Critics say South Dakota too lax in zebra mussel prevention

Confirmed finding last summer of zebra mussels in Pactola Reservoir has sparked greater scrutiny of South Dakota’s efforts to protect bodies of water from aquatic invasive species

A roadside inspection station in Wyoming makes sure boaters are following regulations related to zebra mussels and other invasive species. Boaters are required to clean off boats and trailers, drain live wells and bait buckets and dry off boats and trailers before reintroducing them to a body of water.
Photo Courtesy Wyoming Game and Fish Department
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The confirmed finding last summer of zebra mussels in Pactola Reservoir – 15 miles west of Rapid City in the Black Hills National Forest – has sparked greater scrutiny of South Dakota’s efforts to protect bodies of water from aquatic invasive species, which spread exponentially and can negatively impact ecosystems, water intakes, fisheries and beaches.

Zebra mussels, snail-like mollusks that reproduce rapidly and move from lake to lake by attaching to boats or microscopically in ballast tanks and live wells, were first discovered in South Dakota at Lewis and Clark Reservoir in 2015 and have now infested 12 bodies of water, including Lake Sharpe and Lake Francis Case on the Missouri River.

That high speed of spread has led advocacy groups and some state legislators to call for more aggressive mitigation from the South Dakota Game, Fish & Parks Department and Gov. Kristi Noem. The governor signed a law in 2020 to broaden GFP enforcement authority regarding invasive species but has been largely quiet on the issue the past two legislative sessions.

A recreational boater in Wyoming goes through inspection and decontamination protocols in order to launch his boat. Wyoming has intensified its mitigation efforts after Pactola Reservoir in western South Dakota was infested with zebra mussels in the summer of 2022.
Photo Courtesy Wyoming Game and Fish Department

Now, western neighboring states such as Wyoming and Montana are sounding the alarm on aquatic invasive species (AIS) and calling out South Dakota’s relative lack of resources and staffing to carry out boat inspections, decontamination, water testing and other preventative methods. Some worry that South Dakota has been too slow to contain the spread of adult zebra mussels and juveniles known as veligers, free-swimming larvae that can spread through water currents. Female zebra mussels can release as many as 1 million eggs per year, according to the U.S. Fish and Wildlife Service.

“We have a new threat right on our doorstep,” Josh Leonard, the Wyoming AIS coordinator, told News Watch. “Before Pactola was infested, the closest zebra mussel population was the Missouri River area. Being 27 miles away from our border versus a couple hundred miles away has heightened the threat to our state. If South Dakota was able to do more at Pactola, we might not have to be doing as much here.”


Alan Osterland, Wyoming chief of fisheries, was even more direct when addressing the Wyoming Game and Fish Commission this past September. “The [South Dakota] response, in our opinion, has been hands off,” he said.

The South Dakota AIS program budget for 2021 was $538,000, which includes federal grant money through the U.S. Fish and Wildlife Service and the Bureau of Reclamation, which oversees dams, power plants and canals in the western states. Wyoming has an annual AIS budget of $1.3 million, paid for partly by fees for AIS decals, which cost $10 for motorized watercraft registered in Wyoming and $30 for motorized watercraft registered in other states.

Dan Loveland of the South Dakota Lakes and Streams Association holds up zebra mussels found on his property at Lake Pickerel in the summer of 2021. The snail-like mollusks reproduce rapidly and move from lake to lake by attaching to boats or microscopically in ballast tanks and live wells.
Photo Courtesy of Dan Loveland

Montana has invested about $5 million a year to fund water sampling and boat check stations to protect the state’s lakes and reservoirs from infestation. The state plans to adjust inspection station operations in 2022 “to address boat traffic from the Black Hills” now that zebra mussels have migrated west in South Dakota.

Minnesota, which first observed zebra mussels in 1989 in the Duluth/Superior harbor, spends about $10 million each year on AIS prevention and containment efforts, with the money disbursed to counties to formulate their own strategies.

South Dakota doesn’t have a dedicated state funding source for its AIS program, relying on federal grants and partnerships with community groups, in addition to coordinating with state agencies such as the Department of Transportation and the Department of Public Safety.

