Rock flathead (Platycephalus laevigatus) is a commercially significant species in Corner Inlet, Victoria, Australia. At present, information on the biological connections between Rock Flathead fishing stocks across south-eastern Australia is limited, creating uncertainty around whether the Corner Inlet fishery is an isolated, self-replenishing stock, requiring independent management consideration. This has been recognised as a significant limitation for managers responsible for assessing the status of the fishery and in ensuring its long-term sustainability.
We adopted an integrated approach involving population genomics, otolith micro-chemistry, and acoustic telemetry, to address key questions regarding patterns of biological connectivity among Rock Flathead fishing stocks. We observed consistency across all survey methods, pointing to fish movement between Corner Inlet and stocks outside the inlet being limited. Population genetic structure indicated significant genetic structuring and gene flow limitations, analyses of otolith micro-chemistry suggested chemical profiles of fish from Corner Inlet to be distinct from all other sample locations, and acoustic telemetry indicated individual fish movements to be highly localised, with movements between fishing stocks to being highly unlikely.
Our weighted evidence approach suggests that Rock Flathead exists as isolated, self-recruiting fishing stock, which requires independent management consideration.