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ECOLOGICAL
CONDITIONS FAVOURABLE FOR SEA TURTLES
In coastal Orissa, the area of confluence of any river and the
sea, which is the deltaic region, is a fascinating ecosystem.
Also called intertidal area, this is criss-crossed by estuary,
rivers, creeks and creeklets. The land in these estuaries is continually
inundated by the saline sea water under influence of sea tide
and also sweet water of river. Such lands are covered with mangroves,
a kind of vegetation endemic to these areas. The mangroves and
the estuaries are the breeding and spawning grounds of varieties
of marine life forms such as fishes, prawns, crabs and mollusks.
These life forms spend their juvenile stage in the mangrove estuarine
ecosystem, and migrate to the sea in the later part of their lives.
October to May is the period during which these juveniles are
available in abundance in the estuaries and the coastal sea. This
is the time for the sea turtles to congregate in these areas,
having migrated over large distances in the sea to feed on these
fishes etc. in the shallow sea near the intertidal regions. During
the months of October to May therefore, shallow sea near the river
mouth becomes the feeding ground of the sea turtles, both for
the adults and their juveniles. The sea turtles congregate and
mate there and then look for suitable undisturbed beaches in these
river mouth areas for laying eggs and nesting.
Based on these ecological conditions, certain pockets in the Orissa
coast have become the famous mass nesting sites of the Olive Ridley
sea turtles. Significant populations of these turtles visit the
congregation areas en-masse before the winter months for breeding
and nesting. This is a yearly phenomenon. This population represents
about 50% of the total world population of Olive Ridleys, and
about 90% of the Indian population of sea turtles. Worldwide attention
is naturally focused on these rookeries for conservation of this
species.
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SPECIES
OF SEA TURTLES
Out of eight species of sea turtles found in the world, five species
inhabit the Indian coastal waters. Of these, four species of sea
turtles are found in Orissa. They are the leather back (Dermochelys
coriacea), the Green (Chelonia mydas), the hawksbill (Eretmochelys
imbricata) and the Olive Ridley (Lepidochelys olivacea) sea turtle.
Out of four species found in the coastal waters of Orissa, Olive
ridleys are the only species found nesting on the coastline of
the state. The nesting sea turtles stay for considerable amount
of time in the shallow waters on the continental shelf from October
to May, each year.
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LEGAL
STATUS
The Olive ridleys are Schedule I species under the Wildlife (Protection)
Act, and are listed as 'endangered' in the IUCN Red Data Book,
in the 'Appendix-I' of CITES (Convention on International Trade
in Endangered species of wild Flora and Fauna), and also listed
in the CMS (Convention on Migratory species). India being a signatory
nation to all these conventions has the responsibility of protecting
this species of sea turtle and its nesting beaches, breeding,
feeding and congregation areas, as well as its migratory pathways
in the sea.
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NESTING
AREAS AND MAIN ROOKERIES
Olive Ridley sea turtles come to Orissa coasts for nesting in
large numbers. Hence the activity is termed 'mass nesting' or
'arribada'. Worldwide attention is focused on the conservation
of Olive Ridley Sea Turtle (Lepidochelys olivacea) in Orissa because
about 50% of its world population comes to Orissa coasts for nesting,
and this is about 90% of the population of sea turtles along the
Indian coast.
During the period from October to early summer,
shallow seas near the river mouths become ideal feeding grounds
for the Olive Ridley Sea turtles. At these places they also
breed and look for undisturbed beaches for nesting.
The known major breeding grounds in Orissa where
such congregation takes place are located near the river mouths
off Dhamra, Devi, and Rushikulya, although there are also minor
breeding grounds near other river mouths such as the Mahanadi,
Subarnarekha, Budhabalanga, Keluni and Bahuda.
The famous mass nesting site of Olive Ridleys close to the mouth
of Brahmani-Baitarani (Dhamara), received worldwide recognition
in 1975-76 as one of the largest rookeries of the Ridleys.
