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Highlights from Regional Assessment Methods
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Political Science

Report on the 2018 International Sablefish Workshop

Profile image of Aaron BergerAaron Berger

2019

https://doi.org/10.25923/SFC9-MP92
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118 pages

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Abstract

the NOAA Technical Memorandum series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible. Documents within this series reflect sound professional work and may be referenced in the formal scientific and technical literature.

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References (43)

  1. Cope, J. M., and A. E. Punt. 2009. Drawing the lines: Resolving fishery management units with simple fisheries data. Can. J. Fish. Aquat. Sci. 66:1256-1273.
  2. Cox, S. P., and A. R. Kronlund. 2008. Practical stakeholder-driven harvest policies for groundfish in British Columbia, Canada. Fish. Res. 94:224-237.
  3. Cox, S. P., and A. R. Kronlund. 2009. Evaluation of interim harvest strategies for sablefish (Anoplopoma fimbria) in British Columbia, Canada for 2008/09. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/042. vi + 82 p.
  4. Cox, S. P., A. R. Kronlund, and M. R. Wyeth. 2009. Development of precautionary management strategies for the British Columbia sablefish (Anoplopoma fimbria) fishery. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/043. vi + 145 p.
  5. Cox, S. P., A. R. Kronlund, and L. Lacko. 2011. Management procedures for the multi-gear sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada. DFO Can. Sci. Advis. Sec. Res. Doc. 2011/063. viii + 45 p.
  6. Cox, S. P., K. Holt, and S. Johnson. In press. Evaluating the robustness of management procedures for the sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada for 2017-18.DFO Can. Sci. Advis. Sec. Res. Doc.
  7. DFO (Fisheries and Oceans Canada). 2006. A harvest strategy compliant with the Precautionary Approach. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2006/023.
  8. DFO. 2009. A Fishery Decision-Making Framework Incorporating the Precautionary Approach. Available at http://www.dfo-mpo.gc.ca/reports-rapports/regs/sff-cpd/precaution- eng.htm.
  9. DFO. 2014. Performance of a revised management procedure for sablefish in British Columbia. DFO Can. Sci. Advis. Sec. Sci. Rep. 2014/025.
  10. DFO. 2016. A revised operating model for sablefish (Anoplopoma fimbria) in British Columbia, Canada. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2016/015.
  11. DFO. 2017. Evaluating the robustness of management procedures for the sablefish (Anoplopoma fimbria) fishery in British Columbia, Canada for 2017-18. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2017/017.
  12. Echave, K. B., D. H. Hanselman, M. D. Adkison, and M. F. Sigler. 2012. Interdecadal change in growth of sablefish (Anoplopoma fimbria) in the northeast Pacific Ocean. Fish. Bull., U.S. 110:361-374.
  13. Echave, K. B., C. J. Rodgveller, and S. A. K. Shotwell. 2013. Calculation of the geographic sizes used to create population indices for the Alaska Fisheries Science Center longline survey. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-253, 93 p.
