The effect of tsunami on sea turtle nesting beaches along the coast of India

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December 13-14, 2005, Siam City Hotel, Bangkok, Thailand

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Title
The effect of tsunami on sea turtle nesting beaches along the
coast of India
Author(s)MURUGAN, A.
Citation
Issue Date2005
URLhttp://hdl.handle.net/2433/44088
Right
TypeConference Paper
Textversionpublisher
KURENAI : Kyoto University Research Information Repository
Kyoto University

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The effect of tsunami on sea turtle nesting beaches along
the coast of India

A. MURUGAN
Suganthi Devadason Marine Research Institute
44-Beach Road, Tuticorin-628 001, Tamil Nadu, India
E-mail: muruganrsa@yahoo.co.in

ABSTRACT
The devastating earthquake off the west coast of Sumatra and the resultant tsunami on December 26th
2004 has left a marked impact on the Andaman and Nicobar Islands and also along the Indian
mainland coast especially along Tamil Nadu province. Transgression of shoreline occurred along
many parts of northern Tamil Nadu coast especially in sea turtle nesting beaches. However, turtle
nesting has been reported along these beaches after the tsunami event. Andaman and Nicobar
Islands are the worst affected in India. Shoreline alteration has occurred in many areas of Andaman
and Nicobar Islands. Among the Nicobar group of islands, decrease in the extent of sandy beach of
Camorta and Noncowry Islands has been reported. Trinkat Island has almost been split into three
pieces. Many turtle nesting beaches have been washed away in Nicobar group of Islands, but new
beach formation has occurred. The beaches have been reported as littered with debris, which will
certainly have an impact on nesting turtle population.

KEYWORDS: Andaman and Nicobar Islands, tsunami, sea turtle, Tamil Nadu, shoreline change,
nesting beach

INTRODUCTION
Olive ridley (Lepidochelys olivacea), green
(Chelonia mydas), hawksbill (Eretmochelys
imbricata), loggerhead (Caretta caretta) and
leatherback (Dermochelys coriacea) are the five
species of sea turtles distributed along the Indian
coast. With the exception of loggerhead all other
species have been reported to nest along the Indian
coast. Olive ridley is the most common and abundant
in India and is unique for its mass nesting along the
Orissa coast (Karthik Ram, 2000; Kar, 2001). Three
olive ridley mass nesting beaches, Gahirmatha, Devi
river mouth and Rushikulya are located in the Orissa
state on the northeastern coast of India.

NESTING BEACHES ALONG THE INDIAN
COAST
Sea turtle nesting has been reported along West
Bengal, Orissa, Andhra Pradesh, Tamil Nadu, Kerala,
Karnataka, Goa, Maharashtra, Gujarat and Andaman
and Nicobar Islands (Murugan, 2003). Tamil Nadu
and Andhra Pradesh coasts are considered the
migrating pathways of the olive ridleys migrating
towards the mass nesting beaches in Orissa. In Tamil
Nadu, the coastal stretch between Tranquebar and
Pazhayaru, Mamallapuram and Chennai, Point
Calimere and Nagapattinam and Kanyakumari and
Trichendur have been reported for turtle nesting in
Tamil Nadu (Kar and Satish Bhaskar, 1982; Bastian
Fernando, 1983).
Andaman group of islands comprise of about
306 islands (Figs 1 and 2). Nicobar group has 22
large and small islands (Ramachandran et al., 2005).
Humans inhabit twenty four islands of Andaman
group and 12 in Nicobar group. The entire Nicobar
group is a tribal reserve. All five species have been
reported along Andaman and Nicobar Islands
(Bhaskar and Rao, 1992; Andrews et al., 2001;
Andrews and Tripathy, 2004; Murugan, 2005). Great
Nicobar Island is unique in that all four species occur
along its southeast coast (Sivakumar, 2002).
Green turtle is the most common species in
Andaman and Nicobar Islands. Thirty seven green
turtle nesting sites have been reported in Andamans
including Little Andaman and 12 sites in Nicobar
group. The main nesting sites include the three
nesting sites on the east coast of Baratang Island in
Horsford, Rawlen’s and Grieve Bays, North of
Outram Island, Long and North Passage Islands and
Petri and Bluff Islands along West coast, Robert Bay
in Middle Andaman Islands and South Sentinel
Island (Andrews et al., 2001; Andrews and Tripathy,
2004; Murugan, 2005). Hawksbill turtles are
considered as the important population in the
northern Indian Ocean area and are the largest in
India.
Twenty three leatherback nesting sites have been
reported in Andaman and Nicobar islands. The most
important hawksbill turtle nesting beaches are South
Reef Island in middle Andaman, North Brother and
Snark Islands in the South Andaman. Overall, 27
hawksbill nesting sites in 26 islands have been
reported in Andaman group, three in Little Andaman
and 12 sites in Nicobar group. Nicobar Islands are

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Fig.1. Andaman group of Islands



























Fig.2. Nicobar Islands

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unique in that the nesting leatherback turtle
population is one among the four important colonies
in the Indo-Pacific region with more than 1000
individuals.
Olive ridley nests only on the east coast of
Andaman Islands with 12 sites and that of Nicobar
group with three sites. The main sites in Andaman
are Madhuban in South Andaman, Cuthbert Bay and
Karamatang in Middle Andaman, Ramnagar and
Coffeedera beaches in North Andaman; Smith,
Trilby and Hump Islands; three beaches on the West
coast of Little Andaman Islands. In Nicobar group,
the major nesting location is Great Nicobar with four
nesting beaches followed by Teressa Island.

