Ask any angler who has fished Island Lake Reservoir near Duluth in recent decades and they will tell you the lake has lots of walleyes. Very small walleyes.
The vast majority of fish caught are in the 10- to 13-inch range, smaller than what most anglers would consider a keeper. Fish population surveys found the same thing, with average sizes around 12 inches long, down from a 17-inch average in the 1960s.
Last fall in a public meeting, Department of Natural Resources fisheries experts asked anglers if they wanted to try something new to get bigger walleyes in Island Lake, a big, man-made reservoir created in the early 1900s. The answer was a resounding “Yes!” Now the DNR plan is ready for a formal public airing, with a public meeting set for October.
The draft DNR proposal includes a slot limit requiring anglers to release all walleyes between 15 and 20 inches. Anglers could keep one walleye over 20 inches long, pretty much a standard statewide. But here’s the idea totally new to Minnesota walleye management: The DNR wants to let anglers keep up to 10 walleyes per day under 15 inches with no minimum size limit. That's an extra four fish per day more than currently allowed and four more than anywhere else in the state.
Dan Wilfond, Duluth-area large lakes specialist for the DNR, said the 10,800-acre lake has more walleyes than it can biologically support, especially a surplus of small fish. The infertile lake has limited food for fish. And that makes walleyes in the lake grow slower than any other lake in the region, Wilfond said. Catch rates are very high, but the majority of walleyes never get very big.
In a sense, the walleyes in Island Lake are stunted, a phrase often used with bluegill or northern pike populations but almost never with walleyes.
“This would be completely new to Minnesota walleye management, or walleye management anywhere from what I can tell,’’ Wilfond said. “But this is an unusual circumstance in that lake and we thought we needed to try something different.”
In addition to lack of food, Wilfond said Island Lake walleyes may be impacted by spiny water fleas. In 1990 Island Lake was the first inland lake in Minnesota confirmed with the invasive species (a Eurasian native that likely arrived in the Twin Ports in the ballast of ships) and it appears walleye growth has slowed even more since they arrived (oddly, perch growth seems to have increased.)
Spiny water fleas are one reason Wilfond has proposed introducing coldwater cisco into the lake. Studies show cisco could thrive, especially in the coolwater deep zones of the reservoir. Cisco eat spiny water fleas. And cisco also would provide very hardy, high-calorie meals for walleyes and likely spur walleye growth rates.
For now Wilfond said the cisco introduction faces some hurdles. Introducing new species to lakes on purpose is rare in Minnesota in recent decades. And because Island Lake is linked to Lake Superior via the Cloquet and St. Louis rivers, DNR officials will want to make sure any introduced fish are not just disease-free but also won’t interfere genetically with native Lake Superior fish.
“That part is harder for sure. There are some obstacles with cisco. ... But it’s not dead yet,’’ Wilfond said of the cisco plan.
If there’s support from the public, and DNR leaders in St. Paul, the new rules would take effect in March, 2021.
The DNR will put the Island Lake walleye plan before the angling public at a meeting set for Oct. 8 in the Rice Lake City Hall, 4107 W. Beyer Rd., from 6:30-8:30 p.m.
You can see more of the plan at files.dnr.state.mn.us/areas/fisheries/duluth/island_lake-update.pdf and you can comment by email to email@example.com.