for this component was conducted in 2018 (DFO 2018), and a stock status update was provided in 2019 (DFO 2019). The 2018 assessment identified the framework assessment as a priority and in 2019 the SWNS/BoF spawning component was identified to be in the critical zone.

Fisheries and Oceans Canada (DFO), Maritimes Region is proceeding with a management strategy evaluation (MSE) process as the framework for SWNS/BoF Herring. This meeting is the third of four Science Advisory Process meetings to develop this MSE, and will involve the final peer-review of the conditioning operating model to be used in the MSE. The first meeting was in February 2019 and addressed the data inputs. The second meeting was in January 2020 and was a review of the structure and fitting of an example operating model that will be used as the basis for all of the operating models in the MSE. The fourth meeting, to be scheduled later in the year, will involve the review of the entire MSE process.

Objectives

The objective of this third meeting is to review the structure and fitting of the operating models that will be used as the basis for all of the operating models in the MSE. The operating models span the range of uncertainties identified for the fishery in the workshop held in January 2020. This meeting will involve a review of:

• updates to the data inputs;
• final scenarios and parameter estimates used to capture uncertainty in the operating models;
• goodness of fit of the operating models and suitability to be used to model a range of uncertainties for the fishery;
• prior assumptions and error structure in the operating model.

The review of the conditioning operating model differs from the review of a standard assessment model. The focus of the review of a standard assessment model is on model goodness of fit, whereas the focus of this review is on the suitability of the operating model to be used to model a range of uncertainties for the fishery. The code (R/Template Model Builder) will be available for reviewers so anything documented in the working paper can be replicated.

Expected Publications

• Proceedings
• Research Document

Expected Participation

• DFO Science
• DFO Resource Management
• DFO Ecosystem Management
• DFO Policy
• Members of the Herring Advisory Committee
• University of British Columbia modelling team

References

DFO. 2011. Proceedings of the Maritimes Region Science Advisory Process on the Assessment Framework for Southwest Nova Scotia/Bay of Fundy Herring; 24-28 January 2011. DFO Can. Sci. Advis. Sec. Proceed. Ser. 2011/031: iv + 28p.

DFO. 2018. Assessment of 4VWX Herring. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2018/052.

DFO. 2020. Stock Status Update of 4VWX Herring for the 2018/2019 Fishing Season. DFO Can. Sci. Advis. Sec. Sci. Resp. 2020/001.