Contents Introduction I. Annual and Semiannual Variations I.1. The Northern Tropical Indian Ocean I.1.1. The Somali Current I.1.2. The Arabian Sea I.1.3. The Bay of Bengal I.2 The Indonesian throughflow I.2.1. Geography of the throughflow I.2.2. The Driving Force I.2.3. Volume Transports I.2.4. The Zonal Jet I.3. The Equatorial Indian Ocean I.3.1. Equatorial Currents I.3.2. Equatorial Waves I.4 The South Indian Ocean I.4.1. The South Equatorial Current I.4.2. The East African Coastal Current I.4.3. The Mozambique Channel and the Agulhas current II. Interannual variability and ENSO-related anomalies II.1. The Southern Oscillation and the QBO II.2. El Niño in the Indian Ocean II.3. Monsoon and ENSO III. Applications References

III. Applications

The Indian Ocean appears to be the theatre of many oceanographically interesting and unique features. This motivates oceanographers to study such phenomena in order to better understand the ocean itself. However, there are also socio-economical interests which might motivate our work as well.

Most of the countries sharing their coasts with the Indian Ocean are developing countries, except for Australia, South Africa, La Reunion Island and some countries of the Arabian peninsula. These countries live for a great part on their fisheries. Some others also on tourism such as the Maldives, the Seychelles, Mauritius...

These countries are very sensitive to climate variations which affect their fisheries and their tourism. Rainfall prediction over Indian was one of the first motivation which lead Sir Walker to study the relationship between the monsoon and ENSO. While it doesn't seem so obvious to find prediction skills through the study of the monsoon/ENSO coupling, available results are today, sufficient to analyse climatic conditions and to integrate this information in socio-economical sectors. This is the goal of international programmes such as the CLIPS (Climate Information and Prediction Services) project of the WMO (World Meteorological Organisation) or the regional programmes of the Intergovernmental Oceanographic Commission (IOC) .Such programmes could help various sectors to benefically use scientific results for a sustainable approach of their socio-economic activities.

III.1. Fisheries links to Fisheries

For Small Island States, or for coastal countries, fisheries is often the first or second most important income and a major contribution to the GDP. Therefore, the vulnerability of this sector to climate should be monitored and studied in order to prevent any combined environmental-human drastic effects on the fish stocks, and ultimately on the economy of those countries.

III.1.1. El Niño and Fisheries in the Indian Ocean

Although the effects of environmental variability on fisheries are increasingly recognised and identified, further research is still needed to precisely determine the functionnal relationships between hydro-climatic parameters and fish behaviour. Marsac and Le Blanc (1996) have shown some effects of interannual variability on industrial catches of yellowfin tuna that can be linked to the El-Niño/Southern Oscillation (ENSO) effects in the Indian Ocean. Such research could be developped for other species and if generalized, could greatly contribute to the protection of fish stocks and of the communities living on them.

III.1.2. Climate Change and Fisheries

The impact of climate change on fisheries is even less known than the the influence of interannual variability. Though global climate changes are identified with a diminishing uncertainty (global warming, sea level rise, etc.), regional and local changes in the climate system are not yet fully predictable. Therefore, most of one can be said on the vulnerability of fisheries towards climate change effects, is still on a speculative ground and no quantification of sensitivity can be estimated.

Anyhow, todays state of knowledge may be extrapolated in order to prevent from possible outcomes and precautions may already be taken by authorities and governments. This is the aim of the Intergovernmental Pannel for Climate Change (IPCC) through the United Nations Framework Convention for Climate Change (UNFCCC).

(i) The case of the Seychelles

Climate Change and the Fisheries in the Seychelles: this is a contribution to enable the Seychelles National Climate Change Comittee to prepare its first National Communication to the UNFCCC.

III.2. Coastal Zone Management

Please go to the Integrated Coastal Area Management (ICAM) website to learn more about this matter.
You will also find many useful links.