Stocking Steelhead is all fine and good, to help the wild steelheads that are native to that stream to survive.

In Minnesota the SE corner of the State has 7 counties that originally had native Brook Trout.... Fishery folks started importing Brook Trout from other areas of the nation to restock, what the Fishery folks thought was a diminished stock population.

Your local streams native stock has been reduced for various reasons, stock from other fisheries are introduced. This give the native stock a better chance of survival, while the imported stock is what being caught more than the native stock...

Many years later a survey showed that the Brook Trout population was again healthy, only problem was when the DNA samples from these Brook Trout were analyzed, there all were from the original strain of Brook Trout native to those waters. There were no indications of what happened to the imported Brook Trout that were shipped in many years earlier....

Minnesota DNR has introduce Hybrid Tiger Muskies to many of the 15,453 lakes in Minnesota. Since Tiger Muskies are sterile, they are helping to balance the ecosystem, while allowing the native Northern Pike to rebuild their place in the lakes. Also the Minnesota DNR has put a minimum size limit for "Catch and Keep" of 30 inches or 40 inches, depending on these body of water.

Right now Minnesota is worried about the Asian Trout that are moving in, we have had positive DNA samples on the Mississippi River as far north as the Coon Rapids Dam just north of the Twin Cites, and also on the St. Croix River that empties into the Mississippi River at Prescott WI and Hastings MN!