A Review

The Invasion of the Alien Species Alligator Gar (Atractosteus spatula) All over China  

Yeping Han
Ecological And Evolutionary Research Team, Cuixi Academy of Biotechnology, Zhuji, 311800, China
Author    Correspondence author
International Journal of Molecular Ecology and Conservation, 2022, Vol. 12, No. 1   doi: 10.5376/ijmec.2022.12.0001
Received: 27 Aug., 2022    Accepted: 28 Aug., 2022    Published: 31 Aug., 2022
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Preferred citation for this article:

Han Y.P., 2022, The invasion of the alien species alligator gar (Atractosteus spatula) all over China, International Journal of Molecular Ecology and Conservation, 12(1): 1-6 (doi: 10.5376/ijmec.2022.12.0001)

Abstract

This study elucidated the origin of the alligator gar (Atractosteus spatula) by investigating the traces of the alligator gars in various waters in different provinces and cities of China. Alligator gars originally entered China through ornamental fish trade (illegal smuggling). They are abandoned by people probably because it is difficult to raise them, or released by people out of "goodwill". Therefore, the invasion sites of alligator gars are mainly concentrated in the waters of the residential districts and the lakes of the parks. The invasion of alligator gars has brought potential threats to the aquatic ecosystem in China. Through reading the literature and regulations, this study found that alligator gars are not included in the list of alien invasive species at present. However, according to the overwintering ability and damage degree of alligator gars, some experts have suggested that it should be included in the list of alien invasive species. This study also put forward its own views on the proper treatment of the alien species alligator gars.

Keywords
Alligator Gar (Atractosteus spatula); Alien species

Alligator gar (Atractosteus spatula), also known as Fu-e and Da-que-shan in Chinese, is a prehistoric fish. It is an animal of Antipodocottus genus in the family of Lepisosteidae in Lepisosteiformes, which has lived on the earth for more than 100 million years. It is the largest of the seven existing species of North American gars. It is named after its short snout and two rows of sharp teeth like a crocodile. It is mainly distributed in the southeast coastal area of the United States, west to Texas and Oklahoma, north to the Mississippi River Basin, the lower reaches of the Ohio River and the Missouri River Basin, and south to Mexico. There are no alligator gars in China, which are alien species.

 

Alligator gar is a carnivorous fish, and it is very fierce in nature. It will prey on Chinese native species, especially fish in the water area, which may cause the break of food chain. The algae, food of fish, will also be flooded in large areas. These aquatic plants will form the advantage of a single species in the water area, and will cause ecological disasters in a certain range. In addition, this alien species lacks natural enemies, and all fish in the water area will be eaten. If there is a shortage of food, the alligator gars will even attack humans, which may cause personal injury. Not only that, the eggs of alligator gars are highly toxic. For nearly a half century, alligator gars were considered as “trash fish” (Brady and Tony, 2013) or a “nuisance species” (Echevarria and Carlos, 2013).

 

1 Report on the Traces of Alligator Gars in China

1.1 Henan

In mid July 2022, alligator gars appeared in Yunchan Lake, Central Park of Ruzhou City, Pingdingshan, Henan, which caused the local government to attach great importance to it. They immediately organized a salvage team to catch and salvage it, and searched it through sonar system positioning, but it did not work. On the evening of August 26, it took nearly one month to pump out about 300 000 cubic meters of lake water, two alligator gars (Figure 1) were successfully captured finally, one of which was about 0.9 meters long and the other was about 0.7 meters long. This event also immediately attracted extensive attention from people to the alien species “alligator gar”.

 


Figure 1 The scene of capturing alligator gars in Ruzhou, He’nan (picture from the Internet)

 

1.2 Shandong

Alligator gars also appeared in an artificial lake in a residential district on the west coast of Qingdao, Shandong. All kinds of fish in the lake were basically eaten up by alligator gars. Then, the water in the artificial lake was completely drained. As the alligator gars is flexible in the water and swims fast, and it hid at the bottom of the wooden plank road, the catching personnel failed to catch it on August 26. On August 27, the pumping operation of the artificial lake was basically completed, and the catching personnel successfully captured two alligator gars. Among them, the larger one was more than 1 meter long and weighed 13 kilograms. At present, there are still alligator gars in the lake that have not been captured. The local government and the catching personnel have concentrated their efforts, and the capturing is still in progress.

