A good trout stream is a lucky mix of these ingredients that can be improved only within the limits of basic productivity. A Study in Contrasts North Shore streams and southeast streams differ in almost all ways that are important to trout. Many North Shore streams flow from warm water lakes that have northern pike and walleye populations. Joining small, brushy tributaries and racing through cool, shaded gorges, these creeks become cold enough in their middle reaches to support brook trout. Southeast trout streams rise from springs, and may support brook trout in their headwaters.
Brown trout prevail in the middle reaches.
Warm water tributaries, dependent on runoff, may join the main stream as it gradually changes from a trout stream to a warm water river harboring walleye, northern pike, bass and catfish. Though brook, brown and rainbow trout evolved to breed and live in streams, they grow bigger when they are put into lakes. So, the DNR stocks stream trout in about 160 lakes to give anglers a chance to catch trophy trout-brookies up to six pounds, rainbows up to 10 and browns as large as 16. In selecting lakes for stream trout, the DNR looks for lakes that are cold, well-oxygenated and free of pollutants. Ideally, the basins have no inlets or outlets that would allow stocked trout to leave or other fish to enter the lake and eat the trout or compete with them for food.