Terms of Reference

Evaluating Benchmarks of Biological Status for Data-limited Populations (Conservation Units) of Pacific Salmon, Focusing on Chum Salmon in Southern BC

Regional Peer Review Process – Pacific Region

July 12-13, 2017
Nanaimo, British Columbia

Chairperson: Bruce Patten

Context

The Pacific Salmon Treaty (PST) Chum Annex requires biological benchmarks to inform the use of the critical threshold level for chum salmon to Johnstone Strait (currently set at 1 million) in upcoming PST renegotiations of the Chum Annex. Reference points that are currently being used for management have not been recently updated and may not reflect current trends in productivity, stock statuses, or other ecosystem considerations. Advice on biological benchmarks, and their applications as fisheries reference points, will also inform assessments for Marine Steward Council (MSC) certification of chum salmon and future stock assessments for terminal fisheries of chum salmon.

Biological information is needed to inform domestic and international assessment and management (e.g. PST, Wild Salmon Policy, and Marine Stewardship Certification). At this time however, most conservation units of chum salmon in southern BC have significant data limitations. Biological benchmarks for data-limited populations have been proposed and are currently being applied to Conservation Units (CUs, population units of biological assessment under Canada’s Wild Salmon Policy) of chum salmon in southern BC. These methods which are based on percentiles of historical spawner abundances have not been rigorously evaluated against standard abundance-based benchmarks recommended under Canada’s Wild Salmon Policy for data-rich CUs.

DFO Science has requested that Science Branch provide advice on the use of biological benchmarks for southern BC chum salmon in light of acknowledged data limitations. Specifically, an evaluation of percentile-based benchmarks will include the biological, assessment, and management conditions where those benchmarks are higher (more precautionary) or lower (less precautionary) than standard abundance-based benchmarks derived previously under the Wild Salmon Policy (Holt et al. 2009; Holt 2009).

Objectives

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

• Holt, C., Davis, B, Dobson, D., Godbout, L., Luedke, W., Tadey, J., Van Will, P.  Evaluating Benchmarks of Biological Status for Data-limited Populations (Conservation Units) of Pacific Salmon, Focusing on Chum Salmon in Southern BC. CSAP Working Paper 2015SAL04

The specific objectives of this review are to:

1. Evaluate biological benchmarks for data-limited Conservation Units of Chum Salmon based on percentiles of observed abundances and compare to standard model-based benchmarks accounting for high uncertainties and possible biases in spawner abundances, catches, recruitment estimates, and age-at-maturity.
1. This evaluation will include simulation and retrospective analyses using data from Chum Salmon in southern BC, where available.
2. A sensitivity analysis of evaluations will be performed in simulation to identify the conditions under which benchmarks meet conservation objectives.
2. Examine and identify uncertainties in the data, methods, and benchmarks. Develop and demonstrate a tool to report uncertainties in the assessments.
3. Provide advice on the applicability of percentile-based benchmarks for data-limited populations of chum salmon in southern BC.

Expected Publications

• Proceedings
• Research Document

Participation

• Fisheries and Oceans Canada (DFO) (Ecosystems and Oceans Science and Ecosystems and Fisheries Management sectors)
• PST Chum Technical Committee members
• Academia
• First Nations
• Non-governmental organizations
• Commercial and recreational fishing interests

References

Holt, C., Cass, A., Holtby, B., and Riddell, B. 2009. Indicators of status and benchmarks for conservation units in Canada’s Wild Salmon Policy. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/058. viii + 74 p.

Holt, C.A. 2009. Evaluation of benchmarks for conservation units in Canada’s Wild Salmon Policy: Technical Documentation. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/059. x + 50 p.