Divers’ Attack on Invasive Clams May Slow Lake Tahoe Boatsposted: 10/19/2012
Boaters may experience some delays entering Emerald Bay during the next six weeks while divers deploy an underwater attack on invasive species that are cited as harming Lake Tahoe’s famous clarity by promoting algae growth.
The Lake Tahoe Aquatic Invasive Species Program will begin treating about 5 acres of infested area this month, in the largest project of its type in lake history.
The clams live on a shallow gravel sandbar about 15 feet below the surface, at the mouth of Emerald Bay on the southwest shore of the lake.
It will take the divers four to six weeks to lay down thin rubber barriers, augmented with organic material, that reduce the available oxygen and smother the clams. The barriers will be left in place for about one year.
“This is a physically demanding undertaking,” said Dr. Geoffrey Schladow, director of the University of California, Davis Tahoe Environmental Research Center. “The project team is laying down over 4 miles of barriers, in very cold water at the mouth of Emerald Bay, where water currents are known to fluctuate rapidly.”
Without treatment, the clam population could grow rapidly and become extremely difficult and expensive to control, scientists said. By treating the Emerald Bay infestation in the early stage, these impacts can be minimized or avoided, according to Schladow.
Boaters are asked to remain at least 200 feet away from the project area, which will be designated with floating flags and may be closed off for short periods of time. Work will primarily occur during early mornings and on weekdays. No work will occur on weekends or holidays, in order to reduce boater inconvenience.
Dan Shaw, environmental scientist for the California Department of Parks and Recreation, said the effort will be worth the inconvenience, in the long run.
“Preserving the exceptional boating and recreation opportunities in Emerald Bay State Park is important to us,” Shaw said. “We are asking the boating community to exercise caution and a little patience when enjoying Emerald Bay, for the next month.”