354
300
"E 250
o
o
~200
o
'I' 150
E
0.-100
o
z
50
K. K. C. NAIR, P. G. JACOB, and S. KUMARAN:
Fig. 8. Day and night variations in the distribution of pelagic amphipods under 1 m 2 (200-0 m) in
each 10° zone of longitude for the period April 16-0ctober 15 (solid line: day, dotted line: night)
Latitudinal vanatlOn (Figs. 6 and 7) shows a general decrease in numbers of
amphipods from north to south in both seasons reaching a minimum in the belt from
30° to 40° S. Likewise, the number of families and species also decreases from north to
south. The highest peaks for both seasons occur along the belt between 20° and 30° N,
due to the high values found in the northern part of the Arabian Sea and the Bay of
Bengal. In general, night values were much higher compared to day except in areas
within 20-30 0 N and 0-10
0
S (Fig. 7). The high day values for the former area were
300
E250
o
o
N
c!:,200
N
I
E 150
:;-100
z
50
Fig. 9. Day and night variations in the distribution of pelagic amphipods under 1 m 2 (200-0 m) in
each 10° zone of longitude for the period October 16 - April 15 (solid line: day, dotted line: night)