Reefs in India



The Gulf of Kachchh reefs (22º15`-23º40`N; 68º20`-70º40`E) are the northernmost of India.

The coral growth occurs in the form of fringing reefs on the wave-cut sandstone banks around 32 islands among the 42 that adjoin the southern flank of the Gulf.

Because of the geographical isolation and the extreme environmental variations (temperature range 15-35ºC, salinity range 25-40), strong tidal currents and the heavy sediment load, the diversity of corals is quite low: 37 species under 23 genera. All coral species are massive or encrusting, with a total absence of arborescent and racemose forms.

Noteworthy associated ecosystems are the mangroves and algal beds. The mangroves occur in dense strands in most of the islands and as stunted patches along the coast.
The reefs were in healthy state until early 80s when industrial development became intensive along the southern coast. Dredging of coralline sands for cement industries and the impacts of onshore developmental activities were responsible for the reduction in the density of corals. Another cause for loss of coral cover is the extensive deforestation of the mangroves along the coast. The silts washed onto the corals has killed a large fraction of intertidal corals.

All the island reefs and the intertidal expanses with corals have been declared as Gulf of Kachchh Marine National Park.


The reefs of the Gulf of Mannar have been reasonably well-studied thanks to their proximity to Institutions like Central Marine Fisheries Research Institute, Central Salt and Marine Chemicals Research Institute, Madurai Kamaraj University and Center of Advanced Studies in Marine Biology. So far, a total of 91 species of corals under 35 genera have been recorded from these reefs. Other groups that have been studied extensively are marine algae, echinoderms, mollusks, sponges and polychaetes.

Very few of the 20 reefs are in reasonably good shape. The northern islands, especially Kurusadai and Shingle have been heavily impacted due to collections by college and university students over several decades. The southern ones near Tuticorin have been affected by industrial pollutants, especially fly ash and liquid effluents from onshore industries. Most other reefs have been extensively mined for coral blocks and debris. With the inclusion of all these reefs in the Gulf of Mannar Biosphere Reserve, mining has been almost stopped though clandestine removal is still a possibility.

The Gulf of Mannar reef formations are of fringing type, developed around 20 islands located in a chain between Tuticorin (8º48`N; 78º9`E) and Rameswaram (9º14`N; 79º14`E), on the SE coast of India. The reef around the Rameswaram Island extends into the Palk Bay as an 8 km long fringing reef along the mainland coast.


The Lakshadweep reefs (9-12ºN; 72-74ºE) are the only atolls in the Indian seas. This group comprises of 12 atolls, 3 reefs, 5 submerged banks and 36 islands.

The Lakshadweep atolls lie about 200 km offshore from the west coast of India.Bitra is the northernmost atoll and also has the smallest inhabited island in India on it. Minicoy atoll is the southernmost, separated from the rest by the 9º channels.

Biodiversity is relatively quite high in the Lakshadweep atolls. The current record for the Scleractinian corals is 104 species under 40 genera, which in all probability is a lower estimate, since collections were restricted so far only to shallow waters and few islands. Several other groups, however, have been well studied. For example, 603 species of fishes are known from the Lakshadweep reefs.

Noteworthy associated ecosystem is the sea grass bed in the lagoons of several atolls. Minicoy island has a small patch of mangroves at the southern end.
The islanders are seafarers and fishermen. The skipjack Katsuwonus pelamis is the tuna caught in abundance and marketed commercially. Fishing in the lagoons is mainly for sustenance. Tourism is a developing activity but carefully regulated so as not to exceed the carrying capacity of the islands.

About Rashid Faridi

I am Rashid Aziz Faridi ,Writer, Teacher and a Voracious Reader.
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