Invasive New Zealand Mudsnails Found in Lake Tahoe

Lake Tahoe — Divers surveying Lake Tahoe have discovered the invasive New Zealand mudsnail in areas off the South Shore, according to the Tahoe Regional Planning Agency (TRPA) and the Tahoe Resource Conservation District (Tahoe RCD).

This is the first time the species has been detected in the Tahoe Basin. The New Zealand mudsnail is a small freshwater snail native to the island country in Oceania. It is a small invasive aquatic species (IAS) that has become a concern in various parts of the world, including North America, Europe and other regions where it has been introduced. Aquatic invasive species are non-native plants, animals and pathogens that can harm native ecosystems, economies and recreational activities.

The Lake Tahoe Aquatic Invasive Species Program includes comprehensive monitoring of Lake Tahoe for aquatic invaders. Contract divers with Marine Taxonomic Services, Ltd. surveying invasive weeds on the South Shore discovered tiny snails on the bottom of the lake about a half mile offshore from the mouth of the Upper Truckee River.

Experts and a DNA lab analysis confirmed the species is New Zealand mudsnail, which also has been detected in nearby waterways, including the Lower Truckee River downstream from Lake Tahoe near Reno, Nev. No other IAS, such as the destructive quagga and zebra mussel, have been detected, according to the agencies.

Following rapid response protocols under the federally approved Lake Tahoe Aquatic Invasive Species Management Plan, TRPA assembled an incident team of agency staff, Tahoe RCD and partner experts. The team is quickly deploying scientists, beginning with lake-wide dive surveys to determine the extent of the infestation, with plans to share all available information with state and federal wildlife managers through the Lake Tahoe Aquatic Invasive Species Coordinating Committee. For continued updates and information, visit the New Zealand mudsnail page.

“Lake Tahoe is one of the most protected waterbodies in the United States, and our aquatic invasive species monitoring program is credited as the reason for this concerning discovery,” TRPA Executive Director Julie Regan said in a press release. “It is critical that everyone remain vigilant and adhere to the mantra of Clean, Drain and Dry. Every boater, paddler and angler shares the responsibility to protect Lake Tahoe’s native species and the waters we enjoy.”

According to TRPA, as climate change takes its toll on Lake Tahoe’s native ecosystem, the threat of new invasive species in the region will also increase. Under the Lake Tahoe Environmental Improvement Program, officials are helping protect water quality and native species in the case of further discoveries. It is a crucial program to improve the region’s climate resilience, according to TRPA.

Invasive species can be transferred to new environments through various pathways, often facilitated by human activities. The movement of invasive species can be intentional or unintentional. They can hitch a ride on boats, fishing gear, paddle craft, life vests, and beach toys, according to the National Stop Aquatic Hitchhikers! Campaign. The most effective way to prevent their spread is to Clean, Drain, and Dry boats and gear before entering a new waterbody.

Since 2008, the Lake Tahoe Aquatic Invasive Species Program has coordinated efforts to prevent the introduction and spread of invasive species in Lake Tahoe.

“Lake Tahoe’s robust watercraft inspection program, and commitment from the public, shows that preventing the spread of aquatic invasive species is possible,” said Lisa Heki, Lahontan National Fish Hatchery Complex Project Leader, U.S. Fish and Wildlife Service in the press release. “Now more than ever, we have to support and strengthen our work with anglers, boaters, paddlers, and everyone who interacts with the waters of Lake Tahoe and its 63 tributaries.”

Periodic monitoring for invasive species in the basin is necessary for the Lake Tahoe AIS Management Plan. Early detection and rapid response are essential in helping agencies control the spread of invasive aquatic weeds introduced before the inspection program, such as the ongoing weed removal project in Emerald Bay

TRPA advocated for federal funds to be set aside for early detection and rapid response actions throughout the nation. Tahoe agencies use critical federal funds to address the New Zealand mudsnail introduction.

For updated information on the response and potential protocols for the management of the infestation, visit the TRPA New Zealand mudsnail page.