Pond Boss Forums GENERAL QUESTIONS Pond Boss Using a pond liner to suffocate Asian clams.

I thought some of you might find this interesting...

Scientists suffocate Asian
clam beds with rubber tarps

Lake Tahoe, Nev. —
Come all ye pioneers of clam killing. In collaboration with a variety of environmental oversight agencies, Lake Tahoe scientists unveiled the first stage of an experiment designed to test the effectiveness of a nascent technique aimed at curtailing the population growth of non-native freshwater mollusks. A team of scientists, spearheaded by Geoffrey Schladow, director of the Tahoe Environmental Research Center, rolled out a series of 100-foot by 10-foot black bottom barriers and spread them over a half-acre portion of the bottom of Lake Tahoe in the general vicinity of the Round Hill Pines Beach and Marina, where Asian clam populations have become increasingly prevalent in recent years.

The bottom barriers are a 45 mil thick pond liner capable of depriving organisms of dissolved oxygen necessary for survival. “The goal of this experiment is to determine whether it is feasible to control clams using impermeable bottom barriers,” Schladow said. “We need to know how to efficiently deploy and remove large areas of rubber sheeting, and when it is all done, we must know whether the clams recolonize the treated areas.” Schladow said the experiment will also be important in assessing if the cost of implementing control measures is practical.

The experiment could have far-reaching implications if deemed successful by scientists come September, when the barriers are scheduled to be removed. “Bottom barriers have been used in Tahoe to kill underwater plant species, but the scale of this project and the fact it relates to Asian clams makes it unique,” Schladow said.

The project

The University of California at Davis deployed two research boats and a modestly sized barge. One research boat was used by three divers tasked with the installation of the bottom barriers while two scientists remained on the boat to oversee the mission. The barge was equipped with a small portable crane operated by Bill Sluis, research engineer at UC Davis, and his team. Sluis began the mission by using the crane to pick up large rolls of black rubber and drop them into the water. The rolls were then suspended underwater by flotation devices, while the three divers unrolled the tarpaulin material. The divers then secured the barriers at the bottom before surfacing with examples of Asian clams both living and dead. When alive the clams have a golden sheen, when dead they turn white and are visible from 30 feet or more from the bottom of the Lake. Scientists will duplicate the experiment off the shore at Lakeside, meaning a full acre of the bottom of Lake Tahoe will be covered until September.

I am betting it would work for the short term, but all it takes is one Asiatic clam to survive. Within minutes it's squirting out 1000's of babies to recolonize the area that just had all of the clams killed off. I just can't see a way for them to kill off all the clams in the lake using this method. However, if they are just trying to keep the clams at controllable levels, this may work but I am betting it would be fairly expensive. Interesting idea though...

Sounds like a fun experiment but as you say CJ it's about as practical as horsehoes on a duck. Jeeze Lake Tahoe has a surface area of 192 square miles!

And deep and clear, the maximum depth of Lake Tahoe is 1,645 feet, the average depth is 1,000 feet and the average Secchi depth reading is 67.7 feet. That my friends is one hell of a pond.

Doesn't appear there would be much for the clams to eat with that kind of clarity and probably cold temps. I can't imagine they'd be a problem.

Doesn't sound like prime Asiatic clam habitat but they seem to be thriving...

UC Davis prepares an annual "Lake Tahoe Health Report." In the report released in August 2009, UC Davis found up to 3,000 Asian clams per square meter in one section of the lake.

It's a clamity I tell you!

Trying to kill a clam, but what about all the aquatic spottedgerbilfrogs that will be killed?

Wow must be a coldwater clam. I just can't imagine what they could be eating with that kind of clearity!

Folks you better get your pond liners now! Due to demand the cost will skyrocket!

No worries, after the clams are killed, California will spend three hundred million dollars and pass 19 new laws protecting the aquatic spottedgerbilfrogs and restoring it's habitat.

Hey Jeff what do you think of that city manager in Kalifornia that was getting $800,000 a year and the police chief that was getting $400,000 a year?

Talk about fleecing the taxpayer!

If you knew the city, you'd be even more outraged. I won't say more or I might get spanked.

So they paid more and got less!

Truly shameful.

This is a "municipality" in Los Angeles county that only has 38,000 people in it. It is a poor (average household income of $39,394), gang ridden area (seven active gangs claim Bell as their home) that only occupies about 2.5 square miles. It is an area much like Compton that, if you are wise, you avoid like the plague.