Strong Whitefish Fishery In Flathead Lake This Summer
By Matt Schauer


Jim Vashro, fish biologist for Region 1 and Flathead Lake, gives his thoughts on a possible whitefish bite this summer:

Well, people have been asking so I’m going to stick my neck out. Flathead Lake had very good fishing for lake whitefish in 2004-2007. Fishing was then very poor in 2007-2011. Lake whitefish are one of the most abundant fish in Flathead Lake but they are generally scattered and deep. That changes in years with good perch hatches. Large schools of young perch move near shore in mid-summer and whitefish schools move in to cash in on a great food source. Interestingly, many lake trout also show up to either eat perch or eat the fish that are eating perch.

Our theory is that weather during perch spawning and hatching, roughly mid-April to mid-May, determines perch year class strength. Strong cold fronts produce a drop in air and water temperature with accompanying strong winds. The fronts can stop spawning in its tracks and the changes can kill or dislodge perch eggs stuck to vegetation in shallow water. 2004-2007 had relatively mild springs. 2007-2011 saw one or more very strong cold fronts each spring with air temperatures dropping to the mid-20s and wind speeds up to or exceeding 30 mph. 2011 was hit even harder by high water outflows that may have flushed what few perch hatched and continued cold weather into June that delayed zooplankton development and starved what few young perch were left.

This spring saw good numbers of perch spawners and the spawn appeared to be steady. We’ve had a few windy days but nothing over mid-20s for mph and temperatures have been in the 30s or above. I would say the signs point to a good or better lake whitefish fishery in Flathead Lake this summer. We’ll see by mid July if I’m eating whitefish – or crow.

Jim Vashro, Regional Fisheries Manager for Montana Fish, Wildlife & Parks






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