1. Widow Rockfish Assessment
Biology, Data, & History
NWFSC
Allan C. Hicks
Chantel R. Wetzel
STAR panel
July 27-31, 2015
Disclaimer: This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by NOAA Fisheries. It does not represent and should not be construed to represent any agency determination or policy

2. Widow Rockfish (Sebastes entomelas)
Elongated rockfish that is not bright red
Often called brownie or brown-bomber
Form dense midwater aggregations at night
Found near high relief or rocky areas
Diet primarily is from the deep scattering layer

3. NWFSC shelf/slope survey
Distribution
NWFSC shelf/slope survey
Northern Baja, Mexico to Southeast Alaska
More common Northern California to British Columbia
Typically 30 – 400 meters
Midwater or near bottom
Figure 11, Page 83

4. Ontogenetic movement
Smaller fish are found in shallower waters and more often in southern areas
Figure 12, Page 84

5. Ontogenetic movement
2008 cohort
2010 cohort
Figure 2, Page 74

6. Weight-at-length by source
Survey is tighter than fishery data, but seems unbiased
WCGOP data seem to be below. How are these collected?
Figure 40, Page 107

7. Length-at-age
Figure 46, Page 111

8. Ages observed (all data)
Figure 43, Page 109

9. Natural mortality a
Curves estimated from data using the equation C/Amax in log-space
M=c*Amax-1

10. Prior on M Based on a maximum age of 54
Lognormal distribution with a median of 0.081

11. Maturity-at-length Data from many years ago
Difference between CA and OR
CA, some rec
OR, all trawl
Figure 42, Page 108

12. Maturity-at-age Outliers not as obvious A more direct use in SS
Equal weight to OR and CA samples
Figure 42, Page 108 (note x-axis is Age)

13. Fishery for Widow Rockfish
Small amount of catch historically (trawl & long-line)
Trawl catches increased post-WW II
Foreign trawl vessels in late-1960s to early 1970s
The great Widow Rockfish hunt in the early 1980s
Trip limits throughout 1980s and 1990s
Declared overfished in 2001
Declared rebuilt in 2011

14. History of assessments
Workshop in late 1980 when the fishery was quickly expanding
Early assessments reported
relative biomass was less than 50% of unfished biomass
Potentially strong cohorts in late 1970s and/or early 1980s
Equilibrium yield around 10,000 mt
M was 0.15
1993 assessment
1980 and 1981 were strong cohorts
Different selectivity between bottom trawl and midwater trawl
1997 assessment
Defined fleet structure that was similar through 2011
Fishery supported by a small number of cohorts (1977, 78, 80, 81, and especially 1970)
Two area model divided at 43° N
M fixed at or 0.15
2011
Found that a one-area model produced similar results as the two-area model
Estimated sex-specific Ms with prior distributions
Medians of priors: and for females and males, respectively
𝑀 𝑓 = and 𝑀 𝑚 =0.1294

15. Latest assessment (2011)
Assessment in 2011 found widow rockfish recovered
Fleets separated by state and some gears
Historical WA landings a simple percentage of OR landings
Discards added to landings
6% historically, 16% recent, WCGOP most recent

16. Things of importance for the 2015 assessment
Include all useful data
Reconstruct Washington historical landings
Think about fleet definitions and selectivity
Investigate pattern in recruitment estimates
Recruitment deviation estimates from 2011 assessment

17. Fishery-dependent observations and data
Five fleets defined by strategy
Bottom trawl (data on discards)
Midwater trawl (some data on discards)
Hake fisheries (assume 100% retention)
Net (no data on discards, assume no discarding)
Hook-and-line (some data on discards)

18. Catches and landings Landing reconstruction was done for Washington
Worked with WDFW
Had to assume proportion of Widow in landing for some periods
Oregon and California have reconstructions done
At-sea enumerated separately
Foreign trawl vessels in 1960s and 1970s from Rogers
At-sea hake catch from A-SHOP (no discards)
Shoreside hake from PacFIN
Used catch of hake to partition from other groundfish hauls

19. Fishery indices Three gears, five indices
Hake and foreign at-sea same selectivity
Hake broken into two series (pre-1991/JV and post-91/domestic)
Same as were used in the 2011 assessment

20. Fishery length compositions
Bottom Trawl
Midwater Trawl
Hake

21. Fishery length compositions
Net
Hook-and-line

22. Fishery age compositions
Bottom Trawl
Midwater Trawl
Hake

23. Fishery age compositions
Net
Hook-and-line

24. Discard biomass
1980s: Pikitch data
1990s: EDCP data
2002+: WCGOP data

25. Discard length compositions
Pikitch Bottom Trawl
WCGOP

26. Fishery-independent data
SWFSC and NWFSC/PWCC Midwater Trawl Survey
Index of age-0 juveniles
AFSC/NWFSC triennial survey ( )
Length and biomass data
NWFSC shelf/slope survey ( )
Age, length, and biomass data

27. Juvenile survey Data and analysis from John Field
“Spatially rich” model
Years with coverage in northern areas

28. Triennial survey Strata GLMM with gamma distribution and ECE
Point Conception to US/Canadian border
Shelf and slope separate strata (183 m) to max of 400 m
GLMM with gamma distribution and ECE
Gamma distribution, random year/strata effects, ECEs

29. Triennial survey
Length compositions weighted by biomass in each stratum

30. NWFSC shelf/slope survey
Strata
Point Conception to 40.5 and 40.5 to US/Canadian border
Shelf and slope separate strata (183 m) to max of 400 m
GLMM with gamma distribution and ECE
Gamma distribution, random year/strata effects, ECEs

31. NWFSC shelf/slope survey
Length compositions weighted by biomass in each stratum

32. NWFSC shelf/slope survey
Marginal age compositions weighted by biomass in each stratum

33. NWFSC shelf/slope survey
Conditional age-at-length (unweighted)

34. NWFSC shelf/slope survey
Conditional age-at-length (unweighted)

35. Short list of management actions
1982: trip limits establish (75,000 lb)
1983: trip and per week limits (30,000 lb)
1987: only one landing per week above 3,000 lb
1990: halved trip limit
: limits reduced or periods extended
1994: limited entry and open access fisheries
2002: widow fishery mostly closed. RCA’s
2008: small monthly limits (1,500 lb)
2011: trawl rationalization began

36. Comparison to 2011 assessment
Weight-length

37. Comparison to 2011 assessment
Maturity

38. Comparison to 2011 assessment
Fleets
2011 Assessment
2015 Assessment CA OR WA
Bottom Trawl
Midwater Trawl
Shoreside Hake
BT & MW
At-sea Hake
Foreign Trawl
Net
No Catch
H&L
Recreational

39. Comparison to 2011 assessment
Length composition data
Initial input effective sample size calculation
A rough guide to how many fish sampled
Dependent on fleet structure

40. Comparison to 2011 assessment
Age composition data
Initial input effective sample size calculation
A rough guide to how many fish sampled
Dependent on fleet structure

41. Summary of data