56 
Fishery Bulletin 116(1) 
Table 5 
Results of the stepwise procedure of discriminant analysis showing the order of 
standardized ( s ) morphometric variables to entry for (A) 3 geographic populations 
and (B) the female jumbo squid (Dosidicus gigas) sampled in 2009, 2013, and 2014 
off the Costa Rica Dome (CRD), off the Peruvian exclusive economic zone (PE), 
and in offshore waters of the central eastern Pacific (CEP). Correct cross-validated 
classification rates are shown in bold type. The morphometric variables are proos- 
tracum length (PL), conus length (CL), the maximum width of conus (CW), and the 
maximum width of prostracum (PW). At each step, the variable with the largest F 
value that exceeds the entry criteria is added. 
A 
Step no. 
Variable 
F 
dfl df 2 
P 
1 
PL S 
264.60 
2 559.00 
<0.01 
2 
CL S 
193.95 
4 1116.00 
<0.01 
3 
cw s 
151.85 
6 1114.00 
<0.01 
4 
PW S 
119.01 
8 1112.00 
<0.01 
Number and percentage of samples classified 
to a population 
Population 
CR 
PE 
CEP 
Total 
CR 
84 
18 
3 
105 
% 
80.0 
17.1 
2.9 
100 
PE 
62 
211 
9 
282 
% 
22.0 
74.8 
3.2 
100 
CEP 
14 
14 
147 
175 
% 
8.0 
8.0 
84.0 
100 
Total correct (%) 
78.6 
B 
Step no. 
Variable 
F 
dfl df 2 
P 
1 
PLs 
331.32 
2 372.00 
<0.01 
2 
CLs 
204.84 
4 742.00 
<0.01 
3 
CWs 
165.34 
6 740.00 
<0.01 
4 
PWs 
129.74 
8 738.00 
<0.01 
Number and percentage of samples classified 
to a population 
Population 
CR 
PE 
CEP 
Total 
CR 
72 
14 
3 
89 
% 
80.9 
15.7 
3.4 
100 
PE 
39 
141 
4 
184 
% 
21.2 
76.6 
2.2 
100 
CEP 
3 
0 
99 
102 
% 
2.9 
0 
97.1 
100 
Total correct (%) 
83.2 
there is reason to believe that our SDA results can 
be explained by these environmental differences. For 
example, the Costa Rica Dome (Fig. 2) is an oceanic 
upwelling center where the thermocline is shallow 
(Sasai et ah, 2007), whereas the waters off Peru (PE) 
are primarily affected by the cold northward flowing 
Humboldt Current and are associated with strong up- 
welling of cool subsurface waters (Chavez et ah, 2008). 
Individuals in the CEP were from an area primarily 
influenced by a warm Equatorial Counter Current and 
the cooler South Equatorial Current (Fig. 2). The dif¬ 
ferences in oceanographic conditions in each region 
may consequently result in morphometric variations in 
the gladius. For example, several studies have shown 
that ambient temperature has a significant influence 
on the growth and development of D. gigas (Keyl et al., 
