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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

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

introduction biology
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
introduction fishery
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
slide6

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
triennial shelf survey
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

afsc slope s urvey
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

nwfsc survey
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

survey post stratification
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

survey stratification for glmm glm
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)

model based biomass indice s
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
slide25

AFSC Triennial

AFSC slope

NWFSC slope

NWFSC shelf-slope

slide27

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
biological data maturity at length
Biological Data – Maturity at length
  • Oregon
  • Thomson and

Hannah 2010

natural mortality
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)
discard data
Discard data
  • 1985-1987 Pikitch data
  • 2002-2011 WCGOP data
ageing precision and bias
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)
ageing error methods
Ageing Error Methods
  • Punt et al. 2008; simulation tested
  • Assumes one reader is unbiased
  • N = 898
base model
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
estimated parameters1
Estimated parameters

Total: 44 + 95 recruitment deviations =139 estimated parameters

tuning lengths ages and recruitment bias adjustment
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
survey abundance
Survey abundance

q=0.64q0.94

survey abundance1
Survey abundance

q=0.53q=1.13

survey lengths1
Survey lengths

Triennial Lengths

NWFSC Shelf/Slope Lengths

AFSC Slope Lengths

M

F

M

F

M

F

fishery discarded lengths
Fishery discarded lengths

Unsexed Female Male

catch estimates
Catch Estimates

Landings DiscardCatch

biomass trajectory
Biomass trajectory

Total Biomass

biomass trajectory1
Biomass trajectory

Spawning Biomass Depletion

management performance
Management Performance
  • Current: Minor slope rockfish complex

North of 40.10

South of 40.10

sensitivities base case
Sensitivities- Base case
  • Low sensitivities
  • Ageing error
  • Maturity
  • Scale sensitivity
  • M ( )
  • Fecundity ( )
  • Marg. ages ( )
  • Sel. blocks ( )
  • Status sensitivity
  • M ( )
  • Marg. Ages ( )
  • Sel. blocks ( )
sensitivities likelihood components
Sensitivities- Likelihood components

Red line: Base case

SB0

Depletion

Spawning biomass

SB2013

0.5

2

0.5

2

Survey

-Wt.

Lt.

-Lt.

Age

0.5

2

0.5

2

Survey

-Wt.

Lt.

-Lt.

Age

summary likelihood profile components
Summary: Likelihood profile components
  • Lt comps:
    • Base case: all consistent
    • BC +M est: Trawl inconsistent
  • Age comps:
    • All profiles: Trawl and NWFSC opposing at higher M
  • Indices:
    • All profiles: all consistent
summary
Summary
  • Aurora depletion at 65%
  • Scale is greater than DB-SRA model
  • Natural mortality is important axis of uncertainty