No Evidence Of Invasive Mussels After Divers Scour Tiber Reservoir

Aug 9, 2017

Scuba divers from the U.S. Fish and Wildlife Service have spent the past three days in north-central Montana, scouring the waters of Tiber Dam for any signs of aquatic invasive mussels.

Last October, a juvenile mussel was found in a water sample from Tiber Reservoir by the Bureau of Reclamation, and suspicious samples were discovered in Canyon Ferry Reservoir, near Townsend. Since then, the state has ramped up its efforts to stave off a potentially destructive infestation of non-native quaqqa and zebra mussels.

MontanaPBS producer Beth Saboe who was at Tiber Dam earlier this week with the divers joined us with an update.

Eric Whitney: Beth, thanks for joining us on Montana Public Radio.

Beth Saboe: Thanks for having me.

Whitney: Why were these scuba divers brought in, and what were they looking for?

Saboe: This team of five divers was brought in by the request of Montana Fish, Wildlife & Parks to search underwater for visual or tactile confirmation of adult mussels. Tiber Reservoir was the first water body in the state to ever test positive for quagga or zebra mussels. A juvenile mussel, or "veliger," was found last fall, so state officials are trying to determine if an adult population has been established.

Now the divers — there were three women and two men — they were all federal wildlife officers from Montana, Wyoming and South Dakota, and over the course of the past three days, they spent several hours scouring the rock face of Tiber Dam. Zebra and quagga mussels like to attache to hard surfaces, so that's why they were focusing on the dam face. And so, the divers were there to get visual confirmation of these adult mussels, and before leaving shore, wildlife officer Deb Goeb showed the team how to collect what they call a "scrape specimen," if they were found.

"So, it's on a surface, whether it's face up like this, or underneath a rock, or sideways — again, you're not going to be able to pull it off, not with your fingers, they attach like little mighty mouses on there. Put that on there, and very quickly, that [scraping sound]. You'll scrape it off, and if it's on this kind of a surface you have to carefully lift up and get 'er in there."

Divers with MontanaFWP & USFWS go over what to do if they get visual confirmation of quagga and or zebra mussels at Tiber Reservoir.
Credit Beth Saboe

Whitney: Did they find any signs of an infestation?

Saboe: The good news is that, no, they did not see any evidence of adult mussels in Tiber. Deb told me she did find a rusty old pipe underwater — which is prime habitat for these mussels because they are particularly fond of attaching to metal — but it was mussel free, which she took to be a very good sign.

Whitney: What's the next step for the state in the fight against these invasive species? Are there plans for more dives at Tiber or Canyon Ferry Reservoir?

Saboe: There aren't any more dives scheduled that I"m aware of. Montana FWP officials are understandably pleased that no mussels were found, and will continue to test water samples at each reservoir along with a number of other water bodies across the state. Of course, if any future samples were to test positive for veligers [juvenile mussels] or larvae, then divers might be used again. But, overall, FWP is really putting a lot of emphasis on educating boaters about keeping their boats clean, drained and dry; and running the various inspection stations around the state to check watercraft for mussels and decontaminate them if needed.

Whitney: Beth Saboe with MontanaPBS, thanks for joining us.

Saboe: Thanks for having me.