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 durat~on estimated from otoliths of post-larval King George whiting Sillaginodes punctata collected from bays and inlets of central Victoria, Australia, and reverse simulation with a numerical hydrodynamic model, to estimate spawning sites and larval advection pathways. Larval duration increased from west to east for post-larvae entering Port Phillip Bay, Western Port and Corner Inlet. The period of recruitment to bays and inlets was relatively fixed; the longer larval durations were associated with earlier spawning times. Larval durations for post-larvae entering Port Phillip Bay were longer for 1989 compared with 1994 and 1995. Reverse modelling based on larval durations for the 3 bays in 1995 suggested that most post-larvae were derived from spawning in western Victoria and southeastern South Australia. The centre of the predicted spawning &stribution was ca 400 to 500 km from the recruitment sites and the region of intense spawning was spread along approximately 300 km of coastline. For Corner Inlet, however, a small proportion of the spawning may have occurred in central Victoria, within 200 km of the recruitment site, with larvae transported in a clockw~se gyre around Bass Strait. The predicted spawning area for post-larvae from Port Phillip Bay was similar in the 3 yr examined.