180 
Fishery Bulletin 111(2) 
-10°S 
-15°S 
-10°S 
-1 5°S 
-10°S 
-1 5°S 
1 05°E 1 1 0°E 1 15°E 1 20°E 125°E 105°E 110°E 115°E 120°E 125°E 
Figure 3 
On the left, images of mean values for 3 months obtained from remotely sensed data of the eastern 
Indian Ocean off Java during El Nino event (September, October, and November 1997) for 3 parame- 
ters — (A) sea-surface-height anomaly (SSHA), (B) sea-surface temperature (SST), and (C) chlorophyil- 
o (chl-a) concentration. On the right, images of mean values for 3 months obtained during La Nina 
event (February, March, and April 1999) for the same 3 parameters: (D) SSHA, (E) SST, and (F) chl-a 
concentrations. Scale units are in centimeters, degrees Celcius, and milligrams per cubic meter for 
SSHA, SST, and chl-a data, respectively. 
west monsoon (November-April; NW) for all years ex- 
cept 1999 (Fig. 2C). High HRs (average 0.55 HR) were 
recorded during the southeast monsoon, and lower 
HR (average 0.45 HR) occurred during the northwest 
monsoon. 
Features of oceanographic conditions 
The following results are presented to show how the 
different phases of ENSO affected oceanographic condi- 
tions in the EIO off Java. Figure 3 shows 6 snapshots 
of SSHA, SST, and chlorophyli-a conditions, each show- 
ing the means of values from 3 different months dur- 
ing different phases of El Nino (mean of September, 
October, and November 1997) and La Nina (mean of 
February, March, and April 1999) in the EIO off Java. 
The months that represent the El Nino and La Nina 
events were chosen on the basis of the 3 consecutive 
months with the highest individual values in the Nino 
3.4 index during El Nino and La Nina during 1997- 
2000. There were contrasting conditions of SSHA and 
SST along the coasts and in offshore areas during the 
El Nino and La Nina events. 
During the El Nino event, SSHA showed negative 
values (from -1 to -20 cm) along coastal regions of the 
EIO off Java (Fig. 3A). In contrast, offshore regions in- 
fluenced by frontal areas between 10-12°S and 15°S 
exhibited positive SSHA (4 cm). Lower SST (24-27°C) 
occurred in the coastal to offshore regions of the EIO 
off Java (Fig. 3B), and warmer waters (29°C) appeared 
in the eastern part of the EIO off Java. Conversely, 
during the La Nina event, positive SSHA (1-13 cm) 
occurred along the coasts, and negative SSHA (—5 to 
-3 cm) were found offshore between 12° and 16°S (Fig. 
3D). SST during the La Nina event both near the coasts 
and in offshore areas of the EIO off Java (27-29°C) 
were higher than values during the El Nino event in 
this region (Fig. 3E). 
Chlorophyll-a concentrations were higher during 
the El Nino event (0. 2-2.0 mg nr 3 ; mean of September, 
October, and November 1997; Fig. 30 than they were 
during the La Nina event (0.05-0.10 mg nr 3 ; mean of 
February, March, and April 1999; Fig. 3F). The highest 
concentration of 2 mg m -3 was detected during the El 
Nino event along the coast of the EIO off Java, and 
values decreased toward offshore (0.01-0.20 mg nr 3 ) 
around the frontal area at 10-12°S (Fig. 30. This vari- 
ation in chlorophyll-a values coincides well with the 
occurrence of lower SST in the same areas during the 
El Nino event (Fig. 3B). 