 

1.3 Yunnan

In Kunming, Yunnan, an alligator gar also appeared in the observation pool of a residential district. With its appearance, other fish and shrimp in the pool disappeared. On August 26, the staff of the residential district drained the water in the observation pool through the pump and successfully captured the alligator gar (Figure 2). At present, the Kunming Bureau of Agriculture and Rural Affairs has set up an expert group to investigate the alligator gars in Kunming.

 


Figure 2 The scene of capturing alligator gars in Kunming, Yunnan (picture from the Internet)

 

1.4 Hunan

On the afternoon of August 26, the Disease Prevention and Control Center for Animals and Plants in Changsha of Hunan received a phone call saying that a resident caught a “strange fish” in Yuelu District, whose long mouth was somewhat similar to that of a crocodile. According to expert identification, this “strange fish” that first appeared in Hunan is “alligator gar” (Figure 3).

 


Figure 3 The scene of identifying the alligator gar in Changsha, Hu’nan (picture from the Internet)

 

1.5 Jiangsu

On August 17, a child in Taizhou, Jiangsu, was bitten by a “strange fish” when he was playing with water by the landscape pool in a residential district. Then, the staff and residents of the residential district drained the landscape pool and caught it. The “strange fish” that hurt people was the alligator gar, which was 0.7 meters long and weighed more than 5 kilograms.

 

1.6 Beijing

On July 28, a resident of a residential district in Beijing picked up a large fish from the water system of the residential district, which was confirmed by experts as the alien species “alligator gar”. On August 5, the resident has handed over the alligator gar to the relevant departments.

 

1.7 Guangxi

On June 8, alligator gars also appeared in a pool in the Xishan Scenic Area of Guiping, Guangxi. The local fishery authorities spent two days to drain the pool and captured two large alligator gars (Figure 4), weighing 7.02 kilograms and 8.32 kilograms respectively.

 


Figure 4 The scene of capturing alligator gars in Guiping, Guangxi (picture from the Internet)

 

1.8 Fujian

On May 2, a “giant object” was reported to appear in the “Free-life Pond” in Xiamen, Fujian. Subsequently, the local residents salvaged two alligator gars, both of which were not small. One of them was 1.34 meters long and weighed about 20 kilograms (Figure 5).

 


Figure 5 The scene of capturing alligator gars in Xiamen, Fujian (picture from the Internet)

 

1.9 Sichuan

In May, an alligator gar also appeared in an artificial lake in a residential district in Zigong, Sichuan. The residents spent several hours to finally catch it. This alligator gar was about 0.8 meters long and weighed more than 5 kilograms. Its scales are as hard as a layer of armor (Figure 6).

 


Figure 6 The scene of capturing the alligator gar in Zigong, Sichuan (picture from the Internet)

 

1.10 Guangdong

As early as April, an alligator gar appeared in Xiaodehu Park in Luocun, Nanhai District, Foshan City, Guangdong Province. After more than one hour of the dawdle fish, local residents successfully fished it (Figure 7).

 


Figure 7 The scene of capturing the alligator gar in Foshan, Guangdong (picture from the Internet)

 

2 Tracing of the Reasons for the Invasion of Alligator Gars into China

There are no alligator gars in China. How did the alligator gars enter China? At present, it is generally accepted that the alligator gars were originally traded as ornamental fish (Figure 8) and entered China through illegal smuggling. The special shape of alligator gars satisfies the consumers’ curiosity. According to some reports, large alligator gar could fetch as much as $40 000 (Horswell and Cindy, 2011).

 


Figure 8 Two alligator gars in an aquarium tank (Photoed by Ye Hongmei)

 

However, the growth of alligator gars is very fast, and ordinary aquarium tanks can not support them. It is impossible for ordinary families to raise them in an aquarium tank of tens of meters. Moreover, the feeding cost of alligator gars is very high. Therefore, some alligator gars were abandoned. In addition, some “kind people” may release some creatures at will, or they may release alligator gars unintentionally.

