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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.




Pomacea maculata
Pomacea maculata
(giant applesnail)
Mollusks-Gastropods
Exotic
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Pomacea maculata Perry 1810

Common name: giant applesnail

Synonyms and Other Names: Ampullaria insularum, Ampullaria gigas, Pomacea insularum

Identification: Typical applesnails are globular in shape. Normal coloration typically includes bands of brown, black, and yellowish-tan, and color patterns are extremely variable. Albino and gold color variations exist (R. Howells, pers. comm.).

Size: Can reach 155 mm in shell height (Pain, 1960 as cited in Cowie, 2002)

Native Range: Throughout much of tropical and subtropical South America (Hayes et al., 2012).

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Alaska
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Hawaii
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Puerto Rico &
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Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Pomacea maculata are found here.

StateYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Alabama200320082Escatawpa; Mobile-Tensaw
Arizona201120111Lower Salt
Florida1989201733Alafia; Apalachee Bay-St. Marks; Big Cypress Swamp; Caloosahatchee; Cape Canaveral; Charlotte Harbor; Chipola; Crystal-Pithlachascotee; Daytona-St. Augustine; Everglades; Florida Southeast Coast; Hillsborough; Kissimmee; Little Manatee; Lower Ochlockonee; Lower St. Johns; Manatee; Myakka; Northern Okeechobee Inflow; Ochlockonee; Oklawaha; Peace; Pensacola Bay; Santa Fe; Sarasota Bay; St. Andrew-St. Joseph Bays; St. Marys; Tampa Bay; Upper St. Johns; Upper Suwannee; Vero Beach; Withlacoochee; Withlacoochee
Georgia200520157Cumberland-St. Simons; Lower Flint; Lower Savannah; Satilla; St. Marys; Upper Ochlockonee; Withlacoochee
Louisiana2006201813Amite; Atchafalaya; Bayou Teche; Calcasieu-Mermentau; East Central Louisiana Coastal; Eastern Louisiana Coastal; Lake Maurepas; Liberty Bayou-Tchefuncta; Lower Grand; Lower Pearl; Mermentau; Vermilion; West Central Louisiana Coastal
Mississippi200820143Lower Pearl; Mississippi Coastal; Pascagoula
Puerto Rico200620092Eastern Puerto Rico; Southern Puerto Rico
South Carolina200820174Bulls Bay; Cooper; Middle Savannah; Waccamaw
Texas200020177Austin-Oyster; Buffalo-San Jacinto; Lower Brazos; Lower Trinity; Lower West Fork Trinity; Spring; West Galveston Bay

Table last updated 6/23/2018

† Populations may not be currently present.


Ecology: This large snail is found in freshwater lakes, rivers, streams, ponds and ditches, preferring slow-moving water. Applesnails are tropical to subtropical organisms and cannot survive below 50°F in the winter (Florida DOACS, 2002).

The sexes are separate and fertilization is internal (Andrews, 1964). Bright pink egg masses are laid on emergent vegetation or manmade structures above the water. They are held in place when the secreted mucous dries (Andrews, 1964). Individual eggs are very small, approximately 1-2 millimeter in diameter. An egg mass may contain over 2000 eggs (Barnes et al., 2008). May reach 6 inches in shell height and is considered the largest snail on earth (Florida DOACS, 2002).

The only terrestrial predator that has been observed capturing and eating apple snails is raccoon (Procyon lotor) (Carter et al. 2017).

Means of Introduction: Pomacea maculata is in the pet trade, and can be introduced by aquarium dumps (Florida DOACS, 2002). There is also evidence that the snail can be transported by flood waters (Advocate staff report 2018).

Status: Established in Florida, Georgia, Texas (Rawlings et al. 2007) and Louisiana, and most likely where there is evidence of egg masses, often first noticed prior to adults.

Impact of Introduction: Applesnails are known agricultural pests, feeding on rice crops and causing great economic damage (Cowie, 2002; Hayes et al., 2008). This species has been known to be a carrier of the rat lungworm parasite in New Orleans and Mandeville, Louisiana populations, but it is not widespread in the applesnail population (J. Teem, pers. comm.).  Cattau et al. (2017) found that a predator of P. maculata, a snail kite (Rostrhamus sociabilis), has an increased bill size in response to the larger than normal prey size when compared to the native applesnail.

In 2018, an Acadia Parish, LA farmer had to shut down his crawfish harvest due to applesnails that had entered his rice fields when it was flooded with water from a bayou that flows into the Mermentau River (Advocate staff report 2018).

