Indiana Lake Overflowing with Small Bluegills
Small, slow-growing bluegills continue to over-populate Upper Long Lake in southwest Noble County despite the stocking of additional predator fish to reduce their number.
Since 1996, the local lake association and the Lake Webster Musky Club have released more than 3,000 muskies in the 86-acre natural lake.
The fish were purchased from a private hatchery in Wisconsin and stocked with permission of the DNR's Division of Fish and Wildlife.
Muskies are large, toothy predator fish that can grow more than 4 feet long. They are similar to northern pike, but unlike pike, they are not native to Indiana natural lakes.
Part of the reason for stocking muskies in Upper Long Lake, was that local residents, anglers and the DNR hoped they would prey on small bluegills. The reasoning was that once bluegill numbers declined, those that survived would have more food per fish and could grow larger.
That was a good idea in theory but not so in reality.
Based on recent sampling by DNR biologists, bluegills are now more abundant than ever before. And they are smaller.
"I've never seen so many small bluegills in a lake," said Matt Horsley, a DFW fisheries intern and recent graduate of Michigan State University.
Horsley was part of a three-person crew that captured 700 bluegills in only 30 minutes of electro-fishing along the shoreline. At times, so many bluegills were stunned by the shocker boat that Horsley couldn't net them all fast enough.
Of the 700 bluegills, 97 percent were less than 6 inches long. Only eight were larger than 6 inches and only three were larger than 7 inches.
The electro-fishing catch rate of 3- to 5-inch bluegills was 340 per 15 minutes of sampling, the highest ever recorded at an Indiana natural lake during a June survey and second only to a catch rate of 460 per 15 minutes at nearby Loon Lake in July 2004.
Ironically, muskies stocked in Loon Lake, as well as in Skinner Lake, east of Albion, have also failed to reduce bluegill numbers and increase bluegill size. Biologists speculate that muskies likely prefer to eat other species, including other predator fish, which may actually reduce predation on bluegills.
According to Horsley, the overall catch rate of bluegills at Upper Long Lake averaged 282 per 15 minutes from 1991 through 2010. A typical catch rate at other Indiana natural lakes is 100.
"We don't know why bluegills are so abundant in Upper Long Lake. That's something we are still trying to figure out," Horsley said.
Meanwhile, anglers may want to switch to muskie fishing there. Horsley also caught 10 muskies during the survey.