S. australasicus is a serial spawner with asynchronous oocyte development and indeterminate fecundity, and is a suitable application of the Daily Egg Production Method (DEPM). Mean spawning frequencies ranged from 2 to 11 days. Mean batch fecundity was 69,894 ±4,361 oocytes per batch. Morphological criteria were established for identifying eggs. Middle and late stage eggs can be identified with a high degree of confidence. However, significant uncertainty exists regarding the identification of early stage eggs. Only early stage eggs with a high probability of being S. australasicus were included in the analyses. A total of 4,025 eggs were collected from 2,386 plankton samples obtained during 12 research surveys. The main spawning season occurs during summer and early autumn off southern Australia and during late winter and early spring off eastern Australia. The location of spawning off southern Australia varies between years. The main spawning ground off eastern Australia is shelf waters of southern Qld and northern NSW. Most conservative estimates of spawning biomass in the areas surveyed off southern and eastern Australia were within the ranges of 45,000-70,000 t and 20,000-60,000 t. respectively. The DEPM is the stock assessment method that will underpin the Harvest strategy for the Commonwealth Small Pelagic Fishery.