Status of Coral Reefs of the World 2000

Status of Coral Reefs of the World: 2000
Chagos
Although there is no significant large-scale human damage to the reefs, there is illegal
fishing around some reef areas, including the collection of sea cucumbers and shark.
Occasionally poachers have been apprehended and vessels and equipment confiscated.
India
The Gulf of Mannar is one of the most heavily stressed coral reef regions in India, with
impacts from destructive fishing, pollution and coral mining. Along the 140km coastline,
there are 47 fishing villages with a combined population of approximately 50,000. There is
severe over-exploitation of seaweeds, sacred chanks, pipefishes, sea horses and sea
cucumber, and the extensive use of bamboo fish traps has seriously depleted fish stocks.
Populations of pearl oysters, gorgonians and acorn worms (Ptychodera flauva) are also
severely depleted due to over-harvesting. Approximately 1000 turtles are harvested
annually and dugongs are also hunted. Increasing demand for grouper, snappers and
emperors will put further pressures on these populations, and blast fishing has also been
reported. Local fishermen complain that fish catches have declined both in the nearshore
and offshore coral banks and islands. Sand mining, extraction of trochus shells, damage by
crown-of-thorns starfish and sedimentation degrade corals in the area. About 250m 3 of
coral is quarried per day from the Gulf of Mannar region. The islands in Tuticorin have been
affected by industrial pollution and aquaculture. On the Keelakarai coast, sewage pollution
has resulted in the overgrowth of corals by mats of green algae. Black and white band coral
diseases have also been observed.
In the Andaman and Nicobar Islands deforestation has resulted in increased sediment
flows to the nearshore reefs, however there are no quantitative assessments of the rate of
sedimentation, nor the impacts on the reefs. Reports have indicated that corals have been
killed by large quantities of sediment laden fresh water, as well as overgrowth by fleshy
algae. Industrial pollution is also impacting the coral reefs around Port Blair. In
Lakshadweep Islands crown-of-thorns starfish were first noticed at Agatti Island in 1977
and have spread to most islands and reefs causing loss of corals. Black and white band
diseases and pink band disease have been observed in shallow coral areas, but bleaching
has been the main cause of loss in reef biodiversity. There is some coral mining, dredging
of navigational channels, unsustainable fishing practices, coastal development, and
souvenir collection. Recently, blasting of corals to create navigational channels has been
stopped, however, the construction of breakwaters on some islands is increasing coastal
erosion. No sewage or oil pollution has been reported on these reefs. People have
reported decreases in fish catches within the reef lagoons, which could be due to the loss
of live corals after the bleaching event, or to increased harvesting due to population
pressures (the population has tripled in the last 20 years). The methods used to catch live
bait for tuna fishing cause damage to the reefs and reductions in live bait stocks have
impacted on the local economy since the tuna fishery is the major industry in the islands. In
the Gulf of Kutch major impacts on the reefs are associated with industrial development,
ports and offshore moorings, pollution from large cities, and removal of mangroves. It is
estimated that human activities have reduced the coral cover by more than 50% on most
reefs here.
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