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Science | Environment

Why Aren't Quagga Mussels Flourishing In Northwest Waters?

Zebra and Quagga mussels are one of the most damaging invasive water species in the United States, but for some reason, they haven't yet infested the Pacific Northwest.

Researchers at Portland State University are trying to find out why. Ryan Knutson reports.

Brian Adair is a graduate student at Portland State University. Last week, researchers captured the sounds of him filling 25 five-gallon jugs with water from the Columbia River. Then he drove it to Lake Mead in Nevada.

 Silent Invasion
Something troubling is taking hold in Oregon. Strange, exotic plants and animals are showing up in places where they don't belong. They are invasive species, and they're taking over landscapes, driving native wildlife away, and making everyone from ranchers to fishermen to wildlife managers nervous. What are these invaders? Where do they come from? And what can we do to stop them?
Learn More…

He’s trying to help solve something of a mystery about Quagga and Zebra mussels ­ Why they aren’t in the Columbia River Basin.

Brian Adair: “We are going to grow Quagga mussels in the Columbia River water and see how well they will survive.”

Scientists suspect it might have something to do with the water.

Brian Adair: “The Columbia River has much lower levels of dissolved calcium than Lake Mead, and in fact it’s low enough that some people predict that Quagga mussels won¹t do well.”

But why does calcium matter? Adair helped explain this over the phone from a former fish hatchery at Lake Mead where he’s conducting the experiment.

Brian Adair: “Calcium is very important in producing their shell, which is their first line of defense against everything.”

There’s plenty of calcium in Lake Mead. The hatchery was recently shut down after being overrun by mussels. Adair plans to drop Lake Mead’s mussels into Columbia River water and see what happens.

Brian Adair: “Things that may be causing mussels to perform poorly in low calcium waters is that muscle that holds their shell shut may not function as well. And if they can't hold their shell closed, they can become vulnerable to all sorts of parasites that can get in.”

The inability to close their shells also makes them weaker in cold water.

Brian Adair: “If the water gets too cold, a lot of times their response is to close up and go dormant, and if they’re not able to close up that water could get under the shell and possibly cause damage.”

It’s a good thing that these mussels aren’t infesting the Northwest, though. A study from the Pacific States Marine Fisheries Commission suggests it would cost more than $20 million  just to purchase the first stages of defense against the mussels, not including the ecological cost to salmon stock.

Michael Milstein: “It’s hard to even chip them off with a chisel or something, because they latch on so tightly.”

That’s Michael Milstein of the Bonneville Power Administration. He says these mussels are a big concern for the BPA, which operates more than a dozen dams throughout the Columbia River Basin.

Michael Milstein: “They grow incredibly fast, multiplying by the millions, to the point where they clog pipes and the obstruct the flow of water through parts of the dam.”

The BPA is spending $183,000 to fund the research Adair is working on with the Columbia River water, with the hope researchers will be able to unlock one of the secrets for keeping these mussels out of Oregon’s waterways. Adair will be working in Nevada through next month.

Quagga Mussels — Oregon Field Guide

In January 2007, tiny quagga mussels from Europe invaded Lake Mead, Nevada. Within months, they began fouling boat engines, docks, and the water intakes of Hoover Dam. Now quaggas are spreading across the west and Oregon is bracing for a costly invasion that threatens everything from hydropower to salmon recovery. Learn more about the threat posed by this invasive species and the prevention efforts underway to stop their spread to Oregon.