This is the age distribution graphic we have all see many times' It shows that since at least 2003,

1

• This is the age distribution graphic we have all
  see many times. It shows that since at least
  2003, Area 2 has had around 2-3 of 20 while
  Area 3 has 6-10 and area 4 even more. This age
  truncation is attributed to overharvest in area
  2. If this is true, the overharvest must have
  happened sometime between 1993 and 2003 when
  these fish were 10 to 20 yr olds and comprised
  the bulk of the fishery.

2
This is the harvest rate figure we have all seen.
Look at Area 2C between 1996 and 2002 when
overharvest leading to age truncation must have
been occurring. Harvest rates were between 19
and 30 with the average being around 25. In 3A
the harvest rates were between 18 and 24 with
the average around 22. This is too small a
difference in harvest rate to account for the
large difference in age 20 fish seen in the
first slide. So there likely are other factors
causing the age truncation.
3
Historical Trend 20
This figure shows long term data on age 20 by
area. 1998 marks the inflection point where Area
3 fish start to increase beyond Area 2. 1998
through 2003, shows the age gap widening and by
2003, the 20 are played out and begin to
decrease in Area 2. It is interesting to see that
the age gap is due to an increase in older fish
in Area 3 rather than a decreases in older fish
in Area 2.
4
77
80
83
80
77
77
83
83
80
At the workshop, Juan mentioned that there was
some evidence that the strong year classes on the
1980s distributed themselves more heavily in
western areas. The lower figures are from the
1998 Stock Assessment and plot the age 8
distribution across Areas. Note that the 67
through the large 77 year class distribute
themselves roughly 11 between Area 2(B C
total) and 3A. However, the strong 80 and 83
year classes distributed themselves almost 21 in
favor of Area 3A. The 87 year class was back to
the 11 ratio. The divergence in 20 age data
between Area 2 and 3A (top) tracks the
distribution of the 80 and 83 year classes as
they turn 20. Thus differential recruitment
between Area 2 and 3A of the 80 and 83 year
classes could be a significant factor in the age
truncation in Area 2, ..perhaps, more than
overharvest?
5
This variation in year class distribution is also
evident in the survey data. The survey shows
Area 2 (BC total) having a 11 Ratio with 3A
from 1998 to 2002. 2003 the ratio increased to
21, before falling back to 11 for 2004-2008.
The outlier is Area 3B which the survey shows
breaking from historical trends in 2004 and
begins to receive almost as many age 8 recruits
as areas 2B, 2C, and 3A combined!
6
Questions

• Does variability in recruit distribution across
  Areas account for some of the age truncation seen
  in area 2?
• Is there a pattern in how strong, average and
  weak year classes distribute themselves since
  1977?
• Can the age structure and spawning biomass
  distributions simulated by the widget be directly
  compared to observed levels without accurately
  accounting for recruitment variability over time?
• Is there any corroborating data which also shows
  the amazing increase in recruitment distribution
  seen in Area 3B since 2005? Is it real?