Invasive Species

Invasive species pose a major threat to ecosystem health in the Tahoe Basin. Past resource management practices, including fire suppression, grazing, development, and logging have significantly altered native habitats. In their altered state, ecosystems are less able to support wildlife and are unable to adequately respond to natural or imposed disturbances.

These degraded ecosystems face a growing threat from invasive species, which can replace native species, alter natural balances and significantly reduce habitat for other plant and animal species. The environmental and economic impacts of these invasions could be substantial as they crowd out native populations, impair habitats and water quality, and reduce recreational opportunities.

The primary focus of this program is to improve the biological integrity of ecosystems in the Basin, and in doing so ensure the existence of a full range of native species, seral stages, habitats, and ecological processes.

Aquatic Invasive Species

Aquatic invasive species such as thick growths of invasive aquatic weeds, clams, snails, and even warm water fish threaten waterways in a number of ways. Consequences of establishment include degradation of water quality, loss of important habitat to native species, impacts to water conveyance structures, and negative economic impacts to the Lake Tahoe Region. Without substantial and coordinated AIS prevention, monitoring, control, education, and research efforts, changes to the Lake Tahoe ecosystem could result in severe impacts to the local economy and unique natural setting.

Watercraft Inspection Program

Aquatic invasive species are known to be transported from infested lakes and rivers via a variety of pathways, for example, recreational watercraft, fishing gear, waders, construction machinery, and rafts. These unwanted species include: the notorious zebra and quagga mussels, Eurasian watermilfoil and curlyleaf pondweed (aquatic weeds), and Asian clams. Despite public awareness campaigns and regulations prohibiting their introduction, both plant and animal invaders are found on boats traveling to or preparing to launch in Lake Tahoe and other waterbodies in the Region. Watercraft inspections are an essential part of preventing this inadvertent transport of alien species into the pristine waters of Lake Tahoe.

For more information on the Watercraft Inspection Program, visit and for information on inspecting non-motorized paddlecraft and becoming a Tahoe Keeper, visit

Lake Tahoe Aquatic Invasive Species Management Plan

There is a plan to protect the waters of the Lake Tahoe Region from the threat of Aquatic Invasive Species (AIS).  The economic impact alone of an introduction is estimated at $22 million per year. As Ben Franklin said, “an ounce of prevention is worth a pound of cure.” Since there are some aquatic species in the Lake already, TRPA is leading a collaborative effort to prevent new AIS as well as control existing invasive species such as Asian clam and certain aquatic weeds.

Lake Tahoe AIS Management Plan

Lake Tahoe AIS Management Plan 20014
Lake Tahoe AIS Management Plan 20014 Appendices

This plan has been approved by the Aquatic Nuisance Species Task Force and endorsed by the Governors of Nevada and California and the TRPA executive director.

The U.S. Army Corps of Engineers, the California Tahoe Conservancy, and the Lake Tahoe AIS Coordination Committee have worked together to compile this plan. All involved agencies appreciate the role the public has played in creating the plan and is thankful for the efforts of everyone to prevent the spread of AIS to the Lake Tahoe Region.  Aquatic invasive species threaten the economic, environmental, and aesthetic value of this important resource to states of California and Nevada.

The goals of the Plan are to:

  • Prevent new introductions of AIS to the Tahoe Region
  • Limit the spread of existing AIS populations in the Tahoe Region, by employing strategies that minimize threats to native species, and extirpate existing AIS populations when possible
  • Abate harmful ecological, economic, social and public health impacts resulting from AIS

Additional studies have been carried out by researchers at the University of Nevada, Reno to measure the survivability and inherent risk of Quagga mussels at Lake Tahoe.

Quagga Survival Risk Assessment 2009