Zebra Mussels -- a question of 'if' or 'when'
By Russ Oechslin, Journal Correspondent | Posted: Sunday, May 18, 2008
DNR officers Mike Hawkins, Gary Owen, and Bill Maas talk with Iowa Great Lakes Water Safety Council Chairman Phil Petersen (second from right) about the educational billboard placed on Highway 86 in West Okoboji by Gerald and Jo Martin, of Waterloo. (Photo by Russ Oechslin)
WEST OKOBOJI, Iowa -- Depending on who is doing the talking, the question isn't how to keep Zebra Mussels out of Iowa's Great Lakes -- just how long it will take for them to show up.
But one Waterloo couple isn't waiting to find out. Gerald and Jo Martin, who have a summer home on West Lake Okoboji, have invested about $5,000 in a billboard hoping that education might be the key to keeping the invasive species out of the area.
Zebra Mussels have already invaded eastern Iowa, after traveling from the Great Lakes shipping lanes, to the Mississippi River, to Lake Delhi (in Delaware County) and Clear Lake, near Mason City.
The mussels are small clams -- generally about an inch in size -- which attach themselves to any solid object. Native to the Caspian Sea, they first came to North America via transoceanic ships that discharged ballast water into Lake St. Claire, near Detroit.
A Zebra Mussel female can produce in excess of 30,000 eggs. And the generations mature rapidly, making the mollusk difficult to control. Colonies can have from 70,000 to 700,000 mussels per square yard.
Zebra Mussels feed by extracting microscopic plant life from water, robbing native organisms of much needed food sources, while releasing toxins that are then passed on to fish. A single adult mussel can filter a full liter of water each day, every day of its life. It is estimated that the entire volume of the Lake Erie Basin was filtered through Zebra Mussels each day.
Power plants on Lake Erie have experienced 20-30 percent reductions in pumping ability due to the mussels clogging intake pipes.
Control is difficult if not impossible, short of "killing" a body of water and all vegetation and animal alike in the lake.
Billboard: Wash the boat
The Martins' billboard calls for boaters and fishermen to wash their crafts with hot water between uses. That's a first step, says Kim Bogenschutz, the Iowa Department of Natural Resources' Aquatic Invasive Species Coordinator, based in Boone, Iowa.
And "hot" is a matter of definition.
A water temperature of 104 degrees is enough to effectively kill Zebra Mussels -- and is still relatively safe for people, Bogenschutz says. But a 140-degree water temperature is recommended because of Viral Hemorrhagic Septicemia -- VHS -- a virus that affects multiple fish species -- including walleye, blue gill, muskies, and trout -- and can kill them, she adds.
This means cleaning out a boat at a car wash, with high pressure hot water. "Steaming is incredibly effective."
"A high pressure car wash will probably kill immature, microscopic Zebra Mussels. They're pretty fragile and fall apart, because they need oxygen," Bogenschutz said.
The very minimum treatment when pulling a boat out of a lake is to drain the boat, the bilge, live well and bait bucket and let them dry out for a week before going to another body of water.
And, draining the boat should be done at the boat ramp when leaving the lake, not in to a storm sewer which could put any invasive species into another body of water. "Pull the plug and drain the live well. Be very vigilant. And be sure to remove all vegetation."
This should be done every time a boat is removed from a lake, Bogenschutz cautions, "even if you don't think the lake is infected."
Mike Wahl, the DNR's Regional Fisheries Supervisor, who recently served at Clear Lake for 26 years, explains that the DNR "doesn't want to inconvenience the public. But the effect could be devastating."
Wahl agrees the main focus at this point is educating the boating public. "Cleaning out the lower unit of material that isn't even visible to the naked eye -- getting rid of all moisture that the mussels need to live," is important. And it takes five days of drying to kill the organisms.
DNR staffers, Wahl says, flush their boats with bleach. And once the cooling system is flushed with bleach, it is re-flushed with fresh water and allowed to dry. "Air is caustic," he adds.
Wahl praises the local Water Safety Council for its educational efforts. "Anything we can do to get idea out to the general public is helpful."
Martins see a real threat
Gerald Martin says he and his wife are "worried about what we perceive is a real threat." And, he admits, he hasn't seen a lot of action because it takes a lot of manpower to inspect every boat as it enters local waters.
"I don't think people perceive it to be the threat it is -- a change to the ecology and economy -- and recreational opportunities," in the Iowa Great Lakes area.
Martin says "There's a huge urgency." After the fact -- even discounting the problems with the public water supply, swimmers' feet get cut, he adds. "What can we do then?" he asks. "It's too late."
