The Salt Marsh Snail is an introduced European species that is found along the west coast of North America from British Columbia south to Baja California, Mexico (Forsyth 2011). It occurs along the edge of salt marshes, on plant stems and under debris (
Cohen 2005). In BC, it is reported from the southern part of the coast, with collections from Boundary Bay, Esquimalt Lagoon in Victoria, and on South Pender Island.
Cohen (2005) discusses its arrival on the Pacific Coast: "The first record of Myosotella myosotis on the Pacific Coast is from San Francisco Bay in 1871, followed by Humboldt Bay in 1876. It probably arrived on the Pacific Coast in transcontinental shipments of Atlantic oysters (Crassostrea virginica), which started in 1869, though possibly it might have come in solid ballast or, less likely, in hull fouling. Its appearance in other Pacific Coast sites could have derived in some cases from transplants of oysters along the coast, or from transport in solid ballast or hull fouling on coastal vessels, or possibly from separate introductions from the Atlantic. Since Myosotella myosotis does not have planktonic larvae, it is unlikely to have been transported in ships' ballast water."
