Chinese giant salamander

Chinese giant salamander
Conservation status
Critically Endangered  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Caudata
Family:	Cryptobranchidae
Genus:	Andrias
Species:	A. davidianus
Binomial name
Andrias davidianus (Blanchard, 1871)
Synonyms
Megalobatrachus davidianus (Reviewed by Liu, 1950)[2]

The Chinese giant salamander (Andrias davidianus) is the largest salamander and largest amphibian in the world, reaching a length of 180 cm (6 ft), although it rarely—if ever—reaches that size today. It is endemic to rocky, mountain streams and lakes in China. It also occurs in Taiwan, probably as a result of introduction.^[3] It is considered critically endangered due to habitat loss, pollution, and overcollection, as it is considered a delicacy and used in traditional Chinese medicine. It has been listed as one of the top 10 "focal species" in 2008 by the Evolutionarily Distinct and Globally Endangered (EDGE) project. The Chinese giant salamander is considered to be a “living fossil.”^[4] This species is classified as critically endangered in the IUCN Red List because of a massive population decline of more than 80% since the 1950s.^[5]

Taxonomy

The correct scientific name of this species has been argued to be Andrias scheuchzeri (in which case Andrias davidianus would be a junior synonym) – a name otherwise restricted to an extinct species described from Swiss fossils.^[6] It has also been given the moniker of “living fossil” for being part of the Cryptobranchidae family which dates back 170 million years.^[4] It is one of only three extant species of the family, the others being the slightly smaller, but otherwise very similar Japanese giant salamander (Andrias japonicus), and the far smaller North American hellbender (Cryptobranchus alleganiensis).

Description

Portrait of a 30-year-old animal

It has a large head, small eyes, and dark and wrinkly skin. Its flat, broad head has a wide mouth, round, lidless eyes and the dark wrinkly skin has blotchy spots, and a line of pair tubercles that run around its head and throat.^[7] Its color ranges from dark brown to light orange.

The average adult salamander weighs 25–30 kg (55–66 lb) and is 115 cm (3.77 ft) in length.^[8] It can reach up to 50 kg (110 lb) in weight and 180 cm (5.9 ft) in length, making it the largest amphibian species.^[3][9]

Behavior

The Chinese giant salamander feeds on insects, frogs, crabs, shrimp, and fish. It has very poor eyesight, so it depends on special sensory nodes that run in a line on the body from head to tail. It is capable of sensing the slightest vibrations around them with the help of these nodes.^[10] The female lays 400–500 eggs in an underwater breeding cavity, which is guarded by the male until the eggs hatch after 50–60 days.^[3] Mating occurs between July and September.^[11]

The giant salamander is known to vocalize, making barking, whining, hissing, or crying sounds.^[12] Some of these vocalizations bear a striking resemblance to the crying of a young human child, and as such it is known in the Chinese language as the "infant fish" (娃娃鱼 / 鲵).^[13]

Distribution and habitat

The Chinese giant salamander was widespread in central, south-western and southern China, but its range is now highly fragmented.^[1] Its range spans the area from Qinghai east to Jiangsu and south to Sichuan, Guangxi and Guangdong; notably in the basins of the Yangtze, Yellow and Pearl Rivers.^[3] Finds in Taiwan may be the result of introduction.^[1]

The Chinese giant salamander is entirely aquatic and lives in rocky hill streams and lakes with clear water.^[3] It typically lives in dark muddy or rocky crevices along the banks.^[14] It is usually found in forested regions at altitudes of 100 to 1,500 m (300 to 4,900 ft),^[1] with most records between 300 and 800 m (1,000 and 2,600 ft).^[3] The salamanders also prefer to live in streams of small width (on average, 6.39 m or 21 ft across), quick flow, and little depth (on average, 1.07 m or 3 ft 6 in deep).^[15] Although they prefer to have quick flow in the stream, the burrows in which they lay their eggs often have much slower flow. Furthermore, their habitat often possesses very rocky, irregular stream beds with a lot of gravel and small rocks as well as some vegetation.^[15]

In captivity

As of early 2008, ISIS records only show five individuals held in US zoos (Zoo Atlanta, Cincinnati Zoo, and Saint Louis Zoological Park), and an additional four in European zoos (Zoo Dresden and Rotterdam Zoo).^[16] A medium-sized specimen, approximately 3 ft (0.9 m) long, was kept for several years at the Steinhart Aquarium in San Francisco, California, and is now on display again in the "Water Planet" section of the new California Academy of Sciences building.^[17] There are also two in residence at the Los Angeles Zoo. Additional individuals are likely kept in non-ISIS zoos and animals parks in its native China, such as Shanghai Zoo. Several of them are kept in the aquaria of Shanghai and Xian. It has been bred in captivity, but whether this can be achieved to an extent where the pressure on the wild populations is reduced is doubtful.^[3] The Osaka Aquarium Kaiyukan in Japan has both a Chinese and a Japanese giant salamander on display.

