In both experiments, developmental abnormalities, hatching
and mortality were monitored every 2–3 days by stereomicroscopy
(Leica MZ6 with integrated DFC camera and application software
2.8.1, Leica Microsystems (Switzerland) Ltd.). Development
of eye pigmentation was recorded to quantify possible effects
on the developmental rate of the embryos. At the day of hatch,
sub-samples of hatched larvae were photographed (Leica M205C
stereomicroscope with integrated DFC camera and application software
3.6.0, Leica Microsystems (Switzerland) Ltd.) and thereafter
fixed for later histological studies. The photos of the larvae were
used for morphological analysis (measurement of total length,
yolk sac length and width) by ImageJ; Processing and Analysis in
Java. The yolk sac volume was calculated according to the formula
4/3[(L/2)2 ×
(H/2)], where L and H are maximum and minimum yolk
sac diameter, respectively (Hourston et al., 1984)