We estimated pelagic larval duration (PLD) and age from the otolith microstructure of post-larval and juvenile gag, Mycteroperca microlepis (Goode and Bean, 1879). These estimates were used to: (1) estimate spawning periods; (2) evaluate lunar periodicity in spawning; (3) assess relationships between PLD and fertilization date, ingress date, capture date, and size at capture; and (4) compare juvenile growth rates in two consecutive years and with rates determined in previous studies. Our findings support the timing (January–April) of fishing closures on aggregations of spawning gag in the southeast US and suggest that post-settlement survival is not linked to PLD.