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Closeup of New Zealand Mudsnails
  • Native to New Zealand

  • Arrived in ship ballast water

New Zealand Mudsnails

New Zealand mudsnail
(Potamopyrgus antipodarum)

New Zealand mudsnails range in size from a grain of sand to 6 mm long.  They have 5 or 6 whorls.  They range in colour from grey to dark brown.  They can reach extremely high densities, up to 300,000 per square meter have been recorded.  It only takes one female to start a colony.  They are self-reproducing and bear live, well developed clones.

New Zealand mudsnails would have the biggest impact on anglers.  They alter aquatic habitats and food webs by eating algae and competing with native bottom-dwelling organisms.  By altering the ecosystem they reduce native trout and other recreational fisheries.

New Zealand mudsnails spread mainly attached to waders, fishing gear, and bait.  They can survive for days out of water so it is important to Clean Drain Dry.

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