Lakshadweep coral reefs

• Category: Marine and Oceanic Biomes.
• Geographic Location: Indian Ocean.
• Summary: This archipelago of coral islands, atolls, and reefs is home to diverse marine life, but under considerable anthropogenic and climate pressure.

The Lakshadweep Coral Reefs biome is associated with the Lakshadweep Islands, formerly known as the Laccadive Islands. This Indian Ocean archipelago consists of thirty-six small coral islands along with twelve coral atolls, three coral reefs, and a handful of submerged banks. The entire group lies some 186 miles (300 kilometers) off the west coast of the state of Kerala in southern India, separated from the mainland by the Lakshadweep Sea. They comprise the smallest union territory of the Republic of India.

The Lakshadweep islands and atolls are formed wholly from coral; together with the nearby Maldives and the Chagos Archipelago, the islands form a terrestrial ecoregion. The coral reefs themselves have formed over thousands of years and are regarded as the richest corals in India. There are some 100 species of coral here, with the branched staghorn and the ridged brain coral being among the most remarkable.

The combined lagoon area of Lakshadweep is about 1,620 square miles (4,200 square kilometers); most is relatively shallow and largely separated from the open sea. The immediate territorial extent of the oceanic waters surrounding the archipelago is on the order of 7,700 square miles (20,000 square kilometers).

Biodiversity

Many marine species live around the Lakshadweep Archipelago, including a wide range of fish; approximately 600 species have been identified here. These species include butterflyfish, clownfish, parrotfish, lagoon triggerfish, and moray eels. Ink-blue starfish, sharks, dolphins, tuna, wahoo, and swordfish also live nearby. There are some ninety species of sponge and at least seventy species of echinoderms (starfish, sea urchins, sea cucumbers, and sand dollars).

The land is also important for significant numbers of sea turtles, which lay their eggs on the beaches, and for hermit crabs, which come ashore periodically. These beaches are vital in particular for the egg-laying functions of the leatherback, olive ridley, hawksbill, and green sea turtles, which face significant human-caused threats. Bird life, some of which feeds on these beach-bound species or their eggs, includes pelagic birds such as the brown noddy (Anous stolidus), the greater crested tern (Thalasseus bergii), and the lesser crested tern (Sterna bengalensis).

Plant life on the combined 12 square miles (32 square kilometers) of land surface is rather sparse. Among the chief intertidal-zone flora is ribbon seagrass (Cymodocea rotundata), a beach grass well adapted to both mud and dry-sand environments. Stands of stunted palms crowd some islets. Undersea vegetation includes seagrass, primarily Cymodocea rotundata, as well as five other species. Various forms of algae are also found in the waters near the coral reef, and well over 100 species of seaweed thrive around the reefs and further offshore.

Human Settlement

Together, the Androth, Kavaratti, and Minicoy Islands make up about half the population of the entire archipelago—Androth (11,100 people), Kavaratti (17,100 people), and Minicoy (10,700 people). The other people living in the area hail from seven other islands: Amini, Agatti, Kadmat, Kalpeni, Kiltan, Chetlat, and Bitra. The remaining twenty-six islands, islets, and atolls are uninhabited.

Most of the local people on the islands are related to those in the Maldives. They have traditionally lived by subsistence fishing. On larger islands there has also been extensive cultivation of coconuts, as well as bananas, vegetables, and edible root crops. As the population has grown, human activity has started to impinge on wildlife, with commercial tuna fishing beginning to cause problems, as some skipjack tuna are sought for sale to markets in Japan, Hong Kong, and elsewhere. Because the islands lack cold storage facilities, however, the rate of fishing for export is lower than in many other areas of the world. A canning factory that primarily processes yellowfin tuna has been operational since 1969 and the government has announced its goal of constructing cold storage facilities for island fishing operations.

The reefs and atolls have become a popular tourist destination, attracting both swimmers and divers since the area was opened in 1974. This has both positive aspects—wider publicity for ecological conservation, better income for Indigenous people—and negative ones, such as increased litter, fuel spills, and other wastes injected into the environment, and the potential for direct physical damage to the coral.

Environmental Threats

There has been an increase in pollution resulting from the dumping of rubbish in marine areas, and from refuse leaching through from burial pits. This problem is accentuated by the sandy, porous soil, which has led to the contamination of some groundwater and the spread of waterborne diseases.

Problems have also arisen from the increase in tourism, although this has been checked by limiting the number of tourists and restricting diving, motorboating, surfing, and some other water sports. In addition, to help reduce the effect on the environment, low-temperature desalination plants were opened on the islands of Kavaratti, Agati, and Minicoy—some of the first such plants in the world. In the 2020s, additional plants were planned for the islands of Amini, Androth, Chetlet, Kadmat, Kalpeni, and Kiltan.

The major threat to the coral reefs comes from climate change. The weather has always affected the region. Indeed, parts of Kalpeni Island were formed in 1847 after a storm dumped large amounts of coral on the beaches, raising the banks on the eastern and southern shores of the island. Climate change has led to seawater temperature warming, which set the scene for coral bleaching, including a particularly severe event in 1998 that affected roughly half of all live coral here; especially hard-hit were table coral, genus Acropora; and brush coral, genus Pocillopora. Major bleaching events occurred in 2010, 2016, and from 2023 to 2024, in which approximately 85 percent of the coral experienced bleaching. Ocean temperature increases are significantly higher than the global average in the Arabian Sea, and the region experiences more marine heatwaves than other regions, resulting in more coral bleaching events in Lakshadweep. The frequency of these events is concerning because corals need three to five years to recover. Ocean acidification is another factor that is causing more coral bleaching. Coral mining, or cutting off chunks of coral, is another concern. Local people often use coral as a cement substitute for housing construction and repair and many of the islands use coral to build roads and seawalls. Further, the examination of coral in 2024 indicated the Western Indian Ocean had experienced increased lead pollution. Leaded petrol pollution between 1990 and 2013 caused lead measurements in the region to double. Despite efforts to eliminate the source of this pollution, researchers who examined coral in late 2024 found evidence that the lead concentration had increased.

The overall rise in water levels will affect all the Lakshadweep Islands, causing problems for turtles, crabs, and other forms of life in the water and on the shrinking land areas. None of the islands rises much higher than 3 to 6 feet (1 to 2 meters) above the sea now.

The government of India has, for purposes of conservation administration, classified the Lakshadweep Coral Reefs biome as a wetland; this brings it under the jurisdiction of the National Wetland Conservation and Management Programme of its Ministry of Environment and Forests. There is a bird sanctuary, Pakshi Pitti, in the form of a protected sandbank of some 3 acres (1.21 hectares).

Bibliography

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