Concerns over water pollution from fish hatcheries have resulted in the design of various systems to control suspended solids in hatchery discharges. The State of Michigan has incorporated baffles in its hatchery raceways to move the solids to the foot of the raceways where they can be removed. This has eliminated the need for brushing raceways and for treating the large volume of water that resulted from this activity. All cold water species (Salvelinus namaycush), except lake trout, have adapted well to baffles in raceways.