• The first basin-wide survey of the extent of native and invasive aquatic plants was completed in 2020. Excluding the Tahoe Keys lagoons, the survey documented lakewide nearly 30 acres of Eurasian watermilfoil infestation and 8.8 acres of curly-leaf pondweed infestation.
• Invasive plants infest nearly 90 percent of the 170 acres of the Tahoe Keys lagoon channels.
• Other infestations were documented around the Lake, including established invasive plant populations in the southern portions of the lake, including at Timber Cove Marina, Tallac Marsh, and Edgewood Golf Course.
• Asian clams were first found in the southern portions of the lake, and have previously spread to the north and east shores with large infestations found and treated at Sand Harbor, Marla Bay, and Emerald Bay.
• Treatment for the Asian clam infestation in Sand Harbor started in 2017 and was completed in June 2020.
• Treatment plans are being developed for nearly every identified AIS infestation in Lake Tahoe.

Relevance

Maintaining the biological integrity of Lake Tahoe’s nearshore environment is a longtime goal of resource managers in the region and has been set forth in a variety of planning documents. Submerged aquatic vegetation is an important biological component within Lake Tahoe’s nearshore context. Knowing the status of submerged aquatic plant populations at Lake Tahoe has become increasingly important to nearshore managers due to the introduction and spread of invasive species such as Eurasian watermilfoil (Myriophyllum spicatum) and curly-leaf pondweed (Potamogeton crispus). Aquatic invasive plants when left unchecked can affect fishing experiences, water quality, fish and wildlife habitat conditions, human and animal health, vessel navigation, and the recreation values of water bodies.

Human and Environmental Drivers

Non-native species have been both intentionally and unintentionally introduced to Lake Tahoe over the last 150 years. Habitat modification such as channelization and modification of the Truckee Marsh for the Tahoe Keys also created micro-environments within the lake that may be more suitable for colonization by AIS. Climate change further threatens to alter the lake’s physical environment, with the potential for making further AIS establishment more likely.

Example EIP Projects

• Aquatic Invasive Species Veliger Monitoring

  This EIP project monitors for the presence of Quagga and Zebra mussel and Asian clam veligers in Lake Tahoe.

• Sand Harbor Aquatic Invasive Asian Clam Control

  This project treated 16 acres of an estimated 22 acre Asian clam infestation at Sand Harbor.

Local and Regional Plans

• Aquatic Invasive Species Action Agenda 2021-2030

  The AIS Action Agenda identifies priority projects and establishes treatment goals for the next 10 years.

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