I noted when I reviewed the new book on the freshwater chelonians of Hong Kong that the Chinese Pond Terrapin, Mauremys mutica does not appear. Those that were once found there were classified as Introduced because Hong Kong was said not to be within its known range. However, that is clearly not now the case, judging by the distribution map shown in the IUCN Red List (where it is called the Yellow Pond Turtle). I suspect that it should be considered as having been extirpated in Hong Kong by collection and habitat loss but occasionally restored if not sustainably by the release of captive specimens from the food markets.
In the wild this species has suffered a catastrophic decline in numbers over the past few decades. An 80% fall in three generations across Vietnam and China was IUCN’s estimate in 2018. It is now marked Critically Endangered. The Wikipedia article (which has a dreadful photograph of a stuffed specimen in Japan) provides a list of references which illustrate both the complexity of what might not be a single species and of difficulties of conservation through captive breeding and release of stock from farms. The species, along with many others, is farmed in China and there are examples of all sorts of weird hybrids turning up in captivity and in feral populations.
Mauremys mutica (then known as Clemmys mutica) was a regular in the wet markets of Hong Kong in the 1960s. The one I show here (photographed on the roof of the now-demolished Northcote Science Building of the University of Hong Kong) was bought in a Kowloon market by a lecturer, whose name I am still trying to remember, at what was then Hong Kong Baptist College, in 1966 or early 1967. She then released it in the wild in the New Territories.
The account in Karsen, Lau and Bogadek’s second edition of Hong Kong Amphibians and Reptiles published in 1998 described what was then known:
May be regarded as introduced. As an indirect result of the pet trade and traditional medicine trade, occasional specimens escape or are released. One specimen was found on Cheung Chau, having almost certainly escaped from a nearby temple where numerous species of terrapins were kept. Additional specimens were found in the vicinity of Shing Mun and Tai Tam Reservoirs, Sai Kung and Shek Kong areas. It is doubtful whether this species is part of Hong Kong's native fauna since these records lie outside the historic range, and there has been a recent surge in records in areas frequently visited by people.
All sorts of questions spring to mind. Did the ones released ever breed? Have they now all gone? It is perhaps worth noting that in the areas mentioned, Red-eared Sliders, the ubiquitous pet terrapin and also farmed in China for the human food market, are now commonplace. Have they outcompeted these as well as other native-to-China if not native-to-Hong Kong species?
Dire straits is the only description I can think of for status of the chelonian populations of China.