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THREATS
The sea fishing activities have direct adverse
impact on the adult sea turtles and their hatchlings. Olive ridleys
usually mate between October to February, when they congregate
in the shallow coastal waters for prolonged periods, making them
vulnerable to the fishing nets and propellers of the trawlers.
The other threats to sea turtles include: (i) Loss or modification
of the nesting beaches due to Casuarina plantation; (ii) Fishing
by gill nets; and development of fishing bases at the potential
nesting sites and breeding areas; (iii) Strong illumination around
nesting beaches which greatly disorients the adult turtles as
well as the hatchlings; (iv) Large scale vessel movement in congregation
zones severely disturb mating and breeding; (v) Nests and eggs
are destroyed by predators like dogs, jackals, hyenas, etc., and
by beach erosion.
The most significant of these threats is 'incidental catch' in
marine fisheries (where a few thousand turtles are killed in trawl
and gill nets every year), as well as depredation of turtles eggs
by feral and wild predators. |
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POPULATION
ESTIMATE OF NESTING SEA TURTLES
Population Estimation Technique
Recorded figures of the number of turtles which laid eggs in different
rookeries and the number of turtle casualties detected in different
years are as follows:
|
Year |
No. of
Nesting Turtles at Rookeries (in lakhs)
|
No of turtle casualties
detected along the Orissa coast during the year
|
Fishing vessels seized
in Gahirmatha Marine Sanctuary |
|
Gahirmatha
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Devi
|
Rushikulya
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1998-99 |
2.98 |
Not
counted |
No
mass nesting |
13,671 |
50 |
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99-2000 |
7.11 |
25,000
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No
mass nesting |
15,732 |
18 |
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2000-01 |
7.41 |
No
mass nesting |
1.59 |
5,483 |
37 |
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2001-02 |
No mass nesting
|
No mass nesting
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0.35 |
12,977 |
135 |
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2002-03 |
0.73 |
No mass nesting
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2.08 |
10,086 |
63 |
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2003-04 |
2.43 |
No mass nesting
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2.01 |
4,981 |
37 |
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* Gahirmatha: (Dhamara
river mouth to Mahanadi river mouth) |
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PROGRAMMES
AND ACTIVITIES:
* Declaration of Gahirmatha Marine Wildlife Sanctuary in September,
1997.
* Formation of State Level Steering Committee for sea turtles
under the chairmanship of Chief Secretary, Orissa in 1997.
*Declaration of three major turtle congregation sites (nesting
and breeding grounds) at Gahirmatha (Dhamara river mouth), Devi
and Rushikulya River mouths as 'No Fishing Zones' during the reproductive
and nesting period.
*Use of 'Turtle Excluder Device' (TED) has to be mandatory in
all trawl fishing nets.
*Regular patrolling of the nesting beaches and congregation-breeding
zones in the sea by setting camps along the sea coast, and by
patrolling in sea by trawler.
*Monitoring the nesting beaches against predators and human interference.
*Motivating local people in conservation of the breeding and nesting
turtles.
*Awareness creation among the fishing community and local inhabitants
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| Conservation
highlights during 2003-04
· The nesting beaches were
protected from biotic interference, and efforts have been made
to keep them in proper condition for nesting of sea turtles and
safe emergence of the hatchlings.
· Monitoring has been done by setting of camps at strategic
locations on the shore to cover all nesting areas. 26 camps were
set up covering 44 nesting beach segments on the entire Orissa
coast.
· A Central Monitoring Unit (CMU) functioning in the office
of Chief Wildlife Warden, Orissa coordinates and monitors day
to day activities relating to Sea turtle conservation.
· Sea patrolling was launched from six offshore camps.
Prohibition against trawl and gill net fishing was enforced in
the turtle congregation zones in the coastal sea by taking up
patrolling of these areas.
· VHF communication among the camps and
forest offices in the coastal area was strengthened through 15
VHF Main sets and 12 Handsets.
· Joint patrolling was done involving the
Coast Guard and State Fisheries Department.
· A total of 37 fishing vessels / boats
which were doing illegal fishing in the prohibited zone were seized
and kept in the custody of forest officials and legal action has
been initiated against the offenders.
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