Beginning 48 h post-hormone treatment, the fish were examined hourly by a gentle abdominal massage. Those showing signs of ovulation were immediately transferred to a clove oil water bath (0.03 mL/L), and eggs were stripped by gentle abdominal massage under dry conditions into a dry bowl. Eggs were weighed using a balance (PCB 1000-2, Kern, Germany with accuracy of 0.01 g) separately for each female. Three samples of ~1 g per spawning were randomly selected and weighed using a balance (ALJ 220-4, Kern, Balingen, Germany) with accuracy of 0.0001 g and counted for determination of absolute fecundity (total number of eggs per female) and relative fecundity (total number of eggs per kg BW).
After fertilization according to a previously described method [28 (link)], three samples of ~100 eggs were counted and incubated in separate incubators in a recirculating system at 16 ± 0.5 °C as described by Blecha et al. [6 (link)]. Hatching began on the fifth day post-spawning and the freshly hatched free-swimming larvae were counted. The hatching rate was determined as follows:
where NL is the number of hatched larvae and NE is the total number of eggs stocked in the incubator.
After fertilization according to a previously described method [28 (link)], three samples of ~100 eggs were counted and incubated in separate incubators in a recirculating system at 16 ± 0.5 °C as described by Blecha et al. [6 (link)]. Hatching began on the fifth day post-spawning and the freshly hatched free-swimming larvae were counted. The hatching rate was determined as follows:
where NL is the number of hatched larvae and NE is the total number of eggs stocked in the incubator.