News & Events

River Terrapins Hatch Throughout Asia

by Rick Hudson 

Throughout Asia, from remote nesting beaches to captive breeding facilities, River Terrapins (genus Batagur) have recently completed their hatching season. The accounts below summarize information from the countries where TSA works on Batagur recovery programs including India, Myanmar, Bangladesh, and Indonesia.

The River Terrapins (Batagur) comprise six species of large, impressive, and at least in some species, spectacularly colored, turtles that once plied the great rivers and estuaries of southern Asia from the Indian Subcontinent to the islands of Indonesia. With five out of the six species listed as Critically Endangered or recommended for CR listing on the IUCN Red List, the six Batagur species have been a major conservation priority for TSA since its first field programs began in Asia, beginning in India with the Red-Crowned Roof Turtle, B. kachuga, in 2005, and continuing in 2006 in Myanmar with the Burmese Roofed Turtle, B. trivittata. Today, TSA has recovery programs for five species in India, Bangladesh, Myanmar, and Indonesia.

Even before the Asian Turtle Crisis‚Äîthe unprecedented level of wild collection of turtles for Chinese markets— struck in the mid 1990’s, Batagur were already in trouble.

Historically, Batagur have been among the most exploited turtles in southern Asia due to their predictable nesting habits and site fidelity. Turtle hunters and egg collectors know that the River Terrapins return to the same beaches and sandbars year after year within the same time frame. With both the eggs and the nesting females such easy targets, this extensive annual harvest of breeding females and eggs, exacerbated further by the capture of turtles in fishing nets, has caused chronic precipitous declines in most populations and reduced natural recruitment—down to almost nothing—in the most extreme cases.

Today five species persist only as remnant populations, restricted to tiny fragments of their former range, with a few barely clinging to existence. At least one species was believed extinct until a tiny remnant population was discovered in a remote river. Most Batagur now owe their survival and recovery to intensive conservation and management programs. Multiple organizations have come together in partnership to recover these species, and fortunately Batagur respond well to nest protection, hatching and head-starting. Indeed, for some species, these techniques have been responsible for boosting the captive population numbers far above those of their wild counterparts. The classic example is B. trivittata: with less than 10 nesting females, the TSA/WCS conservation program intervened just as the species was about to fall off the knife edge into extinction; now, there are over 600 in captive assurance colonies.

A similar situation exists for the Northern River Terrapin, B. baska: with no known wild nesting and the wild population teetering on extinction, TSA and Vienna Zoo established captive populations in Bangladesh and India by bringing together long-term captive stock, which are now reproducing very successfully.

Although reintroductions of head-started turtles have been conducted in several countries –Myanmar, India, Indonesia, Cambodia Рit could be years before we understand the survival rate of these released turtles, their movements, and whether they will help establish new wild populations. Monitoring survival of Batagur is problematic in that standard radio-telemetry is fairly ineffective in deep riverine situations, requiring more advanced tracking technology which is expensive (sonic telemetry) or cost prohibitive (satellite telemetry).

Such technology is however necessary to adequately monitor these terrapins; Batagur often inhabit complex estuarine environments – consider the morass of channels and islands of the vast Sundarbans of India and Bangladesh – thus necessitating satellite telemetry if we are to truly understand their movements and survival.

Recovering wild Batagur populations remains one of our greatest conservation challenges, and will require vastly increased funding if we are to succeed. But for now, we are successfully applying standard conservation methods to build up captive numbers as a hedge against extinction in nature. Batagur recovery programs got a major shot in the arm in 2013 with a generous SOS – Save Our Species– grant that ran for two years. For more information on the SOS grant click here or here.

This award funded important work in India, Bangladesh and Cambodia and helped to develop and refine a regional model that could be used to recover Batagur species throughout their range.

Along with the Asian Box Turtles of the genus Cuora, Batagur represent the TSA’s most urgent conservation priority in Asia. The TSA now manages or supports programs for all six species of Batagur throughout south Asia.

Summary hatching results by country for 2016 are as follows:

India: With three target species, B. dhongoka, B. kachuga, and B. baska, the India program is the TSA’s most extensive Batagur program in Asia. The National Chambal River Sanctuary support two of the species, B. dhongoka and B. kachuga, and riverine hatcheries protect thousands of eggs annually from predation and return hatchlings to the river. This year a total of 598 nests (totaling 11,529 eggs) were relocated to protected hatching areas, resulting in 9,622 baby Batagur! Overall hatching success was an impressive 83%, reflecting the tried and true techniques of experienced field staff. Of these, 115 nests and 1,809 hatchlings were tallied from the Critically Endangered B. kachuga. Found only in India, the Chambal population represents this species’ stronghold. Two hundred of these young terrapins were selected for head-starting at two of TSA’s turtle centers on the Chambal River. Additionally 135 B. dhongoka hatchlings are being head-started at our Narora facility at Ganga, which TSA manages in association with our partner, Nuclear Power Corporation of India Limited (NPCIL).

