Henderson et al.: Effects of sea-surface temperature on the occurrence of small cetaceans off Southern California 
169 
B 
1000 
2000 3000 4000 
Depth Max 
500 1000 
2000 
Slope 
3000 
500 1000 
2000 
Slope 
3000 
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1000 2000 3000 4000 
Depth Mean 
1000 2000 3000 
DepthMean 
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CalCOFIa CalCOFIb SWFSC 
SurveyType 
SeasAv 
CalCOFIa CalCOFIb SWFSC 
SurveyType 
Figure 6 | 
Generalized additive model func- J 
tions of sightings per unit of effort 5 
from 1979 to 2009 of (A) northern 76 
right whale dolphin (Lissodelphis <5 
borealis), (B) Dali’s porpoise ( Pho - 
coenoides dalli), and (C) Pacific 
white-sided dolphin (Lagenorhyn- 
chus obliquidens ) in relation to 
sea-surface temperature (SST) in- £ 
dices and depth variables in South- g- 
ern California waters. Estimated 2 
degrees of freedom of the smooth ^ 
function are given (in parenthe- £ 
ses on the y-axis) for all included e 
03 
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 (2004-09). 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. 
CalCOFIa CalCOFb SWFSC 
SurveyType 