Since May 2014 thirty-three Chinese giant salamanders including three adults have been held in Prague Zoo. The main attraction is the largest specimen in Europe.^[18]

Decline in population

Chinese giant salamanders for sale in a restaurant in Hongqiao Town (虹桥镇) in Zhejiang, China: The price was 880 CNY/jin, or about 215 EUR/kg or US $280/kg. This places Chinese giant salamanders firmly in the luxury food segment and makes them an attractive target for poaching.

In the past, the Chinese giant salamander was fairly common and widespread in China.^[1] Since the 1950s, the population has declined rapidly due to habitat destruction and overhunting. It has been listed as Critically Endangered in the Chinese Red Book of Amphibians and Reptiles. Despite the Chinese Government listing the salamander as a Class II Protected Species, 100 salamanders are hunted illegally every year in the Hupingshan Natural Nature Reserve alone. Since the 1980s, 14 nature reserves have been established as an effort to conserve the species. Despite this, the population continues to decline with the salamanders becoming increasingly difficult to find. In a recent survey of the species in the Qinghai Province, none were found indicating the population size is at a significantly low number or the species is locally extinct in the province. This is believed to be due to the increased mining in the region.^[19]

In recent years populations have also declined with an epizootic Ranavirus infection. The disease causes severe hemorrhaging in both juveniles and adult salamanders. The virus was named the Chinese giant salamander iridovirus (GSIV).^[20]

Its natural range has suffered in the past few decades due to habitat loss and overharvesting. Consequently, many salamanders are now farmed in mesocosms across China. Furthermore, previously built concrete dams that destroyed the salamander’s habitat are now fitted with stairs so that the animal can easily navigate the dam and make it back to its niche.

The Chinese giant salamander is listed as a critically endangered species. It has experienced a drastic population decline, which is estimated to be more than 80% in the last 3 generations due to human causes. Human consumption is the main threat to the Chinese giant salamander. They are considered to be a luxury food item, as well as an important source of traditional medicines in China. They are easy to hunt, so catching them is not a problem. Breeding Chinese giant salamanders is a large industry with thousands of breeding and many enterprises.^[21] Hunters can sell their flesh for $100 American dollars per kg. There is also commercial farming of these species, but it is believed to originate from the wild. In the 1960s, more than 15,000 kg of Chinese giant salamander meat was harvested each year from a single prefecture in Hunan province. Habitat destruction including deforestation and pollution by humans is another reason for extinction. Water pollution from mines is an example of habitat degradation. The generation length of the Chinese giant salamander is estimated to be about 15 years. Since the 1980s, 14 nature reserves have been established for the conservation of the Chinese giant salamander.

Habitat destruction

According to a recent study, 90% of the Chinese giant salamanders’ habitat was destroyed by the year 2000,^[7] and there are many human-related causes of such massive destruction. Because the salamander dwells in free-flowing streams, industrialization is a large problem for many stream-dwelling species. The construction of dams greatly disturbs their habitat by either causing these streams to dry up or to stand still, thus making it uninhabitable by the salamanders.^[7] Siltation also contributes to the degradation of their habitats by soiling the water.^[7] Deforestation in areas near the streams can worsen soil erosion and create runoff into the streams as well, which reduces the water quality to a great extent.^[7] The reduced water quality makes it much more difficult for the salamanders to absorb oxygen through their skin and can often bring death to those within the species.^[7]

Water pollution is also a great factor in the habitat destruction of the Chinese giant salamander; the immense decline in their population can be traced to, among the other major problems of over-hunting and failed conservation efforts, the tainting of the water that they live in. Mining activity in particular in areas near their streams often causes runoff that sullies the water, and farming—and all of the pesticides and chemicals that affect the soil that come with it—has a vastly negative effect on the areas near the streams as well.^[22] The presence of macronutrients in the streams can also cause algal blooms, which cloud the water and force the temperature to rise.^[22] The salamanders reside primarily in very cold underwater cavities and follow a specific nesting requirement, which means that they will only reproduce and care for their eggs in areas such as these, so changes in temperature are incredibly detrimental to their health and well-being as well as to their perpetuation as a species.^[22] These algal blooms also deplete the levels of oxygen in the water, and a lesser supply of oxygen can quite easily hold the potential to kill off many members of the dwindling species.^[22]

