(2001 Stock Asessment Summary: part 6)
BSAI Other Red Rockfish
The other red rockfish complex is composed of
northern, sharpchin, rougheye, and shortraker
rockfish. For management purposes, these
species are managed in two groups: northern/sharpchin
and shortraker/rougheye. For each species, the
FABC was set at the maximum value allowable
under Tier 5, which is 75% of M.
Accepted values for M are rougheye
rockfish—0.025, shortraker rockfish—0.030, and
northern rockfish—0.060. Note that values
are not given for sharpchin rockfish because they
are at the edge of their range and are uncommon in
the BSAI. Multiplying these rates by the best
estimates of species-specific biomass gives the
following 2002 ABCs:
The 2002 OFL levels relative to
assuming identical species
complexes as used in 2001, are as follows:
Assessment authors conducted a detailed examination
of the available information for assessment of the
status of the other rockfish complex. Catch
distribution maps were created for the light dusky
rockfish and shortspine thornyhead complex.
The list of other rockfish was re-examined to
reveal that of the 28 species listed in the 2000
SAFE, only 7 species have been confirmed or
tentatively identified in catches from the BSAI.
These seven species include: dark dusky
rockfish, light dusky rockfish, harlequin rockfish,
red banded rockfish, redstripe rockfish, yelloweye
rockfish, and shortspine thornyhead. No
new biomass estimates were available for the 2002
assessment. Therefore, the recommended ABCs
and OFLs for 2002 were set equal to the 2001 values.
AI Atka Mackerel
New catch data and 2000 fishery age data were
incorporated into the AI Atka mackerel model.
The SSC has determined that this stock is
qualified for management under Tier 3 of the BSAI
Groundfish FMP. The updated point estimates of
from the present assessment are 124,500 t, 0.34, and
0.39, respectively. Projected spawning biomass
for 2002 is 118,000 t, placing Atka mackerel in
sub-tier “b” of Tier 3. The maximum FABC
value allowable under Tier 3b is F40%
adjusted (0.32). Projected harvesting at a
fishing mortality rate of 0.32 gives a 2002 catch of
71,300 t, which is the maximum permissible value of
ABC under Tier 3b. The assessment authors
recommend setting FABC
at a value of F52%
(0.21) would give a 2002 catch of 49,000 t.
Short-term projections under an average
fishing mortality rate equal to F52%
show that female spawning biomass will increase
above the estimated B40%
spawning biomass by 2003.
To apportion ABCs among areas, the authors used a
weighted average of the four most recent survey
estimates of the distribution of the biomass, which
gives the greatest weight to the 2000 survey.
When applied to the recommended ABC of 49,000
t, this formula gives the following subarea-specific
ABCs: Eastern Bering Sea and Eastern Aleutians
= 5,500 t (11.2%), Central Aleutians = 23,800 t
(48.5%), Western Aleutians = 19,700 t (40.2%).
The OFL was determined from the Tier 3b formula,
where an F35% adjusted
value of 0.37 gives a 2002 OFL of 82,300 t.
Model projections indicate that this stock is
neither overfished nor approaching an overfished
quarterly Oct-Dec 2001 sidebar
Auke Bay Lab