Sandfish hatchery techniques - English version - ACIAR

SPAWNING
Preparing broodstock for spawning
1. Use a bare, flat-bottomed tank up to 2 m 3 . Provide
cover and heaters to maintain constant water
temperature at night.
2. Clean the tank and disinfect with chlorine
(sodium hypochlorite). Fill with 1-µm filtered and
UV-sterilised seawater at ambient temperature
(30°C, give
a cold shock treatment for 1 hour before the
heat shock. To do this, reduce the level of water
in the spawning tank and add sealed plastic
bags containing ice to quickly lower the water
temperature by 5°C below ambient. Then apply
heat shock as above.
h After thermal stimulation, replace water with
new water at ambient temperature, keeping the
animals covered.
Gonad extraction method
h Dissect a few animals to extract gonads from 1 to
2 ripe males.
h Store the gonads at 5°C to extend the viability of
the sperm.
h Use the sperm as a spawning stimulant by adding
blended fresh male gametes to the spawning tank
at ambient water temperature.
Water pressure
h Leave broodstock to dry in the tank in the shade
for about half an hour before subjecting them to a
powerful jet of seawater for a few minutes.
h Return broodstock to the spawning tank at
ambient water temperature.
SPAWNiNG
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