Invasive species are making headlines in China. In August, an alligator gar, a large predatory fish, was discovered in a lake in the city of Ruzhou in Henan Province. The authorities drained the entire lake, but the fish evaded capture.
Alligator gar, an American species now found across Southern China. Image: by Jason Goh
Alligator gar is a North American species. Imported into China as an aquarium fish, it was then bred in large numbers. Escaped and released alligator gar have recently been found in rivers and lakes in Southern China.
Leading the world in invasive species
The gar are not alone. Estimates vary, but at least over 400 other species of non-native fish are thought to have invaded Chinese lakes and rivers. Guangdong Province is now home to South American suckermouth armoured catfish, and American paddlefish are now routinely caught in the Yangtze and its tributaries.
In addition to fish, China has been invaded by mammals, birds, insects, reptiles, amphibians, worms and plants, earning the distinction of being the country with the largest number of invasive species in the world. China’s vulnerability to invasive species is explained by a number of factors including its varied climates and ecosystems which make it habitable to different animals. In addition, China’s wildlife farming, aquaculture and pet industries have imported many non-native species, leading to accidental and purposeful escapes. Finally, China is the world’s largest trading nation, and many invasive species have been able to hitchhike into the country on the back of imported goods.
The official list of invasives in China contains 71 species, most of which are plants or insects. It was last updated in 2017 and contains no reptiles, mammals or birds. In contrast to the official list, the latest scientific studies estimate the number of invasive species in China at close to 700, although that is almost certainly an underestimation. Guangdong Province which neighbours the Hong Kong Special Administrative Region, holds the national record with over 400 invasive species, of which 160 are fish.
The many harms caused by invasive species are well known to conservationists. Invasive weeds and insects can spread uncontrollably, damaging and destroying crops and trees. Invasive species may carry into their new host country bacteria, viruses and parasites, putting animal and public health at risk. Finally, by replacing or feeding on native species, the invasives compromise entire ecosystems and with that, the services that these ecosystems, be they forests, grasslands or fishing grounds, provide to local people.
A 2022 study estimated that between 1960 and 2020 the total economic damage caused by invasive species of invertebrates reached almost 700 billion US dollars. Most of this damage has been done in recent years.
Star-cucumber (Sicyos angulatus), a North American species of vine that is now invasive worldwide, including China. It smothers native vegetation, forming thick mats. Image: By Pampuco https://commons.wikimedia.org/w/index.php?curid=97816885
Brazil, like China, has hundreds of invasive species, and research has shown that the minimal cost of biological invasions in Brazil over 35 years (1984–2019) amounted to 105.53 billion US dollars. Of this sum, 104.33 billion dollars was due to damages and losses caused by invasive species, with just 1.19 billion invested in prevention, control or eradication.
In China, no recent figures are available, but a 2006 estimate of the economic loss caused by invasive species suggested the sum was more 14 billion US dollars per year. This estimate is now out of date. The number of invasive species has tripled in the last ten years, and new invasive species are detected with greater and greater regularity in China.
The ongoing Covid-19 pandemic has been a wake-up call to authorities of the need for legal controls to prevent zoonosis – the transmission of animal pathogens, such as viruses and bacteria, to humans.
In October 2020, the 13th National People’s Congress of the People's Republic of China passed the passed a sweeping National Biosecurity Law (NBL) which came into force on April 15, 2021.
In addition to targeting prevention and control of outbreaks of infectious diseases in animals or plants and biosecurity management of pathogenic microbe laboratories, the NBL also addresses the introduction of non-native species and the threat these species pose to local biodiversity.
Following the introduction of the NBL, in March this year a new clause was added to article 344 of Chinese criminal code: “Illegal introduction, release or abandoning of invasive species violates national regulations; where the circumstances are severe, the punishment is up to three year imprisonment or detention and a fine.”
In 2022, the Chinese authorities also published a list of aquatic species that cannot be released into waterways. It includes not only the above-mentioned alligator gar, but also alligator turtles and red-bellied piranhas, amongst others.
List of aquatic species the release of which is prohibited in China
Public notices such as this are not just targeted at individuals who release unwanted pets into the waterways. This public notice is a response to fangsheng – a wide spread Buddhist practice where animals are released into the wild as an act of mercy. Fangsheng in China has let to mass releases of alien species of turtles, fish, invertebrates and birds, many of which have caused environmental damage. The practice is also objectively cruel, as released animals often cannot survive in their new environment, and die starving or being eaten by predators.
Hong Kong – an invasion route into Mainland China
Despite the Convention on Biological Diversity being extended to Hong Kong in 2013, the SAR made no changes to its legislation to control the introduction of invasive species. Hong Kong is a wildlife trading hub and many exotic species are legally and illegally imported to the SAR for the food and pet trade.
Hong Kong is one of the main routes for invasive species into Mainland China. A 2017 study found that 22 of the 127 top invasive species in China were first detected in Hong Kong. Moreover, confirming that Hong Kong is a stepping stone for species into Mainland China – the regions and provinces of China located closer to Hong Kong contained larger numbers of invasive species that had been first detected in Hong Kong.
A recent study found 25 species of non-native freshwater turtles living in Hong Kong. This number is exceptionally high for an area of the small size of Hong Kong. The turtles are likely to have released as abandoned pets or in religious releases – fangsheng.