Many efforts have been undertaken to create reserves and faux habitats for the Chinese giant salamander so that they can reproduce without worry of soiled water, but many of these reserves have failed in having a great impact overall due to the massive overhunting of the species. No matter how many members of the species they manage to save through the reserves, the poachers still manage to capture and kill that many more. Although habitat destruction is certainly not assisting in the perpetuation of the species, it is certainly not the biggest obstacle that the Chinese giant salamander faces in its quest to avoid extinction.^[7]

Climate change

The Chinese giant salamander is native to China, as the name suggests. It is found in Central China as well as South and Southwest China. However, its range has become fragmented as a result of a decline in total population. The Chinese giant salamander inhabits lakes with fast-running water and rocky mountain streams. These creatures spend their entire lives in water and prefer altitudes between 300m and 800m above sea level. Many can be found in the tributaries of the Pearl, Yellow and Yangtze rivers.

The Chinese giant salamander is declining in population. This is believed to be the result of a few major factors. The primary reason for their decreasing numbers is the catch rates of these creatures. Populations are not only fragmented but generally smaller in size because of the over-collection of the larger salamanders.

Like other amphibians, the Chinese giant salamander is cold-blooded. Because of their geography, there is no evidence that the climate has had an impact on their decline in numbers. The majority of southern China falls into the humid subtropical climate category. As a result, torpor has never been an issue for these creatures. The only thing severely threatening their existence is humans. Other amphibians who are endangered are experiencing such rapid declines in population due to a result of habitat destruction, over-harvesting and other mysterious reasons.^[23] Chytridiomycosis, a fungal disease, is one of these mysterious threats to the Chinese giant salamander. This disease is more common in cooler habitats usually undergoing a drought.^[23]

Overhunting

Many different amphibian species in China have been placed under threat by the International Union for Conservation of Nature or the IUCN. One of the main reasons that the Chinese giant salamander, Andrias davidianus, has been placed on the critically endangered list is the overhunting of the amphibian. In 1989, the Chinese government placed legal protection on the salamander, but for the next 15 years it continued to decline. Overall, amphibians worldwide are declining in population for many reasons, especially in China, where 84% of species of amphibians are being affected in some way by overhunting even while attempts to conserve them are being made. The Chinese giant salamander is a main example of one of these amphibians that have been in this type of decline primarily due to over-harvesting, which has great effects on the species' diversity and the conservation efforts. Overhunting overall in China is a major threat to all species in the country. In China specifically, 75% of native species in China are harvested for food. The salamander is also used for its traditional use for medicinal purposes. The demand for the use for these creatures as food in China greatly exceeds the number that can be harvested from the wild. Commercial captive breeding is looking to be the future for providing this demand to the Chinese people, but this will also have little impact on the over-harvesting threat. The profits made from the hunting and selling of the salamander will keep it as a lucrative business venture for poachers. The Chinese giant salamander also has a great value for scientists due to research possibilities for phylogenetic and physiological aspects.

China’s penalty for illegally hunting these creatures is also very low and only comes to 50 yuan, which translates to US$6. The value of these salamanders is much more than that. Salamanders are worth $100 to $150 per kg. Illegally caught salamanders are then distributed and sold to establishments such as restaurants which then charge $250–$400 per kg. These only encourage the hunting of these endangered salamanders and is the primary reason why stopping the hunting of these creatures is so challenging. A hunting tool known as a bow hook is one of the preferred methods used by hunters to catch the salamander. This hunting tool is made with a combination of bamboo and sharp hooks baited with frogs or smaller fish. This is used to capture the salamander and keep it alive. Some hunters use pesticides to kill the salamander. The population has since been assigned category II due to its population decline by The Wild Animal Protection Law of China and Appendix I in the Convention of Endangered Species of Wild Fauna.^[24][25][26]

