Texas has 29 fish advisories. California has about 160. I went through both of those because I wanted the app I built to have accurate data. Minnesota broke the pattern completely, and it's worth explaining why.
There is no list of advisories to go find here. MDH publishes guidance for every lake in the state, and DNR carries it per-lake inside LakeFinder. 460 of those lakes get their own numbers because they tested worse than the baseline. Every other lake is covered by a statewide set that applies whether or not anyone has ever sampled it.
So in Minnesota "my lake isn't on the list" isn't a thing. There's always an answer. The question is only which of three sets you're under.
The statewide set, for adults: sunfish, crappie, perch, bullheads, whitefish, cisco and all three trout are four meals a week. Walleye, pike, both bass, channel and flathead cat and lake trout are one a week. Muskie is one a month. It's mercury on basically all of it.
For kids under 15 and anyone pregnant or who might become pregnant, the same set gets a lot tighter, and this is where the sizes matter. Walleye over 20 inches is do not eat. Pike over 28 inches is do not eat. Muskie is do not eat at any size. Under those lengths it's one a month. Crappie and perch drop from four a week to one.
Then there's the northeast set, and this is the part I'd guess most people here don't know. Cook, Lake and St. Louis counties have their own guidance that replaces the statewide numbers, and it is stricter in a specific way: walleye goes do-not-eat at 18 inches instead of 20, and pike at 26 instead of 28. Two inches on each. Black crappie goes from four meals a week to two. If you're keeping eaters out of the Arrowhead and using the statewide numbers in your head, you're two inches off on the two fish you're most likely to be holding.
The lakes with their own advisories are the ones that got sampled and came back worse. Lake Elmo is the one I'd point at: do not eat, everyone, any size, any species — that's PFOS, not mercury.
It's a metro lake with a boat ramp. Rainy Lake has its own numbers rather than the regional default. Duluth/Superior Harbor, Pepin, Big Sandy, Bemidji and Osakis all carry their own. 2,842 species-and-size recommendations across those 460 waters, mercury on most of it, PCBs and PFOS on the rest.
Now the part that took me longest to work out.
MDH only lists a species on a lake's page where that lake is stricter than the baseline for that group. So you'll open a lake, see walleye listed for adults, see nothing listed for kids, and reasonably conclude there's no restriction for kids on that lake. There is. It's whatever the baseline says — statewide or northeast, depending on the lake. The absence is a "we didn't need to tighten this one," not a "you're clear." I got that wrong on the first pass and it silently dropped the stricter half of the advice on 244 lakes before I caught it.
I'm not trying to talk anyone out of eating fish, and Minnesota's numbers are honestly generous compared to most states I've been through — four meals a week on panfish is not a warning, it's a green light. But one a week versus one a month versus do-not-eat is a real difference, and "which set covers this lake" shouldn't take a weekend to answer.
Mods okayed me mentioning it, so: it's all in one place at https://livewell-app.com/advisories/minnesota — every lake with its own advisory, the statewide set, the northeast set, and each lake's page tells you which one covers it. No signup, works in a phone browser.
There's also an app built for using this on the water. It works offline, figures out which lake you're standing on, and you tell it what you caught. It even has a feature to identify the fish you've caught based on a photo, and a whole ton of other useful features. Android is out now, the iPhone version is in progress.
One caveat while I'm here, since this sub will find it: I also pulled the lake-specific harvest regs off LakeFinder, so the slots and bag limits are in there too — Mille Lacs's walleye window, the release-over-30 pike lakes, the catch-and-release lakes. Those attach by DOW number rather than by lake name, so they should be on the right water, but if you hit a lake showing the statewide default when you know it has a special reg, tell me the lake and I'll fix it.
Two questions:
Did anyone here know the northeast counties run on a different set than the rest of the state? I'd genuinely like to know whether that's common knowledge up there or not.
And has anyone seen MDH advisory signage at a public access anywhere in the state? Every state I've done this for publishes the guidance and then seemingly never puts it anywhere a person standing at the water would see it.
Source: r/FishingMinnesota · by /u/laszlof