Lake Tahoe has millions of crayfish. Sudeep Chandra has seen for himself. He's a fisheries expert at the University of Nevada, Reno.

"About 240 million little critters living along the bottom, the size of your hand, that's kind of what you can see down there."

But the non-native species stimulates algae growth which clouds up the water.

Right now, it's illegal to sell crayfish taken from Lake Tahoe. But there's an effort to change that for two reasons: one is to help the local economy by selling the crayfish to restaurants. The other is to improve the lake's clarity.

"It's probably a good idea to start thinking about removing them from the lake. But the question will be - can you actually remove enough of them to have an impact. And the science hasn't come up with an idea for that yet."

The proposal to put crayfish traps on the lake bottom still needs the approval of state and regional agencies.

Critics say trap buoys on the lake surface could interfere with boating traffic.