Sandfish hatchery techniques - English version - ACIAR

NURSERY
Culture of early juveniles
At 25–35 days old, juveniles are transferred from
larval tanks into nursery tanks. Nursery tanks are
raceways, bigger pools or large tanks of 6 to 10 m 3 ,
usually made of fibreglass, flexible PVC-cloth liner or
concrete. The water in the nursery tanks should be at
least 60 cm deep (maximum 1 m). Nursery tanks need
to be conditioned prior to the transfer to ensure food
is available for the juveniles.
Procedure for conditioning nursery tanks:
h Clean all tank surfaces. Install the aeration system
and bare, clean settlement surfaces.
h Fill the tank with 1-µm filtered and UV-sterilised
seawater, fully immersing the settlement surfaces
(i.e. a depth of 60–70 cm).
Figure 40. Nursery tanks.
h
h
h
Inoculate the water with fresh diatom cultures at
a rate of 6–7% of the total volume of water in
the tank. Add sodium metasilicate (5 g/m 3 ) and a
general fertiliser (7 g/m 3 ). Switch on the light.
Turn off the water flow for the first 3–4 days to
allow a diatom coating to develop on the plates or
other settlement surfaces and tank walls. Maintain
moderate aeration and mix the water daily.
Keep the water temperature constant and warm
(26–28°C).
After conditioning, the nursery tanks are ready to
receive pentactula larvae and early juveniles.
NURSERY
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