Agenda Item D.8 Attachment 8 June 2015
Status of the U.S. sablefish resource in 2015 Kelli F. Johnson1,2 , Merrill B. Rudd1 , Maite Pons1 , Caitlin Allen1 , Qi Lee1 , Felipe Hurtado-Ferro1 , Melissa A. Haltuch3 , and Owen S. Hamel3 May 21, 2015 1 University of Washington School of Aquatic and Fishery Sciences 1122 NE Boat Street Seattle WA, 98105 2
[email protected]
3 National Marine Fisheries Service Northwest Fisheries Science Center 2725 Montlake Blvd. E. Seattle WA, 98122 206-860-3481 (phone) 206-860-3217 (fax)
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Contents Executive summary Stock . . . . . . . . . . . . . . Catches . . . . . . . . . . . . . Data and assessment . . . . . . Stock biomass . . . . . . . . . . Recruitment . . . . . . . . . . . Reference points . . . . . . . . Exploitation status . . . . . . . Management performance . . . Unresolved problems and major Forecasts . . . . . . . . . . . . Decision table . . . . . . . . . . Research and data needs . . . .
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1 Introduction 1.1 Distribution and stock structure . . . . . 1.2 Life history and ecosystem considerations 1.3 Historical and current fishery . . . . . . . 1.4 Management history and performance . . 1.5 Fisheries in Canada and Alaska . . . . . .
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2 Assessment 2.1 Fishery-Independent data . . . . . . . . . . . . . . 2.1.1 NWFSC Shelf-Slope bottom trawl survey . 2.1.2 NWFSC Slope bottom trawl survey . . . . 2.1.3 AFSC Slope bottom trawl survey . . . . . . 2.1.4 AFSC Triennial Shelf bottom trawl survey 2.1.5 Other fishery-independent data . . . . . . . 2.1.6 Environmental indices . . . . . . . . . . . . 2.2 Biological data . . . . . . . . . . . . . . . . . . . . 2.2.1 Weight-length relationship . . . . . . . . . . 2.2.2 Maturity schedule . . . . . . . . . . . . . . 2.2.3 Fecundity . . . . . . . . . . . . . . . . . . . 2.2.4 Natural mortality . . . . . . . . . . . . . . . 2.2.5 Ageing bias and imprecision . . . . . . . . . 2.3 Fishery-Dependent data . . . . . . . . . . . . . . . 2.3.1 Historical commercial landings . . . . . . . 2.3.2 Foreign catches . . . . . . . . . . . . . . . . 2.3.3 Fishery catch-per-unit-effort . . . . . . . . . 2.3.4 Fishery biological data . . . . . . . . . . . . 2.3.5 Discard ratio estimates . . . . . . . . . . . 2.3.6 Discard mortality estimates . . . . . . . . . 2.4 History of modeling approaches . . . . . . . . . . . 2.4.1 Previous assessments . . . . . . . . . . . . .
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2.4.2 Response to STAR Panel recommendations in 2011 . Model description . . . . . . . . . . . . . . . . . . . . . . . . 2.5.1 Link from the 2011 to the 2015 assessment model . . 2.5.2 Summary of fleets . . . . . . . . . . . . . . . . . . . 2.5.3 Modeling software . . . . . . . . . . . . . . . . . . . 2.5.4 Priors . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5.5 Sample weighting . . . . . . . . . . . . . . . . . . . . 2.5.6 General model specifications . . . . . . . . . . . . . 2.5.7 Estimated and fixed parameters . . . . . . . . . . . Model selection and evaluation . . . . . . . . . . . . . . . . 2.6.1 Key assumptions and structural choices . . . . . . . 2.6.2 Convergence status . . . . . . . . . . . . . . . . . . . Response to SSC recommendations . . . . . . . . . . . . . . Base-Case model results . . . . . . . . . . . . . . . . . . . . Uncertainty and sensitivity analysis . . . . . . . . . . . . . . 2.9.1 Sensitivity analysis . . . . . . . . . . . . . . . . . . . 2.9.2 Retrospective analysis . . . . . . . . . . . . . . . . . 2.9.3 Parametric bootstrap using Stock Synthesis . . . . .
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3 Reference points
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4 Harvest projections and decision tables
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5 Regional management considerations
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6 Research needs
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7 Acknowledgements
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8 References
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9 Tables
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10 Figures
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Executive summary Stock This assessment update reports the status of the sablefish (Anoplopoma fimbria, or ‘black cod’) resource off the coast of the United States (U.S.) from southern California to the U.S.-Canadian border using data through 2014. The resource is modeled as a single stock, however sablefish do disperse to some degree to and from offshore seamounts and along the coastal waters of the continental U.S., Canada, Alaska, and across the Aleutian Islands to the western Pacific and this is not explicitly accounted for in this analysis.
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Catches Historical sablefish landings were reconstructed from a variety of sources, and are generally more reliable than those for many other groundfish due to the consistent identification of sablefish by species. Uncertainty in historical landings (i.e., fish brought to market), primarily in the Washington-based fishery, stems from poor identification of fishing location (coastal U.S. waters, Canadian waters, or Alaskan waters). Given that sablefish are found from the southern tip of Baja Calfifornia to the north- central Bering Sea, fish landed in Washington ports are not necessarily caught off the coast of Washington. Revised reconstructions from California and Oregon, as well as a more limited analysis using Washington sources, for the 2011 assessment resulted in almost no change from landings used in previous sablefish assessments. Because discarding is explicitly modeled in the stock assessment, total catches (i.e., discards, drop offs, landings, etc.) are estimated simultaneously with other model parameters and derived quantities of management interest. Using an internal estimation approach, such as the one used here, can result in total mortality estimates that differ from those used by previous management and/or estimated using other methods. Sablefish landings were small (
