SYRACUSE – Wearing bright blue protective gloves, Dave Bowser navigated a boat on Lake Wawasee as he sprayed herbicide onto a plant familiar to aquarium owners.
The exotic plant, called Eurasian water milfoil, may be attractive when used to decorate aquariums full of tropical fish, but it becomes a serious threat when introduced into wild lakes.
After it’s in the wild, the exotic plant grows into thick tangles of long stems and feather-like leaves that reach the lake’s surface, creating patches that can stop a fast-moving sailboat, grab lines cast by fishermen and make swimmers cringe as they feel the plant brush against them.
If it’s left unchecked, fish could also be endangered.
Despite Lake Wawasee’s gravel and sand bottom, the hardy invader has managed to cover at least 100 acres of the 3,200-acre lake, and it would likely spread if it weren’t for routine herbicide treatments like the one done by Bowser, an employee of Aquatic Weed Control, a Syracuse-based company.
Exotic invasive plants like the one in Lake Wawasee are easily spread from lake to lake by boats and through flowing currents, threatening to choke not only the lakes, rivers and wetlands that dot so much of northeast Indiana but also other waters throughout the U.S. and the world.
In Indiana, one man leads the battle against these exotic invaders – Doug Keller, the aquatic invasive species coordinator for the Department of Natural Resources.
Keller said the invasive plants likely already affect most Indiana lakes and, while the battle against them is costly, further infestation could result in unusable lakes and plummeting land values.
That was the concern at Meserve Lake in Steuben County when the local association saw a strange new plant begin to quickly spread in areas of the lake.
It was so thick, you could almost walk on it, said Paul Clark, president of The Life of Riley Mobile Home Estates Association.
An aquatic plant is considered invasive if it isn’t native to Indiana and if it threatens recreation or the environment, Keller said.
While the plants may feed hungry fish in the areas where they grow naturally, if they are transplanted into another environment without such curbs on their growth, they can easily choke out native aquatic plants.
The invaders’ dense growth can lead to a dangerous drop in oxygen levels at night, when plants absorb oxygen from the water, which Keller said could lead to a fish kill.
The dense growth can provide shelter for smaller fish, forcing predator fish like bass to use more energy when seeking food, Keller said. Then, overpopulation by smaller fish and stunted predator fish is possible.
Two water invaders in Indiana – Eurasian water milfoil and curly leaf pondweed – may have been introduced to the wild when aquariums were dumped into water, Keller said.
Keller said plants can also be either accidentally or purposely introduced from a newer popular backyard feature – water gardens.
Both Brazilian elodea and parrotfeather are used in water gardens, and Keller believes Indiana has seen only the tip of the iceberg when it comes to non-native aquatic plants that have escaped from backyards.
That’s kind of an issue we’re facing right now, Keller said.
After being contacted by area residents in 2008, officials learned parrotfeather was growing in Meserve Lake, a roughly 16-acre lake near Angola. The plant’s presence was reported to officials after it quickly grew to cover about a third of the lake.
Clark, who has lived near the lake for 21 years, said another association member pointed out the strange new plant to him.
It was just all over, Clark said. You wouldn’t have any problems seeing it.
Parrotfeather can easily affect boating, fishing and swimming, since it can grow in water as deep as 15 feet until it eventually extends about a foot above the surface, Keller said.
In one year, Clark said a patch of parrotfeather growing off the association’s beach grew from about 10 feet in diameter to about 40 feet in diameter.
Though Meserve Lake is small, it is located at the head of the Pigeon Creek chain, which flows into a number of lakes, said Keller, who added that it could spread through the water current.
Eradication of invaders can be difficult since they often spread through fragmentation, which means that a chopped-off portion of the plant can float away and become established in a new area.
Plant fragments may also attach to boats and, when the boat is moved, the plant can become established in a new body of water.
A costly problem
Although herbicides are used in attempts to control the growth of aquatic invasive plants, treatment can be costly.
Treatment began at Meserve Lake in 2008, and Keller said about $35,000 will be spent at the lake this year. Further treatment may be needed next year.
Keller estimated $1.5 million will be spent to treat another invasive plant, hydrilla, at Lake Manitou in Fulton County. That money has come from state grants as well as through a national fund paid for by fishing licenses, Keller said.
Donahoe said it cost about $350 an acre to treat the patch of Eurasian water milfoil at Lake Wawasee this week.
The money to treat lakes comes from a combination of state grants funded by boat registration fees and payments made by lake associations – at least those associations that can afford to help.
Clark said The Life of Riley Mobile Home Estates Association currently has about 18 members who have paid their $15 annual dues. When the association’s leaders were told it would cost $40,000 to treat the lake, Clark said they knew the association’s coffers couldn’t afford to pay much of the cost.
Annually, about $700,000 of Lake and River Enhancement grants – which are funded by boat registration fees – are dedicated to treating curly leaf pondweed and Eurasion water milfoil, Keller said, adding that the amount falls short of what could be spent to treat the plants.
But not treating the invaders isn’t an option, because Keller said the lakes could be ruined.
So, absolutely, property values go down. That’s a whole lot of justification we use to keep these things out of there.
At Meserve Lake, Clark said, the parrotfeather seemed to die quickly after one treatment last summer, but it came back within a month.
The lake has received another treatment this year and, so far, Clark said the plant hasn’t reappeared, though he won’t know for a few weeks whether it will reappear and require further treatment.
Hopefully we never do again, because really it’s costing the state a bunch of money.