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Search Is On for Quagga Mussels in Deer Creek Reservoir

Quagga mussel veliger from Deer Creek Reservoir. This is how a veliger looks under a microscope.
Quagga mussel veliger from Deer Creek Reservoir. This is how a veliger looks under a microscope.
photo courtesy Bureau of Reclamation

Juvenile mussels found last fall

Heber City -- Work is underway to learn if Deer Creek Reservoir has a population of quagga mussels in it.

Last winter, laboratory tests confirmed the presence of five microscopic juvenile quagga musselsócalled veligersóin a water sample collected near the dam in October.

Because adult quagga mussels cannot reproduce in water that's colder than 50 degrees Fahrenheit, there wasn't much risk that quagga mussels would spread in the reservoir over the winter.

"Even though it's still too cold for adult quaggas to reproduce," says Jordan Nielson, aquatic invasive species coordinator for the Division of Wildlife Resources, "the water temperature is climbing. Now's the perfect time to start our spring sampling work."

First step

Collecting water samples is the first step. On April 13, DWR biologists collected the first water samples of the spring.

Collecting water samples is an excellent way to detect mussels, especially juvenile mussels. While adult mussels are easy to see, finding juvenile mussels in a water sample requires microscopes and DNA testing.

"Water samples will be collected from Deer Creek every month," Nielson says, "from now until October or November. Every sample that's collected will be observed under a microscope and tested for the presence of mussels."

Early May

In addition to collecting water samples, starting in early May, the DWR and its partners, including the Bureau of Reclamation and Utah State Parks, will do the following:

Substrate samplers are devices that are attached to lines or ropes that are then attached to buoys. The lines or ropes extend through the water column. Adult mussels that drift through the water column, and come in contact with a sampler, will often attach themselves to it.

"Samplers aren't the most effective way to find adult mussels," Nielson says. "The reservoir is huge, so there's lots of water for adult mussels to drift in. But placing samplers is still worth the effort."

Why the concern?

If a quagga mussel population establishes itself in Deer Creek Reservoir, residents in Salt Lake County and Utah County, as well as anglers and those who enjoy recreating at the reservoir, have plenty of reasons to be concerned. For example, quagga mussels can: