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Zebra Mussels take over Lewis and Clark Reservoir

by Friends of Lake Sakakawea

Zebra mussels abound in SD
Pierre Capitol Journal

MOBRIDGE — The state Game, Fish and Parks Commission learned Friday that zebra mussels have quickly overtaken Lewis and Clark Reservoir on the Missouri River near Yankton and the invaders nearly found their way into Belle Fourche Reservoir last month aboard a dredging company’s barges.

State fishery director John Lott said some GF&P employees have been inspecting and disinfecting boats when they come out of the water at Lewis and Clark Reservoir so the zebra mussels aren’t carried to other waters of South Dakota.
He said there are more than 200 boats in the Lewis and Clark marina and there needs to be an effort to help disinfect boats.

Zebra mussels were found in the river there in the summer of 2015 and the infestation was found much more heavily this year in the marina, according to Lott.
Last weekend seven boats were disinfected when they came out. The rush will come now because boats must be out of the marina by Oct. 15. GF&P crews helped last weekend and will be there again this weekend. Lott said the marina operator is assisting boaters too.

Lott showed the commission a photo of the pile of mussels taken off boats last Sunday. He said 85 percent of the boats stored in the water have adult zebra mussels this year, but boats stored on lifts out of the water don’t have adults.

He showed a photo of zebra mussels crowded into one boat’s lower drivetrain unit. GF&P staff have learned there’s no way to complete decontaminate a boat that has been stored in the water. He said the drivetrains need to be taken apart and cleaned out.

Lott said he assumes the zebra mussels are proving a problem for irrigators who pump water from the reservoir.

At Belle Fourche Reservoir, dredging equipment that last worked at Lake Superior turned out to be carrying zebra mussels. Lott said the barges were shipped to Rapid City for power-washing and cleaning with chlorine disinfectants.

“There certainly was a potential introduction here that was averted. It serves as a great case history for the public how these things can happen,” Lott said.

Commissioner Scott Phillips of rural New Underwood praised the results. “Great work on averting a crisis in that part of the state. We need to be eternally vigilant.”
Commissioner Barry Jensen of White River asked what happens to a local boater. Lott responded that Belle Fourche was “a perfect example that we didn’t have a mechanism in place to deal with it.”

Lott said GF&P shouldn’t have the responsibility to provide decontamination equipment but a proposed rule would allow the agency to be part of selecting service providers. He said the invasive species work group is looking at the issue.
Lott said there has to be a mechanism for a boat owner to deal with zebra mussels. “That would be at their expense,” Lott said. “No way we would have the resources, especially when we start talking about Lewis and Clark marina, to start doing it ourselves.”

He said the protocol would be “a challenge” and he had “no idea” of the cost for cleaning the barges.

Commissioner Jim Spies of Watertown said: “We’re talking a monumental amount of money. It’s off the charts… I don’t know where we’re going with this. To wrap our hands around this is just a monumental task.”

For Lewis and Clark Reservoir, commissioner Gary Jensen of Rapid City asked if Legislature should provide money.

Lott said GFP has to figure out its plan first. He said the objective first remains stopping spread from Lewis and Clark to other waters. Lott said the potential of zebra mussels infecting other waters of South Dakota could remain even if millions of dollars were spent.

Boat plug regulations that took effect in the past year seem to work for day users but the challenge is boats moored in the water for periods of time, according to Lott.

“Right now I don’t know if we could take to the Legislature a plan for how to stop this no matter how much money you threw at it,” Lott said. “I don’t know if money or more manpower is the answer.”

The U.S. Army Corps of Engineers hasn’t issued any official information to GFP about problems at the Angostura Reservoir’s dam because of quagga mussels, another invasive species, but rumors have been heard, Lott said.

He said mussels in the powerhouse would affect electricity production. “For us as a state that’s a concern for us,” he said. Using emergency spillways at dams to relieve water in the fall to meet downstream navigation on the Missouri River creates new challenges for river management, Lott said.

“We might have to include boat-cleaning stations to our fish-cleaning project,” said Cathy Peterson of Salem, the commission’s chairwoman. Replied Lott, “That might have to be something we talk about.”

Mark Ohm, a GFP regional wildlife supervisor stationed at Mobridge, said GFP staff became more aggressive about checking boats when they leave the Missouri River because compliance with the draining regulations was weak.

Ohm said 121 citations were issued since July 1. The most common violation was people didn’t pull the drain plugs on their boat hulls, meaning their boats could be carrying water and possibly invasive species in the water.