The white paper from the sa fisheries research i read a few years back said a large mulloway congregation off the murray mouth to breed around sept to november (not every year somewhere between every 3-5 years) the ova is then swept up in currents that head out into the southern ocean these then over the following year or 2 grow to a few centimetres long & drift back in on landward based currents the fingerlings take up refuge in estuarys & creeks open to the sea & spend a few years around these areas (coorong is one of the major nurserys & the worms that live in there are one