INDIAN OCEAN TSUNAMI
AFFECTED TURTLE NESTING PLACES
The devastating earth quake of 9.3 (Ishii et al., 2005)
on the Richter scale and the resultant tsunami that
originated along the Sumatra coast, affected many
sea turtle nesting beaches along the Indian coast
especially the Andaman and Nicobar Islands. The
impact is less along the mainland coast when
compared to the Andaman and Nicobar Islands.
Kerala and Andhra Pradesh are the other affected
states with turtle nesting beaches. Tamil Nadu state is
the worst hit next to Andaman and Nicobar Islands.
Though coastline changes have occurred along the
northern Tamil Nadu coast, the turtle nesting beaches
have not suffered as much alteration as that in
Nicobar group of islands. Sporadic turtle nesting
have been reported along this stretch after the
tsunami. While damages to the coral reefs of Gulf of
Mannar were very minimal, the reefs of Andaman
and Nicobar Islands suffered extensive damage
(Alfred et al., 2006) owing to its proximity to the
Sumatra coast.
In Andaman and Nicobar Islands, the tsunami
impact was more along the Nicobar and South
Andaman Islands. Low lying areas from South
Andaman to Nicobar group of islands have
submerged by about 1 to 4 meters. The tidal and
subtidal areas in north Andaman Islands have been
uplifted (Sarang Kulkarni, 2005) by about 0.60-0.90
m (Alfred et al., 2006). The tsunami has also exposed
the western coast reef flats of Interview Island, North
Reef Island, Latouche Island, South Reef Island,
West Island, Landfall Island, East Island and
Anderson Island (Alfred et al., 2006). The Landfall,
West, Latouche and North Reef are the important
green turtle nesting areas (Andrews and Tripathy,
2004). Due to this the access of turtles to the beach is
restricted. The islands of North Button, Middle
Button, South Button, North Passage, Outram,
Havelock, Inglis and Neil Hugh Rose Islands, the
reported green and hawksbill nesting areas, along
Ritchie’s Archipelago suffered no major impact. The
tsunami devastated the northeastern side beach of the
AND THE
Jolly Buoy Island in South Andamans (Alfred et al.,
2006).
Nearly 30% of the land has been lost in Katchal
Island. Trinkat Island has almost been split into three
pieces (Ramachandran et al., 2005). Katchal Island is
unique for nesting of green, hawksbill, olive ridley
and leatherback turtles. Leatherback turtle nesting
grounds in Car Nicobar and Great Nicobar have been
affected. The nesting beaches in South Andaman,
Little Andaman, and the Nicobar group of islands
have almost vanished as all these islands have gone
down by one to three meters. In the east coast of
Great Nicobar, the Galathea, an important sea turtle
nesting ground was affected. Little Nicobar has also
borne the brunt of tsunami waves. Many islands of
Andaman and Nicobar group shifted southwestwards.
Many areas in Andaman and Nicobar Islands showed
levels of subsidence on joint impact of earthquake
and tsunami.
The latest generation of leatherback, green,
hawksbill, and olive ridley turtles has been washed
away. The nesting beaches in South Andaman, Little
Andaman, and the Nicobar group of islands have
almost vanished as all these islands have submerged
by one to three meters due to tectonic activity
(CORDIO/IUCN, 2005). This will have an impact on
the reproductive potential of leatherback, green,
hawksbill and olive ridely turtles which nest along
these islands. The popular leatherback nesting sites
in Great Nicobar Island like mouths of Galathea,
Alexandria and Dagmar rivers (Bhaskar, 1979) have
also been affected due to tsunami.
Several new beaches have formed in these
islands (Jackson Creek – at northern mouth side to a
length of 5 km and a 2 km long beach at 4 km south
(Sarang Kulkarni, 2005)) and some turtle nesting in
these new sites has also been reported after the
tsunami event. The important leatherback turtle
nesting sites in Mahatma Gandhi Marine National
Park escaped from tsunami. Due to the tsunami, the
sand and sediment from land have been deposited on
the sea grass beds which will have a long term
impact on the population of dugongs (Sarang
Kulkarni, 2005). The litter scattered on the beaches
is a real threat to the nesting turtles (Ramachandran
et al., 2005). The turbidity of the coastal waters will
have an effect on the sea grass ecosystem. Loss of
sea turtle nesting habitat due to sand removal in
beaches in Camorta, Katchal, Nancowry and Trinkat
has been observed (Ramachandran et al., 2005).
Though the sand cover has increased in Camorta and
Nancowry Islands, the same has considerably
reduced in Katchal and Trinkat Islands.
The data on sea turtles is really lacking in many
places of the islands due to difficulty in continuous
monitoring owing to inaccessibility. So, it will be
difficult to make comparison with the post tsunami
event and to assess the change in pattern. The
tagging study itself is not comprehensive and so it

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will be difficult to compare the data. The foremost
importance is to take up a comprehensive study on
all aspects in all places of the islands and create a
database. Collaborative studies with neighbouring
nations are also essential
migration/foraging pattern.

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