Errata 
Page 355: Figure 4 should read as follows: 
Fishery Bulletin tt0:344-360 (2012). 
Barlow, Paige F., and Jim Berkson 
Evaluating methods for estimating rare 
events with zero-heavy data: a simulation 
model estimating sea turtle bycatch in the 
pelagic longlme fishery 
Corrections: 
Page 354. The last paragraph in the 
right column should read as follows: 
The GLMs only outperformed the 
delta-lognormal methods in the 
fully uniform scenario ( Turtles , 
J uniform 7 
Sets , ). In this spatial scenario, the 
GLMs were the most accurate esti- 
mation method, but they produced 
more positive outliers. The co-occur- 
rence clumping scenario (Turtles clump , 
Sets . , „ ) was the only spa- 
tial scenario in which the GLMs 
did not produce more outliers than 
the delta-lognormal methods. The 
GLMs were biased lower than 
the delta-lognormal methods in 
the co-occurrence clumping scenario 
( Turtle , , Sets . , ) and sets- 
only clumping scenario (Turtles , , 
u r ° unilorm 7 
Sets . . ). No substantial differ- 
clump-sets 
ence was seen between GLM-P and 
GLM-NB performance in any spatial 
scenario. 
Page 357. The third paragraph in the 
right column should read as follows: 
The GLMs were more accurate than 
the delta-lognormal methods in the 
fully uniform scenario (Turtles , 
Sets uniform^ because this spatial sce- 
nario was the only one that did not 
violate the GLM-P assumption that 
counts are independent and randomly 
distributed in space (McCracken 2004, 
Sileshi 2006). 
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Figure 4 
Comparison of bycatch estimates to the total amount of bycatch simulated 
to evaluate performance of estimation methods. The stratum-level delta- 
lognormal method (D-s), delta-lognormal method for all sets pooled (D-p), 
generalized linear model with Poisson error distribution for all sets pooled 
(P-p), and generalized linear model with negative binomial error distri- 
bution for all sets pooled (NB-p) were evaluated. Each of the 5 panels 
corresponds to one of the spatial scenarios: ( A)=co-occurrence clumping 
(Turtles , , Sets . , ), (B)=sets-only clumping (Turtles , , Sets , 
clump’ clump-turtles 7 J r- o uniform 7 clump- 
sets ), (C ^independent clumping (Turtles c| , Sets dump sels ), (D)=turtles-only 
clumping (Turtles , , Sets , ), and (E)=fully uniform (Turtles , , Set- 
s um f orm ). Each of the plots within a panel corresponds to an estimation 
method. The scale of the y-axes varies by rows of panels for display pur- 
poses. The horizontal line at a relative error of zero marks where the 
median of an unbiased estimation method should fall. Notches are placed 
around the medians, and if the notches of 2 plots do not overlap, there is 
strong evidence that those medians differ. The box of each plot includes 
the first through third quartile. Whiskers extend to the most extreme 
data point that is no more than 1.5 times the interquartile range from the 
box. Small circles represent outliers. For purposes of display, in the panel 
for the sets-only clumping scenario (Turtles , , Sets , , ), one outlier 
was removed from each of the P-p and NB-p box plots. 
