2 years ago

Turtles in Trouble



Turtles in Trouble: Top 25+ Endangered Tortoises and Freshwater Turtles—2011Southern River TerrapinBatagur affinis (Cantor 1847); Family GeoemydidaeAsia: Cambodia, Indonesia (Sumatra), Malaysia (West), Myanmar (?), Singapore (extirpated), Thailand (extirpated?), Vietnam (extirpated)IUCN Red List: NE, Not Evaluated; TFTSG Draft: CR, Critically EndangeredCITES: Appendix IThe plight of this species underscoresthe importance of proper taxonomy inconservation of wildlife. This criticallyendangered large river turtle was untilrecently considered to be a wide-rangingspecies (from India to Indonesia), but geneticanalysis determined that it was twoseparate species: the Northern River Terrapin,Batagur baska, and the SouthernRiver Terrapin, B. affinis. A recent studyhas further split B. affinis into two subspecies:the Western Malay River Terrapin,B. a. affinis, and the Eastern MalayRiver Terrapin, B. a. edwardmolli.Living in the estuaries of large riversand their associated mangroves, as wellas in the upper reaches of the rivers, B.affinis was once a highly abundant speciesthat was well integrated into humanculture. Often the eggs of these turtleswere so highly esteemed that they weredeemed the sole property of the ruling kings. Sadly, theturtles were overexploited for their flesh and eggs and onlysmall isolated populations remain. Much like its sister speciesto the north, habitat loss and degradation such as rampantsand-mining, dam construction, and pollution have alsogreatly exacerbated this species’ decline. In addition, largescaleshrimp farms that discharge effluents into rivers causesalinization and negatively impact turtles by killing many ofthe aquatic plant species that they feed upon.Today there are multiple conservation projects forB. affinis in the countries where it still occurs, however,these programs are not well integrated. Additionally, theprograms have not yet been able to focus on reducing adultmortality and have only been successful in securing thehatching of offspring from nests laid naturally or at captivebreeding centers.Distribution of Batagur affinis.Batagur affinis male in breeding color from Setiu River, Malaysia. Photo by Eng Heng Chan.In Peninsular Malaysia, where some wild breedingpopulations still exist, government programs have focusedon egg incubation, headstarting, and release. This approachhas not been successful in arresting the decline of the speciesalong the west coast of the peninsula, where the numberof wild clutches deposited have plummeted from a fewthousand to less than 40 in just the past 20 years. It is believedthat rampant poaching of terrapins for illegal tradealong the west coast has contributed to the rapid decline ofthis region’s turtle populations. Yet, a similar conservationapproach on the Terengganu River on the east coast of thepeninsula appears to have helped sustain a small nestingpopulation. As recently as 2008, 100 wild nests were collectedalong this river for incubation.A research and conservation project initiated in 2004on the population on the Setiu River on Peninsular Malaysia’seastern coast has made headway into some longunanswered questions about biology and the effectivenessof headstarting for the species. Monitoring of releasedheadstarted terrapins has demonstrated their ability tosurvive and grow in the wild, but whether they survivethe 10–20 years needed to reach sexual maturity remainsto be seen.In Cambodia, where the species was previouslythought to be extirpated, the recent discovery of a verysmall population of no more than a handful of nestingadults has received focused conservation attention from theWildlife Conservation Society with support from ConservationInternational and the Turtle Conservation Fund.– 34 –

Turtles in Trouble: Top 25+ Endangered Tortoises and Freshwater Turtles—2011Red-crowned Roofed TurtleBatagur kachuga (Gray 1831); Family GeoemydidaeAsia: Bangladesh, India (Bihar, Madhya Pradesh, Punjab, Uttar Pradesh, West Bengal), NepalIUCN Red List: CR, Critically Endangered A1cdCITES: Appendix II, as Batagur spp.The last known stronghold for thislarge river turtle (up to 60 cm carapacelength) is on the Chambal River incentral India, however, small isolatedpopulations may still exist in the Gangesand Brahmaputra River basins, includingin Bangladesh. It has also beenreported as very rare in Nepal, whereit breeds along a few rivers. No morethan approximately 500 adult femalesremain of a species that once had avery large range. The species has beendecimated due to high levels of huntingand habitat degradation, includingpollution and large-scale water extractionprojects for agriculture and drinkingpurposes. The main anthropogenicthreats to the remaining population areaccidental drowning of adults in illegalfishing nets, sand-mining, agriculturalcultivation on sand banks and bars, water diversion, andirregular flow from upstream dams.The species demonstrates marked sexual dimorphism,with males being more brightly colored and smaller thanfemales. Males during the breeding season display vibranthead patterns with bright blues, yellows, and reds. Expressionof breeding coloration to this extant is very unusual inturtles. Females nest from March through mid-April, laying11–30 eggs that hatch just before monsoonal rains aftera nearly three-month incubation period.The Turtle Survival Alliance, the San Diego Zoo Institutefor Conservation Research, and the Madras CrocodileBank Trust have been jointly engaged in a conservationprogram on the National Chambal (River) Sanctuary since2005. This has had good success, with a series of riversidehatcheries, two headstarting rearing facilities, poacherconversion initiatives, and public awareness campaigns.Distribution of Batagur kachuga.Batagur kachuga male in breeding color from Chambal River, India. Photo by Brian D. Horne.To date the program has produced over 4000 hatchling B.kachuga; however, during the monsoon rains that flood theriver, released turtles may leave the sanctuary and the protectionit affords and migrate to less protected or unprotectedsections of the river.With the presumed low survival rate of hatchlingsto adulthood (a minimum of 10–15+ years is required toreach maturity for females); there is great need to maintainproduction of thousands of hatchlings per year to hopefullyoffset the decline of turtle populations in the ChambalRiver. The determination of survival and movementthrough radio-tracking of headstarted juveniles is neededto gauge the success of the project. Additional captive assurancecolonies need to be developed to help maintainan adequate genetic diversity of animals in case the singlelargest population of these turtles is lost due to a man-madeor natural disaster. Currently the species is captive-bred atMadras Crocodile Bank and captive colonies are beingmaintained there and at Kukrail Gharial (and Turtle) RehabCentre in Lucknow. This needs to be expanded in otherzoos and captive centers across the species’ historic range.Additional surveys need to be conducted to determine ifthere are any other remaining populations. Reintroductionprograms should be initiated along other protected habitatssuch as the Son, Kane, Betwa, and other rivers in the historicrange. Continued efforts need to focus on reducingthe incidental by-catch of this species in fishing nets. Newsurveys have been launched in Nepal by CARON and inBangladesh by CARINAM to determine the current statusof those populations.– 35 –

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