Terms of Reference

Southwest Nova Scotia/Bay of Fundy Herring Framework: Part 2 – Management Strategy Evaluation Conditioning Operating Model Review

Regional Peer Review – Maritimes Region

January 21-22, 2020

Dartmouth, Nova Scotia

Meeting Chairs: Tara McIntyre and Darek Moreau

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:

• Southwest Nova Scotia/Bay of Fundy spawning component
• Offshore Scotian Shelf banks spawning component
• Coastal (South Shore, Eastern Shore and Cape Breton) Nova Scotia spawning component
• 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 Southwest Nova Scotia/Bay of Fundy (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 has decided to proceed with a management strategy evaluation (MSE) process as the framework for SWNS/BoF Herring. This meeting is the second of three Science Advisory Process meetings to develop this MSE, and will involve a 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 third meeting, to be scheduled later in the year, will involve the review of the entire MSE process.

Objectives

The objective of this second meeting is to review 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. This will involve a review of:

• the rationale for the data inputs;
• the rationale for the selected modelling approach;
• model specifications (i.e., equations for population dynamics, statistical functions, and numerical procedures);
• parameter estimates used in the operating model;
• suitability of the operating model 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

Participation

• DFO Science
• DFO Resource Management
• DFO Ecosystem Management
• DFO Policy
• Industry
• Contracted external experts

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

DFO. 2019. Stock Status Update of 4VWX Herring. DFO Can. Sci. Advis. Sec. Sci. Resp. 2019/0XX.