Conservation efforts

To understand the conservation efforts in China, it is important to know something about the events of the several past hundred years of China’s history relating to social attitudes, pressures on natures and natural resources, and the political ambition to safeguard the natural environment. Each of these are significant factors and determinants of conservation efforts. Up until the year 1700, China was a country that was rampant with land reclamations, growing land exploitation, and wars. These series of events led to a huge upsurge in the diminishing of the natural biomass and as well as a reduction in spatial distribution of biotic resources. The significance of this situation was that this drastic dwindling of resources made the people of this region aware of the relationship between utilization and conservation. They then understood that there were going to be environmental consequences for their actions, yet the nation continued on their destructive path even up to the year 1910. By then many more species had gone extinct, such as the crocodile (Crocodylus porosus) and the wild camel (Camelus bactrianus). From 1911 to 1949, China began to move into the direction of modern industry, urbanization, civil wars, and agriculture. This transition period brought with it the depletion and disappearance of various renewable resources, as well as the pollution of various biotopes. This lack of conservation eventually led to a deteriorating environment, which meant lower standards of living for the Chinese human population. This is the point when both the government and the people of China came to the epiphany that the environment matters. It was not until 1956 that modern nature conservation efforts begin to develop.

The Chinese reforms that preceded this new Chinese perspective on conservation were not only beneficial to the Chinese giant salamander, but all organisms that occupied the natural environment of China. There was a formation of a new administrative system for nature conservation, which came together in the late 1950s. This new structure was able to establish new regulations that aimed at being successful in educating the masses about the value and significance of nature conservation, promoting awareness on the present status of various species, as well as prohibiting anti-conservation efforts such as hunting and trading of protected species such as the Chinese giant salamander. Some examples would be the Environmental Protection Law of 1979, Regulation of Water and Soil Conservation of 1982, Forestry Law of 1985, as well as the Wildlife Conservation Law of 1988. It was during this time period that the Chinese giant salamander was categorized as a category II species. All these species are endangered because their population is declining or their geographic distribution is becoming restricted.

In the midst of all these conservation efforts being conducted, in the late 1970s, a programme network of nature reserves was established in China. These reserves were established to uphold four major principles. First, is to conserve typical ecosystems and to represent the biotic communities. Second, the reserves are meant to secure rare, endemic and valuable species, as well as their habitats or breeding locations. Third, these reserves were developed to rescue and regenerate deteriorated or damaged natural ecosystems and habitats of special significance. Finally, the reserves would be created in order to have sanctuaries in areas of special importance, such as seed forests, geological sections, glacial remains, watershed forest, etc. Many of these reservations were created for the overall protection of all endangered species of China and the conservation of the natural world they occupy. A few more reservations were made specifically with the idea of preserving Chinese giant salamander populations. Beginning in the 1980s, there have been more than 14 nature reserves established for the conservation of the Chinese giant salamander. Examples would be the Zhangjiaje Giant Salamander Nature Reserve, Lushi Giant Salamander Nature Reserve, Qingyaoshan Giant Salamander Nature Reserve, Youyang Giant Salamander Nature Reserve, and the Taibai Giant Salamander Nature Reserve.

Though many efforts have been put forward, very few regulations have been actually been enforced. Due to lack of strong influential regulations and lack of funding, the conservation of the Chinese giant salamander has all but failed. They continue to have major decline in their populations due to human intervention of many different sorts. Even nature reserves continue to see diminution of populations. Many of the reserves suffer from the same issues, such as shortage of funding and personnel, poaching, development of tourism, etc. Few believe that even with the major losses already suffered, things can still be turned around through proper protection of the Chinese giant salamander habitats, nesting sites, prevention of pollution from run-off, banning of certain hunting methods, and an assessment of irrigation work with nature reserves. Some believe that there also need to be more surveys carried out that institutes the conservation status and demography of the salamander, as well as having a holistic view of the life history of this species. Others say that a public information campaign is needed to better educate local inhabitants.^{[27] [28] [29]}

Construction has begun on the largest artificial breeding and protection base for the endangered giant salamander in China. The base in Jing'an County, in the eastern province of Jiangxi, will breed the amphibians for scientific research, the traditional Chinese medicine industry and for exhibition in aquariums. Located in the Sanzhaolun Forest Park, the 10.83 million yuan (1.35 million U.S. dollars) project is intended to breed 60,000 giant salamanders annually when it is completed by the end of next year. The base, covering 10,000 square meters, would boost efforts to save the world's largest amphibian from extinction, said Li Xinfa, head of the Jing'an County Giant Salamander Research Center. The number of wild giant salamanders has declined rapidly due to their value as a source of traditional Chinese medicine ingredients and as food, and due to poaching, loss of habitat and pollution. It has been put on the list of the Convention on International Trade in Endangered Species, and it is under state protection in China. EDGE (Evolutionarily Distinct & Globally Endangered) aims to ensure the future of this salamander by helping to create an environmental education programme encouraging sustainable management of wild populations.

References

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