Sand Whiting are one of the main
species currently under culture at Aquablue Seafoods and we are constantly
experimenting with our hatchery techniques and fingerling grow out systems.
Sand Whiting are a small fish that only grows to around 50cm and up to just over 1kg
in weight. Most large whiting are around the 350g mark, and our largest female breeder
is 780g in weight. They are silvery/grey on top, white on the bottom and have yellow
fins. They are a common recreational fishing species in Australia and are both an
excellent sporting fish and an excellent eating fish.
2006 was our first year at breeding whiting and we did reasonably well with large
numbers of eggs and larvae produced. Whiting are spot breeders breeding over several
days with the eggs being buoyant and floating to the surface of the tank.
Initial breeding was by natural methods in a 10,000 litre recirculation system. The
Whiting were happy and well fed so they bred naturally without any intervention on our
part. In the large 10,000 ltr system the eggs would just float to the surface and flow
with the water out of the tank into a skimmer basket that we would empty out each day
and place the eggs into incubation tanks.
The second and third breeding were by hormone injecting the Whiting with 250 - 500
IU of HCG and placing them into smaller 1,400 ltr tanks. These were still static water
tanks with just heaters and aerators. Eggs would just be scooped from the tanks
several times per day and then transferred to incubation tanks.
Whiting eggs were hatched in incubation tanks and kept there until the larva were
ready to feed and then released into outside earthen ponds. The outside ponds are 60m
by 30m and filled with 1.5m of marine salt water. Ponds were initially only filled
with 600mm of water and fertilised to grow algae and zooplankton for the larval
whiting. Just 2 days before release into the pond the pond was flooded with new marine
water to ensure good water quality for the fragile baby Whiting.
The larval Whiting were transferred from the hatchery incubation tanks to a 1000 ltr
tank floating in the outside pond. Initially 200 ltr of water and 100,000 larva were
added from the hatchery to this empty floating tank. Then over a 12 hour period water
from the pond was slowly added to acclimatize the baby Whiting to the pond water.
After this 12 hour acclimatization the Whiting were released into the pond to feed on
the zooplankton that we had grown in the pond. This food source was supplemented by
releasing rotifers grown in our 10,000 ltr rotifer tanks directly into the pond.
The larva will be ongrown into fingerlings for sale to other fish farms and
researchers as well as transferred inside to our recirculation systems to be ongrown
for the restaurant trade.