The Montana aquatic invasive species (AIS) battle has come a long way in a short period of time on the monumental journey to the future of maintaining a zebra and quagga mussel-free Columbia River Basin. It is perhaps the most glaring, monumental and daunting environmental hazard facing the citizens of Montana and the Pacific Northwest as well as all citizens of America — they all have a stake in the environmental health of this corner of the nation. It is a never-ending battle that requires eternal vigilance.
The Confederated Salish and Kootenai Tribes, as owner of the southern half of Flathead Lake, have a huge stake in keeping the Flathead River Basin mussel free. And they have been vigilant at the forefront of the mussel infestation prevention with its Natural Resource Department’s AIS program with its education programs and watercraft inspection stations.
In the latest statistics released last week by the Montana Fish, Wildlife and Parks, its Aquatic Invasive Species (AIS) Program’s watercraft inspection stations sieve has snared 14 quagga or zebra mussel fouled watercraft out of 104,000 statewide inspections at the 45 inspection stations in the state. There were 15,899 high-risk boats inspected that were last launched in states with known aquatic invasive species infestation.
One of the fouled watercraft was intercepted at the Ravalli inspection station staffed by the CSKT. That happened on July 28 when the Ravalli crew found the invasive mussels on a kayak that was last launched in Lake Superior.
The Clearwater Junction watercraft station conducted the most inspections with 20,200. The CSKT managed Ravalli station was next with 13,100 and its Plains station conducted 3,100 inspections. The Browning station managed by the Blackfeet Nation inspected 3,700 watercraft. The Flathead and Blackfeet nations are located at strategic choke points of entry into waterways in the Columbia River Basin.
The CSKT Ravalli watercraft inspection station will be operated until Oct. 15. The Ravalli station opened March 15, making its seven month operation the longest in the state. The Plains inspection station closed Sept. 15; it opened May 11.
In November 2016, Montana Department of Natural Resources and Conservation officials announced the first documented presence of zebra and quagga mussels in Montana, after positive tests at sites in the Missouri River system in Tiber Reservoir, and “suspect” detections in Canyon Ferry Reservoir.
In the last three years the inspections have ramped up steadily. In 2016 there were 39,000 watercraft inspections with five AIS detected; in 2017 there were 80,000 inspections with 12 AIS detected; and in 2018 there were 99,000 with 12 AIS detected. Heretofore this year more than 1,500 early detection samples have been analyzed for invasive mussel larvae. To date, no invasive mussel larvae have been detected this season. Sampling and analysis will be ongoing through the fall.
The Flathead Lake Biological Station (FLBS) in partnership with FWP conducted an intensive survey in areas of Tiber Reservoir in early August. The survey utilized both molecular (eDNA) and microscopy methods in an attempt to get a better picture of whether invasive mussels are still in Tiber Reservoir and where they are located. No evidence of invasive mussels was found in Tiber in 2018. Forty-five plankton tow samples have been collected and analyzed so far for Tiber this season and no mussel veligers have been detected. In August the FLBS conducted eDNA testing for mussels in Tiber Reservoir; no evidence of mussel DNA was detected.
A 2018 report by the Montana Department of Natural Resources and Conservation released in January estimated the costs of a zebra and quagga mussel infestation at up to $234 million per year to the state economy.
Zebra and quagga mussels are freshwater, bivalve mollusks that typically have a dark and white (zebra-like) pattern on their shells. They are native to Eurasia and are alien to North America. Both mussels species are usually about an inch or less long, but may be larger.
Until the mid 1980s there were no zebra mussels in North America. That changed when they were inadvertently introduced into waters near the Great Lakes region. It is suspected that zebra mussels hitched a ride in ballast water tanks of commercial ships.
Zebra/Quagga Mussels negatively impact aquatic ecosystems, harming native organisms. They out-compete other filter feeders, starving them. They adhere to all hard surfaces, including the shells of native mussels, turtles, and crustaceans. Zebra and quagga mussels actively feed on green-algae and may increase the proportion of foul-smelling blue-green algae in water systems.