Females with fully mature ovaries
were transferred to individual 120-l (120 litre) spawning
tanks. The following morning each batch of eggs was
harvested, washed and placed into a separate container
with 4-l of seawater. After thorough mixing, five 2-ml
sub-samples were fixed in 70% ethanol and later
counted on a “Bogerov” tray under a stereo dissecting
microscope to estimate egg number. The remaining eggs
were transferred to an upweller tray for hatching.
Nauplii were harvested, processed and sampled in a
similar way to egg batches to estimate nauplii number
and hatch rate. Under the protocol, nauplii were retained
as separate family batches. The number of ‘days to
spawn’ was determined as the difference in days between ablation and spawning of first and subsequent
spawns.