The large nursery raft is called a Flupsy which is a Floating Upweller System. It is a proven way to culture small shellfish seed through their delicate "nursery" stage, from the time they come out of the hatchery until they are large enough to be sorted into trays. We use this system to boost oyster seed by increasing the water flow and feed. Under forced up-flow conditions, the seed will grow at high densities much more quickly and more uniformly that it does in natural flow conditions.
The Flupsy is built on a floating raft made that draws natural seawater through the system. Large bins with screened bottoms are lowered into openings in the frame and suspended in the seawater. Several bins are placed in a row on either side of a central enclosed channel that ends at a propeller.
The rotation of the propeller draws the water out of the central channel creating an inflow through the bottom of the seed bins.
The outflow from the bins is through a drop section on one side of the bin facing the central channel.
The bins are sorted weekly to screen different sizes into each bin to maximize the growth. The screen sizes used are 9mm, 12mm and 16mm.
The oyster seed grows from 2.3 m to 20 m or more in the Flupsy. It is moved into Growout rafts at this stage.