If you want to get anglers all riled up, bring up the topic of lake and river associations applying chemicals to kill aquatic plants.

That topic created a firestorm on social media this spring when the Indiana DNR announced it issued $585,000 in grant money to lake groups to treat weeds in Hoosier lakes. The 42 projects involve lakes in 16 counties, most of which are in the northern part of the state.

The grants are issued through the Lake and River Enhancement Fund supported by boat owners’ fees paid annually when they register their boats.

The DNR pays for 80 percent of the approved treatments and the sponsoring lake group pays the other 20 percent. The approved projects specify how much and which areas are to be treated, and are designed to only kill “exotic, invasive species plants” that obstruct recreational boating.

To most fishermen, the treatment is always too much and affects the fishing adversely. Most chemicals are applied during the spring spawning season and have been known to eradicate fish habitat completely in treated areas.

According to some lake residents, it’s never enough. As aquatic plants grow during the summer and thicken around shorelines and shallows, many believe it impedes their recreational enjoyment of the lake or river.

Indiana fisheries biologist Jed Pearson is often caught in the middle. He and other fish biologists spend much of their time attending meetings, filling out paperwork and assessing permits to make sure weed treatments are necessary and limited to trouble areas.

“Lake residents say we only care about fishermen, and fishermen say we only care about lake residents,” Pearson says. “We have to factor in all users, but never want to rule at the expense of a fishery.”

Pearson admits it has happened in the past, such as on Lake Webster, where the association was granted a permit to apply the herbicide Sonar several years ago—a lethal chemical that wiped out nearly all of the plant life in the lake. The water turned turbid there and the fishing suffered. Plant life has since come back and the fishing is now improving.

Pearson said future weed treatments involving extreme chemicals like Sonar will be scrutinized closely before approved, and used only in specific situations.

“We were told that some of these chemicals are selective in what they kill, but we’re finding out in the real world, not so much.”

Pearson added that excessive weed treatments harm water quality, plant life and production of insects. That not only affects the fishing, but the water clarity as well.

“We try to stress to lake property owners that aquatic plants tie up nutrients and supply oxygen to the water. They help reduce algae blooms and provide better fish habitat. When you have fewer plants, it can lead to changes in fish survival, growth and behavior, not to mention change the appearance of the water clarity.”

But he also said that areas of lakes heavily choked with vegetation interfere with the ability of bass to prey on small bluegills. When that happens, too many bluegills survive and there isn’t enough food to support them. In other words, there has to be a balance, which is why Indiana has employed stricter regulations the past few years on weed treatments.

However, Michigan has less restrictive regulations and the fisheries department there has little or no say in the permit-approval process. Presently, the DNR’s Department of Environmental Quality (DEQ) handles all weed-treatment permits.

That could be changing, though, says Brian Gunderman, a southwest Michigan DNR fisheries biologist.

“We get a lot of complaints from anglers that these treatments are reshaping fish habitat,” Gunderman said. “In some cases, there is collateral damage when plants are treated. It’s definitely a heated issue that we’re looking at.”

Oftentimes, Michigan fishermen report fish die-offs or kills that they believe are directly related to recent chemical applications.

Gunderman says efforts are underway to include the fisheries division’s perspective in how weed treatments are permitted. A workgroup consisting of fisheries and DEQ has been established to look into these matters.

“The DEQ permit process is geared more toward providing human safety (as far as chemicals that are being applied) than toward habitat,” he said. “There are restrictions on spraying around spawning beds, but we never see the permits that are issued.”

Eurasian milfoil is one of the prime targets of chemical applications in both states. Milfoil was introduced to Michiana lakes some 50 years ago and attempts to eradicate it have failed. While chemical treatments knock milfoil down, the plants keep coming back.

Initially, DNR officials believe that eliminating milfoil would allow native plants to regrow. However, many native plants are being lost to other water-quality issues.

Milfoil becomes the fishes’ only option, and when kept in check, it can improve water clarity.

“Milfoil is better than no plants at all,” Gunderman said.

For this reason, biologists are beginning to accept that milfoil does provide good fish habitat where native plants aren’t available.

“Where milfoil has a foothold, there isn’t a treatment that eliminates it, so now the focus is to reduce it in areas where it impairs navigation,” Pearson said.

The challenge for biologists will be to keep lake residents happy while sustaining good fish habitat to satisfy the anglers.