Chambal River Sanctuary Program Protects Two Species of Sympatric Batagur
Large batagurid turtles of the genus Batagur are probably the most threatened freshwater turtles in India. Their populations have been immensely reduced due to multiple factors such as poaching, accidental drowning in fishing gear, and habitat destruction. They have all but disappeared from most of the Ganges river system, one of the world’s largest watersheds.
Reports from the 1980’s and 1990’s documented the Indian Red-Crowned Roofed Turtle, Batagur kachuga as a rare species, and the Three Striped Roof Turtle, Batagur dhongoka as rapidly declining. The Chambal River (the name sake of the National Chambal Sanctuary), has received moderate protection as India’s only protected riverine habitat for three decades, and is believed to be one of the last strong holds for these two species but even here, B. kachuga are rare.
In four field seasons (2006-2009), our program has been highly successful. We have been able to protect over 300 B. kachuga nests and 1,700 B. dhongoka nests in 11 different riverside hatcheries.
In mid-January 2009, we started our annual nest surveys and nest protection programs in the Uttar Pradesh and Madhya Pradesh sections of National Chambal Sanctuary. To date, we have not been able to establish a nest protection program in the Rajasthan section of the river. We hope to do so in the near future. Yet, we were able to survey over 400 km of river to record nesting locations, nesting density, nest depredation rates, and anthropogenic pressures on the turtles. From these data, we were able to prioritize the protection of nesting habitat through the use of a Habitat Suitability Index (HSI), which in turn allowed us to determine where to establish our three in-situ hatcheries.
Thus, we were able to protect 90 B. kachuga and 157 B. dhongoka nests in our hatcheries this year that would have otherwise most likely been destroyed by jackals (Canis aureus). Over 3,800 hatchlings were released within 24 hours of nest emergence. We were able to mark 1,300 of these hatchlings with injectable decimal coded wire tags as well as plastic color tags (small self locking cable ties attached through a 3 mm hole in a posterior marginal scute) before releasing them into the Chambal River for survival and migration studies.
Hatching success rates for the two hatcheries in Uttar Pradesh were 99% in Uttar Pradesh and hatching success rate for the single hatchery in Madhya Pradesh was 92%.
We shifted approximately 150 newly hatched B. kachuga to the new head-starting facilities, where we will maintain them until they attain a mass of 1 kg (approximately three years of age).
Although we are succeeding at protecting nests on a few important nesting banks, there is still a great need to expand our efforts due to the population of adult turtles remaining relatively low. Furthermore, our future efforts need to address the continued human induced pressure on the survival of adult turtles. With the presumed low survival rate of hatchlings and the lengthy maturation rate (an estimated 15-20+ years to reach maturity for females), we need to sustain the production of thousands of hatchlings per year if we hope to reverse the decline of turtle populations in the Chambal River. In addition, we need to develop an in-depth understanding of the nesting ecology and long-term yearly trends for both species. New research initiatives need to include the post-release survival of headstarted turtles to gauge the success of these programs.
With limited opportunities and resources, this year we again enlisted services of members of fishing communities and riverside agriculturists in our turtle hatch-release and survey programs. After their employments with us, they gave up their riverside agriculture and we were able to protect three important turtle nesting banks and about 60+ turtle nests.
Additional surveys outside the Chambal National Sanctuary along the Ghaghara, Kane, and Son Rivers are being conducted in hopes of finding additional habitats suitable for release of our head-started B. kachuga. In the near future, we plan to survey another river- Betwa - where Madhya Pradesh Forest Department released over 100 Batagur (unknown ratio of B. kachuga to B. dhongoka) in 2003.
With the generous support from Turtle Conservation Fund, Disney Worldwide Conservation Fund, and the Beneficia Foundation, we have expanded our in-situ turtle rearing capacity at both the Garhaita Turtle Rehabilitation Center and Deori turtle centers. These funds enabled us to maintain over 1,000 B. kachuga of different age classes for the headstarting program.
A defunct Gharial facility at the state-run Deori Eco-Center was renovated while a new facility was built at the Garhaita Turtle Rehab Center (GTRC) near the town of Etawah. Both these facilities (16 X 5 X 1.5 m) are equipped with floating basking and nesting platforms. We transferred over 300 B. kachuga (2003-2007) and 20 B. dhongoka in the new facility at Deori this May. We are planning to begin releasing the 2003-2005 turtles in the spring of 2010. Turtles will be equipped with long-lived sonic transmitters to monitor their movement as well as survival.
We transferred over 200 B. kachuga and 100 B. dhongoka yearlings (2006-2008) to the new facility of GTRC, which will be soon equipped with a bio-filtration pond and a solar powered pump to make it a water and energy-efficient facility, a necessity in the water- scarce Chambal region.
- Shailendra Singh and Brian Horne