  14. Fournier, D. A., H. J. Skaug, J. Ancheta, J. Ianelli, A. Magnusson, M. N. Maunder, A. Nielsen, and J. Sibert. 2012. AD Model Builder: using automatic differentiation for statistical inference of highly parameterized complex nonlinear models. Optim. Methods Softw. 27:233-249.
  15. Hanselman, D. H., W. G. Clark, J. Heifetz, and D. M. Anderl. 2012. Statistical distribution of age readings of known-age sablefish (Anoplopoma fimbria). Fish. Res. 131:1-8.
  16. Hanselman, D. H., C. R. Lunsford, and C. J. Rodgveller. 2014. Assessment of the sablefish stock in Alaska. In Stock assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska. North Pacific Fishery Management Council, 605 West 4th, Suite 306 Anchorage, Alaska 99501, 142 p.
  17. Hanselman, D. H., J. Heifetz. K. B. Echave, and S. C. Dressel. 2015. Move it or lose it: Movement and mortality of sablefish tagged in Alaska. Can. J. Fish. Aquat. Sci. 72(2):238-251.
  18. Hanselman, D. H., C. R. Lunsford, C. J. Rodgveller, and M. J. Peterson. 2016. Assessment of the sablefish stock in Alaska. In Stock assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska. North Pacific Fishery Management Council, 605 West 4th, Suite 306 Anchorage, Alaska 99501, 164 p.
  19. Hanselman, D. H., C. J. Rodgveller, C. R. Lunsford, and K. H. Fenske. 2017. Assessment of the sablefish stock in Alaska. In Stock assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska. North Pacific Fishery Management Council, 605 West 4th, Suite 306 Anchorage, Alaska 99501, 176 p.
  20. Head, M. A., A. Keller, and M. Bradburn. 2014. Maturity and growth of sablefish, Anoplopoma fimbria, along the U.S. West Coast. Fish. Res. 159:56-67. doi: 10.1016/j.fishres.2014.05.007.
  21. Head, M. A., G. L. Stokes, J. Thorson, and A. Keller. 2016. Techniques for improving estimates of maturity ogives in groundfish using double-reads and measurement error models. Fish. Res. 179:251-258. doi: 10.1016/j.fishres.2016.03.004.
  22. Jasonowicz, A. J., F. W. Goetz, G. W. Goetz, and K. M. Nichols. 2017. Love the one you're with: Genomic evidence of panmixia in the sablefish (Anoplopoma fimbria). Can. J. Fish. Aquat. Sci. 74:377-387.
  23. Johnson, K. F., M. B. Rudd, M. Pons, C. A. Akselrud, Q. Lee, F. Hurtado-Ferro, M. A. Haltuch, and O. S. Hamel. 2015. Status of the U.S. sablefish resource in 2015. Pacific Fishery Management Council. 7700 Ambassador Place NE, Suite 200, Portland, OR 97220, 377 p.
  24. Jones, M. K., and S. Cox. 2018. Size-selectivity for British Columbia sablefish (Anoplopoma fimbria) estimated from a long-term tagging study. Fish. Res. 199:94-106.
  25. Methot, R., and C. R. Wetzel. 2013. Stock synthesis: A biological and statistical framework for fish stock assessment and fishery management. Fish. Res. 142: 86-99.
  26. NMFS. 2000. Japanese supply and market for sablefish. U.S. Dep. Commer., NOAA Tech. Memo. NOAA-TM-NMFS-SWR-037, 68 p.
  27. Punt, A. E., K. KrusicGolub, and S. Roberston. 2008. Quantifying age-reading error for use in fisheries stock assessments, with application to species in Australia's southern and eastern scalefish and shark fishery. Can. J. Fish. Aquat. Sci. 65:1991-2005.
  28. Sigler, M. F. 2000. Abundance estimation and capture of sablefish (Anoplopoma fimbria) by longline gear. Can. J. Fish. Aquat. Sci. 57: 1270-1283. 22-inch minimum size limit north of Point Conception (allowance for some smaller fish). 1990-1993 Increasingly shorter fixed-gear seasons. 1997-1999 Sequential reductions in landings limits begin.
