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Invasive zebra mussels in Lake Sharpe, spreading up Missouri

Zebra mussels were first found in South Dakota in Lewis and Clark Lake in 2015. On July 12, the South Dakota Department of Game, Fish and Parks confirmed the aquatic invasive species, or AIS, has spread to lower Lake Sharpe.
According to South Dakota Game, Fish and Parks, zebra mussels are small clams usually measuring less than an inch in size up to two inches long. These mussels may seem harmless in appearance, but zebra mussels are known to cause irreparable damage to the ecosystems they invade over time.
Zebra mussels are native to the Black and Caspian seas in Eastern Europe and can be easily transported to new bodies of water in any water remaining anywhere on a boat, bait container, or fishing gear. This is especially likely when the mussel is in its larval state, when it may float in the water for up to a month. Once a mussel has fully developed, it can live for four to five years.
Senior biologist and AIS coordinator for South Dakota Game Fish and Parks, Mike Smith, said the mussels will likely appear in Lake Oahe in the future.
“Zebra mussels are notorious for spreading quickly,” Smith said. “There is high boat traffic between Lake Sharpe and Lake Oahe, so there’s a high chance they will continue to spread.”
According to Smith, the infestation in Lake Sharpe is expected to take five years before it’s wide spread. He said two-dozen zebra mussels had been found in lower Lake Sharpe but that thousands more could be elsewhere.
They can attach to any hard surface and form dense colonies that can clog dam intakes, water supply pipes, irrigation pipes, boat docks and motors, and even alter water quality. Their striped shells are also very sharp and wash up on shorelines in large numbers, posing a danger to swimmers and limiting the use of infested beaches.
Zebra mussels also have a huge appetite and eat the plankton that many native species of fish also feed on.
Despite the negative impacts of zebra mussels, there’s no need to panic for our favorite fishing spots at this point.
“They are likely not to negatively impact fishing,” Smith said. Major problems will be seen most likely in city water systems and agriculture.
There’s little that South Dakota Game, Fish and Parks can do, even at this early stage, to remove the infestation from Lake Sharpe or ensure Lake Oahe won’t be invaded by zebra mussels. As South Dakotans, it’s our responsibility to slow the spread as best we can.
It’s South Dakota law to remove all drain plugs, live wells and bait wells on a boat, trailer and any other watercraft except when in the boat ramp parking lot or when the craft is being launched or loaded. This prevents the spread of zebra mussel larvae.
Smith also recommends power washing boats as much as possible. Letting a boat dry in the sun for three to four days between trips can also help remove any invasive species that may remain following an excursion in zebra mussel infested waters.
“We have rules in place. They can’t stop the spread, but they can slow it,” Smith said. He stressed that zebra mussels in Lake Sharpe aren’t anything to panic about but that the spread of invasive species should be taken very seriously by anyone who boats or fishes.