sources and oil refineries and the synergistic impacts of
anthropogenic disturbance.
Fishing is a major activity, and at present in the 3,651
fishing villages situated along the 8,129 km coastline of
India, about one million are occupied in full time marine
capture fisheries. The value of the annual marine fish production of 4.6 m t during the year 2002–2003 and the
value of marine products export were US $152.92 m. This
is mainly due to the introduction of bottom trawlers, into
Indian waters in the early 1960s. Several types of net fishing have also been responsible for the over-exploitation of
marine resource. Along with increase in the targeted catch,
a number of untargeted fish and other biota are removed
from their habitat and discarded as waste (trash fish).
Shrimp trawlers probably have the highest rate of by catch
bringing in up to 90% more of “trash fish”. A total of 1,006
purse seines in India employed for fishing may have the
same effect on the seabed as that of the trawl netting. Random capture techniques employed in India destroy immature fish and other non-targeted marine species. Gill nets
used to catch fish bring in a host of other animals such
as dolphins, turtles, etc. Because of the large size of the
areas concerned (Gulf of Mannar and Andaman and
Nicobar Islands or other areas in India), and the general
lack of resources for enforcement, awareness education
appears to be more successful than legislation in controlling these activities.
Although now illegal, blast fishing has been
a widespread fishing technique in India. Schooling reef
fishes are located visually, after which the capture boat
moves within close range and a lighted bomb is thrown
into the middle of the school. Due to blasting, branching,
tabulate and foliose hard corals are shattered while massive and columnar corals are often fractured. Bombs made
of chemical fertilizers such as ammonium/potassium
nitrate were confiscated from the foreign poachers
apprehended in Andaman and Nicobar Islands. Gelatin
sticks were observed to be used to blast fish by the fishermen around Gulf of Mannar reefs (Venkataraman et al.,
2003).
Sedimentation throughout the coast of India physically
interferes with the recruitment of coral larvae, which
require a solid substratum upon which to settle and metamorphose. Illegal sand mining in Andaman Islands and
illegal coral quarrying in Gulf of Mannar (Tuticorin group
of Islands) and some islands of Gulf of Kachchh have
caused a lot of sedimentation and siltation on coral reefs.
There has been unprecedented bleaching of hard and
soft corals throughout the coral reefs of the world from
mid 1997 to late 1998 (Wilkinson, 1998, 2000). Most of
the corals in the coral reefs of India have been adversely
affected during the bleaching in 1998, which destroyed
most shallow water corals. This event has greatly reduced
live coral cover in the reef (Venkataraman, 2000). Study
conducted after or during the bleaching event reported
a reduction in live cover of corals in Gulf of Kachchh
(20–40%), Gulf of Mannar (20–40%), Lakshadweep
(20–30%) and Andaman and Nicobar Islands (<10%).
The live coral cover in Andaman and Nicobar Islands
was between 50–75%, which is very high when compared
to other reefs in the Indo-Pacific region (Muley et al.,
2000, Rajasurya et al., 2002).
In addition to natural and human induced coral degradation, coral diseases are considered to be one of the major
problems faced by the coral reefs in recent years. Necrotic
lesions, fleshy algal over-growth, black band disease, and
white band disease have been reported from the Andaman
and Nicobar and Lakshadweep Islands. In addition, a new
disease called pink line disease has also been reported
recently from Lakshadweep (Ravindran and Raghukumar,
2006).
The coral eating starfish, Acanthaster planci was the
focus in the late 1980’s and early 1990’s in the Andaman
and Nicobar Islands as well as in other coral reef areas
of India (Venkataraman and Rajan, 1995). Although
sediment core data have indicated Acanthaster outbreaks
10,000 years ago, recent studies have shown a relationship
between nutrient input and recruitment success of the larvae. Studies on echinoderm reproduction have demonstrated that the success of the recruitment of their
planktonic larvae depends on phytoplankton availability
following spawning.
Coral damage from the Tsunami of 26th
December, 2004
The major damage to reefs is caused by storms, particularly tropical cyclones and by tsunami. These cause major
intermittent damage to reefs, particularly to those reefs
that rarely experience these storms. Due to a 1969
cyclone, a large area of coral was buried under sand in
the Rameswaram area of the Gulf of Mannar. Likewise,
the cyclone of December 1987 in the Bay of Bengal devastated the coral reefs of the Mahatma Gandhi Marine
National Park of Port Blair, Andaman that resulted in piles
of broken coral colonies scattered near the shore.
A very severe earthquake with a magnitude of 9.0 on
Richter scale struck northern Sumatra, Indonesia on 26th
December, 2004, and it was widely felt along the east
coast of India. In Tamil Nadu, people felt distinct tremors
in many parts of Chennai. The quake was also felt along
the Coromandel Coast up to some areas in Vizakapatinam.
The devastating tidal waves consequent to the earthquake
lashed several coastal districts of Tamil Nadu and
Puducherry as well as the archipelagos of the Andaman
and Nicobar Islands. The Nicobar Islands were most
severely hit given their proximity to the island of Sumatra
and the epicenter of the earthquake. It is reported that shallow water coral reefs in the Andaman Islands have been
exposed 2 m above the water mark (Figure 3) whereas
the Nicobar group are submerged 2.0 m below the water
mark (Venkataraman, 2006).
Conservation
India has 36 marine protected areas of which 20 are entirely
located in intertidal/subtidal or seawater-mangroves, coral
CORAL REEFS OF INDIA
273
anthropogenic disturbance.
