New Minnesota DNR fisheries chief Don Pereira tries to answer the unanswerable: What’s wrong with Mille Lacs walleyes?
New Minnesota DNR fisheries chief Don Pereira tries to answer the unanswerable: What's wrong with Mille Lacs walleyes?
Q: What’s the status of Mille Lacs walleyes?
A: We have an abundance of spawning females. But there’s an elevated mortality of young walleyes, and we’re not sure why. Walleyes are in the lake in good numbers after the spawn, but they’re not surviving in sufficient numbers as yearlings and 2-year-olds. We haven’t had a notable year class since 2008, and good year classes before then were too infrequent.
A: Our leading hypothesis is that they are probably dying from elevated predation. Mille Lacs became clearer and clearer beginning in the late 1990s. At the same time, we detected that walleyes were moving offshore at a much smaller size than they historically have. We think that the clearer water, and the predation that it might have encouraged, might have been the reason. Meanwhile, we know that smallmouth bass in the lake have increased dramatically, as have larger walleyes and northern pike, all of which prey at times on small walleyes. That said, we’re unsure exactly how these things work together.
Q: When might you figure it out?
A: We had a good predator diet study this year. But fish feed differently, year by year. We’ll get an initial look at which predators are consuming young walleye this year, but will certainly firm up this work with additional years of predator diet sampling.
Q: Have Mille Lacs regulations protected too many big walleyes, which in turn feed on small walleyes?
A: It’s possible. But I want to stress that Mille Lacs appears to be unique in that regard. We’ve had similar protective slots on Rainy Lake for 20 years and on Winnie for 10 years. We’re still seeing good reproduction on those lakes, without loss of year classes as the fish mature. But regarding Mille Lacs, the mistake we might have made was focusing fishing mortality on walleyes 15-18 inches long. We now know a sustainable fishery should be exploited across a broad age and size range.
Q: On Mille Lacs, harvest quotas for anglers and Chippewa netters are set by poundage. So if you allow more big walleyes to be kept, quotas will be reached more quickly.
A: True. But first we need to focus on getting the system recovered. As we do that, or when we do, we’ll have to spread harvest across a broader size of fish. How the bands accomplish that, we don’t know. We don’t know how we’ll do it, either. Again, there’s a degree of speculation in what I’m saying, because we haven’t completed all of our research.
Q: Do you envision angler regulations changing on Mille Lacs this year, from an 18- to 20-inch harvest slot, with one allowed over 28 inches, and a two-fish bag?
A: We hope to keep it where it is, but nothing is on the table right now. It appears the bite will be slow, because yellow perch are abundant for forage. We will meet with the Mille Lacs advisory committee and discuss it.