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Fig. 1—Vaan Island before splitting during May 2010  
Fig. 2—Vaan Island after splitting during May 2013  
Fig. 3—The channel which divided Vaan Island  
Fig. 4—Remnant part of Vaan Island during October 2014  
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Indian Journal of Geo-Marine Sciences
Vol. 44(6), June 2015, pp. 892-895
Research news article
Vaan Island of Gulf of Mannar, Southeast coast of India - on the verge of
submergence
*K. Diraviya Raj1, G. Mathews2 & J.K. Patterson Edward3
Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin-628 001. Tamilnadu, India
*[E-mail: diraviyam_raj@yahoo.co.in]
Received 05 February 2014; revised 11 September 2014
Vaan Island of Tuticorin region is one of the 21 uninhabited islands of Gulf of Mannar, Southeast coast of India. It has
been stated invariably in all reports and articles that this Island has 16 hectares land as per its 1986 status. But, presently
Vaan Island has only about 2.5 hectares of land left because of severe erosion. Since 2013, erosion has been very severe as
the Island was split into two parts and one part is completely under the water now. Primarily coral mining coupled with sea
level rise are the reasons behind the erosion. Considering the rate of erosion, Vaan Island is expected to totally submerge
soon, if no immediate intervention is made.
[Keywords: Vaan Island, Gulf of Mannar, coral mining, currents, sea level rise]
Introduction
Low-lying reef islands and their population
are considered physically vulnerable to a range of
climate change impacts, especially to sea level rise1.
Most anticipated physical impacts of sea-level rise on
islands are shoreline erosion, inundation, flooding,
salinity intrusion, and reduced resilience of coastal
ecosystems2,3. The future persistence of low-lying reef
islands has been the subject of considerable
international concern and scientific debate4. Gulf of
Mannar located in the southeast coast of India extends
from Rameswaram Island in the north to
Kanyakumari in the south. It has a chain of 21
uninhabited coral islands stretching from
Rameswaram to Tuticorin covering a coastal distance
of 140 km. The Government of Tamilnadu in 1986
declared the 21 islands and surrounding shallow
coastal waters as Gulf of Mananr Marine National
Park for the purpose of protecting marine wildlife and
its environment. Vaan Island is the first of the 21
islands from Tuticorin and nearby coastal area is
thickly populated. Corals and associated fishery
resources around the Island have been heavily
exploited through coral mining and destructive fishing
practices. There is a pillar near Vaan Island which is
approximately 300 m away from the Island and rooted
in the sea now. As per the records, this pillar was built
at the southeast corner of the Island land5. Vaan Island
was originally 16 hectares in size as per the
Government Notification on its Marine National Park
Status in 19866. The current status of Vaan Island in
terms of size and the impact of natural and human-
induced stressors are discussed below.
Present scenario
Measurement of the Island was done initially
during May 2013 and then during October 2014 to get
the current size of the Island. The formations of reef
platforms of pleistocene and modern reef are reported
in the Gulf of Mannar along the periphery of the 21
uninhabited islands between Tuticorin and
Rameshwaram5. Vaan Island is formed by the
complex physical and biological process started from
the interglacial period to present day and the elevation
of the Island varies from 0.5 to 1.5m above mean sea
level7. It is observed in the present study that the
Island had only 5.7 hectare area during May 2013 in
contrast to the previous record of 16 hectares in 1986.
Furthermore, it was noticed that Vaan Island had been
split in to two (southern and northern parts) as sea
water entered through a narrow channel from one side
of the Island to the other during high tides. On the
south side it was 2.7 hectares and on the north side it
was 3 hectares. The gap between the two parts was
RAJ et al.: VAAN ISLAND OF GULF OF MANNAR….ON THE VERGE OF SUBMERGENCE
893
about 40 m in length and 15 m in width during the
low tide in May 2013. This gap kept on increasing
and eventually divided the Island in to two parts
permanently. Erosion on the northern part of the
Island was very severe and it submerged underwater
in no time. During October 2014, total area of the
remaining Island was about 2.5 hectares only (Figs. 1
to 4). However, invariably in all publications, the area
is referred as 16 hectares (eg. Ravindran 2012,
Monishiya & Padmanaban 2012)7,8.
