Lake invaders

Invasive species prevention and control at Lake Tahoe

Julie Regan at the Tahoe Regional Planning Agency office.

Julie Regan at the Tahoe Regional Planning Agency office.

Photo/Sage Leehey

For more information about boat inspections at the lake, visit

Invasive species have been intercepted on about 30 boats this season by Lake Tahoe inspectors.

Quagga and zebra mussels are two invasive species that officials are trying to prevent from entering the lake, according to Julie Regan, Tahoe Regional Planning Agency’s chief of external affairs. Quagga mussels, specifically, could pose a huge threat to the ecosystem of Lake Tahoe because they change the chemistry of the water.

“While they’re filter feeders, and there could be short term boosts in clarity, the long-term consequence is a huge negative impact on the fishery, on the food web of the lake as a whole and of scenic and resource degradation where they attach to piers, they attach to any structure, rocks,” Regan said.

There are four inspection stations where boaters can have their vessels checked before entering the lake. After a clean inspection, the boater receives a wire seal that must be broken in order to launch the boat and marinas check for this. They receive a new seal when leaving the lake.

Lake Tahoe already has a few species established in its depths, including Asian clams, Eurasian watermilfoil and curly-leaf pondweed.

Programs to manage and attempt to rid the lake of these species have been largely successful, and TRPA is researching more ways to handle them. The biggest issue is funding, though, because the federal funding is drying up, and boater’s fees cover about half of the overall cost of the inspection and control programs.

Regan said the presence of quagga mussels in the lake could harm or destroy various aspects of the region’s economy as well.

“We have a wedding industry in Lake Tahoe, so imagine people trying to have their wedding on a beach that is littered with degrading quagga mussel shells,” Regan said. “They could really ruin the recreation value of what we consider a pristine environment here in Tahoe.”

The tendency of quagga mussels to attach to just about anything poses a threat to water infrastructure, too, because they can clog water intake lines, forcing water purveyors to pay to chisel them off.

Other areas have already seen the effects of invasive mussels, including Lake Mead, Lake Havasu, Lake Pleasant, the Great Lakes and the Mississippi River system. According to TRPA aquatics resources program manager Dennis Zabaglo, boats coming from Lake Mead in Southern Nevada to Tahoe are the most common boats to be carrying mussels. Regan said Lake Mead has trillions of mussels and the problem is more difficult to handle there and in other places than in Tahoe.

“We’re fortunate where we have a watershed where we can see all the access points going into the lake and we can manage that with our problem versus other places, like Lake Mead, where there are multiple entry points, where it’s almost impossible to have an inspector present at every possible inspection site,” Regan said.

The best way to prevent carrying invasive species into the lake is to clean, drain and dry your vessel immediately after leaving a body of water. This will also speed up the inspection process when re-entering Lake Tahoe.