The New Zealand Mudsnail is a tiny gray to brown species of freshwater snail that is native to New Zealand and adjacent small islands, and is introduced and invasive in North America (Benson and Kipp 2011
). It was discovered in the US in 1987 in Idaho, and in British Columbia in Port Alberni in 2008 (BCCDC 2010
, USGS 2011
This species is tolerant of fresh and brackish water (salinity up to 26%) (BCCDC 2011, Benson and Kipp 2011). Benson and Kipp (2011) discusses species ecology: "The snail tolerates siltation, thrives in disturbed watersheds, and benefits from high nutrient flows allowing for filamentous green algae growth. It occurs amongst macrophytes and prefers littoral zones in lakes or slow streams with silt and organic matter substrates, but tolerates high flow environments where it can burrow into the sediment". It can also tolerate a wide range of temperatures (USGS 2011).
The New Zealand Mudsnail has a high reproductive capacity: it is ovoviviparous or populations may be entirely parthenogenic--all populations from the western US are comprised of parthenogenic females, and can produce young throughout the year (BCCDC 2011, USGS 2011). .Dispersal is passive, via birds or fish, and floating plants (BCCDC 2011, Benson and Kipp 2011).
Read the USGS fact sheet, and view photos and a distribution map for the United States.
Read the US Army Corps of Engineers fact sheet on this species.