168 
Fishery Bulletin 112(2-3) 
A 
B 
C 
Slope 
Cl 
oj 
O 
1000 2000 3000 4000 
Depth Mean 
CL 
<D 
O 
Depth Min 
CalCOFIa CalCOFIb SWFSC 
SurveyType 
PDO 
1000 2000 3000 4000 
Depth Mean 
co 
'-r 
csi 
O 
CO 
z 
LU 
(0 
ENSO 
Slope 
CD 
CL 
^ CM — 
CalCOFIa CalCOFIb SWFSC 
SeasAv 
SurveyType 
Quarter 
SurveyType 
Figure 5 
Generalized additive model functions of sightings per unit of survey effort 
in Southern California waters for (A) Risso’s dolphin ( Grampus griseus ), (B) 
striped dolphin (Stenella coeruleoalba), and (C) bottlenose dolphin (Tiirsiops 
truncatus) during cruises conducted by the NOAA Southwest Fisheries Sci- 
ence Center (SWFSC) and the California Cooperative Oceanic Fisheries In- 
vestigations (CalCOFI) from 1979 to 2009 in relation to sea-surface tempera- 
ture (SST) indices and depth variables in Southern California waters. Esti- 
mated degrees of freedom of the smooth function are given (in parentheses on 
they-axis) for all included variables. Solid lines represent the marginal effect 
of the given variable after controlling for the other variables in the model. 
The shaded band represents 2 standard errors. SurveyType is the variable 
for the cruises: SWFSC, CalCOFIa (1979-2004) and CalCOFIb (2004-2009). 
Variable abbreviations: DepthMin=minimum depth (m), DepthMean=mean 
depth (m), MaxDepth=maximum depth (m), SeasAv=seasonal averaged 
SST (°C), ENSO=El Nino-Southern Oscillation, and PDO=Pacific Decadal 
Oscillation. 
