Genetic analyses show high levels of connectivity for King George whiting (Sillaginodes punctatus) across two states

King George whiting, Sillaginodes punctatus, is an important commercial and recreational fish species in southern Australia. This species has a complicated life history, involving a number of habitat shifts at different... [ view full abstract ]

King George whiting, Sillaginodes punctatus, is an important commercial and recreational fish species in southern Australia. This species has a complicated life history, involving a number of habitat shifts at different developmental stages. Their extended larval phase (up to 160 days) means there is potential for widespread dispersal before settlement, which occurs in seagrass habitats of sheltered bays and inlets across South Australia and Victoria.

The number of distinct spawning grounds and the patterns of connectivity and dispersal between populations is currently poorly understood. To date only one spawning location for this species has been identified in South Australia, and it is remains unclear to what the extent Victorian stocks are dependent on these for recruits for maintaining populations. Understanding patterns of genetic connectivity and population structure will therefore provide important information for management regarding whether King George whiting in south-eastern Australian waters should be managed as a single stock, or as multiple populations.

Genetic analysis of population structure of post-larvae collected in bays across South Australia and Victoria using both microsatellites and single nucleotide polymorphisms (SNPs) has shown no significant genetic differentiation between states or regions. These high levels of connectivity suggest that King George whiting in South Australia and Victoria are part of a single large panmictic stock.