Photo credit: Arunima Singh

By Arunima Singh, Shailendra Singh, Rishika Dubla, and Jordan Gray

A
total of 68 hatchling Crowned River Turtles (Hardella thurjii) recently hatched at the Kukrail
Gharial Rehabilitation Centre (KGRC) in Lucknow, India, as part of a joint
project between Turtle Survival Alliance (TSA) / Wildlife Conservation Society
(WCS)-India and the Uttar Pradesh Forest and Wildlife Department.

The Crowned River Turtle is a large freshwater turtle found in the watersheds of the Ganges, Brahmaputra, and Indus river systems across Bangladesh, India, Nepal, and Pakistan. It is the single representative from the monotypic genus Hardella. Listed as Endangered by the IUCN Red List, extensive hunting and habitat degradation have severely depleted populations throughout its range.

Until
recently, knowledge on the ecology and remarkable incubation adaptation of this
principally aquatic species has been limited. In
light of the paucity of species knowledge, as well as the contradictory
information available, TSA-India continues to conduct a study in the Saryu
River of northern India. One objective of this field research is to elucidate
reproductive aspects key to its conservation breeding and incubation success.

In
November 2018, nine nests totalling 84 eggs were collected from the banks of
the Saryu and transported to the Laboratory for Aquatic Biology (LAB) at the
KGRC for incubation. Because wild nests of the species are commonly inundated
by flood waters during the monsoon season, the incubation period often includes
a diapause, or arrest in development. To increase hatching success, our program
simulates these natural conditions by inducing a diapause during artificial
incubation. On 22 May 2019, after nearly 8-months incubation, the first of the
68 hatchlings pipped their eggs, with all viable eggs completing hatching by 30
May 2019. By unlocking the key to the parameters of their diapause, our
hatching success has increased from 50 to 80%.

Photo credit: Shailendra Singh

The
goal of this project is to not only better understand the reproductive
particularities of this marginally understood species, but to also improve ex-situ breeding for future
supplementation of the dwindling wild population. This year’s cohort of
hatchlings will be retained at the LAB for several months before 75% are
released into the wild at the same site from which the eggs were collected. The
remaining 25% will be kept in captivity to bolster the gene pool of our
assurance breeding colony for the species.

This
project could not have been possible without the unwavering and continued
support from the officers and frontline staff of the Uttar Pradesh Forest and
Wildlife Department, and financial support from the WCS John Thorbjarnarson
Fellowship for Reptile Research.



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