NAS logo - click to go to the NAS home page Mollusks (Phylum Mollusca) are found in marine, brackish, and fresh waters. They include a diverse group of animals such as clams, mussels, oysters, scallops, abalone, conchs, shipworms, snails, nudibranchs, chitons, squids, and octopuses. Common methods of introduction include ballast water introductions, aquarium releases, and accidental release from aquaculture facilities. Displacement by competition is the most frequently observed impact on native species. The most notable nonindigenous mussel introduction is the zebra mussel (Dreissena polymorpha), a native of eastern Europe.
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Data Queries and Species Lists

mudsnail Picture Data Queries
Species List of Nonindigenous Mollusks
(links to species profiles and collection information)
New Zealand Mudsnail Distribution

Zebra and Quagga Mussel Information

zebra mussel picture Zebra and Quagga Mussel Home Page

Links to News and Other Information

Museum Collections Systematic Research Collections: Mollusca Illinois Natural History Survey
Invertebrate Zoology Collections at The Smithsonian Institution
University of Michigan Mollusk Division


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. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [6/21/2024].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted.

For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.