PAGE — More than 150 invasive mussels have been found at two marinas at Lake Powell over the last month.
Officials with the National Park Service say the individual adult quagga mussels found at the Wahweap and Antelope Point marinas weren't close enough to successfully reproduce.
The mussels are being physically removed from the lake, which straddles the Arizona-Utah border.
The mussels have multiplied quickly in other waterways across the West, clogging pipes and intakes, and depleting food sources used by aquatic creatures.
Glen Canyon Ecologist Mark Anderson says it's likely the mussels were introduced via ballast or bilge water from boats that were not cleaned, drained or dried.
Officials say boats, docks and cables in the Wahweap Bay and Antelope Point areas will continue to be assessed by the park service and other dive teams.
NPS Superintendent Todd Brindle remains hopeful the latest results are not evidence of an established population of mussels.
"With this early detection, the mussels are being physically removed from the lake, decreasing the potential for them to reproduce," Brindle said.
"Prevention is still the most effective way to fight invasive species, so we will continue the boat inspections that are currently in place," he said. "Everyone needs to continue to clean, drain, and dry their boat and equipment after every use."
Next door in Nevada, scientists have documented a nearly tenfold increase in quagga mussels in Lake Mead since they first were confirmed there in 2007.
Researchers at the University of Nevada-Las Vegas estimated last year that Lake Mead hosts more than 1.5 trillion adult quagga mussels, which are about the size of a dime, and 320 trillion microscopic baby quagga mussels.
Nobody knows exactly how the mussels got there. Some speculate they hitchhiked aboard a boat from the Great Lakes region, where the mussels have been proliferating for more than 20 years after arriving in the ballast of ocean-going ships from Eastern Europe.
The outbreak has raised concerns in a number of neighboring states.
Officials for the Northwest Power and Conservation Council say nearly 80 infested boats were stopped last year on the borders of Idaho, Montana, Oregon and Washington, most coming from Lake Mead.