Effects of dry pellets containing astaxanthin and squid meal on the spawning performance of striped jack Pseudocaranx dentex

This study was conducted to investigate the effect of squid meal and astaxanthin in dry pellets on the spawning performance of striped jack. Two groups of 8-year-old fish with an average bodyweight of 3.5 +/- 0.4 kg were used. The control group was fed a raw fish mix (RF) and the experimental group was fed steam dry pellets (as-DP) containing 10 p.p.m. astaxanthin and squid meal, the latter replacing half the fish meal. Each group was fed once a day, three times a week in floating net cages for a period of 5 months. Seven females and seven males were selected from each group and transferred to 65 m(3) indoor concrete tanks for spawning, where they were kept at optimum spawning conditions (22 degreesC) for 1 month. The average bodyweights of selected fish were 3.8 +/- 0.5 kg and 3.8 +/- 0.6 kg for the RF and as-DP groups, respectively. Both groups spawned a total of 18 times and the mean total egg production and egg quality, measured in terms of buoyancy, fertilization and hatching rates, showed no significant differences (P>0.05) between groups. Total larval production was 679.9 x 10(3) and 678.1 x 10(3) larvae/kg-female for the RF and as-DP groups, respectively. These results show that the combination of astaxanthin and squid meal in dry pellets for striped jack broodstock improved the overall spawning performance to a level similar to that of fish fed on RF.