Big change for a little lake

Watershed tour highlights projects on Shields Lake

Once upon a time, a handsome prince ruled over the Kingdom of Bohemia. Within his family’s estates, Prince Schwarzenberg had elegant palaces, imposing castles, and 20,000 acres of carp ponds. The hardy fish were a symbol of opulent wealth and provided a steady source of delicious, nourishing food – a treat that many peasants in the country could only hope to enjoy on holidays and special occasions. Today, carp is still a favorite meal for Christmas dinner in central Europe. In fact, many families will buy their fish live two to three days in advance and let them swim in their bathtubs at home to freshen before the holiday feast.

A woman in Prague buys carp for a holiday dinner. Photo by Andrew Stawarz.

Here in the United States, we have much less love than the Europeans for these non-native fish, which uproot aquatic plants, stir up sediment in lakes, and reproduce abundantly. During a Comfort Lake – Forest Lake watershed tour on Saturday, Sept. 21, local leaders learned about several projects to improve water quality in area lakes, including a carp harvest occurring on Shields Lake later that day.

Carp once swam exclusively within the Black Sea, Caspian Sea, Aral Sea and Danube River, but are now found in virtually every part of the world. European immigrants brought carp along with them as they spread out across the continents because the fish grow fast and can tolerate almost any conditions – muddy water, low-oxygen, and even heavy pollution. In the U.S., entrepreneurs brought carp as a familiar food staple, not realizing the problems they’d one day cause for our rivers and lakes.

“Shields was treated once in the late 1990s,” explained Curt Sparks, a member of the watershed district’s citizen advisory committee. “Back then, we drained the lake and treated it with rotenone to kill the carp. Afterwards, the walleye and game fish were great for several years until the carp eventually migrated back in.” This time around, contractors used a gill net to collect as many carp as possible without harming native fish. The watershed district is also working to address underlying problems so that Shields Lake doesn’t regress once the water gets clean.

CLFLWD carp harvest in Bone Lake 2010
Carp harvest in nearby Bone Lake 2010.

Comfort Lake – Forest Lake Watershed District is completing a stormwater harvest and reuse project at Forest Hills Golf club that will keep up to 94 pounds per year of phosphorus out of Shields Lake and is also conducting an alum treatment to pull existing phosphorus out of the water and trap it at the bottom of the lake. Together, these efforts will help to restore clear water in Shields Lake and keep 250 pounds per year of phosphorus out of Forest Lake. Similar work in Chisago’s Moody Lake has improved water quality and created better habitat for native fish.

Meanwhile, local royalty hoping to enjoy a meal of carp this fall will have to look elsewhere for their dinners. In addition to removing carp from area lakes, the Comfort Lake – Forest Lake Watershed District has also installed fish barriers in several locations to prevent the carp from coming back.

Once upon a time, a handsome prince raised carp for his holiday dinner. Here in Forest Lake, however, the menu calls for walleye.