Quagga Mussels Reach Record Numbers in Lake Mead, UNLV Research Finds

Boaters encouraged to follow a three-step process to properly decontaminate boats.

More than 1.5 trillion adult quagga mussels and 320 trillion baby quagga mussels live in Lake Mead, according to new calculations from researchers at UNLV. That's nearly 10 times the amount of mussels in the lake since they were first discovered in 2007.

As Memorial Day weekend approaches and the boating season begins, nearly 5,000 boaters from around the Southwest could visit Lake Mead. UNLV researchers are urging that boaters follow proper decontamination procedures to prevent the mussels from infecting lakes and water supplies around the region.

"Many visitors will be from California and other surrounding states and if we don't do a good job of decontaminating boats, the mussels are going to end up everywhere and very quickly," said UNLV researcher David Wong, one of the nation's leading experts on invasive freshwater species. "We have found that some mussel babies could survive on a boat out of water for as long as 27 days. They can survive many conditions. Many people just don't realize how resilient these mussels are."

Quagga mussels, about the size of a dime when fully grown, are an invasive species that cling to water pipelines, attach to boats and lake structures and cripple the lake's ecosystem, costing lake managers millions of dollars in cleanup each year. Many have already spread to water systems throughout neighboring states.

The estimated 320 trillion "invisible" mussel babies are the real culprits. They swim in the water and can only be detected under a microscope, making it impossible to ever fully eradicate mussels from the Lake. Their small size can also lead boaters and other visitors to inadvertently transfer the mussels to another water source, Wong said.

Researchers don't know exactly how the mussels arrived at Lake Mead, though the most likely source was a boater from the Great Lakes region where quagga mussels have been wreaking havoc for more than 20 years.

Warmer water temperatures of Lake Mead create the perfect breeding ground for the, allowing for year-round reproduction and higher levels of calcium in the water speed shell growth.

To properly decontaminate a boat, Wong suggests a three-step process: Clean, drain and dry.


If a boat has been in the lake for a day or over the weekend, the boat can be hosed off with tap water. Boat owners should try to remove any areas that could potentially be infested.

If a boat has been housed at the marina and has been in the lake for more than two weeks, owners must decontaminate the boat or hire someone to do this.

Wong recommends that the boat be cleaned with pressurized water heated to 140 degrees or higher, which should be pointed toward each area that could have been exposed for at least five seconds. Depending on the size of the boat, this process could take 30 minutes to three hours.

It is not recommended to use chemicals or bleach to clean boats because the chemicals could be brought into another water system and cause harm, Wong said.


Drain any places in the boat where water could have collected. There are many places that hold standing water that boat owners tend to overlook such as the circulation systems for water, barge water or ballast water.


Wong recommends that a boat dry for two to three days before it is used in any other body of water. If there is any residual water left, this could lead to a much longer drying time. UNLV graduate students studying under Wong recently found that some baby mussels can live for as long as 27 days in wet or humid conditions.

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