New Zealand Mud Snail – Oneida County Aquatic Invasive Species Program

Identification: New Zealand mud snails have a dextral coiling with 7-8 whorls. The aperture is oval and its height is less than the height of the spire. Shell colors can vary from light brown to dark brown. It is usually 4-6 mm long.

Ecology and Natural History: New Zealand mud snails are native to New Zealand in lakes and streams. They are naturalized in Australia and Europe. They are believed to have been introduced to the United States through ships from Europe of from shipping gamefish with infested water to the western United States. New Zealand mud snails feed on plant and animal detritus, algae, sediments, and diatoms. A snail produces about 230 young per year. It can survive passage through guts of fish and can be transported to different waterbodies this way.

Impacts of Introduction: New Zealand mud snails can tolerate a wide range of habitat, allowing them to inhabit all shallow water. Their large population size and feeding habits can out-compete out native snails and clams for valuable resources. It is suspected that they can alter primary production in streams.