Asian yellow pond turtle  (Mauremys mutica)

The Asian yellow pond turtle is classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

As its name suggests, the Asian yellow pond turtle (Mauremys mutica) can be distinguished by its characteristic yellow markings, which consist of a yellow throat, a yellow-green forehead, a yellow plastron with black blotches (2) (4), and a light yellow or ivory-coloured stripe from the eye to the neck (2) (4) (5).

The slightly domed carapace of the Asian yellow pond turtle is usually brown to black, although its colouration varies considerably over the species’ geographic range (4) (5). The head and neck of the Asian yellow pond turtle are grey to dark olive above (4), while both the limbs and tail are grey to olive above and paler greyish-yellow below (4) (5). The limbs of this species are well developed and have fully webbed toes (5), and the turtle’s snout is conical and slightly projecting (4).

Unusually among species in the Geoemydidae family, the female Asian yellow pond turtle is not significantly larger than the male, with the adult male carapace length often being equal to, or even greater than, that of the adult female (5). The male Asian yellow pond turtle can be distinguished from the female by its more concave plastron and longer, thicker tail (4) (5).

Populations of the Asian yellow pond turtle in the southern Ryukyu Archipelago in the East China Sea have diverged considerably from other populations of this species, and are now recognised as a distinct subspecies, the Ryukyu yellow pond turtle (Mauremys mutica kami). This subspecies has a lighter carapace than Mauremys mutica mutica, ranging from light grey to yellowish or tan, and the yellow or ivory stripe behind the eye is absent or indistinct (4) (5). Adult males of this subspecies have a significantly greater carapace length than females (5).

The Asian yellow pond turtle is widely distributed through tropical and temperate East Asia, occurring in northern Vietnam, southern and central China, Japan, and on the islands of Hainan, Taiwan and the Ryukyu Archipelago (1) (2) (4) (5) (6). The subspecies M. m. kami is found only in the Ryukyu Islands (4) (5).

The distribution of the Asian yellow pond turtle within the island regions of its range is highly fragmented, and these populations, as well as populations in parts of central Japan, are thought to have originated from deliberate introductions from Taiwan (5).

A semi-aquatic species, the Asian yellow pond turtle inhabits slow-moving bodies of water, including ponds, marshes, swamps and streams (4) (5) (6).

The Asian yellow pond turtle is omnivorous, with a diet which includes earthworms, insects, fish, tadpoles, snails and crabs, along with plant matter such as leaves, stems, seeds and fallen fruits (2) (5). This species is believed to remain in or close to water during the day, being most active at night and during rainy weather, when it sometimes ventures onto land (5).

Mating in the Asian yellow pond turtle is believed to lack the ritualised courtship behaviour of other similar species, with the male simply approaching and attempting to mount the female (4) (5). This may explain the larger relative male size in the Asian yellow pond turtle when compared to related species (5).

The Asian yellow pond turtle’s breeding behaviour has been well studied in captivity. Eggs are usually laid between April and August, and females produce an average of around two clutches annually, each of which contains one to eight eggs (2). The eggs hatch after an average of about 94 days at 30 degrees Celsius, and the hatchlings measure up to 3.3 centimetres in length and weigh between 5 and 8 grams (4).

The majority of Asia’s freshwater turtles are threatened with extinction (7) (8), and the Asian yellow pond turtle is no exception (1). This ‘Asian Turtle Crisis’ is mainly attributable to largely uncontrolled trade for food, traditional medicine and pets (7) (9) (10), driven primarily by increased demand in China (7) (11).

The Asian yellow pond turtle commands a high market value and has become one of the most commonly traded turtles in Asia (12). With market supplies decreasing (1), this turtle has also recently become a focus of aquaculture (12).

Turtle farming is widespread in China (13), with many operations illegal and unlicensed (14). Turtles are often intensively collected from the wild, and multi-species enclosures can lead to hybridisation (11) (13). Intentional production of hybrids between the Asian yellow pond turtle and Chinese three-striped box turtle or ‘golden coin’ turtle (Cuora trifasciata) is known to occur, with hybrids fetching high prices when sold as pure-bred golden coins (13). As newly described and seemingly rare ‘species’, hybrids are allocated high conservation priority, leading to concerns that conservation resources could be wasted on specimens which are not true species (13) (15).

Asia’s turtles are also affected by land use changes, habitat destruction, water pollution and the invasion of foreign species (2) (7). Life history characteristics of turtles, including delayed sexual maturity and a long lifespan, also increase their vulnerability to human pressures (10).

The Asian turtle trade was largely unregulated prior to 2002. However, since then several species of Asian turtle have been listed under the Convention on International Trade in Endangered Species (CITES) (9). The Asian yellow pond turtle is listed on CITES Appendix II, which requires export permits for international trade (3). Unfortunately, enforcement appears limited, and globally threatened species of turtle remain in trade in China (9).

Trade within China itself does not fall under CITES control (9), and although China has increased levels of protection for freshwater turtles in the last decade, the effectiveness of this protection appears limited (14). Data on captive breeding is lacking and it is unknown whether captive farming will be beneficial or harmful to species such as the Asian yellow pond turtle (11).

Find out more about the Asian yellow pond turtle:

• Ernst, C.H., Altenburg, R.G.M. and Barbour, R.W. (1997) Turtles of the World. ETI Information Systems Ltd, Netherlands. Available at:
  http://wbd.etibioinformatics.nl/bis/turtles.php

More information on turtle conservation:

• Asian Turtle Conservation Network:
  http://www.asianturtlenetwork.org/
• Turtle Survival Alliance:
  http://www.turtlesurvival.org/
• Turtle Conservation Fund:
  http://www.turtleconservationfund.org/