Mille Lacs Lake fall fish survey shows promise

For the first time since 2008, Mille Lacs Lake walleye surviving into their second year remain abundant and the following year’s hatch appears to be doing well, according to the Minnesota Department of Natural Resources.

“We’re far from out of the woods on Mille Lacs Lake,” said Rick Bruesewitz, Aitkin area fisheries supervisor for the DNR. “But younger walleye are showing more positive signs of survival than they have in past years.”

That’s good news for the lake’s walleye population, which has been declining because the vast majority of walleye that hatch in Mille Lacs have not grown into yearlings by surviving to their second autumn. When not enough smaller fish grow into larger ones, the population eventually drops.

As expected, the walleye catch in all types of nets during this fall’s population assessment was down slightly from last year but there were strong numbers of walleye hatched the previous year in all surveys. Catch rates of these walleye were among the highest observed since 1991 for electrofishing and 2006 for fine-mesh gill nets.

“This year class survived its first year much better than any of the year classes from the previous four years,” Bruesewitz said. “They look pretty strong going into 2015.”

Electrofishing for walleye hatched this year produced average numbers when compared with catches from previous years, indicating that reproduction in 2014 was again successful. Walleye hatched this year were a little below average in size. This may be related to a lack of food caused by low numbers of newly hatched perch, which serve as the primary food source for newly hatched walleye.

High numbers of newly hatched and yearling tullibee, which range from 3-8 inches long, were too large for newly hatched walleye to eat but their availability will provide more food for larger walleye.

“Both of these tullibee age classes were caught at the highest levels we’ve seen in the forage nets,” Bruesewitz said. “With that much food for larger predators, smaller walleye may have had a better chance of survival from predation. This food resource also appears to have improved the overall condition of larger walleye, which was better than we’ve seen for several years.”

More perch ranging from 6- to 7.9-inches were caught in near-shore and offshore nets but the number of perch longer than 9 inches remained at about the same relatively low level.

Results of assessment netting also showed high numbers of northern pike, many of which range from 22- to 28-inches although fish as long as 39.7 inches were observed in the survey. Smallmouth bass numbers decreased slightly close to shore but increased in off-shore nets. Tullibee numbers increased throughout the lake.

DNR staff continue to compile catch information from fall assessment surveys, including age analysis. Once complete, the data will be added into the stock assessment modeling carried out by both state and tribal biologists.

Annual Mille Lacs Lake safe harvest levels are based on fish population assessments in combination with other sources of information, including past harvest statistics. The DNR and eight Indian bands will evaluate technical data and modeling results related to Mille Lacs Lake and use that information to reach agreement on final safe harvest levels in January. The DNR uses these levels as the basis for walleye management.

Mille Lacs Lake covers 132,000 acres. State anglers are expected to harvest close to 30,000 pounds of walleye this fishing season from an allocation of 42,900 pounds. Indian bands with rights under the 1837 Treaty harvested about 13,000 pounds of walleye last spring. Their total allocation was 17,100 pounds.

For more information on Mille Lacs Lake, visit www.mndnr.gov/millelacslake.