Eutrophication from farmland and residential development hurts spawning success by consuming oxygen along the riverbed or lake bottom, where the eggs of muskie and some forage fish incubate. Drainage of wetlands causes siltation and exaggerates the effects of flooding and drought - all to the detriment of muskie. Increased turbidity makes foraging harder for the sight-feeding muskie. Stocking The DNR normally doesn't stock muskie in lakes and rivers where they are native and self-sustaining. It simply isn't necessary or effective.
Stocking is used instead to create new muskie fisheries.
The DNR introduces muskie only to lakes that seem particularly well suited to them. An ideal lake has adequate forage, no chance of winterkill, suitable spawning areas and a size exceeding about 500 acres. Muskie then are stocked as fingerlings. If natural spawning areas are limited, stocking will continue on a regular schedule. Ideally, however, the population will become self-sustaining.