  29. 14,552 21,310 18,030 18,030 Pot fishing ban repealed in Bering Sea for June 1-30 (74 FR 28733).
  30. 10,973 16,128 13,657 13,657 NPFMC passes Amendment 101 to allow pot fishing in the GOA 10,257 13,397 11,795 11,795 Whale depredation accounted for in survey and fishery 10,670 15,428 13,083 13,083 Pot fishing begins in the GOA Sean Cox Simon Fraser University (604) 291-5778 spcox@sfu.ca Kyle Hebert ADF&G -Juneau (907) 465-4228 kyle_hebert@fishgame.state.ak.us James Hastie NWFSC - Montlake (206) 860-3412 jim.hastie@noaa.gov Rob Kronlund Fisheries and Oceans Canada (250) 756-7108
  31. Kronlunda@pac.dfo-mpo.gc.ca
  32. WyethM@pac.dfo-mpo.gc.ca RECENT TECHNICAL MEMORANDUMS Copies of this and other NOAA Technical Memorandums are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22167 (web site: www.ntis.gov). Paper and electronic (.pdf) copies vary in price.
  33. LANG, C. A., J. I. RICHAR, and R. J. FOY. 2019. The 2018 eastern Bering Sea continental shelf and northern Bering Sea trawl surveys: Results for commercial crab species, 220 p. NTIS No. PB2019-100298.
  34. JEFFERSON, T. A., M. E. DAHLHEIM, A. N. ZERBINI, J. M. WAITE, and A. S. KENNEDY. 2019. Abundance and seasonality of Dall's porpoise (Phocoenoides dalli) in Southeast Alaska, 45 p. NTIS No. PB2019-100297.
  35. RUSSELL, J. R., S. C. VULSTEK, J. E. JOYCE, R. P. KOVACH, and D. A. TALLMON. 2018. Long-term changes in length at maturity of Pacific salmon in Auke Creek Alaska, 28 p. NTIS No. PB2019-100295.
  36. LEW, D. K., and J. LEE. 2018. Costs, earnings, and employment in the Alaska saltwater sport fishing charter sector, 2015, 85 p. NTIS No. PB2019-100296.
  37. MCKELVEY, D., and K. WILLIAMS. 2018. Abundance and distribution of age-0 walleye pollock in the eastern Bering Sea shelf during the Bering Arctic Subarctic Integrated Survey (BASIS) in 2014, 48 p. NTIS No. PB2018-101437.
  38. BRYAN, D. R., M. LEVINE, and S. MCDERMOTT. 2018. Results of the 2016 and 2017 Central and Western Aleutian Islands underwater camera survey of Steller sea lion prey fields, 87 p. NTIS No. PB2018-101436.
  39. SEUNG, C. K., and S. MILLER. 2018. Regional economic analysis for North Pacific fisheries, 86 p. NTIS No. PB2018-101435.
  40. GANZ, P., S. BARBEAUX, J. CAHALAN, J. GASPER, S. LOWE, R. WEBSTER, and C. FAUNCE. 2017. Deployment performance review of the 2016 North Pacific Groundfish and Halibut Observer Program, 68 p. NTIS No. PB2018-101537.
  41. M. M. MUTO, V. T. HELKER, R. P. ANGLISS, B. A. ALLEN, P. L. BOVENG, J. M. BREIWICK, M. F. CAMERON, P. J. CLAPHAM, S. P. DAHLE, M. E. DAHLHEIM, B. S. FADELY, M. C. FERGUSON, L. W. FRITZ, R. C. HOBBS, Y. V. IVASHCHENKO, A. S. KENNEDY, J. M. LONDON, S. A. MIZROCH, R. R. REAM, E. L. RICHMOND, K. E. W. SHELDEN, R. G. TOWELL, P. R. WADE, J. M. WAITE, and A. N. ZERBINI. 2018. Alaska marine mammal stock assessments, 2017, 272 p. NTIS No. PB2018-101535.
  42. RICHWINE, K. A., K. R. SMITH, and R. A. MCCONNAUGHEY. 2018. Surficial sediments of the eastern Bering Sea continental shelf: EBSSED-2 database documentation, 48 p. NTIS No. PB2018-101013.
  43. DORN, M. W., C. J. CUNNINGHAM, M. T. DALTON, B. S. FADELY, B. L. GERKE, A. B. HOLLOWED, K. K. HOLSMAN, J. H. MOSS, O. A. ORMSETH, W. A. PALSSON, P. A. RESSLER, L. A. ROGERS, M. A. SIGLER, P. J. STABENO, and M. SZYMKOWIAK. 2018. A climate science regional action plan for the Gulf of Alaska, 58 p. NTIS No. PB2018-

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