Staaf et a!. : Distribution of ommastrephid paralarvae in the eastern tropical Pacific 
83 
A 
B 
Paralarvae/m 3 
I 1 0—0. 1 6 
I 1 0.16-0.25 
| 1 0.25—0.3 
[ I 0.3-0. 4 
Dr: 0 . 4 - 0.55 
r "I 0.55 -0.82 
I 0 82-1 3 
SI 1.3-2. 1 
20 N 
Figure 2 
Abundance of paralarval purpleback squid ( Sthenoteuthis oualaniensis) and jumbo squid ( Dosidicus gigas) from ail 
study years (1998-2006) for (A) manta (surface) and (B) bongo (oblique) tows conducted in the eastern tropical Pa- 
cific. Paralarval abundance was interpolated by using inverse distance weighting with a cell size of 1° and a fixed 
search radius of 5°. 
Table 1 
Generalized linear models used to relate the presence and absence of ommastrephid paralarvae in manta 
(surface) and bongo (oblique) tows conducted in the eastern tropical Pacific in 1998-2006 to 5 in situ oceano- 
graphic variables: sea-surface temperature (SST), sea-surface salinity (SSS), mixed-layer depth (MLD), tem- 
perature at thermocline (TT), and surface-concentration of chlorophyll-a (CHL). A stepwise approach selected 
SST, SSS, and TT for the final manta model; SST and MLD were selected for the final bongo model. Better- 
fitting models have a higher percentage of explained deviance and a lower Akaike’s information criterion 
(AIC) value. 
Manta 
Model 
Deviance (%) 
AIC 
Null 
913 
SST x SSS x TT 
18.8 
748.1 
SST x TT 
18.5 
748.5 
SST x SSS 
18.4 
749.6 
SSS x TT 
12.7 
801.6 
SST 
18.1 
750.2 
SSS 
4.6 
873.1 
TT 
11 
814.9 
Bongo 
Model 
Deviance (%) 
AIC 
Null 
710.3 
SST x MLD 
12.2 
627.7 
SST 
10.6 
637.1 
MLD 
0.2 
711.1 
