Currently present in Montana!

New Zealand Mudsnails spread quickly and densely.  Snails may reach densities of 500,000 snails per square meter.  Mudsnail was first spotted in Montana in the Madison River in 1995, but the species has yet to make its way west across the Continental Divide.

Potential harms:

Mudsnail reproduce asexually, meaning it only takes one mudsnail to start a new population.  Mudsnails compete with native snails, often dominating the food chain.  One big concern is their potential to devastate western trout and other recreational fishery populations.

Identification:

• New Zealand Mudnsnails grow to be about 1/8 inch.
• They have an opening to their right when the point of the shell is facing away from you.
• Musnails prefer living in water bodies with stable flows such as springs, spring creeks, and downstream of dams.  They are often found on large cobble or wood pieces. 
  
• They like water temperatures ranging from 32-77 degrees Fahrenheit.

Prevention:

Eradication is almost impossible.  Detecting new infestation early and preventing the spread of them is essential.  Mudsnails are often spread on boating and fishing equipment and gear.  Also, when a mudsnail closes its shell, it can survive several days outside of the water. It is important to follow the Inspect, Clean, and Dry instructions.

Links to more Mudsnail info:

http://www.protectyourwaters.net/hitchhikers/mollusks_new_zealand_mudsnail.php

http://fwp.mt.gov/fishing/guide/ANS/molluscs.html#newzealandmudsnail

http://fieldguide.mt.gov/detail_IMGASY1010.aspx