Abstract

The Gulf of Mannar consists of ecologically sensitive important habitats such as: coral reef and seagrass. Though each has its own function and importance, two are closely interrelated and supporting each others in function. The majority of the reefs are formed around the 21 islands, while vast sea grass beds are seen in the shoreward side of each islands. In most cases the sea grasses bordering the coral reefs play important role in limiting sedimentation on the coral reefs and help in protection. The coral reefs help in controlling erosion of islands and thereby protecting destruction. These habitats are highly productive and so economically important. The physical, chemical and biological data collected from Manoli Island of Mandapam group of the Gulf of Mannar clearly reveal the interrelationship in enhancing the associated resources, particularly fishes and other invertebrates due to constant supply of nutrients and other favourable environmental factors. The ‘transient’ coral and seagrass associated fishes use these habitats for shelter, food and breeding. During windy and turbulent period in the Gulf of Mannar (April to August), the water is highly turbid and most dense seagrass beds are disturbed because of strong wave action and this period the nearby reefs act as major shelter point to the associated fish resources of seagrass areas. The ecological and economical use of these two important habitats stresses the need for their proper conservation and management to sustain the benefits.

Key words: Gulf of Mannar, interrelation among coral reef and sea-grass habitats, physical, chemical and biological data.