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| Photo : Harry
Andrews |
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Crisis Response to Mass
Gharial Deaths in National Chambal
River Sanctuary |
January 1, 2008
The population of gharial crocodiles (Gavialis
gangeticus) has recently suffered a serious
blow. Since early December more than more than
65 gharials have been found dead
within a 35km stretch of the Chambal River,
which runs through the Indian states of Uttar
Pradesh, Rajasthan, and Madhya Pradesh. Though
there are several hypotheses as to the
cause of the deaths, to date there is no
definitive diagnosis and investigations are
continuing. The Chambal River gharial population
is the largest of only 3 remaining
breeding populations of gharial left in the
world. With estimates from 2007 population
surveys indicating 200-300 breeding adults left
in the world, the recent mass deaths pose
a significant threat to the species.
On December 9th Dr. Rajeev Chauhan of the
Society for Conservation of Nature (ScoN), an
NGO based near the Chambal River, received the
first reports of two dead gharials in the
village of Kasaua in the National Chambal
Sanctuary (NCS). Upon investigating these
reports Dr. Chauhan and Forest Department
officials found 5 gharial carcasses in NCS. The
Gharial Conservation Alliance (GCA) was informed
and began mobilizing a response.
Over the next few weeks more gharial carcasses
were found in NCS, and the known death toll
currently stands at 67. All dead gharials have
been sub-adults and young adults (5.5-10 feet
long), no mortalities of juveniles have been
reported. The sex ratio of the deceased gharials
has not been definitively determined, but a
significant number are believed to have been
males. There have been no reports of deaths in
other river wildlife. The dead gharials had no
external physical signs of injury, and necropsy
results indicated deaths were not due to
drowning in fishing nets, one of the most common
causes of mortality in gharials.
Several gharial necropsies (autopsies on
deceased animals) have been performed by the
Indian Veterinary Research Institute (IVRI), the
Veterinary College Jabalpur and ITRC.
Unfortunately most of the gharial carcasses
found were significantly decayed, making
post-mortem diagnosis difficult. A preliminary
report by IVRI concluded the cause of death was
failure of the liver and kidneys due to damage
caused by a protozoan parasite (Klossiella
species). Concentrations of lead and cadmium
were also found in the gharials, however these
levels were not high enough to have been
directly responsible for the gharial deaths.
Gharial researcher Dr. RJ Rao, of Jiwaji
University, has stated that
protozoan and helm ith parasites are fairly
common in gharials and other reptiles they have
studied, and do not usually cause mortalities.
Their previous studies of Chambal River water
quality and local fish have not revealed any
heavy metal contaminants or other significant
pollution. Recent water samples sent to several
research institutions in Madhya Pradesh and
Uttar Pradesh have not revealed any sources of
toxicity or pollution in the area where the
gharials have been found. However this does not
rule out the possibility of gharial feeding on
fish contaminated with toxins or pathogens that
may migrate from the heavily polluted Yamuna
River, which joins the Chambal at the
sanctuary’s lowest extremity.
Other hypotheses for the deaths have also been
suggested. After reviewing gharial necropsy
photos and case facts Dr. Fritz Huchzermeyer, a
South African crocodilian veterinary specialist,
has suggested the deaths may have been caused by
Pansteatitis, a condition caused by consumption
of rotten fish. Dr. Huchzermeyer, who is the
Vice Chair of Veterinary Science for the World
Conservation Union Crocodile Specialist Group (IUCN-CSG),
said Pansteatitis has caused mortalities in
South African crocodiles after a fish-die-off.
The condition causes hardening of the
crocodile’s fat, leading to decreased mobility
of the animal, and ultimately death by
starvation 6-8 weeks from consumption of the
fish. The fatty degeneration of the liver tissue
caused by this condition can appear similar to
the signs of cirrhosis, which may account for
preliminary diagnosis of cirrhosis in the dead
gharial. The most significant post-mortem sign
of Pansteatitis is deep yellow to orange-colored
fat. IUCN-CSG Chairman Dr. Grahame Webb has
officially urged participation of the IUCN-CSG
Veterinary Committee in the investigations and
response to this crisis.
The Gharial Conservation Alliance is working
with Forest Department Officials, Indian
researchers and veterinarians, the IUCN-CSG,
Worldwide Fund for Nature-India (WWF- India),
Wildlife Institute of India, and crocodile and
veterinary experts from around the world to find
the cause of this devastating die-off and take
immediate action. GCA researcher Dhruva Basu is
currently in the Chambal River working with
local officials and veterinarians to investigate
the crisis. The team is taking samples from live
gharial in the area, particularly those that may
appear sick, as well as sampling other flora and
fauna, for more clues on the cause of the
mortalities. One 3 meter female gharial that is
in an advanced stage of the disease has been
corralled and is being experimentally treated
with a combination of antibiotics, liver
supplements, pulmonary stimulants and cortisone.
West Asian Regional Chair of the IUCN-CSG, Mr.
BC Choudhury, is conferring with international
and national authorities about this crisis. At
the behest of WWF-India the Ministry of
Environment and Forests will be hosting a
meeting in Delhi with the GCA,
government officials, veterinarians, and all
involved parties to review evidence and
formulate a plan of action. The Principle Chief
Conservator of Forests in Madhya Pradesh, Dr.
P.B. Gangopadhaya, has sent a letter to the
Indian Ministry of Environment and Forests
urging immediate action and suggesting this be
declared a national conservation emergency.
Vigilant monitoring of the Chambal River and
thorough investigations into possible causes
must be continued.
Those wishing to contribute
to the Chambal Gharial Crisis Response
financially or otherwise can CONTACT
US here
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