FWP Wraps Up Aquatic Invasive Species Survey Season

Montana Fish, Wildlife & Parks is wrapping up another season surveying for aquatic invasive species (AIS). FWP and partner AIS early detection crews surveyed more than 300 waters around the state, collecting over 2,200 early detection samples, looking for new populations of invasive mussels, snails, clams and aquatic weeds.

AIS early detection crews conducted focused surveys for AIS at all fish hatcheries in the state, assessed Eurasian watermilfoil treatments in Noxon Reservoir and supported a state-wide crayfish survey project. AIS staff worked with a variety of partners on Eurasian watermilfoil eradication in Beaver Lake near Whitefish, fragrant water lily removal in Holland Lake and Asian clam eradication in Lake Elmo in Billings.

New populations of several AIS were identified in the state this year including several snail and plant species. New Zealand mudsnails (Potamopyrgus antipodarum) were identified at three new locations including Beavertail Pond east of Clinton, Mitchell Slough adjacent to the Bitterroot River near Victor and Big Sheep Creek near Dell. This is the first time New Zealand mudsnails have been detected in Montana’s natural water bodies west of the Continental Divide. The tiny mudsnails are often transported to new locations when snails cling to plants, muddy boots or fishing gear.

Invasive red-rim melania snails (Melanoides tuberculatus) were detected in the Gardner River and in a warm spring near Beaverhead Rock State Park. Melania snails were likely introduced through a dumped aquarium tank.

Survey crews identified a new population of curlyleaf pondweed (Potamogeton crispus) in Big Elk Creek near Two Dot in the Musselshell River drainage this year. Curlyleaf pondweed is an invasive aquatic plant that can grow in high densities that obstruct boating and water flow for irrigation.

Surveys are still wrapping up for the year, but no evidence of invasive mussels has been found in the state so far this season. If no evidence of mussels is found in Tiber Reservoir, FWP will evaluate lifting the mandatory inspections requirements for boats exiting the lake. Final sampling results will be completed by the end of October.

These new detections are a reminder to ensure boats, trailers, fishing gear, waders and clothing are always clean and free of mud, plants and vegetation; all water is drained; and boats and gear are thoroughly dry before entering another waterbody. Aquarium pet owners should never dispose of aquarium water, plants or animals into natural waterways.

The public can report sightings of aquatic invasive species to FWP at CleanDrainDryMT.com or call 406-444-2440.