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Green Sea Turtle
Chelonia
mydas japonica
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| FACT FILE: |
| Local
Name: |
Sabaaz
Kchuwa
(Urdu) |
| Family: |
CHELONIIDAE |
| Genus: |
Chelonia |
| Status: |
Rare
and declining |
| Notes: |
Green
Turtles are rare and declining. Fish netting
should be avoided when doing deep sea
fishing.
If you find a new hatchling, please take it to the
sea and release it or contact WWF-Pakistan/Sindh
Wildlife Department |
|
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Photo Credit: WWF-Pakistan | |
Description
and Biology:
General
characteristics:
The Green Turtle is the largest of the hard-shelled sea turtles (the
Leatherback Dermochelys can grow much larger) although size, weight, and
carapace shape can vary markedly between different populations. Average
nesting female carapace length 80 to 110cm and weighs 110 to 185kg.
Biology:
The
Green Turtle eats exclusively seagrass and seaweed (algae). The Green
Turtle forages in shallow, inshore waters. Aggregations of Green Turtles
often occur over shallow-water seagrass pastures or other suitable
feeding grounds. Migrating Green Turtles may travel 20 to 40km per day.
It is suggested that migratory behaviour is particularly linked with
herbivory, since the richest feeding grounds (notably sea grasses) are
most often found in shallow areas of coastal deposition, and do not
typically coincide with the best nesting grounds (often isolated
predator-free island beaches). Females do not attain maturity in the
wild for 15 to 50 years. After a period of two to five decades, females
typically migrate to a nesting beach often used by aggregations of
turtles. Females remigrate at intervals of three years, and may lay
three clutches of 100 to 120 eggs. Hatchlings emerge mostly at night
from eggs buried in beach sand and make their way to the sea.
Habitat,
Distribution
and Status: The
beaches of Pakistan are some of the most important nesting grounds for
the Green Turtles. Each year thousands of female Green Turtles come to
the beaches of Hawksbay and Sandspit off the coast of Karachi to lay
their eggs. The Sind Wildlife Department in collaboration with WWF-Pakistan
is working on a project for safe release of turtle hatchling to the
Arabian sea since 1980's. Green Turtle nests are laid throughout the
year, with most nests occurring between July and December. The egg are
carefully kept in closed enclosers and released after the hatchlings are
hatched. Between
1980 and 1997 a total of 17,008 green turtle nests were recorded.
Numbers of nests since 1987 are apparently lower than the earlier years
of this initiative (Figure 1). To date, 3087 Green Turtles have
been tagged at this site and in addition to many local recaptures
individual females have been recaptured in India (Bhaidar Island, Gulf
of Kutchch Gujarat, 22°27'N 69°17'E), Africa (Beraisole, Eritrea, NE
Africa 13°39'N 42°08'E) and more recently in Iran (Between Lengeh and
Dayyer in the Persian Gulf, 27°45'N 52°15'E). Pakistan
has long been known to support a large population of Green Turtles Chelona
mydas (with a lesser number of Olive Ridleys Lepidochelys
olivacea), nesting primarily at Hawkes Bay and Sandspit near
Karachi, Sind Province. There have been indications that the remaining
coast of Pakistan, in Baluchistan Province (the Makran coast), may also
hold significant numbers of sea turtles. At least 95% of the Baluchistan
coast (>700 km long) consists of inaccessable and unfrequented sandy
beaches-apparently suitable turtle habitat. Three sources have provided
data on turtles in Baluchistan. Butler (1877) reported nesting by large
turtles, apparently C. mydas, on Astola (Haft Talar), a small
island some 25 km from the mainland. Butler stated "there is no
water on the island, which is barren, and only frequented by boats from
Muscat, which catch fish and large numbers of turtle". Although few
turtles were encountered on the nest beach on the evening of 28 May
1877, the shore was reportedly "strewn with the dry carcasses of
turtles which had been killed by Arab fishermen for the sake of their
oil...the stench along the beach in consequence was intolerable".
Shockley (1949) recorded that C. mydas was seen frequently
along the coast near Jiwani (Jiunri), adjacent to the border with Iran.
As many as a dozen large turtles could often be seen close inshore at
one particular "turtle cliff", and numerous turtle tracks
could be seen on the beach (in September-November 1945). Later, in an
unpublished letter (cited by Frazier, 1980), S. Telford reported
information from reliable sources that "many thousands" of
turtles were harvested from a beach at Ormara during 1975. Unfortunately,
the Wildlife Department is shorts of funds and faces many problems. It
is mainly due to these reasons that only 5,000 turtles have been tagged
during the past 20 years of the project, and scores of nests go
unnoticed every year.
As a result, stray dogs eat many eggs, some get disturbed due to the
movement of humans and fail to mature, whereas hundreds of hatchlings
die every year after being crushed under the wheels of moving vehicles,
since it is their natural instinct to move towards light, and in natural
conditions, the sea is the brightest object at night. Other than those
mentioned above, many threats exist in the region including: beach
development, fishing activities, noise from neighbouring villages,
pollution from a nearby harbour and exploitation of turtle products.
Figure
1
Credits:
Asrar,
F. F. 1999. Decline of Marine Turtle Nesting Populations in
Pakistan. Marine Turtle Newsletter 83:13-14 (http://www.seaturtle.org/mtn/archives/mtn83/mtn83p13.shtml)
Marine
Turtles in Baluchistan (Pakistan) Marine Turtle Newsletter
42:1-3, © 1988 (http://www.seaturtle.org/mtn/archives/mtn42/mtn42p1.shtml)
WWF-Pakistan
Nausherwan
Ahmed
©1997-2003 Wildlife of Pakistan-All Rights
Reserved.
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