One Southeast Wisconsin Lake's Long Journey Toward a Healthy Ecosystem
Inland fishing season opens Saturday.
Thirty years ago, Eagle Lake would not have been a popular angler destination. The rural Racine County lake was dominated by common carp. The fish is not native to North American waters, but has been around a long time.
They were one of various game species that were brought over with the settlers. "Actually if you go to Europe, they’re a prize game fish, known for their fighting ability and people love to fish for them,” says Luke Roffler, senior fisheries biologist with the Wisconsin DNR.
Eagle Lake is one of 69 lakes Roffler monitors in southeastern Wisconsin.
He says Wisconsin fish biologists and most anglers do not share the European love of carp. They reproduce prolifically and are bottom feeders.
Roffler says when their numbers explode, carp turn a lake’s ecosystem upside down. “It’s kind of vicious cycle, to a point your native game fish can’t see their forage, plant beds are decreasing so you’ve got less habitat for your pan fish and pretty soon you’ve got a nutrient-rich carp pond,” he says.
Eagle Lake has another aquatic stressor. It is part of a watershed that supports a lot of agriculture.
“A lot of runoff from the various farm fields and whatnot. Sometimes it gets to the point of nuisance in terms of plant growth and water quality especially later into the summer,” Roffler says.
Nutrients like nitrogen and phosphorus are great for growing crops, but trigger algal growth in rivers and lakes.
Roffler says three decades ago, Eagle Lake’s carp count reached crisis proportions. So the DNR equipped a helicopter with a powerful chemical. “Within a 30 year time span, there were three rotenone chemical treatments,” he says.
Roffler calls rotenone last-ditch effort. It isn’t selective – it kills any species in its path. “Then you have to wait several years for everything to get back on its feet,” he says.
Eagle Lake got its last rotenone dose eight years ago.
Meanwhile, teams stocked native fish species to rebuild their numbers – from the smallest fathead minnow to predators including northern pike. “We are still putting pike into the system, even though they’re numbers are very good in here.” Roffler says.
He has not seen another carp in the system since the most recent treatment; and hopes a natural balance is being struck.
“The fish community is often just an expression of all of the other conditions within the system, some of which are in our control and some are out of our control,” Roffler says.
John Craddock Sr. is here alone today, but often fishes next to the public boat launch with a few of his fourteen grandchildren tagging along.
“A lot of them wanted to skip school today when they found out I was going fishing, but they had to go to school,” he says.
As part of Eagle Lake’s restoration strategy, anglers are allowed fewer fish and they have to be bigger.
“You want to be able to keep what you catch. And you can’t get enough to put in a skillet. I caught a few bluegills this morning. They have to be eight inches [to keep.] They weren’t that big, so I had to put them back,” Craddock says.
Nearby, Greg Krueger casts a plastic wiggler – warming up, he says, for opening day.
“I walked seven miles to get here. Yeah I’m legally blind, so I can’t do a whole lot. So I can fish and walk,” Krueger says.
He started fishing years ago. Krueger says he came from a big family and their dad often took all of them fishing.
Krueger shares his family’s philosophy. “My wife caught one of the biggest bass I ever saw out here, but she never keeps her fish. She threw it back. She calls it fish karma, she wants to keep the good karma going,” he says.
As for DNR fish biologist Luke Roffler, he wants to keep the Greg Kruegers and John Craddocks of the world satisfied.