Terms of Reference

The Selection and Role of Limit Reference Points for Pacific Herring (Clupea pallasii) in British Columbia, Canada

Regional Peer Review Process – Pacific Region

February 7-8, 2017
Nanaimo, British Columbia

Chairperson: Linnea Flostrand

Context

Pacific Herring (Clupea pallasii) in British Columbia (BC) has a long heritage of quantitative stock assessment and management that incorporates comprehensive data collection for stock and fishery monitoring, statistical catch-at-age assessment models, and a harvest control rule (DFO 2015).  Stock assessment analysts and fisheries managers have worked closely together to address the challenges posed by the fisheries which are of interest to a diverse array of resource users.  In these regards, the current management framework for Pacific Herring already has many of the required elements of the Fishery Decision-making Framework Incorporating the Precautionary Approach policy (DFO 2009).  Elements yet to be developed include the selection of both limit and target reference points, and an evaluation process to allow the consequences of management choices to be examined in a way that makes trade-offs between conservation, yield and social outcomes explicit.

Limit reference points (LRPs) indicate states that should not be breached (a lower biomass or abundance limit) or exceeded (a fishing mortality limit) due to anticipated undesirable consequences or “serious harm” to the stock such as impaired productivity, genetic restrictions, or stock collapse.  Methods appropriate for determining LRPs are not well understood for Pacific Herring fisheries, particularly given the apparent time-varying biological processes related to productivity such as changing natural mortality and weight-at-age.  Cox et al. (2015^{Footnote 1}) considered equilibrium limit reference points that remain fixed over time, a dynamic reference point that tracks changes in productivity, a “historical” reference point that defined an LRP in terms of lowest observed biomass, and DFO (2009) policy values of 0.4BMSY and FMSY.  Advice that resulted from Cox et al. (2015^{Footnote 1}) and international best practices consistent with Canadian policy will be considered when recommending LRPs for Pacific Herring in this review.

Under the current approach for assessment and management of Pacific Herring (“operational stream”), a single model and harvest control rule are used to provide catch recommendations.  However, the long-term focus of Science activities related to revising the Pacific Herring management framework is the establishment of a Management Strategy Evaluation (MSE) process to identify a management procedure (i.e., data collection, assessment method, and harvest control rule) that has been simulation tested for robustness to a range of uncertainties regarding stock and fishery dynamics.  Therefore, the role of LRPs in the context of the current operational stream and the evolving “strategic stream” guided by the MSE process will be discussed.  Strengths and weaknesses of the recommended LRPs will be described relevant to the context in which they would be used.

This Canadian Science Advisory Secretariat (CSAS), Regional Peer Review (RPR) will focus on the concept of serious harm in identifying LRPs for Pacific Herring and evaluate the evidence for identifying states when serious harm might occur.  The rationale for recommended status-based and fishing mortality limit reference points for the five major stocks of Pacific Herring will be reviewed.  Advice arising from this CSAS RPR will be used to establish LRPs for Pacific Herring in Canada and inform the renewal of the management framework in accordance with Canada’s Sustainable Fisheries Framework.

Objectives

The following working paper will be reviewed and provide the basis for discussion and advice on the objectives outlined below:

• Kronlund, A.R., Forrest, R.E., Cleary, J.S., and Grinnell, M.H. 2017. The Selection and Role of Limit Reference Points for Pacific Herring (Clupea pallasii) in British Columbia, Canada. CSAS Working Paper 2016PEL01.

The objectives of this review are to:

1. Determine whether existing data and assessment model estimates provide evidence for states of “serious harm” or “slowly reversible harm” for Pacific Herring stocks and if so, how these states align with LRPs.
2. Evaluate whether biological reference points derived from estimates of key management parameters are appropriate choices for LRPs in light of evidence for time-varying processes (e.g., estimated time trends in natural mortality and observed trends in weight-at-age for Pacific Herring).
3. Determine if the ecosystem role of Pacific Herring as a forage fish should influence or modify the choice of LRPs.
4. Recommend LRPs for Pacific Herring consistent with the DFO Sustainable Fisheries Framework.
5. Recommend next steps required to develop measurable objectives that include LRPs and subsequently evaluate the effects of LRP choices in the context of the entire management system.

Expected Publications

• CSAS Science Advisory Report
• CSAS Research Document
• CSAS Proceedings

Expected Participation

• DFO (Science, Fisheries Management)
• External reviewers
• First Nations
• Fishing Industry
• Academia

References

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

DFO. 2015. Stock Assessment and Management Advice for BC Pacific Herring: 2015 Status and 2016 Forecast. DFO Can. Sci. Advis. Sec. Sci. Resp. 2015/038.