Hulson et a!.: Distribution of sampling effort for age composition of multiple species 
333 
A SGI 
C SG 2 
0.8 - 
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m 
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Combined 
□ Roundfish 
□ Flatfish 
61 Rockfish 
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Species (region) 
Figure 1 
Proportion of total age-composition sample size for the (A, C, E, G) combined species types and (B, 
D, F, H) individual species investigated under proportional allocation (PA) sampling across the 4 
sampling goals (SG1-4) by using data from the NOAA Alaska Fisheries Science Center bottom trawl 
surveys for the Gulf of Alaska (GOA, 1984-2011), Aleutian Islands (AI, 1980-2010), and Bering Sea 
(BS, 1982-2011). Species acronyms are explained in Table 1. Note the different scale values on the 
y axis: the left side designates the proportion of total sample size combined across species types; the 
right side designates values for individual species. 
general, of similar magnitude between SRS and propor- 
tional allocation sampling across the sampling goals. 
Both SRS and proportion sampling required almost 
half the number of age samples to achieve the same 
amount of uncertainty as that obtained with fixed al- 
location, which is the current method for the majority 
of species sampled by the AFSC bottom trawl survey. 
Compiled results of the estimated sample sizes sam- 
pling goals investigated are shown in Table 2 to reduce 
the number of results presented; the estimated sample 
sizes for each species investigated across the sampling 
goals, sampling methods, and whether or not aging er- 
ror was included are provided in Supplementary Tables 
3-5 (online only). 
Step 2: sample size for determining age composition and 
SCAA model uncertainty 
The CV of total biomass in the final year of the es- 
timation models for flatfish, rockfish, and roundfish 
decreased at different rates with increasing age-com- 
position sample size from survey data and eventually 
