There are 4 major coral reef areas in India: Gulf of Mannar; Andaman and Nicobar Islands (1962km coastline); Lakshadweep Islands (132km coastline); and the Gulf of Kutch (Kachchh). There is also scattered coral growth on submerged banks along the east and west coasts of the mainland. Coral reefs are important economically for the livelihoods and social welfare of coastal communities providing up to 25% of the total fish catch.

Reefs in the Gulf of Mannar are found around a string of 21 islands, 8km off the southeast coast of India. The 3 island groups (Mandapam, Keelakari and Tuticorin) form the ‘Pamban to Tuticorin barrier reef’, which contains fringing, platform, patch and barrier reefs. Narrow fringing reefs surround the islands extending 100m from the shore. Patch reefs are also found and are typically 1-2km long, 50m wide and 2 to 9m deep. Reef flats are extensive on all islands. The total area includes approximately 65kmsup2; of reef flat and 14kmsup2; of algal growth. The major economic activities are fishing, coral mining for construction, harvesting of sacred chanks (Turbinella pyrum), sea cucumber, pipefishes, sea horses and seaweeds.

Of the 530 islands in the Andaman and Nicobars, only 38 are inhabited with 279,000 people as of 1991, but this is predicted to rise to 405,000 in 2001. The largest islands of North Andaman, Middle Andaman, Ritchie’s Archipelago, South Andaman, Little Andaman, Baratang and Rutland Island are mountainous and forest covered, and are surrounded by some of the richest coral reefs in India.

The Lakshadweep Islands are true atolls at the northern end of the Laccadive-Chagos ridge, 225-450km west of the Kerala coast. There are 12 coral atolls with 36 islands and 5 submerged banks. Islands vary in size from 0.1km² to 4.8km² (total area 32km²) and are surrounded by 4,200km² of lagoon, raised reefs and banks. The population on the 10 inhabited islands ranges from 100 on Bitra Island to 10,000 on Kavaratti. Offshore fishing is the most important activity, and reef fisheries are not economically important. Tourism is slowly developing, but provides little income for the local community.

There are 42 islands with fringing reefs in the southern part of the Gulf of Kutch along with extensive mangroves in the Indus River Delta. Corals survive through extreme environmental conditions such as high temperature, salinity changes, high-suspended particulate loads and extreme tides, as high as 12m.

Coral reefs are found in 4 major areas. Two are adjacent to the mainland of India: Gulf of Mannar; and the Gulf of Kutch (Kachchh). The other two are the offshore island chains of the Andaman and Nicobars and Lakshadweep Islands. Fringing, platform, patch and barrier reefs occur around 21 islands (2 of which are submerged below 3m) along the 132km Gulf of Mannar coastline. Corals are also found along the mainland coast. One island in the Tuticorin group has disappeared below the surface due to coral mining. Most of the other reefs in the Tuticorn group are also mined, along with strong pressure from fisheries, including harvesting of sacred chanks (Turbinella pyrum), sea cucumber,
pipefishes, and sea horses. Seaweed harvesting occurs in some islands of the Mandapam group. Particularly rich reefs grow around the 530 mountainous islands in the Andaman and Nicobars, of which only 38 are inhabited. The Lakshadweep (Laccadive) Islands consist of 12 atolls, 36 islands and 5 submerged banks at the northern end of the Laccadive-Chagos ridge. The islands are surrounded by 4,200km2 of lagoon, raised reefs and banks and are the base for an important tuna fishery with minimal tourism. Coral and sand mining, erosion, coastal reclamation and crown-of-thorns starfish (Acanthaster planci) infestations affect the health of the reefs. In the Gulf of Kutch, 34 out of 42 islands have fringing reefs, but these have been severely damaged by sedimentation, industrial pollution, extraction of coral sand, fishing with poisons and explosives. As well there are stresses of high temperatures, salinity changes, turbid water and exposure during extreme low tides (range to 5.9m).

The total coral reef area in India is 5,790 km2, distributed between 4 major regions: Lakshadweep; Gulf of Mannar; Gulf of Kachchh; and Andaman and Nicobar Islands. Reef structure and species diversity vary considerably between the areas due to differences in size and environmental conditions.Lakshadweep is an archipelago of 12 atolls surrounded by deep water, on the northern end of the Laccadive-Chagos ridge. In the Gulf of Kachchh, there are shallow patchy reefs growing on sandstone platforms that surround 34 islands. The reefs experience high salinity, frequent emersion, high temperature fluctuations and heavy sedimentation. In the Gulf of Mannar, coral reefs are found mainly around 21 islands between Rameshwaram and Tuticorin. Two former islands are now submerged, probably due to coral mining and erosion. The Andaman and Nicobar Islands consist of 530 islands with extensive fringing reefs which are mostly in good condition. Corals have also been reported from Gaveshani Bank about 100 km offshore from Mangalore, and several areas along the eastern and western coast of mainland India, e.g. the Malvan Coral Reef Sanctuary near Mumbai.

Average live coral cover around the 21 islands in the Gulf of Mannar is 35%, a slight increase over the past 5 years. The highest coral cover occurs in the Keezhakkarai island group (44%) and the lowest in the Tuticorin Group (29%): 117 coral species were recorded in the area in 2005, including 13 new records. Habitat structures, in particular live corals, play a major role in enhancing fish diversity and 50 reef-associated fish species in 27 families were observed in 2005 (Figure 8.4).

Gujarat



The state of Gujarat has a 1650 km long coastline with a broad continental shelf: it contains 35% of India’s total shelf area, including 7350 km² of the shallow Gulf of Kachchh. The marine environment in the Gulf of Kachchh is extreme, with water temperatures varying between 15o and 30oC and high salinity in areas with high evaporation. The tidal range is very high and the waters are particularly turbid which limits coral reef development. Coral communities (total area, 460 km²) are found around 20 of the 42 islands, 20 islands have mangroves, while 6 ‘islands’ are submerged. Industrial development is intense in the Gulf, with 11 ports and 21 major salt industry sites producing >70% of India’s total salt production.