GFP Secretary Kevin Robling and AIS Coordinator Tanner Davis have enacted a strategy of public outreach and education, using signage and marketing to convey a message of “Clean, Drain, Dry” to recreational boaters. That slogan refers to cleaning off boats and trailers, draining live wells and bait buckets and drying off boats and trailers before reintroducing them to a body of water to prevent the spread of zebra mussels.

The GFP strategic management plan notes that there are nearly 10,000 waterbodies and roughly 500 boat ramps statewide and the “geographic size and complexity of South Dakota’s aquatic resources make containment efforts challenging.” Davis told the GFP Commission on Dec. 9 that the department saw 96% plug compliance in 2022 and that the goal is to educate the other 4% and use enforcement measures when needed.

Zebra mussels cluster around the base and wheels of a dock pulled from the water at Lake Pickerel in 2021. The lake is one of 12 in South Dakota that have been infested by aquatic invasive species.
Photo Courtesy of Dan Loveland

South Dakota GFP officials note the difficulty of finding enough seasonal employees and college interns to fill AIS boat inspection positions throughout the state. South Dakota conducted 18,500 inspections in 2022, far fewer than Minnesota (540,000), Montana (90,000) and Wyoming (65,000), but more than Nebraska (6,600) and North Dakota (5,000).


When asked by legislators during a Government Operations and Audit Committee meeting in October 2022 whether GFP would benefit from more stringent laws or more state funding for AIS programs, Robling replied that things are “working quite well” and that his department is “adamantly trying to slow the spread of aquatic invasive species” with public messaging.

“We feel that we have the necessary statutes in place at this time, so the answer to your question would be no,” said Robling, who became Secretary of GFP in December 2020. “We feel like we have the financial resources and staffing, once we fill those positions that we are hoping to fill. Right now, though, the workforce issue is a challenge, no question about it.”

Robling’s summary didn’t sit well with Sen. Reynold Nesiba, D-Sioux Falls, a member of GOAC and the Senate Appropriations Committee, who wants to see more done to prevent zebra mussels from harming South Dakota waters and infrastructure such as intakes and irrigation systems.

Zebra mussels, seen here adhering to a boat lift at Lake Pickerel, spread exponentially and can negatively impact ecosystems, water intakes, fisheries and beaches.
Photo Courtesy of Dan Loveland

Nesiba said containment is crucial while scientific research is done to determine if impacted lakes can be treated to reduce the ecological impact of zebra mussels and other invasive

species such as Eurasian water milfoil, curly leaf pondweed and starry stonewort. Early detection is a top priority in Montana, which uses techniques such as eDNA testing to pick up an organism’s cellular traces in the water column.

“I think there is a sense from Game, Fish and Parks that resistance is futile, and I think they’re wrong about that,” Nesiba told News Watch. “They aren’t communicating with community groups that care deeply about this issue and they’re doing far less than other states. What’s missing is the political will and leadership to see this as a problem that can be mitigated, and I remain hopeful that the governor is going to step up and do more about this.”

South Dakota has so far resisted calls for an economic impact study to determine potential costs to the state if the proliferation worsens, as expected. The fact that the Pactola Reservoir is instrumental for irrigation purposes and for providing water for municipal and industrial users in Rapid City is the newest cause for concern about potential future costs. Zebra mussels can choke off water pipelines and foul irrigation channels, leading to major maintenance costs.

The Minnesota Invasive Species Council released a report in 2019 that estimated an annual economic cost of $230 million in mitigation expenses and lost revenue if zebra mussels were to infest the state’s lakes, a number that was viewed as conservative because it only considered the cost to affected stakeholders and not general state resources.


Pam Bogart of Hot Springs is shown working as an Aquatic Invasive Species watercraft inspector for South Dakota Game, Fish and Parks during the summer of 2021.
Photo Courtesy of Pam Bogart

Gov. Noem did not respond to questions sent by News Watch about her stance on the AIS issue and she has declined meeting requests from the citizen-led South Dakota Lakes and Streams Association, of which former Republican state senator Deb Soholt of Sioux Falls is a board member.

Soholt believes the governor’s recent inattention to the issue is indicative of a state government response that fails to weigh the potential impact of invasive species on tourism, outdoor recreation, water quality, irrigation and lake and river ecosystems.

“I would hate for her legacy to be the governor who lost control of South Dakota waters under her watch,” said Soholt.

EDITOR'S NOTE: This article was produced by South Dakota News Watch, a non-profit journalism organization located online at

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