TSA India also works on the recovery of B. baska in West Bengal, at the vast mangrove wilderness of the Sundarbans Tiger Reserve at Sajnekhali. Despite poor breeding success in 2015 due to high temperatures, 95 hatchlings of this critically endangered terrapin emerged from four nests in third week of May, bringing the total to 240 since this program got underway in 2012. This year we were able to release 10 juvenile B. baska from our project, with the intent to determine dispersal and survival.

Elsewhere in India, we have good news from our long-time partner, the Madras Crocodile Bank Trust, where seven hatchlings pipped from ten eggs on 16 May after an incubation of 51 days. This breeding success was the result of an international breeding loan, in which Peter Praschag sent a male B. baska to MCBT to pair with the two long-term captive females, both acquired from a market in Kolkata back in 2001. This effectively creates a much needed second assurance colony for this rare terrapin in India.

Bangladesh: Across the border in Bangladesh, at the Bhawal National Park facilities, our efforts with B. baska were not as impressive. After a disappointing year in 2015, when egg production dropped off after turtles were placed in smaller breeding groups for genetic management, we returned to a large group-breeding scenario and egg-laying increased. Unfortunately ants attacked the eggs late into the incubation period this year, and full-term embryos were discovered dead. Fortunately 146 hatchlings had been produced from this group from 2012 – 2015. Also on a positive note, one of the driving forces behind this program, Peter Praschag, reports that he produced 11 hatchlings at his facility, Turtle Island, in Graz, Austria.

Myanmar: 2016 proved to be a good year for B. trivittata as 27 hatched 13 May from a clutch of 30 eggs laid 26 February (in addition to 60 infertile eggs from four clutches.) This is particularly encouraging news, as it reversed the negative trend of the past two years in which reproduction within the wild population failed. With only 1 fertile egg out of 150 collected (8 clutches ) in 2014, and zero fertile from 117 eggs (5 clutches) in 2015, Steve and Kalyar Platt speculated that the few remaining egg-laying females (7-10) were not finding mates, with the males most likely lost to illegal fishing practices. It is therefore with a great sigh of relief that we celebrated this single fertile clutch this year.

Meanwhile, at the Yadanabon Zoo in Mandalay, 18 B. trivitatta hatched in 2016 from captive breeding, down from a high of 58 in 2015, but still an important event.

Probably the most endangered of all the Batagur, the turn- around for this species has been nothing short of remarkable. Rediscovered in 2001, a small captive nucleus was brought together for breeding in hopes of saving the species. However the discovery of a remnant wild population, still nesting along a remote stretch of the Upper Chindwin River, was responsible for building up the impressive numbers we have today in assurance colonies. Over 600 B. trivittata are being reared in three captive management centers throughout Myanmar, either being head-started for release or raised to adult size for captive breeding. The number of Batagur centers will expand to ensure that the population is distributed so as to avoid catastrophic loss and recently the Singapore Zoo received a group of 25 to further spread out the captive gene pool. Another 60 were released in 2015 with radio transmitters and are being monitored for movement patterns and survival. Our turtle conservation programs in Myanmar have been supported in recent years by the Critical Ecosystem Partnership Fund, who recently featured this project on their website.

Indonesia: In recent years TSA began directing modest support to Joko Guntoro and the Satucita Foundation’s fledgling Painted Terrapin, B. borneoensis, program in Aceh Province, Sumatra. Aceh supports what is believed to be one of the last remaining healthy B. borneoensis populations in Indonesia so it is critical that conservation actions be expanded there.

Built from the ground up starting in 2010, Joko and his colleagues began protecting nests that would normally be lost to egg collectors, incubating eggs and head-starting hatchlings for release. As donor support increased (thanks to Mohammed Bin Zayed and Chester Zoo) this program grew, and 2016 was a break out year as the number of nests and hatchlings increased by over threefold. This increased success is due to improved egg handling technique and increased man hours (140 days in 2016) on nest patrol due to adequate funding. Fifty eight nests were located and protected, which produced a program record 666 hatchlings, with a better than previous hatch rate of 70% . These turtles are being head-started for release in October.

Prior to this, 167 captive hatched B. borneoensis have been released back into native habitat, and this program has also done much to elevate the status of the Painted Terrapin at the national and local levels. As a result, legal changes are being proposed for expanding the level of protection for this species in Sumatra.

The Painted Terrapin is TSA’s first program in Indonesia, and expands our commitment to Batagur conservation by adding a sixth species to our ex situ efforts. The TSA is extremely pleased to announce a partnership with the Houston Zoo who is helping to support this effort, and we are proud of our association with Joko Guntoro who inspires us to believe in the future of turtle conservation in Indonesia.