||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