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Giant African Land Snail | |
|---|---|
| Invasive Status | |
| Highly invasive | Population increasing |
| Natural Range | |
| |
| Introduced Range | |
| |
| Pathways | |
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Pet trade Accidental shipping Food and medicinal farming | |
| Impacts | |
|
Ingestion of and damage to crops Carrying and transfer of pathogens Deterrance of tourists Ingestion of native species | |
| Removal Methods | |
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Molluscicides Collection and crushing/drowning | |
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The giant African land snail (Achatina fulica), known also as the giant African snail, is a large terrestrial gastropod which often reaches between 10 and 20 centimetres long. They are popular as pets and reproduce very quickly.
Range[]
Native Range[]
The giant African land snail is native to east Africa, especially Kenya and Tanzania. [1]
Introduced Range[]
The giant African land snail has a near-global introduced range. [2]
In Asia, the snail is present in much of the south-east. It can be found in India, Sri Lanka, Bangladesh, south and south-east China, Taiwan, Japan (Ryukyu Islands only), Myanmar, Thailand, Vietnam, the Phillipines, Cambodia, Malaysia, Brunei, Singapore and Indonesia (in Java, West Papua and Kalimantan). [2]
In Oceania, the snail is present in Papua New Guinea, the Federal States of Micronesia, the Northern Mariana Islands, Guam, Palau, the Marshall Islands, the Solomon Islands, Vanautu, New Caledonia, Wallis and Futuna Islands, Samoa, American Samoa and French Polynesia. [2]
In Africa, the snail's native continent, its introduced range runs through Cote d'Ivoire, Togo, Nigeria, Central African Republic, Madagascar, Mauritius and Réunion. [2] They are also present in Ethiopia, Somalia and Mozambique. [1]
In North America, the giant African land snail is established only in the USA, in Florida and off the mainland in Hawaii. In the Caribbean, the snail is present in the US Virgin islands, Anguilla, Antigua and Barbuda (although it is being eradicated there), Guadaloupe, Dominica, Martinique, Saint Lucia, Barbados, Trinidad and Tobego and the Netherlands Antilles. [2]
In South America, the giant African land snail is present in Colombia, Venezuela, throughout Brazil, Ecuador, Peru, Bolivia, Paraguay and northern Argentina. [2]
Pathways and Introduction[]
The giant African land snail is recorded as spreading into Ethiopia, Somalia, Mozambique and Madagascar during the 1800s. The first sighting outside of Africa was in Bengal, India in 1847. Since then it has spread massively. The giant African land snail is a popular pet and owners often underestimate how quickly the snails proliferate. The pet trade is the most substantial pathway for the snails. [1]
The snails have been intercepted on arrival in USA several times after being shipped in for the pet trade or with plants. In 1958 and again in 1966 snails were brought to USA from Hawaii and released. The latter introduction was to Florida and the snails became established (with the population reaching 18,000 animals***). Though successful, the task of eliminating the snails cost over a million dollars and took over a decade. [1/3]
These snails are also sometimes introduced for food and medicinal use. They also occassionally hitchhike unseen on vehicles and are moved in garden waste. [4]
Impacts[]
The giant African land snail is a major agricultural pest, targeting crops such as breadfruit, cassava, cocoa, papaya, peanut and rubber plants and many others besides. [2] The snails are capable of eating over 500 different plant species. [1]
The snails also carry the rat lungworm parasite and can transfer it to humans when eaten, causing eosinophilic meningitus. They can also carry the bacterium aeromonas hydrophila which can cause a wide variety of symptoms. [1]
The snails can also put off tourists, since they may be considered unsightly to some and thrive in the warm tropical areas which are often popular for tourists.* The bodies of deceased snails are also smelly and unsettling where the snail is present in large numbers. [2]
Giant African land snails also eat native plant species and may outcompete native gastropods. [2]
Control and Removal Methods[]
Mollucicides are often used against giant African land snails, with metaldehyde being the most popular and effective ingredient. However, use of these chemicals also negatively impact native species. Iron phosphate is also used with reduced effects on native species. [1]
The rosy wolfsnail and Gonaxis kibwiensis have previously been used as biological controls but have themselves become invasive. The planarian worm Platydemus manokwari has been used with more succcess, although it too could become invasive and so, since so little is known of its ecology, its use is discouraged. [2]
Collection of the snails and use of salt, crusing or drowning to kill them is also often used over a smaller scale. [2]
Sources[]
1 Columbia.edu Introduced Species Summary Project