New Zealand mud snails
 immature mud snails |
 operculum exposed |
 live specimen |
 intact mud snail |
Tarita Harju's MS Thesis on NZMS
Vinson and Baker MS on assimilation of NZMS by rainbow trout
Report on the New Zealand mud snails in the Green River, 2005 to 2006
PowerPoint Talk - Utah NZMS Research Update - NZMS Conference Denver, Colorado, 20 April 2005
Report on the Occurrence and distribution of New Zealand mud snails in Utah, 2001 to 2004
Recent newspaper stories
Deseret News, 16 May 2005 - High flows may help ecosystem
Deseret News, 28 April 2005 - Invasion of the mud snail
Deseret News, 23 September 2004 - Testing the waters
Likely habitats
New Zealand mud snails appear to prefer flowing water habitats with stable flows. Springs, spring creeks, and river sections downstream from dams are all places that they thrive in. They are most typically found on larger cobble substrates or on pieces of wood. Routine aquatic invertebrate monitoring using a kick net or Surber net may not detect them as they stick well to rocks and they do not tend to float downstream very far. Pick up and evaluate individual softball sized rocks and larger sticks.
Identifying them
Where dense populations have developed they often look like BBs scattered on the river's bottom. Taxonomically, New Zealand mud snails are in the snail family Hydrobiidae. Hydrobiids can be distinguished from other aquatic snail families by having dextral (opening to the right with the spire pointing away from you) shells with an operculum (a hard calcareous flat that can seal the opening of the shell). New Zealand mud snails are small (~ 1-2 mm) and generally dark colored. A key characteristic for identifying them is that they carry immature snails in their shells. You will need a microscope to see this.If you think you have found some, please store them in small container with preservative (either isopropyl or ethyl alcohol) and mail them to Mark Vinson, BLM Western Bioassessment Center, Department of Aquatic, Watershed, and Earth Resources Utah State University, Logan, Utah 84322-5210
Prevent their spread
To reduce the chance that you may spread them into other areas, either wash your waders when you move between drainages or put them in the sun so they dry throughly. If the snails are kept moist and are not exposed to excessive heat they can live for several weeks out the water by closing their operculum to retain moisture. They are also parthenogenic, which means a single snail can start a new population.For further information contact Mark Vinson at the BLM’s Western Bioassessment Center, 435-797-2038, aqua@cc.usu.edu
Web sites with additional Information:
http://159.189.240.21:8001/FCSC3/Nonindigenous_Species/Untitled/untitled1.htmlhttp://nas.er.usgs.gov/mollusks/
http://www.esg.montana.edu/dlg/aim/mollusca/nzms/
http://espn.go.com/outdoors/conservation/s/c_fea_NZ_snails.html
http://www.flyfishingjacksonhole.com/yellowstone/yellowstone-new_zealand_mud_snail.htm
