Fresh Water Turtles of the River Ganga

By: Sandeep Behera
Water in the right quantity and quality is critical to the survival of aquatic biodiversity. Multiple threats take their toll, but uncontrolled and commercial exploitation by man has been the single-most damaging factor to species such as freshwater turtles of the Ganga. As an indicator species, freshwater turtle can provide invaluable information on the health of river Ganga’s ecosystem. Thus conservation efforts urgently need to be stepped up.
Wildlife

The Ganga and its tributaries drain about one square million kilometres of fertile basin in India that supports one of the world’s highest human population densities of 550 persons per square kilometre. In fact as documented in the study by A Mishra, 2010, titled Assessment of water quality using principal component analysis: A case study of the river Ganga, published in the Journal of Water Chemistry and Technology, almost half of our population lives on one-third of the landscape within 500 km of the Himalayan range, along the Gangetic plains. As a result, natural resources, especially water for domestic use and irrigation is severely constrained. There are some 30 cities, 70 towns and thousands of villages along the banks of the Ganga. Nearly all of the sewage from these population centres, over 1.3 billion litres per day, passes directly into the river (WWF 2003), along with thousands of animal carcasses, mainly of cattle. A large number of factories and industries like sugar, chemicals, fertilisers, small-scale engineering, pulp, cotton and tanneries are situated here with discharges that enter the river directly or indirectly and pollute to a considerable extent. An estimated 260 million litres of industrial wastewater, largely untreated, is discharged by hundreds of factories – while other major pollution inputs include runoff from the agricultural fields. More than 6 million tonnes of chemical fertilisers and 9,000 tonnes of pesticides are used annually within the basin (C M Wong et. al 2007, World’s top 10 rivers at risk, WWF-International, Switzerland).

WWF-India has been working for nearly two decades in the Upper Ganga region – Rishikesh to Narora, the 300 kms stretch passing through Uttarakhand and Uttar Pradesh, using sophisticated tools and methods to understand the status of indicator species and the health of the river ecosystem. The rate and magnitude of temperature rise, coupled with changes in water flow regime from run-off are key factors affected by climate change which are increasingly becoming a major global concern. Water in the right quantity, quality and season is not only critical to sustain human life, but is also a key to the survival of aquatic biodiversity. The change in behavioural parameters such as migration patterns, breeding, food availability for these species will affect the biology of the river system. There is evidence to suggest that the rate of climate change will be faster than the rate at which most species can adapt, either by migration or by changing their behaviour, physiology or form (S R Loarie et. al 2009, The velocity of climate change, Nature, London). A short-term goal for species management however – to ensure survival is by identifying threat processes and threatened species or communities. The conservation programme initiative in Naudevi and Bhairia villages in 2010 by WWF-India has been taken up as a pilot to improve livelihoods along with conservation. The project sites include villages in the Bulandshahar district of Uttar Pradesh.

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With 28 species of tortoises and freshwater turtles, India has one of the most diverse chelonian fauna in the world. It ranks among the top five Asian countries in terms of its importance for turtle conservation. Unfortunately, nearly 40 per cent of its turtles are listed as either endangered or critically endangered.

 

The Aquatic Species of Concern

The Ganga supports a rich fauna and flora, including the endangered Ganges river dolphin and at least 9 other species of aquatic mammals. Reptiles include 3 species of crocodiles along with one species of monitor lizard. Amidst these species there exists the exotic 11 species of freshwater turtles. While there are 378 known species of fish in the Ganga, the stock of most of the economically important fish has dwindled in recent years. Anthropogenic activities in the rivers and floodplains have adversely affected populations of migratory birds, and vultures have increasingly become rare.

Gavialis gangeticus or the gharial, a fish eating crocodile, and Aspideretes gangeticus, a soft shell turtle, are two endemic reptiles of the river. These species have been heavily exploited (the Kanjars and other tribes capture the turtle for food and it is also exported illegally) in the last few decades, which have pushed them near to extinction. Crocodylus palustris (crocodile of marsh) has also become rare in the river.

