UVI Research and Technology Park

Nursery System

The UVI Tilapia Nursery is a recirculating aquaculture system capable of producing 100,000 50-gram tilapia fingerlings each year.

The tilapia nursery consists of 12 rearing tanks, filter tanks, water circulating pump and regenerative air blower.

Fry are stocked at 1,000/m2, 2,000 fish/tank.  One tank is harvested and restocked each week.

Fry are stocked at 1-g and reared to 50-g in a 12 weeks. 

Solid waste is removed by a drum filter and dissolved nitrogen waste is removed in a fluidized bead media filter.

Considerations for nursery management

  • Water flow/exchange rate – 1x per hour
    • A faster flow rate will remove waste faster and provide for a cleaner growing environment
      • But will require more energy to be used for swimming against the current
      • Will require higher electricity consumption to pump water faster.
  • A slower flow rate will require less swimming and energy use by the fish
    • But water quality will be less than optimal for fish health and growth
    • Will lower the electrical requirements of the water pump
    • Feed ad libitum 4 X each day for 30 minutes per feeding
      • Ad libitum feeding allows for precise rationing of daily feed intake and best feed conversion
        • But requires more labor and time
  • Fixed rate feeding saves time
    • But can lead to underfed fish and slow growth
    • Can lead to overfed tanks and wasted feed
    • Stock once – harvest once
      • Tanks should be stocked at recommended rate and harvested completely 12 weeks later
      • Stock splitting
        • Stresses fish during transfer
        • Fish growth slows as peak biomass is reached before splitting