By Louie Stout

Two nice Lake Manitou yellow perch

Lake Manitou in Rochester, Ind. - once one of northern Indiana’s best bass lakes - continues to show recovery from the massive chemical treatments it received over a 10-year period.

The treatments, which began in 2006, were required after an infestation of hydrilla, a fast-spreading invasive plant, was discovered in the lake.

Manitou was the only lake in Indiana that contained the plant, so the boat ramps were closed and fish managers applied heavy doses of chemicals to eliminate the plant at its roots.

Although the chemicals used were designed to specifically eradicate the hydrilla, other plants throughout the lake were knocked back.

District fish biologist Tom Bacula said the recovery is slow, but he was encouraged when he saw multiple year bass classes while surveying the lake early last May and again in June.

The water temperature was 60 degrees in May and most of the bass turned up during four hours of electro-fishing were in the channels.

“When we were there in 2017, we only found a couple of year classes,” he said. “This year, we saw more, and when we went back in June to look at other species, we saw large clouds of young bass and a ton of little bass.”

His biggest concern is the large shad population that competes with the young bass for the tiny organisms they need to eat before they can begin feeding on minnows and crawfish.

“The shad spawn before the bass, so there are lot of non-game fish gobbling up the plankton that newly hatched bass need,” he said. “The bluegill and perch feed on bugs and plankton and the bluegill spawn later when there is more plankton available.”

Bacula said the adult bass were growing at a typical rate compared to other northern lakes. The fish reach the legal length of 14 inches between 4 and 5 years.

Oddly enough, Bacula said the bluegill, white bass and yellow perch and channel catfish seem to be doing quite well.

“Perch were doing surprisingly well,” he said. “We saw sizes up to 13 inches. The bluegills appear to be doing better than they were the last time we were there. We captured bluegills up to 9.2 inches.”

The plant community has rebounded quite well and should help the bass population in the future.

“It’s going to take time to get the bass population back where it was, but I was encouraged by some of the things I saw.”