The New Zealand mud snail is a very tiny aquatic snail (often smaller than your baby fingernail) and is native to fresh waterbodies in New Zealand. The New Zealand mudsnail is typically light to dark brown in colour but may look black when wet. The shell of adult mud snails usually have 5 – 6 whorls that lean to the right, are less than 5 mm in size and can easily be confused with other fresh water and native snails.
It is thought that the New Zealand mudsnail was transported to North America in the ballast water of transport ships originating from Europe and Asia. It was first recorded in North America in the late 1980’s in Idaho’s Snake River and is now widespread in many states including Washington, Oregon, and California.
The New Zealand mudsnail can live in a variety of habitats including lakes, rivers, streams, lagoons, estuaries, canals, ditches and water tanks. It can tolerate a variety of water temperatures and conditions but seems to thrive in disturbed watersheds. They are often found living in high densities (greater than 400,000 snails/sq meter) and can disrupt the natural ecology by out-competing native aquatic snails and insects..
In North America, it is believed that the main method of spread of the New Zealand mudsnail has been through transportation of the snail on fishing, boating and recreational gear. Because of its size and ability to attach to objects, it’s an ideal aquatic “hitch-hiker” that can be unknowingly transported to a new waterbody with ease.
What can you do? Make sure to clean, drain, and dry your boat and fishing equipment after each use and before entering a new waterbody. Make sure all plants, animals and mud are removed from your boat and fishing equipment, and any item that can hold water such as the bilge, bait buckets, or ballast water has been drained on site. This is especially important as the New Zealand mudsnail can survive out of water for weeks if left in damp, cool conditions.
Because the New Zealand mudsnail is parthenogenetic (a form of asexual reproduction in which growth and development of the embryos occurs without fertilization) it only takes one mudsnail to create an serious negative impact.
Report any New Zealand mudsnail sightings to your local Invasive Species Organization, or the Invasive Species Council of BC at 1- 888-933-3722.