Fishing is a major activity, and at present in the 3,651
fishing villages situated along the 8,129 km coastline of
India, about one million are occupied in full time marine
capture fisheries. The value of the annual marine fish production of 4.6 m t during the year 2002–2003 and the
value of marine products export were US $152.92 m. This
is mainly due to the introduction of bottom trawlers, into
Indian waters in the early 1960s. Several types of net fishing have also been responsible for the over-exploitation of
marine resource. Along with increase in the targeted catch,
a number of untargeted fish and other biota are removed
from their habitat and discarded as waste (trash fish).
Shrimp trawlers probably have the highest rate of by catch
bringing in up to 90% more of “trash fish”. A total of 1,006
purse seines in India employed for fishing may have the
same effect on the seabed as that of the trawl netting. Random capture techniques employed in India destroy immature fish and other non-targeted marine species. Gill nets
used to catch fish bring in a host of other animals such
as dolphins, turtles, etc. Because of the large size of the
areas concerned (Gulf of Mannar and Andaman and
Nicobar Islands or other areas in India), and the general
lack of resources for enforcement, awareness education
appears to be more successful than legislation in controlling these activities.
Although now illegal, blast fishing has been
a widespread fishing technique in India. Schooling reef
fishes are located visually, after which the capture boat
moves within close range and a lighted bomb is thrown
into the middle of the school. Due to blasting, branching,
tabulate and foliose hard corals are shattered while massive and columnar corals are often fractured. Bombs made
of chemical fertilizers such as ammonium/potassium
nitrate were confiscated from the foreign poachers
apprehended in Andaman and Nicobar Islands. Gelatin
sticks were observed to be used to blast fish by the fishermen around Gulf of Mannar reefs (Venkataraman et al.,
2003).
Sedimentation throughout the coast of India physically
interferes with the recruitment of coral larvae, which
require a solid substratum upon which to settle and metamorphose. Illegal sand mining in Andaman Islands and
illegal coral quarrying in Gulf of Mannar (Tuticorin group
of Islands) and some islands of Gulf of Kachchh have
caused a lot of sedimentation and siltation on coral reefs.
There has been unprecedented bleaching of hard and
soft corals throughout the coral reefs of the world from
mid 1997 to late 1998 (Wilkinson, 1998, 2000). Most of
the corals in the coral reefs of India have been adversely
affected during the bleaching in 1998, which destroyed
most shallow water corals. This event has greatly reduced
live coral cover in the reef (Venkataraman, 2000). Study
conducted after or during the bleaching event reported
a reduction in live cover of corals in Gulf of Kachchh
(20–40%), Gulf of Mannar (20–40%), Lakshadweep
(20–30%) and Andaman and Nicobar Islands (<10%).
The live coral cover in Andaman and Nicobar Islands
was between 50–75%, which is very high when compared
to other reefs in the Indo-Pacific region (Muley et al.,
2000, Rajasurya et al., 2002).
In addition to natural and human induced coral degradation, coral diseases are considered to be one of the major
problems faced by the coral reefs in recent years. Necrotic
lesions, fleshy algal over-growth, black band disease, and
white band disease have been reported from the Andaman
and Nicobar and Lakshadweep Islands. In addition, a new
disease called pink line disease has also been reported
recently from Lakshadweep (Ravindran and Raghukumar,
2006).
The coral eating starfish, Acanthaster planci was the
focus in the late 1980’s and early 1990’s in the Andaman
and Nicobar Islands as well as in other coral reef areas
of India (Venkataraman and Rajan, 1995). Although
sediment core data have indicated Acanthaster outbreaks
10,000 years ago, recent studies have shown a relationship
between nutrient input and recruitment success of the larvae. Studies on echinoderm reproduction have demonstrated that the success of the recruitment of their
planktonic larvae depends on phytoplankton availability
following spawning.
Coral damage from the Tsunami of 26th
December, 2004
The major damage to reefs is caused by storms, particularly tropical cyclones and by tsunami. These cause major
intermittent damage to reefs, particularly to those reefs
that rarely experience these storms. Due to a 1969
cyclone, a large area of coral was buried under sand in
the Rameswaram area of the Gulf of Mannar. Likewise,
the cyclone of December 1987 in the Bay of Bengal devastated the coral reefs of the Mahatma Gandhi Marine
National Park of Port Blair, Andaman that resulted in piles
of broken coral colonies scattered near the shore.
A very severe earthquake with a magnitude of 9.0 on
Richter scale struck northern Sumatra, Indonesia on 26th
December, 2004, and it was widely felt along the east
coast of India. In Tamil Nadu, people felt distinct tremors
in many parts of Chennai. The quake was also felt along
the Coromandel Coast up to some areas in Vizakapatinam.
The devastating tidal waves consequent to the earthquake
lashed several coastal districts of Tamil Nadu and
Puducherry as well as the archipelagos of the Andaman
and Nicobar Islands. The Nicobar Islands were most
severely hit given their proximity to the island of Sumatra
and the epicenter of the earthquake. It is reported that shallow water coral reefs in the Andaman Islands have been
exposed 2 m above the water mark (Figure 3) whereas
the Nicobar group are submerged 2.0 m below the water
mark (Venkataraman, 2006).
Conservation
India has 36 marine protected areas of which 20 are entirely
located in intertidal/subtidal or seawater-mangroves, coral
CORAL REEFS OF INDIA
273