Syah et al.: Predicting potential fishing zones for Cololabis saira 
333 
Table 1 
Number of images from the Operational Linescan System of the U.S. Defense Meteorological Satel- 
lite Program for the period 2005-2013, by month and year, that were used in this study to predict 
fishing locations of Pacific saury (Cololabis saira) in the western North Pacific. 
Month 
2005 
2006 
2007 
2008 
2009 
2010 
2011 
2012 
2013 
August 
37 
24 
14 
0 
0 
15 
15 
12 
4 
September 
44 
43 
9 
2 
7 
27 
17 
29 
17 
October 
67 
70 
55 
3 
11 
47 
36 
33 
31 
November 
72 
53 
69 
16 
16 
43 
34 
27 
36 
December 
51 
31 
21 
1 
10 
30 
43 
22 
20 
squid. In this study, we used SST to 
distinguish between the lights of the 
vessels that fish for Pacific saury and 
those of other fishing vessels because 
Pacific saury prefers colder areas for 
their migration routes (Saitoh et al., 
1986) and this approach was used 
earlier by Mugo et al. (2014). 
Because Pacific saury are dis- 
tributed below the upper SST limit 
(Table 3), we split the nighttime light 
images into 2 categories. All lights 
that occurred above the upper SST 
limit were categorized as lights re- 
lated to squid fishing, and all lights 
that occurred below this limit were 
assumed to be from vessels fishing 
for Pacific saury. Consequently, only 
the locations of lights that indicated 
fishing for Pacific saury were used 
for our habitat modeling procedures. 
Environmental data 
We used satellite-derived data — chl- 
a, SST, eddy kinetic energy (EKE), 
and sea-surface height anomaly 
(SSHA) — from 2005 through 2013 as 
environmental factors in the maxi- 
mum entropy models. Daily chl-a 
and SST values were derived from 
satellite images from the Moder- 
ate Resolution Imaging Spectroradi- 
ometer (MODIS)-Aqua mission and 
were downloaded from NASA God- 
dard Space Flight Center [website]. 
These data were processed with the 
SeaDAS package, vers. 6.4 (NASA 
Goddard Space Flight Center, Green- 
belt, MD) and reprocessed to create 
maps with a 1-km resolution. 
Daily SSHA and geostrophic ve- 
locities (u, v) from the Topex/Posei- 
don and ERS-1/2 altimeters were 
20 
18 
16 
14 
12 
lllllillll 
20 B 
18 
16 
18 
16 
14 
12 
10 
8 
6 
4 
2 I 
0 ■ 
llllllllu... 
10 20 
10 20 30 40 50 60 
Digital number value 
Figure 2 
Histograms of the relative frequency of visible pixels derived from monthly 
composite images obtained from the western North Pacific from the Opera- 
tional Linescan System of the U.S. Defense Meteorological Satellite Pro- 
gram for (A) August, (B) September, (C) October, (D) November, and (E) 
December for the period 2005-2013 
