Zebra mussels return to Rathbun Lake

By SCOTT NILES Courier staff writer

CENTERVILLE — Concerns over Zebra mussels have been raised again by Rathbun Lake and Iowa Department of Natural Resources officials after a boat owner spotted the unwanted species.

The 1995 Silverton Cabin Cruiser was nearing the completion of its 940-mile journey from Lake Ponchartrain, La. to Lake Rathbun on May 29. The boat owner noticed some kind of shell life stuck to the boat and contacted lake officials — the Zebra mussels were on the hull.

“We want to commend the boat owner; he is the reason we caught this. That is what we want,” said Mark Flammang, Iowa DNR fisheries biologist.

He said the DNR and Army Corps of Engineers have made several attempts to educate the public as to why this is serious.

“What is kind of rewarding about this is that the owner of the boat did exactly what we want people to do. He read the materials and let us know and said, ‘Hey I think I may have these on my boat,’” Flammang said.

The owner found what he thought were Z`ebra mussels near the transom around the rudder and trim tabs. He stopped the boat from being launched and had a marina employee call the local DNR office. There were an estimated 30 to 40 mussels attached to the boat.

“It isn’t just large boats you can find them on. Larva which are microscopic can be in any boat with water in and can survive,” Flammang said. “If you are coming from a lake or river where these are present, you need to make sure and let the boat dry out. If a boat is dry for at least five days, that will generally kill them.

“We are working with the marinas at Lake Rathbun. When they find these adults on these large boats, they are instructed to contact me and I can direct them to what needs to be done in order to fix the issue.”

Flammang said zebra mussels can cause a number of problems for the lakes and streams they populate.

“You need to keep in mind Rathbun Lake is important to a whole lot of people for many reasons: Recreational boaters, anglers and it also provides water for 60,000 people in Iowa and Northeast Missouri. About 50 million fish are produced here for stocking all around the state. Zebra mussels have the ability to put all that in jeopardy,” he said.

It has not been determined if zebra mussels have established a population in the lake as a result of being introduced by a previous boat in 2007. The Iowa DNR and U.S. Army Corps of Engineers are monitoring areas around the lake looking for the presence of juvenile and adult zebra mussels.

In areas where zebra mussels have become established, like the Great Lakes, there has been a widespread decline in fish population and angling quality.

“Zebra mussels can also cause severe damage to foul boat hulls and motors. They tend to cover boats and multiple rapidly. Another danger is when their shells wash up on the beach and cut people’s feet. They cause tremendous damage to water bodies in all ways,” Flammang said.

The real economic concern is that the mussels will jeopardize Rathbun Regional Water Association’s ability to provide water to this part of the state and could shut down operations at the fish hatchery.

“So it is a big deal,” Flammang said.

One zebra mussel is able to filter a liter of water a day, eliminating plankton and other subspecies that many aquamarine life survive on. Therefore, an abundance of the mussels could mean the extinction of several types of fish in the lake, officials said.

Zebra mussels are native to the Caspian Sea region of Asia and were believed to be introduced from ballast water into Lake Erie in 1988.

“We will be doing some survey work throughout the year. This is something we are committed to for the long haul, for a number of years. We just want to protect our waters,” Flammang said.

Scott Niles can be reached at (641) 683-5360 or via e-mail at sjniles@mchsi.com.