Jim Grant / Tahoe Daily Tribune
Inspectors decontaminated six vessels for invasive mussels over Memorial Day weekend and found three more cases that raised alarm, a Tahoe Resource Conservation District spokeswoman said Tuesday.
Nicole Cartwright, a conservation planner for TRCD's invasive species program, said quagga mussel shells were found May 18 at the Tahoe Keys on a 30- to 35-foot Sea Ray boat, purchased from Lake Pleasant, Ariz. That boat was decontaminated Tuesday at the TRCD office near Emerald Bay.
"This shows us that the inspection program is working and the inspectors are taking their job seriously," said Dennis Oliver, a spokesman with the Tahoe Regional Planning Agency.
Five other boats underwent a full- to-partial decontamination during the holiday weekend, but did not have shells on their engines, hulls or other parts, Cartwright said.
"There were not physical mussels but they were from at-risk areas and had some kind of standing water," Cartwright said.
On Sunday, inspectors also found a 40-foot Chris Craft and 32-foot Grand Banks at Obexer's Boat Company at Homewood with mussel shells. The shells were not quagga or zebra mussels, and California Department of Fish and Game biologists are investigating if they are a salt-water subspecies, said Warden Bob Pera.
"No matter what they are, these boats are going to have to be decontaminated," Pera said. "We know at least they don't belong in Lake Tahoe so they are not going to get there."
The vessels, which hailed from the Alameda and Oakland areas in California, are scheduled for decontamination Thursday and a final inspection Friday, Pera said.
Another vessel was inspected at Ski Beach in Incline Village, and found to have barnacles attached to it, but was not decontaminated, Cartwright said.
In January 2008, zebra mussels were found at San Justo Reservoir, about 250 miles away from Lake Tahoe. Shortly after, the bi-state federal Tahoe Regional Planning Agency enacted new polices requiring boat inspections.
Beginning in June boaters will have to pay for inspections on a sliding scale to fund the program.
Quagga and zebra mussels multiply rapidly once introduced to a water source. They can clog infrastructure, destroy boat engines and leave layers of sharp shells on beaches. They have never been successfully removed from a large body of water.
They are not known to be present in Lake Tahoe.
These are the latest cases when inspectors have found invasive mussel on a vessel attempting to enter Lake Tahoe. In August 2008 inspectors quarantined a 32-foot cabin cruiser after discovering a quagga mussel shell on its engine.