Zebra mussels found at Smithville Lake, treatment pending

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Published on: Jul. 19, 2010

SMITHVILLE Mo – The Missouri Department of Conservation (MDC) is working with Clay County Parks & Recreation, the City of Smithville and the U.S. Army Corps of Engineers (USACE) to investigate the recent discovery of zebra mussels in a cove of Smithville Lake and to try to prevent the spread of the invasive species in the lake.

MDC Fisheries staff discovered the zebra mussels on a private boat lift during a swimming inspection of the Camp Branch Marina on June 28. The lift was removed from the water and Conservation Agent Scott Stephens is investigating the incident.

According to the Missouri Wildlife Code, it is illegal to transport prohibited species, which include zebra mussels, into, out of or within the state.

MDC Fisheries Management Biologist Scott Ryan said that Conservation staff are continuing to inspect the waters around the dock where the mussels were found for additional signs of infestation. Staff will also conduct long-term monitoring of the entire lake for adult zebra mussels and larvae (veligers).

Adult zebra mussels are dime- to quarter-sized. Although there is a great deal of variation, their shells often have black and white zigzag markings. They attach to solid objects and gather food by filtering tiny plants and animals from the surrounding water. Each female can produce up to a million offspring a year.

The zebra mussel is native to Eurasia. It hitched a ride to North America in the 1980s, arriving in the Great Lakes in the ballast tanks of oceangoing ships. Since then, the thumbnail-sized invader has leapfrogged across much of the continent on commercial and pleasure boats, whose owners unwittingly transport the mollusks when trailering boats from one body of water to another.

Zebra mussels have already infested numerous lakes, rivers and streams in Missouri and Kansas. Missouri infestations have been found in sections of the Mississippi, Missouri and Osage rivers, including the Kansas City and Chamois areas. Lake of the Ozarks has dozens of infested sites. The pests have also turned up in Lake Taneycomo, Bull Shoals Lake and Pomme de Terre Lake. Kansas infestations near Smithville include Perry Reservoir and Milford Lake.

MDC Invasive Species Coordinator Tim Banek emphasizes that zebra mussels pose a threat to both Missouri’s ecology as well as the state’s economy.

“They compete with newly hatched native fish and other animals for food, making them a potential threat to the Show-Me State’s lucrative sportfishing industry,” said Banek. “Their habit of attaching themselves to any solid object dooms native mussels, which can be smothered by dense encrustations of the invaders. Some lakes and streams have experienced ecological changes that have altered entire aquatic communities.”

He added that heavy zebra mussel infestations can weigh down docks, buoys and other marine equipment.

“Infestations on boat hulls increase water drag, leading to higher fuel and maintenance costs,” he explained. “They can clog marine engines’ cooling systems, creating a danger of damage due to overheating. Zebra mussels also drive up utility bills by clogging water intakes of public and private utilities. Treatment of heavy infestations at public and private utilities can cost millions of dollars.”

He added that boaters play a vital role in preventing the spread of zebra mussels and three simple things to remember are, “Clean. Drain. Dry.”

• Clean – Remove all plants, animals and mud, and thoroughly wash everything, especially live wells, crevices and other hidden areas. Wash boat bilges, trailers, motor drive units and live wells with hot water at least 104 degrees. Most commercial car washers meet this standard.

• Drain – Eliminate all water before leaving the area, including live wells, bilge and engine cooling water.

• Dry – Allow boats and other equipment to dry in the sun at least five days before launching in other waters.

MDC, Clay County Parks, the City and the USACE are coordinating efforts to destroy any zebra mussels remaining in the marina cove using an algaecide. This is a chemical treatment commonly used to kill algae. It contains copper, which is toxic to zebra mussels.

Ryan explained that the algaecide should not cause any extensive damage to other aquatic species. He added that a treatment date has not yet been determined, but estimates it occurring in early August.

“We do not expect a significant fish kill as a result of the treatment,” explained Ryan. He added that the county parks department, which operates the marina, will collect and dispose of any dead fish that may appear.

He added that, as a precaution, MDC staff will patrol the cove with a “shocker” boat to electrically stun and remove larger game fish before the chemical application.

Banek noted that the MDC will use zebra mussels taken from Lake of the Ozarks to measure the effectiveness of the chemical treatment. The mussels will be placed in fish tanks on shore and treated lake water will be added.

Marvin Boyer of the USACE, which owns the lake, said that there would be no smell associated with the treatment, but there may be a brief blue tint to the water. He added that the manufacturer’s information about the chemicals to be used indicates there should be no adverse reactions to boaters, skiers or swimmers, such as eye or skin irritation. The chemicals will not harm boats or equipment.

The City of Smithville Water Department is involved in the effort and stated that drinking water will not be affected by the algaecide used to treat the infestation.

For more information on zebra mussels and other invasive species, visit www.missouriconservation.org.

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