It all started by accident in 1988 when a fish stocking crew delivered a batch of rainbow trout to Yawkey Mine Lake, a 14-acre canyon of cold water near Cuyuna Country State Recreation Area outside of Crosby, Minn.
Mistakenly included in the load were a number of baby lake trout. No one knows how many. Years later, when those "lakers" started showing up on local fish stringers, word got around. Accordingly, when the Department of Natural Resources surveyed Yawkey's anglers during the winter of 2016, fisheries managers learned that 39% of the lake's ice fishing effort was aimed at catching lake trout. One year earlier, the DNR had lifted a winter trout fishing ban on area mine lakes.
The Yawkey creel survey estimated the total catch of lake trout at 77 for the winter, with 26 harvested and 51 released. The keepers ranged in size from 11 to 18 inches, proof that Yawkey's surprise game fish population had been reproducing on its own.
"The creel showed us there was a real desire to have more lake trout fishing," said Marc Bacigalupi, DNR fisheries supervisor for the Brainerd area.
The agency has responded by introducing lake trout to a few other mine lakes in the area while also amending fishing regulations to protect spawners and foster natural reproduction. Those changes — a bag limit of one laker over 20 inches with a bait restriction of no live minnows — could be adopted as early as next month before winter lake trout season ends March 31.
"It'll protect the fish until they are mature and of spawning age and people will have a quality-sized fish to keep," Bacigalupi said. "We've heard reports of some big ones" caught in Yawkey.
The DNR has long maintained a popular rainbow trout stocking program in certain lakes around Brainerd and Crosby-Ironton, but those yearly hatchery-supported efforts are considered "put and take" with no natural reproduction.
Bacigalupi said the cold, deep waters of certain mine lakes — if they also provide a decent forage base — are capable of growing sustainable lake trout populations on the species' southernmost habitat range in Minnesota. The plan is to stock them every other year with yearling lake trout, adding small bunches of mature brood stock lake trout retired from the Peterson State Fish Hatchery.