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Aquatic Invasive Species Distribution

This indicator measures the distribution of aquatic invasive species (AIS) in Lake Tahoe. AIS are non-native organisms that threaten the abundance and diversity of native organisms in Lake Tahoe. Non-native species have been intentionally and unintentionally introduced to the Tahoe Region over the last 150 years. This includes fish such as Lake Trout, mollusks such as Asian Clams, and plants such as Eurasian watermilfoil and curly-leaf pondweed. The presence of these species continues to threaten native taxa of the lake and is a nuisance to users of the lake. The presence of AIS also results in economic impacts for the Tahoe Region with potential costs to tourism, property owners, boaters, and maintenance. Watercraft inspection stations around the Region operate to prevent the introduction of new aquatic invasive species to Lake Tahoe, and there are numerous projects to remove existing AIS infestations. AIS abundance is monitored by TRPA and Environmental Improvement Program partners. 

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Evaluation Map

Distribution of subsurface aquatic plants. Note that this includes both native and non-native subsurface aquatic plants.

2019 Evaluation

Status
Insufficient Data to Determine Status or No Target Established
Trend
Insufficient Data to Determine Trend
Confidence
High
View Evaluation

Applicable Standard

WQ10: Reduce the distribution of known aquatic invasive species.

Key Points

  • 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.

Delivering and Measuring Success

Example EIP Projects

Local and Regional Plans