Fish Growth In Hatcheries

The US Fish and Wildlife Service has adopted monthly temperature units (MTU), referred as the average monthly water temperature minus the freezing point of water. Fish grown at 4 and 19 degrees Celsius required significantly more MTU per unit of length increase than those held at 7, 10, 13 and 16 degrees Celsius. Growth at 19 degrees Celsius was less than that at 16 degrees Celsius. The ability to project the size of fish in advance is necessary for determining daily feed rates, feed orders, egg orders, stocking dates, and production schedules. Fish growth is projected in units of length, but the weight of fish of known length is often required for fish hatchery management. The food conversion is most commonly determined for a particular diet and fish strain from past station records. Calculation of the estimated food conversion is useful for evaluating potential diets, beginning a feeding schedule for new hatcheries, or investigating poor feeding efficiency.