Terms of Reference

Pacific Herring Assessment Framework; Stock Assessment and Management Advice (2011 Status and 2012 Forecast)

Pacific Regional Science Advisory Process

September 7-9, 2011
Pacific Biological Station, Nanaimo, BC

Chairperson: Linnea Flostrand

Context

Annually, an assessment of Pacific herring abundance and forecasts for the coming year is generated for each of the five major and two minor stocks in British Columbia, using a statistical catch–age-model. The assessment framework integrates data from sampling the population with analytical methods to model population dynamics and harvest control rule components. The annual assessment is reviewed through a Canadian Science Advisory Secretariat Regional Advisory Process (RAP) and harvest advice is provided to Fisheries and Oceans Canada (DFO) Fisheries Management each fall to inform the development of the Integrated Fisheries Management Plan (IFMP).

Refinements to the herring statistical catch-age model have occurred on an ongoing basis since its earliest version (Haist and Stocker 1984), with the last major review in 2008 (Christensen et al 2009) and with some updates in 2009 and 2010 (Cleary et al 2009, DFO 2009a, DFO 2010). However, recent RAP reviews have identified specific aspects of the current model’s structural assumptions and decision rules that warrant a more in depth review (DFO 2009a).  In addition to the formal RAP reviews, the Herring Conservation and Research Society (HCRS) sponsored a herring stock assessment model review in June of 2010, which also produced recommendations to explore a number of data issues and alternative structural assumptions in the model.

In order to be more compliant with DFO’s Sustainable Fisheries Framework (SFF) policy “A fishery decision-making framework incorporating the Precautionary Approach” (DFO 2009b), the Herring Assessment Team, led by DFO Science, has developed an alternative modeling framework to address some of the recommendations that have come forth at RAP reviews concerning model assumptions and decision rules. This RAP will review changes to the statistical catch-age model and compare model outputs with the outputs from the previous version of the statistical catch-age model.   This RAP will also review 2011 biomass estimates and forecasts for the 2011/2012 fishing season.

One research document (structured in two parts) will be presented and reviewed.  The meeting will also be structured as two Parts: (1) formal review of revised stock assessment model and framework, and (2) provision of science advice for the 2011/12 fishing season.

Objectives

Working paper to be reviewed: 

Moving towards the sustainable fisheries framework for Pacific herring: data, models, and alternative assumptions; and Stock Assessment and Management Advice for the British Columbia Herring Stocks: 2011 Assessment and 2012 Forecasts – CSAP Working Paper 2011-P56/P06.  Steven Martell, Jake Schweigert, Jaclyn Cleary and Vivian Haist

Part 1: Moving towards the sustainable fisheries framework for Pacific herring: data, models, and alternative assumptions

Specific technical components of the Pacific herring statistical catch-age population assessment model assumptions and structure to be evaluated include: 

• Model structure and parameterization,
• Confounding effects of natural mortality (M) and spawn survey catchability (q),
• Gear selectivity, catchability, recruitment, and productivity estimation,
• Model priors, likelihoods, and decision rules, and
• Estimation of unfished biomass and stock depletion levels (time series of annual biomass over unfished biomass).

Part 2: Stock Assessment and Management Advice for the British Columbia Herring Stocks: 2011 Assessment and 2012 Forecasts

• What is the estimated 2011 spawning biomass for Pacific Herring by major and minor stock assessment area?
• How are herring stocks in these areas changing over time?
• What is the forecasted spawning biomass for 2012? 
• Are there any specific concerns that Fisheries Management should be aware of, and if so, what are those concerns?

Expected publications

• CSAS Proceedings (1)
• CSAS Science Advisory Report (1)
• CSAS Research Document (1)

Participation

DFO Science Branch
DFO Fisheries Management Branch
Province of B.C.
Commercial and recreational fishing interests
First Nations organizations
Non-government organizations
Academia

References Cited and Additional Information

Christensen, L.B., V. Haist and J. Schweigert. Modeling herring population dynamics. Herring catch-at-age model version 2. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/073. 65p.   http://www.dfo-mpo.gc.ca/csas-sccs/publications/resdocs-docrech/2009/2009_073-eng.htm

Cleary, J.S., Schweigert, J.F., Haist, V.  Stock assessment and management advice for the British Columbia herring fishery: 2009 assessment and 2010 forecasts. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/079. vii + 81 p.
http://www.dfo-mpo.gc.ca/csas-sccs/publications/resdocs-docrech/2009/2009_079-eng.htm

DFO. 2009a. Proceedings of the Pacific Scientific Advice Review Committee (PSARC) Pelagic Subcommittee Meeting: Stock assessment and management advice for BC herring fishery, 2009 assessment and 2010 forecasts and herring multi-stock analysis; September 2, 2009. DFO Can. Sci. Advis. Sec. Proceed. Ser. 2009/037.
http://www.dfo-mpo.gc.ca/csas-sccs/Publications/Pro-Cr/2009/2009_037-eng.htm

DFO. 2009b. A fishery decision-making framework incorporating the Precautionary Approach. http://www.dfo-mpo.gc.ca/reports-rapports/regs/sff-cpd/precaution-back-fiche-eng.htm

DFO 2011. Stock Assessment Report on Pacific Herring in British Columbia in 2010. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/064.

Haist, V., and M. Stocker. 1984. Stock assessment for British Columbia herring in 1983 and forecasts of the potential catch in 1984. Can. MS Rep. Fish. Aquat. Sci. 1751: 50p.