A diet of frozen squid or tuna was provided ad libitum on a daily basis. Four individuals were immature. Various lengths of PVC pipes were placed in the tanks for shelter. Aquarium nets used as egg collectors were placed in the drainage system of each tank and checked each morning for the presence of spawned eggs. Temporal changes in number of spawned eggs from three tanks containing E. merra broodstock held at Guam Aquaculture Development and Training Center.
Circles indicate phases of the moon.
At regular intervals spawned eggs were present for two to five consecutive days with the largest number of spawned eggs occurring on the second or third day after spawning had begun. Temporal changes in the occurrence and number of spawned eggs are presented in Fig. 1. The appearance of spawned eggs from each of the holding tanks exhibited a similar pattern although fish in Tank 2 did not spawn between 28 November and 4 December, indicating some variability in the spawning activity for each tank. Since there were not more than three females per tank, it can be concluded that a single female will spawn more than once during a spawning run, although it remains to be determined whether all of the females spawn repeatedly during the same time interval. It also appears that the spawning of the broodstock is correlated to the lunar cycle, with spawning activity occurring just prior to the new and full phases of the moon.