The Martins spend a week or two of each summer in Okoboji "and long weekends when we can," he says. "We'd like to retire up here. We're tired of drive from Waterloo and could solve it by spending more time here. But I don't want a lake full of Zebra Mussels.
"Then there's no solution -- only a dead body of water. The only solution is keeping them out."
"They (the Zebra Mussels) have already filled Lake Michigan. They've removed the food source. Making the water cleaner results in an algae block. And it makes for foul smelling water."
The ideal solution would be to require wash-outs, limit access to only certain boat ramps and inspect each vessel before it goes into the water, Martin suggests. But that, he admits, would be impractical, due to the manpower required.
More pessimistic?
DNR Fisheries Management Biologist Mike Hawkins is less optimistic. Hawkins serves a nine-county area of Northwest Iowa and notes that "Nature finds a way -- she abhors a vacuum."
Hawkins says he believes "any species will spread if it physically can -- good species as well. But an Aquatic Nuisance Species -- an 'exotic' -- can occupy a niche that is not being used for that location."
The biologist likens the spread of the Zebra Mussel to that of Purple Loosestrife -- a terrestrial plant that is an invader spread by birds.
"Zebra Mussels are not regarded as a nuisance in Europe," Hawkins explains, because they are held in check by other native species. "But when a species like that is put into another environment, the species has the ability to become a nuisance because it leaves behind the diseases that had evolved along with it."
A retired school teacher, DNR Enforcement Officer Bill Maas agrees with Hawkins. "It's not a matter of 'if,' but more likely 'when,'" he says. Not trying to dampen the Martins' enthusiasm, which he applauds, Maas suggests trying to fine a natural enemy to nuisance species.
But, true to his teaching background, Maas warns youngsters that Zebra Mussels will cut their feet when they run on the beach and swim in the lakes.
And, Maas also explains that the DNR does schedule its limited staff and volunteers for the busiest times at the area's boat ramps to educate boaters.
"It take public awareness and a lot of communication," he says.
The DNR's Kevin Baskins explains that in a very narrow sense Zebra Mussels would be a good thing in places like East Lake Okoboji and Spirit Lake, which have seen considerable algae over the years due to runoff of chemicals from the surrounding area.
"The Zebra Mussels will clean the water. You'll be able to see the bottom at 10-foot depths.
"But the bad news is all you'll be able to see is mussels."
But one Waterloo couple isn't waiting to find out. Gerald and Jo Martin, who have a summer home on West Lake Okoboji, have invested about $5,000 in a billboard hoping that education might be the key to keeping the invasive species out of the area.
Zebra Mussels have already invaded eastern Iowa, after traveling from the Great Lakes shipping lanes, to the Mississippi River, to Lake Delhi (in Delaware County) and Clear Lake, near Mason City.
The mussels are small clams -- generally about an inch in size -- which attach themselves to any solid object. Native to the Caspian Sea, they first came to North America via transoceanic ships that discharged ballast water into Lake St. Claire, near Detroit.
A Zebra Mussel female can produce in excess of 30,000 eggs. And the generations mature rapidly, making the mollusk difficult to control. Colonies can have from 70,000 to 700,000 mussels per square yard.
Zebra Mussels feed by extracting microscopic plant life from water, robbing native organisms of much needed food sources, while releasing toxins that are then passed on to fish. A single adult mussel can filter a full liter of water each day, every day of its life. It is estimated that the entire volume of the Lake Erie Basin was filtered through Zebra Mussels each day.
Power plants on Lake Erie have experienced 20-30 percent reductions in pumping ability due to the mussels clogging intake pipes.
Control is difficult if not impossible, short of "killing" a body of water and all vegetation and animal alike in the lake.
Billboard: Wash the boat
The Martins' billboard calls for boaters and fishermen to wash their crafts with hot water between uses. That's a first step, says Kim Bogenschutz, the Iowa Department of Natural Resources' Aquatic Invasive Species Coordinator, based in Boone, Iowa.
And "hot" is a matter of definition.
A water temperature of 104 degrees is enough to effectively kill Zebra Mussels -- and is still relatively safe for people, Bogenschutz says. But a 140-degree water temperature is recommended because of Viral Hemorrhagic Septicemia -- VHS -- a virus that affects multiple fish species -- including walleye, blue gill, muskies, and trout -- and can kill them, she adds.
This means cleaning out a boat at a car wash, with high pressure hot water. "Steaming is incredibly effective."
