The growing commercial trout industry is making a valuable contribution to fishing and fish management in Western United States. In addition to trout reared for sale as food and to provide pay-fishing, the industry is a source of trout eggs and fish not infrequently purchased to supplement production of state hatcheries. Trout are also sold for stocking of approved private and public waters. It is necessary that commercial hatcheries be licensed and state control exercised over distribution of fish from them. This prevents indiscriminate and unplanned planting of public waters and introduction, accidental or otherwise, of undesirable species of fish. Such control also aids in curtailing the spread of fish diseases. Proper regulation and inspection of commercial hatcheries can both benefit the industry and protect state waters.