336 
Fishery Bulletin 114(3) 
AUG SEP OCT NOV DEC 
Month 
AUG SEP OCT NOV DEC 
Month 
AUG SEP OCT NOV DEC 
Month 
Figure 4 
Monthly mean time series of (A) sea-surface temperature (SST), (B) 
chlorophyll-o (chl-a), (C) sea-surface height anomaly (SSHA), and (D) 
eddy kinetic energy (EKE) in the western North Pacific from August 
through December for the period 2005-2013. 
Table 4 
Summary statistics derived from the monthly models 
for the period 2005-2010. The base models were cali- 
brated with 70% of Pacific saury occurrence data, and 
values for the area under the curve (AUC) were calcu- 
lated from the remaining 30% of the occurrence data. 
The total number of fishing locations (N) is given for 
each month. All the models fitted significantly better 
than if they were fitted by chance (AUC>0.5). 
Month 
AUC 
N 
August 
0.907 
8074 
September 
0.910 
7411 
October 
0.912 
10,062 
November 
0.886 
5162 
December 
0.949 
429 
Table 5 
Heuristic estimates of the relative percent contribu- 
tion of environmental variables to models derived by 
using a maximum entropy approach. The 2 most impor- 
tant variables for each monthly model are presented in 
bold. SST=sea surface temperature; chl-a=chlorophyll- 
a; EKE=eddy kinetic energy; SSHA=sea-surface height 
anomaly. 
Environmental predictors 
Model 
SST 
Chl-a 
EKE 
SSHA 
August 
55.6 
7.1 
28.1 
9.2 
September 
56.8 
21.6 
14.4 
7.2 
October 
72.2 
5.9 
13.6 
8.3 
November 
73.2 
2.9 
9.4 
14.5 
December 
57.6 
0.8 
6.2 
35.4 
Prediction and validation of occurrence 
Maps of predicted HSI for August-December (2011- 
2013) are shown in Figure 6. In August, the predict- 
ed probability of occurrence of Pacific saury covered 
the entire Oyashio region, but it did so with a small 
value of HSI (Fig. 6, A-C). In September, high prob- 
ability areas (HIS >0.6) increased, especially east of 
Hokkaido and the Kuril Islands. The presence of fish- 
ing locations derived from OLS images also increased 
east of Hokkaido during this period (Fig. 6, D-F). In 
October, the known peak of the fishing season, a high 
