EL DORADO ? More than 40,000 people were expected to visit El Dorado Lake by the end of Labor Day Weekend, playing on its shores and boating in its waters.

Coast Guard Auxiliary officials are doing what they can this weekend — and the next three — to make sure zebra mussels that have shown up in the lake don’t go home with any of the revelers.

About 150 mussels — the first found in Kansas waters — were found last week between the lake’s dam and the marina cove. It’s unknown how they came to El Dorado, but some think it’s likely they were unknowingly carried in on an infected boat.

“This is a very serious problem,” said Travis Whitt, captain of the auxiliary. “It can virtually kill off the lake.”

Whitt and several volunteer members of the auxiliary planned to spend the rest of Labor Day weekend and each weekend in September showing lake users how to keep the mussels from spreading.

Whitt said he chatted Saturday with people from across the state, Missouri and Texas. Most were aware of the mussel infestation but didn’t know all of the precautions they needed to take to contain them.

Zebra mussels are notorious for attaching themselves to water-intake structures in densities thick enough to shut off water flow, if unchecked. El Dorado gets its water supply from the reservoir.

The mussels also could hurt the ecosystem and threaten other wildlife, including birds, by decreasing food for small fish, which could lead to a decrease in fish populations.

Pam Chaffee, a division staff member who is managing the educational campaign through today, said she hoped the precautionary steps became natural for people.

She asked boaters to drain live wells and leave their boats to dry for five days before going into another lake. Chaffee pointed out that mussels in the larval stage were microscopic.

“Just because you can’t see anything doesn’t mean it’s not there,” she said.

She said it was encouraging that so many people seemed willing to help keep the problem from spreading.

“A lot of people understand what’s at stake,” Chaffee said. “We have no choice now. But we can stay positive and make a difference.”