Invasive New Zealand mudsnails, curly pondweed found in Wyoming's Flaming Gorge - Casper, WY Oil City News
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Invasive New Zealand mudsnails, curly pondweed found in Wyoming’s Flaming Gorge

Flaming Gorge Recreation Area (Shutterstock)

CASPER, Wyo. — The Wyoming Game and Fish Department has confirmed the presence of two invasive aquatic species in Flaming Gorge Reservoir, according to a press release from the department shared by SweetwaterNOW on Tuesday.

New Zealand mudsnails have been documented above the Flaming Gorge dam, making this the first time the invasive species has been confirmed at the reservoir. Game and Fish confirmed the presence of the mudsnails after receiving tips from members of the public.

An angler reported seeing curly pondweed in mid-June south of the Anvil Draw boat launch, according to Game and Fish. That angler also found a clump of the invasive pondweed floating in the south end of Big Bend.

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“Upon investigation, more curly pondweed was found north of Brinegars Ferry boat launch, as well as mudsnails,” Game and Fish said.

Curly pondweed had been detected at Flaming Gorge back in 1979 and 1980 but has not been detected since that time.

“We’re disappointed to verify the presence of curly pondweed and mudsnails in Flaming Gorge,” Green River Regional Fisheries Supervisor Robb Keith said. “This discovery exemplifies the need for diligence from all watercraft users to stop at AIS (Aquatic Invasive Species) check stations and follow Clean, Drain and Dry procedures to keep all AIS 一 even those already found in Wyoming 一 from spreading.”

“Thank you for any and all reports of AIS sightings. These tips are crucial to our AIS response. Because of this information, we are able to act quickly to verify the presence of AIS to contain the spread.”

Curly pondweed is a species native to Eurasia, Africa and Australia that was introduced to the United States in the mid-1800s, according to Game and Fish.

“It is now found throughout the continental U.S,” the release states. “In Wyoming, curly pondweed has been found in Boysen, Deaver, and Keyhole reservoirs, Lake DeSmet, Wheatland Reservoir #3, West Newton Lake and in the Miracle Mile (North Platte River between Kortes and Pathfinder reservoirs).”

“Curly pondweed reproduces by seed or leaf fragments, which can be easily transported in mud or water and has the potential to form dense mats of vegetation, negatively impacting water-based recreation. It is typically introduced into new areas accidentally and as an ornamental plant.”

New Zealand mudsnails in the United States were first discovered in Idaho in the Snake River in 1987.

“They have spread to other western states, including Wyoming, where they are found in Lake Cameahwait, and the Bighorn, Shoshone, Snake, Salt and North Platte rivers,” Game and Fish says.

Green River AIS Specialist Eric Hansen added that “because they reproduce asexually, these snails can be easily spread and produce a new population. They seal themselves off allowing them to survive for extended periods of time out of water, or even through the digestive system of birds and fish.”

The department will continue to monitor for both species and try to determine how widespread their populations are in Flaming Gorge and surrounding areas.  

Game and Fish said that there are currently no changes to rules for boaters or others recreating in Flaming Gorge.

“To help limit the spread of these aquatic invasive species, the Game and Fish asks recreationists to Clean, Drain and Dry their watercraft after every use and to take an extra minute to ensure they are not transporting any vegetation or debris on their watercraft, equipment or trailers,” the department said. “Boaters are reminded that Game and Fish regulations require the immediate removal of all visible vegetation from watercraft and trailers when leaving waters of this state.”