Wetzel et al.: The effect of reduced data on monitoring overfished fish stocks 
197 
Full data 
~\ i i i i 
50 74 98 122 146 
Reduced data Eliminated data 
CD 
c n 
0) 
> 
CD 
O' 
LU 
cr 
1.5 
1.0 
0 5 
0.0 
-0 5 
D 
iilllllilmiiini 
IfffffiffnTnTnr 
h-1-1-1-1— 
50 74 98 122 146 
1.5 
1.0 
0.5 
0.0 
-0.5 
Assessment year 
Figure 3 
Relative error (RE) of estimated spawning biomass (SB) and relative SB, estimates 
of steepness, size at maximum selectivity, and the width at maximum selectivity in 
each assessment year for the time-invariant case and all 3 data scenarios (full data, 
reduced data, and eliminated data) for all simulations used to examine the effect 
of data availability on the ability to monitor rebuilding of an overfished stock of a 
rockfish species. The eliminated data scenario in the absence of composition data had 
selectivity fixed at the asymptotic assumption and hence did not estimate the width 
at maximum selectivity parameter. The percentage of stocks that had rebuilt to the 
target biomass during the management period (shown in bottom panels) within the 
operating model (OM, solid black line) and the estimation method (EM, dashed black 
line); data collection consequently returned to historical levels when the EM deter¬ 
mined that the stock was rebuilt. The black lines in the gray boxes denote the median 
of the estimates, the gray boxes cover the 25-75% simulation interval, and the boxplot 
whiskers indicate the 95% simulation interval for each assessment year. 
