Two species of tiny invasive mussels have been wreaking havoc in the Midwest since the 1980s. Now, their range continues to expand in the Mountain West.
The related quagga and zebra mussels are a problem because they clog pipes for agriculture and hydropower, and suck important nutrients out of the water, transforming ecosystems. Estimates from water bodies with infestations put the annual cost of dealing with them at hundreds of millions of dollars. Once the mussels are present, they’re very difficult to get rid of; females can release up to a million eggs a year.
In 2007, quagga mussels were discovered in Lake Mead in Nevada – the first time either species was found west of the Continental Divide. But now, they’ve been detected in every Mountain West state except for Wyoming and New Mexico. Montana is also considered “mussel free” because it hasn’t seen them in more than five years.
Idaho and Colorado, on the other hand, are actively responding to the microscopic larval form of the mussels in major rivers. Idaho attempted to eradicate invasive quagga mussels last year, but they re-emerged in the Snake River in September. Colorado is still searching for the source of just a few zebra mussel larvae found in the Colorado River and a nearby canal in July.
That the juvenile mussels were found in rivers could present unique challenges for containment, said Tom Woolf, the aquatic invasives bureau chief at the Montana Department of Fish, Wildlife and Parks and the chair of the Western Regional Panel on Aquatic Nuisance Species.
“Instead of a discrete lake where you can have certain boat ramps you deal with in a certain area, rivers cover long distances and usually have multiple access points where people can put a boat in the water and potentially bring mussels out with them,” Woolf said.
To Woolf, the recent mussel detections highlight the value of prevention efforts such as making sure boats are not transporting mussels from one body of water to another.
While boat inspection stations, the funding behind them and requirements for boaters vary by state, Woolf said his regional group is brainstorming better ways to reach boaters and emphasize the importance of keeping mussels out.
“As mussels pop up in more places, it gets that much harder to keep them from spreading,” he said.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.
