The largest Asian clam control project at Lake Tahoe begins Oct. 15 at the mouth of Emerald Bay with the treatment of up to 5 acres.

The goal is to treat a small, isolated population of Asian clams before they spread to an unmanageable level. Clams live on a shallow, gravel sill that partially separates Emerald Bay from Lake Tahoe. Treatment will be accomplished by covering the infested lake bottom with thin rubber barriers, augmented with organic material, that reduce the available oxygen and smother the clams.

Asian clams have a variety of negative impacts. They could increase the potential for other species such as quagga mussels to establish in Lake Tahoe by increasing localized calcium concentrations. They also promote the growth of algae by releasing highly concentrated nutrients. Increases in algae impact the scenic beauty of the shoreline by changing the water color, reducing water quality, and washing rotting materials onto the beaches.

Asian clams also compete with native animals for habitat and food, which causes a disruption in the food web.

Bottom barriers are hand placed by divers over known populations of Asian clams on the bottom of the lake. Steel rebar on top of the barriers keep them in place and deny the clams oxygen. By adding thin, woven sheets of biodegradable organic material under the rubber mats the loss of oxygen can be accelerated to improve the effectiveness of the treatment method. Organic material that does not decompose during the project will be removed with the bottom barriers.

The Tahoe Regional Planning Agency is the lead agency in the project.