Terms of Reference

Evaluating the robustness of management procedures for the Sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada for 2017-18

Regional Peer Review – Pacific Region

January 10-11, 2017
Nanaimo, British Columbia

Chairperson: John Holmes

Context

Fisheries and Oceans Canada (DFO) and the British Columbia (BC) Sablefish fishing industry collaborate on a management strategy evaluation (MSE) process intended to develop and implement a transparent and sustainable harvest strategy.  Sustainability of harvest strategies is determined by simulation testing alternative management procedures against operating models that represent a range of hypotheses about uncertain Sablefish stock and fishery dynamics.  Performance of management procedures used in these tests is measured against pre-agreed conservation and catch objectives for the stock and fishery (Cox et al. 2011, DFO 2014).

A revised Sablefish operating model was developed in January 2016 (DFO 2016) that implements a two-sex/age-structured model to account for differences in growth, mortality, and maturation of male and female Sablefish, adjusted model age-proportions via an ageing error matrix, and revised the multivariate-logistic age composition likelihood to reduce model sensitivity to small age proportions.  Structural revisions to the operating model provide a better fit to age-composition and at-sea release data that were not well-fit by the previous operating model.  Accounting for ageing errors improved the time-series estimates of age-1 Sablefish recruitment by reducing the unrealistic auto-correlation present in the previous model results.

Sablefish begin to appear in commercial fisheries at 2-3 years of age, but are required to be released by regulation when measuring less than 55 cm fork length.  The improved recruitment estimates derived from the operating model help to explain the temporal pattern of at-sea releases.  As a consequence, it may be possible to improve the evaluation of potential impacts of these at-sea releases on exploitable Sablefish biomass and productivity by Cox et al. (2011).  If post-release estimates are determined to be more significant than previously determined, management procedures such as full retention, avoidance, or catch limits on sub-legal Sablefish by one or more gear types may be required to reduce post-release mortality effects that compromise performance of the Sablefish management system.

Fisheries Management has requested advice from Science to inform planning for the 2017-18 fishing year that incorporates the improvements to the Sablefish operating model and tests the existing and alternative management procedures for robustness to uncertain stock and fishery dynamics.  It is expected that advice will be compliant with both the “DFO Sustainable Fisheries Framework” (SFF) policy and “A fishery decision-making framework incorporating the Precautionary Approach” (PA) policy.

Objectives

Guided by the DFO Sustainable Fisheries Framework, particularly the Fishery Decision-making Framework Incorporating the Precautionary Approach (DFO 2009), meeting participants will review the working paper:

• Evaluating the robustness of management procedures for the Sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada for 2017-18. Cox, S.P., Kronlund, A.R., and Lacko, L.  CSAS Working Paper 2014GRF08.

The working paper will be used to provide advice with respect to the following objectives:

1. Provide the results of fitting (conditioning) a range of operating model configurations that represent hypotheses about uncertain Sablefish dynamics to updated stock monitoring and fishery data.
2. Characterise Sablefish stock status relative to outcomes specified in conservation and fishery objectives for each of the operating model configurations.
3. Quantify and rank the relative performance of candidate management procedures against the objectives.  Procedures may include:
   1. the original procedure implemented in 2011 (Cox et al. 2011);
   2. the current procedure that incorporates a catch floor (DFO 2014);
   3. a new procedure that adds a catch ceiling to the current procedure; and
   4. modifications of (a-c) that implement full retention, avoidance, and/or sub-legal catch limits.
4. Evaluate whether mortality attributable to at-sea releases across all fishery sectors compromises the achievement of fishery objectives related to conservation and growth of the stock.

Expected Publications

• Science Advisory Report
• Research Document
• Proceedings

Participation

• Fisheries and Oceans Canada (DFO) (Science, Fisheries Management sectors)
• Academics
• Aboriginal communities/organizations
• Industry (groundfish commercial fishing industry)

References Cited

Cox, S.P., Kronlund, A.R., Lacko, L. 2011. Management procedures for the multi-gear Sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2011/063. viii + 45 p.

DFO. 2009. A Fishery Decision-making Framework Incorporating the Precautionary Approach.

DFO. 2014. Performance of a revised management procedure for Sablefish in British Columbia. DFO Can. Sci. Advis. Sec. Sci. Resp. 2014/025.

DFO. 2016. A revised operating model for Sablefish (Anoplopoma fimbria) in British Columbia, Canada. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/015.