REARING AND INDUCING SPAWNING IN CAPTIVE PACIFIC SARDINE (SARDINOPS SAGAX)

From 2014 to 2018, we conducted laboratory experiments to develop methods for inducing spawning in Pacific sardine (Sardinops sagax). Wild caught immature S. sagax were acclimatized for three months, reared until they were fully mature, and then induced to spawn. Fish reared at 14.5 degrees-18 degrees C and 4-12 h day-light, and fed a vitamin-enriched diet, were mature by 27 months. Fish treated with hormones prior to 24 months of rearing did not spawn, but those injected at 27 and 39 months spawned and naturally fertilized their eggs.The successful induction method consisted of human chorionic gonadotropin injections followed by a combination of carp pituitary extract and Domperidone injections 24 h later. Spawning occurred approximately 20 h after the second hormonal treatment. Eggs collected at 27 months and incubated at 11 degrees, 13 degrees, and 15 degrees C produced healthy larvae, but those spawned at 39 months did not survive to the larval stage. Ovaries were fully matured in February, but their oocytes regressed by May, suggesting that under controlled environment conditions S. sagax followed a seasonal maturity cycle similar to that of the naturally spawning population off California.