The Marine Ecosystem of Tuticorin Bay
Tamil Nadu has a coastline of 992 kilometers. This seaboard is touched by the Bay of Bengal, Palk Strait, Gulf of Mannar, and the Arabian Sea. The water supports the growth of several genera of octocorals and many other organisms known to produce bioactive compounds.
Soft corals of varied shapes and colors flourish along the Gulf of Mannar, presenting one of the most beautiful sights in the world, rivaling the most gorgeous flower gardens. Coral animals thrive best in warm, shallow, clear, well-lit and well-oxygenated waters, conditions that are found only in the tropical and sub-tropical regions of the world. The reef-building corals remain quite restricted in their distribution and can grow only where the water temperature never falls below 20 degrees Celsius. The coral formations of the southeast coast of India are mostly centered around the small islands in the Gulf of Mannar from Rameswaram to Tuticorin (Toothukudi), and along the shores of Rameswaram Island and Mandapam Peninsula in Palk Bay.
The coral reef of the Gulf of Mannar is a barrier also known as Mannar Barrier, which extends to a length of nearly 140 kilometers. The 20 small islands that stretch from Rameswaram to Tuticorin (Toothukudi) are typical sand cays that develop in the barrier. Barnacles and sponges are the most abundant representatives of the community in Karrapad Creek in Tuticorin Bay. Anemones, hydroids, polychaetes, bivalves and ascidians also constitute considerable portions of the community.
Bryozoans and serpulids reported to be abundant in other localities along the coast of India are not significant here. The poor representation of Bryozoans is probably due to heavy silt and high rates of sedimentation in the creek especially during rainy season, and the dense settlement of encrusting sponges. When sponges are abundant, they were found to inhibit the settlement of other major fouling animals by covering the substrata almost completely.
The common fouling organisms found in Tuticorin Bay are shown in the table below: