4. Standing Stock and Distribution of Zooplankton
4.1
Zooplankton Studies in the Indian Ocean
T. S. S. RAo
There are a number of papers dealing with the distribution of different species and
groups of zooplankton from the coastal areas of the Indian Ocean, particularly adjacent
to India, Australia and South Africa. However, for many reasons these studies are not
comparable to the observations made on the present IIOE collections. Firstly, with a few
exceptions, the IIOE collections were taken from the open ocean and secondly they were
collected over a period of 6 years (1960-1965) from a wide area of the Indian Ocean.
Most of them were collected with the Indian Ocean Standard Net, IOSN (CURRIE, 1963)
Ship
1. "Novara"
2. "Challenger"
3. "Gazelle"
4. "Valdivia"
5. "Gauss"
6. "Seal ark"
7. "Planet"
8. "Mowe"
9. "Dana"
10. "Snellius"
11. "Discovery II"
12. "Mabahiss"
13. "William Screshy"
14. "Albatross"
15. "Charcot"
16. "Galathea"
17. "Umitaka Maru"
18. "Guilard"
Table 1. Indian Ocean Stations (prior to nOEl
Date
1857- 59
Dec. 1873 - Mar. 1874
1874---76
1898-99
1902-03
1905
1906-07
1912 -13
1928-30
1929
1930,32,35,38
1933-34
1935,36, 50
1947-48
1948-49
1950- 52
1956
1961
No. of Stations a
52
6
37
67
26
23
57
7
171
25
124
80
60
22
10
48
32
77
Total: 924
a The information under this column is not complete and does not include stations south of 45° S
latitude.
vertically from 200 m depth to the surface. Table 1 shows the work done before the
IIOE. Table 2 indicates the density of samples taken during the IIOE for 4 different
seasons. Tables 3 and 4 respectively give the seasonal coverage of selected areas and
areas of poor zooplankton sampling during the IIOE. Figs. 1- 3 illustrate the sampling
coverage by area and time.