No new signs of mussels

Testing of water samples taken throughout Montana has been completed with no new detections of invasive mussel larvae, according to the incident-command team assembled last month to address the issue.

Jeni Flatow, a spokeswoman for the Montana Mussel Response Team, said the results of all water samples taken by the state were received in recent days, with the confirmed cases of mussel larvae limited to several positive test results in Tiber Reservoir.

After initial tests revealed suspected mussel larvae in Canyon Ferry Reservoir and the Missouri and Milk rivers, further sampling resulted in no new positive hits.

Of 610 water samples the state processed this year, all 21 samples from Flathead Lake contained no mussel larvae. While none have been detected west of the Continental Divide, many scientists and state officials worried the contamination could have also spread to the Columbia River Basin.

“All of the Flathead samples that were processed by the state lab were done, and we didn’t have any additional samples that were suspect,” Flatow said.

The first case of invasive mussel larvae in the state was confirmed Nov. 8, sending state officials scrambling to determine how far the destructive species had spread throughout Montana’s water bodies. Later that month, Gov. Steve Bullock declared a natural resource emergency and assembled the incident-command team to focus the state’s response to the issue.

While the news is encouraging, Flatow stopped short of giving a clean bill of health to water bodies that had not yielded any positive test results. Shortly after news of the mussel larvae detection broke, teams of dogs specially trained to sniff out zebra and quagga mussels — the two invasive mussel species responsible for major ecological and economical impacts in many other states in the West — appeared to detect the bivalves in Canyon Ferry as well.

One of the two teams of “mussel dogs” used in the response was provided by the Flathead Basin Commission, which helps manage mussel-prevention efforts in the watershed.

The commission’s executive director, Caryn Miske, said the response team’s report is good news, but the detections in Tiber show there’s a need to beef up the state’s prevention strategy.

“We were all in agreement that monitoring at a much higher level, with much more frequency, would be needed for five years until we know we are free and clear” in the Flathead, Miske said. “Detecting mussels is not necessarily an easy business, and what happens often is you don’t detect the mussels until they are pretty well advanced.”

On Dec. 1, Montana enacted boating restrictions on Tiber and Canyon Ferry until the seasonal ice-over of the two reservoirs.

“That’s perhaps the easiest option — perhaps not politically — as a management tool,” Miske said. If those restrictions are lifted, she hopes the state will put a strict “exit strategy” in place for boaters leaving those waters.

The commission is seeking more funds to increase the number of check stations around the Flathead drainage, Miske said, and to operate them for longer hours during the boating season. She also believes Montana needs to step up enforcement by mandating inspections for all boats launching in Montana’s waters, similar to Wyoming’s boat-inspection law.

Meanwhile, researchers with the University of Montana’s Flathead Lake Biological Station in Yellow Bay are conducting their own DNA testing of water samples taken in Flathead Lake to confirm that none of the mussels have been spread west of the Continental Divide.

Earlier this month, Bio Station professor Gordon Luikart said those results could begin trickling in before the first of the year.

As the state’s response team continues honing its containment strategy, Flatow said sampling will continue on those water bodies that initially yielded “suspect” results.

“I think the focus is going to be on control and containment,” she said. “[With] a more focused idea of where we have issues, we can determine a plan that will be similar to what’s already being done, along with potentially additional inspection points and de-contamination stations.”

Reporter Sam Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.