Evaluation of an open formula reference diet on California yellowtail ( Seriola dorsalis ) Broodstock

The reliable production of marine finfish is contingent on the quantity and quality of the eggs available from the broodstock. Proper broodstock nutrition is critical for maintaining a supply of good quality eggs. Here, we compared an open‐formula reference diet (OFRD; 18 mm pellet) and a commercial broodstock diet (Europa, Skretting; 12 mm pellet) when fed to California yellowtail (CYT; Seriola dorsalis ). The aim was to determine if egg production and quality were impacted by these formulated diets. A total of 16 F2 generation CYT broodstock (2 females; 2 males per tank) were held in four 10 m 3 tanks under ambient temperature and photoperiod. We alternated each diet twice over four 6‐week periods through the spawning season. The OFRD‐fed fish spawned 20 times and produced 16.9 million eggs with an average viability of 53.6%, while the Europa‐fed fish spawned 21 times and produced 18.1 million eggs with an average viability of 53.8%. There were no significant differences in total eggs produced, viability rates, egg morphometrics, hatch rates, or survival to first feeding. There were significant biochemical differences between the diets as well as in notochord length at hatch. Based on the results from these trials, the OFRD can be used in future experimental work as a tool to determine dietary needs for CYT broodstock.