CASPER, Wyo. — Wyoming is one of the only states where invasive quagga and zebra mussels haven’t been discovered, thanks in part to inspections at aquatic invasive species check stations.
Check stations discovered mussels on a total of 58 boats during 2022, the Wyoming Game and Fish Department said on Monday. In 2021, check stations found 54 boats with mussels, and in 2020, 22 boats were found with mussels.
When boaters come across check stations, inspectors first determine whether a boat is considered low-risk or high-risk for carrying invasive species, according to Game and Fish.
“If the watercraft is deemed low-risk, the watercraft owner will be provided informational materials, the watercraft will be briefly inspected, and allowed to launch,” Game and Fish explained. “A watercraft deemed high risk will need to undergo a more thorough inspection. High-risk watercraft may include those that last operated their watercraft in a state with waters known to have invasive mussels, or watercraft with a large amount of standing water which could harbor larval mussels.”
High-risk inspections increased to 4,747 out of 65,567 total inspections in 2022 compared with 4,187 high-risk inspections out of 68,140 total inspections in 2021, according to Game and Fish. The rise in high-risk inspections is largely due to the discovery of zebra mussels in Pactola, a reservoir in South Dakota just 27 miles from the Wyoming border, according to Josh Leonard, Game and Fish aquatic invasive species coordinator.
“It does not surprise me that those numbers have gone up due to the increased risk we’re seeing every year with more waters becoming positive for mussels and closer to our borders,” Leonard said. “It also highlights how effective collaboration with other agencies can be.”
The discovery of zebra mussels in Pactola Reservoir led Game and Fish to implement new restrictions at Keyhole and Glendo Reservoirs in Wyoming, requiring all boats to undergo inspections prior to launching.
In terms of individual check stations, the one at the Evanston port of entry was the busiest in 2022, with 20,422 boats inspected, according to Game and Fish. There were 2,590 high-risk inspections, 369 boat decontaminations conducted and 51 boats found with mussels at the Evanston port of entry check station. Glendo saw the second highest total number of inspections with 8,052 in 2022.
“AIS check stations are regarded as the first line of defense against invasives entering the state or being spread between Wyoming’s waters,” Game and Fish said. “Those range from invasive plants like curly pondweed, which Wyoming does have, to species that the state has managed to keep out, like Asian carp and zebra or quagga mussels.
“In Wyoming the law requires any watercraft transported into the state from March 1 through Nov. 30 must undergo a mandatory inspection by an authorized inspector prior to launching. Any watercraft that has been in a water infested with zebra/quagga mussels within the last 30 days is required to undergo a mandatory inspection by an authorized inspector prior to launching during all months of the year. All watercraft must stop at any open watercraft check station on their route of travel, even if not intending to launch in Wyoming.”
Game and Fish is evaluating its inspection protocols over the winter before the 2023 boating season, the department noted.