LAK closed to boats, mussel creeps closer

Alexis Barker

Alexis Barker

NLJ News Editor


Zebra mussels are slowly but surely creeping closer to the Wyoming border, sparking the closure of the LAK reservoir for all boats and watercraft to hopefully prevent the establishment of a population there, according to a July 27 press release from the Wyoming Game and Fish Department. 

The restrictions began on Aug. 1.

“Due to the recent discovery of invasive zebra mussels in Pactola Reservoir in South Dakota’s Black Hills, the Wyoming Game and Fish, in consultation with True Ranches, is closing LAK Reservoir (near) Newcastle to all motorized and non-motorized watercraft for the remainder of 2022,” the release says. 

The LAK is a privately owned reservoir and is accessible to fishers, boaters and swimmers through an access agreement between True Ranches and the department. The reservoir is approximately 122 surface acres fed by Stockade Beaver Creek, department information says. 

“Zebra mussels are an extremely destructive aquatic invasive species,” said Alan Osterland, the Game and Fish chief of fisheries in a March 4, 2021, release. “Once they become established in reservoirs, lakes or even city water systems, they wreak havoc. They remove nutrients from water, clog pipes and waterways, damage boats and out-compete native mussels. Further, in many cases, zebra mussels are impossible to remove and could have costly impacts for Wyoming.” 

According to the same release, zebra mussels are striped and are less than 2 inches. In their immature stage, they can be invisible to the naked eye. The resilient, nearly impossible to eradicate, mussel attaches to any hard surface — such as metal, glass, plastic, stone, wood or rocks — and they are extremely resistant to the cold and a wide array of chemicals. 

In addition to its recreational purpose, the LAK serves as the irrigation reservoir for the ranch. 

And, according to Josh Leonard, Game and Fish AIS coordinator, True Ranches would be directly impacted if the mussels were to establish a population in the LAK. 

“True Ranches would be affected, dealing with it would be a maintenance nightmare,” he said. 

According to in an article dated May 28, 2021, the Montana Department of Natural Resources predicts that a worst-case scenario invasion of the zebra mussels would cost that state an estimated $234 million annually in damages to the state’s economy. 

Congressional researchers estimated that an infestation of zebra mussels in the Great Lakes cost the power industry alone $3.1 billion in the 1993-99 period, with a total economic impact on industries, businesses, and communities of more than $5 billion, according to a 2009 report on prepared for the Idaho Invasive Species Council.

Closer to home, in a recent rapid response plan development, Wyoming Game and Fish predicted that containment at Flaming Gorge in the southwestern part of the state would cost $2 million annually, Leonard said.

He noted that a similar response at the LAK would be less expensive, but the agency is no less concerned. 

The mussels’ presence in Pactola marks the closest population to the Wyoming border and is extra alarming because many boaters frequent waters on both sides of the state line, information from Game and Fish says. 

“Many boaters from South Dakota pop over to Wyoming for the day and vice versa,” Leonard said. “The risk that mussels could spread is the highest it’s ever been.” 

With only 27 miles between Pactola and the Wyoming border, and 62 miles between the two reservoirs, the discovery of the mussels has sparked an aggressive response by Game and Fish. 

“We’re confronting this threat head-on,” Leonard said. “Game and Fish is increasing our diligence to inspect watercraft for mussels and other AIS in northeast Wyoming.”

The restrictions on watercraft use could be temporary, but Leonard said it will be some time before that is known. He noted that discussions about the future of the reservoir’s usage will take place over the next six months between the department and True Ranches. 

According to both Leonard and Reed Moore, the Sheridan Region Aquatic Invasive Species crew specialist, the restrictions are necessary due to the lack of AIS check stations in the area. 

“LAK Reservoir is not the only Wyoming water now facing the threat of accidental AIS introduction, but it is in an area that does not have an AIS check station in the vicinity to inspect or decontaminate watercraft,” Moore said in the July 27 press release.

Placing an AIS check station in the area is a possibility, Leonard said, but it would take discussion between the department, the landowners and the community on the various options. 

“Ultimately it would take a request for us to have a budget increase or for us to reallocate current resources to the program,” he said. “That is a discussion we will have this fall and winter. To see if it is feasible moving forward.”

To prevent the use of the reservoir by watercraft, the department intended to put up signage and a fence to prevent the launch of any watercraft at 8 a.m. on Aug. 1. 

 “It is important that all boaters and anglers take steps to prevent accidentally moving zebra mussels or other invasive species. Clearing, draining and drying watercraft and equipment between waters is the most effective way to prevent moving AIS to new locations,” Moore said in the release.

Leonard added that an invasion of zebra mussels at the LAK would likely lead to a full closure of the reservoir. 

“Getting rid of them (zebra mussels) is nearly impossible, and they quickly move downstream in the water systems. I am guessing if we find them, it probably won’t open up again,” he said. “There would have to be a containment plan if we did, to inspect and decontaminate boats. That is more inconvenient on the boats. I can safely guess that it won’t be opened again.” 

All watercraft transported into Wyoming between March 1 and Nov. 30 are required to undergo mandatory inspection by an authorized person at an AIS inspection station before launching on a Wyoming waterway. Any boater who enters the state and does not encounter a station is responsible for seeking an inspection. 

“The threat is real — and it is here. It’s our top priority to keep mussels out of Wyoming — for our natural resources, recreation and livelihoods,” Leonard said. “We need your help, so please help us protect our state by stopping at our watercraft check stations.”

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