The mussels can also severely impact fisheries, aquatic life and tourism as a result of sharp shells lining the beaches of popular recreation areas.
"I can picture what Lake Powell is going to look like and it isn't pleasant," said Greg Sheehan, director of the Utah Division of Wildlife Resources (DWR). "Every beautiful sandstone outcropping will be encrusted with snails. The days of running barefoot on the beaches will be gone."
The growing number of mussels at Lake Powell the recreation area's website says more than 1,300 adult mussels have been removed does not mean attempts to prevent other waters will be halted.
"We are going to tighten up our efforts to educate boaters and make sure they know the threat they could carry with them if they leave Lake Powell with water in their boat," said Jordan Nielson, aquatic invasive species coordinator for the Utah DWR. "We need to make every effort to keep mussels from getting to other waters."
The Utah Legislature agrees that preventing quaggas from spreading is a high priority. The Legislature appropriates $1.35 million each year to provide high-pressure hot water cleaning stations and the staff to operate them at numerous boating destinations.
A new bill, SB212 "Invasive Species Amendments," is being considered during the current legislative session. The bill would allow Utah wildlife officials to create inspection stations at state borders. People hauling boats could face a Class B misdemeanor for failing to stop at the checkpoints.
If SB212 passes the annual appropriation for the aquatic invasive species program will likely increase.
Utah waters have dodged several possible quagga infestations as young mussels were detected at two reservoirs Red Fleet and Electric Lake. But reproduction never occurred and the waters were eventually deemed quagga free. A single adult quagga was found at Sand Hollow Reservoir, but no other quagga mussels were ever found on the water near Hurricane.
The first sign of a quagga mussel at Lake Powell showed up in a water sample in the summer of 2007. The reservoir then proved negative for the presence of quagga for several years before the current population emerged.
Nielson said there are developments with a bacterium that will kill quagga mussels and also invasive zebra mussels but that the cost of treating a reservoir as large as Powell (with a water capacity of 27 million acre-feet) would be prohibitive. The effectiveness of such a treatment would also be questionable. The bacterium would likely prove useful, if approved, on smaller lakes and reservoirs, Nielson said.
Boaters at Glen Canyon National Recreation Area will still have to have their vessels inspected and decontaminated if there's a risk of carrying mussels or other invasive species from known infected waters.
To help prevent the mussels from moving to other unaffected lakes and reservoirs, watercraft owners who visit Lake Powell will need to decontaminate their vessels before launching at another location.