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Precaution Taken After Invasive Mudsnails Detected In Creek 2.5 Miles Downstream Of Hatchery

The Arizona Game and Fish Department (AZGFD) has confirmed the presence of New Zealand mudsnails, an aquatic invasive species, in Tonto Creek approximately 2.5 miles downstream of Tonto Creek Hatchery. AZGFD continues to conduct surveys in the area to determine the extent of infestation.

Beginning June 22, the Tonto Creek Hatchery was closed to the public. This will provide the department with time to enhance biosecurity protocols and evaluate infrastructure investments that could further bolster biosecurity.

The New Zealand mudsnail is an invasive snail that is ovoviviparous (live bearing) and parthenogenic (reproduces asexually). To that point, it only takes one snail to start a new population.

These snails were first found in Arizona in 2002 in the Colorado River below Lake Powell in Lees Ferry, 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 also have been detected in Oak Creek, the lower Verde River below Bartlett Dam, and the lower Salt River at Granite Reef. In April 2023, the snails were detected in Canyon Creek, and the Canyon Creek Hatchery was subsequently closed to the public to also evaluate and enhance biosecurity at the facility.

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.