Fishing on Mille Lacs since the season opened May 12 has been good, with hook-and-line anglers regularly catching walleyes, including some big ones in the mid-20-inch range.

But it’s nets that are getting much of the attention on Mille Lacs, particularly one that was either lost or abandoned this spring by Fond du Lac band members. The net, which by one account had 67 dead walleyes in it, weighing 112.4 pounds, was reported to Department of Natural Resources conservation officers by a local resident and removed from the lake May 20.

An investigation is underway into who was responsible for the net, Fond du Lac band chief conservation officer John Smith said Tuesday.

“It’s under investigation, that’s all I can say,’’ Smith said.

Beyond acknowledging the net was found, Minnesota DNR regional fisheries manager Brad Parsons also declined to elaborate.

The dead walleyes will be counted against the Fond du Lac band’s share of walleyes that it and seven other Chippewa bands net and spear from Mille Lacs this year. Because of the late ice-out, the tribal harvest is behind, and is ongoing, Parsons said.

For only the second time since the Chippewa and the state began comanaging Mille Lacs fisheries in the 1990s, the two couldn’t agree this year on a “safe harvest level’’ of Mille Lacs walleyes — meaning the poundage the parties believe can be safely removed from the lake without hurting the fishery.

The DNR believes 150,000 pounds of walleyes can come out of Mille Lacs this year, while the bands’ number is 120,000. So far, neither side has sought mediation to resolve the disparity, as is allowed under the court agreement charging the two with Mille Lacs oversight.

Only the bands are allowed to take fish from the lake this year, up to a self-imposed harvest quota of 47,200 pounds. Anglers aren’t allowed to keep any Mille Lacs walleyes. So the state’s 76,450-pound walleye quota (deducting for repayments of past-years’ overages and this past winter’s harvest) will occur as an estimate of walleyes that are caught and subsequently die upon release — a phenomenon called “hooking mortality.’’

Meanwhile, the DNR said Tuesday that through June its fisheries staff will set nets in Mille Lacs in an attempt to count the number of walleyes the big lake holds. The nets will try to recapture some of the 20,000 Mille Lacs walleyes that were captured and tagged this spring, thus providing a population gauge.

Anglers catching tagged Mille Lacs walleyes are asked to report the tags’ numbers and location of catches online at mndnr.gov/tagged-fish.