LivewellMontana · Lake
Flathead Lake
Is the fish you caught here safe to eat? Below is every consumption advisory on file for Flathead Lake, by species and size, in plain English — plus what's legal to keep.
2 species with advisories · contaminants: Mercury, PCBs
What's safe to eat from Flathead Lake
Lake Trout
| Size | Who | Guidance |
|---|---|---|
| 6–10" | General population | Limit to three meals per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to one meal per week due to elevated Mercury and PCB. | |
| 10–14" | General population | Limit to three meals per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to one meal per week due to elevated Mercury and PCB. | |
| 14–18" | General population | Limit to one meal per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to two meals per month due to elevated Mercury and PCB. | |
| 18–22" | General population | Limit to one meal per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to two meals per month due to elevated Mercury and PCB. | |
| 22–26" | General population | Limit to one meal per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to one meal per month due to elevated Mercury and PCB. | |
| 26–30" | General population | Limit to one meal per month due to elevated Mercury and PCB. |
Source: official advisory· updated 2026-09-22
Lake Whitefish
| Size | Who | Guidance |
|---|---|---|
| 14–18" | General population | Limit to one meal per week due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to two meals per month due to elevated Mercury and PCB. | |
| 18–22" | General population | Limit to two meals per month due to elevated Mercury and PCB. |
| Women who may become pregnant & children under 15 | For women who may become pregnant, pregnant or breastfeeding women, and children under 15: limit to one meal per month due to elevated Mercury and PCB. |
Source: official advisory· updated 2026-09-22
How to prepare fish from Flathead Lake
Some contaminants build up in fat and skin, so cleaning and cooking can lower your exposure. Others — mercury and PFAS — are in the muscle itself and trimming does nothing.
PCBs
- Skin the fish — most of the contaminant sits in the fat just under the skin.
- Trim the fatty areas away: the belly flap, the top of the back, and the dark lateral line down each side.
- Cook on a rack — grill, broil, or bake — so the fat drips off the fillet.
- Throw the drippings out; don't use them for soup, sauce, or chowder.
- Choose smaller, younger fish — they've had less time to build it up.
Is it legal to keep?
These are Montana's statewide limits — a water-specific rule may override them. Always verify the current regulations before keeping a fish.
| Species | Size | Daily limit | Open season | Keep season |
|---|---|---|---|---|
| Rainbow Trout | — | 5 | Year-round | Same as open |
| Brown Trout | — | 5 | Year-round | Same as open |
| Cutthroat Trout | — | 3 | Year-round | Same as open |
| Bull Trout | — | 0 | Year-round | Same as open |
| Brook Trout | — | 10 | Year-round | Same as open |
| Arctic Grayling | — | 0 | Year-round | Same as open |
| Mountain Whitefish | — | 20 | Year-round | Same as open |
| Walleye | — | 5 | Year-round | Same as open |
| Sauger | — | 5 | Year-round | Same as open |
| Northern Pike | — | 10 | Year-round | Same as open |
| Smallmouth Bass | — | 5 | Year-round | Same as open |
| Largemouth Bass | — | 5 | Year-round | Same as open |
| Lake Trout | — | 3 | Year-round | Same as open |
| Kokanee | — | 10 | Year-round | Same as open |
| Black Crappie | — | 15 | Year-round | Same as open |
| White Crappie | — | 15 | Year-round | Same as open |
| Yellow Perch | — | — | Year-round | Same as open |
| Bluegill | — | — | Year-round | Same as open |
| Burbot | — | 2 | Year-round | Same as open |
Official rules: Montana — Montana FWP standard-district default