Late last fall, long af­ter most Min­ne­so­tans had stored their boats for the win­ter, Paul Hart­man still was casting over­sized baits into chilly Lake Mil­le Lacs, hop­ing against hope for a kill­er strike — and a big muskie.

Day af­ter day he tossed and re­trieved crank­baits, jerkbaits and bucktails, be­fore, fi­nal­ly, on Nov. 12, boat­ing a 56-inch-long mon­ster.

Hart­man makes no at­tempt to ra­tion­al­ly justi­fy the time he spent hunt­ing for his tooth­y tro­phy.

“Yes, it was a huge muskie,’’ Hart­man said. “On the oth­er hand, it took me more than two years of my life fish­ing on Mil­le Lacs to catch it.’’

Hart­man owns and pro­motes George’s Min­ne­so­ta Muskie Expo, which runs Fri­day through Sun­day at Con­cordia University in St. Paul. Now in its 21st year, the show is named for its late found­er, George Wahl.

At the expo, which is fair­ly de­scribed as an orgy of muskie lures and oth­er e­quip­ment, along with near­ly con­tin­u­ous how-to semi­nars, Hart­man will be joined by thou­sands of an­glers who share his muskie ob­ses­sion.

And for good rea­son: While wall­eyes re­main Min­ne­so­ta’s most prized fish, and pan­fish such as sunnies and crap­pies its most popu­lar, muskies, ar­gu­a­bly, are its most spec­tac­u­lar — wheth­er meas­ured by size, col­or­ing, an­gry demeanor or mem­ories pro­vid­ed to the luck­y an­glers who catch them.

Yet trou­ble seems a­foot with the state’s muskies, and it’s not re­lated to the brick­bats some lakeshore own­ers hurl at the Department of Nat­u­ral Resources when the a­gen­cy pro­pos­es to intro­duce these al­pha preda­tors into one of “their’’ lakes.

Just the op­pos­ite.

“For a while, say be­tween 2005 and 2010, muskie fish­ing was spec­tac­u­lar in what we call the state’s ‘leg­acy’ lakes, such as Mil­le Lacs, Ver­mi­lion, Cass and oth­ers,’’ Hart­man, of the Twin Cities, said. “Now, with suc­cess fall­ing off, some peo­ple have gotten out of muskie fish­ing, while oth­ers are look­ing for new lures or ‘the next big thing’ to try to catch these fish.’’

Luke Ronnestrand agrees. He guides muskie an­glers 70 days or more each year on Lake Ver­mi­lion in north­ern Min­ne­so­ta.

“Com­pared to the past, Ver­mi­lion guides are hav­ing to burn a lot more gas and stay on the wa­ter long­er to pro­duce fish for cli­ents,’’ Ronnestrand said. “As a re­sult, we’ve seen the num­ber of an­glers com­ing to the lake de­cline since a­bout 2009.’’

Multi­ple for­ces are at play, said Neil Vanderbosch, a DNR fish­er­ies man­ag­er. One is that when muskies were intro­duced into some of these waters — Mil­le Lacs was first stocked with muskie finger­lings in 1984 — their num­bers in­i­tial­ly flour­ished, yield­ing fish of vari­ous sizes, in­clud­ing, in time, some long­er than 45 inch­es.

Now, 15 years or so later, small­er muskies seem to be miss­ing from Mil­le Lacs (and cer­tain oth­er waters) al­to­geth­er, while the lake’s re­main­ing muskies are far fewer — and gargantuan.

Case in point: In late 2015, a muskie es­ti­mat­ed to weigh 61 pounds was caught on Mil­le Lacs by Dom­i­nic Hoyos of Stillwater, top­ping a 57-inch be­he­moth land­ed only 16 days earli­er by Robert Haw­kins, own­er of Bob Mit­chell’s Fly Shop in St. Paul.

DNR fish­er­ies chief Don Pe­rei­ra agrees that some Min­ne­so­ta lakes “aren’t per­form­ing for muskies the way they have his­tor­i­cal­ly.’’

The DNR’s a­bil­i­ty to pro­duce muskie finger­lings for stock­ing is lim­it­ed by budg­et and fa­cil­i­ty con­straints, Pe­rei­ra said. Still, fish­er­ies man­ag­ers in­tend to re­fine their stock­ing meth­od­olo­gies, he said, while also tag­ging plant­ed finger­lings to bet­ter de­ter­mine stock­ing suc­cess.

Asked wheth­er the DNR’s plan to stock muskies in three more state lakes or rivers by 2020 should be re-ev­alu­at­ed, with more em­pha­sis placed on man­ag­ing the state’s cur­rent muskie waters, Pe­rei­ra said, not yet.

Vanderbosch of the DNR es­ti­mat­ed that 10-15 years might pass be­fore it’s known what’s going on with muskies in state lakes.

That’s too long, said muskie guide Josh Ste­ven­son, own­er of Blue Rib­bon Bait & Tack­le in Oak­dale and White Bear Lake.

“Not many years ago, I boat­ed more than 100 muskies a year. Now a lot of work goes into crack­ing 60 or 70,’’ Ste­ven­son said. “Min­ne­so­ta may be the ‘State of Wall­eyes. But now it’s also the ‘State of Muskies,’ and I would think the state would want to pay close at­ten­tion to how these lakes are stocked and man­aged so this great fish­er­y can be sus­tained.’’

Den­nis Anderson dennisanderson@startribune.com