The erosion in Vaan Island could be mainly
because of a combination of several natural and
human induced factors. Mining of corals around the
Island for several decades degraded the Island area
and also made the substratum unstable and the island
shores became vulnerable to strong currents, waves
and tidal action. Corals act as a physical barrier
against strong waves and currents and protect the
shore from erosion. In Gulf of Mannar, especially in
Vaan Island, corals were mined for building,
industrial and chemical purposes which destabilized
the foundation of the Island. It was estimated that the
exploitation of corals was about 60,000 cubic meters
per annum from Palk Bay and Gulf of Mannar
together9. The rapid development of lime based
industries in and around Tuticorin had accelerated the
coral reef exploitation5. Two of the 21 Islands of Gulf
of Mannar (Vilanguchalli Island in Tuticorin group
and Poovarasanpatti Island in Keelakarai group) have
already submerged. Coral mining reduces the function
of reefs as natural barriers and lead to increased beach
erosion10,11, and was probably responsible for the
submersion of two islands12.
Fig. 1—Vaan Island before splitting during May 2010
Fig. 2—Vaan Island after splitting during May 2013
Fig. 3—The channel which divided Vaan Island
Fig. 4—Remnant part of Vaan Island during October 2014
INDIAN J. MAR. SCI., VOL. 44, NO. 6 JUNE 2015
894
Coral mining was completely stopped in Gulf
of Mannar from 2005 because of the combined effects
of strict enforcement and awareness among the
fishermen13. Indian Ocean Tsunami in 2004 caused
little damage to the live corals of the Gulf of Mannar14
and after tsunami, it was reported that live coral cover
in Vaan Island was 33.13%15. Since then, it has been
reported many times that live coral cover in Tuticorin
group of islands has increased considerably13,16.
However, despite this increase in coral cover, erosion
has been severe in Vaan Island because of the
consequence of earlier rampant mining activities for
about 5 decades. Besides mining, destructive fishing
practices like near-shore trawling, shore seine and
push net operation, sedimentation and pollution are
also causing considerable damage to the coral reefs,
threatening the key habitat and associated fisheries of
the Gulf of Mannar17. Including corals, all the
resources are damaged by bottom trawling which
indiscriminately smashes everything on their way and
cause irreversible, extensive and long lasting physical
and biological damages18. Coral-algal phase shift has
also been reported in Gulf of Mannar19 which is a sign
of a degraded reef. The impact of climate change is
also to be considered seriously. Changes in the
climate system are predominantly revealed in ocean
temperatures and the associated thermal expansion
contribution to sea-level rise35. Mean global rate of
sea-level (RSL) rise has been estimated at 1.8 mm/yr
for the last century36 and is expected to rise further.
Sea level rise aggravated the erosion in Vaan Island
which is already exposed to strong waves and currents
due to the absence of natural barriers like coral reefs.
Thus it is expected that the shrinkage of the Island
would be fast leading to submergence.
Vaan Island is a symbol for Tuticorin and
also has been traditionally helpful to the local
fishermen. It also acts as a shelter to the fishermen
during rough seasons or during boat breakdown. It is
a natural barrier to nearby Siluvaipatti and Vellapatti
coastal villages from natural calamities. It provides
habitat to several terrestrial flora and fauna which
would eventually die if the Island perishes.
Considering the present rate of erosion, the Island
would go under the water soon if there is no
immediate intervention. Focused coral rehabilitation
in a phased manner in the degraded reef areas of Vaan
Island and deployment of artificial reefs parallel to
island shore after conducting studies like wave
dynamics pattern would not only help to save the
island from sinking, but also would enhance live coral
cover and fishery production for sustained livelihood
to artisanal fishermen.
Acknowledgement
Authors are thankful to Principal Chief
Conservator of Forests and Chief Wildlife Warden,
Government of Tamil Nadu and Wildlife Warden,
Gulf of Mannar Marine National Park for research
permissions; and SDMRI authorities for research
support.
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