 

From the perspective of consumption groups of alligator gars, at present, they are mainly raised by urban residents, and the above-mentioned alligator gars were also found in cities, mainly concentrated in the waters of the residential districts and the lakes of the parks. Therefore, it can be basically determined that whether abandoned or released, these alligator gars were artificially put into the natural waters.

 

The survival ability and reproduction ability of alligator gars are particularly strong, or it will continue to spread in other waters and other provinces in China. At present, departments of agriculture and rural affairs in many places have started to carry out the census of alien species, including alligator gars.

 

3 Summary and Comments

The appearance of alligator gars not only caused damage to the native species in the waters, but also attacked people. Moreover, the eggs of alligator gars are highly toxic. Therefore, we can not take it lightly. Although according to the four batches of “List of Alien Invasive Species in China” issued by the Ministry of Ecology and Environment of the PRC and “List of National Key Managed Alien Species (the First Batch)” issued by the Ministry of Agriculture of the PRC, alligator gar is not an alien invasive species, China is currently promoting the management and restoration of alien invasive species, and the list of alien invasive species is also being further updated. In 2020, the Ministry of Agriculture and Rural Affairs of the PRC called for a ban on the release or abandonment of major alien species, including alligator gars. On January 20, 2021, the Ministry of Agriculture and Rural Affairs, the Ministry of Natural Resources, the Ministry of Ecology and Environment, the General Administration of Customs, and the State Forestry Administration of the PRC jointly issued the “Notice on Printing And Distributing ‘the Work Plan for Further Strengthening the Prevention And Control of Alien Species Invasion’”, which mentioned that we should strengthen the supervision of aquatic alien species breeding, and promote the comprehensive management of aquatic alien invasive species such as water hyacinth (Eichhornia crassipes), golden apple snail (Pomacea canaliculata) and alligator gar.

 

Experts say that “alien invasive species” and “alien species” are two different concepts. Only those species that have established populations in natural waters and formed harm are alien invasive species. For example, although piranha (Pygocentrus nattereri) is an alien species, it can not be said to be an alien invasive species, because this species has no ability to survive the winter and belongs to tropical fish. It will soon lose its viability and has no harm. Therefore, it was not listed in the list of alien invasive species. However, with the deepening of scientific research and the increase of time, it has been found that it can survive the winter, reproduce and form a hazard. Now, from the scientific definition, it is an invasive species. For the alligator gar, it can survive the winter in some areas in the south, and some warmer places in the north may also. Therefore, some experts have suggested that the alligator gar should be included in the list of alien invasive species.

 

In terms of the harm of alligator gar, if it enters the aquaculture water area, it will eat the cultured fish and shrimp, while if it enters the lake, it will eat the fish and shrimp in the water. There are some subsequent hazards. If fish and shrimp are eaten, it will affect the algae in the water and the water quality. In a word, the destruction of alligator gar to aquatic ecosystem is huge, which can lead to the disappearance of some aquatic organisms. Although it is not very aggressive to people, it still poses a certain threat. “The Measures for the Management of Alien Invasive Species”, which came into effect on August 1, 2022, stipulates that targeted fishing and other measures should be taken to prevent the further spread of alien invasive aquatic animals. Therefore, if the alligator gar is found, it is best to fish it out and carry on harmless treatment.

Finally, it is worth reminding that releasing invasive species without authorization will damage the ecological balance of the local area. The relevant laws and regulations of China explicitly prohibit individuals from releasing animals without authorization. If someone violates the regulations, he/she will face a fine of relevant amount or even be investigated for criminal responsibility.

 

Acknowledgments

The research cases cited in this article are all Chinese news reports, and the pictures cited are all from the publicly released network platforms, which can not be listed in the references one by one. Here, I would like to thank the copyright owners.

 

References

Brady and Tony, 2013, Fleur de lis fisheries, US Fish & Wildlife Service, p. 2

 

Echevarria and Carlos, 2013, Alligator gar, Atractosteus spatula, warm springs national fish hatchery, US Fish & Wildlife Service, retrieved July 7, 2014

 

Horswell and Cindy, 2011, Indictments accuse 3 of taking alligator gar fish out of Trinity, Houston Chronicle

International Journal of Molecular Ecology and Conservation
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