Remarks: Initially P. insularum had been identified as P. canaliculata in Florida, Georgia, and Texas. Genetic testing confirmed that specimens collected in Florida, Georgia, and Texas were P. insularum (Rawlings et al. 2007). Since then, P. insularum has been synonomized with P. maculata (Hayes et al., 2012).

Research by Savaya-Alkalay et al. (2018) suggests that the development of all-male prawn populations of Macrobrachium rosenbergii has the potential as a biocontrol agent over hatchling and adult apple snails (Pomacea spp.). Medium-sized and large prawns (10–30 g) efficiently preyed on snails up to 15mm in size, while small prawns (up to 4 g) effectively consumed snail hatchlings.

References: (click for full references)

Advocate staff report. 2018. Invasive snail found in Acadiana crawfish pond; pest also poses threat to rice plants. The Acadiana Advocate. Baton Rouge, LA. http://www.theadvocate.com/acadiana/news/article_a44e0de0-1039-11e8-ab97-efed1305c5da.html. Created on 02/12/2018. Accessed on 02/13/2018.

Andrews, E.B. 1964. The functional anatomy and histology of the reproductive system of some Pilid gastropod molluscs. Journal of Molluscan Studies 36(2):121-140.

Barnes, M.A., R.K. Fordham, R.L. Burks, and J.J. Hand. 2008. Fecundity of the exotic applesnail, Pomacea insularum. Journal of the North American Benthological Society 27(3):738-745.

Carter, J., S. Merino, D. Prejean, and G. LaFleur, Jr. 2017. Observations of raccoon (Procyon lotor) predation on the invasive Maculata apple snail (Pomacea maculata) in southern Louisiana. Southeastern Naturalist 16(3):N14-N18.

Cattau, C.E., R.J. Fletcher, Jr., R.T. Kimball, C.W. Miller, and W.M. Kitchens. 2017. Rapid morphological change of a top predator with invasion of a novel prey. Ecology and Evolution DOI:10.1038/s41559-017-0378-1, 10 pp.

Conner, L. Personal communication. Florida Fish and Wildlife Conservation Commission.

Cowie, R.H. 2002. Apple snails (Ampullariidae) as agricultural pests: their biology, impacts and management. Pages 145-192 in Barker, G.M., ed. Molluscs as Crop Pests. CABI Publishing, Wallingford, UK.

Denson, D. Personal communication. Florida Department of Environmental Protection.

Florida FDOACS. 2002. Applesnails. Technical Bulletin Number 3, 4 p. Accessed 6/28/2012 at http://edocs.dlis.state.fl.us/fldocs/doacs/aquaculture/techbull/2002no3.pdf

Grana, F. Personal communication. Puerto Rico Department of Natural and Environmental Resources.

Hayes, K.A., R.H. Cowie, S.C. Thiengo, and E.E. Strong. 2012. Comparing apples with apples: clarifying the identities of two highly invasive Neotropical Ampullaridae (Caenogastropoda). Zoological Journal of the Linnean Society 166(4):723-753.

Hayes, K.A., R.C. Joshi, S.C. Thiengo, and R.H. Cowie. 2008. Out of South America: multiple origins of non-native apple snails in Asia. Diversity and Distributions 14(4):701-712.

Howells, R. Personal communication. Texas Parks and Wildlife Department.

Howells, R. G. 2001. History and status of applesnail (Pomacea spp.) introductions in Texas. Texas Parks and Wildlife Department, Management Data Series No. 183.

Pain, T. 1960. Pomacea (Ampullariidae) of the Amazon River system. Journal of Conchology 24: 421-432.

Rawlings, T. A., K. A. Hayes, R. H. Cowie, and T. M. Collins. 2007. The identity, distribution, and impacts on non-native apple snails in the continental United States. BMC Evolutionary Biology, http://www.biomedcentral.com/1471-2148/7/97.

Savaya-Alkalay, A., Ovadia, O., Barki, A., and A. Sagi. 2018. Size-selective predation by all-male prawns: implications for sustainable biocontrol of snail invasions. Biological Invasions 20:137–149.

Shelton, D. Personal communication. Alabama Malacological Research Center.

Teem, J. Personal communication. Florida Dept. of Agriculture and Consumer Services.

Author: Benson, A.J.

Revision Date: 2/16/2018

Citation Information:
Benson, A.J., 2018, Pomacea maculata Perry 1810: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2633, Revision Date: 2/16/2018, Access Date: 7/16/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [7/16/2018].

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