Terms of Reference

Shortspine Thornyhead (Sebastolobus alascanus) Stock Assessment for the Pacific Coast of Canada in 2015

Regional Peer Review Process – Pacific Region

December 10-11 and 18, 2015
Nanaimo, British Columbia

Chair: Maria Surry

Context

Shortspine Thornyhead (Sebastolobus alascanus) has increasingly been caught by the commercial trawl fishery since the mid-1980s. A coastwide total allowable catch (TAC) limit was first set in 1997 (748 t) and is currently 771 t. Although there is some directed fishing effort on this species, it is largely caught along with other groundfish species in the commercial trawl fishery. Minor catch amounts are taken by the hook and line fisheries. The geographic range of Shortspine Thornyhead is extensive (Love et al. 2002), occurring from the Sea of Japan, through the Aleutian Islands and down along the west coast of North America to Baja California. The depth range for this species varies widely (down to 1500 m) but it is found most often in commercial catches between 150 and 450 m depth, with spawning aggregations in the oxygen minimum zone (600-1000 m) (Jacobson and Vetter 1996). Shortspine Thornyhead larvae and juveniles spend 12-14 months in the pelagic zone before settling onto the shelf at 100 m depth. As this species gets older and larger, it migrates into deeper water. This is may be an adaptation to reduce the risk of predation. The most recent stock assessment to review this species occurred in 1999 (Schnute et al. 1999).  A quantitative population model has not previously been used to assess this species. Fisheries and Oceans Canada (DFO) Fisheries Management has requested that the Shortspine Thornyhead coastwide stock be assessed relative to reference points that are consistent with the DFO Precautionary Approach (DFO 2009), and that probabilistic decision tables be produced that forecast the impacts of varying harvest levels on stock status.

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 following working paper to provide the basis for discussion and advice on the specific objectives outline below:

Paul J. Starr and Rowan Haigh. Shortspine Thornyhead (Sebastolobus alascanus) Stock Assessment for the Pacific Coast of Canada in 2015. CSAS Working Paper 2014GRF04

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

• Review and evaluate stock and fishery monitoring data available for assessment of stock status and harvest projections of Sebastolobus alascanus.
• Test the ability of the available data to support quantitative assessment model determinations of stock status.
• Suggest candidate reference points (either biomass-based or fishing mortality-based) consistent with the DFO Precautionary Approach, including alternatives to models-based reference points.
• If possible, provide forecasts of the predicted status of Shortspine Thornyhead Rockfish relative to candidate reference points across a range of management actions.

If possible, provide science advice appropriate for management of Shortspine Thornyhead at smaller spatial scales; or, provide rationale why this is not possible.

Expected Publications

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

Participation

• DFO (Science, Fisheries Management, Oceans, Habitat)
• Aboriginal communities
• Province of British Columbia
• External reviewers
• Industry
• Non-governmental organizations and other scientists and stakeholders.

References

DFO. 2009. A fishery decision-making framework incorporating the Precautionary Approach.

Jacobson, L.D., and Vetter, R.D. 1996. Bathymetric demography and niche separation of thornyhead rockfish: Sebastolobus alascanus and Sebastolobus altivelis. Can. J. Fish. Aq. Sci. 53: 600-609.

Love, M.S., Yoklavich, M., and Thorsteinson, L. 2002. The Rockfishes of the Northeast Pacific. University of California Press, Berkley CA. 404 p.

Schnute, J.T., Olsen, N., and Haigh, R. 1999. Slope rockfish assessment for the west coast of Canada in 1998. DFO Can. Sci. Advis. Sec. Res. Doc. 1999/184. vi +104 p.