International Journal of Marine Science 2016, Vol.6, No.58, 1-8
6
Table 1 Seasonal density of zooplankton (ind./m
3
) in Shatt Al-Arab River.
Station 3 (Al-Faw)
The density of zooplankton ranged from 3797 ind./m
3
in autumn to 69223 ind./m
3
in winter (Table 1). The average
seasonal density was 31801 ind./m
3
.
The Copepoda was the dominant group which constitute 82% of the total zooplankton, the highest peak 68963
ind./m
3
in winter. The second important group was Zoea of crabs (10%) then Rotifera (6%) (Fig. 8).
Discussion
Zooplankton plays a very important role in the food chain, they are in the second trophic level as primary
consumer and also as contributors to the next trophic level its constitute important food item of many omnivorous
and carnivorous fishes (Dewan et al., 1977).
The densities of zooplankton and volume specific biomass are usually greater in the estuaries than in other aquatic
habitats, reflecting the generally higher productivity of the estuarine environment. So in the present study the
Total
Autumn
Summer
Spring
Winter
Zooplankton
Al-
Faw
Abu Al-
Khasib
Al-
Ashar
Al-
Faw
Abu Al-
Khasib
Al-
Ashar
Al-
Faw
Abu Al-
Khasib
Al-
Ashar
Al-
Faw
Abu Al-
Khasib
Al-
Ashar
46661
941
494
742
-
666
96961
-
1911
.1.9
.17
111
-
Moina affinis
.0.6
-
-
-
-
-
-
-
-
-
-
-
.1.2
Simocephalus
(
Simocephalus
)
vetuloides
60.6
-
91
7119
-
967
1261
-
46
-
-
916
-
Diaphanosoma
brachyurum
0.04
-
-
-
-
-
-
-
-
-
-
-
.1.4
Daphnia
hyalina
0.41
-
-
-
-
-
-
-
-
-
-
-
.149
Chydorus
sphaericus
sphaericus
23481
411
134
3.60
0
040
40144
.
6603
.0.4
.04
101
.0.4
Total of
Cladocera
40905
796
911
-
9119.
91.
971
1191
1911
91.4
92999
.1.1
116
Calanoida
4378
9116
46
-
-
2.19
16..
14
617
-
9.7
641
Cyclopoida
1316
7.1
72
416
227
-
-
-
717
9416
-
9119
.1.9
Harpactecoida
59564
6..
-
.17
6...
11.
6716
466
191
-
69167
-
.149
Nauplii
106163
932.5
73.3
4.7
26082
570
255.7
7869
720.3
20.84
68963
115.13
557.02
Total of
Copepoda
36904
926
1711
141
119
77711
4116
9624
7.16
9217
-
41
9.9
Cirriped larvae
8424
7461
72
-
91.
.16
4466
14.
719
761
1.
.1.1
Rotifera
0.02
-
-
-
-
-
-
-
.1.9
-
-
.1.9
Insecta larvae
351
-
-
-
119
-
716
-
91
-
-
.1.1
.1.9
Fish larvae
548
9116
1
-
11
9216
466
9114
91.4
-
-
-
Ostracoda
12731
-
9419
1
976..
17
7.19
-
416
91.4
-
-
-
Zoea of Crab
0.03
-
-
.1.7
-
-
-
-
.1.9
-
-
-
Amphipoda
16.4
-
-
-
9112
.1.1
716
-
-
-
.17
-
-
Shrimp larvae
41.9
-
-
-
4914
-
-
-
-
-
.16
-
-
Mycedacea
290
-
-
-
71.
-
-
-
-
-
-
-
-
Saggeta
54.9
9116
-
-
4914
-
-
-
-
-
-
-
-
Mollusca
54.2
64
-
-
.17
-
-
-
-
-
-
-
-
Medosa
189060
3616
3611
313.
31634
43104
436.6
411..
30.0
4046
61443
4.3
6.1
Total of
zooplankton
