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Mollusc

ANS—Mollusc

Zebra Mussel

Description

Zebra Mussel. Zebra Mussel
  • Dreissena polymorpha
  • Has caused profound ecological changes in freshwater ecosystems where it is established, including losses of phytoplankton and microzooplankton
  • Causes mortality of native clams and mussels
  • Cost municipal and industrial water facilities millions of dollars to control
  • If introduced into Montana will likely survive, become established and result in significant environmental and industrial damage
  • Transported overland in bilges, livewells, motors and attached to boats and trailers

General Characteristics

  • larvae not possible to see with naked eye
  • newly settled larvae feel like sand paper on smooth surfaces
  • juveniles are pepper corn size
  • mussel with brown to black stripes
  • adults can grow up to 2" long, typically are ¾" long

Links

In October 2013, the Manitoba government issued a news release reporting the first detection of zebra mussels in the province, and the furthest west reported mussels in Canada. Lake Winnipeg is the 10th largest freshwater lake in the world.


New Zealand Mudsnail

Description

New Zealand Mudsnail Map. New Zealand Mudsnail Distribution Map (USGS)

New Zealand Mudsnail. Key shows the size of New Zealand Mudsnails.
  • Potamopyrgus antipodarum
  • Spread via stocking operations, by recreational anglers, or possibly aquarium release
  • Reproduces asexually and thus it only takes one to start a new population
  • Found in lakes and rivers
  • Can close operculum to avoid desiccation
  • Out competes native snails and other invertebrate
  • May impact fisheries by reducing food availability

General Characteristics

  • range in size from a grain of sand to 1/8" long
  • color brownish to bluish-green
  • operculum covers opening of shell, which is on left
  • densities reported over 500,000 per square meter!

Links