The endemic Gangetic dolphin is one of the most rare and endangered species in the river. An estimated population of about 2000 individuals of this species has been reported in the Ganga-Brahmaputra river systems. The species is facing severe threats ranging from habitat degradation (low water regime due to construction of dams and barrages and siltation), to impacts of pollution and unconventional fishing (reducing food base and by catch). It has been included under Schedule-I of the Indian Wildlife (Protection) Act, 1972 and has been awarded the maximum legal protection.

The Ganges river dolphin and the riverine turtles are two reliable indicator species of the health of the Ganga river ecosystem. This makes them species of special concern for WWF-India.

An indicator species is an organism that, by its presence in a biotope, denotes particular characteristics of that environment that would otherwise be difficult to determine. Studying indicator species could create the basis for a sustained research programme to see how the changes in the numbers of the said species can be related to the health of the river system. This would help to implement various programmes for restoration of the river system.

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The riverine islands, used for cultivation, serves as nesting grounds for freshwater turtles too. Farmers now have learnt to lessen the damage to turtle eggs during agricultural operations and safely collect the turtle nest and shift it to an ‘enclosed area’ created for the protection of the turtles.
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The riverine islands, used for cultivation, serves as nesting grounds for freshwater turtles too. Farmers now have learnt to lessen the damage to turtle eggs during agricultural operations and safely collect the turtle nest and shift it to an ‘enclosed area’ created for the protection of the turtles

 

Freshwater Turtles in the Ganga

In India, turtles play a very important role as religious symbols, both in folklore and culture. Turtles and tortoises can be found in temple ponds, tanks and enclosures. With 28 species of tortoises and freshwater turtles, India has one of the most diverse chelonian fauna in the world. It ranks among the top five Asian countries in terms of its importance for turtle conservation. Unfortunately, nearly 40 per cent (11 of 28 taxa) are listed as either endangered or critically endangered on the International Union for Conservation of Nature (IUCN) Red List. Multiple threats take their toll, but uncontrolled and non-sustainable commercial exploitation by man has been the single-most damaging factor. Freshwater turtles in the Ganga are divided broadly into two categories: hard-shell turtles (Emydid turtles) and soft-shell turtles (Trionychid turtles). The few studies conducted on Indian freshwater turtles have mainly dealt with taxonomy and their broad distribution ranges such as M A Smith 1933, The fauna of British India, including Ceylon and Burma: Reptila and amphibia, vol 1, Loricata, Testudines, Taylor and Francis, London; P C Pritchard 1979, Encyclopedia of turtles, T F H Publications, New Jersey; J C Daniel 1983, The book of Indian reptiles, Bombay Natural Historical Society, Mumbai; and Tikader and Sharma 1985, Indian testudines, Zoological Society of India, Kolkata. The lack of scientific information on the biology, ecology and population status of turtles is considered as one of the serious hurdles in devising management strategies for turtles in the Ganga. In addition, a large number of turtles are slaughtered for consumption. Due to lack of restriction on the capture of turtles and little or no enforcement of existing legislation, populations of turtles are decreasing (E O Moll 1984, Freshwater turtles in India: Their status, conservation and management, Hamadryad, IUCN). Freshwater turtles in the Ganga river are used for food and medicinal purposes. During fishing juvenile turtles caught in fishing nets as by catch, die due to drowning.

The Government of India, recognising the need to increase the population of different species of turtles, initiated a turtle rehabilitation project in the 1980s. This Project focused on hatching and releasing of young turtles at different sites in the Ganga River (D Basu 1987, Project for rehabilitation of freshwater turtle initiated in U.P, Hamadryad, IUCN). Although the Project was successful initially, the scientific understanding of the biology, ecology and population status of the turtles for proper implementation of further management programmes was still lacking. The strategy adopted by WWF-India demonstrated a species-led approach to river conservation with a strong focus on working at a local level and using the cultural and religious importance of the river as a means of engaging with rural communities.

