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Status of Aurora Rockfish off of the U.S. West Coast in 2013. Owen Hamel 1 , Jason Cope 1 , Sean Matson 2 1 NOAA NWFSC, Seattle 2 NOAA NWR, Seattle July 2013. Introduction - Biology. Sebastes aurora – long lived rockfish (>100 yrs ) British Columbia to Baja California

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Status of Aurora Rockfish off of the U.S. West Coast in 2013


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    1. Status of Aurora Rockfish off of the U.S. West Coast in 2013 Owen Hamel1, Jason Cope1, Sean Matson2 1NOAA NWFSC, Seattle 2NOAA NWR, Seattle July 2013

    2. Introduction - Biology • Sebastes aurora – long lived rockfish (>100 yrs) • British Columbia to Baja California • Vast majority 350-550 m depth • No genetic work to indicate multiple stocks • There is a gradient in growth with latitude

    3. Catch rates: NWFSC 2003-2012

    4. Mean fish length vsdepth and latitude

    5. Introduction - Fishery • Caught incidentally with other rockfish fish and Sablefish/Dover sole/Thornyhead complex • Associated with splitnose; called “rosefish” in CA • Minimal catch prior to 1960s • Caught in NW by foreign fleet in the late 1960s-1970s • Mostly bottom trawl caught, some in other gears. • Largest catches in 1980s and 1990s

    6. Introduction – Management • Historical: little management attention • Exploitation rate estimated as “high” in 1990s (Rogers et al. 1996) • Current: Minor slope rockfish complex • 1999: Sebastes complexes N/S 40°10’N. • 2000: Slope complex trip limits • 2002: Rockfish Conservation Areas: shallower; perhaps pushed fishing into aurora habitat. • 2011: IFQ/Catch Shares

    7. Landings History

    8. Surveys

    9. Triennial Shelf Survey 1977 (generally excluded) No aurora data Depth: 91-457 meters 1980-1992 No aurora data – too shallow Depth: 55-366 meters 1995-2004 Aurora data. Depth: 55-500 meters Conducted by RACE until 2004 when done by FRAM Random trawls on systematic line transects

    10. Triennial Survey Timing

    11. AFSC Slope Survey 1984, 1988, 1990-1993, 1995-1996 Not used Limited latitudinal coverage Depth: 183-1200 meters 1997, 1999-2001 used for aurora. Pt. Conception to Canadian Border Depth: 183-1200 meters Random trawls on systematic line transects

    12. NWFSC survey 1999-2002 surveyed 183-1280 meters Did not go south of Pt. Conception until 2002 Did not collect aurora rockfish lengths or otoliths Random trawls on systematic line transects 2003-2012 (and beyond) 55-1280 meters 32.5° to 48.17° Random trawl locations Vessels chosen each year

    13. Survey post-stratification Did not post-stratify by depth using fish length Ontogenetic movement to deeper water But also change in length at age with latitude Did not find any consistent break points

    14. Survey stratification for GLMM/GLM Strata collapsed to satisfy condition of at least 3 positive observations in each year/area/depth stratum Depths Triennial: 300-500 meters ; 40.5◦ NLat. Lengths AFSC slope: 300-549 meters ; 40.5◦ NLat. Lengths NWFSC slope: 300-549 meters ; 40.5◦ NLat. NWFSC: 300-549 meters (40.5◦ N, 34.5◦ NLat.); 549-600 meters (32-37.5◦ NLat.) Lengths Ages Maturity (2012)

    15. Catch rates: Triennial shelf survey

    16. Catch rates: AKFSC slope survey

    17. Catch rates: NWFSC slope survey

    18. Catch rates: NWFSC shelf/slope survey

    19. Model based biomass indices • Delta-GLMM • NWFSC: random year:vessel effects • Triennial, AFSC Slope: NO random vessel effects • Fixed effects: year, strata, depth, year:strata • Gamma errors • MCMC’s to determine variability

    20. Model selection – Triennial survey

    21. Model selection – AFSC slope survey

    22. Model selection – Triennial survey

    23. Model selection – Triennial survey

    24. AFSC Triennial AFSC slope NWFSC slope NWFSC shelf-slope

    25. Survey biomass indices

    26. Age and length composition data • Length data • All lengths below 20 cm are modeled independent of sex • Trennial, AFSC slope and NWFSC shelf/slope survey • Trawl and Non-Trawl fisheries • Both sex-specific and combined sex length frequencies • Both landed and discard length frequencies • Age data • Included as conditional age-at-length data • Ages 8 and below are combined sex data • NWFSC shelf/slope survey and Trawl Fishery

    27. Triennial shelf survey length frequencies

    28. AFSC slope survey length frequencies

    29. NWFSC survey length frequencies

    30. Trawl fishery length frequencies

    31. Trawl fishery length frequencies

    32. Trawl discard length frequencies

    33. Non-Trawl fishery length frequencies

    34. Non-Trawl discard length frequencies

    35. NWFSC survey conditional age-at-length data

    36. Trawl fishery conditional age-at-length data

    37. Biological Data - Weight-Length • NWFSC Survey data

    38. Biological Data – Maturity at length • Oregon • Thomson and Hannah 2010

    39. Natural Mortality • Hoenig’s Method with prior/prediction interval ~0.04 - max age of 125 (F), 118 (M) • 0.0405 (F - mean value of prior) • 0.0429 (M – mean value of prior)

    40. Discard data • 1985-1987 Pikitch data • 2002-2011 WCGOP data

    41. Ageing Precision and Bias • 1 Lab, 1 method, 2 readers • Cooperative Ageing Lab , Break and Burn • OR and CA commercial (2003, 2008, 2009), • NWFSC Survey (2003, 2005, 2007, 2009-2012)

    42. Ageing Error Methods • Punt et al. 2008; simulation tested • Assumes one reader is unbiased • N = 898

    43. DataSummary

    44. Base model • Coast-wide model • 3 fleets – Trawl, Non-Trawl and Full Retention • Sex-specific • Fisheries: asymptotic selectivities • Surveys: dome-shaped selectivities • Blocks on retention for Trawl fleet • Estimate growth • Composition effective sample sizes tuned

    45. Estimated parameters

    46. Estimated parameters Total: 44 + 95 recruitment deviations =139 estimated parameters

    47. Tuning: Lengths, Ages and Recruitment Bias Adjustment Downweighting input N Bias adjustment • Lengths • Trawl: 0.4 • Non-Trawl: 0.7 • Triennial: 0.9 • Ages • Trawl: 0.7

    48. Results

    49. Growth