Determination of spawning areas and larval advection pathways for King George whiting in southeastern Australia using otolith microstructure and hydrodynamic modelling. I. Victoria

We used larval duration estimated from otoliths of post-larval King George whiting Sillaginodes punctata collected from bays and inlets of central Vic toria, Australia, and reverse simulation with a numerical hydrodynamic mode l, to estimate spawning sites and larval advection pathways. Larval duratio n increased from west to east for post-larvae entering Port Phillip Bay, We stern Port and Corner Inlet. The period of recruitment to bays and inlets w as relatively fixed; the longer larval durations were associated with earli er spawning times. Larval durations for post-larvae entering Port Phillip B ay were longer for 1989 compared with 1994 and 1995. Reverse modelling base d on larval durations for the 3 bays in 1995 suggested that most post-larva e were derived from spawning in western Victoria and southeastern South Aus tralia. The centre of the predicted spawning distribution was ca 400 to 500 km from the recruitment sites and the region of intense spawning was sprea d along approximately 300 km of coastline. For Corner Inlet, however, a sma ll proportion of the spawning may have occurred in central Victoria, within 200 km of the recruitment site, with larvae transported in a clockwise gyr e around Bass Strait. The predicted spawning area for post-larvae from Port Phillip Bay was similar in the 3 yr examined.