The walleye now occupies about 1,700 lakes totalling 2 million acres and 100 warm-water streams totalling 3,000 miles. The best way to maintain walleye numbers is to protect the variety of lakes and streams they inhabit through existing laws limiting pollution and regulating reservoir and tailrace water levels. Shoreland zoning and related laws aid walleye and other fish by controlling lake and river shorline development and protecting aquatic plants that walleye or forage fish use for cover. It is particularly important to protect rocky spawning shoals from pollution and sedimentation. Sometimes, walleye spawning areas can be enlarged or rehabilitated by trucking loads of carefully selected boulders and cobble over the ice and dropping it at a precise location over the spawning area.
Warm weather melts the ice and deposits the substrate.
However, these artificial spawning reefs have their limits. Imagine the amount of rock that would have to be hauled onto Mille Lacs to add significantly to the thousands of acres of natural spawning habitat. The water level of large reservoirs can be manipulated to increase walleye reproduction. Low water during much of the year allows waves to crash over rocky reefs and shallows, clearing sediment from spawning areas. By raising the water level during early spring, as would happen under natural conditions, reservoir manager cover these reefs with water of adequate depth for the walleye to spawn.