South American apple snails (Pomacea insularum & P. canaliculata)
Members of the freshwater snail family Ampullariidae, known as apple snails.
This family has an impressive track record for becoming invasive.
Channeled Apple Snail (Pomacea canaliculata) has been designated one of the Top 100 Globally Invasive Alien Species by the ISSG.
The Island Apple Snail (Pomacea insularum) is difficult to distinguish from P. canaliculata.
Large snails (up to 10cm) with bright pink egg clusters and a shell with 5-6 whorls separated by a deep, indented suture, hence “channeled” apple snail.
Not to be confused with the smaller, beneficial, native snail, the Florida Apple Snail (Pomacea paludosa).
Native to Rio Parana, north of Buenos Aires, Argentina.
Major pest in 18 counties, including the U.S.
Voracious herbivore with a wide menu (rice seedlings, taro, duck weed, water hyacinth, algae, azolla, and other succulent leafy plants). Prefers young, soft plants, but will clip mature, rooted plants at the soil surface.
Will eat eggs and juveniles of other snails and will also eat decomposing organic matter.
Can detect food at a distance using chemical cues.
Densities of over 130 snails/ m2 have been observed in Taro fields in Hawaii and up to 150 snails/ m2 have been reported in the Philippine rice paddies.
Introduced into Texas by 1989, in Florida by the mid-90’s, in Georgia by 2005, and recently discovered in Louisiana, Alabama, and South Carolina.
Potential to spread throughout the entire Southern Coastal Plain in the U.S. from Texas to South Carolina.
Represents a major risk to native wetland and aquatic systems and to agriculture in the Southeast U.S.
Has become a devastating agricultural pest in Southeast Asia, especially of rice.
Destroyed native aquatic vegetation in Thailand leading to serious habitat modification.
Greatly reduced Taro production in Hawaii
Competitive interactions with native aquatic fauna, especially native snails.
Following its introduction into Florida waterbodies, there is an apparent disappearance of the native apple snail.
Potential for extinction by hybridization of the native Florida Apple Snail.
Intermediate host of important vertebrate parasites, most notably the Rat Lung Worm (Parastrongylus cantonensis).
Amphibious but mostly aquatic
Can bury in the bottom sediments of up to 5 months and survive periods of extreme low water.
Every 12-15 days, females lay bright pink clutches of 25-500 eggs, usually 200-300 eggs.
The eggs hatch in 10-15 days.
Snails can reach maturity 60-85 days after hatching.
One female can produce up to 15,000 offspring per year.
About Snail Busters
The Snail Busters Blog was created to facilitate communication between aquatic resource managers who are fighting the spread of invasive, South American apple snails, specifically Pomacea maculata (formerly P. insularum) and P. canaliculata, in the U.S.