 

Community and Conservation

WWF-India’s work on fresh water turtle conservation began in year 2007. Between 2007 and 2009, a study was carried out to understand the distribution, habitat preference/utilisation and conservation status of different freshwater turtle species in the Ganga river in a stretch of approximately 650 kms from Rishikesh to Kanpur. Habitat types were identified by recording river bank condition, vegetation characteristics (both aquatic and terrestrial) and water depth during summer. The habitat preferences of each turtle species was determined by field observations. Whenever turtles were sighted, the observations with respect to the species (if easily identified), number, sex, location, bank type, vegetation, river depth and velocity were recorded in the field map-sheets. All such observations were recorded considering the turtles’ activities like basking, nesting and feeding. In order to describe the habitat preference of the turtles, the Upper Ganga river was classified into the various habitat types, depending on the nature of the bank and the river depth during the dry season.

Suitable hydrological conditions are important for turtles to survive. Two key variables were studied to quantify the suitability of the water component: river velocity and depth. Turtles prefer river velocity ranging between 20 to 70 cm/s. Sections of the river with much higher velocity or lower velocity are avoided in favour of moderate velocity areas. This assumption is appropriate for a typical river with an average width of 500 to 1500 metres. The turtles often occur in water bodies with deep pools. The deep water provides them breeding habitat as well as cover while the shallow stretch of the river is used for foraging. A river with perennial flow will have the highest likelihood of supporting big turtles like Nilssonia gangeticus, Batagur kachuga, Batagur dhongoka and Hardella thurgii. Freshwater turtles show both daily and seasonal activity patterns – the former include feeding and basking while the latter relates to reproduction. All of these activities are influenced by changes in temperature. Basking behaviour of all hard-shell turtles is similar. During basking they raise their heads at an angle of 450o and rarely move far from water. The neck and limbs are fully extended to allow maximum sunlight coverage on the soft part of the body. Also certain preferred sites are used.

For the proper management of the Ganga river ecosystem and biotic resources bio monitoring is essential. Status of all endangered animals like turtles, crocodiles and migratory birds needs to be monitored systematically. Monitoring is also required to provide information on rates of change in population size and structure. Good population of higher vertebrates in the aquatic systems indicates a good population of other sympatric species and a safe, less disturbed habitat. Hence, human activities like agriculture and stone/sand mining on the riverbanks need to be controlled, and floodplains need to be restored to allow the natural breeding of aquatic animals such as the fresh water turtles and others.

Existing agricultural practices along the banks of Ganga river pose threat to the survival of the river dolphins and freshwater turtles. The usage of chemical fertilisers in agricultural fields result in nitrate pollution in the river, endangering in turn the species inhabiting the river. It was thus realised that communities need to be educated about the effects of agricultural practices on the habitat of these endangered species and develop alternatives to existing practices that strengthen conservation while ensuring livelihood security. To address the issue of leaching of chemical fertilisers, the use of vermi compost is being promoted in our pilot work.

Villagers practise mud flat farming during the dry season from October to June. These riverine islands are extremely suitable for the cultivation of crops of Cucurbitaceous family. However, the sowing season, coincides with the nesting season of the freshwater turtles. Prior to the initiation of conservation efforts, the nests of these turtles were either damaged during farming or they could not find appropriate sites for laying eggs. To lessen the damage of turtle eggs during agricultural operations locals are being trained to safely collect the turtle nest and shift it to an ‘enclosed area’ created for the protection of the turtles.

 

The RAMSAR Ganga

The declaration of 82 km of the Upper Ganga from Brijghat to Narora as a RAMSAR Site has enabled the participation of local communities in conservation efforts. The increase in the number of dolphins and turtles in this stretch in the last two decades as a result of reducing pollution loads and unregulated fishing is due to the change in behaviour of the local communities. People are now using bio-fertilisers on their fields and low cost traditional sewage treatment plants to stop the direct discharge of pollutants into the river. This has only been possible because local people now understand the importance of protecting the health of the river. The declaration of small aquatic protected areas, RAMSAR Sites or ‘No Go Zones’ seems to be bearing fruit. Even very small protected areas have great educational value, showing local people, including fishermen, the potential richness of aquatic life and sending a
strong message about human impacts on ecosystems.

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