The reclamation project to kill and replace all the fish in Pickerel and Mud lakes could begin next week.

The intent of the reclamation project is to improve water quality on Pickerel Lake. A large rough fish population, mostly carp, has damaged habitat in the lake. Carp also contribute to algae blooms by stirring up sediments at the bottom of the lake.

“In the absence of carp, the lake should — in the long run — sustain much better water clarity and support a lot more fish and wildlife habitat with the lake system,” said Jeanine Vorland, DNR area wildlife manager.

The rotenone could be applied Oct 5 and 6, depending on the weather. The rotenone will be applied to the lake from a helicopter. Vorland said it’s very similar to crop dusting from a helicopter. Rain or high winds will force the DNR to delay the process.

The DNR will have groups that will apply the chemical to ditches and other areas that are too small for the plane. Drip stations will be used in areas with running water, and Vorland said those systems drive fish to open water.

Vorland said the recent low rainfall totals have benefited the project, because it will help keep the rotenone from flowing to other bodies of water. To keep the chemical from spreading more than intended, the DNR will be putting sandbags in some areas.

If necessary, a chemical can be used to prevent rotenone in other bodies of water.

Rotenone is a chemical that affects gill-breathing animals and can also be used as an insecticide.

“It’s just like treating the agricultural fields. You go fairly quickly with the aircraft, but we do need the good conditions. Once it’s all over and the chemical mixes with water, then it’s safe for reentry,” Vorland said.

This project will also affect other area lakes.

“Fountain Lake and Albert Lea Lake kind of suffer from the amount of nutrient and algae that’s coming down the system from the head water areas,” Vorland said.

An electric fish barrier near the outlet of Mud Lake in the Magaksica Wildlife Management Area will keep rough fish from re-entering the lake, but Vorland said the barrier also keeps the fish in the lake.

Natural fish kills during the winter are common, especially on shallow bodies of water like Pickerel Lake. However, Vorland said it’s too unreliable to wait for such a kill, which could take a number of years.

The rotenone will also be applied to many of the tributaries and ditches that lead to the lake to ensure that there isn’t another source for rough fish to re-populate the lake.

Once the rotenone comes in contact with the water, it begins breaking down because of contact to sunlight and organic sediment at the bottom of the lake. Vorland said traces of the chemical should be gone within a few weeks of application.

After the rotenone application, the DNR is not planning to remove the fish. Vorland said leaving the fish should be similar to a winter fish kill, where the fish sink and naturally decay at the bottom rather than floating. The DNR could remove some fish if there’s a high number floating near a home or public area.

The lake will be closed to public access during the rotenone application. For a few days after the application, the water will likely have a chemical odor that Vorland compared to mothballs.

Since the rotenone affects animals’ ability to breath through their gills, it should have little affect on mammals. However, Vorland said the chemical can affect invertebrate species, some turtles and some amphibians.

The DNR will restock the lake in the spring, likely with northern pike, perch and blue gills. It will take a few years before the fish grow to catchable size.

“In the short run, it’s a pretty devastating thing to do to a fishery. But in the long run we think we’ll have better fishing and a better fish community out there,” Vorland said.

While the water quality can take a few years after a project like this before it improves, Vorland said improved water quality is a key goal in this process. If the treatment is effective, that should improve the quality for a number of years. However, Vorland said that doesn’t account for all sources of pollution in the lake. She said the DNR will need to work with local officials to prevent other causes, too.