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Molluscs of Pangong Tso, a High Altitude Brackish
Water Lake in Ladakh
Boominathan, M and Ramachandra, T.V.
Energy and Wetlands Research Group,
Centre for Ecological Sciences,
Indian Institute of Science, Bangalore.
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Introduction
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Pangong Tso is a trans-boundary
boundary lake between India
and China, situated at an elevation of 4300 m.
High Altitude Cold Desert Changthang Wildlife
Sanctuary (yet to be declared by State Govt. Jammu
and Kashmir).
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The lake harbours more than 300 species of birds, of
which most of them are migratory (Namgail and YomYom
Tov, 2009).
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About 100 species are known to breed here.
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This lake acts as a foraging ground for those birds.
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They feed on molluscs, insects, and worms (Namgail
and Yom-Tov, 2009).
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Even though, Pangong Tso wetland has international
importance for biodiversity, the studies on
invertebrates especially molluscs (which is one of the
important food for many breeding birds) are sparse.
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Sharma (2000) reported a fossil mollusc Radix
auricularia (Syn: Lymnea auricularia),
auricularia in the ancient
lacustrine clay deposits above the present level of the
lake.
Godwin-Austen
Austen (1867) reported dead freshwater
gastropod shells of Lymnaea and Planorbis, and a
bivalve shell Pisidium,, along the shoreline.
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Objective
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To explore the molluscan diversity of Pangong Tso
Lake.
Study area
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The study was conducted in this lake region on
September, 2010 near Merak village (Fig. 1)
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Figure 1. Pangong Lake and study site. Source: Googleearth, 2010.
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Study area
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Origin of Pangong Tso - Tectonic movements
(Williams, 1991), glaciation, and melt waters (Gujja et
al., 2003).
It receives water from numerous snow-fed
snow
streams
(Negi, 2002).
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The lake, depending on the water input, alternates
between saline and fresh water (Chang, 1987).
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Materials and Methods
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The pH were measured at the spot using EXTECH
electrode (EC500).
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Salinity were analysed in lab.
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The empty molluscs shells were handpicked from a 10
m belt along the shoreline.
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Stored in the plastic containers.
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The shells were identified using Ramakrishna and Dey
(2007).
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Results and Discussion
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The pH was 9.3 at Pangong Tso, such lakes with high
salinity and pH were reported by William (1991).
The salinity level of Pangong Tso Lake was 10.69 ppt,
which was brackish (500 ppm salinity being upper limit
for fresh water).
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The length of Radix brevicauda and Radix lagotis were
about 15 mm, from anterior (apex) to posterior (bottom
tip of aperture).
Fig 2a. Radix
brevicauda
Fig 2b. Radix
lagotis
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The length of Valvata piscinalis were about 5 mm
from anterior (apex) to posterior (bottom tip of
aperture).
Gyraulus sp. was about 5 mm in diameter.
Fig 2c. Valvata piscinalis
Fig 2d. Gyraulus
sp.
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Although all the four molluscs have been reported
from the water bodies of Jammu and Kashmir, this is
the first report for Pangong Tso.
Periostracum (outer thin organic layer) on the shell
surface indicates that this organisms are recent ones.
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Since the lake alternates between saline and
freshwater, freshwater molluscs are continue to live in
this lake.
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Conclusion
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Pangong Tso is a brackish lake; however, the
molluscs reported from this lake are of freshwater
origin.
Initiating long-term
term study of molluscs from this vast,
under-studied,
studied, pristine Himalayan lake using suitably
developed sampling methods, will lead towards a
breakthrough in documentation of mollusca.
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Such studies will help in preparing conservation
strategies for the rare biodiversity of lakes such as
Pangong Tso.
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Acknowledgements
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Tushar Prabhu, Rangarajan, Anshu Tomar,
Lieutenant-General,
General, and their team members.
Harish, Durgha, and Shankar Rao.
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References
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Chang WYB. 1987. Large Lakes of China, Journal of Great Lakes Research, 13(3):
235-249.
Godwin-Austen
Austen HH. 1867. Notes on the Pangong Lake District of Ladakh, from a
Journal Made during a Survey in 1863. Journal of the Royal Geographical Society of
London, 37: 343-363.
Gujja B, Archana Chatterjee, Parikshit Gautam, and Pankaj Chandan. 2003.
Wetlands and Lakes at the Top of the World. Mountain Research and Development,
23(3): 219–221.
Namgail T and Yom-Tov
Tov Y. 2009. Elevational range and timing of breeding in the
birds of Ladakh: the effects of body mass, status and diet . J Ornithol, 150:505–510.
150:505
Negi SS. 2002. Cold Deserts of India. Edition 2. Indus Publishing, pp 248.
Ramakrishna and Dey A. 2007. Handbook on Indian Freshwater Molluscs. Zoological
Survey of India, Kolkata.
Sharma VP. 2000. Geology of the Ladakh Region, J & K State with special reference
to High Altitude Lakes. Paper presented at National Consultation Workshop:
Conservation of High Altitude Wetlands. WWF-India,
WWF
Leh.
Williams WD. 1991. Chinese and Mongolian saline lakes: a limnological overview .
Hydrobiologia 210: 39-66.
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Thank you
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