Recreational fishing can exert strong, directional selection on wild fish populations, with the potential to drive evolutionary change across a range of traits over relatively short timescales. In lutruwita (Tasmania), southern sand flathead (Platycephalus bassensis) dominate recreational finfish catches and were classified as depleted in 2023, with 80% of catches originating from southern populations exposed to intense fishing pressure while northern populations experience comparatively less exploitation. These regions show pronounced differences in life history traits such as size at age and growth rate, but whether these differences have a detectable genetic component, reflecting fisheries-induced evolution, environmental drivers, or a combination of both, remains unresolved. This study aims to characterise the population and genetic structure of southern sand flathead across 11 sampling locations in Tasmania and Victoria using Single Nucleotide Polymorphism (SNP) genotyping via genome complexity reduction-based sequencing. Contemporary samples will be compared against archived historical specimens (circa 1994) to track potential temporal shifts in genetic diversity. Neutral SNPs will be used to assess gene flow, connectivity, and isolation by distance (FST, GST, Jost's D), while non-neutral SNPs will be mapped to an annotated reference genome to identify loci potentially under selection. These findings aim to establish a baseline genetic framework for this depleted species and provide insight into whether size-selective harvesting is leaving measurable signatures in population genetic structure, a critical step in disentangling the relative contributions of fishing pressure and environmental change to contemporary evolution in this species.