Distribution of Potamopyrgus antipodarum

Potamopyrgus antipodarum is endemic to New Zealand. It lives in freshwater streams and lakes of New Zealand and adjacent small islands. However while endemic to New Zealand, it has spread widely and had become naturalized in other parts of the world. Today NZMS is found around the globe in various water bodies and its abilities to invade new territories make this snail serious treat for native ecosystem.

No indigenous distribution
New Zealand mud snail has spread widely as an invasive species in Australia, Tasmania, Asia (Japan ( Davidson et all 2008), in Garmat Ali River in Iraq since 2008 (Naser and Son 2009), Europe since 1859 in England, and North America (USA and Canada: Thunder Bay in Ontario since 2001, British Columbia since July 2007( Davidson et all 2008), most likely due to inadvertent human intervention.

European countries invited by P. antipodarum
Potamopyrgus antipodarum occurs in nearly the whole of Europe. Currently we do not know any confirmed locations of NZMS in Iceland, Albania, Bulgaria and the former Yugoslavia (Son 2008)
A country in Europe that P. antipodarum was reported in the past:

• England since 1859 Čejka et al 2008 - probably the first introduction in Europe
• Germany
• Poland
• Western Baltic Sea since 1887 (Filippenko & Son 2008)
• Russia
• Azov Black Sea region, since 1951(Son 2008), Ukraine since 1951 in brackish waters, and since 2005 in freshwater (Alexandrov et al 2007)
• Catalonia in Spain, since 1952 (Radea et al 2008)
• Mediterranean region of France, since the end of 1950s (Radea et al 2008)
• Italy, since 1961(Radea et al 2008)
• Turkey(Radea et al 2008)
• Czech Republic, since September 3 1981(Kuchař)
• Slovakia, since 1986
• Greece, since November 2007 (Radea et al 2008)

To see maps of recent distribution of New Zealand Mud Snails in United States with emphasis on  South West region of US please visit our map sites

USA
California
Arizona
Nevada

 P. antipodarum is now reported from North America:  Canada (Port Alberni, British Columbia), all western states of United States, ( with exception of New Mexico), and in Great Lakes in eastern part of US.

The pattern of NZMS invasion involves geographic jumps, which supports the theory of introduction to new sites from various vectors and not under its own volition since we don’t observe a smooth and steady invasion front. The spread of NZMS into new systems is believed to be mostly caused by humans, with the most common dispersal methods being hatchery transplants, contaminated fishing equipment, boats, and trailers (Richards 2002). Other possible vectors of introduction could include wading anglers moving between sites, rafters and kayakers floating between river access points, fishery biologists sampling various sites, etc. Additionally, some authors reported spread by waterfowl (Lassen 1978 in Richards 2002), fish and discarded aquarium plants and pets as being other possible vectors.