Terms of Reference

Coastwide Assessment of Arrowtooth Flounder (Atheresthes stomias) in 2014 and recommendations for 2015

Regional Peer Review – Pacific Region

May 12-13, 2015
Nanaimo, British Columbia

Chairperson: Rowan Haigh

Context

Arrowtooth Flounder (Atheresthes stomias) is a significant species within the groundfish trawl fishery.  Since 2006 the fishery has been subject to a coastwide trawl Total Allowable Catch of 15 000 mt.  Arrowtooth Flounder are also a minor component of the groundfish hook and line fisheries and where vessels are subject to trip limits. The combined hook and line fisheries catch in 2013 was estimated to be 73 mt.  Arrowtooth Flounder is the second most frequently discarded species in the Pacific Halibut (Hippoglossus stenolepis) hook and line fishery (est. 12 mt) and consequently was identified as a component of the non-target catch in the Marine Stewardship Council certification process for the Pacific Halibut fishery.  The last assessment of Arrowtooth Flounder was published in 2001 (Fargo & Starr 2001) and provided analyses of biological, survey, commercial catch and catch-per-unit effort data. A formal, model-based assessment has never been done for this stock.

Updated stock status and harvest advice would assist in determining whether current harvest levels are sustainable and compliant with the Sustainable Fisheries Framework (SFF). One policy under the SFF, A Fishery Decision-making Framework Incorporating the Precautionary Approach (PA Framework) (DFO 2009), outlines the methods for applying the Precautionary Approach (PA) in the management of Canadian fisheries. Application of the PA usually implies estimation of fishery reference points and evaluation of current stock status relative to those reference points. Estimation of these quantities requires development of quantitative models, conditioned on available fishery, survey and biological data.

Landings and discard data for the Arrowtooth Flounder trawl fishery are unreliable prior to 1996.  Since 1996, 100% observer coverage in the commercial groundfish trawl fishery has provided reliable reporting of catch and discards.  Prior to 1996, however, landings of Arrowtooth Flounder were characterized by high proportions of discards due to low market demand, low value and the known rapid deterioration of product due to the presence of the same parasites prevalent in Pacific Hake. In many cases, the entire Arrowtooth Flounder catch in a trawl would be discarded, and in many cases Arrowtooth Flounder discards were not properly recorded in fishing logbooks. As a result of this inconsistent record keeping, trends in catch statistics prior to 1996 are biased and it will be impossible to reconstruct historical catches prior to 1996.  A model-based approach to the assessment of stock status, conditioned on estimates of historical catches before 1996, is therefore unlikely to be successful and has been dropped as a possible approach to the stock assessment of this species.  An alternative approach, which initializes the model from a non-equilibrium starting point and which is based on the reliable catch and discard time series beginning in 1996, may be possible.  However, such models are often difficult to resolve, due to the need to estimate additional parameters that may not be supported by the available data. Consequentially, attempts at a model-based stock assessment may fail.

The Fisheries Management Branch of Fisheries and Oceans Canada requested advice on (a) the status of Arrowtooth Flounder coastwide and (b) harvests consistent with DFO 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 following working paper to provide the basis for discussion and advice on the specific objectives outlined below. 

Grandin, C., and Forrest, R. Assessment of Arrowtooth Flounder (Atheresthes stomias) in 2014 and recommendations for management in 2015. CSAP Working Paper 2013GRF001

• Investigate the feasibility of conducting a model-based stock assessment.
• If model-based assessment is possible:
• Estimate reference points consistent with the DFO Precautionary Approach. Include the biological considerations and rationale used to make such a determination.
• Evaluate the current status of Arrowtooth Flounder relative to the estimated reference points.
• Evaluate the consequences of varying constant catches on future population status, providing decision tables and figures of long-term projected biomass.
•  If model-based assessment is not possible:
• Provide reasons why it is not possible.
• Present analyses of biological and fishery data.
• Investigate and provide alternative advice to managers, based on available data.
• Recommend research options to move toward a model-based assessment.
• Recommend an interval for re-assessment of Arrowtooth Flounder.

Expected Publications

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

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.

Fargo, J and Starr, P.J. 2001. Turbot stock assessment for 2001 and recommendations for management in 2002. Can. Stock Assess. Sec. Res. Doc. 2001/150. 70 p.