During the spring season Hackettstown Hatchery workers are busy filling many of the extensive rearing ponds with spring and brook water. As these ponds are filling organic fertilizer is pumped or thrown into the ponds to initiate the growth of phytoplankton (microscopic plants) to create a food source for the incoming fry. Fry are introduced to the fertilized ponds between one and two weeks after hatching.

Plankton blooms and dissolved oxygen readings are monitored on a daily basis. Pond fertilization using pulverized alfalfa is maintained to produce a steady food supply for the growing fish. The growing food supply is made up of zooplankton (microscopic animals).

When the fingerlings have reached the size regional biologists have requested (some species, such as muskellunge and walleye, will require additional feed such as fathead minnows) the ponds will begin to be drained. As the pond's water level drops the hatchery workers don their chest waders and remove excess algae and weeds with pitchforks to provide a clear netting area.

  Once a clear netting area has been established seining (netting) will commence. Depending on fish size and pond width, seines of various sizes (1/8, 1/4 and 1/2-inch mesh) and lengths (25-80 feet) will be chosen. The fish are netted and loaded into a tank truck. The fish are transported to the intensive culture building where they are counted, measured and weighed. They are then placed in holding raceways until stocking.