"A high pressure car wash will probably kill immature, microscopic Zebra Mussels. They're pretty fragile and fall apart, because they need oxygen," Bogenschutz said.
The very minimum treatment when pulling a boat out of a lake is to drain the boat, the bilge, live well and bait bucket and let them dry out for a week before going to another body of water.
And, draining the boat should be done at the boat ramp when leaving the lake, not in to a storm sewer which could put any invasive species into another body of water. "Pull the plug and drain the live well. Be very vigilant. And be sure to remove all vegetation."
This should be done every time a boat is removed from a lake, Bogenschutz cautions, "even if you don't think the lake is infected."
Mike Wahl, the DNR's Regional Fisheries Supervisor, who recently served at Clear Lake for 26 years, explains that the DNR "doesn't want to inconvenience the public. But the effect could be devastating."
Wahl agrees the main focus at this point is educating the boating public. "Cleaning out the lower unit of material that isn't even visible to the naked eye -- getting rid of all moisture that the mussels need to live," is important. And it takes five days of drying to kill the organisms.
DNR staffers, Wahl says, flush their boats with bleach. And once the cooling system is flushed with bleach, it is re-flushed with fresh water and allowed to dry. "Air is caustic," he adds.
Wahl praises the local Water Safety Council for its educational efforts. "Anything we can do to get idea out to the general public is helpful."
Martins see a real threat
Gerald Martin says he and his wife are "worried about what we perceive is a real threat." And, he admits, he hasn't seen a lot of action because it takes a lot of manpower to inspect every boat as it enters local waters.
"I don't think people perceive it to be the threat it is -- a change to the ecology and economy -- and recreational opportunities," in the Iowa Great Lakes area.
Martin says "There's a huge urgency." After the fact -- even discounting the problems with the public water supply, swimmers' feet get cut, he adds. "What can we do then?" he asks. "It's too late."
The Martins spend a week or two of each summer in Okoboji "and long weekends when we can," he says. "We'd like to retire up here. We're tired of drive from Waterloo and could solve it by spending more time here. But I don't want a lake full of Zebra Mussels.
"Then there's no solution -- only a dead body of water. The only solution is keeping them out."
"They (the Zebra Mussels) have already filled Lake Michigan. They've removed the food source. Making the water cleaner results in an algae block. And it makes for foul smelling water."
The ideal solution would be to require wash-outs, limit access to only certain boat ramps and inspect each vessel before it goes into the water, Martin suggests. But that, he admits, would be impractical, due to the manpower required.
More pessimistic?
DNR Fisheries Management Biologist Mike Hawkins is less optimistic. Hawkins serves a nine-county area of Northwest Iowa and notes that "Nature finds a way -- she abhors a vacuum."
Hawkins says he believes "any species will spread if it physically can -- good species as well. But an Aquatic Nuisance Species -- an 'exotic' -- can occupy a niche that is not being used for that location."
The biologist likens the spread of the Zebra Mussel to that of Purple Loosestrife -- a terrestrial plant that is an invader spread by birds.
"Zebra Mussels are not regarded as a nuisance in Europe," Hawkins explains, because they are held in check by other native species. "But when a species like that is put into another environment, the species has the ability to become a nuisance because it leaves behind the diseases that had evolved along with it."
A retired school teacher, DNR Enforcement Officer Bill Maas agrees with Hawkins. "It's not a matter of 'if,' but more likely 'when,'" he says. Not trying to dampen the Martins' enthusiasm, which he applauds, Maas suggests trying to fine a natural enemy to nuisance species.
But, true to his teaching background, Maas warns youngsters that Zebra Mussels will cut their feet when they run on the beach and swim in the lakes.
And, Maas also explains that the DNR does schedule its limited staff and volunteers for the busiest times at the area's boat ramps to educate boaters.
"It take public awareness and a lot of communication," he says.
The DNR's Kevin Baskins explains that in a very narrow sense Zebra Mussels would be a good thing in places like East Lake Okoboji and Spirit Lake, which have seen considerable algae over the years due to runoff of chemicals from the surrounding area.
"The Zebra Mussels will clean the water. You'll be able to see the bottom at 10-foot depths.
"But the bad news is all you'll be able to see is mussels."
Story Comments
Read More and Post Comments 0 comment(s)
Please note: The following are comments from readers. In no way do they represent the views of The Sioux City Journal or Lee Enterprises. We will not edit or alter your comments, but we do reserve the right to not post or to remove comments that violate our code of conduct. No comment may contain potentially libelous statements; obscene, explicit or racist language; personal attacks, insults or threats. Terms of Service
