Officials In Dakotas Look To Contain Invasive Zebra Mussels
SIOUX FALLS, S.D. (AP) — An invasive species of mollusks seen sporadically in the Dakotas in past years is establishing a population in two river systems — but state officials hope to prevent the zebra mussels from spreading to other reservoirs.
Zebra mussels of multiple sizes were found recently on boats moored in South Dakota’s Lewis and Clark Lake, a Missouri River reservoir in the southeastern part of the state. The mussels, which clog intake pipes and compete for algae, surely will work their way downstream, but state officials are increasing their boat inspections to prevent the nuisance critters from hitching rides upstream or into other waterways.
The population appears to be exploding in Lewis and Clark Lake since a single mussel was found on a removed dock in November 2014, said Mike Smith, statewide aquatic invasive species coordinator for the South Dakota Game, Fish and Parks Department.
“Before, we just had the one,” Smith said. “Now we know for sure that we have a reproducing population on the lake.”
Last month, North Dakota’s Game and Fish Department found a significant number of zebra mussel larvae called veligers in the Red River north of Wahpeton. Fred Ryckman, the department’s aquatic nuisance species coordinator, said 3- to 4-day-old veligers have been found in several spots along the north-flowing river, suggesting a sizeable adult population.
“What’s surprising is that they went from next to nothing to this year just being tremendously abundant,” Ryckman said.
Zebra mussels originated in Eastern Europe and first appeared in North America in 1988, most likely arriving on a cargo ship traveling into the Great Lakes. The mussels worked their way into the Mississippi River system by escaping into the Illinois River, and migrated into the northeast via the Hudson River, according to the U.S. Geological Survey.
The mollusks can attach to rock, rope, cement and steel pilings and even each other to form colonies. One zebra mussel can lay more than a half-million eggs per spawn, and “mussels born in April or May can already reproduce by the end of the summer,” Smith said.
Zebra mussels can wreak havoc anywhere pump and intake valves reach into the water and can set up colonies inside industrial sized pipes at hydroelectric, nuclear power and public water supply plants. The mussels also mix sharp points into once-smooth recreational beaches, and a large colony of the mollusks can consume enough plankton to hurt the local ecosystem.
South Dakota Game, Fish and Parks Department officials have notified colleagues in Iowa and Nebraska that mussels will likely begin appearing downstream on the Missouri.
But officials are hoping to prevent boaters from inadvertently providing the mussels transportation to upstream Missouri River reservoirs and lakes. Boaters must pull their drain plugs and empty their live wells and bait wells as soon as they pull their boats from the lake, and inspectors are on site to look for attached mussels — ready to pressure-wash boats with 140-degree water if needed.
Those putting boats and personal watercraft into North Dakota’s Red River also must pull their plugs to fully drain the vessels. Anglers fishing the Red had previously been allowed to take bait in buckets of 5 gallons or less, but new regulations prohibit any removal of water from the system.
“Hopefully we can contain this infestation to the Red River,” Ryckman said.
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