New Zealand Mudsnails – Why They are a Concern

The New Zealand mudsnail is an invasive snail that is ovoviviparous (live bearing) and parthenogenetic (reproduces asexually). Therefore, it only takes one snail to start a new population. The snails are very small and can easily be tracked to other areas and waters. 

Where New Zealand Mudsnails are Found

These snails were first found in Arizona in 2002 in the Colorado River below Lake Powell in Lees Ferry, and then progressively moved downstream through the Grand Canyon and into Lake Mead and Lake Mohave. In 2019, they were detected in AZGFD’s Page Springs Hatchery. They have also been detected in Tonto Creek, Canyon Creek, Oak Creek, the lower Verde River below Bartlett Dam, and the lower Salt River.

New Zealand mudsnails are a concern because they compete with native invertebrates for food, posing potential harm to Arizona’s native and sportfish populations, as well as native mollusks. AZGFD reminds anglers and recreationists to “clean, drain and dry” – and especially decontaminate — their equipment or watercraft before exiting waters designated as having AIS.

Decontamination options

Mudsnails in Canyon Creek
Number of mudsnails in a 1-ft. square sample
Mudsnails abundant in Canyon Creek

How to stop the spread

Decontamination options for anglers and recreationalists, required when angling or recreating at affected waters.

Angling technique recommendations

Consider these options to help minimize the spread of these aquatic invasive species

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